WO2020158006A1 - Dc power supply system and power system - Google Patents

Dc power supply system and power system Download PDF

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Publication number
WO2020158006A1
WO2020158006A1 PCT/JP2019/023175 JP2019023175W WO2020158006A1 WO 2020158006 A1 WO2020158006 A1 WO 2020158006A1 JP 2019023175 W JP2019023175 W JP 2019023175W WO 2020158006 A1 WO2020158006 A1 WO 2020158006A1
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WIPO (PCT)
Prior art keywords
power
output
voltage
current
conversion circuit
Prior art date
Application number
PCT/JP2019/023175
Other languages
French (fr)
Japanese (ja)
Inventor
裕則 金野
山田　剛
壮平 岡本
健介 村島
Original Assignee
パナソニックＩｐマネジメント株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Priority claimed from JP2019014473A external-priority patent/JP7038309B2/en
Priority claimed from JP2019023375A external-priority patent/JP7138306B2/en
Priority claimed from JP2019092235A external-priority patent/JP7174897B2/en
Application filed by パナソニックＩｐマネジメント株式会社 filed Critical パナソニックＩｐマネジメント株式会社
Priority to CN201980090722.1A priority Critical patent/CN113383286B/en
Publication of WO2020158006A1 publication Critical patent/WO2020158006A1/en

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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/66—Regulating electric power
    • G05F1/67—Regulating electric power to the maximum power available from a generator, e.g. from solar cell
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac

Definitions

  • the present disclosure relates to a DC power supply system and a power system.
  • An example of the power generation system is a solar power generation system that uses a solar power generation panel to generate power.
  • Another example of the power generation system is a fuel cell power generation system that uses a fuel cell to generate power.
  • Patent Document 1 describes that the output voltage of the photovoltaic power generation system and the fuel cell power generation system is changed to a predetermined voltage by power conversion.
  • the maximum power point tracking control is also called MPPT control.
  • the MPPT control maximizes the electric power extracted from the solar power generation system.
  • a direct-current power converter can be connected to the solar power generation system to cause the direct-current power converter to execute MPPT control.
  • a DC power converter When configuring a power system that can execute MPPT control of a solar power generation system, a DC power converter is designed so that it can execute MPPT control of the solar power generation system.
  • the present disclosure is a DC power supply system including a fuel cell power generation system, in which MPPT control is executed in a state of being connected to the DC power conversion device designed as described above, so that the DC power is supplied from the fuel cell power generation system.
  • a DC power supply system from which electric power can be taken out to a power converter.
  • a fuel cell power generation system A characteristic conversion circuit to which DC power output from the fuel cell power generation system is input, the characteristic conversion circuit performing characteristic conversion control,
  • the characteristic conversion control provides an output voltage-output power characteristic that maximizes the output power of the characteristic conversion circuit when the output voltage of the characteristic conversion circuit has a certain value
  • the characteristic conversion control includes a first feedback control and a second feedback control, The first feedback control is control performed when the output current of the characteristic conversion circuit is relatively small, The second feedback control is control performed when the output current of the characteristic conversion circuit is relatively large, When the first feedback control and the second feedback control are switched, the output voltage of the characteristic conversion circuit becomes the certain value.
  • the DC power supply system includes a fuel cell power generation system.
  • the MPPT control is executed by the DC power conversion device.
  • electric power can be taken out from the fuel cell power generation system to the DC power converter.
  • FIG. 1 is a block diagram of an electric power system during grid interconnection.
  • FIG. 2 is a block diagram of the power system during a power failure.
  • FIG. 3A is a diagram for explaining the VP characteristic obtained by the characteristic conversion circuit.
  • FIG. 3B is a diagram for explaining the VP characteristic of the comparative form.
  • FIG. 4 is a diagram illustrating an example of the characteristic conversion circuit.
  • FIG. 5 is a diagram for explaining the current sensor.
  • FIG. 6 is a diagram for explaining the first shunt regulator.
  • FIG. 7 is a diagram for explaining the second shunt regulator.
  • FIG. 8 is a diagram showing a specific example of the characteristic conversion circuit.
  • FIG. 9 is a diagram showing another example of the characteristic conversion circuit.
  • FIG. 10 is a diagram showing another specific example of the characteristic conversion circuit.
  • FIG. 10 is a diagram showing another specific example of the characteristic conversion circuit.
  • FIG. 11 is a diagram showing an example of the characteristic conversion circuit.
  • FIG. 12 is a diagram illustrating an example of the adjuster.
  • FIG. 13 is a diagram for explaining an influence due to individual variation of the current sensor.
  • FIG. 14 is a diagram for explaining an influence due to individual variation of the current sensor.
  • FIG. 15 is a diagram for explaining the influence of the individual variation of the current sensor.
  • FIG. 16 is a block diagram of the power system at the time of grid interconnection.
  • FIG. 17 is a block diagram of the power system at the time of power failure.
  • FIG. 18 is a diagram for explaining the output characteristic of the characteristic conversion circuit.
  • FIG. 19 is a diagram for explaining the output characteristic of the characteristic conversion circuit.
  • FIG. 20 is a diagram illustrating an example of the characteristic conversion circuit.
  • FIG. 21 is a diagram for explaining the first shunt regulator.
  • FIG. 22 is a diagram for explaining the current sensor.
  • FIG. 23 is a diagram for explaining an influence due to individual variation of the current sensor.
  • FIG. 24 is a diagram for explaining an influence due to individual variation of the current sensor.
  • FIG. 25 is a diagram for explaining the adjustment of the switching current by the variable voltage.
  • FIG. 26 is a diagram showing a specific example of the characteristic conversion circuit.
  • FIG. 27 is a block diagram of the power system during grid interconnection.
  • FIG. 28 is a block diagram of the power system at the time of power failure.
  • FIG. 29A is a diagram for explaining the VP characteristic obtained by the characteristic conversion circuit.
  • FIG. 29B is a diagram for explaining the VP characteristic of the comparative form.
  • FIG. 29A is a diagram for explaining the VP characteristic obtained by the characteristic conversion circuit.
  • FIG. 29B is a diagram for explaining the VP characteristic of the comparative form.
  • FIG. 29A is
  • FIG. 30 is a diagram for explaining the output characteristic of the characteristic conversion circuit.
  • FIG. 31 is a diagram illustrating an example of the characteristic conversion circuit.
  • FIG. 32 is a diagram for explaining an influence due to individual variation of the current sensor.
  • FIG. 33 is a diagram for explaining the adjustment of the switching current by the variable voltage.
  • FIG. 34 is a diagram for explaining the output characteristics of the adjusted characteristic conversion circuit.
  • FIG. 35 is a diagram showing a specific example of the characteristic conversion circuit.
  • the ordinal numbers first, second, third... May be used.
  • an element has an ordinal number, it is not essential that there be a younger element of the same type.
  • the term third connection point is not used to mean that the first connection point and the second connection point are necessarily present with the third connection point.
  • the ordinal number can be changed if necessary.
  • the route may be used.
  • the route may have a plurality of lines.
  • connection points and the like For example, the single-phase three-wire type path has two ungrounded lines and one grounded line. It should be understood that the connection point between the single-phase three-wire routes is used to indicate a range of regions including the connection points of the respective lines in the route.
  • the combination of the output current, output voltage, and output power of the characteristic conversion circuit may be referred to as the operating point of the characteristic conversion circuit.
  • the operating point when the output power of the characteristic conversion circuit becomes maximum may be referred to as the maximum power point.
  • FIG. 1 and 2 are block diagrams of a power system 300 according to the first embodiment.
  • FIG. 1 shows an example of the flow of electric power during grid interconnection.
  • FIG. 2 shows an example of the flow of electric power at the time of power failure.
  • the solid line represents that electric power is flowing through the electric line.
  • the dotted line represents that no electric power is flowing in the electric line.
  • VAC1 and VAC2 represent alternating voltage.
  • the effective value of the AC voltage V AC1 is smaller than the effective value of the AC voltage V AC2 .
  • the effective value of the AC voltage V AC1 is, for example, 100V.
  • the effective value of the AC voltage V AC2 is, for example, 200V.
  • the electric path or route of the AC voltage V AC1 is realized by two single-phase two-wire electric wires.
  • the electric line or path of the AC voltage V AC2 is realized by two ungrounded lines of the three single-phase three-wire type electric wires.
  • the power system 300 is connected to the grid power supply 200. Power can be supplied to the power system 300 from the grid power supply 200. In addition, the power system 300 can cause the system power supply 200 to reversely flow power.
  • the power system 300 includes a power station 10, a fuel cell power generation system 40, a substrate 60, solar power generation systems 31 and 32, a power storage device 25, a power switching unit 28, a first distribution board 80, and a first power distribution panel 80. It has a distribution board 90, loads 251, 252 and 253, and an outlet 260.
  • the first distribution board 80 may be referred to as a main distribution board 80.
  • the second distribution board 90 may be referred to as an independent distribution board 90.
  • the power station 10 includes a DC power converter 20, a first DC bus 11, a fourth DCDC converter 12, and a first inverter 13.
  • the DC power conversion device 20 is designed to be able to perform maximum power point tracking control for a photovoltaic power generation system that maximizes output power when the output voltage is within a predetermined range.
  • the solar power generation system is a system that uses a solar power generation panel to generate power.
  • the maximum power point tracking control may be referred to as MPPT control.
  • DC power is input to the DC power converter 20 from the solar power generation systems 31 and 32 and the fuel cell power generation system 40.
  • the DC power output from the DC power converter 20 is supplied to the first DC bus 11.
  • the DC power conversion device 20 includes a first DCDC converter 21, a second DCDC converter 22, and a third DCDC converter 23.
  • DC power is input to the first DCDC converter 21 from the fuel cell power generation system 40.
  • DC power is input to the second DCDC converter 22 from the first solar power generation system 31.
  • DC power is input to the third DCDC converter 23 from the second solar power generation system 32.
  • the DC power output from these DCDC converters 21, 22, and 23 is supplied to the first DC bus 11.
  • the fourth DCDC converter 12 converts the DC power input from the first DC bus 11 into DC power having a different voltage.
  • the DC power converted by the fourth DCDC converter 12 is supplied to the power storage device 25.
  • the fourth DCDC converter 12 converts the electric power input from the power storage device 25 into DC electric power having a different voltage, and supplies the DC electric power to the first DC bus 11. That is, the fourth DCDC converter 12 is a bidirectional DCDC converter.
  • the fourth DCDC converter 12 operates so that the terminal voltage of the power storage device 25 falls within the rated range.
  • the first inverter 13 converts DC power into AC power. Specifically, the first inverter 13 converts the DC power input from the first DC bus 11 into AC power of the voltage V AC1 or the voltage V AC2 . When the first inverter 13 can obtain the AC power having the voltage V AC1 , the power is supplied to the power switching unit 28. When AC power of voltage V AC2 is obtained by the first inverter 13, the power is supplied to the main distribution board 80.
  • the first inverter 13 can also convert the AC power of the voltage V AC2 input from the system power supply 200 via the main distribution board 80 into DC power.
  • the DC power thus obtained is supplied to the power storage device 25 via the first DC bus 11 and the fourth DCDC converter 12.
  • the power system 300 includes at least one solar power generation system that maximizes output power when the output voltage is within a predetermined range.
  • the DC power generated by the at least one solar power generation system is supplied to the DC power converter 20.
  • the solar power generation systems 31 and 32 correspond to the solar power generation systems in which the output power is maximum when the output voltage is within the predetermined range.
  • the first solar power generation system 31 has at least one solar power generation panel 36.
  • the first solar power generation system 31 uses the at least one solar power generation panel 36 to generate power.
  • the second solar power generation system 32 includes at least one solar power generation panel 37.
  • the second solar power generation system 32 uses the at least one solar power generation panel 37 to generate power.
  • the DC power generated by the solar power generation systems 31 and 32 is supplied to the DC power converter 20.
  • the fuel cell power generation system 40 is a system that uses a fuel cell 41 to generate power.
  • the DC power generated by the fuel cell power generation system 40 can be supplied to the DC power converter 20.
  • the AC power generated by the fuel cell power generation system 40 may be supplied to the main distribution board 80.
  • the fuel cell power generation system 40 includes a fuel cell 41, a fifth DCDC converter 42, a second DC bus 43, a second inverter 44, a sixth DCDC converter 45, a heater 46, a hot water storage unit 47, and a controller 51. It has a low-voltage power supply 52 and an auxiliary power supply 55.
  • the auxiliary power supply 55 may be referred to as a D1 power supply 55.
  • the fuel cell 41 generates DC power.
  • the fuel cell 41 includes a stack. The stack then produces DC power from oxygen and hydrogen.
  • the fifth DCDC converter 42 converts the DC power generated by the fuel cell 41 into DC power having a different voltage.
  • the fifth DCDC converter 42 boosts the DC power generated by the fuel cell 41.
  • the boosted DC power is supplied to the second DC bus 43.
  • the second inverter 44 converts the DC power input from the second DC bus 43 into AC power having a voltage V AC2 .
  • the AC power obtained by the second inverter 44 is supplied to the main distribution board 80.
  • the sixth DCDC converter 45 converts the DC power input from the second DC bus 43 into DC power having a different voltage. In this example, the sixth DCDC converter 45 steps down the DC power input from the second DC bus 43.
  • the heater 46 uses direct current power converted by the sixth DC/DC converter 45 to warm water.
  • the warmed water (hereinafter sometimes referred to as hot water) is stored in the hot water storage unit 47.
  • the fuel cell power generation system 40 outputs all the power generated by the fuel cell 41 from the second inverter 44 when the power generated by the fuel cell 41 is larger than the required load at the output destination of the second inverter 44.
  • surplus power a part of the power output from the second inverter 44 that exceeds the required load (hereinafter, may be referred to as surplus power) is reversely flown to the system power supply 200.
  • the power is supplied from the second DC bus 43 to the heater 46 via the sixth DCDC converter 45. That is, the sixth DCDC converter 45 is for surplus power. Further, the heater 46 warms the water and prevents reverse power flow.
  • the controller 51 controls the DCDC converters 42 and 45, the second inverter 44, and a protection relay 62 described later.
  • the controller 51 is a micro control unit (MCU).
  • the low-voltage power supply 52 supplies control power to the controller 51, the protection relay 62, and the characteristic conversion circuit 100 described later.
  • the D1 power supply 55 is used to operate auxiliary equipment of the fuel cell power generation system 40, such as a pump, a blower, and a valve.
  • the substrate 60 is provided on the path connecting the fuel cell power generation system 40 and the power station 10. Direct current power is supplied to the substrate 60 from the fuel cell power generation system 40, specifically from the second DC bus 43.
  • the substrate 60 has a characteristic conversion circuit 100, an LC filter 61, and a protection relay 62.
  • the characteristic conversion circuit 100 is provided on the path connecting the fuel cell power generation system 40 and the DC power conversion device 20, more specifically, on the DC power path.
  • the characteristic conversion circuit 100 executes characteristic conversion control.
  • a DC power supply system including the fuel cell power generation system 40 and the characteristic conversion circuit 100 is configured, and DC power can be supplied from the DC power supply system to the DC power converter 20. This point is the same in the embodiments described later.
  • the characteristic conversion control brings about an output voltage-output power characteristic in which the output power of the characteristic conversion circuit 100 becomes maximum when the output voltage of the characteristic conversion circuit 100 has a certain value.
  • the DC power conversion device 20 is designed to be able to perform MPPT control on the solar power generation system that maximizes the output power when the output voltage is within the predetermined range.
  • the characteristic conversion control brings about an output voltage-output power characteristic in which the output power of the characteristic conversion circuit 100 becomes maximum when the output voltage of the characteristic conversion circuit 100 has a value within the predetermined range.
  • the output voltage-output current characteristic becomes smaller as the output voltage of the characteristic conversion circuit 100 increases. Bring Here, in the region where the output voltage of the characteristic conversion circuit 100 crosses the certain value, from the first value where the output voltage of the characteristic conversion circuit 100 is smaller than the certain value to the second value which is larger than the certain value. Area.
  • FIG. 3A An example of the above output voltage-output power characteristic and output voltage-output current characteristic is shown in FIG. 3A.
  • the output voltage-output power characteristic of the characteristic conversion circuit 100 is described as a VP characteristic.
  • the output voltage-output current characteristic of the characteristic conversion circuit 100 is described as VI characteristic.
  • the solid line represents the VP characteristic.
  • the dotted line represents the VI characteristic.
  • the DC power converter 20 is designed to be able to execute MPPT control of the solar power generation system.
  • the characteristic conversion control of the characteristic conversion circuit 100 makes it possible to extract electric power from the fuel cell power generation system 40 to the DC power converter 20 by executing MPPT control using the DC power converter 20.
  • the characteristic conversion circuit 100 By appropriately adjusting the output voltage-output power characteristic by the characteristic conversion circuit 100, it is possible to prevent the output voltage of the characteristic conversion circuit 100 from becoming excessively large. Therefore, it is possible to prevent the DC power conversion device 20 from being damaged by the overvoltage input from the fuel cell power generation system 40 to the DC power conversion device 20.
  • the output voltage-output power characteristic of the characteristic conversion circuit 100 when the output voltage of the characteristic conversion circuit 100 reaches the above-mentioned value, the power transmitted from the characteristic conversion circuit 100 to the DC power conversion device 20 is The increase is stopped. Therefore, it is possible to prevent the electric power sent from the characteristic conversion circuit 100 to the DC power conversion device 20 from excessively increasing. It is possible to prevent the electric power sent from the fuel cell power generation system 40 to the characteristic conversion circuit 100 from excessively increasing. Therefore, it is possible to prevent the output current of the fuel cell power generation system 40 from excessively increasing as the output power of the fuel cell power generation system 40 increases. For this reason, it is possible to prevent the protection function from working and the power generation of the fuel cell 41 to be stopped, and the power supply from the fuel cell power generation system 40 to the DC power converter 20 to be stopped.
  • the characteristic conversion circuit 100 it is easy to extract a large amount of power from the fuel cell power generation system 40 to the DC power conversion device 20 based on the MPPT control.
  • this point will be described with reference to FIG. 3A as well as FIG. 3A.
  • the output voltage-output current becomes smaller as the output voltage of the characteristic conversion circuit 100 increases as the output voltage of the characteristic conversion circuit 100 increases in a region where the output voltage of the characteristic conversion circuit 100 exceeds the certain value. Bring characteristics. Due to this output voltage-output current characteristic, the graph of the output voltage-output power characteristic of the characteristic conversion circuit 100 has a curved shape in which the output power is convex upward with respect to the output voltage in the region where the output voltage crosses the certain value. obtain. In a typical example, the graph of the output voltage-output power characteristic of the characteristic conversion circuit 100 is a single peak graph in which the output power becomes maximum when the output voltage has the above-mentioned certain value.
  • the graph of the output voltage-output power characteristic of the characteristic conversion circuit 100 has a linear shape in which the output power is upward with respect to the output voltage, as shown in FIG. 3B.
  • the MPPT control is executed but the operating point is adjusted to a point deviating from the maximum power point.
  • the output voltage of the characteristic conversion circuit 100 is adjusted to the voltage V real deviated from the output voltage V target at the maximum power point.
  • the output power of the characteristic conversion circuit 100 decreases as compared with the case where the operating point is adjusted to the maximum power point.
  • this reduction width is described as ⁇ P B.
  • the output voltage-output power characteristic graph of the characteristic conversion circuit 100 is linear or curved, if the operating point deviates from the maximum power point, the output power of the characteristic conversion circuit 100 becomes Decrease. However, the amount of decrease is different. Specifically, the decrease width ⁇ P A in the case of FIG. 3A is smaller than the decrease width ⁇ P B of FIG. 3B. As described above, the fact that the graph of the output voltage-output power characteristic has a curved shape that is convex upward suppresses the reduction range of the output power due to the above-mentioned deviation, and allows the fuel cell power generation system 40 to transfer to the DC power converter 20. Therefore, it is advantageous from the viewpoint of suppressing the reduction range of the electric power taken out.
  • the user may purchase the characteristic conversion circuit 100 from one vendor and the DC power conversion device 20 that performs MPPT control from another vendor.
  • the characteristic conversion circuit 100 is connected to the DC power conversion device 20 having a performance unknown to the designer of the characteristic conversion circuit 100.
  • the operating point may be adjusted to a point deviating from the maximum power point because the characteristic conversion control and the MPPT control are not completely compatible. From this, it can be said that the fact that the graph of the output voltage-output power characteristic has a curved shape that is convex upward has an actual merit. It can also be said that the convex curve shape of the output voltage-output power characteristic graph improves the compatibility of the characteristic conversion circuit 100 and reduces the restrictions of the DC power conversion device 20 that can be adopted.
  • the output current of the characteristic conversion circuit 100 increases as the output voltage of the characteristic conversion circuit 100 increases in a region where the output voltage of the characteristic conversion circuit 100 is larger than 0 and smaller than the certain value.
  • the output voltage-output current characteristic may be reduced.
  • the output current of the characteristic conversion circuit 100 becomes smaller as the output voltage of the characteristic conversion circuit 100 becomes larger in the region where the output voltage of the characteristic conversion circuit 100 is larger than the certain value and smaller than the open circuit voltage. It may provide a voltage-output current characteristic.
  • the open circuit voltage is the output voltage of the characteristic conversion circuit 100 when the output current of the characteristic conversion circuit 100 is zero.
  • the output characteristics have both an area where the output voltage is larger than the first value and smaller than the certain value and an area where the output voltage is larger than the certain value and smaller than the second value.
  • the output current linearly decreases as the output voltage increases. That is, the output characteristic is a characteristic in which the output current decreases in the form of a linear function with respect to the output voltage in both of the above regions.
  • the output characteristic can be a characteristic in which the output power changes in the form of a quadratic function with respect to the output voltage in both of the above regions.
  • the output characteristics are such that the output voltage is in both the region where the output voltage is larger than 0 and smaller than the certain value and the region where the output voltage is from the certain value to the open circuit voltage value.
  • the characteristic is that the output current becomes linearly smaller as becomes larger. That is, the output characteristic is a characteristic in which the output current decreases in the form of a linear function with respect to the output voltage in both of the above regions.
  • the output characteristic can be a characteristic in which the output power changes in the form of a quadratic function with respect to the output voltage in both of the above regions.
  • the point where the voltage is zero and the power is zero is defined as the origin.
  • the maximum power point can be said to be the point where the voltage has the above-mentioned value and the power is maximum.
  • the point where the voltage is the open circuit voltage and the power is zero is defined as the open circuit voltage point.
  • the straight line connecting the origin and the maximum power point is defined as the first straight line.
  • the straight line connecting the maximum power point and the open circuit voltage point is defined as the second straight line.
  • a region where the output voltage in the graph of the output voltage-output power characteristic is larger than the first value and smaller than the certain value is on the higher power side than the first straight line.
  • a region where the output voltage in the graph of the output voltage-output power characteristic is larger than the certain value and smaller than the second value is on the higher power side than the second straight line.
  • a region where the output voltage in the graph of the output voltage-output power characteristics is larger than 0 and smaller than the above certain value is on the higher power side than the first straight line.
  • the region where the output voltage is from the certain value to the open circuit voltage is on the higher power side than the second straight line.
  • the above-described predetermined range includes an actual machine reference range that is within ⁇ 20 V of the output voltage of the photovoltaic power generation system 31 or 32 when the output power of the photovoltaic power generation system 31 or 32 reaches a peak. Then, the characteristic conversion control adjusts the output voltage at the maximum power point of the characteristic conversion circuit 100 to a value within the actual machine reference range. If the photovoltaic system 31 or 32 used in the power system 300 is known, the power system 300 can be designed so that MPPT control for the photovoltaic system can be implemented. That is, the above-mentioned predetermined range can be set so as to include the actual machine reference range. Furthermore, the characteristic conversion circuit 100 can be designed so that the output voltage at the maximum power point of the characteristic conversion circuit 100 is adjusted to a value within the actual machine reference range. The power system 300 of this example is advantageous from the viewpoint of ease of design.
  • the characteristic conversion control is executed based on the electric output of the characteristic conversion circuit 100.
  • the electric output is the output voltage and output current of the characteristic conversion circuit 100.
  • the characteristic conversion control includes the first feedback control and the second feedback control.
  • the first feedback control is control performed when the output current of the characteristic conversion circuit 100 is relatively small.
  • the second feedback control is control performed when the output current of the characteristic conversion circuit 100 is relatively large.
  • the first feedback control is performed when the output current of the characteristic conversion circuit 100 is relatively small and the output voltage is relatively large.
  • the output current of the characteristic conversion circuit 100 decreases as the output voltage of the characteristic conversion circuit 100 increases.
  • the first feedback control reduces the output power of the characteristic conversion circuit 100 as the output voltage of the characteristic conversion circuit 100 increases.
  • the second feedback control is performed when the output current of the characteristic conversion circuit 100 is relatively large and the output voltage is relatively small.
  • the second feedback control reduces the output current of the characteristic conversion circuit 100 as the output voltage of the characteristic conversion circuit 100 increases.
  • the second feedback control increases the output power of the characteristic conversion circuit 100 as the output voltage of the characteristic conversion circuit 100 increases.
  • the output voltage-output power characteristic and the output voltage-output current characteristic can be realized.
  • the alternate long and short dash line represents the contribution of the first feedback control.
  • the chain double-dashed line represents the contribution of the second feedback control.
  • the characteristic conversion circuit has the following features; in the first feedback control, the ratio of the decrease in the output current to the increase in the output voltage in the output voltage-output current characteristic is larger than that in the second feedback control, and/or the second feedback control. It may have a feature that the ratio of the decrease of the output voltage to the increase of the output current in the output voltage-output current characteristic is smaller than that of the control. With this configuration, the output characteristic of the characteristic conversion circuit 100 can easily approach the output characteristic of the photovoltaic power generation system. Note that this feature is a concept including a mode in which the output voltage does not change even when the output current changes in the first feedback control, as shown in FIGS. 18 and 19 described later.
  • the ratio of the decrease in the output current to the increase in the output voltage in the output voltage-output current characteristic is larger than that in the second feedback control. Further, in the example of FIG. 3A, in the first feedback control, the ratio of the decrease in the output voltage to the increase in the output current in the output voltage-output current characteristic is smaller than that in the second feedback control.
  • the open circuit voltage of the characteristic conversion circuit 100 is controlled by the first feedback control.
  • the DC power conversion device 20 has a first DCDC converter 21, a second DCDC converter 22 and a third DCDC converter 23.
  • the first DCDC converter 21 changes the output voltage of the characteristic conversion circuit 100 by MPPT control.
  • the second DCDC converter 22 changes the output voltage of the first photovoltaic power generation system 31 by MPPT control.
  • the third DCDC converter 23 changes the output voltage of the second solar power generation system 32 by MPPT control.
  • the multi-string type DC power conversion device 20 that individually controls the photovoltaic power generation systems 31 and 32 and the characteristic conversion circuit 100 by MPPT is realized.
  • the DC power converter may be a centralized type that collectively performs MPPT control.
  • FIG. 4 shows an example of the characteristic conversion circuit 100.
  • the characteristic conversion circuit 100 of FIG. 4 includes a voltage/current control circuit 160, a first feedback circuit 110, a second feedback circuit 120, and a feedback current supply unit 130.
  • the first feedback circuit 110 has a first resistor 111, a second resistor 112, a third resistor 113, a first shunt regulator 115, and a current sensor 128.
  • the second feedback circuit 120 has a fourth resistor 121, a fifth resistor 122, a sixth resistor 123, a second shunt regulator 125, and a current sensor 128.
  • the current sensor 128 is shared by the first feedback circuit 110 and the second feedback circuit 120.
  • the feedback current supply unit 130 has a current supply power supply 131 and a seventh resistor 132. In the present embodiment, the current supply power source 131 is a constant voltage source.
  • the current sensor 128 detects the output current of the characteristic conversion circuit 100.
  • the current sensor 128 outputs a sensor output indicating the result of the detection.
  • the current sensor 128 outputs a larger sensor output as the output current of the characteristic conversion circuit 100 increases. That is, the sensor output increases as the output current of the characteristic conversion circuit 100 increases.
  • Such a current sensor 128 can be realized by using a shunt resistor, for example.
  • the sensor output output from the current sensor 128 is supplied to the connection point ps. Specifically, the sensor output is the sensor voltage V s .
  • the current sensor 128 also includes a sensor output unit 128a that outputs the sensor voltage V s .
  • FIG. 5 shows a current sensor 128 according to a specific example.
  • the current sensor 128 includes a shunt resistor 128r and a current sense amplifier 128s.
  • the resistance value of the shunt resistor 128r is R sense .
  • the current sense amplifier 128s outputs the total voltage of the voltage obtained by multiplying the voltage R sense I load by the gain G and the bias voltage V bias as the sensor voltage V s . That is, the sensor voltage V s generated by the current sensor 128 of the present embodiment is given by Equation 1.
  • V s R sense *I load *G+V bias
  • the output voltage V out of the characteristic conversion circuit 100 is divided by the first resistor 111 and the second resistor 112.
  • the sensor voltage V s is divided by the third resistor 113 and the second resistor 112.
  • a voltage obtained by adding these two divided voltages appears at the connection point p1 of the three resistors 111, 112, and 113.
  • the voltage appearing at the first connection point p1 may be referred to as a first reference voltage V ref1 .
  • the first reference voltage V ref1 is input to the first reference voltage terminal of the first shunt regulator 115.
  • the first current i1 is a current flowing downward in the first shunt regulator 115 in the drawing.
  • the output voltage V out of the characteristic conversion circuit 100 is divided by the fourth resistor 121 and the fifth resistor 122.
  • the sensor voltage V s is divided by the sixth resistor 123 and the fifth resistor 122.
  • a voltage obtained by adding these two divided voltages appears at the connection point p2 of the three resistors 121, 122 and 123.
  • the voltage appearing at the second connection point p2 may be referred to as the second reference voltage V ref2 .
  • the second reference voltage V ref2 is input to the second reference voltage terminal of the second shunt regulator 125.
  • the second current i2 is a current flowing downward in the second shunt regulator 125 in the drawing.
  • the characteristic conversion circuit 100 performs the characteristic conversion by the first feedback circuit 110 in the region where the output current of the characteristic conversion circuit 100 is small, and by the second feedback circuit 120 in the region where the output current of the characteristic conversion circuit 100 is large. ..
  • the parameters of the resistors 111, 112, 113, 121, 122 and 123 and the shunt regulators 115 and 125 are selected so that the circuits 110 and 120 operate as described above.
  • the output characteristic of the characteristic conversion circuit 100 is determined by the analog circuit included in the characteristic conversion circuit 100.
  • the output characteristic can be considered as a relationship among the output current, the output voltage, and the output power.
  • the output characteristic of the characteristic conversion circuit 100 is determined by the circuit constant of the analog circuit included in the characteristic conversion circuit 100.
  • the circuit constant refers to the resistance value of the resistor or the like.
  • the voltage/current control circuit 160 is a DCDC converter.
  • the voltage/current control circuit 160 reduces the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 as the current flowing out from the current supply power source 131 is larger. As described above, in the characteristic conversion circuit 100, the ratio is adjusted according to the current flowing out from the current supply power source 131.
  • Such a characteristic conversion circuit 100 can be designed as appropriate.
  • the first shunt regulator 115 of this embodiment will be further described with reference to FIG. 6.
  • the first shunt regulator 115 includes a first reference voltage terminal 115a, a first cathode 115K, a first anode 115A, a first reference voltage source 115s, a first operational amplifier 115o, and a first transistor 115t.
  • the first operational amplifier 115o includes a non-inverting amplification terminal 115oa, an inverting amplification terminal 115ob, and an output terminal 115oc.
  • the first transistor 115t includes a cathode side terminal 115ta, an anode side terminal 115tb, and a control terminal 115tc.
  • the voltage input to the first reference voltage terminal 115a is supplied to the non-inverting amplification terminal 115a.
  • Voltage of the inverting amplifier terminal 115 Rushb is the first reference voltage source 115s, is set to a high voltage by the first reference voltage V s1 than the voltage of the first anode 115A.
  • the first current i1 flows from the first cathode 115K to the first anode 115A through the cathode side terminal 115ta and the anode side terminal 115tb in this order.
  • the first transistor 115t is a bipolar transistor, specifically an NPN transistor.
  • the cathode side terminal 115ta is a collector.
  • the anode side terminal 115tb is an emitter.
  • the control terminal 115tc is the base. In this description, the current flowing between the output terminal 115c and the control terminal 115tc, specifically the base current, is ignored because it is sufficiently small.
  • the operation of the first feedback circuit 110 can be described as follows.
  • the first reference voltage V ref1 increases.
  • the first shunt regulator 125 the greater the deviation from the first reference voltage V s1 of the first reference voltage V ref1 by the first reference voltage V ref1 is increased, the first current i1 increases.
  • the first current i1 increases.
  • the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 decreases. In this way, the first feedback circuit 110 controls the output voltage V out of the characteristic conversion circuit 100. Specifically, the first feedback circuit 110 adjusts the transformation ratio of the characteristic conversion circuit 100 so that the first reference voltage V ref1 follows the first reference voltage V s1 .
  • the current sensor 128 makes the first connection via the connection point ps and the third resistor 113 in this order.
  • the current flowing at the point p1 becomes large.
  • the first shunt regulator 115 causes the first reference voltage V ref1 to follow the constant first reference voltage V s1 .
  • a constant current flows through the second resistor 112. This means that when the current flowing through the third resistor 113 toward the first connection point p1 increases, the current flowing through the first resistor 111 toward the first connection point p1 decreases. When this current decreases, the voltage generated in the first resistor 111 decreases.
  • the second shunt regulator 125 of this embodiment will be further described with reference to FIG. 7.
  • the second shunt regulator 125 includes a second reference voltage terminal 125a, a second cathode 125K, a second anode 125A, a second reference voltage source 125s, a second operational amplifier 125o, and a second transistor 125t.
  • the second operational amplifier 125 nie includes a non-inverting amplifier terminal 125egaa, an inverting amplifier terminal 125 Cincinnatib, and an output terminal 125 Moderatorc.
  • the second transistor 125t includes a cathode side terminal 125ta, an anode side terminal 125tb, and a control terminal 125tc.
  • the voltage input to the second reference voltage terminal 125a is supplied to the non-inverting amplification terminal 125a.
  • Voltage of the inverting amplifier terminal 125 Brightonb is the second reference voltage source 125s, is set to a high voltage by the second reference voltage V s2 than the voltage of the second anode 125A.
  • the second transistor 125t is a bipolar transistor, specifically, an NPN transistor.
  • the cathode side terminal 125ta is a collector.
  • the anode side terminal 125tb is an emitter.
  • the control terminal 125tc is the base. In this description, the current flowing between the output terminal 125c and the control terminal 125tc, specifically the base current, is neglected as being sufficiently small.
  • the operation of the second feedback circuit 120 can be described as follows. If the output voltage V out of the characteristic conversion circuit 100 increases, or if the output current of the characteristic conversion circuit 100 increases and the sensor voltage V s increases, the second reference voltage V ref2 increases. In the second shunt regulator 125, the greater the deviation from the second reference voltage V s2 of the second reference voltage V ref2 by the second reference voltage V ref2 is increased, the second current i2 is large. When the second current i2 increases, the current flowing out of the current supply power source 131 also increases. When this outflow current increases, the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 decreases. In this way, the second feedback circuit 120 controls the output voltage V out of the characteristic conversion circuit 100. Specifically, the second feedback circuit 120 adjusts the transformation ratio of the characteristic conversion circuit 100 so that the second reference voltage V ref2 follows the second reference voltage V s2 .
  • the current sensor 128 makes the second connection via the connection point ps and the sixth resistor 123 in this order.
  • the current flowing at the point p2 becomes large.
  • the second shunt regulator 125 causes the second reference voltage V ref2 to follow the constant second reference voltage V s2 .
  • a constant current flows through the fifth resistor 122. This means that when the current flowing through the sixth resistor 123 toward the second connection point p2 increases, the current flowing through the fourth resistor 121 toward the second connection point p2 decreases. When this current decreases, the voltage generated in the fourth resistor 121 decreases.
  • the characteristic conversion circuit 100 includes the current sensor 128, at least one voltage dividing resistor, and the voltage/current control circuit 160 that is a DCDC converter.
  • the characteristic conversion circuit 100 uses the current sensor 128 to reflect the output current of the characteristic conversion circuit 100 in the characteristic conversion control.
  • the characteristic conversion circuit 100 uses at least one voltage dividing resistor to reflect the output voltage of the characteristic conversion circuit 100 in the characteristic conversion control.
  • the characteristic conversion circuit 100 adjusts the transformation ratio of the voltage/current control circuit 160 by characteristic conversion control.
  • the at least one voltage dividing resistor includes a first voltage dividing resistor and a second voltage dividing resistor.
  • the first voltage dividing resistor includes a first resistor 111 and a second resistor 112.
  • the second voltage dividing resistor includes a fourth resistor 121 and a fifth resistor 122.
  • a voltage/current control circuit 160 that is a DCDC converter, a first feedback circuit 110 that performs first feedback control, and a second feedback circuit that performs second feedback control. 120 are provided.
  • the first feedback circuit 110 has a first shunt regulator 115 to which the first reference voltage V ref1 that changes according to the output current and the output voltage of the characteristic conversion circuit 100 is input.
  • the second feedback circuit 120 has a second shunt regulator 125 to which the second reference voltage V ref2 that changes according to the output current and the output voltage of the characteristic conversion circuit 100 is input.
  • the first shunt regulator 115 is used to adjust the transformation ratio of the voltage/current control circuit 160 so that the first reference voltage V ref1 is maintained constant.
  • the transformation ratio of the voltage/current control circuit 160 is adjusted by using the second shunt regulator 125 so that the second reference voltage V ref2 is maintained constant.
  • the first feedback circuit has a first voltage dividing resistor.
  • the second feedback circuit has a second voltage dividing resistor.
  • the first feedback circuit 110 and the second feedback circuit 120 share the current sensor 128.
  • the first voltage dividing resistor is used to reflect the output voltage of the characteristic conversion circuit 100 on the first reference voltage V ref1 .
  • the current sensor 128 is used to reflect the output current of the characteristic conversion circuit 100 in the first reference voltage V ref1 .
  • the second voltage dividing resistor is used to reflect the output voltage of the characteristic conversion circuit 100 on the second reference voltage V ref2 .
  • the current sensor 128 is used to reflect the output current of the characteristic conversion circuit 100 in the second reference voltage V ref2 .
  • the first voltage dividing resistor is composed of the first resistor 111 and the second resistor 112.
  • the second voltage dividing resistor includes a fourth resistor 121 and a fifth resistor 122.
  • the first feedback circuit has a third voltage dividing resistor.
  • the second feedback circuit has a fourth voltage dividing resistor.
  • the third voltage dividing resistor is used to reflect the output current of the characteristic conversion circuit 100 in the first reference voltage V ref1 .
  • the fourth voltage dividing resistor is used to reflect the output current of the characteristic conversion circuit 100 in the second reference voltage V ref2 .
  • the third voltage dividing resistor is composed of the third resistor 113 and the second resistor 112.
  • the fourth voltage dividing resistor includes a sixth resistor 123 and a fifth resistor 122.
  • the characteristic conversion circuit 100 has a feedback control loop in which the output current and the output voltage of the characteristic conversion circuit 100 are reflected in the output current and the output voltage of the characteristic conversion circuit 100 thereafter. Has been done.
  • the feedback control loop is configured using the feedback circuit 110 or 120.
  • the output power of the characteristic conversion circuit 100 is supplied to the DC power conversion device 20, specifically the first DCDC converter 21, via the LC filter 61 and the protection relay 62.
  • the power storage device 25 As described above, the power storage device 25 is supplied with power from the fourth DCDC converter 12. The power storage device 25 also supplies power to the fourth DCDC converter 12.
  • the power storage device 25 is, for example, a lithium battery. However, a battery other than a lithium battery may be used as the power storage device 25. A capacitor may be used as the power storage device 25.
  • the main distribution board 80 has an interconnection breaker 81, a main breaker 82, a secondary interconnection breaker 83, and a first branch portion 85.
  • the first branch part 85 includes a plurality of branch breakers.
  • the first branch portion 85 includes branch breakers 85a, 85b and 85c.
  • the main breaker 82 is connected to the system power supply 200 by an upstream electric line 88.
  • the upstream electric circuit 88 is connected to the downstream electric circuit 89 via the main breaker 82.
  • a secondary interconnection breaker 83 is connected to the downstream electric circuit 89.
  • the secondary interconnection breaker 83 is provided on the path connecting the main breaker 82 and the second inverter 44.
  • the secondary interconnection breaker 83 is electrically connected to the first branch portion 85.
  • the first branch 85 is also connected to the downstream electric circuit 89.
  • the branch breaker 85a of the first branch section 85 is provided on the path connecting the main breaker 82 and the system power input section 28a of the power switching unit 28.
  • the branch breaker 85b is provided on the path connecting the main breaker 82 and the second load 252.
  • the branch breaker 85c is provided on the path connecting the main breaker 82 and the third load 253.
  • the upstream electric circuit 88 has a third connection point p3.
  • the interconnection breaker 81 is provided on the path connecting the third connection point p3 and the first inverter 13.
  • AC power of voltage V AC2 can be supplied from the system power supply 200 to the main breaker 82 via the third connection point p3.
  • AC power of voltage V AC2 can be supplied from the system power supply 200 to the first inverter 13 via the third connection point p3 and the interconnection breaker 81 in this order.
  • AC power of voltage V AC2 can be reversely flowed to the system power supply 200 via the interconnection breaker 81 and the third connection point p3 in this order.
  • AC power of voltage V AC2 can be supplied from the first inverter 13 to the main breaker 82 via the interconnection breaker 81 and the third connection point p3 in this order.
  • the secondary interconnection breaker 83 can be supplied with the AC power of the voltage V AC2 from the second inverter 44.
  • AC power of voltage V AC1 can be supplied to the power switching unit 28 from the branch breaker 85a.
  • AC power having the voltage V AC1 may be supplied from the branch breaker 85b to the second load 252.
  • AC power of voltage V AC2 can be supplied from the branch breaker 85c to the third load 253.
  • the power switching unit 28 has a plurality of input parts and a power output part 28c.
  • the plurality of input units include a system power input unit 28a and an independent power input unit 28b.
  • the power switching unit 28 switches which of the plurality of input units is connected to the power output unit 28c.
  • the power switching unit 28 switches which of the system power input unit 28a and the self-sustained power input unit 28b is connected to the power output unit 28c.
  • the power switching unit 28 thus selectively connects one of the first inverter 13 and the branch breaker 85a to the self-sustained distribution board 90, specifically to the main breaker 92.
  • the self-sustained distribution board 90 has a main breaker 92 and a second branching portion 95.
  • the second branch section 95 includes a plurality of branch breakers.
  • the second branch portion 95 includes branch breakers 95a, 95b and 95c.
  • the main breaker 92 is connected to the power switching unit 28 by an upstream electric circuit 98.
  • the upstream electric circuit 98 is connected to the downstream electric circuit 99 via the main breaker 92.
  • the second branch 95 is connected to the downstream electric circuit 99.
  • the branch breaker 95a of the second branch section 95 is provided on the path connecting the main breaker 92 and the D1 power source 55.
  • the branch breaker 95b is provided on the path connecting the main breaker 92 and the hot water storage unit 47.
  • the branch breaker 95c is provided on the path connecting the main breaker 92 and the first load 251.
  • the AC power of the voltage V AC1 can be supplied from the power switching unit 28 to the downstream electric circuit 99 via the main breaker 92.
  • AC power having a voltage V AC1 can be supplied from the branch breaker 95a to the D1 power supply 55.
  • AC power having a voltage V AC1 can be supplied from the branch breaker 95b to the hot water storage unit 47.
  • AC power having the voltage V AC1 may be supplied from the branch breaker 95c to the first load 251 through the outlet 260.
  • the protection relay 62 is open based on the disconnection command from the controller 51.
  • the open state refers to a state in which a current is prohibited from flowing through itself.
  • the power switching unit 28 connects the branch breaker 85a and the self-sustained distribution board 90.
  • Electric power generated by the fuel cell 41 is supplied to the second DC bus 43 via the fifth DCDC converter 42. Part or all of the electric power supplied to the second DC bus 43 is supplied to the secondary interconnection breaker 83 via the second inverter 44.
  • a part of the electric power supplied to the secondary interconnection breaker 83 is supplied to the main breaker 92 via the branch breaker 85a and the electric power switching unit 28 in this order.
  • a part of the electric power supplied to the main breaker 92 is supplied to the D1 power supply 55 via the branch breaker 95a.
  • Another part of the electric power supplied to the main breaker 92 is supplied to the hot water storage unit 47 via the branch breaker 95b.
  • Another part of the electric power supplied to the main breaker 92 is supplied to the first load 251 via the branch breaker 95c and the outlet 260 in this order.
  • Another part of the electric power supplied to the secondary interconnection breaker 83 is supplied to the second load 252 via the branch breaker 85b. Another part of the electric power supplied to the secondary interconnection breaker 83 is supplied to the third load 253 via the branch breaker 85c.
  • the power is supplied from the second DC bus 43 to the heater 46 via the sixth DCDC converter 45.
  • the DC power converter 20, specifically, the second DCDC converter 22 extracts power from the first photovoltaic power generation system 31 by MPPT control, and supplies the extracted power to the first DC bus 11.
  • the DC power conversion device 20, specifically, the third DCDC converter 23 extracts power from the second solar power generation system 32 by MPPT control, and supplies the extracted power to the first DC bus 11.
  • the power storage device 25 When the power storage device 25 is not in a fully charged state, a part of the electric power supplied to the first DC bus 11 is supplied to the power storage device 25, and the rest of the power is supplied to the first inverter 13. When the power storage device 25 is fully charged, all the electric power supplied to the first DC bus 11 is supplied to the first inverter 13. The power supplied to the first inverter 13 is supplied to the interconnection breaker 81.
  • the power supplied from the second inverter 44 to the secondary interconnection breaker 83 is at least the amount of the above-mentioned margin, and the loads 251 to 253 and D1.
  • the power supply 55 and the hot water storage unit 47 are configured to be insufficient with respect to the total required load. Electric power corresponding to this shortage is supplied from the interconnection breaker 81 to the downstream electric circuit 89 via the main breaker 82, and together with the electric power supplied from the second inverter 44 to the secondary interconnection breaker 83, It is supplied to the one-branching unit 85.
  • the balance of the electric power supplied to the interconnection breaker 81 flows backward to the system power supply 200.
  • the above-mentioned shortage of power is supplied from the system power supply 200 to the downstream side electric line 89 via the main breaker 82, and the second inverter 44 supplies two power. It is supplied to the first branch section 85 together with the electric power supplied to the next interconnection breaker 83. If the power storage device 25 is not fully charged and the power generation by the photovoltaic power generation systems 31 and 32 is insufficient to charge the power storage device 25, the system power supply 200, the first inverter 13, the first DC bus 11 Electric power is supplied to the power storage device 25 via the fourth DCDC converter 12.
  • the protection relay 62 is in the closed state based on the parallel command from the controller 51.
  • the closed state refers to a state in which a current is allowed to flow through itself.
  • the power switching unit 28 connects the first inverter 13 and the self-sustained distribution board 90.
  • Electric power generated by the fuel cell 41 is supplied to the second DC bus 43 via the DCDC converter 42. Part or all of the DC power supplied to the second DC bus 43 is supplied to the characteristic conversion circuit 100.
  • the first DCDC converter 21 extracts power from the characteristic conversion circuit 100 (strictly, via the LC filter 61) by MPPT control, and supplies the extracted power to the first DC bus 11. To do.
  • the DC power conversion device 20 takes out electric power from the solar power generation systems 31 and 32 and supplies the taken out electric power to the first DC bus 11 as in the grid interconnection.
  • the electric power which is made to follow the required load or brought close thereto is supplied from the first DC bus 11 to the main breaker 92 via the first inverter 13 and the electric power switching unit 28.
  • the electric power supplied to the main breaker 92 is supplied to the D1 power source 55, the hot water storage unit 47, and the first load 251 as in the system interconnection.
  • power system 300 includes power storage device 25.
  • the solar power generation systems 31 and 32, the DC power conversion device 20, and the power storage device 25 are connected in this order.
  • the fuel cell power generation system 40, the characteristic conversion circuit 100, the DC power conversion device 20, and the power storage device 25 are connected in this order. Therefore, the power storage device 25 can be charged not only from the solar power generation systems 31 and 32 but also from the fuel cell power generation system 40.
  • the power system 300 includes a power storage device 25, an inverter 13 that converts DC power into AC power, and an outlet 260.
  • the photovoltaic power generation systems 31 and 32, the DC power converter 20, the inverter 13, and the outlet 260 are connected in this order.
  • the fuel cell power generation system 40, the characteristic conversion circuit 100, the DC power conversion device 20, the inverter 13, and the outlet 260 are connected in this order.
  • Power storage device 25, inverter 13, and outlet 260 are connected in this order. Therefore, in this example, power can be supplied from the fuel cell power generation system 40 to the outlet 260 supplied with power from the solar power generation systems 31 and 32 and the power storage device 25. This is convenient during a power failure for the following reasons.
  • the solar power generation systems 31 and 32 cannot generate power at night or in rainy weather. If power cannot be supplied from the fuel cell power generation system 40 to the outlet 260, the period during which power can be taken out of the outlet 260 is limited based on only the power storage device 25 when power failure continues, such as at night or in rainy weather. Become. On the other hand, in this example, since the electric power can be supplied from the fuel cell power generation system 40 to the outlet 260, the above period can be extended. It is convenient for the user to be able to take out the electric power from one outlet for a long time without being replaced with another outlet when the power failure continues at night or in the rain.
  • the hot water storage unit 47 is also connected to the outlet 260 in the same manner as the above. Therefore, in the event of a power outage that continues at night or in the case of rain, the hot water storage unit 47 can be supplied with the power required for its operation for a long time.
  • the power system 300 is configured to be able to supply power from the power storage device 25 to the fuel cell power generation system 40 (specifically, to the D1 power supply 55). Specifically, the same connection as the above connection to the outlet 260 is also made to the D1 power supply 55. In this way, the dedicated power supply for starting the fuel cell power generation system 40 at the time of power failure can be omitted.
  • the dedicated power source is typically a power source for supplying power to the auxiliary equipment of the fuel cell power generation system 40.
  • characteristic conversion circuit 100X which is a specific example of the characteristic conversion circuit 100, will be described with reference to FIG.
  • the elements already described with reference to FIG. 4 are denoted by the same reference numerals, and the description thereof may be omitted.
  • a LLC converter is configured in the characteristic conversion circuit 100X.
  • the LLC converter is configured such that the higher the current flowing from the current supply power source 131, the higher the oscillation frequency is defined, and the higher the oscillation frequency, the smaller the ratio of the output voltage to the input voltage of the characteristic conversion circuit 100X.
  • the characteristic conversion circuit 100X is provided with a first feedback circuit 110, a second feedback circuit 120, a feedback current supply unit 130X, a current resonance control unit 140, and a voltage/current control circuit 160X.
  • the voltage/current control circuit 160X constitutes the LLC converter.
  • the feedback current supply unit 130X has a first light emitting diode 135 in addition to the current supply power source 131 and the seventh resistor 132. The current flowing from the current supply power source 131 flows through the first light emitting diode 135.
  • the current resonance control unit 140 has an eighth resistor 141, a first capacitor 142, a ninth resistor 143, a first phototransistor 145, and a control IC 146.
  • the eighth resistor 141, the first capacitor 142, and the combination of the ninth resistor 143 and the first phototransistor 145 are connected in parallel with each other.
  • the first phototransistor 145 cooperates with the first light emitting diode 135 to form the first photocoupler 150.
  • the control IC 146 includes a constant current source 147, a feedback terminal 148, a high side driver output terminal 149a, and a low side driver output terminal 149b.
  • a period during which the first capacitor 142 is charged with electric charge (hereinafter, may be referred to as a charging period) and a period during which electric charge is discharged from the first capacitor 142 (hereinafter, referred to as a discharging period). There are) and alternate.
  • the discharging period and the charging period are switched based on the voltage of the feedback terminal 148.
  • the constant current source 147 charges the first capacitor 142 via the feedback terminal 148.
  • the voltage of the feedback terminal 148 rises.
  • the discharge period is switched.
  • charging of the electric charge from the constant current source 147 to the first capacitor 142 is stopped.
  • the electric charge charged in the first capacitor 142 is discharged through the eighth resistor 141.
  • the electric charge is further discharged through the ninth resistor 143 and the first phototransistor 145.
  • the voltage of the feedback terminal 148 decreases.
  • the charging period is switched.
  • the charge/discharge frequency corresponds to the above oscillation frequency.
  • a drive signal is output from the high side driver output terminal 149a.
  • a drive signal is output from the low side driver output terminal 149b.
  • a drive signal is output from the high side driver output terminal 149a.
  • a drive signal is output from the low side driver output terminal 149b.
  • the voltage/current control circuit 160X includes a second capacitor 161, a first switching element 162a, a second switching element 162b, a third capacitor 163a, a fourth capacitor 163b, a fifth capacitor 164, a transformer 165, and It has one diode 166a, a second diode 166b, and a sixth capacitor 167.
  • the switching elements 162a and 162b are connected in series to form a series circuit.
  • the second capacitor 161 is connected in parallel to this series circuit.
  • the third capacitor 163a is connected in parallel to the first switching element 162a.
  • the fourth capacitor 163b is connected in parallel to the second switching element 162b.
  • the switching elements 162a and 162b are MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors).
  • the fifth capacitor 164 is a resonance capacitor.
  • the transformer 165 has a first winding 165a which is a primary winding, and a second winding 165b and a third winding 165c which are secondary windings.
  • a current outflow terminal of the first switching element 162a and a current inflow terminal of the second switching element 162b are connected to one end of the first winding 165a.
  • the fifth capacitor 164 is connected between the other end of the first winding 165a and the current outflow terminal of the second switching element 162b.
  • the current outflow terminal is the source terminal.
  • the current inflow terminal is the drain terminal.
  • the anode of the first diode 166a is connected to one end of the second winding 165b.
  • One end of the sixth capacitor 167 and the cathode of the second diode 166b are connected to the cathode of the first diode 166a.
  • the other end of the sixth capacitor 167 and the reference potential are connected to the other end of the second winding 165b.
  • the other end of the sixth capacitor 167 and the reference potential are connected to one end of the third winding 165c.
  • the anode of the second diode 166b is connected to the other end of the third winding 165c.
  • a drive pulse signal is supplied to the control terminal of the first switching element 162a from the high side driver output terminal 149a.
  • a drive pulse signal is supplied to the control terminal of the second switching element 162b from the low side driver output terminal 149b.
  • the switching elements 162a and 162b are alternately turned on/off by being supplied with drive pulse signals having opposite phases.
  • the control terminal is a gate terminal.
  • FIG. 9 shows another example of the characteristic conversion circuit.
  • the same parts as those in the example of FIG. 4 are denoted by the same reference numerals, and description thereof may be omitted.
  • a feedback current supply section 195 is provided instead of the feedback current supply section 130 of the characteristic conversion circuit 100 in FIG.
  • the feedback current supply unit 195 has a tenth resistor 191 in addition to the current supply power source 131 and the seventh resistor 132.
  • the characteristic conversion circuit 190 like the characteristic conversion circuit 100, the larger the voltage input to the first reference voltage terminal of the first shunt regulator 115, the more the current supply power supply 131, the seventh resistor 132, the first shunt regulator 115, and the reference. The current flowing through the potential in this order, that is, the first current increases.
  • the characteristic conversion circuit 190 unlike the characteristic conversion circuit 100, the larger the voltage input to the second reference voltage terminal of the second shunt regulator 125, the more the current supply power supply 131, the tenth resistor 191, and the second shunt regulator 125. The current flowing through the reference potential in this order, that is, the second current increases.
  • the second current i2 becomes substantially zero, and the current flowing out from the current supply power source 131 is substantially the first current i1.
  • the first current i1 becomes substantially zero, and the current flowing out from the current supply power source 131 is substantially the second current i2. That is, it can be said that the first feedback circuit 110 performs the characteristic conversion in the region where the output current of the characteristic conversion circuit 190 is small, and the second feedback circuit 120 performs the characteristic conversion in the region where the output current of the characteristic conversion circuit 190 is large. .. In these respects, the characteristic conversion circuit 190 is common to the characteristic conversion circuit 100. Therefore, in the characteristic conversion circuit 190, as in the characteristic conversion circuit 100, the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 is adjusted.
  • FIG. 10 shows a characteristic conversion circuit 190X which is a specific example of the characteristic conversion circuit 190.
  • the same parts as those in the example of FIG. 8 are denoted by the same reference numerals, and description thereof may be omitted.
  • a feedback current supply section 195X is provided instead of the feedback current supply section 130X of the characteristic conversion circuit 100X in FIG.
  • a current resonance control section 199 is provided instead of the current resonance control section 140 of the characteristic conversion circuit 100X.
  • the feedback current supply unit 195X has a tenth resistor 191 and a second light emitting diode 192 in addition to the current supply power source 131, the seventh resistor 132 and the first light emitting diode 135.
  • the current resonance control unit 199 includes an eighth resistor 141, a first capacitor 142, a ninth resistor 143, a first phototransistor 145, and a control IC 146, as well as an eleventh resistor 196 and a second phototransistor 197.
  • the combination of the eighth resistor 141, the first capacitor 142, the ninth resistor 143 and the first phototransistor 145, and the combination of the eleventh resistor 196 and the second phototransistor 197 are connected in parallel with each other.
  • the second light emitting diode 192 and the second phototransistor 197 cooperate with each other to form a second photocoupler 198.
  • a period in which the first capacitor 142 is charged (hereinafter, also referred to as a charging period) and a period in which the first capacitor 142 is discharged. (Hereinafter, may be referred to as a discharge period) alternately.
  • the constant current source 147 charges the first capacitor 142 via the feedback terminal 148.
  • the voltage of the feedback terminal 148 rises.
  • the discharge period is switched.
  • charging of the electric charge from the constant current source 147 to the first capacitor 142 is stopped.
  • the electric charge charged in the first capacitor 142 is discharged through the eighth resistor 141.
  • the electric charge is further discharged through the ninth resistor 143 and the first phototransistor 145 or the eleventh resistor 196 and the second phototransistor 197.
  • the voltage of the feedback terminal 148 decreases.
  • the charging period is switched.
  • the charge state of the electric charge of the first capacitor 142 in the current resonance control unit 199 changes as in the current resonance control unit 140. Therefore, in the characteristic conversion circuit 190X, as in the characteristic conversion circuit 100X, the ratio of the output voltage to the input voltage of the voltage/current control circuit 160X is adjusted.
  • the specific example of the characteristic conversion circuit 100 of FIG. 4 is not limited to the characteristic conversion circuit 100X of FIG.
  • the configurations of the first feedback circuit 110 and the second feedback circuit 120 of FIGS. 4 and 8 are not essential.
  • the first feedback circuit 410 has a current sensor 128 and a regulator 170.
  • the second feedback circuit 420 has a current sensor 128 and a regulator 170.
  • the current sensor 128 and the regulator 170 are shared by the first feedback circuit 410 and the second feedback circuit 420.
  • the current sensor 128 detects the output current of the characteristic conversion circuit 400.
  • the current sensor 128 outputs a sensor output indicating the result of the detection.
  • the current sensor 128 outputs a larger sensor output as the output current of the characteristic conversion circuit 400 increases. That is, the sensor output increases as the output current of the characteristic conversion circuit 400 increases.
  • the sensor output is specifically the sensor voltage V s .
  • the current sensor 128 includes a sensor output unit 128a that outputs the sensor voltage V s .
  • the sensor voltage V s output by the current sensor 128 may be referred to as the first sensor voltage V s .
  • the adjuster 170 is configured to adjust a variable parameter.
  • the variable parameter may be manually adjustable or automatically adjustable.
  • the regulator 170 regulates the first sensor voltage V s input to the regulator 170 to the second sensor voltage V M.
  • the regulator 170 is a DCDC converter that transforms the first sensor voltage V s .
  • the variable parameter is a parameter that changes the transformation ratio of the DCDC converter.
  • the adjuster 170 has the configuration shown in FIG.
  • the regulator 170 in FIG. 12 includes a voltage dividing circuit 170a and an amplifier circuit 170b.
  • the variable parameter is a parameter included in the voltage dividing circuit 170a or the amplifier circuit 170b.
  • the sensor output unit 128a, the voltage dividing circuit 170a, the amplifier circuit 170b, and the connection point ps are connected in this order.
  • the voltage dividing circuit 170a includes a resistor FR1, a resistor FR2, and a variable resistor VR1.
  • the sensor output unit 128a, the resistor FR1, the resistor FR2, the variable resistor VR1 and the reference potential are connected in this order.
  • the voltage dividing circuit 170a divides the first sensor voltage V s by using the resistors FR1, FR2 and VR1.
  • the divided voltage V D shown in the following Equation 2 is generated.
  • FR1 is the resistance value of the resistor FR1.
  • FR1 is the resistance value of the resistor FR2.
  • VR1 is the resistance value of the variable resistor VR1.
  • "*" is a symbol representing multiplication.
  • Formula 2: V D V s *(FR2+VR1)/(FR1+FR2+VR1)
  • the amplifier circuit 170b includes a resistor FR3, a resistor FR4, and an operational amplifier 175.
  • the operational amplifier 175 includes a first input terminal 175a, a second input terminal 175b, and an output terminal 175c.
  • the divided voltage V D is input to the first input terminal 175a.
  • the second input terminal 175b is connected to the output terminal 175c via the resistor FR3.
  • the second input terminal 175b is connected to the reference potential via the resistor FR4. Further, the output terminal 175c, the resistor FR3, the resistor FR4, and the reference potential are connected in this order.
  • the amplifier circuit 170b generates the second sensor voltage V M based on the divided voltage V D , and outputs the second sensor voltage V M from the output terminal 175c.
  • the second sensor voltage V M is given by Equation 3 below.
  • FR3 is the resistance value of the resistor FR3.
  • FR4 is the resistance value of the resistor FR4.
  • V M V D
  • the first input terminal 175a is a non-inverting amplifier terminal.
  • the second input terminal 175b is an inverting amplification terminal.
  • the second sensor voltage V M is supplied to the connection point ps. After that, the voltage at the connection point ps is used in the same manner as in the first embodiment.
  • the voltage dividing circuit 170a includes a variable resistor VR1.
  • the variable parameter is the resistance value of the variable resistor VR1.
  • the resistor FR1 or the resistor FR2 may be a variable resistor. Even in this case, the divided voltage V D and the second sensor voltage V M can be adjusted by adjusting the resistance value of the variable resistor.
  • variable resistor may be included in the amplifier circuit 170b instead of the voltage divider circuit 170a.
  • the resistor FR3 or the resistor FR4 may be a variable resistor. Even in this case, the second sensor voltage V M can be adjusted by adjusting the resistance value of the variable resistor.
  • the sensor outputs are relative so that the output voltage-output power characteristic (i) and the output current-output power characteristic (ii) described below are provided.
  • the first feedback control is executed, and when the sensor output is relatively large, the second feedback control is executed.
  • the sensor output is specifically the first sensor voltage V s .
  • the output voltage-output power characteristic of (i) is an output voltage-output power characteristic in which the output power of the characteristic conversion circuit 400 becomes maximum when the output voltage of the characteristic conversion circuit 400 has a certain value.
  • the output current-output power characteristic (ii) is an output current-output power characteristic in which the output power of the characteristic conversion circuit 400 is maximum when the output current of the characteristic conversion circuit 400 is the switching current isw .
  • the switching current isw is the output current of the characteristic conversion circuit 400 when the first feedback control and the second feedback control are switched.
  • the above-mentioned certain value is specifically a value within a predetermined range, as in the first embodiment.
  • the switching current isw depends on the error in the detection of the output current of the characteristic conversion circuit 400 by the current sensor 128 and changes when the variable parameter is changed.
  • the switching current isw may deviate from a target value (hereinafter, may be referred to as a target current). If the switching current isw shifts, the maximum power point may deviate from the target point. If the maximum power point shifts, the maximum power of the characteristic conversion circuit 400 may deviate from a target value (hereinafter, sometimes referred to as target power).
  • the switching current isw can be adjusted by changing the variable parameter. This makes it possible to reduce the deviation of the switching current isw from the target current, decrease the deviation of the maximum power point from the target point, and decrease the deviation of the maximum power from the target power. Further, it is also possible to adjust the maximum power of the characteristic conversion circuit 400 according to the situation by adjusting the variable current and adjusting the switching current isw . For example, when the generated power of the photovoltaic power generation system connected to the DC power converter 20 is small, the maximum power may be increased, and when the generated power of the photovoltaic power generation system is large, the maximum power may be decreased. it can.
  • the maximum output power of the fuel cell power generation system 40 may decrease due to, for example, aging deterioration of the stack of the fuel cell 41. In such a case, by reducing the maximum power output from the characteristic conversion circuit 400, the maximum power can be kept within a range that the fuel cell power generation system 40 can supply.
  • the extracted power can be adjusted to a value according to the situation. For example, when the generated power of the photovoltaic power generation system connected to the DC power converter 20 is small, the extracted power is increased, and when the generated power of the photovoltaic power generation system is large, the extracted power is reduced. You can Further, when the maximum output power of the fuel cell power generation system 40 decreases, the extracted power can be reduced.
  • the current sensor 128 may have individual variations. The effect of individual variation will be described in detail with reference to FIGS. 13 to 15.
  • the current sensor 128 has the configuration shown in FIG.
  • the resistance value R sense of the shunt resistor 128r, the gain G, and the bias voltage V bias are ideally reference values. However, the resistance value R sense , the gain G, and/or the bias voltage V bias may have an error in the tolerance range.
  • the current sensor 128 outputs a larger first sensor voltage V1 when the resistance value of the shunt resistor 128r is larger than the reference value, compared to when the resistance value of the shunt resistor 128r is the reference value. It is configured.
  • the current sensor 128 is configured to output a larger first sensor voltage V1 when the gain G is larger than the reference value, compared to when the gain G is the reference value.
  • FIG. 13 shows the output characteristic of the characteristic conversion circuit 400 when the bias voltage V bias is changed when the resistance value R sense and the gain G are at the reference values.
  • “output voltage (0) of characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the bias voltage V bias is a reference value.
  • the “output voltage (A) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the bias voltage V bias is 101% of the reference value.
  • the “output voltage (B) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the bias voltage V bias is 99% of the reference value.
  • the “output voltage (C) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the bias voltage V bias is 102% of the reference value.
  • the “output voltage (D) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the bias voltage V bias is 98% of the reference value.
  • the “output power (0) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the bias voltage V bias is a reference value.
  • the “output power (A) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the bias voltage V bias is 101% of the reference value.
  • the “output power (B) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the bias voltage V bias is 99% of the reference value.
  • the “output power (C) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the bias voltage V bias is 102% of the reference value.
  • the “output power (D) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the bias voltage V bias is 98% of the reference value.
  • switching current isw (C) indicates the switching current isw when the bias voltage Vbias is a reference value.
  • switching current isw (A) indicates the switching current isw when the bias voltage V bias is 101% of the reference value.
  • switching current isw (B) indicates the switching current isw when the bias voltage Vbias is 99% of the reference value.
  • switching current isw (C) indicates the switching current isw when the bias voltage Vbias is 102% of the reference value.
  • Switching current isw (D) indicates the switching current isw when the bias voltage Vbias is 98% of the reference value. As described above, the switching current isw is the output current of the characteristic conversion circuit 400 when the first feedback control and the second feedback control are switched.
  • the switching current isw matches the target current.
  • the switching current isw is smaller than when the bias voltage V bias is at the reference value.
  • the switching current i sw is larger than when the bias voltage V bias is at the reference value.
  • the maximum power of the characteristic conversion circuit 400 matches the target power.
  • the bias voltage V bias is larger than the reference value, the maximum power is smaller than when the bias voltage V bias is at the reference value.
  • the bias voltage V bias is smaller than the reference value, the maximum power is larger than when the bias voltage V bias is at the reference value.
  • the maximum electric power can be adjusted by adjusting the resistance value of the variable resistor VR1 to adjust the switching current isw of the characteristic conversion circuit 400.
  • the switching current i sw and the maximum power are reduced by adjusting the resistance value of the variable resistor VR1 to increase the second sensor voltage V M as compared with the case where the bias voltage V bias is at the reference value.
  • the switching current isw and the maximum power can be brought close to the target current and the target power.
  • the switching current isw and the maximum power can be brought close to the target current and the target power.
  • the switching current i sw and the maximum power are increased by adjusting the resistance value of the variable resistor VR1 to reduce the second sensor voltage V M as compared with the case where the bias voltage V bias is at the reference value.
  • the switching current isw and the maximum power can be brought close to the target current and the target power.
  • the switching current isw and the maximum power can be brought close to the target current and the target power.
  • the switching current i sw and the maximum power can be brought close to the values when the bias voltage V bias is at the reference value. That is, the switching current isw and the maximum power can be brought close to the target current and the target power.
  • the output characteristic of the characteristic conversion circuit 400 can be brought close to that when the bias voltage V bias is at the reference value.
  • the switching current isw of the characteristic conversion circuit 400 can be adjusted by adjusting the resistance value of the variable resistor VR1, and the maximum power can be adjusted. ..
  • the horizontal axis represents the output current of the characteristic conversion circuit 400.
  • 14 and 15 show the output characteristics of the characteristic conversion circuit 400 when the gain G and the bias voltage V bias are changed when the resistance value R sense of the shunt resistor 128r is at the reference value.
  • “output voltage (0) of characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the gain G and the bias voltage V bias are reference values.
  • the “output voltage (E) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the gain G is 101% of the reference value and the bias voltage V bias is 102% of the reference value.
  • the “output voltage (F) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the gain G is 99% of the reference value and the bias voltage V bias is 98% of the reference value.
  • the “output power (0) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G and the bias voltage V bias are reference values.
  • the “output power (E) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G is 101% of the reference value and the bias voltage V bias is 102% of the reference value.
  • the “output power (F) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G is 99% of the reference value and the bias voltage V bias is 98% of the reference value.
  • “Switching current isw (0)” indicates the switching current isw when the gain G and the bias voltage Vbias are reference values.
  • Switchching current i sw (E)” is when the gain G is 101% of the reference value and the bias voltage V bias is 102% of the reference value, indicating the switching current i sw.
  • Switchching current i sw (F) is when the gain G is 99% of the reference value and the bias voltage V bias is 98% of the reference value, indicating the switching current i sw.
  • output voltage (0) of characteristic conversion circuit indicates an output voltage of the characteristic conversion circuit 400 when the gain G and the bias voltage V bias are reference values.
  • the “output voltage (G) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the gain G is 99% of the reference value and the bias voltage V bias is 102% of the reference value.
  • the “output voltage (H) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the gain G is 101% of the reference value and the bias voltage V bias is 98% of the reference value.
  • the “output power (0) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G and the bias voltage V bias are reference values.
  • the “output power (G) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G is 99% of the reference value and the bias voltage V bias is 102% of the reference value.
  • the “output power (H) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G is 101% of the reference value and the bias voltage V bias is 98% of the reference value.
  • Switchching current isw (0) indicates the switching current isw when the gain G and the bias voltage Vbias are reference values.
  • Switchching current i sw (G) is when the gain G is 99% of the reference value and the bias voltage V bias is 102% of the reference value, indicating the switching current i sw.
  • Switchching current i sw (H) is obtained when the gain G is 101% of the reference value and the bias voltage V bias is 98% of the reference value, indicating the switching current i sw.
  • the switching current isw fluctuates as the gain G and the bias voltage Vbias fluctuate.
  • the switching current isw and the maximum power can be brought close to the target current and the target power by adjusting the resistance value of the variable resistor VR1.
  • the output characteristic of the characteristic conversion circuit 400 can be brought close to that when the gain G and the bias voltage V bias are at the reference values.
  • the switching current isw and the maximum power can be brought close to the target current and the target power by adjusting the resistance value of the variable resistor VR1.
  • the technique of the second embodiment is applicable not only to the configuration of FIG. 4 of the first embodiment but also to the configurations of FIGS. 8 to 10.
  • the adjuster 170 is also applicable to the configurations of FIGS. 8 to 10.
  • FIG. 16 and 17 are block diagrams of a power system 500 according to the third embodiment. Specifically, FIG. 16 shows an example of the flow of electric power during grid interconnection. FIG. 17 shows an example of the flow of electric power at the time of power failure.
  • the power system 500 has a board 560.
  • the substrate 560 is provided on the path connecting the fuel cell power generation system 40 and the power station 10. Direct current power is supplied to the substrate 560 from the fuel cell power generation system 40, specifically from the second DC bus 43.
  • the substrate 560 has a characteristic conversion circuit 600, an LC filter 61, and a protection relay 62.
  • the characteristic conversion circuit 600 is provided on the path connecting the fuel cell power generation system 40 and the DC power conversion device 20, specifically, on the path of DC power.
  • the characteristic conversion circuit 600 executes characteristic conversion control.
  • FIG. 18 and 19 show the output characteristics of the characteristic conversion circuit 600.
  • FIG. 20 shows an example of the characteristic conversion circuit 600.
  • the characteristic conversion control performed by the characteristic conversion circuit 600 is performed by the output voltage-output power characteristic in which the output power of the characteristic conversion circuit 600 becomes maximum when the output voltage of the characteristic conversion circuit 600 has a certain value.
  • Bring The characteristic conversion control includes first feedback control and second feedback control.
  • the first feedback control is control performed when the output current of the characteristic conversion circuit 600 is relatively small.
  • the second feedback control is control performed when the output current of the characteristic conversion circuit 600 is relatively large.
  • the characteristic conversion circuit 600 includes a voltage/current control circuit 160, a current sensor 128, and a regulator 180.
  • the voltage/current control circuit 160 is a DCDC converter.
  • the voltage/current control circuit 160 is provided between the fuel cell power generation system 40 and the current sensor 128.
  • the voltage/current control circuit 160 is provided between the second DC bus 43 and the current sensor 128.
  • the current sensor 128 detects the output current of the characteristic conversion circuit 600.
  • the current sensor 128 outputs a sensor output indicating the result of the detection.
  • the current sensor 128 outputs a larger sensor output as the output current of the characteristic conversion circuit 600 increases. That is, the sensor output increases as the output current of the characteristic conversion circuit 600 increases.
  • the sensor output is the first sensor voltage V1.
  • the current sensor 128 includes a sensor output unit 128a that outputs the first sensor voltage V1.
  • the first sensor voltage V1 corresponds to the sensor voltage V s of the first embodiment.
  • the adjuster 180 is configured to be able to adjust variable parameters.
  • the regulator 180 is a variable output power supply and the variable parameter is a variable output.
  • the regulator 180 which is a variable output power supply may be described as the variable output power supply 180.
  • the variable output power supply 180 outputs a variable output.
  • the variable output is the variable voltage V4.
  • the variable output power supply 180 is, for example, a digital-analog port of the controller 51.
  • the characteristic conversion circuit 600 is provided with a first circuit 610 and a second circuit 620.
  • the first circuit 610 executes the first feedback control in which the output power of the characteristic conversion circuit 600 increases as the sensor output increases.
  • the second circuit 620 cooperates with the first circuit 610 to execute the second feedback control in which the output power of the characteristic conversion circuit 600 decreases as the sensor output increases.
  • a feedback current supply unit 130 is also provided in the characteristic conversion circuit 600.
  • the first circuit 610, the second circuit 620, and the voltage/current control circuit 160 cooperate to execute the characteristic conversion control.
  • the first circuit 610 executes the first feedback control in cooperation with the voltage/current control circuit 160.
  • the second circuit executes the second feedback control in cooperation with the first circuit 610 and the voltage/current control circuit 160.
  • the first feedback control is performed when the sensor output is relatively small so that the output voltage-output power characteristic of (i) and the output current-output power characteristic of (ii) described below are provided. Is executed and the second feedback control is executed when the sensor output is relatively large.
  • the output voltage-output power characteristic of (i) is the output voltage-output power characteristic in which the output power of the characteristic conversion circuit 600 becomes maximum when the output voltage of the characteristic conversion circuit 600 has a certain value as shown in FIG. Is.
  • the above-mentioned certain value is specifically a value within a predetermined range, as in the first embodiment.
  • the DC power conversion device 20 is designed to be able to execute the MPPT control of the solar power generation system that maximizes the output power when the output voltage is within the predetermined range.
  • the characteristic conversion circuit 600 has the output voltage-output power characteristic of (i) above in which the output power becomes maximum when the output voltage has a value within the predetermined range.
  • the output voltage-output power characteristic of the fuel cell power generation system is not necessarily suitable for power extraction by MPPT control.
  • the characteristic conversion circuit 600 having the output voltage-output power characteristic of the above (i) outputs power from the fuel cell power generation system 40 to the DC power converter 20 by executing the MPPT control using the DC power converter 20. Allow to take out.
  • the output current-output power characteristic of (ii) is the output current-output at which the output power of the characteristic conversion circuit 600 becomes maximum when the output current of the characteristic conversion circuit 600 is the switching current i sw as shown in FIG. It is a power characteristic.
  • the switching current isw is the output current of the characteristic conversion circuit 600 when the first feedback control and the second feedback control are switched.
  • the switching current isw depends on the error in the detection of the output current of the characteristic conversion circuit 600 by the current sensor 128 and changes when the variable parameter is changed.
  • the variable parameter is a variable output in this embodiment, and is specifically the variable voltage V4.
  • the switching current isw may deviate from a target value (hereinafter, may be referred to as a target current). If the switching current isw shifts, the maximum power point shown in FIGS. 18 and 19 may deviate from the target point. If the maximum power point shifts, the maximum power of the characteristic conversion circuit 600 may deviate from a target value (hereinafter, sometimes referred to as target power).
  • the switching current isw can be adjusted by changing the variable parameter. This makes it possible to reduce the deviation of the switching current isw from the target current, decrease the deviation of the maximum power point from the target point, and decrease the deviation of the maximum power from the target power. Further, by adjusting the variable parameter to adjust the switching current isw , it is possible to adjust the maximum power of the characteristic conversion circuit 600 according to the situation. For example, when the generated power of the photovoltaic power generation system connected to the DC power converter 20 is small, the maximum power may be increased, and when the generated power of the photovoltaic power generation system is large, the maximum power may be decreased. it can.
  • the maximum output power of the fuel cell power generation system 40 may decrease due to, for example, aging deterioration of the stack of the fuel cell 41. In such a case, by reducing the maximum electric power output from the characteristic conversion circuit 600, the maximum electric power can be kept within a range that the fuel cell power generation system 40 can supply.
  • the extracted power can be adjusted to a value according to the situation. For example, when the generated power of the photovoltaic power generation system connected to the DC power converter 20 is small, the extracted power is increased, and when the generated power of the photovoltaic power generation system is large, the extracted power is reduced. You can Further, when the maximum output power of the fuel cell power generation system 40 decreases, the extracted power can be reduced.
  • the characteristic conversion circuit 600 output voltage-output power characteristic is a characteristic in which the output power has a single peak with respect to the output voltage.
  • the output voltage-output power characteristic of the above (i) shows such a characteristic.
  • the output characteristics of the characteristic conversion circuit 600 will be further described.
  • the solid line represents the relationship between the output voltage of the characteristic conversion circuit 600 and the output power of the characteristic conversion circuit 600, that is, the output voltage-output power characteristic.
  • the short broken line represents the relationship between the output voltage of the characteristic conversion circuit 600 and the output current of the characteristic conversion circuit 600, that is, the output voltage-output current characteristic.
  • the alternate long and short dash line represents the contribution of the first feedback control.
  • the chain double-dashed line represents the contribution of the second feedback control.
  • the long dashed line represents the first sensor voltage V1.
  • the output voltage-output current characteristic of the characteristic conversion circuit 600 becomes such that the output voltage follows the specified value in the region where the output current is small, by the first feedback control. ..
  • the output voltage-output current characteristic of the characteristic conversion circuit 600 is such that the output voltage decreases as the output current increases in the region where the output current is large.
  • the output voltage-output current characteristic of the characteristic conversion circuit 600 is as shown by the short broken line in FIG.
  • the output voltage-output power characteristic of the characteristic conversion circuit 600 has a single peak and is convex as shown by the solid line in FIG.
  • the output voltage-output power characteristic that is convex on the characteristic conversion circuit 600 enables the MPPT control by the DC power conversion device 20.
  • the MPPT control of the characteristic conversion circuit 600 can be executed by the DC power conversion device 20.
  • the configuration of the characteristic conversion circuit 600 will be further described.
  • the first circuit 610 has a first resistor 621, a second resistor 622, and a first shunt regulator 625.
  • the second circuit 620 includes a current sensor 128, a sensor voltage adjustment circuit 620a, and a voltage/current conversion circuit 620b.
  • the feedback current supply unit 130 has a current supply power supply 131 and a third resistor 132.
  • the current supply power source 131 is a constant voltage source.
  • the third resistor 132 of the third embodiment corresponds to the seventh resistor 132 of the first embodiment.
  • the voltage/current control circuit 160 increases the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 as the current flowing out from the current supply power source 131 is smaller. As described above, in the characteristic conversion circuit 600, the ratio is adjusted according to the current flowing out from the current supply power source 131.
  • the output voltage of the characteristic conversion circuit 600 is divided by the first resistor 621 and the second resistor 622.
  • the divided voltage appears at the first connection point p1 of the resistors 621 and 622.
  • the voltage appearing at the first connection point p1 may be referred to as a first reference voltage V ref1 .
  • the first reference voltage V ref1 is input to the first reference voltage terminal 625a of the first shunt regulator 625.
  • the larger the first reference voltage V ref1 input to the first reference voltage terminal 625a the larger the current i1 flowing through the current supply power supply 131, the third resistor 132, the first shunt regulator 625 and the reference potential in this order.
  • the current i1 is a current flowing downward in the first shunt regulator 625.
  • the current i1 may be referred to as the first current i1.
  • the open circuit voltage of the characteristic conversion circuit 600 is controlled by the first feedback control.
  • the open circuit voltage is the output voltage of the characteristic conversion circuit 600 when the output current of the characteristic conversion circuit 600 is zero.
  • the operation of the first shunt regulator 625 and the voltage/current control circuit 160 causes the first reference voltage V ref1 to follow a later-described first reference voltage V s1 so that the open circuit voltage is regulated. Set to the value.
  • the first shunt regulator 625 of this embodiment will be further described with reference to FIG.
  • the first shunt regulator 625 includes a first reference voltage terminal 625a, a first cathode 625K, a first anode 625A, a first reference voltage source 625s, a first operational amplifier 625o, and a first transistor 625t.
  • the first operational amplifier 625 additionally includes a non-inverting amplifier terminal 625egaa, an inverting amplifier terminal 625egab, and an output terminal 625 réellec.
  • the first transistor 625t includes a cathode side terminal 625ta, an anode side terminal 625tb, and a control terminal 625tc.
  • the voltage input to the first reference voltage terminal 625a is supplied to the non-inverting amplification terminal 625a.
  • Voltage of the inverting amplifier terminal 625 réelleb is the first reference voltage source 625S, is set to a high voltage by the first reference voltage V s1 than the voltage of the first anode 625A.
  • the first transistor 625t is a bipolar transistor, specifically, an NPN transistor.
  • the cathode side terminal 625ta is a collector.
  • the anode side terminal 625tb is an emitter.
  • the control terminal 625tc is the base. In this description, the current flowing between the output terminal 625c and the control terminal 625tc, specifically the base current, is ignored because it is sufficiently small.
  • the operation of the first circuit 610 can be described as follows. As the output voltage V out of the characteristic conversion circuit 600 increases, the first reference voltage V ref1 increases. In the first shunt regulator 625, the greater the deviation from the first reference voltage V s1 of the first reference voltage V ref1 by the first reference voltage V ref1 is increased, the first current i1 increases. As the first current i1 increases, the current flowing out of the current supply power source 131 also increases. When this outflow current increases, the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 decreases. In this way, the first circuit 610 cooperates with the voltage/current control circuit 160 to control the output voltage V out of the characteristic conversion circuit 600. Specifically, the first circuit 610 cooperates with the voltage/current control circuit 160 to cause the first reference voltage V ref1 to follow the first reference voltage V s1 , and defines the output voltage V out of the characteristic conversion circuit 600.
  • the sensor voltage adjustment circuit 620a of the second circuit 620 includes a variable output power supply 180, an input resistor R1, a feedback resistor R2, and a sensor voltage adjustment operational amplifier 124.
  • the current sensor 128 outputs the first sensor voltage V1.
  • the variable output power supply 180 outputs a variable voltage V4.
  • the sensor voltage adjustment circuit 620a generates a second sensor voltage V2 that changes according to the first sensor voltage V1 and the variable voltage V4.
  • the switching current isw deviates from the target current
  • the maximum power point deviates from the target point
  • the maximum power of the characteristic conversion circuit 600 deviates from the target power. There is a risk of slipping.
  • the deviation of the switching current i sw from the target current is reduced, and the maximum power point is less than the target point.
  • the deviation of the maximum power from the target power can be reduced. Further, it is also possible to adjust the maximum electric power of the characteristic conversion circuit 600 according to the situation by adjusting the variable voltage V4 and the switching current isw .
  • the sensor voltage adjustment operational amplifier 124 includes a sensor input terminal 124a, a variable voltage input terminal 124b, and a second sensor voltage output terminal 124c.
  • the sensor input terminal 124a is connected to the sensor output unit 128a via the input resistor R1.
  • the variable voltage V4 is input to the variable voltage input terminal 124b.
  • the second sensor voltage output terminal 124c is connected to the sensor input terminal 124a via the feedback resistor R2.
  • the sensor voltage adjustment operational amplifier 124 generates the second sensor voltage V2 based on the voltage difference between the sensor input terminal 124a and the variable voltage input terminal 124b, and outputs the second sensor voltage V2 from the second sensor voltage output terminal 124c.
  • the sensor input terminal 124a is an inverting amplification terminal.
  • the variable voltage input terminal 124b is a non-inverting amplifier terminal.
  • the voltage/current conversion circuit 620b of the second circuit 620 includes a voltage supply power source 129, an intervening resistor R3, a transistor driving operational amplifier 126, and an adjustment current output transistor 127.
  • the voltage supply power source 129 outputs the threshold voltage V3.
  • the voltage supply power source 129 is a constant voltage source.
  • the adjusted current i3 starts to flow.
  • the first feedback control is switched to the second feedback control.
  • the characteristic conversion circuit 600 whose control is switched at the timing when the current starts to flow is easy to design.
  • the transistor drive operational amplifier 126 includes a power supply input terminal 126a, a second sensor voltage input terminal 126b, and a control voltage output terminal 126c.
  • the power supply input terminal 126a is connected to the voltage supply power supply 129 via the intervening resistor R3.
  • the second sensor voltage V2 is input to the second sensor voltage input terminal 126b.
  • the transistor drive operational amplifier 126 generates the control voltage V c based on the voltage difference between the power supply input terminal 126 a and the second sensor voltage input terminal 126 b, and outputs the control voltage V c from the control voltage output terminal 126 c .
  • the power supply input terminal 126a is an inverting amplification terminal.
  • the second sensor voltage input terminal 126b is a non-inverting amplification terminal.
  • the adjusted current output transistor 127 includes a control terminal 127c, a first terminal 127a, and a second terminal 127b.
  • the control voltage V c is input to the control terminal 127c.
  • the first terminal 127a is connected to the voltage supply power source 129 via the intervening resistor R3.
  • the second terminal 127b outputs the adjusted current i3.
  • the adjusted current output transistor 127 is a bipolar transistor, specifically, a PNP transistor.
  • the control terminal 127c is a base.
  • the first terminal 127a is an emitter.
  • the second terminal 127b is a collector.
  • the first sensor voltage V1, the second sensor voltage V2, the adjustment current i3, and the output voltage Vout of the second circuit 620 will be further described using mathematical expressions.
  • FIG. 22 shows the current sensor 128 of this embodiment.
  • the current sensor 128 includes a shunt resistor 128r and a current sense amplifier 128s.
  • the resistance value of the shunt resistor 128r is R sense .
  • the current sense amplifier 128s outputs the total voltage of the voltage obtained by multiplying the voltage R sense I load by the gain G and the bias voltage V bias as the first sensor voltage V1. That is, the first sensor voltage V1 generated by the current sensor 128 of the present embodiment is given by Equation 4.
  • the current sensor 1208 may be used as the current sensor 128, and the output of the current sensor may be used as the first sensor voltage V1.
  • the current I load corresponds to the output current of the characteristic conversion circuit 600.
  • "*" is a symbol representing multiplication.
  • the second sensor voltage V2 is generated by the differential amplification using the sensor voltage adjustment operational amplifier 124.
  • the second sensor voltage V2 is given by Equation 5 below.
  • R1 is the resistance value of the input resistor R1.
  • R2 is the resistance value of the feedback resistor R2.
  • V2 V4+(V4-V1)*R2/R1
  • the transistor driving operational amplifier 126 sets the adjusted current output transistor 127 so that the voltage of the power supply input terminal 126a follows the voltage of the second sensor voltage input terminal 126b due to a virtual short when V2 ⁇ V3. Drive it. Specifically, in the transistor drive operational amplifier 126, when V2 ⁇ V3, the voltage of the power supply input terminal 126a becomes the second sensor voltage V2, and the voltage difference V3-V2 between the threshold voltage V3 and the second sensor voltage V2 causes the intervening resistance. The control terminal 127c is driven so that the current (V3-V2)/R3 is applied to R3 and flows from the intervening resistor R3 to the first terminal 127a.
  • Equation 6 the current flowing between the control voltage output terminal 126c and the control terminal 127c, the base current in the example of FIG. 20, is neglected because it is sufficiently small.
  • Formula 6: i3 (V3-V2)/R3
  • Formula 7: i3 0
  • the transistor drive operational amplifier 126 suppresses the change of the adjustment current i3 due to the change of the voltage between the terminals 127c-127a of the adjustment current output transistor 127 with temperature. Specifically, if the second sensor voltage V2 is directly supplied to the control terminal 127c of the transistor 127, the voltage of the first terminal 127a is the sum of the second sensor voltage V2 and the voltage between the terminals 127c-127a. Since the value becomes a value, it is affected by the voltage between the terminals 127c-127a.
  • the control terminal 127c is the base.
  • the first terminal 127a is an emitter.
  • the second terminal 127b is a collector.
  • the voltage between the terminals 127c-127a is the voltage between the base and the emitter.
  • the first shunt regulator 625 causes the first reference voltage V ref1 to follow the constant first reference voltage V s1 .
  • the output voltage V out is given by Equation 8 below.
  • R621 is the resistance value of the first resistor 621.
  • R622 is the resistance value of the second resistor 622.
  • Formula 8 indicates that the output voltage V out of the characteristic conversion circuit 600 decreases as the adjustment current i3 increases.
  • V out (V ref1 /R622-i3)*R621+V ref1
  • the adjustment current i3 acts to adjust the output voltage V out .
  • the adjustment current i3 can be referred to as the output voltage adjustment current i3.
  • the second feedback control is realized by adjusting the first feedback control. Specifically, this adjustment is performed by the second circuit 620.
  • the second circuit 620 can be referred to as an adjustment circuit.
  • the conversion of the output characteristics of the fuel cell power generation system 40 is performed using the first circuit 610 and the second circuit 620. It is often advantageous from the viewpoint of simplification of control configuration, cost, etc. that the circuit plays a role that software can play. Further, this makes it possible to avoid the software design and avoid the risk of software bugs.
  • the method of converting characteristics using a circuit is compatible with the fuel cell power generation system.
  • the output voltage and the output power of the fuel cell power generation system are easy to maintain constant unlike the wind power generation system and the like.
  • the output voltage and output power of the fuel cell power generation system are maintained constant at rated power generation. Therefore, when the power generation system connected to the characteristic conversion circuit is a fuel cell power generation system, it is not necessary to change the characteristic conversion characteristics according to the output voltage and/or the output power of the power generation system, and the circuit is used. It is easy to adopt a method that performs characteristic conversion.
  • the current sensor 128 may have individual variations. The influence of individual variation will be described in detail with reference to FIGS. 23 and 24.
  • the current sensor 128 has the configuration shown in FIG.
  • the resistance value R sense of the shunt resistor 128r, the gain G, and the bias voltage V bias are ideally reference values. However, the resistance value R sense , the gain G, and/or the bias voltage V bias may have an error in the tolerance range.
  • the current sensor 128 outputs a larger first sensor voltage V1 when the resistance value of the shunt resistor 128r is larger than the reference value, compared to when the resistance value of the shunt resistor 128r is the reference value. It is configured.
  • the current sensor 128 is configured to output a larger first sensor voltage V1 when the gain G is larger than the reference value, compared to when the gain G is the reference value.
  • FIG. 23 the horizontal axis represents the output voltage of the characteristic conversion circuit 600.
  • FIG. 23 shows the output characteristic of the characteristic conversion circuit 600 when the resistance value R sense is changed when the gain G and the bias voltage V bias are at the reference values.
  • output current (0) of characteristic conversion circuit indicates the output current of the characteristic conversion circuit 600 when the resistance value R sense of the shunt resistor 128r is at the reference value.
  • the “output current (+) of the characteristic conversion circuit” indicates the same output current when the resistance value R sense is larger than the reference value.
  • Output current ( ⁇ ) of characteristic conversion circuit” indicates the same output current when the resistance value R sense is smaller than the reference value.
  • Output power of characteristic conversion circuit (0)” indicates output power of the characteristic conversion circuit 600 when the resistance value R sense is at the reference value.
  • the “output power (+) of the characteristic conversion circuit” indicates the same output power when the resistance value R sense is larger than the reference value.
  • “Output power ( ⁇ ) of characteristic conversion circuit” indicates the same output power when the resistance value R sense is smaller than the reference value.
  • FIG. 24 shows the output characteristics of the characteristic conversion circuit 600 when the resistance value R sense is changed when the gain G and the bias voltage V bias are at the reference values.
  • output voltage (0) of characteristic conversion circuit indicates the output voltage of the characteristic conversion circuit 600 when the resistance value R sense of the shunt resistor 128r is at the reference value.
  • the “output voltage (+) of the characteristic conversion circuit” indicates the same output voltage when the resistance value R sense is larger than the reference value.
  • Output voltage ( ⁇ ) of characteristic conversion circuit” indicates the same output voltage when the resistance value R sense is smaller than the reference value.
  • Adjustment current i3(0) indicates the adjustment current i3 when the resistance value R sense of the shunt resistor 128r is at the reference value.
  • Adjustment current i3(+) indicates the adjustment current i3 when the resistance value R sense is larger than the reference value.
  • Adjustment current i3( ⁇ ) indicates the adjustment current i3 when the resistance value R sense is smaller than the reference value.
  • Output power of characteristic conversion circuit (0) indicates output power of the characteristic conversion circuit 600 when the resistance value R sense is at the reference value.
  • the “output power (+) of the characteristic conversion circuit” indicates the same output power when the resistance value R sense is larger than the reference value.
  • Output power ( ⁇ ) of characteristic conversion circuit” indicates the same output power when the resistance value R sense is smaller than the reference value.
  • Switchching current i sw (0) indicates the switching current i sw when the resistance value R sense is at the reference value.
  • switching current i sw (+) indicates the switching current i sw when the resistance value R sense is larger than the reference value.
  • switching current i sw ( ⁇ ) indicates the switching current i sw when the resistance value R sense is smaller than the reference value.
  • the switching current isw is the output current of the characteristic conversion circuit 600 when the first feedback control and the second feedback control are switched.
  • the switching current isw matches the target current. "Switching current isw (0)" corresponds to the target current.
  • the switching current isw is smaller than when the resistance value R sense is at the reference value.
  • the switching current i sw is larger than when the resistance value R sense is at the reference value.
  • the maximum power of the characteristic conversion circuit 600 matches the target power.
  • the “output power (0) of the characteristic conversion circuit” when the output current of the characteristic conversion circuit 600 is the “switching current i sw (0)” corresponds to the target power.
  • the maximum power is smaller than when the resistance value R sense is at the reference value.
  • the resistance value R sense is smaller than the reference value, the maximum power is larger than when the resistance value R sense is at the reference value.
  • the individual variation of the resistance value R sense of the shunt resistor 128r causes the variation of the maximum power point of the characteristic conversion circuit 600.
  • the variation of the maximum power point causes the variation of the switching current isw and the maximum power.
  • the switching current isw of the characteristic conversion circuit 600 can be adjusted and the maximum power can be adjusted.
  • the switching current isw and the maximum power can be reduced by reducing the variable voltage V4 as compared with the case where the resistance value R sense is at the reference value.
  • the switching current isw and the maximum power can be brought close to the target current and the target power.
  • the switching current i sw and the maximum power can be increased by increasing the variable voltage V4 as compared with the case where the resistance value R sense is at the reference value.
  • the switching current isw and the maximum power can be brought close to the target current and the target power.
  • the adjustment of the variable voltage V4 can change the adjustment current i3 and the maximum power.
  • the first sensor voltage V1 may have an error due to individual variations of the current sensor 128.
  • the second sensor voltage V2 is shown in FIG.
  • the voltage V2a is the second sensor voltage V2 before adjusting the variable voltage V4.
  • the variable voltage V4 before adjustment may or may not be 0V.
  • Expression 5 when the variable voltage V4 is increased, the second sensor voltage V2 is increased.
  • the voltage V2b is the second sensor voltage V2 after being increased in this way.
  • the variable voltage V4 when the variable voltage V4 is reduced, the second sensor voltage V2 is reduced.
  • the voltage V2c is the second sensor voltage V2 after being reduced in this way.
  • the arrow AR1 indicates that the second sensor voltage V2 can be adjusted by adjusting the variable voltage V4.
  • FIG. 25C shows the adjustment current i3 and the switching current isw .
  • the current i3a is the adjusted current i3 before adjusting the variable voltage V4 and the second sensor voltage V2.
  • the current i sw a is the switching current i sw at this time.
  • the current i3b is the adjusted current i3 after the timing at which the current starts to change in this way.
  • the current i sw b is the switching current i sw at this time.
  • the adjusted current i3 starts to flow when the output current of the characteristic conversion circuit 600 is smaller.
  • the current i3c is the adjusted current i3 after the timing at which the current starts to change in this way.
  • the current i sw c is the switching current i sw at this time.
  • the arrow AR2 indicates that the switching current isw can be adjusted by adjusting the variable voltage V4 and the second sensor voltage V2. By this adjustment, the maximum power is adjusted.
  • the switching current isw and the maximum power can be brought close to the values when the resistance value R sense is at the reference value. That is, the switching current isw and the maximum power can be brought close to the target current and the target power.
  • the variable voltage V4 is adjusted so that the output voltage becomes the target voltage and the output power becomes the maximum power and the target power when the output current is the target current. Calibrate.
  • the target current is the “switching current isw (0)” in FIG.
  • the target voltage is the “output voltage (0) of the characteristic conversion circuit” when the output current in FIG. 24 is the “switching current i sw (0)”.
  • the maximum power and the target power are the “output power (0) of the characteristic conversion circuit” when the output current in FIG. 24 is the “switching current i sw (0)”.
  • variable voltage V4 is adjusted as follows. First, direct current power is supplied from the fuel cell power generation system 40 to the characteristic conversion circuit 600 while causing the first DCDC converter 21 to perform constant current control so that the output current of the characteristic conversion circuit 600 is fixed to the target current. Next, the variable voltage V4 is adjusted so that the output voltage of the characteristic conversion circuit 600 becomes the target voltage.
  • the characteristic conversion circuit 600 has an output current-output voltage characteristic shown in “output voltage (+) of characteristic conversion circuit” of FIG.
  • the variable voltage V4 is increased.
  • the output current-output voltage characteristic changes, and the output voltage approaches the target voltage.
  • the switching current i sw matches the target current, and the output power becomes the maximum power and the target power.
  • the characteristic conversion circuit 600 has an output current-output voltage characteristic shown in “output voltage ( ⁇ ) of characteristic conversion circuit” of FIG.
  • the output current is the “switching current isw (0)”
  • the output voltage is the same as the target voltage.
  • the variable voltage V4 is reduced.
  • the output voltage starts to decrease from the target voltage.
  • variable voltage V4 is adjusted as follows. First, direct current power is supplied from the fuel cell power generation system 40 to the characteristic conversion circuit 600 while causing the first DCDC converter 21 to perform constant current control so that the output current of the characteristic conversion circuit 600 is fixed to the target current. Next, the variable voltage V4 is adjusted so that the output power of the characteristic conversion circuit 600 becomes the target power. The output power of the characteristic conversion circuit 600 can be measured using a power meter or the like.
  • the characteristic conversion circuit 600 has the output current-output power characteristic shown in “output power (+) of characteristic conversion circuit” in FIG.
  • the output power is lower than the target power when the output current is the “switching current isw (0)”. Therefore, the variable voltage V4 is increased. Then, the output current-output power characteristic changes, and the output power approaches the target power.
  • the output power can be the maximum power and the target power.
  • the switching current isw matches the target current, and the output voltage matches the target voltage.
  • the characteristic conversion circuit 600 has an output current-output power characteristic shown in “output power ( ⁇ ) of characteristic conversion circuit” of FIG.
  • the output current is the “switching current i sw (0)”
  • the output power is not the maximum power but is the same as the target power.
  • the variable voltage V4 is reduced.
  • the decrease width of the variable voltage V4 reaches a certain level, the output power starts to decrease from the target power.
  • the switching current isw can be made to match the target current and the output voltage can be made to match the target voltage while making the output power the maximum power and the target power. it can. Thereby, the above calibration is realized.
  • variable parameter is adjusted according to the power generation status of the photovoltaic power generation system connected to the DC power converter 20.
  • the variable parameter is adjusted according to the power generation status of the photovoltaic power generation system connected to the DC power converter 20.
  • the power system 500 of this embodiment includes a controller 51.
  • the fuel cell power generation system 40 includes a controller 51.
  • the controller 51 may not be included in the fuel cell power generation system 40.
  • the controller 51 changes the variable parameter according to the power generation output of at least one solar power generation system.
  • the output power of the characteristic conversion circuit 600 can be adjusted according to the power generation output of the solar power generation system.
  • the generated output is, for example, generated voltage, generated power, generated current, etc.
  • the power generation output of at least one photovoltaic power generation system may be the power generation output of one photovoltaic power generation system included in at least one photovoltaic power generation system, and a plurality of power generation outputs included in at least one photovoltaic power generation system may be included. It may be a value determined by the power generation output of the solar power generation system, or may be a value determined by the power generation output of all the solar power generation systems included in at least one solar power generation system. The value determined by the power output of a plurality or all of the photovoltaic power generation systems may be a total value or an average value.
  • the power generation output of at least one solar power generation system may be one power generation output of the solar power generation systems 31 and 32, and the total value or average of the power generation outputs of the solar power generation systems 31 and 32. It may be a value.
  • the power output is the power voltage of at least one photovoltaic system.
  • the controller 51 (a) changes the variable parameter so that the switching current isw becomes smaller when the power generation voltage increases over the threshold power generation voltage, or (b) switches as the power generation voltage increases.
  • the variable parameter is changed so that the current i sw becomes small.
  • the variable parameter is changed so that the switching current isw becomes small.
  • the maximum power of the characteristic conversion circuit 600 becomes small.
  • the power taken out from the characteristic conversion circuit 600 to the DC power conversion device 20 by the MPPT control becomes small. For the above reason, according to this specific example, it is possible to supply the DC power converter 20 with sufficient power.
  • the controller 51 changes a variable parameter using a control signal that represents a power generation output.
  • the control signal is generated by the DC power converter 20, for example.
  • power system 500 may include an output sensor that produces a control signal representative of the power output.
  • FIG. 26 shows a characteristic conversion circuit 600X which is a specific example of the characteristic conversion circuit 600.
  • the characteristic conversion circuit 600X can be configured by imitating the characteristic conversion circuit 100X of FIG. 8 of the first embodiment. Therefore, detailed description of the characteristic conversion circuit 600X will be omitted.
  • FIG. 27 and 28 are block diagrams of a power system 700 according to the fourth embodiment. Specifically, FIG. 27 shows an example of the flow of electric power during grid interconnection. FIG. 28 shows an example of the flow of electric power at the time of power failure.
  • the power system 700 has a board 760.
  • the substrate 760 is provided on the path connecting the fuel cell power generation system 40 and the power station 10. Direct current power is supplied to the substrate 760 from the fuel cell power generation system 40, specifically from the second DC bus 43.
  • the substrate 760 has a characteristic conversion circuit 800, an LC filter 61, and a protection relay 62.
  • the characteristic conversion circuit 800 is provided on the path connecting the fuel cell power generation system 40 and the DC power conversion device 20, specifically, on the path of DC power.
  • the characteristic conversion circuit 800 executes characteristic conversion control.
  • FIG. 29A and 30 show output characteristics of the characteristic conversion circuit 800 according to the fourth embodiment.
  • FIG. 31 shows a characteristic conversion circuit 800 according to the fourth embodiment.
  • the first circuit 810 executes the first feedback control in cooperation with the voltage/current control circuit 160.
  • the second circuit 820 executes the second feedback control in cooperation with the first circuit 810 and the voltage/current control circuit 160.
  • the current sensor 128 is used in both the first feedback control and the second feedback control.
  • the first feedback control is performed when the sensor output is relatively small so that the output voltage-output power characteristic of (i) and the output current-output power characteristic of (ii) described below are provided. Is executed and the second feedback control is executed when the sensor output is relatively large.
  • the output voltage-output power characteristic (i) of the characteristic conversion circuit 800 is such that the output power of the characteristic conversion circuit 800 becomes maximum when the output voltage of the characteristic conversion circuit 800 has a certain value as shown in FIG. 29A. It is a voltage-output power characteristic. Further, the output voltage-output current characteristic of (i) is characteristic-converted as the output voltage of the characteristic conversion circuit 800 increases in a region where the output voltage of the characteristic conversion circuit 800 crosses a certain value as shown in FIGS. 29A and 30. This is an output voltage-output current characteristic in which the output current of the circuit 800 becomes small.
  • the region where the output voltage of the characteristic conversion circuit 800 crosses the certain value is the region from the first value where the output voltage of the characteristic conversion circuit 800 is smaller than the certain value to the second value which is larger than the certain value. is there.
  • the above-mentioned certain value is specifically a value within a predetermined range, as in the first embodiment.
  • the DC power conversion device 20 is designed to be able to execute MPPT control of the solar power generation system that maximizes output power when the output voltage is within the predetermined range.
  • the characteristic conversion circuit 800 has the output voltage-output power characteristic of (i) above in which the output power becomes maximum when the output voltage has a value within the predetermined range.
  • the characteristic conversion circuit 800 has an output voltage-output current characteristic in which the output current of the characteristic conversion circuit 800 decreases as the output voltage of the characteristic conversion circuit 800 increases in a region where the output voltage crosses a certain value. ..
  • the output voltage-output power characteristic of the fuel cell power generation system is not necessarily suitable for power extraction by MPPT control.
  • the characteristic conversion circuit 800 having the output voltage-output power characteristic of the above (i) outputs power from the fuel cell power generation system 40 to the DC power conversion device 20 by executing MPPT control using the DC power conversion device 20. Allow to take out.
  • the characteristic conversion circuit 800 it is easy to extract a large amount of power from the fuel cell power generation system 40 to the DC power conversion device 20 based on the MPPT control.
  • this point will be described with reference to FIGS. 29A and 29B.
  • the output current-output current characteristic of the characteristic conversion circuit 800 decreases. Due to this output voltage-output current characteristic, as shown in FIG. 29A, in the graph of the output voltage-output power characteristic of the characteristic conversion circuit 800, the output power is convex upward with respect to the output voltage in the region crossing the certain value. Can be curved.
  • the graph of the output voltage-output power characteristic of the characteristic conversion circuit 800 is a single-peak graph in which the output power becomes maximum when the output voltage has the above-mentioned certain value.
  • a graph of the output voltage-output power characteristic of the characteristic conversion circuit 800 is shown. It is assumed that the output power has a linear shape that is convex upward with respect to the output voltage, as shown in FIG. In this case, it is assumed that the MPPT control is executed but the operating point is adjusted to a point deviating from the maximum power point. Specifically, it is assumed that the output voltage of the characteristic conversion circuit 800 is adjusted to the voltage V real deviated from the output voltage V target at the maximum power point. In this case, the output power of the characteristic conversion circuit 800 decreases as compared with the case where the operating point is adjusted to the maximum power point. In FIG. 29B, this decrease width is described as ⁇ P B.
  • the output power of the characteristic conversion circuit 800 becomes Decrease.
  • the amount of decrease is different.
  • the decrease width ⁇ P A in the case of FIG. 29A is smaller than the decrease width ⁇ P B of FIG. 29B.
  • the fact that the graph of the output voltage-output power characteristic has a curved shape that is convex upward suppresses the reduction range of the output power due to the above-described deviation, and allows the fuel cell power generation system 40 to move to the DC power conversion device 20. Therefore, it is advantageous from the viewpoint of suppressing the reduction range of the electric power taken out.
  • the output characteristic of the characteristic conversion circuit 800 of the fourth embodiment has an advantage that it is possible to suppress a decrease in output power due to the MPPT control method and resolution.
  • This output characteristic has a real merit.
  • this output characteristic has an advantage that the compatibility of the characteristic conversion circuit 800 is enhanced and the restrictions of the DC power conversion device 20 that can be adopted are reduced.
  • the output current-output power characteristic of (ii) shows that the output power of the characteristic conversion circuit 800 is the maximum when the output current of the characteristic conversion circuit 800 is the switching current i sw as shown in FIGS. 29A and 30.
  • the output current-output power characteristics are as follows.
  • the switching current isw is the output current of the characteristic conversion circuit 800 when the first feedback control and the second feedback control are switched.
  • the switching current isw depends on the error in detection of the output current of the characteristic conversion circuit 800 by the current sensor 128, and changes when the variable parameter is changed. Since this point is the same as the third embodiment, detailed description will be omitted.
  • the characteristic conversion circuit 800 causes the output voltage of the characteristic conversion circuit 800 to be larger than the certain value and smaller than the open circuit voltage by the first feedback control and the second feedback control.
  • the output voltage-output current characteristic of the characteristic conversion circuit 800 becomes smaller as the output voltage of the characteristic conversion circuit 800 becomes larger.
  • the output voltage-output current characteristic becomes smaller as the output voltage of the characteristic conversion circuit 800 becomes larger.
  • the open circuit voltage is the output voltage of the characteristic conversion circuit 800 when the output current of the characteristic conversion circuit 800 is zero.
  • the output characteristics have both an area in which the output voltage is larger than the first value and smaller than the certain value and an area in which the output voltage is larger than the certain value and smaller than the second value.
  • the output current linearly decreases as the output voltage increases. That is, the output characteristic is a characteristic in which the output current decreases in the form of a linear function with respect to the output voltage in both of the above regions.
  • the output characteristic can be a characteristic in which the output power changes in the form of a quadratic function with respect to the output voltage in both of the above regions.
  • the output characteristics are such that the output voltage is in both the region where the output voltage is larger than 0 and smaller than the certain value and the region where the output voltage is from the certain value to the open circuit voltage value.
  • the characteristic is that the output current becomes linearly smaller as becomes larger. That is, the output characteristic is a characteristic in which the output current decreases in the form of a linear function with respect to the output voltage in both of the above regions.
  • the output characteristic can be a characteristic in which the output power changes in the form of a quadratic function with respect to the output voltage in both of the above regions.
  • the point where the voltage is zero and the power is zero is defined as the origin.
  • the maximum power point can be said to be the point where the voltage has the above-mentioned value and the power is maximum.
  • the point where the voltage is the open circuit voltage and the power is zero is defined as the open circuit voltage point.
  • the straight line connecting the origin and the maximum power point is defined as the first straight line.
  • the straight line connecting the maximum power point and the open circuit voltage point is defined as the second straight line.
  • the region where the output voltage in the graph of the output voltage-output power characteristic is larger than the first value and smaller than the certain value is on the higher power side than the first straight line.
  • a region where the output voltage in the graph of the output voltage-output power characteristic is larger than the certain value and smaller than the second value is on the higher power side than the second straight line.
  • a region where the output voltage in the graph of the output voltage-output power characteristic is larger than 0 and smaller than the above certain value is on the higher power side than the first straight line.
  • the region where the output voltage is from the certain value to the open circuit voltage is on the higher power side than the second straight line.
  • the output voltage-output current characteristic of the characteristic conversion circuit 800 becomes as shown by the broken lines in FIGS. 29A and 30.
  • the output voltage-output power characteristic of the characteristic conversion circuit 800 has a single peak and an upward convex shape as shown by the solid line in FIG. 29A.
  • the output voltage-output power characteristic that is convex above the characteristic conversion circuit 800 enables the MPPT control by the DC power conversion device 20.
  • the MPPT control of the characteristic conversion circuit 800 can be executed by the DC power conversion device 20.
  • the configuration of the characteristic conversion circuit 800 will be further described.
  • the first circuit 810 includes a first resistor 621, a second resistor 622, a sixth resistor 850, a current sensor 128, and a first shunt regulator 625.
  • the second circuit 820 includes a sixth resistor 850, a current sensor 128, a sensor voltage adjustment circuit 820a, and a voltage/current conversion circuit 820b.
  • the current sensor 128 and the sixth resistor 850 are shared by the first circuit 810 and the second circuit 820.
  • the feedback current supply unit 130 has a current supply power supply 131 and a third resistor 132.
  • the current supply power source 131 is a constant voltage source.
  • the voltage/current control circuit 160 increases the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 as the current flowing out from the current supply power source 131 is smaller. As described above, in the characteristic conversion circuit 800, the ratio is adjusted according to the current flowing out from the current supply power source 131.
  • the current sensor 128 has the configuration shown in FIG. 22 as in the third embodiment.
  • the first sensor voltage V1 generated by the current sensor 128 is given by Equation 4 above.
  • another current sensor such as a Hall element type current sensor may be used as the current sensor 128, and the output of the current sensor may be used as the first sensor voltage V1.
  • the first shunt regulator 625 has the configuration shown in FIG. 21 as in the third embodiment.
  • the first shunt regulator 625 causes the first reference voltage V ref1 to follow the constant first reference voltage V s1 .
  • the output voltage V out of the characteristic conversion circuit 800 in the first feedback control is given by the following Expression 9.
  • R621 is the resistance value of the first resistor 621
  • R622 is the resistance value of the second resistor 622
  • R850 is the resistance value of the sixth resistor 850.
  • the first shunt regulator 625 causes the first reference voltage V ref1 to follow the constant first reference voltage V s1 .
  • a constant current flows through the second resistor 622. This means that when the current flowing through the sixth resistor 850 toward the first connection point p1 increases, the current flowing through the first resistor 621 toward the first connection point p1 decreases. The reduction of this current means that the voltage generated in the first resistor 621 is reduced.
  • the operation of the first circuit 810 in the first feedback control can be described as follows.
  • the voltage generated in the first resistor 621 decreases with the voltage at the first connection point p1 following the first reference voltage V ref1 .
  • the output voltage V out of the characteristic conversion circuit 800 decreases.
  • the first feedback control provides output voltage-output current characteristics as shown in FIGS. 29A and 30, in which the output current of the characteristic conversion circuit 800 decreases as the output voltage of the characteristic conversion circuit 800 increases. ..
  • the open circuit voltage of the characteristic conversion circuit 800 is controlled by the first feedback control.
  • the open circuit voltage is the output of the characteristic conversion circuit 800 when the output current of the characteristic conversion circuit 800 is zero. Since the output current of the characteristic conversion circuit 800 is zero, I load becomes zero in Formula 4, and V1 becomes equal to the bias voltage V bias . Therefore, V out defined by Expression 9 has a fixed value. This fixed value corresponds to the open circuit voltage of the characteristic conversion circuit 800.
  • the first shunt regulator 625 and the voltage/current control circuit 160 work to control the first current i1 so that the output voltage V out of the voltage/current control circuit 160 becomes a voltage determined by Expression 9. As a result, the open circuit voltage is set to the specified value.
  • the second sensor voltage V2 is given by Equation 5 above.
  • the adjustment current i3 when V2 ⁇ V3 is given by the above-mentioned formula 6.
  • the adjustment current i3 when V2 ⁇ V3 is given by the above-mentioned formula 7.
  • the output voltage V out is given by a mathematical formula different from the mathematical formula 8 described in the third embodiment.
  • the first shunt regulator 625 causes the first reference voltage V ref1 to follow the constant first reference voltage V s1 .
  • the output voltage V out is given by Equation 10 below.
  • R621 is the resistance value of the first resistor 621.
  • R622 is the resistance value of the second resistor 622, and
  • R850 is the resistance value of the sixth resistor 850.
  • Expression 10 indicates that the output voltage V out of the characteristic conversion circuit 800 decreases as the sensor output from the current sensor 128 (specifically, the first sensor voltage V1) increases and the adjustment current i3 increases. There is.
  • the adjustment current i3 acts to adjust the output voltage V out .
  • the adjustment current i3 can be referred to as the output voltage adjustment current i3.
  • the second circuit 820 can be referred to as an adjustment circuit.
  • FIG. 32 shows the output characteristic of the characteristic conversion circuit 800 before adjustment for suppressing the influence of individual variation.
  • FIG. 33 is a diagram for explaining the adjustment.
  • FIG. 34 shows the output characteristic of the characteristic conversion circuit 800 after adjustment for suppressing the influence of individual variation.
  • the current sensor 128 has the configuration shown in FIG.
  • the resistance value R sense of the shunt resistor 128r, the gain G, and the bias voltage V bias are ideally reference values. However, the resistance value R sense , the gain G, and/or the bias voltage V bias may have an error in the tolerance range.
  • the current sensor 128 outputs a larger first sensor voltage V1 when the resistance value of the shunt resistor 128r is larger than the reference value, compared to when the resistance value of the shunt resistor 128r is the reference value. It is configured.
  • the current sensor 128 is configured to output a larger first sensor voltage V1 when the gain G is larger than the reference value, compared to when the gain G is the reference value.
  • FIG. 32 the horizontal axis represents the output current of the characteristic conversion circuit 800.
  • FIG. 32 shows the output characteristic of the characteristic conversion circuit 800 when the resistance value R sense is changed when the gain G and the bias voltage V bias are at the reference values.
  • output voltage (0) of characteristic conversion circuit indicates the output voltage of the characteristic conversion circuit 800 when the resistance value R sense of the shunt resistor 128r is at the reference value.
  • the “output voltage (+) of the characteristic conversion circuit” indicates the same output voltage when the resistance value R sense is larger than the reference value.
  • Output voltage ( ⁇ ) of characteristic conversion circuit” indicates the same output voltage when the resistance value R sense is smaller than the reference value.
  • Adjustment current i3(0) indicates the adjustment current i3 when the resistance value R sense of the shunt resistor 128r is at the reference value.
  • Adjustment current i3(+) indicates the adjustment current i3 when the resistance value R sense is larger than the reference value.
  • Adjustment current i3( ⁇ ) indicates the adjustment current i3 when the resistance value R sense is smaller than the reference value.
  • Output power of characteristic conversion circuit (0) indicates the output power of the characteristic conversion circuit 800 when the resistance value R sense is at the reference value.
  • the “output power (+) of the characteristic conversion circuit” indicates the same output power when the resistance value R sense is larger than the reference value.
  • Output power ( ⁇ ) of characteristic conversion circuit” indicates the same output power when the resistance value R sense is smaller than the reference value.
  • Switchching current i sw (0) indicates the switching current i sw when the resistance value R sense is at the reference value.
  • switching current i sw (+) indicates the switching current i sw when the resistance value R sense is larger than the reference value.
  • switching current i sw ( ⁇ ) indicates the switching current i sw when the resistance value R sense is smaller than the reference value.
  • the switching current isw is the output current of the characteristic conversion circuit 800 when the first feedback control and the second feedback control are switched.
  • the switching current isw matches the target current.
  • “Switching current isw (0)" corresponds to the target current.
  • the switching current isw is smaller than when the resistance value R sense is at the reference value.
  • the switching current i sw is larger than when the resistance value R sense is at the reference value.
  • the maximum power of the characteristic conversion circuit 800 matches the target power.
  • the “output power (0) of the characteristic conversion circuit” when the output current of the characteristic conversion circuit 800 is the “switching current i sw (0)” corresponds to the target power.
  • the maximum power is smaller than when the resistance value R sense is at the reference value.
  • the resistance value R sense is smaller than the reference value, the maximum power is larger than when the resistance value R sense is at the reference value.
  • variable voltage V4 by adjusting the variable voltage V4, it is possible to adjust the switching current isw of the characteristic conversion circuit 800 and adjust the maximum power.
  • variable voltage V4 is made smaller and the switching current isw is adjusted as compared with the case where the resistance value R sense is at the reference value, so that the maximum power is targeted. It can approach electric power.
  • variable voltage V4 is increased to adjust the switching current i sw to increase the maximum power as compared with the case where the resistance value R sense is at the reference value. It is possible to approach the target power.
  • the adjusted current i3 starts to flow when the output current of the characteristic conversion circuit 800 is larger.
  • the second sensor voltage V2 is reduced, the adjusted current i3 starts to flow when the output current of the characteristic conversion circuit 800 is smaller.
  • the adjustment of the variable voltage V4 can change the adjustment current i3 and the maximum power.
  • a power meter for measuring output power and an electronic load device as a load are connected to the output section of the characteristic conversion circuit 800.
  • the initial value of the variable voltage V4 is set to a sufficiently large voltage. Then, in this adjustment example, the value of the variable voltage V4 after being appropriately adjusted is smaller than the initial value. Strictly speaking, as shown in FIG. 32, the output current-output power characteristic of the characteristic conversion circuit 800 in the first feedback control fluctuates due to the individual variation of the resistance value R sense . In the explanation, it is assumed that this fluctuation is small enough to be ignored.
  • the characteristic conversion circuit 800 is operated.
  • the output current from the characteristic conversion circuit 800 is gradually increased to adjust the output power of the characteristic conversion circuit 800 to a target value.
  • This target value is a value corresponding to the adjusted maximum power point.
  • the variable voltage V4 is gradually reduced.
  • the switching current isw decreases gradually, and when the variable voltage V4 has a certain value, the output power starts to decrease from the target value as the maximum power decreases.
  • the operating point of the characteristic conversion circuit 800 is set to the operating point when this decrease begins. In this way, the output voltage of the characteristic conversion circuit 800 is adjusted to the maximum power point (target value).
  • the electronic load device has a constant current (CC: Constant Current) mode.
  • CC Constant Current
  • the output current from the characteristic conversion circuit 800 can be gradually increased by gradually increasing the set value of the load current, which is the current flowing through the electronic load device.
  • the electronic load device has a constant resistance (CR) mode.
  • CR constant resistance
  • the output current from the characteristic conversion circuit 800 can be gradually increased by gradually decreasing the set value of the load resistance that is the resistance of the electronic load device.
  • the electronic load device may have both the CC mode and the CR mode, or may have one of them.
  • FIG. 33B shows the adjustment current i3a and the switching current i swa .
  • the current i3a is the adjusted current i3 after the adjustment of the variable voltage V4 and the second sensor voltage V2.
  • the current iswa is the switching current isw at this time. Note that the switching current iswa is also shown in FIG. 33A for the purpose of facilitating understanding of the description.
  • the maximum power point can be brought close to the operating point when the resistance value R sense is at the reference value.
  • Equation 11 Equation 11
  • a characteristic conversion circuit 800X which is a specific example of the characteristic conversion circuit 800, is shown in FIG. As can be understood from FIG. 35, the characteristic conversion circuit 800X can be configured following the characteristic conversion circuit 100X of FIG. 8 of the first embodiment. Therefore, detailed description of the characteristic conversion circuit 800X will be omitted.
  • each embodiment can be applied to each other as long as there is no technical contradiction.
  • the respective embodiments may be combined with each other as long as there is no technical conflict.
  • the arrangement of the secondary interconnection breaker 83 shown in FIGS. 27 and 28 is applicable not only to the fourth embodiment but also to the first to third embodiments.
  • the fuel cell system 40 includes a voltage detection circuit 57 and a current detection circuit 58.
  • the voltage detection circuit 57 detects the voltage in the path for guiding the AC power from the fuel cell power generation system 40 to the first branch section 85 via the secondary interconnection breaker 83.
  • the current detection circuit 58 cooperates with a current sensor provided at a position between the third connection point p3 and the main breaker 82 in the upstream electric circuit 88 to detect the current flowing through this position.
  • the detection values obtained by these detection circuits 57 and 58 can be used for controlling the power system 700.
  • the controller 51 switches the protection relay 62 between the open state and the closed state based on the detection values obtained by the detection circuits 57 and 58.
  • the detection circuits 57 and 58 and the control using them are also applicable to the first to third embodiments.
  • the number of solar power generation systems in the power system may be one, or may be three or more.
  • the power system may not have a solar power generation system.
  • the DC power converter does not have to be incorporated in the power station.
  • the power system may not include some of the illustrated elements such as a power storage device and a hot water storage unit.
  • the connection path between the power generation unit and the load is not limited to the illustrated one. For example, it is possible to omit the outlet 260 and supply power to the first load 251.
  • the DC power supply system includes A fuel cell power generation system, A characteristic conversion circuit to which DC power output from the fuel cell power generation system is input, the characteristic conversion circuit performing characteristic conversion control,
  • the characteristic conversion control provides an output voltage-output power characteristic that maximizes the output power of the characteristic conversion circuit when the output voltage of the characteristic conversion circuit has a certain value
  • the characteristic conversion control includes a first feedback control and a second feedback control, The first feedback control is control performed when the output current of the characteristic conversion circuit is relatively small, The second feedback control is control performed when the output current of the characteristic conversion circuit is relatively large, When the first feedback control and the second feedback control are switched, the output voltage of the characteristic conversion circuit becomes the certain value.
  • the DC power supply system according to the first aspect includes a fuel cell power generation system.
  • the MPPT control is executed by the DC power conversion device. By doing so, it is possible to extract electric power from the fuel cell power generation system to the DC power conversion device.
  • the output characteristic of the characteristic conversion circuit may be determined by an analog circuit included in the characteristic conversion circuit.
  • the characteristic conversion control may be executed based on an electric output of the characteristic conversion circuit.
  • the characteristic conversion circuit for example, in the DC power supply system according to the first aspect or the second aspect, The characteristic conversion circuit, A current sensor, at least one voltage dividing resistor, and a voltage/current control circuit that is a DCDC converter may be included, Using the current sensor, the output current of the characteristic conversion circuit may be reflected in the characteristic conversion control, The output voltage of the characteristic conversion circuit may be reflected in the characteristic conversion control using the at least one voltage dividing resistor, The transformation ratio of the voltage/current control circuit may be adjusted by the characteristic conversion control.
  • the output current and output voltage of the characteristic conversion circuit can be reflected in the transformation ratio of the voltage/current control circuit.
  • the ratio of the output current decrease to the increase of the output voltage in the output voltage-output current characteristic is larger, and/or the output in the output voltage-output current characteristic than the second feedback control.
  • the ratio of decrease in output voltage to increase in current may be small.
  • the fourth aspect it is easy to make the output characteristic of the characteristic conversion circuit close to the output characteristic of the solar power generation system.
  • the open circuit voltage may be controlled by the first feedback control.
  • the fifth mode is suitable for preventing the output voltage of the characteristic conversion circuit from becoming excessively large.
  • the fifth aspect is suitable for preventing a voltage exceeding the withstand voltage from being supplied to the DC power converter when the output voltage of the DC power supply system is supplied to the DC power converter.
  • the first feedback control is control performed when the output current of the characteristic conversion circuit is relatively small and the output voltage thereof is relatively large, and the first feedback control of the characteristic conversion circuit increases as the output voltage of the characteristic conversion circuit increases. It may be a control that reduces the output current and the output power,
  • the second feedback control is control performed when the output current of the characteristic conversion circuit is relatively large and the output voltage is relatively small, and the second feedback control of the characteristic conversion circuit increases as the output voltage of the characteristic conversion circuit increases.
  • the characteristic conversion control brings about an output voltage-output current characteristic in which the output current of the characteristic conversion circuit decreases as the output voltage of the characteristic conversion circuit increases in a region where the output voltage of the characteristic conversion circuit crosses the certain value. Good.
  • the sixth aspect by executing the MPPT control using the DC power conversion device designed to execute the MPPT control of the solar power generation system, a large amount of power is supplied from the fuel cell power generation system to the DC power conversion device. Easy to take out.
  • a voltage/current control circuit that is a DCDC converter, a first feedback circuit that performs the first feedback control, and a second feedback circuit that performs the second feedback control may be provided.
  • the first feedback circuit may include a first shunt regulator to which a first reference voltage that changes according to the output current and the output voltage of the characteristic conversion circuit is input.
  • the second feedback circuit may include a second shunt regulator to which a second reference voltage that changes according to the output current and the output voltage of the characteristic conversion circuit is input.
  • the transformation ratio of the voltage/current control circuit may be adjusted using the first shunt regulator so that the first reference voltage is maintained constant.
  • the transformation ratio of the voltage/current control circuit may be adjusted by using the second shunt regulator so that the second reference voltage is maintained constant.
  • the first feedback control and the second feedback control can be realized.
  • the first feedback circuit may include a first voltage dividing resistor
  • the second feedback circuit may include a second voltage dividing resistor
  • the first feedback circuit and the second feedback circuit may share a current sensor
  • the output voltage of the characteristic conversion circuit may be reflected on the first reference voltage by using the first voltage dividing resistor
  • the output current of the characteristic conversion circuit may be reflected on the first reference voltage using the current sensor
  • the output voltage of the characteristic conversion circuit may be reflected on the second reference voltage by using the second voltage dividing resistor
  • the output current of the characteristic conversion circuit may be reflected in the second reference voltage using the current sensor. According to such a circuit configuration, the first reference voltage and the second reference voltage can be obtained.
  • the characteristic conversion circuit A current sensor that detects the output current of the characteristic conversion circuit and outputs a sensor output that represents the result of the detection, and a current sensor that outputs the sensor output as the output current of the characteristic conversion circuit increases.
  • a regulator may be included, In the characteristic conversion circuit, (I) An output voltage-output power characteristic is obtained in which the output power of the characteristic conversion circuit becomes maximum when the output voltage of the characteristic conversion circuit has the certain value, and (Ii) When the output current of the characteristic conversion circuit when the first feedback control and the second feedback control are switched is defined as a switching current, when the output current of the characteristic conversion circuit is the switching current, In order to provide the output current-output power characteristic that maximizes the output power of the characteristic conversion circuit, The first feedback control may be executed when the sensor output is relatively small, and the second feedback control may be executed when the sensor output is relatively large, The switching current depends on the detection error and may change when a variable parameter of the regulator is changed.
  • the DC power supply system according to the eighth aspect is suitable for adjusting the extracted power.
  • the sensor output may be a first sensor voltage
  • the variable output may be a variable voltage
  • the second circuit may include a sensor voltage adjustment circuit that generates a second sensor voltage that changes according to the first sensor voltage and the variable voltage.
  • the variable voltage can be reflected on the second sensor voltage.
  • the current sensor may include a sensor output unit that outputs the first sensor voltage, The sensor voltage adjustment circuit, Input resistance, Feedback resistor, A sensor input terminal connected to the sensor output unit via the input resistor, a variable voltage input terminal to which the variable voltage is input, and a second sensor voltage connected to the sensor input terminal via the feedback resistor.
  • a sensor voltage adjustment operational amplifier including an output terminal, the sensor generating the second sensor voltage based on a voltage difference between the sensor input terminal and the variable voltage input terminal and outputting the second sensor voltage from the second sensor voltage output terminal.
  • a voltage adjustment operational amplifier may be included.
  • the second circuit may include a voltage-current conversion circuit in which an adjustment current starts to flow when the second sensor voltage changes across a threshold voltage due to an increase in the first sensor voltage,
  • the first feedback control may be switched to the second feedback control when the adjustment current starts to flow. In such a mode, the first feedback control is switched to the second feedback control at the timing when the regulated current starts to flow.
  • the characteristic conversion circuit whose control is switched at the timing when the current starts to flow is easy to design.
  • the voltage-current conversion circuit A voltage supply power source for outputting the threshold voltage, Intervening resistance,
  • a transistor drive operational amplifier including a power supply input terminal connected to the voltage supply power supply via the intervening resistor, a second sensor voltage input terminal to which the second sensor voltage is input, and a control voltage output terminal.
  • a transistor drive operational amplifier that generates a control voltage based on a voltage difference between the power supply input terminal and the second sensor voltage input terminal and outputs the control voltage from the control voltage output terminal,
  • An adjustment current output transistor including a control terminal to which the control voltage is input, a first terminal connected to the voltage supply power source via the intervening resistor, and a second terminal for outputting the adjustment current. May be included.
  • the sensor output may be a first sensor voltage
  • the regulator may be a DCDC converter that transforms the first sensor voltage
  • the variable parameter may be a parameter that changes a transformation ratio of the DCDC converter.
  • the sensor output may be a first sensor voltage
  • the regulator may include a voltage divider circuit and an amplifier circuit
  • the variable parameter may be a parameter included in the voltage dividing circuit or the amplifier circuit
  • the sensor output unit, the voltage dividing circuit, and the amplifier circuit may be connected in this order.
  • the voltage dividing circuit may include a variable resistor,
  • the variable parameter may be a resistance value of the variable resistor.
  • the amplifier circuit may include an operational amplifier and a feedback circuit of the operational amplifier,
  • the feedback circuit may include a variable resistor,
  • the variable parameter may be a resistance value of the variable resistor.
  • a first circuit that executes the first feedback control that increases the output power of the characteristic conversion circuit as the sensor output increases; There may be provided a second circuit that cooperates with the first circuit to execute the second feedback control that reduces the output power of the characteristic conversion circuit as the sensor output increases.
  • the variable parameter may be a variable output
  • the regulator may be a variable output power supply that outputs the variable output.
  • the configuration of the ninth aspect is one specific example of the configuration in which the extracted power can be adjusted.
  • a power system according to a tenth aspect of the present disclosure, A DC power supply system according to any one of the first to ninth aspects, A photovoltaic power generation system having a maximum output power when the output voltage is within a predetermined range, and a DC power conversion device designed to perform MPPT control, DC power generated in the fuel cell power generation system is supplied to the DC power converter, The characteristic conversion circuit is provided on a path connecting the fuel cell power generation system and the DC power conversion device, The certain value is a value within the predetermined range.
  • the power system according to the tenth aspect includes a DC power conversion device designed to execute MPPT control of the solar power generation system. According to the power system of the tenth aspect, it is possible to extract power from the fuel cell power generation system to the DC power converter by executing the MPPT control using the DC power converter.
  • An electric power system is A DC power supply system according to an eighth aspect or a ninth aspect;
  • a DC power conversion device designed to perform MPPT control for a photovoltaic power generation system in which output power is maximum when the output voltage is within a predetermined range, At least one solar power generation system that maximizes output power when the output voltage is within the predetermined range;
  • a controller DC power generated in the fuel cell power generation system is supplied to the DC power converter,
  • the characteristic conversion circuit is provided on a path connecting the fuel cell power generation system and the DC power conversion device, The certain value is a value within the predetermined range, DC power generated by the at least one photovoltaic system is supplied to the DC power converter,
  • the controller changes the variable parameter according to a power generation output of the at least one solar power generation system.
  • the output power of the characteristic conversion circuit can be adjusted according to the power generation output of at least one solar power generation system.
  • the power generation output may be a power generation voltage
  • the controller uses a control signal representing the generated voltage, (A) changing the variable parameter so that the switching current becomes small when the generated voltage becomes large across the threshold generated voltage, or (B) The variable parameter may be changed so that the switching current decreases as the generated voltage increases.
  • the twelfth aspect is suitable for supplying a sufficient amount of power to the DC power converter.
  • the power system according to any one of the tenth to twelfth aspects is a first photovoltaic power generation system
  • the DC power generated by the first photovoltaic power generation system is You may include the 1st solar power generation system supplied to the said DC power converter device,
  • the DC power converter may include a first DCDC converter and a second DCDC converter,
  • the first DCDC converter may change the output power of the characteristic conversion circuit by MPPT control
  • the second DCDC converter may change the output power of the first solar power generation system by MPPT control.
  • the thirteenth aspect it is possible to realize a multi-string type DC power conversion device that individually performs MPPT control of the solar power generation system and the characteristic conversion circuit.
  • a fourteenth aspect of the present disclosure for example, a power system according to any one of the tenth to thirteenth aspects, At least one photovoltaic power generation system, wherein the DC power generated by the at least one photovoltaic power generation system is supplied to the DC power conversion device; And a power storage device, The at least one solar power generation system, the DC power conversion device, and the power storage device may be connected in this order, The fuel cell power generation system, the characteristic conversion circuit, the DC power conversion device, and the power storage device may be connected in this order.
  • the power storage device can be charged not only from the solar power generation system but also from the fuel cell power generation system.
  • At least one photovoltaic power generation system wherein the DC power generated by the at least one photovoltaic power generation system is supplied to the DC power conversion device;
  • a power storage device An inverter that converts DC power into AC power, You may have an outlet and The at least one solar power generation system, the DC power conversion device, the inverter, and the outlet may be connected in this order,
  • the fuel cell power generation system, the characteristic conversion circuit, the DC power conversion device, the inverter, and the outlet may be connected in this order,
  • the power storage device, the inverter, and the outlet may be connected in this order.
  • power can be supplied from the fuel cell power generation system to the outlet supplied with power from the solar power generation system and the power storage device.
  • Power may be supplied from the power storage device to the fuel cell power generation system.
  • the sixteenth aspect it is possible to activate the fuel cell power generation system by the power of the power storage device at the time of power failure. According to the sixteenth aspect, it is possible to omit the dedicated power supply for starting the fuel cell power generation system at the time of power failure.
  • the present disclosure can also be considered as disclosing a characteristic conversion circuit.
  • the characteristic conversion circuit according to the present disclosure is A characteristic conversion circuit to which direct-current power is input and which executes characteristic conversion control, wherein the characteristic conversion control is an output that maximizes the output power of the characteristic conversion circuit when the output voltage of the characteristic conversion circuit has a certain value. Results in voltage-output power characteristics,
  • the characteristic conversion control includes a first feedback control and a second feedback control, The first feedback control is control performed when the output current of the characteristic conversion circuit is relatively small, The second feedback control is control performed when the output current of the characteristic conversion circuit is relatively large, When the first feedback control and the second feedback control are switched, the output voltage of the characteristic conversion circuit becomes the certain value.
  • the technology according to the present disclosure can be used for a power system including a DC power conversion device designed for a solar power generation system and a fuel cell power generation system.

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Abstract

According to the present invention, a characteristic conversion control provides an output voltage vs. output power characteristic wherein the output power of a characteristic conversion circuit 100 is maximized when the output voltage of the characteristic conversion circuit 100 is at a certain value. The characteristic conversion control includes a first feedback control and a second feedback control. The first feedback control is performed when the output current of the characteristic conversion circuit 100 is relatively low. The second feedback control is performed when the output current of the characteristic conversion circuit 100 is relatively high. The output voltage of the characteristic conversion circuit 100 is at said certain value when switching between the first feedback control and the second feedback control.

Description

直流電力供給システムおよび電力システムDC power supply system and power system
　本開示は、直流電力供給システムおよび電力システムに関する。 The present disclosure relates to a DC power supply system and a power system.
　種々の発電システムが提案されている。発電システムの例として、太陽光発電パネルを用いて発電する太陽光発電システムが挙げられる。発電システムの別の例として、燃料電池を用いて発電する燃料電池発電システムが挙げられる。 　Various power generation systems have been proposed. An example of the power generation system is a solar power generation system that uses a solar power generation panel to generate power. Another example of the power generation system is a fuel cell power generation system that uses a fuel cell to generate power.
　発電システムでは、電力変換が行われることがある。特許文献１には、電力変換により、太陽光発電システムおよび燃料電池発電システムの出力電圧を所定電圧に変更することが記載されている。 　Power conversion may be performed in the power generation system. Patent Document 1 describes that the output voltage of the photovoltaic power generation system and the fuel cell power generation system is changed to a predetermined voltage by power conversion.
　また、最大電力点追従制御により、太陽光発電システムの電力を取り出すことが知られている。最大電力点追従制御は、ＭＰＰＴ制御とも称される。ＭＰＰＴ制御によれば、太陽光発電システムから取り出される電力が最大化される。具体的には、太陽光発電システムに直流電力変換装置を接続し、直流電力変換装置にＭＰＰＴ制御を実行させることができる。 Also, it is known to extract the power of the solar power generation system by the maximum power point tracking control. The maximum power point tracking control is also called MPPT control. The MPPT control maximizes the electric power extracted from the solar power generation system. Specifically, a direct-current power converter can be connected to the solar power generation system to cause the direct-current power converter to execute MPPT control.
特開２０１７－１１７６７３号公報JP, 2017-117673, A
　太陽光発電システムのＭＰＰＴ制御を実行可能な電力システムを構成する場合、太陽光発電システムのＭＰＰＴ制御を実行できるように直流電力変換装置が設計される。本開示は、燃料電池発電システムを含む直流電力供給システムであって、上記のように設計された直流電力変換装置に接続された状態においてＭＰＰＴ制御が実行されることにより、燃料電池発電システムから直流電力変換装置に電力が取り出され得る直流電力供給システムを提供する。 When configuring a power system that can execute MPPT control of a solar power generation system, a DC power converter is designed so that it can execute MPPT control of the solar power generation system. The present disclosure is a DC power supply system including a fuel cell power generation system, in which MPPT control is executed in a state of being connected to the DC power conversion device designed as described above, so that the DC power is supplied from the fuel cell power generation system. Provided is a DC power supply system from which electric power can be taken out to a power converter.
　本開示は、
　燃料電池発電システムと、
　前記燃料電池発電システムから出力された直流電力が入力される特性変換回路であって、特性変換制御を実行する特性変換回路と、を備え、
　前記特性変換制御は、前記特性変換回路の出力電圧がある値であるときに前記特性変換回路の出力電力が最大となる出力電圧－出力電力特性をもたらし、
　前記特性変換制御は、第１フィードバック制御および第２フィードバック制御を含み、
　前記第１フィードバック制御は、前記特性変換回路の出力電流が相対的に小さいときに行われる制御であり、
　前記第２フィードバック制御は、前記特性変換回路の出力電流が相対的に大きいときに行われる制御であり、
　前記第１フィードバック制御と前記第２フィードバック制御とが切り替わるときに、前記特性変換回路の出力電圧が上記ある値となる、
　直流電力供給システムを提供する。 This disclosure is
A fuel cell power generation system,
A characteristic conversion circuit to which DC power output from the fuel cell power generation system is input, the characteristic conversion circuit performing characteristic conversion control,
The characteristic conversion control provides an output voltage-output power characteristic that maximizes the output power of the characteristic conversion circuit when the output voltage of the characteristic conversion circuit has a certain value,
The characteristic conversion control includes a first feedback control and a second feedback control,
The first feedback control is control performed when the output current of the characteristic conversion circuit is relatively small,
The second feedback control is control performed when the output current of the characteristic conversion circuit is relatively large,
When the first feedback control and the second feedback control are switched, the output voltage of the characteristic conversion circuit becomes the certain value.
Provide a DC power supply system.
　本開示に係る直流電力供給システムは、燃料電池発電システムを含む。本開示に係る直流電力供給システムと、太陽光発電システムのＭＰＰＴ制御を実行できるように設計された直流電力変換装置と、が接続された接続状態において、直流電力変換装置によりＭＰＰＴ制御が実行されることによって、燃料電池発電システムから直流電力変換装置に電力を取り出すことが可能である。 The DC power supply system according to the present disclosure includes a fuel cell power generation system. In the connected state in which the DC power supply system according to the present disclosure and the DC power conversion device designed to execute the MPPT control of the solar power generation system are connected, the MPPT control is executed by the DC power conversion device. As a result, electric power can be taken out from the fuel cell power generation system to the DC power converter.
図１は、系統連系時における電力システムのブロック図である。FIG. 1 is a block diagram of an electric power system during grid interconnection. 図２は、停電時における電力システムのブロック図である。FIG. 2 is a block diagram of the power system during a power failure. 図３Ａは、特性変換回路で得られるＶ－Ｐ特性を説明するための図である。FIG. 3A is a diagram for explaining the VP characteristic obtained by the characteristic conversion circuit. 図３Ｂは、比較形態のＶ－Ｐ特性を説明するための図である。FIG. 3B is a diagram for explaining the VP characteristic of the comparative form. 図４は、特性変換回路の一例を示す図である。FIG. 4 is a diagram illustrating an example of the characteristic conversion circuit. 図５は、電流センサを説明するための図である。FIG. 5 is a diagram for explaining the current sensor. 図６は、第１シャントレギュレータを説明するための図である。FIG. 6 is a diagram for explaining the first shunt regulator. 図７は、第２シャントレギュレータを説明するための図である。FIG. 7 is a diagram for explaining the second shunt regulator. 図８は、特性変換回路の一具体例を示す図である。FIG. 8 is a diagram showing a specific example of the characteristic conversion circuit. 図９は、特性変換回路の別例を示す図である。FIG. 9 is a diagram showing another example of the characteristic conversion circuit. 図１０は、特性変換回路の別の具体例を示す図である。FIG. 10 is a diagram showing another specific example of the characteristic conversion circuit. 図１１は、特性変換回路の一例を示す図である。FIG. 11 is a diagram showing an example of the characteristic conversion circuit. 図１２は、調整器の一例を示す図である。FIG. 12 is a diagram illustrating an example of the adjuster. 図１３は、電流センサの個体ばらつきによる影響を説明するための図である。FIG. 13 is a diagram for explaining an influence due to individual variation of the current sensor. 図１４は、電流センサの個体ばらつきによる影響を説明するための図である。FIG. 14 is a diagram for explaining an influence due to individual variation of the current sensor. 図１５は、電流センサの個体ばらつきによる影響を説明するための図である。FIG. 15 is a diagram for explaining the influence of the individual variation of the current sensor. 図１６は、系統連系時における電力システムのブロック図である。FIG. 16 is a block diagram of the power system at the time of grid interconnection. 図１７は、停電時における電力システムのブロック図である。FIG. 17 is a block diagram of the power system at the time of power failure. 図１８は、特性変換回路の出力特性を説明するための図である。FIG. 18 is a diagram for explaining the output characteristic of the characteristic conversion circuit. 図１９は、特性変換回路の出力特性を説明するための図である。FIG. 19 is a diagram for explaining the output characteristic of the characteristic conversion circuit. 図２０は、特性変換回路の一例を示す図である。FIG. 20 is a diagram illustrating an example of the characteristic conversion circuit. 図２１は、第１シャントレギュレータを説明するための図である。FIG. 21 is a diagram for explaining the first shunt regulator. 図２２は、電流センサを説明するための図である。FIG. 22 is a diagram for explaining the current sensor. 図２３は、電流センサの個体ばらつきによる影響を説明するための図である。FIG. 23 is a diagram for explaining an influence due to individual variation of the current sensor. 図２４は、電流センサの個体ばらつきによる影響を説明するための図である。FIG. 24 is a diagram for explaining an influence due to individual variation of the current sensor. 図２５は、可変電圧による切替電流の調整について説明するための図である。FIG. 25 is a diagram for explaining the adjustment of the switching current by the variable voltage. 図２６は、特性変換回路の具体例を示す図である。FIG. 26 is a diagram showing a specific example of the characteristic conversion circuit. 図２７は、系統連系時における電力システムのブロック図である。FIG. 27 is a block diagram of the power system during grid interconnection. 図２８は、停電時における電力システムのブロック図である。FIG. 28 is a block diagram of the power system at the time of power failure. 図２９Ａは、特性変換回路で得られるＶ－Ｐ特性を説明するための図である。FIG. 29A is a diagram for explaining the VP characteristic obtained by the characteristic conversion circuit. 図２９Ｂは、比較形態のＶ－Ｐ特性を説明するための図である。FIG. 29B is a diagram for explaining the VP characteristic of the comparative form. 図３０は、特性変換回路の出力特性を説明するための図である。FIG. 30 is a diagram for explaining the output characteristic of the characteristic conversion circuit. 図３１は、特性変換回路の一例を示す図である。FIG. 31 is a diagram illustrating an example of the characteristic conversion circuit. 図３２は、電流センサの個体ばらつきによる影響を説明するための図である。FIG. 32 is a diagram for explaining an influence due to individual variation of the current sensor. 図３３は、可変電圧による切替電流の調整について説明するための図である。FIG. 33 is a diagram for explaining the adjustment of the switching current by the variable voltage. 図３４は、調整後の特性変換回路の出力特性を説明するための図である。FIG. 34 is a diagram for explaining the output characteristics of the adjusted characteristic conversion circuit. 図３５は、特性変換回路の具体例を示す図である。FIG. 35 is a diagram showing a specific example of the characteristic conversion circuit.
　本明細書では、第１、第２、第３・・・という序数詞を用いることがある。ある要素に序数詞が付されている場合に、より若番の同種類の要素が存在することは必須ではない。例えば、第３接続点という用語は、第３接続点とともに第１接続点および第２接続点が必ず存在することを意として使用されているわけではない。また、必要に応じて序数詞の番号を変更することができる。 In this specification, the ordinal numbers first, second, third... May be used. When an element has an ordinal number, it is not essential that there be a younger element of the same type. For example, the term third connection point is not used to mean that the first connection point and the second connection point are necessarily present with the third connection point. Also, the ordinal number can be changed if necessary.
　本明細書では、経路という用語を用いることがある。経路は、複数の線路を有し得るものである。接続点等についても同様である。例えば、単相３線式の経路は、２本の非接地線路と１本の接地線路を有する。単相３線式の経路どうしの接続点は、経路における各線路の接続がなされている箇所を含むある範囲の領域を示す意で使用されていると理解するべきである。 In this specification, the term route may be used. The route may have a plurality of lines. The same applies to connection points and the like. For example, the single-phase three-wire type path has two ungrounded lines and one grounded line. It should be understood that the connection point between the single-phase three-wire routes is used to indicate a range of regions including the connection points of the respective lines in the route.
　実施形態では、特性変換回路の出力電流、出力電圧および出力電力の組み合わせを、特性変換回路の動作点と称することがある。特性変換回路の出力電力が最大となるときの動作点を、最大電力点と称することがある。 In the embodiment, the combination of the output current, output voltage, and output power of the characteristic conversion circuit may be referred to as the operating point of the characteristic conversion circuit. The operating point when the output power of the characteristic conversion circuit becomes maximum may be referred to as the maximum power point.
　以下、本開示の実施形態について、図面を参照しながら説明する。本開示は、以下の実施形態に限定されない。 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments.
（第１の実施形態）
　図１および図２は、第１の実施形態に係る電力システム３００のブロック図である。具体的には、図１は、系統連系時の電力の流れの例を示している。図２は、停電時の電力の流れの例を示している。これらの図において、実線は、電力が電路を流れていることを表す。点線は、電力が電路を流れていないことを表す。また、ＶAC1およびＶAC2は、交流電圧を表す。交流電圧ＶAC1の実効値は、交流電圧ＶAC2の実効値よりも小さい。交流電圧ＶAC1の実効値は、例えば１００Ｖである。交流電圧ＶAC2の実効値は、例えば２００Ｖである。この例では、交流電圧ＶAC1の電路または経路は、単相２線式の２本の電線により実現されている。また、交流電圧ＶAC2の電路または経路は、単相３線式の３本の電線のうちの２本の非接地線路により実現されている。 (First embodiment)
1 and 2 are block diagrams of a power system 300 according to the first embodiment. Specifically, FIG. 1 shows an example of the flow of electric power during grid interconnection. FIG. 2 shows an example of the flow of electric power at the time of power failure. In these figures, the solid line represents that electric power is flowing through the electric line. The dotted line represents that no electric power is flowing in the electric line. Further, VAC1 and VAC2 represent alternating voltage. The effective value of the AC voltage V AC1 is smaller than the effective value of the AC voltage V AC2 . The effective value of the AC voltage V AC1 is, for example, 100V. The effective value of the AC voltage V AC2 is, for example, 200V. In this example, the electric path or route of the AC voltage V AC1 is realized by two single-phase two-wire electric wires. Further, the electric line or path of the AC voltage V AC2 is realized by two ungrounded lines of the three single-phase three-wire type electric wires.
　電力システム３００は、系統電源２００と連系する。電力システム３００には、系統電源２００から電力が供給され得る。また、電力システム３００は、系統電源２００に電力を逆潮流させ得る。電力システム３００は、パワーステーション１０と、燃料電池発電システム４０と、基板６０と、太陽光発電システム３１および３２と、蓄電装置２５と、電力切替ユニット２８と、第１分電盤８０と、第２分電盤９０と、負荷２５１，２５２および２５３と、コンセント２６０と、を有する。以下では、第１分電盤８０を主分電盤８０と称することがある。また、第２分電盤９０を自立分電盤９０と称することがある。 The power system 300 is connected to the grid power supply 200. Power can be supplied to the power system 300 from the grid power supply 200. In addition, the power system 300 can cause the system power supply 200 to reversely flow power. The power system 300 includes a power station 10, a fuel cell power generation system 40, a substrate 60, solar power generation systems 31 and 32, a power storage device 25, a power switching unit 28, a first distribution board 80, and a first power distribution panel 80. It has a distribution board 90, loads 251, 252 and 253, and an outlet 260. Hereinafter, the first distribution board 80 may be referred to as a main distribution board 80. Further, the second distribution board 90 may be referred to as an independent distribution board 90.
［パワーステーション１０］
　パワーステーション１０は、直流電力変換装置２０と、第１ＤＣバス１１と、第４ＤＣＤＣコンバータ１２と、第１インバータ１３と、を有する。 [Power Station 10]
The power station 10 includes a DC power converter 20, a first DC bus 11, a fourth DCDC converter 12, and a first inverter 13.
　直流電力変換装置２０は、出力電圧が所定範囲内にあるときに出力電力が最大になる太陽光発電システム対して最大電力点追従制御を実行できるように設計されている。太陽光発電システムは、太陽光発電パネルを用いて発電するシステムである。以下では、最大電力点追従制御を、ＭＰＰＴ制御と称することがある。 The DC power conversion device 20 is designed to be able to perform maximum power point tracking control for a photovoltaic power generation system that maximizes output power when the output voltage is within a predetermined range. The solar power generation system is a system that uses a solar power generation panel to generate power. Hereinafter, the maximum power point tracking control may be referred to as MPPT control.
　直流電力変換装置２０には、太陽光発電システム３１および３２ならびに燃料電池発電システム４０から直流電力が入力される。直流電力変換装置２０から出力された直流電力は、第１ＤＣバス１１に供給される。 DC power is input to the DC power converter 20 from the solar power generation systems 31 and 32 and the fuel cell power generation system 40. The DC power output from the DC power converter 20 is supplied to the first DC bus 11.
　具体的には、直流電力変換装置２０は、第１ＤＣＤＣコンバータ２１と、第２ＤＣＤＣコンバータ２２と、第３ＤＣＤＣコンバータ２３と、を有する。第１ＤＣＤＣコンバータ２１には、燃料電池発電システム４０から直流電力が入力される。第２ＤＣＤＣコンバータ２２には、第１太陽光発電システム３１から直流電力が入力される。第３ＤＣＤＣコンバータ２３には、第２太陽光発電システム３２から直流電力が入力される。これらのＤＣＤＣコンバータ２１，２２および２３から出力された直流電力は、第１ＤＣバス１１に供給される。 Specifically, the DC power conversion device 20 includes a first DCDC converter 21, a second DCDC converter 22, and a third DCDC converter 23. DC power is input to the first DCDC converter 21 from the fuel cell power generation system 40. DC power is input to the second DCDC converter 22 from the first solar power generation system 31. DC power is input to the third DCDC converter 23 from the second solar power generation system 32. The DC power output from these DCDC converters 21, 22, and 23 is supplied to the first DC bus 11.
　第４ＤＣＤＣコンバータ１２は、第１ＤＣバス１１から入力された直流電力を、電圧の異なる直流電力に変換する。第４ＤＣＤＣコンバータ１２で変換された直流電力は、蓄電装置２５に供給される。また、第４ＤＣＤＣコンバータ１２は、蓄電装置２５から入力された電力を、電圧の異なる直流電力に変換し、第１ＤＣバス１１に供給する。つまり、第４ＤＣＤＣコンバータ１２は、双方向ＤＣＤＣコンバータである。第４ＤＣＤＣコンバータ１２は、蓄電装置２５の端子電圧が定格範囲となるように動作する。 The fourth DCDC converter 12 converts the DC power input from the first DC bus 11 into DC power having a different voltage. The DC power converted by the fourth DCDC converter 12 is supplied to the power storage device 25. Further, the fourth DCDC converter 12 converts the electric power input from the power storage device 25 into DC electric power having a different voltage, and supplies the DC electric power to the first DC bus 11. That is, the fourth DCDC converter 12 is a bidirectional DCDC converter. The fourth DCDC converter 12 operates so that the terminal voltage of the power storage device 25 falls within the rated range.
　第１インバータ１３は、直流電力を交流電力に変換する。具体的には、第１インバータ１３は、第１ＤＣバス１１から入力された直流電力を、電圧ＶAC1または電圧ＶAC2の交流電力に変換する。第１インバータ１３で電圧ＶAC1の交流電力が得られる場合、その電力は電力切替ユニット２８に供給される。第１インバータ１３で電圧ＶAC2の交流電力が得られる場合、その電力は主分電盤８０に供給される。 The first inverter 13 converts DC power into AC power. Specifically, the first inverter 13 converts the DC power input from the first DC bus 11 into AC power of the voltage V AC1 or the voltage V AC2 . When the first inverter 13 can obtain the AC power having the voltage V AC1 , the power is supplied to the power switching unit 28. When AC power of voltage V AC2 is obtained by the first inverter 13, the power is supplied to the main distribution board 80.
　第１インバータ１３は、系統電源２００から主分電盤８０を介して入力された電圧ＶAC2の交流電力を、直流電力に変換することもできる。こうして得られた直流電力は、第１ＤＣバス１１および第４ＤＣＤＣコンバータ１２を介して蓄電装置２５に供給される。 The first inverter 13 can also convert the AC power of the voltage V AC2 input from the system power supply 200 via the main distribution board 80 into DC power. The DC power thus obtained is supplied to the power storage device 25 via the first DC bus 11 and the fourth DCDC converter 12.
［太陽光発電システム３１および３２］
　本実施形態では、電力システム３００は、出力電圧が所定範囲内にあるときに出力電力が最大になる太陽光発電システムを少なくとも１つ備える。当該少なくとも１つの太陽光発電システムで生成された直流電力は、直流電力変換装置２０に供給される。 [Solar power generation systems 31 and 32]
In the present embodiment, the power system 300 includes at least one solar power generation system that maximizes output power when the output voltage is within a predetermined range. The DC power generated by the at least one solar power generation system is supplied to the DC power converter 20.
　具体的に、太陽光発電システム３１および３２は、出力電圧が所定範囲内にあるときに出力電力が最大になる太陽光発電システムに該当する。第１太陽光発電システム３１は、少なくとも１つの太陽光発電パネル３６を有する。第１太陽光発電システム３１は、該少なくとも１つの太陽光発電パネル３６を用いて発電する。第２太陽光発電システム３２は、少なくとも１つの太陽光発電パネル３７を有する。第２太陽光発電システム３２は、該少なくとも１つの太陽光発電パネル３７を用いて発電する。太陽光発電システム３１および３２で生成された直流電力は、直流電力変換装置２０に供給される。 Specifically, the solar power generation systems 31 and 32 correspond to the solar power generation systems in which the output power is maximum when the output voltage is within the predetermined range. The first solar power generation system 31 has at least one solar power generation panel 36. The first solar power generation system 31 uses the at least one solar power generation panel 36 to generate power. The second solar power generation system 32 includes at least one solar power generation panel 37. The second solar power generation system 32 uses the at least one solar power generation panel 37 to generate power. The DC power generated by the solar power generation systems 31 and 32 is supplied to the DC power converter 20.
［燃料電池発電システム４０］
　燃料電池発電システム４０は、燃料電池４１を用いて発電するシステムである。燃料電池発電システム４０で生成された直流電力は、直流電力変換装置２０に供給され得る。燃料電池発電システム４０で生成された交流電力は、主分電盤８０に供給され得る。 [Fuel cell power generation system 40]
The fuel cell power generation system 40 is a system that uses a fuel cell 41 to generate power. The DC power generated by the fuel cell power generation system 40 can be supplied to the DC power converter 20. The AC power generated by the fuel cell power generation system 40 may be supplied to the main distribution board 80.
　燃料電池発電システム４０は、燃料電池４１と、第５ＤＣＤＣコンバータ４２と、第２ＤＣバス４３と、第２インバータ４４と、第６ＤＣＤＣコンバータ４５と、ヒーター４６と、貯湯ユニット４７と、制御器５１と、低圧電源５２と、補機用電源５５と、を有する。以下では、補機用電源５５を、Ｄ１電源５５と称することがある。 The fuel cell power generation system 40 includes a fuel cell 41, a fifth DCDC converter 42, a second DC bus 43, a second inverter 44, a sixth DCDC converter 45, a heater 46, a hot water storage unit 47, and a controller 51. It has a low-voltage power supply 52 and an auxiliary power supply 55. Hereinafter, the auxiliary power supply 55 may be referred to as a D1 power supply 55.
　燃料電池４１は、直流電力を発電する。具体的には、燃料電池４１はスタックを含む。そして、スタックが、酸素および水素から直流電力を生成する。 The fuel cell 41 generates DC power. Specifically, the fuel cell 41 includes a stack. The stack then produces DC power from oxygen and hydrogen.
　第５ＤＣＤＣコンバータ４２は、燃料電池４１で生成された直流電力を、電圧の異なる直流電力に変換する。この例では、第５ＤＣＤＣコンバータ４２は、燃料電池４１で生成された直流電力を昇圧する。昇圧された直流電力は、第２ＤＣバス４３に供給される。 The fifth DCDC converter 42 converts the DC power generated by the fuel cell 41 into DC power having a different voltage. In this example, the fifth DCDC converter 42 boosts the DC power generated by the fuel cell 41. The boosted DC power is supplied to the second DC bus 43.
　第２インバータ４４は、第２ＤＣバス４３から入力された直流電力を、電圧ＶAC2の交流電力に変換する。第２インバータ４４で得られた交流電力は、主分電盤８０に供給される。 The second inverter 44 converts the DC power input from the second DC bus 43 into AC power having a voltage V AC2 . The AC power obtained by the second inverter 44 is supplied to the main distribution board 80.
　第６ＤＣＤＣコンバータ４５は、第２ＤＣバス４３から入力された直流電力を、電圧の異なる直流電力に変換する。この例では、第６ＤＣＤＣコンバータ４５は、第２ＤＣバス４３から入力された直流電力を降圧する。 The sixth DCDC converter 45 converts the DC power input from the second DC bus 43 into DC power having a different voltage. In this example, the sixth DCDC converter 45 steps down the DC power input from the second DC bus 43.
　ヒーター４６は、第６ＤＣＤＣコンバータ４５で変換された直流電力を用いて、水を温める。温められた水（以下、湯と称することがある）は、貯湯ユニット４７に貯められる。 The heater 46 uses direct current power converted by the sixth DC/DC converter 45 to warm water. The warmed water (hereinafter sometimes referred to as hot water) is stored in the hot water storage unit 47.
　仮に、燃料電池４１の発電電力が第２インバータ４４の出力先の要求負荷よりも大きいときに、燃料電池発電システム４０が燃料電池４１の発電電力の全てを第２インバータ４４から出力したとする。その場合、第２インバータ４４から出力された電力のうち要求負荷を超える分（以下、余剰電力と称することがある）が系統電源２００に逆潮流されてしまう。逆潮流を避けるために、この例では、余剰電力に所定マージンを加えた電力がゼロよりも大きい場合、その電力を、第２ＤＣバス４３から第６ＤＣＤＣコンバータ４５を介してヒーター４６に供給する。つまり、第６ＤＣＤＣコンバータ４５は、余剰電力用である。また、ヒーター４６は、水を温めつつ、逆潮流を防止する。 It is assumed that the fuel cell power generation system 40 outputs all the power generated by the fuel cell 41 from the second inverter 44 when the power generated by the fuel cell 41 is larger than the required load at the output destination of the second inverter 44. In that case, a part of the power output from the second inverter 44 that exceeds the required load (hereinafter, may be referred to as surplus power) is reversely flown to the system power supply 200. In order to avoid reverse power flow, in this example, when the power obtained by adding a predetermined margin to the surplus power is larger than zero, the power is supplied from the second DC bus 43 to the heater 46 via the sixth DCDC converter 45. That is, the sixth DCDC converter 45 is for surplus power. Further, the heater 46 warms the water and prevents reverse power flow.
　制御器５１は、ＤＣＤＣコンバータ４２および４５と、第２インバータ４４と、後述の保護リレー６２とを制御する。本実施形態では、制御器５１は、マイクロコントロールユニット（ＭＣＵ）である。低圧電源５２は、制御器５１と、保護リレー６２と、後述の特性変換回路１００とに、制御用の電力を供給する。Ｄ１電源５５は、ポンプ、ブロワ、弁などの、燃料電池発電システム４０の補機を動かすのに用いられる。 The controller 51 controls the DCDC converters 42 and 45, the second inverter 44, and a protection relay 62 described later. In this embodiment, the controller 51 is a micro control unit (MCU). The low-voltage power supply 52 supplies control power to the controller 51, the protection relay 62, and the characteristic conversion circuit 100 described later. The D1 power supply 55 is used to operate auxiliary equipment of the fuel cell power generation system 40, such as a pump, a blower, and a valve.
［基板６０］
　基板６０は、燃料電池発電システム４０とパワーステーション１０とを接続する経路上に設けられている。基板６０には、燃料電池発電システム４０から、具体的には第２ＤＣバス４３から、直流電力が供給される。基板６０は、特性変換回路１００と、ＬＣフィルタ６１と、保護リレー６２と、を有する。 [Substrate 60]
The substrate 60 is provided on the path connecting the fuel cell power generation system 40 and the power station 10. Direct current power is supplied to the substrate 60 from the fuel cell power generation system 40, specifically from the second DC bus 43. The substrate 60 has a characteristic conversion circuit 100, an LC filter 61, and a protection relay 62.
　上述の説明から明らかであるように、特性変換回路１００は、燃料電池発電システム４０と直流電力変換装置２０とを接続する経路上、詳細には直流電力の経路上、に設けられている。特性変換回路１００は、特性変換制御を実行する。この例では、燃料電池発電システム４０および特性変換回路１００を含む直流電力供給システムが構成されており、直流電力供給システムから直流電力変換装置２０に直流電力が供給され得る。この点は、後述の実施形態においても同様である。 As is apparent from the above description, the characteristic conversion circuit 100 is provided on the path connecting the fuel cell power generation system 40 and the DC power conversion device 20, more specifically, on the DC power path. The characteristic conversion circuit 100 executes characteristic conversion control. In this example, a DC power supply system including the fuel cell power generation system 40 and the characteristic conversion circuit 100 is configured, and DC power can be supplied from the DC power supply system to the DC power converter 20. This point is the same in the embodiments described later.
　特性変換制御は、特性変換回路１００の出力電圧がある値であるときに特性変換回路１００の出力電力が最大となる出力電圧－出力電力特性をもたらす。 The characteristic conversion control brings about an output voltage-output power characteristic in which the output power of the characteristic conversion circuit 100 becomes maximum when the output voltage of the characteristic conversion circuit 100 has a certain value.
　本実施形態では、直流電力変換装置２０は、出力電圧が所定範囲内にあるときに出力電力が最大になる太陽光発電システムに対して、ＭＰＰＴ制御を実行できるように設計されている。特性変換制御は、特性変換回路１００の出力電圧が上記所定範囲内のある値であるときに特性変換回路１００の出力電力が最大となる出力電圧－出力電力特性をもたらす。 In the present embodiment, the DC power conversion device 20 is designed to be able to perform MPPT control on the solar power generation system that maximizes the output power when the output voltage is within the predetermined range. The characteristic conversion control brings about an output voltage-output power characteristic in which the output power of the characteristic conversion circuit 100 becomes maximum when the output voltage of the characteristic conversion circuit 100 has a value within the predetermined range.
　また、特性変換制御は、特性変換回路１００の出力電圧が上記ある値を跨ぐ領域において、特性変換回路１００の出力電圧が大きくなるほど特性変換回路１００の出力電流が小さくなる出力電圧－出力電流特性をもたらす。ここで、特性変換回路１００の出力電圧が上記ある値を跨ぐ領域は、特性変換回路１００の出力電圧が上記ある値よりも小さい第１の値から上記ある値よりも大きい第２の値までの領域である。 In the characteristic conversion control, in the region where the output voltage of the characteristic conversion circuit 100 crosses a certain value, the output voltage-output current characteristic becomes smaller as the output voltage of the characteristic conversion circuit 100 increases. Bring Here, in the region where the output voltage of the characteristic conversion circuit 100 crosses the certain value, from the first value where the output voltage of the characteristic conversion circuit 100 is smaller than the certain value to the second value which is larger than the certain value. Area.
　上記の出力電圧－出力電力特性および出力電圧－出力電流特性の一例を、図３Ａに示す。図３Ａでは、特性変換回路１００の出力電圧－出力電力特性を、Ｖ－Ｐ特性と記載している。特性変換回路１００の出力電圧－出力電流特性を、Ｖ－Ｉ特性と記載している。実線は、Ｖ－Ｐ特性を表す。点線は、Ｖ－Ｉ特性を表す。 An example of the above output voltage-output power characteristic and output voltage-output current characteristic is shown in FIG. 3A. In FIG. 3A, the output voltage-output power characteristic of the characteristic conversion circuit 100 is described as a VP characteristic. The output voltage-output current characteristic of the characteristic conversion circuit 100 is described as VI characteristic. The solid line represents the VP characteristic. The dotted line represents the VI characteristic.
　上述のように、直流電力変換装置２０は、太陽光発電システムのＭＰＰＴ制御を実行できるように設計されている。特性変換回路１００の特性変換制御は、その直流電力変換装置２０を用いてＭＰＰＴ制御を実行することにより燃料電池発電システム４０から直流電力変換装置２０に電力を取り出すことを可能にする。 As described above, the DC power converter 20 is designed to be able to execute MPPT control of the solar power generation system. The characteristic conversion control of the characteristic conversion circuit 100 makes it possible to extract electric power from the fuel cell power generation system 40 to the DC power converter 20 by executing MPPT control using the DC power converter 20.
　特性変換回路１００により出力電圧－出力電力特性を適切に調整することにより、特性変換回路１００の出力電圧が過度に大きくなることを防止できる。このため、燃料電池発電システム４０から直流電力変換装置２０に過電圧が入力され直流電力変換装置２０が壊れるのを防止できる。 By appropriately adjusting the output voltage-output power characteristic by the characteristic conversion circuit 100, it is possible to prevent the output voltage of the characteristic conversion circuit 100 from becoming excessively large. Therefore, it is possible to prevent the DC power conversion device 20 from being damaged by the overvoltage input from the fuel cell power generation system 40 to the DC power conversion device 20.
　また、特性変換回路１００の出力電圧－出力電力特性によれば、特性変換回路１００の出力電圧が上記のある値となった時点で、特性変換回路１００から直流電力変換装置２０に送られる電力の増加が停止される。このため、特性変換回路１００から直流電力変換装置２０に送られる電力が過度に増加することを防止できる。燃料電池発電システム４０から特性変換回路１００に送られる電力が過度に増加することも防止できる。このため、燃料電池発電システム４０の出力電力の増加に伴って燃料電池発電システム４０の出力電流が過度に増加することを防止できる。このため、保護機能が働いて燃料電池４１の発電が停止され燃料電池発電システム４０から直流電力変換装置２０への電力供給が停止されることを防止できる。 Further, according to the output voltage-output power characteristic of the characteristic conversion circuit 100, when the output voltage of the characteristic conversion circuit 100 reaches the above-mentioned value, the power transmitted from the characteristic conversion circuit 100 to the DC power conversion device 20 is The increase is stopped. Therefore, it is possible to prevent the electric power sent from the characteristic conversion circuit 100 to the DC power conversion device 20 from excessively increasing. It is possible to prevent the electric power sent from the fuel cell power generation system 40 to the characteristic conversion circuit 100 from excessively increasing. Therefore, it is possible to prevent the output current of the fuel cell power generation system 40 from excessively increasing as the output power of the fuel cell power generation system 40 increases. For this reason, it is possible to prevent the protection function from working and the power generation of the fuel cell 41 to be stopped, and the power supply from the fuel cell power generation system 40 to the DC power converter 20 to be stopped.
　また、特性変換回路１００によれば、ＭＰＰＴ制御に基づいて燃料電池発電システム４０から直流電力変換装置２０に大きな電力を取り出し易い。以下、この点について、図３Ａとともに図３Ｂを参照しながら説明する。 Further, according to the characteristic conversion circuit 100, it is easy to extract a large amount of power from the fuel cell power generation system 40 to the DC power conversion device 20 based on the MPPT control. Hereinafter, this point will be described with reference to FIG. 3A as well as FIG. 3A.
　上述のように、特性変換制御は、特性変換回路１００の出力電圧が上記ある値を跨ぐ領域において特性変換回路１００の出力電圧が大きくなるほど特性変換回路１００の出力電流が小さくなる出力電圧－出力電流特性をもたらす。この出力電圧－出力電流特性により、特性変換回路１００の出力電圧－出力電力特性のグラフは、出力電圧が上記ある値を跨ぐ領域において、出力電圧に対して出力電力が上に凸の曲線状となり得る。典型例では、特性変換回路１００の出力電圧－出力電力特性のグラフは、出力電圧が上記ある値のときに出力電力が最大となる単一ピークのグラフである。 As described above, in the characteristic conversion control, the output voltage-output current becomes smaller as the output voltage of the characteristic conversion circuit 100 increases as the output voltage of the characteristic conversion circuit 100 increases in a region where the output voltage of the characteristic conversion circuit 100 exceeds the certain value. Bring characteristics. Due to this output voltage-output current characteristic, the graph of the output voltage-output power characteristic of the characteristic conversion circuit 100 has a curved shape in which the output power is convex upward with respect to the output voltage in the region where the output voltage crosses the certain value. obtain. In a typical example, the graph of the output voltage-output power characteristic of the characteristic conversion circuit 100 is a single peak graph in which the output power becomes maximum when the output voltage has the above-mentioned certain value.
　仮に、特性変換回路１００の出力電圧－出力電力特性のグラフが、図３Ｂに示すような、出力電圧に対して出力電力が上に凸の直線状であったとする。この場合において、ＭＰＰＴ制御を実行したものの、動作点が最大電力点からずれた点に調整されたとする。具体的には、特性変換回路１００の出力電圧が、最大電力点の出力電圧Ｖtargetからずれた電圧Ｖrealに調整されたとする。この場合、特性変換回路１００の出力電力は、動作点が最大電力点に調整された場合に比べ、減少する。図３Ｂでは、この減少幅を、ΔＰBと記載する。 It is assumed that the graph of the output voltage-output power characteristic of the characteristic conversion circuit 100 has a linear shape in which the output power is upward with respect to the output voltage, as shown in FIG. 3B. In this case, it is assumed that the MPPT control is executed but the operating point is adjusted to a point deviating from the maximum power point. Specifically, it is assumed that the output voltage of the characteristic conversion circuit 100 is adjusted to the voltage V real deviated from the output voltage V target at the maximum power point. In this case, the output power of the characteristic conversion circuit 100 decreases as compared with the case where the operating point is adjusted to the maximum power point. In FIG. 3B, this reduction width is described as ΔP B.
　図３Ａの例においても、特性変換回路１００の出力電圧が最大電力点の出力電圧Ｖtargetからずれた電圧Ｖrealに調整されると、特性変換回路１００の出力電力は、動作点が最大電力点に調整された場合に比べ、減少する。図３Ａでは、この減少幅を、ΔＰAと記載する。 Also in the example of FIG. 3A, when the output voltage of the characteristic conversion circuit 100 is adjusted to a voltage V real that is deviated from the output voltage V target of the maximum power point, the output power of the characteristic conversion circuit 100 has an operating point of the maximum power point It is reduced compared to when adjusted to. In FIG. 3A, this reduction width is described as ΔP A.
　上述のように、特性変換回路１００の出力電圧－出力電力特性のグラフが直線状である場合も曲線状である場合も、動作点が最大電力点からずれると、特性変換回路１００の出力電力は減少する。しかし、その減少幅は異なる。具体的には、図３Ａの場合の減少幅ΔＰAは、図３Ｂの減少幅ΔＰBよりも小さい。このように、出力電圧－出力電力特性のグラフが上に凸の曲線状であることは、上記のずれに起因する出力電力の減少幅を抑え、燃料電池発電システム４０から直流電力変換装置２０へと取り出される電力の減少幅を抑える観点から有利である。 As described above, whether the output voltage-output power characteristic graph of the characteristic conversion circuit 100 is linear or curved, if the operating point deviates from the maximum power point, the output power of the characteristic conversion circuit 100 becomes Decrease. However, the amount of decrease is different. Specifically, the decrease width ΔP A in the case of FIG. 3A is smaller than the decrease width ΔP B of FIG. 3B. As described above, the fact that the graph of the output voltage-output power characteristic has a curved shape that is convex upward suppresses the reduction range of the output power due to the above-mentioned deviation, and allows the fuel cell power generation system 40 to transfer to the DC power converter 20. Therefore, it is advantageous from the viewpoint of suppressing the reduction range of the electric power taken out.
　現実のＭＰＰＴ制御には、山登り法の他、取り出し電圧を予め定められた電圧に制御するものもあり、そのような制御では動作点を最大電力点に高い精度で一致させることは必ずしも容易ではない。山登り法でも、制御の分解能によっては安定的に最大電力を取り出せない場合もあり得る。このため、出力電圧－出力電力特性のグラフが上に凸の曲線状であることは、ＭＰＰＴ制御の方式および分解能に起因する出力電力の減少幅を抑えることができる点で、現実にメリットがある。 In the actual MPPT control, there is a method of controlling the extraction voltage to a predetermined voltage in addition to the hill climbing method. In such control, it is not always easy to match the operating point with the maximum power point with high accuracy. .. Even in the hill climbing method, the maximum power may not be stably extracted depending on the control resolution. For this reason, the fact that the graph of the output voltage-output power characteristic has an upwardly convex curve shape has an actual merit in that the reduction range of the output power due to the MPPT control method and the resolution can be suppressed. ..
　また、ユーザーが、ある業者から特性変換回路１００を購入し、別の業者からＭＰＰＴ制御を行う直流電力変換装置２０を購入することもあり得る。その場合、特性変換回路１００は、特性変換回路１００の設計者からみて不明な性能を有する直流電力変換装置２０に接続されることになる。この場合は、特性変換制御とＭＰＰＴ制御とが完全には適合していないことが原因で、動作点が最大電力点からずれた点に調整されることがあり得る。このことからも、出力電圧－出力電力特性のグラフが上に凸の曲線状であることは、現実にメリットがあると言える。また、出力電圧－出力電力特性のグラフが凸の曲線状であることは、特性変換回路１００のコンパティビリティを高め、採用可能な直流電力変換装置２０の制約を小さくするとも言える。 Also, the user may purchase the characteristic conversion circuit 100 from one vendor and the DC power conversion device 20 that performs MPPT control from another vendor. In that case, the characteristic conversion circuit 100 is connected to the DC power conversion device 20 having a performance unknown to the designer of the characteristic conversion circuit 100. In this case, the operating point may be adjusted to a point deviating from the maximum power point because the characteristic conversion control and the MPPT control are not completely compatible. From this, it can be said that the fact that the graph of the output voltage-output power characteristic has a curved shape that is convex upward has an actual merit. It can also be said that the convex curve shape of the output voltage-output power characteristic graph improves the compatibility of the characteristic conversion circuit 100 and reduces the restrictions of the DC power conversion device 20 that can be adopted.
　図３Ａに示すように、特性変換制御は、特性変換回路１００の出力電圧が０よりも大きく上記ある値よりも小さい領域において、特性変換回路１００の出力電圧が大きくなるほど特性変換回路１００の出力電流が小さくなる出力電圧－出力電流特性をもたらすものであってもよい。また、特性変換制御は、特性変換回路１００の出力電圧が上記ある値よりも大きく開放電圧よりも小さい領域において、特性変換回路１００の出力電圧が大きくなるほど特性変換回路１００の出力電流が小さくなる出力電圧－出力電流特性をもたらすものであってもよい。ここで、開放電圧は、特性変換回路１００の出力電流がゼロであるときの特性変換回路１００の出力電圧である。 As shown in FIG. 3A, in the characteristic conversion control, the output current of the characteristic conversion circuit 100 increases as the output voltage of the characteristic conversion circuit 100 increases in a region where the output voltage of the characteristic conversion circuit 100 is larger than 0 and smaller than the certain value. The output voltage-output current characteristic may be reduced. In the characteristic conversion control, the output current of the characteristic conversion circuit 100 becomes smaller as the output voltage of the characteristic conversion circuit 100 becomes larger in the region where the output voltage of the characteristic conversion circuit 100 is larger than the certain value and smaller than the open circuit voltage. It may provide a voltage-output current characteristic. Here, the open circuit voltage is the output voltage of the characteristic conversion circuit 100 when the output current of the characteristic conversion circuit 100 is zero.
　上記ある値よりも小さい値を第１の値と定義する。上記ある値よりも大きい値を第２の値と定義する。このとき、図３Ａの例では、出力特性は、出力電圧が第１の値よりも大きく上記ある値よりも小さい領域と出力電圧が上記ある値よりも大きく第２の値よりも小さい領域の両方において、出力電圧が大きくなるほど出力電流が線形的に小さくなる特性である。つまり、出力特性は、上記の両方の領域において、出力電圧に対して出力電流が一次関数の形態で小さくなる特性である。これにより、出力特性は、上記の両方の領域において、出力電力が出力電圧に対して二次関数の形態で変化する特性となり得る。 Define a value smaller than the above value as the first value. A value larger than the above certain value is defined as a second value. At this time, in the example of FIG. 3A, the output characteristics have both an area where the output voltage is larger than the first value and smaller than the certain value and an area where the output voltage is larger than the certain value and smaller than the second value. In the above, the output current linearly decreases as the output voltage increases. That is, the output characteristic is a characteristic in which the output current decreases in the form of a linear function with respect to the output voltage in both of the above regions. As a result, the output characteristic can be a characteristic in which the output power changes in the form of a quadratic function with respect to the output voltage in both of the above regions.
　具体的には、図３Ａの例では、出力特性は、出力電圧が０よりも大きく上記ある値よりも小さい領域と出力電圧が上記ある値から開放電圧の値までの領域の両方において、出力電圧が大きくなるほど出力電流が線形的に小さくなる特性である。つまり、出力特性は、上記の両方の領域において、出力電圧に対して出力電流が一次関数の形態で小さくなる特性である。これにより、出力特性は、上記の両方の領域において、出力電力が出力電圧に対して二次関数の形態で変化する特性となり得る。 Specifically, in the example of FIG. 3A, the output characteristics are such that the output voltage is in both the region where the output voltage is larger than 0 and smaller than the certain value and the region where the output voltage is from the certain value to the open circuit voltage value. The characteristic is that the output current becomes linearly smaller as becomes larger. That is, the output characteristic is a characteristic in which the output current decreases in the form of a linear function with respect to the output voltage in both of the above regions. As a result, the output characteristic can be a characteristic in which the output power changes in the form of a quadratic function with respect to the output voltage in both of the above regions.
　出力電圧－出力電力特性のグラフにおいて、電圧がゼロかつ電力がゼロである点を原点と定義する。出力電圧－出力電力特性のグラフにおいて、最大電力点は、電圧が上記ある値であり電力が最大である点と言える。出力電圧－出力電力特性のグラフにおいて、電圧が開放電圧であり電力がゼロである点を、開放電圧点と定義する。出力電圧－出力電力特性のグラフにおいて、原点と最大電力点とを結ぶ直線を第１直線と定義する。出力電圧－出力電力特性のグラフにおいて、最大電力点と開放電圧点とを結ぶ直線を第２直線と定義する。このとき、図３Ａの例では、出力電圧－出力電力特性のグラフにおける出力電圧が第１の値よりも大きく上記ある値よりも小さい領域が、第１直線よりも高電力側にある。出力電圧－出力電力特性のグラフにおける出力電圧が上記ある値よりも大きく第２の値よりも小さい領域が、第２直線よりも高電力側にある。 In the graph of output voltage-output power characteristics, the point where the voltage is zero and the power is zero is defined as the origin. In the graph of the output voltage-output power characteristic, the maximum power point can be said to be the point where the voltage has the above-mentioned value and the power is maximum. In the graph of output voltage-output power characteristics, the point where the voltage is the open circuit voltage and the power is zero is defined as the open circuit voltage point. In the graph of the output voltage-output power characteristic, the straight line connecting the origin and the maximum power point is defined as the first straight line. In the graph of the output voltage-output power characteristic, the straight line connecting the maximum power point and the open circuit voltage point is defined as the second straight line. At this time, in the example of FIG. 3A, a region where the output voltage in the graph of the output voltage-output power characteristic is larger than the first value and smaller than the certain value is on the higher power side than the first straight line. A region where the output voltage in the graph of the output voltage-output power characteristic is larger than the certain value and smaller than the second value is on the higher power side than the second straight line.
　具体的には、図３Ａの例では、出力電圧－出力電力特性のグラフにおける出力電圧が０よりも大きく上記ある値よりも小さい領域が、第１直線よりも高電力側にある。出力電圧－出力電力特性のグラフにおける出力電圧が上記ある値から開放電圧までの領域が、第２直線よりも高電力側にある。 Specifically, in the example of FIG. 3A, a region where the output voltage in the graph of the output voltage-output power characteristics is larger than 0 and smaller than the above certain value is on the higher power side than the first straight line. In the graph of the output voltage-output power characteristic, the region where the output voltage is from the certain value to the open circuit voltage is on the higher power side than the second straight line.
　この例では、上記の所定範囲は、太陽光発電システム３１または３２の出力電力がピークになるときにおける太陽光発電システム３１または３２の出力電圧の±２０Ｖ以内の範囲である実機基準範囲を含む。そして、特性変換制御は、特性変換回路１００の最大電力点における出力電圧を実機基準範囲内の値に調整する。電力システム３００で用いられる太陽光発電システム３１または３２が分かっている場合、その太陽光発電システムに対するＭＰＰＴ制御を実施できるように電力システム３００を設計することができる。つまり、実機基準範囲を含むように、上記の所定範囲を設定できる。さらに、特性変換回路１００の最大電力点における出力電圧が実機基準範囲内の値に調整されるように、特性変換回路１００を設計できる。この例の電力システム３００は、設計のし易さの観点から有利である。 In this example, the above-described predetermined range includes an actual machine reference range that is within ±20 V of the output voltage of the photovoltaic power generation system 31 or 32 when the output power of the photovoltaic power generation system 31 or 32 reaches a peak. Then, the characteristic conversion control adjusts the output voltage at the maximum power point of the characteristic conversion circuit 100 to a value within the actual machine reference range. If the photovoltaic system 31 or 32 used in the power system 300 is known, the power system 300 can be designed so that MPPT control for the photovoltaic system can be implemented. That is, the above-mentioned predetermined range can be set so as to include the actual machine reference range. Furthermore, the characteristic conversion circuit 100 can be designed so that the output voltage at the maximum power point of the characteristic conversion circuit 100 is adjusted to a value within the actual machine reference range. The power system 300 of this example is advantageous from the viewpoint of ease of design.
　本実施形態では、特性変換制御は、特性変換回路１００の電気出力に基づいて実行される。このようにすれば、特性変換制御の精度を高め易い。具体的には、電気出力は、特性変換回路１００の出力電圧および出力電流である。 In the present embodiment, the characteristic conversion control is executed based on the electric output of the characteristic conversion circuit 100. By doing so, it is easy to improve the accuracy of the characteristic conversion control. Specifically, the electric output is the output voltage and output current of the characteristic conversion circuit 100.
　本実施形態では、特性変換制御は、第１フィードバック制御および第２フィードバック制御を含む。第１フィードバック制御は、特性変換回路１００の出力電流が相対的に小さいときに行われる制御である。第２フィードバック制御は、特性変換回路１００の出力電流が相対的に大きいときに行われる制御である。第１フィードバック制御と第２フィードバック制御とが切り替わるときに、特性変換回路１００の出力電圧が上記ある値となる。 In the present embodiment, the characteristic conversion control includes the first feedback control and the second feedback control. The first feedback control is control performed when the output current of the characteristic conversion circuit 100 is relatively small. The second feedback control is control performed when the output current of the characteristic conversion circuit 100 is relatively large. When the first feedback control and the second feedback control are switched, the output voltage of the characteristic conversion circuit 100 has the above-mentioned certain value.
　具体的には、第１フィードバック制御は、特性変換回路１００の出力電流が相対的に小さく出力電圧が相対的に大きいときに行われる。第１フィードバック制御は、特性変換回路１００の出力電圧が大きくなるほど特性変換回路１００の出力電流を小さくする。第１フィードバック制御は、特性変換回路１００の出力電圧が大きくなるほど特性変換回路１００の出力電力を小さくする。第２フィードバック制御は、特性変換回路１００の出力電流が相対的に大きく出力電圧が相対的に小さいときに行われる。第２フィードバック制御は、特性変換回路１００の出力電圧が大きくなるほど特性変換回路１００の出力電流を小さくする。第２フィードバック制御は、特性変換回路１００の出力電圧が大きくなるほど特性変換回路１００の出力電力を大きくする。このような第１フィードバック制御および第２フィードバック制御によれば、上記出力電圧－出力電力特性および出力電圧－出力電流特性を実現できる。なお、図３Ａにおいて、一点鎖線は、第１フィードバック制御の寄与を表す。二点鎖線は、第２フィードバック制御の寄与を表す。 Specifically, the first feedback control is performed when the output current of the characteristic conversion circuit 100 is relatively small and the output voltage is relatively large. In the first feedback control, the output current of the characteristic conversion circuit 100 decreases as the output voltage of the characteristic conversion circuit 100 increases. The first feedback control reduces the output power of the characteristic conversion circuit 100 as the output voltage of the characteristic conversion circuit 100 increases. The second feedback control is performed when the output current of the characteristic conversion circuit 100 is relatively large and the output voltage is relatively small. The second feedback control reduces the output current of the characteristic conversion circuit 100 as the output voltage of the characteristic conversion circuit 100 increases. The second feedback control increases the output power of the characteristic conversion circuit 100 as the output voltage of the characteristic conversion circuit 100 increases. According to the first feedback control and the second feedback control as described above, the output voltage-output power characteristic and the output voltage-output current characteristic can be realized. In FIG. 3A, the alternate long and short dash line represents the contribution of the first feedback control. The chain double-dashed line represents the contribution of the second feedback control.
　特性変換回路は、以下の特徴；第１フィードバック制御では、第２フィードバック制御に比べ、出力電圧－出力電流特性における出力電圧の増加に対する出力電流の減少の比率が大きい、および／または、第２フィードバック制御に比べ、出力電圧－出力電流特性における出力電流の増加に対する出力電圧の減少の比率が小さい、という特徴を有していてもよい。このようにすれば、特性変換回路１００の出力特性を太陽光発電システムの出力特性に近づけ易い。なお、この特徴は、後述する図１８および図１９に示されているような、第１フィードバック制御において出力電流が変化しても出力電圧が変化しない形態を含む概念である。 The characteristic conversion circuit has the following features; in the first feedback control, the ratio of the decrease in the output current to the increase in the output voltage in the output voltage-output current characteristic is larger than that in the second feedback control, and/or the second feedback control. It may have a feature that the ratio of the decrease of the output voltage to the increase of the output current in the output voltage-output current characteristic is smaller than that of the control. With this configuration, the output characteristic of the characteristic conversion circuit 100 can easily approach the output characteristic of the photovoltaic power generation system. Note that this feature is a concept including a mode in which the output voltage does not change even when the output current changes in the first feedback control, as shown in FIGS. 18 and 19 described later.
　図３Ａの例では、第１フィードバック制御では、第２フィードバック制御に比べ、出力電圧－出力電流特性における出力電圧の増加に対する出力電流の減少の比率が大きい。また、図３Ａの例では、第１フィードバック制御では、第２フィードバック制御に比べ、出力電圧－出力電流特性における出力電流の増加に対する出力電圧の減少の比率が小さい。 In the example of FIG. 3A, in the first feedback control, the ratio of the decrease in the output current to the increase in the output voltage in the output voltage-output current characteristic is larger than that in the second feedback control. Further, in the example of FIG. 3A, in the first feedback control, the ratio of the decrease in the output voltage to the increase in the output current in the output voltage-output current characteristic is smaller than that in the second feedback control.
　本実施形態では、第１フィードバック制御により、特性変換回路１００の開放電圧が制御される。 In the present embodiment, the open circuit voltage of the characteristic conversion circuit 100 is controlled by the first feedback control.
　図１および図２に戻って、本実施形態では、直流電力変換装置２０は、第１ＤＣＤＣコンバータ２１、第２ＤＣＤＣコンバータ２２および第３ＤＣＤＣコンバータ２３を有する。第１ＤＣＤＣコンバータ２１は、ＭＰＰＴ制御によって、特性変換回路１００の出力電圧を変化させる。第２ＤＣＤＣコンバータ２２は、ＭＰＰＴ制御によって、第１太陽光発電システム３１の出力電圧を変化させる。第３ＤＣＤＣコンバータ２３は、ＭＰＰＴ制御によって、第２太陽光発電システム３２の出力電圧を変化させる。このように、この例では、太陽光発電システム３１および３２ならびに特性変換回路１００を個別にＭＰＰＴ制御するマルチストリング型の直流電力変換装置２０が実現されている。ただし、直流電力変換装置は、これらを一括してＭＰＰＴ制御する集中型のものであってもよい。 Returning to FIG. 1 and FIG. 2, in the present embodiment, the DC power conversion device 20 has a first DCDC converter 21, a second DCDC converter 22 and a third DCDC converter 23. The first DCDC converter 21 changes the output voltage of the characteristic conversion circuit 100 by MPPT control. The second DCDC converter 22 changes the output voltage of the first photovoltaic power generation system 31 by MPPT control. The third DCDC converter 23 changes the output voltage of the second solar power generation system 32 by MPPT control. As described above, in this example, the multi-string type DC power conversion device 20 that individually controls the photovoltaic power generation systems 31 and 32 and the characteristic conversion circuit 100 by MPPT is realized. However, the DC power converter may be a centralized type that collectively performs MPPT control.
　図４に、特性変換回路１００の一例を示す。図４の特性変換回路１００では、電圧電流制御回路１６０と、第１フィードバック回路１１０と、第２フィードバック回路１２０と、フィードバック電流供給部１３０と、が設けられている。 FIG. 4 shows an example of the characteristic conversion circuit 100. The characteristic conversion circuit 100 of FIG. 4 includes a voltage/current control circuit 160, a first feedback circuit 110, a second feedback circuit 120, and a feedback current supply unit 130.
　第１フィードバック回路１１０は、第１抵抗１１１と、第２抵抗１１２と、第３抵抗１１３と、第１シャントレギュレータ１１５と、電流センサ１２８と、を有する。第２フィードバック回路１２０は、第４抵抗１２１と、第５抵抗１２２と、第６抵抗１２３と、第２シャントレギュレータ１２５と、電流センサ１２８と、を有する。電流センサ１２８は、第１フィードバック回路１１０および第２フィードバック回路１２０によって共有されている。フィードバック電流供給部１３０は、電流供給電源１３１と、第７抵抗１３２と、を有する。本実施形態では、電流供給電源１３１は、定電圧源である。 The first feedback circuit 110 has a first resistor 111, a second resistor 112, a third resistor 113, a first shunt regulator 115, and a current sensor 128. The second feedback circuit 120 has a fourth resistor 121, a fifth resistor 122, a sixth resistor 123, a second shunt regulator 125, and a current sensor 128. The current sensor 128 is shared by the first feedback circuit 110 and the second feedback circuit 120. The feedback current supply unit 130 has a current supply power supply 131 and a seventh resistor 132. In the present embodiment, the current supply power source 131 is a constant voltage source.
　電流センサ１２８は、特性変換回路１００の出力電流の検出を行う。本実施形態では、電流センサ１２８は、その検出の結果を表すセンサ出力を出力する。電流センサ１２８は、特性変換回路１００の出力電流が大きくなるほどセンサ出力を大きく出力する。つまり、センサ出力は、特性変換回路１００の出力電流が大きくなるほど大きくなる。そのような電流センサ１２８は、例えば、シャント抵抗を用いて実現できる。電流センサ１２８が出力したセンサ出力は、接続点ｐｓへと供給される。具体的には、センサ出力は、センサ電圧Ｖsである。また、電流センサ１２８は、センサ電圧Ｖsを出力するセンサ出力部１２８ａを含む。 The current sensor 128 detects the output current of the characteristic conversion circuit 100. In the present embodiment, the current sensor 128 outputs a sensor output indicating the result of the detection. The current sensor 128 outputs a larger sensor output as the output current of the characteristic conversion circuit 100 increases. That is, the sensor output increases as the output current of the characteristic conversion circuit 100 increases. Such a current sensor 128 can be realized by using a shunt resistor, for example. The sensor output output from the current sensor 128 is supplied to the connection point ps. Specifically, the sensor output is the sensor voltage V s . The current sensor 128 also includes a sensor output unit 128a that outputs the sensor voltage V s .
　図５に、具体例に係る電流センサ１２８を示す。電流センサ１２８は、シャント抵抗１２８ｒと、電流センスアンプ１２８ｓと、を含む。シャント抵抗１２８ｒの抵抗値は、Ｒsenseである。シャント抵抗１２８ｒに電流Ｉloadが流れると、シャント抵抗１２８ｒに電圧ＲsenseＩloadがかかる。電流センスアンプ１２８ｓは、電圧ＲsenseＩloadにゲインＧを乗じた電圧と、バイアス電圧Ｖbiasと、の合計電圧を、センサ電圧Ｖsとして出力する。つまり、本実施形態の電流センサ１２８が生成するセンサ電圧Ｖsは、数式１で与えられる。ただし、電流センサ１２８としてホール素子方式の電流センサ等の他の電流センサを用い、その電流センサの出力をセンサ電圧Ｖsとして用いてもよい。なお、電流Ｉloadは、特性変換回路１００の出力電流に対応する。「＊」は、乗算を表す記号である。
　　数式１：Ｖs＝Ｒsense＊Ｉload＊Ｇ＋Ｖbias FIG. 5 shows a current sensor 128 according to a specific example. The current sensor 128 includes a shunt resistor 128r and a current sense amplifier 128s. The resistance value of the shunt resistor 128r is R sense . When the current I load flows through the shunt resistor 128r, the voltage R sense I load is applied to the shunt resistor 128r. The current sense amplifier 128s outputs the total voltage of the voltage obtained by multiplying the voltage R sense I load by the gain G and the bias voltage V bias as the sensor voltage V s . That is, the sensor voltage V s generated by the current sensor 128 of the present embodiment is given by Equation 1. However, another current sensor such as a Hall element type current sensor may be used as the current sensor 128, and the output of the current sensor may be used as the sensor voltage V s . The current I load corresponds to the output current of the characteristic conversion circuit 100. "*" is a symbol representing multiplication.
Formula 1: V s =R sense *I load *G+V bias
　第１フィードバック回路１１０では、第１抵抗１１１および第２抵抗１１２により、特性変換回路１００の出力電圧Ｖoutが分圧される。第３抵抗１１３および第２抵抗１１２により、センサ電圧Ｖsが分圧される。これら２つの分圧電圧を合算した電圧が、３つの抵抗１１１、１１２および１１３の接続点ｐ１に現れる。以下、第１接続点ｐ１に現れる電圧を、第１参照電圧Ｖref1と称することがある。第１参照電圧Ｖref1が、第１シャントレギュレータ１１５の第１参照電圧端子に入力される。第１参照電圧端子に入力される電圧が大きいほど、電流供給電源１３１、第７抵抗１３２、第１シャントレギュレータ１１５および基準電位をこの順に流れる電流（以下、第１電流と称することがある）ｉ１は、大きくなる。図４において、第１電流ｉ１は、第１シャントレギュレータ１１５を図示下向きに流れる電流である。 In the first feedback circuit 110, the output voltage V out of the characteristic conversion circuit 100 is divided by the first resistor 111 and the second resistor 112. The sensor voltage V s is divided by the third resistor 113 and the second resistor 112. A voltage obtained by adding these two divided voltages appears at the connection point p1 of the three resistors 111, 112, and 113. Hereinafter, the voltage appearing at the first connection point p1 may be referred to as a first reference voltage V ref1 . The first reference voltage V ref1 is input to the first reference voltage terminal of the first shunt regulator 115. The larger the voltage input to the first reference voltage terminal is, the more the current that flows through the current supply power supply 131, the seventh resistor 132, the first shunt regulator 115, and the reference potential in this order (hereinafter, may be referred to as the first current) i1. Grows. In FIG. 4, the first current i1 is a current flowing downward in the first shunt regulator 115 in the drawing.
　第２フィードバック回路１２０では、第４抵抗１２１および第５抵抗１２２により、特性変換回路１００の出力電圧Ｖoutが分圧される。第６抵抗１２３および第５抵抗１２２により、センサ電圧Ｖsが分圧される。これら２つの分圧電圧を合算した電圧が、３つの抵抗１２１，１２２および１２３の接続点ｐ２に現れる。以下、第２接続点ｐ２に現れる電圧を、第２参照電圧Ｖref2と称することがある。第２参照電圧Ｖref2が、第２シャントレギュレータ１２５の第２参照電圧端子に入力される。第２参照電圧端子に入力される電圧が大きいほど、電流供給電源１３１、第７抵抗１３２、第２シャントレギュレータ１２５および基準電位をこの順に流れる電流（以下、第２電流と称することがある）ｉ２は、大きくなる。図４において、第２電流ｉ２は、第２シャントレギュレータ１２５を図示下向きに流れる電流である。 In the second feedback circuit 120, the output voltage V out of the characteristic conversion circuit 100 is divided by the fourth resistor 121 and the fifth resistor 122. The sensor voltage V s is divided by the sixth resistor 123 and the fifth resistor 122. A voltage obtained by adding these two divided voltages appears at the connection point p2 of the three resistors 121, 122 and 123. Hereinafter, the voltage appearing at the second connection point p2 may be referred to as the second reference voltage V ref2 . The second reference voltage V ref2 is input to the second reference voltage terminal of the second shunt regulator 125. The larger the voltage input to the second reference voltage terminal, the more the current that flows through the current supply power supply 131, the seventh resistor 132, the second shunt regulator 125, and the reference potential in this order (hereinafter, may be referred to as the second current) i2. Grows. In FIG. 4, the second current i2 is a current flowing downward in the second shunt regulator 125 in the drawing.
　特性変換回路１００の出力電流が小さい領域では、第２電流ｉ２は実質的にゼロとなり、電流供給電源１３１から流出する電流は、実質的に第１電流ｉ１である。一方、特性変換回路１００の出力電流が大きい領域では、第１電流ｉ１は実質的にゼロとなり、電流供給電源１３１から流出する電流は、実質的に第２電流ｉ２である。つまり、特性変換回路１００の出力電流が小さい領域では第１フィードバック回路１１０によって、特性変換回路１００の出力電流が大きい領域では第２フィードバック回路１２０によって、特性変換回路１００における特性変換が行われると言える。そのように回路１１０および１２０が動作するように、抵抗１１１，１１２，１１３，１２１，１２２および１２３ならびにシャントレギュレータ１１５および１２５のパラメータが選定されている。 In a region where the output current of the characteristic conversion circuit 100 is small, the second current i2 becomes substantially zero, and the current flowing out from the current supply power source 131 is substantially the first current i1. On the other hand, in a region where the output current of the characteristic conversion circuit 100 is large, the first current i1 becomes substantially zero, and the current flowing out from the current supply power source 131 is substantially the second current i2. That is, it can be said that the characteristic conversion circuit 100 performs the characteristic conversion by the first feedback circuit 110 in the region where the output current of the characteristic conversion circuit 100 is small, and by the second feedback circuit 120 in the region where the output current of the characteristic conversion circuit 100 is large. .. The parameters of the resistors 111, 112, 113, 121, 122 and 123 and the shunt regulators 115 and 125 are selected so that the circuits 110 and 120 operate as described above.
　本実施形態では、特性変換回路１００の出力特性は、特性変換回路１００に含まれたアナログ回路によって定められていると言える。ここで、出力特性は、出力電流と、出力電圧と、出力電力と、の関係と考えることができる。具体的には、特性変換回路１００の出力特性は、特性変換回路１００に含まれたアナログ回路の回路定数よって定められていると言える。ここで、回路定数は、抵抗の抵抗値等を指す。 In the present embodiment, it can be said that the output characteristic of the characteristic conversion circuit 100 is determined by the analog circuit included in the characteristic conversion circuit 100. Here, the output characteristic can be considered as a relationship among the output current, the output voltage, and the output power. Specifically, it can be said that the output characteristic of the characteristic conversion circuit 100 is determined by the circuit constant of the analog circuit included in the characteristic conversion circuit 100. Here, the circuit constant refers to the resistance value of the resistor or the like.
　電圧電流制御回路１６０は、ＤＣＤＣコンバータである。電圧電流制御回路１６０は、電流供給電源１３１から流出する電流が大きいほど、電圧電流制御回路１６０の入力電圧に対する出力電圧の比率を小さくする。このように、特性変換回路１００は、電流供給電源１３１から流出する電流に応じて上記比率が調整されるようになっている。このような特性変換回路１００は、適宜設計可能である。 The voltage/current control circuit 160 is a DCDC converter. The voltage/current control circuit 160 reduces the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 as the current flowing out from the current supply power source 131 is larger. As described above, in the characteristic conversion circuit 100, the ratio is adjusted according to the current flowing out from the current supply power source 131. Such a characteristic conversion circuit 100 can be designed as appropriate.
　図６を参照して、本実施形態の第１シャントレギュレータ１１５についてさらに説明する。第１シャントレギュレータ１１５は、第１参照電圧端子１１５ａと、第１カソード１１５Ｋと、第１アノード１１５Ａと、第１基準電圧源１１５ｓと、第１オペアンプ１１５оと、第１トランジスタ１１５ｔと、を含む。第１オペアンプ１１５оは、非反転増幅端子１１５оａと、反転増幅端子１１５оｂと、出力端子１１５оｃと、を含む。第１トランジスタ１１５ｔは、カソード側端子１１５ｔａと、アノード側端子１１５ｔｂと、制御端子１１５ｔｃと、を含む。非反転増幅端子１１５оａには、第１参照電圧端子１１５ａに入力された電圧が供給される。反転増幅端子１１５оｂの電圧は、第１基準電圧源１１５ｓによって、第１アノード１１５Ａの電圧よりも第１基準電圧Ｖs1だけ高い電圧に設定されている。第１参照電圧端子１１５ａに第１基準電圧Ｖs1よりも大きい電圧が入力されることによって非反転増幅端子１１５оａの電圧が反転増幅端子１１５оｂよりも電圧が大きくなると、出力端子１１５оｃから制御端子１１５ｔｃに電流が流れ、第１カソード１１５Ｋからカソード側端子１１５ｔａおよびアノード側端子１１５ｔｂをこの順に介して第１アノード１１５Ａへと第１電流ｉ１が流れる。図６の例では、第１トランジスタ１１５ｔは、バイポーラトランジスタであり、具体的にはＮＰＮトランジスタである。カソード側端子１１５ｔａは、コレクタである。アノード側端子１１５ｔｂは、エミッタである。制御端子１１５ｔｃは、ベースである。なお、この説明では、出力端子１１５оｃと制御端子１１５ｔｃの間で流れる電流、具体的にはベース電流、は十分に小さいものとして無視している。 The first shunt regulator 115 of this embodiment will be further described with reference to FIG. 6. The first shunt regulator 115 includes a first reference voltage terminal 115a, a first cathode 115K, a first anode 115A, a first reference voltage source 115s, a first operational amplifier 115o, and a first transistor 115t. The first operational amplifier 115o includes a non-inverting amplification terminal 115oa, an inverting amplification terminal 115ob, and an output terminal 115oc. The first transistor 115t includes a cathode side terminal 115ta, an anode side terminal 115tb, and a control terminal 115tc. The voltage input to the first reference voltage terminal 115a is supplied to the non-inverting amplification terminal 115a. Voltage of the inverting amplifier terminal 115оb is the first reference voltage source 115s, is set to a high voltage by the first reference voltage V s1 than the voltage of the first anode 115A. When a voltage larger than the first reference voltage V s1 is input to the first reference voltage terminal 115a and the voltage of the non-inverting amplification terminal 115оa becomes larger than the voltage of the inverting amplification terminal 115оb, the output terminal 115оc changes to the control terminal 115tc. A current flows, and the first current i1 flows from the first cathode 115K to the first anode 115A through the cathode side terminal 115ta and the anode side terminal 115tb in this order. In the example of FIG. 6, the first transistor 115t is a bipolar transistor, specifically an NPN transistor. The cathode side terminal 115ta is a collector. The anode side terminal 115tb is an emitter. The control terminal 115tc is the base. In this description, the current flowing between the output terminal 115c and the control terminal 115tc, specifically the base current, is ignored because it is sufficiently small.
　図６を参照した説明を踏まえて、第１フィードバック回路１１０の動作を以下のように説明できる。特性変換回路１００の出力電圧Ｖoutが大きくなると、また、特性変換回路１００の出力電流が大きくなってセンサ電圧Ｖsが大きくなると、第１参照電圧Ｖref1は大きくなる。第１シャントレギュレータ１２５では、第１参照電圧Ｖref1が大きくなることにより第１参照電圧Ｖref1の第１基準電圧Ｖs1からの乖離が大きくなればなるほど、第１電流ｉ１が大きくなる。第１電流ｉ１が大きくなると、電流供給電源１３１から流出する電流が大きくなる。この流出電流が大きくなると、電圧電流制御回路１６０の入力電圧に対する出力電圧の比率は小さくなる。このようにして、第１フィードバック回路１１０は、特性変換回路１００の出力電圧Ｖoutを制御する。具体的には、第１フィードバック回路１１０は、第１参照電圧Ｖref1が第１基準電圧Ｖs1に追従するように、特性変換回路１００の変圧比を調節する。 Based on the description with reference to FIG. 6, the operation of the first feedback circuit 110 can be described as follows. When the output voltage V out of the characteristic conversion circuit 100 increases, and when the output current of the characteristic conversion circuit 100 increases and the sensor voltage V s increases, the first reference voltage V ref1 increases. In the first shunt regulator 125, the greater the deviation from the first reference voltage V s1 of the first reference voltage V ref1 by the first reference voltage V ref1 is increased, the first current i1 increases. As the first current i1 increases, the current flowing out of the current supply power source 131 also increases. When this outflow current increases, the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 decreases. In this way, the first feedback circuit 110 controls the output voltage V out of the characteristic conversion circuit 100. Specifically, the first feedback circuit 110 adjusts the transformation ratio of the characteristic conversion circuit 100 so that the first reference voltage V ref1 follows the first reference voltage V s1 .
　第１フィードバック回路１１０による第１フィードバック制御において、特性変換回路１００の出力電流が大きくなりセンサ電圧Ｖsが大きくなると、電流センサ１２８から接続点ｐｓおよび第３抵抗１１３をこの順に介して第１接続点ｐ１に流れる電流が大きくなる。第１シャントレギュレータ１１５により、第１参照電圧Ｖref1は、一定の第１基準電圧Ｖs１に追従する。この追従を実現するために、第２抵抗１１２には、一定の電流が流れる。このことは、第３抵抗１１３を第１接続点ｐ１に向かって流れる上記電流が大きくなると、第１抵抗１１１を第１接続点ｐ１に向かって流れる電流が小さくなることを意味する。この電流が小さくなると、第１抵抗１１１で生じる電圧が小さくなる。このような理由で、特性変換回路１００の出力電流が大きくなると、第１接続点ｐ１の電圧が第１参照電圧Ｖref1に追従した状態で第１抵抗１１１において生じる電圧が小さくなる。その結果、特性変換回路１００の出力電圧Ｖoutが小さくなる。このようにして、第１フィードバック制御により、図３Ａに示すような、特性変換回路１００の出力電圧が大きくなるほど特性変換回路１００の出力電流が小さくなる出力電圧－出力電流特性が得られる。 In the first feedback control by the first feedback circuit 110, when the output current of the characteristic conversion circuit 100 increases and the sensor voltage V s increases, the current sensor 128 makes the first connection via the connection point ps and the third resistor 113 in this order. The current flowing at the point p1 becomes large. The first shunt regulator 115 causes the first reference voltage V ref1 to follow the constant first reference voltage V s1 . In order to realize this tracking, a constant current flows through the second resistor 112. This means that when the current flowing through the third resistor 113 toward the first connection point p1 increases, the current flowing through the first resistor 111 toward the first connection point p1 decreases. When this current decreases, the voltage generated in the first resistor 111 decreases. For this reason, when the output current of the characteristic conversion circuit 100 increases, the voltage generated in the first resistor 111 decreases with the voltage at the first connection point p1 following the first reference voltage V ref1 . As a result, the output voltage V out of the characteristic conversion circuit 100 decreases. In this way, by the first feedback control, as shown in FIG. 3A, an output voltage-output current characteristic in which the output current of the characteristic conversion circuit 100 decreases as the output voltage of the characteristic conversion circuit 100 increases is obtained.
　図７を参照して、本実施形態の第２シャントレギュレータ１２５についてさらに説明する。第２シャントレギュレータ１２５は、第２参照電圧端子１２５ａと、第２カソード１２５Ｋと、第２アノード１２５Ａと、第２基準電圧源１２５ｓと、第２オペアンプ１２５оと、第２トランジスタ１２５ｔと、を含む。第２オペアンプ１２５оは、非反転増幅端子１２５оａと、反転増幅端子１２５оｂと、出力端子１２５оｃと、を含む。第２トランジスタ１２５ｔは、カソード側端子１２５ｔａと、アノード側端子１２５ｔｂと、制御端子１２５ｔｃと、を含む。非反転増幅端子１２５оａには、第２参照電圧端子１２５ａに入力された電圧が供給される。反転増幅端子１２５оｂの電圧は、第２基準電圧源１２５ｓによって、第２アノード１２５Ａの電圧よりも第２基準電圧Ｖs2だけ高い電圧に設定されている。第２参照電圧端子１２５ａに第２基準電圧Ｖs2よりも大きい電圧が入力されることによって非反転増幅端子１２５оａの電圧が反転増幅端子１２５оｂよりも電圧が大きくなると、出力端子１２５оｃから制御端子１２５ｔｃに電流が流れ、第２カソード１２５Ｋからカソード側端子１２５ｔａおよびアノード側端子１２５ｔｂをこの順に介して第２アノード１２５Ａへと第２電流ｉ２が流れる。図７の例では、第２トランジスタ１２５ｔは、バイポーラトランジスタであり、具体的にはＮＰＮトランジスタである。カソード側端子１２５ｔａは、コレクタである。アノード側端子１２５ｔｂは、エミッタである。制御端子１２５ｔｃは、ベースである。なお、この説明では、出力端子１２５оｃと制御端子１２５ｔｃの間で流れる電流、具体的にはベース電流、は十分に小さいものとして無視している。 The second shunt regulator 125 of this embodiment will be further described with reference to FIG. 7. The second shunt regulator 125 includes a second reference voltage terminal 125a, a second cathode 125K, a second anode 125A, a second reference voltage source 125s, a second operational amplifier 125o, and a second transistor 125t. The second operational amplifier 125о includes a non-inverting amplifier terminal 125оa, an inverting amplifier terminal 125оb, and an output terminal 125оc. The second transistor 125t includes a cathode side terminal 125ta, an anode side terminal 125tb, and a control terminal 125tc. The voltage input to the second reference voltage terminal 125a is supplied to the non-inverting amplification terminal 125a. Voltage of the inverting amplifier terminal 125оb is the second reference voltage source 125s, is set to a high voltage by the second reference voltage V s2 than the voltage of the second anode 125A. When a voltage higher than the second reference voltage V s2 is input to the second reference voltage terminal 125a and the voltage of the non-inverting amplification terminal 125оa becomes higher than the voltage of the inverting amplification terminal 125оb, the output terminal 125оc changes to the control terminal 125tc. A current flows, and the second current i2 flows from the second cathode 125K to the second anode 125A through the cathode side terminal 125ta and the anode side terminal 125tb in this order. In the example of FIG. 7, the second transistor 125t is a bipolar transistor, specifically, an NPN transistor. The cathode side terminal 125ta is a collector. The anode side terminal 125tb is an emitter. The control terminal 125tc is the base. In this description, the current flowing between the output terminal 125c and the control terminal 125tc, specifically the base current, is neglected as being sufficiently small.
　図７を参照した説明を踏まえて、第２フィードバック回路１２０の動作を以下のように説明できる。特性変換回路１００の出力電圧Ｖoutが大きくなると、また、特性変換回路１００の出力電流が大きくなってセンサ電圧Ｖsが大きくなると、第２参照電圧Ｖref2は大きくなる。第２シャントレギュレータ１２５では、第２参照電圧Ｖref2が大きくなることにより第２参照電圧Ｖref2の第２基準電圧Ｖs2からの乖離が大きくなればなるほど、第２電流ｉ２が大きくなる。第２電流ｉ２が大きくなると、電流供給電源１３１から流出する電流が大きくなる。この流出電流が大きくなると、電圧電流制御回路１６０の入力電圧に対する出力電圧の比率は小さくなる。このようにして、第２フィードバック回路１２０は、特性変換回路１００の出力電圧Ｖoutを制御する。具体的には、第２フィードバック回路１２０は、第２参照電圧Ｖref2が第２基準電圧Ｖs2に追従するように、特性変換回路１００の変圧比を調節する。 Based on the description with reference to FIG. 7, the operation of the second feedback circuit 120 can be described as follows. If the output voltage V out of the characteristic conversion circuit 100 increases, or if the output current of the characteristic conversion circuit 100 increases and the sensor voltage V s increases, the second reference voltage V ref2 increases. In the second shunt regulator 125, the greater the deviation from the second reference voltage V s2 of the second reference voltage V ref2 by the second reference voltage V ref2 is increased, the second current i2 is large. When the second current i2 increases, the current flowing out of the current supply power source 131 also increases. When this outflow current increases, the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 decreases. In this way, the second feedback circuit 120 controls the output voltage V out of the characteristic conversion circuit 100. Specifically, the second feedback circuit 120 adjusts the transformation ratio of the characteristic conversion circuit 100 so that the second reference voltage V ref2 follows the second reference voltage V s2 .
　第２フィードバック回路１２０による第２フィードバック制御において、特性変換回路１００の出力電流が大きくなりセンサ電圧Ｖsが大きくなると、電流センサ１２８から接続点ｐｓおよび第６抵抗１２３をこの順に介して第２接続点ｐ２に流れる電流が大きくなる。第２シャントレギュレータ１２５により、第２参照電圧Ｖref2は、一定の第２基準電圧Ｖs2に追従する。この追従を実現するために、第５抵抗１２２には、一定の電流が流れる。このことは、第６抵抗１２３を第２接続点ｐ２に向かって流れる上記電流が大きくなると、第４抵抗１２１を第２接続点ｐ２に向かって流れる電流が小さくなることを意味する。この電流が小さくなると、第４抵抗１２１で生じる電圧が小さくなる。このような理由で、特性変換回路１００の出力電流が大きくなると、第２接続点ｐ２の電圧が第２参照電圧Ｖref2に追従した状態で第４抵抗１２１において生じる電圧が小さくなる。その結果、特性変換回路１００の出力電圧Ｖoutが小さくなる。このようにして、第２フィードバック制御により、図３Ａに示すような、特性変換回路１００の出力電圧が大きくなるほど特性変換回路１００の出力電流が小さくなる出力電圧－出力電流特性が得られる。 In the second feedback control by the second feedback circuit 120, when the output current of the characteristic conversion circuit 100 increases and the sensor voltage V s increases, the current sensor 128 makes the second connection via the connection point ps and the sixth resistor 123 in this order. The current flowing at the point p2 becomes large. The second shunt regulator 125 causes the second reference voltage V ref2 to follow the constant second reference voltage V s2 . In order to realize this tracking, a constant current flows through the fifth resistor 122. This means that when the current flowing through the sixth resistor 123 toward the second connection point p2 increases, the current flowing through the fourth resistor 121 toward the second connection point p2 decreases. When this current decreases, the voltage generated in the fourth resistor 121 decreases. For this reason, when the output current of the characteristic conversion circuit 100 increases, the voltage generated in the fourth resistor 121 decreases with the voltage at the second connection point p2 following the second reference voltage V ref2 . As a result, the output voltage V out of the characteristic conversion circuit 100 decreases. In this way, by the second feedback control, as shown in FIG. 3A, an output voltage-output current characteristic in which the output current of the characteristic conversion circuit 100 becomes smaller as the output voltage of the characteristic conversion circuit 100 becomes larger is obtained.
　上述の説明から理解されるように、本実施形態では、特性変換回路１００は、電流センサ１２８と、少なくとも１つの分圧抵抗と、ＤＣＤＣコンバータである電圧電流制御回路１６０と、を含む。特性変換回路１００は、電流センサ１２８を用いて、特性変換回路１００の出力電流を特性変換制御に反映させる。特性変換回路１００は、少なくとも１つの分圧抵抗を用いて、特性変換回路１００の出力電圧を特性変換制御に反映させる。特性変換回路１００は、特性変換制御によって、電圧電流制御回路１６０の変圧比を調整する。図４の例では、少なくとも１つの分圧抵抗は、第１分圧抵抗と第２分圧抵抗とを含む。第１分圧抵抗は、第１抵抗１１１および第２抵抗１１２によって構成されている。第２分圧抵抗は、第４抵抗１２１および第５抵抗１２２によって構成されている。 As can be understood from the above description, in the present embodiment, the characteristic conversion circuit 100 includes the current sensor 128, at least one voltage dividing resistor, and the voltage/current control circuit 160 that is a DCDC converter. The characteristic conversion circuit 100 uses the current sensor 128 to reflect the output current of the characteristic conversion circuit 100 in the characteristic conversion control. The characteristic conversion circuit 100 uses at least one voltage dividing resistor to reflect the output voltage of the characteristic conversion circuit 100 in the characteristic conversion control. The characteristic conversion circuit 100 adjusts the transformation ratio of the voltage/current control circuit 160 by characteristic conversion control. In the example of FIG. 4, the at least one voltage dividing resistor includes a first voltage dividing resistor and a second voltage dividing resistor. The first voltage dividing resistor includes a first resistor 111 and a second resistor 112. The second voltage dividing resistor includes a fourth resistor 121 and a fifth resistor 122.
　本実施形態では、具体的には、特性変換回路１００において、ＤＣＤＣコンバータである電圧電流制御回路１６０と、第１フィードバック制御を行う第１フィードバック回路１１０と、第２フィードバック制御を行う第２フィードバック回路１２０と、が設けられている。第１フィードバック回路１１０は、特性変換回路１００の出力電流および出力電圧に応じて変化する第１参照電圧Ｖref1が入力される第１シャントレギュレータ１１５を有する。第２フィードバック回路１２０は、特性変換回路１００の出力電流および出力電圧に応じて変化する第２参照電圧Ｖref2が入力される第２シャントレギュレータ１２５を有する。第１フィードバック制御おいて、第１シャントレギュレータ１１５を用いて第１参照電圧Ｖref1が一定に維持されるように電圧電流制御回路１６０の変圧比が調整される。第２フィードバック制御おいて、第２シャントレギュレータ１２５を用いて第２参照電圧Ｖref2が一定に維持されるように電圧電流制御回路１６０の変圧比が調整される。 In the present embodiment, specifically, in the characteristic conversion circuit 100, a voltage/current control circuit 160 that is a DCDC converter, a first feedback circuit 110 that performs first feedback control, and a second feedback circuit that performs second feedback control. 120 are provided. The first feedback circuit 110 has a first shunt regulator 115 to which the first reference voltage V ref1 that changes according to the output current and the output voltage of the characteristic conversion circuit 100 is input. The second feedback circuit 120 has a second shunt regulator 125 to which the second reference voltage V ref2 that changes according to the output current and the output voltage of the characteristic conversion circuit 100 is input. In the first feedback control, the first shunt regulator 115 is used to adjust the transformation ratio of the voltage/current control circuit 160 so that the first reference voltage V ref1 is maintained constant. In the second feedback control, the transformation ratio of the voltage/current control circuit 160 is adjusted by using the second shunt regulator 125 so that the second reference voltage V ref2 is maintained constant.
　より具体的には、第１フィードバック回路は、第１分圧抵抗を有する。第２フィードバック回路は、第２分圧抵抗を有する。第１フィードバック回路１１０および第２フィードバック回路１２０は、電流センサ１２８を共有している。第１分圧抵抗は、特性変換回路１００の出力電圧を第１参照電圧Ｖref1に反映させるのに用いられる。電流センサ１２８は、特性変換回路１００の出力電流を第１参照電圧Ｖref1に反映させるのに用いられる。第２分圧抵抗は、特性変換回路１００の出力電圧を第２参照電圧Ｖref2に反映させるのに用いられる。電流センサ１２８は、特性変換回路１００の出力電流を第２参照電圧Ｖref2に反映させるのに用いられる。図４の例では、第１分圧抵抗は、第１抵抗１１１および第２抵抗１１２によって構成されている。第２分圧抵抗は、第４抵抗１２１および第５抵抗１２２によって構成されている。 More specifically, the first feedback circuit has a first voltage dividing resistor. The second feedback circuit has a second voltage dividing resistor. The first feedback circuit 110 and the second feedback circuit 120 share the current sensor 128. The first voltage dividing resistor is used to reflect the output voltage of the characteristic conversion circuit 100 on the first reference voltage V ref1 . The current sensor 128 is used to reflect the output current of the characteristic conversion circuit 100 in the first reference voltage V ref1 . The second voltage dividing resistor is used to reflect the output voltage of the characteristic conversion circuit 100 on the second reference voltage V ref2 . The current sensor 128 is used to reflect the output current of the characteristic conversion circuit 100 in the second reference voltage V ref2 . In the example of FIG. 4, the first voltage dividing resistor is composed of the first resistor 111 and the second resistor 112. The second voltage dividing resistor includes a fourth resistor 121 and a fifth resistor 122.
　また、第１フィードバック回路は、第３分圧抵抗を有する。第２フィードバック回路は、第４分圧抵抗を有する。第３分圧抵抗は、特性変換回路１００の出力電流を第１参照電圧Ｖref1に反映させるのに用いられる。第４分圧抵抗は、特性変換回路１００の出力電流を第２参照電圧Ｖref2に反映させるのに用いられる。図４の例では、第３分圧抵抗は、第３抵抗１１３および第２抵抗１１２によって構成されている。第４分圧抵抗は、第６抵抗１２３および第５抵抗１２２によって構成されている。 Further, the first feedback circuit has a third voltage dividing resistor. The second feedback circuit has a fourth voltage dividing resistor. The third voltage dividing resistor is used to reflect the output current of the characteristic conversion circuit 100 in the first reference voltage V ref1 . The fourth voltage dividing resistor is used to reflect the output current of the characteristic conversion circuit 100 in the second reference voltage V ref2 . In the example of FIG. 4, the third voltage dividing resistor is composed of the third resistor 113 and the second resistor 112. The fourth voltage dividing resistor includes a sixth resistor 123 and a fifth resistor 122.
　以上の説明から理解されるように、特性変換回路１００では、特性変換回路１００の出力電流および出力電圧がその後の特性変換回路１００の出力電流および出力電圧に反映されるという、フィードバック制御ループが構成されている。フィードバック制御ループは、フィードバック回路１１０または１２０を用いて構成されている。 As can be understood from the above description, the characteristic conversion circuit 100 has a feedback control loop in which the output current and the output voltage of the characteristic conversion circuit 100 are reflected in the output current and the output voltage of the characteristic conversion circuit 100 thereafter. Has been done. The feedback control loop is configured using the feedback circuit 110 or 120.
　図１および図２に戻って、特性変換回路１００の出力電力は、ＬＣフィルタ６１および保護リレー６２を介して、直流電力変換装置２０に、具体的には第１ＤＣＤＣコンバータ２１に、供給される。 Returning to FIG. 1 and FIG. 2, the output power of the characteristic conversion circuit 100 is supplied to the DC power conversion device 20, specifically the first DCDC converter 21, via the LC filter 61 and the protection relay 62.
［蓄電装置２５］
　上述のように、蓄電装置２５には、第４ＤＣＤＣコンバータ１２から電力が供給される。また、蓄電装置２５は、第４ＤＣＤＣコンバータ１２に電力を供給する。 [Power storage device 25]
As described above, the power storage device 25 is supplied with power from the fourth DCDC converter 12. The power storage device 25 also supplies power to the fourth DCDC converter 12.
　蓄電装置２５は、例えば、リチウム電池である。ただし、蓄電装置２５として、リチウム電池以外の電池を用いてもよい。蓄電装置２５として、キャパシタを用いてもよい。 The power storage device 25 is, for example, a lithium battery. However, a battery other than a lithium battery may be used as the power storage device 25. A capacitor may be used as the power storage device 25.
［主分電盤８０］
　主分電盤８０は、連系ブレーカー８１と、主幹ブレーカー８２と、二次連系ブレーカー８３と、第１分岐部８５と、を有する。第１分岐部８５は、複数の分岐ブレーカーを含む。この例では、第１分岐部８５は、分岐ブレーカー８５ａ，８５ｂおよび８５ｃを含む。 [Main distribution board 80]
The main distribution board 80 has an interconnection breaker 81, a main breaker 82, a secondary interconnection breaker 83, and a first branch portion 85. The first branch part 85 includes a plurality of branch breakers. In this example, the first branch portion 85 includes branch breakers 85a, 85b and 85c.
　主幹ブレーカー８２は、上流側電路８８により、系統電源２００と接続されている。上流側電路８８は、主幹ブレーカー８２を介して下流側電路８９に接続されている。 The main breaker 82 is connected to the system power supply 200 by an upstream electric line 88. The upstream electric circuit 88 is connected to the downstream electric circuit 89 via the main breaker 82.
　下流側電路８９には、二次連系ブレーカー８３が接続されている。二次連系ブレーカー８３は、主幹ブレーカー８２と第２インバータ４４とを接続する経路上に設けられている。二次連系ブレーカー８３は、第１分岐部８５と電気的に接続されている。 A secondary interconnection breaker 83 is connected to the downstream electric circuit 89. The secondary interconnection breaker 83 is provided on the path connecting the main breaker 82 and the second inverter 44. The secondary interconnection breaker 83 is electrically connected to the first branch portion 85.
　下流側電路８９には、第１分岐部８５も接続されている。第１分岐部８５の分岐ブレーカー８５ａは、主幹ブレーカー８２と電力切替ユニット２８の系統電力入力部２８ａとを接続する経路上に設けられている。分岐ブレーカー８５ｂは、主幹ブレーカー８２と第２負荷２５２とを接続する経路上に設けられている。分岐ブレーカー８５ｃは、主幹ブレーカー８２と第３負荷２５３とを接続する経路上に設けられている。 The first branch 85 is also connected to the downstream electric circuit 89. The branch breaker 85a of the first branch section 85 is provided on the path connecting the main breaker 82 and the system power input section 28a of the power switching unit 28. The branch breaker 85b is provided on the path connecting the main breaker 82 and the second load 252. The branch breaker 85c is provided on the path connecting the main breaker 82 and the third load 253.
　上流側電路８８には、第３接続点ｐ３がある。連系ブレーカー８１は、第３接続点ｐ３と第１インバータ１３とを接続する経路上に設けられている。 The upstream electric circuit 88 has a third connection point p3. The interconnection breaker 81 is provided on the path connecting the third connection point p3 and the first inverter 13.
　この例では、系統電源２００から第３接続点ｐ３を介して主幹ブレーカー８２に電圧ＶAC2の交流電力が供給され得る。系統電源２００から第３接続点ｐ３および連系ブレーカー８１をこの順に介して第１インバータ１３に電圧ＶAC2の交流電力が供給され得る。第１インバータ１３から連系ブレーカー８１および第３接続点ｐ３をこの順に介して系統電源２００に電圧ＶAC2の交流電力が逆潮流され得る。第１インバータ１３から連系ブレーカー８１および第３接続点ｐ３をこの順に介して主幹ブレーカー８２に電圧ＶAC2の交流電力が供給され得る。二次連系ブレーカー８３には、第２インバータ４４から電圧ＶAC2の交流電力が供給され得る。分岐ブレーカー８５ａから電力切替ユニット２８に電圧ＶAC1の交流電力が供給され得る。分岐ブレーカー８５ｂから第２負荷２５２に電圧ＶAC1の交流電力が供給され得る。分岐ブレーカー８５ｃから第３負荷２５３に電圧ＶAC2の交流電力が供給され得る。 In this example, AC power of voltage V AC2 can be supplied from the system power supply 200 to the main breaker 82 via the third connection point p3. AC power of voltage V AC2 can be supplied from the system power supply 200 to the first inverter 13 via the third connection point p3 and the interconnection breaker 81 in this order. From the first inverter 13, AC power of voltage V AC2 can be reversely flowed to the system power supply 200 via the interconnection breaker 81 and the third connection point p3 in this order. AC power of voltage V AC2 can be supplied from the first inverter 13 to the main breaker 82 via the interconnection breaker 81 and the third connection point p3 in this order. The secondary interconnection breaker 83 can be supplied with the AC power of the voltage V AC2 from the second inverter 44. AC power of voltage V AC1 can be supplied to the power switching unit 28 from the branch breaker 85a. AC power having the voltage V AC1 may be supplied from the branch breaker 85b to the second load 252. AC power of voltage V AC2 can be supplied from the branch breaker 85c to the third load 253.
［電力切替ユニット２８］
　電力切替ユニット２８は、複数の入力部と、電力出力部２８ｃと、を有する。複数の入力部は、系統電力入力部２８ａおよび自立電力入力部２８ｂを含む。電力切替ユニット２８は、複数の入力部のいずれを電力出力部２８ｃに接続するかを切り替える。この例では、電力切替ユニット２８は、系統電力入力部２８ａおよび自立電力入力部２８ｂのいずれを電力出力部２８ｃに接続するかを切り替える。この例では、こうして、電力切替ユニット２８は、第１インバータ１３と分岐ブレーカー８５ａとのいずれかを、選択的に、自立分電盤９０に、具体的には主幹ブレーカー９２に、接続する。 [Power switching unit 28]
The power switching unit 28 has a plurality of input parts and a power output part 28c. The plurality of input units include a system power input unit 28a and an independent power input unit 28b. The power switching unit 28 switches which of the plurality of input units is connected to the power output unit 28c. In this example, the power switching unit 28 switches which of the system power input unit 28a and the self-sustained power input unit 28b is connected to the power output unit 28c. In this example, the power switching unit 28 thus selectively connects one of the first inverter 13 and the branch breaker 85a to the self-sustained distribution board 90, specifically to the main breaker 92.
［自立分電盤９０］
　自立分電盤９０は、主幹ブレーカー９２と、第２分岐部９５を有する。第２分岐部９５は、複数の分岐ブレーカーを含む。この例では、第２分岐部９５は、分岐ブレーカー９５ａ，９５ｂおよび９５ｃを含む。 [Independent distribution board 90]
The self-sustained distribution board 90 has a main breaker 92 and a second branching portion 95. The second branch section 95 includes a plurality of branch breakers. In this example, the second branch portion 95 includes branch breakers 95a, 95b and 95c.
　主幹ブレーカー９２は、上流側電路９８により、電力切替ユニット２８と接続されている。上流側電路９８は、主幹ブレーカー９２を介して下流側電路９９に接続されている。 The main breaker 92 is connected to the power switching unit 28 by an upstream electric circuit 98. The upstream electric circuit 98 is connected to the downstream electric circuit 99 via the main breaker 92.
　下流側電路９９には、第２分岐部９５が接続されている。第２分岐部９５の分岐ブレーカー９５ａは、主幹ブレーカー９２とＤ１電源５５とを接続する経路上に設けられている。分岐ブレーカー９５ｂは、主幹ブレーカー９２と貯湯ユニット４７とを接続する経路上に設けられている。分岐ブレーカー９５ｃは、主幹ブレーカー９２と第１負荷２５１とを接続する経路上に設けられている。 The second branch 95 is connected to the downstream electric circuit 99. The branch breaker 95a of the second branch section 95 is provided on the path connecting the main breaker 92 and the D1 power source 55. The branch breaker 95b is provided on the path connecting the main breaker 92 and the hot water storage unit 47. The branch breaker 95c is provided on the path connecting the main breaker 92 and the first load 251.
　この例では、電力切替ユニット２８から主幹ブレーカー９２を介して下流側電路９９に電圧ＶAC1の交流電力が供給され得る。分岐ブレーカー９５ａからＤ１電源５５に電圧ＶAC1の交流電力が供給され得る。分岐ブレーカー９５ｂから貯湯ユニット４７に電圧ＶAC1の交流電力が供給され得る。分岐ブレーカー９５ｃからコンセント２６０を介して第１負荷２５１に電圧ＶAC1の交流電力が供給され得る。 In this example, the AC power of the voltage V AC1 can be supplied from the power switching unit 28 to the downstream electric circuit 99 via the main breaker 92. AC power having a voltage V AC1 can be supplied from the branch breaker 95a to the D1 power supply 55. AC power having a voltage V AC1 can be supplied from the branch breaker 95b to the hot water storage unit 47. AC power having the voltage V AC1 may be supplied from the branch breaker 95c to the first load 251 through the outlet 260.
［系統連系時の電力システム３００の動作］
　図１に示すように、系統連系時には、制御器５１からの解列指令に基づき、保護リレー６２が開状態となっている。ここで、開状態は、自身を電流が流れることを禁止する状態を指す。また、電力切替ユニット２８では、系統電力入力部２８ａと電力出力部２８ｃとが接続されている。こうして、電力切替ユニット２８は、分岐ブレーカー８５ａと自立分電盤９０とを接続している。 [Operation of power system 300 during grid interconnection]
As shown in FIG. 1, at the time of system interconnection, the protection relay 62 is open based on the disconnection command from the controller 51. Here, the open state refers to a state in which a current is prohibited from flowing through itself. In the power switching unit 28, the system power input unit 28a and the power output unit 28c are connected. In this way, the power switching unit 28 connects the branch breaker 85a and the self-sustained distribution board 90.
　燃料電池４１で発電された電力は、第５ＤＣＤＣコンバータ４２を経由して第２ＤＣバス４３に供給される。第２ＤＣバス４３に供給された電力の一部または全部は、第２インバータ４４を経由して二次連系ブレーカー８３に供給される。 Electric power generated by the fuel cell 41 is supplied to the second DC bus 43 via the fifth DCDC converter 42. Part or all of the electric power supplied to the second DC bus 43 is supplied to the secondary interconnection breaker 83 via the second inverter 44.
　二次連系ブレーカー８３に供給された電力の一部は、分岐ブレーカー８５ａと電力切替ユニット２８とをこの順に経由して、主幹ブレーカー９２に供給される。主幹ブレーカー９２に供給された電力の一部は、分岐ブレーカー９５ａを経由して、Ｄ１電源５５に供給される。主幹ブレーカー９２に供給された電力の別の一部は、分岐ブレーカー９５ｂを経由して、貯湯ユニット４７に供給される。主幹ブレーカー９２に供給された電力のさらに別の一部は、分岐ブレーカー９５ｃとコンセント２６０とをこの順に経由して、第１負荷２５１に供給される。 A part of the electric power supplied to the secondary interconnection breaker 83 is supplied to the main breaker 92 via the branch breaker 85a and the electric power switching unit 28 in this order. A part of the electric power supplied to the main breaker 92 is supplied to the D1 power supply 55 via the branch breaker 95a. Another part of the electric power supplied to the main breaker 92 is supplied to the hot water storage unit 47 via the branch breaker 95b. Another part of the electric power supplied to the main breaker 92 is supplied to the first load 251 via the branch breaker 95c and the outlet 260 in this order.
　二次連系ブレーカー８３に供給された電力の別の一部は、分岐ブレーカー８５ｂを経由して、第２負荷２５２に供給される。二次連系ブレーカー８３に供給された電力のさらに別の一部は、分岐ブレーカー８５ｃを経由して、第３負荷２５３に供給される。 Another part of the electric power supplied to the secondary interconnection breaker 83 is supplied to the second load 252 via the branch breaker 85b. Another part of the electric power supplied to the secondary interconnection breaker 83 is supplied to the third load 253 via the branch breaker 85c.
　余剰電力に所定マージンを加えた電力がゼロよりも大きい場合、その電力は、第２ＤＣバス４３から第６ＤＣＤＣコンバータ４５を経由してヒーター４６に供給される。 When the power obtained by adding a predetermined margin to the surplus power is larger than zero, the power is supplied from the second DC bus 43 to the heater 46 via the sixth DCDC converter 45.
　直流電力変換装置２０は、具体的には第２ＤＣＤＣコンバータ２２は、ＭＰＰＴ制御により、第１太陽光発電システム３１から電力を取り出し、取り出した電力を第１ＤＣバス１１に供給する。直流電力変換装置２０は、具体的には第３ＤＣＤＣコンバータ２３は、ＭＰＰＴ制御により、第２太陽光発電システム３２から電力を取り出し、取り出した電力を第１ＤＣバス１１に供給する。 The DC power converter 20, specifically, the second DCDC converter 22 extracts power from the first photovoltaic power generation system 31 by MPPT control, and supplies the extracted power to the first DC bus 11. The DC power conversion device 20, specifically, the third DCDC converter 23 extracts power from the second solar power generation system 32 by MPPT control, and supplies the extracted power to the first DC bus 11.
　蓄電装置２５が満充電状態にない場合、第１ＤＣバス１１に供給された電力の一部が蓄電装置２５に供給され、該電力の残部が第１インバータ１３に供給される。蓄電装置２５が満充電状態にある場合、第１ＤＣバス１１に供給された電力の全部が第１インバータ１３に供給される。第１インバータ１３に供給された電力は、連系ブレーカー８１に供給される。 When the power storage device 25 is not in a fully charged state, a part of the electric power supplied to the first DC bus 11 is supplied to the power storage device 25, and the rest of the power is supplied to the first inverter 13. When the power storage device 25 is fully charged, all the electric power supplied to the first DC bus 11 is supplied to the first inverter 13. The power supplied to the first inverter 13 is supplied to the interconnection breaker 81.
　上記の説明から理解されるように、この例の電力システム３００は、第２インバータ４４から二次連系ブレーカー８３へと供給される電力が、少なくとも上記マージンの分だけ、負荷２５１～２５３、Ｄ１電源５５および貯湯ユニット４７の合計要求負荷に対して不足するように構成されている。この不足分に相当する電力が、連系ブレーカー８１から主幹ブレーカー８２を経由して下流側電路８９へと供給され、第２インバータ４４から二次連系ブレーカー８３へと供給された電力とともに、第１分岐部８５に供給される。連系ブレーカー８１に供給された電力の残部は、系統電源２００に逆潮流される。 As can be understood from the above description, in the power system 300 of this example, the power supplied from the second inverter 44 to the secondary interconnection breaker 83 is at least the amount of the above-mentioned margin, and the loads 251 to 253 and D1. The power supply 55 and the hot water storage unit 47 are configured to be insufficient with respect to the total required load. Electric power corresponding to this shortage is supplied from the interconnection breaker 81 to the downstream electric circuit 89 via the main breaker 82, and together with the electric power supplied from the second inverter 44 to the secondary interconnection breaker 83, It is supplied to the one-branching unit 85. The balance of the electric power supplied to the interconnection breaker 81 flows backward to the system power supply 200.
　太陽光発電システム３１および３２での発電が不十分な場合、上記の不足分の電力が、系統電源２００から主幹ブレーカー８２を経由して下流側電路８９へと供給され、第２インバータ４４から二次連系ブレーカー８３へと供給された電力とともに、第１分岐部８５に供給される。また、蓄電装置２５が満充電状態でなくかつ太陽光発電システム３１および３２での発電が蓄電装置２５を充電するのに不十分な場合、系統電源２００から、第１インバータ１３、第１ＤＣバス１１および第４ＤＣＤＣコンバータ１２を経由して、蓄電装置２５に電力が供給される。 When the power generation by the solar power generation systems 31 and 32 is insufficient, the above-mentioned shortage of power is supplied from the system power supply 200 to the downstream side electric line 89 via the main breaker 82, and the second inverter 44 supplies two power. It is supplied to the first branch section 85 together with the electric power supplied to the next interconnection breaker 83. If the power storage device 25 is not fully charged and the power generation by the photovoltaic power generation systems 31 and 32 is insufficient to charge the power storage device 25, the system power supply 200, the first inverter 13, the first DC bus 11 Electric power is supplied to the power storage device 25 via the fourth DCDC converter 12.
［停電時の電力システム３００の動作］
　図２に示すように、停電時には、制御器５１からの並列指令に基づき、保護リレー６２が閉状態となっている。ここで、閉状態は、自身を電流が流れることを許可する状態を指す。また、電力切替ユニット２８は、第１インバータ１３と自立分電盤９０とを接続している。 [Operation of power system 300 during power failure]
As shown in FIG. 2, at the time of a power failure, the protection relay 62 is in the closed state based on the parallel command from the controller 51. Here, the closed state refers to a state in which a current is allowed to flow through itself. Further, the power switching unit 28 connects the first inverter 13 and the self-sustained distribution board 90.
　燃料電池４１で発電された電力は、ＤＣＤＣコンバータ４２を経由して第２ＤＣバス４３に供給される。第２ＤＣバス４３に供給された直流電力の一部または全部は、特性変換回路１００に供給される。直流電力変換装置２０は、具体的には第１ＤＣＤＣコンバータ２１は、ＭＰＰＴ制御により特性変換回路１００から（厳密にはＬＣフィルタ６１を介して）電力を取り出し、取り出した電力を第１ＤＣバス１１に供給する。 Electric power generated by the fuel cell 41 is supplied to the second DC bus 43 via the DCDC converter 42. Part or all of the DC power supplied to the second DC bus 43 is supplied to the characteristic conversion circuit 100. In the DC power converter 20, specifically, the first DCDC converter 21 extracts power from the characteristic conversion circuit 100 (strictly, via the LC filter 61) by MPPT control, and supplies the extracted power to the first DC bus 11. To do.
　また、直流電力変換装置２０は、系統連系時と同様に、太陽光発電システム３１および３２から電力を取り出し、取り出した電力を第１ＤＣバス１１に供給する。 Further, the DC power conversion device 20 takes out electric power from the solar power generation systems 31 and 32 and supplies the taken out electric power to the first DC bus 11 as in the grid interconnection.
　直流電力変換装置２０によって太陽光発電システム３１および３２ならびに特性変換回路１００から取り出された合計電力が第１負荷２５１、Ｄ１電源５５および貯湯ユニット４７の要求負荷よりも小さい場合、不足分に相当する電力が、蓄電装置２５から第４ＤＣＤＣコンバータ１２を経由して第１ＤＣバス１１にさらに供給される。取り出された電力が要求負荷よりも大きい場合、過剰分の電力が第４ＤＣＤＣコンバータ１２を介して蓄電装置２５に充電され、この充電を行っても過剰分の電力が余る場合は、第２ＤＣバス４３の電力の一部が第６ＤＣＤＣコンバータ４５を介してヒーター４６に供給される。 When the total power extracted from the photovoltaic power generation systems 31 and 32 and the characteristic conversion circuit 100 by the DC power converter 20 is smaller than the required load of the first load 251, the D1 power source 55, and the hot water storage unit 47, it corresponds to the shortfall. Electric power is further supplied from power storage device 25 to first DC bus 11 via fourth DCDC converter 12. When the extracted power is larger than the required load, the excess power is charged in the power storage device 25 via the fourth DCDC converter 12, and when the excess power is left after this charging, the second DC bus 43 is used. A part of the electric power of is supplied to the heater 46 via the sixth DCDC converter 45.
　このようにして、上記要求負荷に追従させられたあるいは近づけられた電力が、第１ＤＣバス１１から第１インバータ１３および電力切替ユニット２８を経由して主幹ブレーカー９２に供給される。主幹ブレーカー９２に供給された電力は、系統連系時と同様に、Ｄ１電源５５、貯湯ユニット４７および第１負荷２５１に供給される。 In this way, the electric power which is made to follow the required load or brought close thereto is supplied from the first DC bus 11 to the main breaker 92 via the first inverter 13 and the electric power switching unit 28. The electric power supplied to the main breaker 92 is supplied to the D1 power source 55, the hot water storage unit 47, and the first load 251 as in the system interconnection.
［電力システム３００における機器の接続の仕方による利点］
　この例では、電力システム３００は、蓄電装置２５を備える。太陽光発電システム３１および３２と、直流電力変換装置２０と、蓄電装置２５と、はこの順に接続されている。また、燃料電池発電システム４０と、特性変換回路１００と、直流電力変換装置２０と、蓄電装置２５と、はこの順に接続されている。このため、太陽光発電システム３１および３２からのみならず、燃料電池発電システム４０からも、蓄電装置２５を充電することができる。 [Advantages of how to connect devices in power system 300]
In this example, power system 300 includes power storage device 25. The solar power generation systems 31 and 32, the DC power conversion device 20, and the power storage device 25 are connected in this order. Further, the fuel cell power generation system 40, the characteristic conversion circuit 100, the DC power conversion device 20, and the power storage device 25 are connected in this order. Therefore, the power storage device 25 can be charged not only from the solar power generation systems 31 and 32 but also from the fuel cell power generation system 40.
　この例では、電力システム３００は、蓄電装置２５と、直流電力を交流電力に変換するインバータ１３と、コンセント２６０と、を備える。太陽光発電システム３１および３２と、直流電力変換装置２０と、インバータ１３と、コンセント２６０と、はこの順に接続されている。燃料電池発電システム４０と、特性変換回路１００と、直流電力変換装置２０と、インバータ１３と、コンセント２６０と、はこの順に接続されている。蓄電装置２５と、インバータ１３と、コンセント２６０と、はこの順に接続されている。このため、この例では、太陽光発電システム３１および３２ならびに蓄電装置２５から電力供給されるコンセント２６０に、燃料電池発電システム４０からも電力供給できる。このことは、以下の理由で、停電時に便利である。すなわち、夜、雨天時などには、太陽光発電システム３１および３２は発電できない。仮にコンセント２６０に燃料電池発電システム４０から電力を供給できないとすると、夜、雨天時などに停電が続く場合において、コンセント２６０から電力を取り出し可能な期間は蓄電装置２５のみに基づく限られたものとなる。これに対し、この例では、コンセント２６０に燃料電池発電システム４０から電力を供給できるため、上記期間を延ばすことができる。夜、雨天時などに停電が続く場合において、別のコンセントへの差し替えなしで１つのコンセントから長時間電力を取り出せることは、ユーザーにとって便利である。 In this example, the power system 300 includes a power storage device 25, an inverter 13 that converts DC power into AC power, and an outlet 260. The photovoltaic power generation systems 31 and 32, the DC power converter 20, the inverter 13, and the outlet 260 are connected in this order. The fuel cell power generation system 40, the characteristic conversion circuit 100, the DC power conversion device 20, the inverter 13, and the outlet 260 are connected in this order. Power storage device 25, inverter 13, and outlet 260 are connected in this order. Therefore, in this example, power can be supplied from the fuel cell power generation system 40 to the outlet 260 supplied with power from the solar power generation systems 31 and 32 and the power storage device 25. This is convenient during a power failure for the following reasons. That is, the solar power generation systems 31 and 32 cannot generate power at night or in rainy weather. If power cannot be supplied from the fuel cell power generation system 40 to the outlet 260, the period during which power can be taken out of the outlet 260 is limited based on only the power storage device 25 when power failure continues, such as at night or in rainy weather. Become. On the other hand, in this example, since the electric power can be supplied from the fuel cell power generation system 40 to the outlet 260, the above period can be extended. It is convenient for the user to be able to take out the electric power from one outlet for a long time without being replaced with another outlet when the power failure continues at night or in the rain.
　また、この例では、コンセント２６０に対する上記接続と同様の接続が、貯湯ユニット４７にもなされている。このため、夜、雨天時などに停電が続く場合において、貯湯ユニット４７へとその動作に必要な電力を長時間供給することができる。 In this example, the hot water storage unit 47 is also connected to the outlet 260 in the same manner as the above. Therefore, in the event of a power outage that continues at night or in the case of rain, the hot water storage unit 47 can be supplied with the power required for its operation for a long time.
　この例では、電力システム３００は、蓄電装置２５から燃料電池発電システム４０に（具体的には、Ｄ１電源５５に）電力を供給することができるように構成されている。具体的には、コンセント２６０に対する上記接続と同様の接続が、Ｄ１電源５５にもなされている。このようにすれば、停電時に燃料電池発電システム４０を起動させるための専用電源を省略することができる。専用電源は、典型的には、燃料電池発電システム４０の補機に電力を供給するための電源である。 In this example, the power system 300 is configured to be able to supply power from the power storage device 25 to the fuel cell power generation system 40 (specifically, to the D1 power supply 55). Specifically, the same connection as the above connection to the outlet 260 is also made to the D1 power supply 55. In this way, the dedicated power supply for starting the fuel cell power generation system 40 at the time of power failure can be omitted. The dedicated power source is typically a power source for supplying power to the auxiliary equipment of the fuel cell power generation system 40.
［特性変換回路の具体例］
　以下、特性変換回路１００の具体例である特性変換回路１００Ｘについて、図８を参照しながら説明する。以下では、図４を参照して既に説明した要素については、同一符号を付し、その説明を省略することがある。 [Specific example of characteristic conversion circuit]
Hereinafter, a characteristic conversion circuit 100X, which is a specific example of the characteristic conversion circuit 100, will be described with reference to FIG. In the following, the elements already described with reference to FIG. 4 are denoted by the same reference numerals, and the description thereof may be omitted.
　特性変換回路１００Ｘでは、ＬＬＣコンバータが構成されている。このＬＬＣコンバータは、電流供給電源１３１から流出する電流が大きいほど高い発振周波数が規定され、発振周波数が高いほど特性変換回路１００Ｘの入力電圧に対する出力電圧の比率が小さくなるように構成されている。 A LLC converter is configured in the characteristic conversion circuit 100X. The LLC converter is configured such that the higher the current flowing from the current supply power source 131, the higher the oscillation frequency is defined, and the higher the oscillation frequency, the smaller the ratio of the output voltage to the input voltage of the characteristic conversion circuit 100X.
　具体的には、特性変換回路１００Ｘでは、第１フィードバック回路１１０と、第２フィードバック回路１２０と、フィードバック電流供給部１３０Ｘと、電流共振制御部１４０と、電圧電流制御回路１６０Ｘと、が設けられている。電圧電流制御回路１６０Ｘが、上記ＬＬＣコンバータを構成している。 Specifically, the characteristic conversion circuit 100X is provided with a first feedback circuit 110, a second feedback circuit 120, a feedback current supply unit 130X, a current resonance control unit 140, and a voltage/current control circuit 160X. There is. The voltage/current control circuit 160X constitutes the LLC converter.
　フィードバック電流供給部１３０Ｘは、電流供給電源１３１および第７抵抗１３２に加え、第１発光ダイオード１３５を有する。第１発光ダイオード１３５には、電流供給電源１３１から流出した電流が流れる。 The feedback current supply unit 130X has a first light emitting diode 135 in addition to the current supply power source 131 and the seventh resistor 132. The current flowing from the current supply power source 131 flows through the first light emitting diode 135.
　電流共振制御部１４０は、第８抵抗１４１と、第１コンデンサ１４２と、第９抵抗１４３と、第１フォトトランジスタ１４５と、制御ＩＣ１４６と、を有する。第８抵抗１４１と、第１コンデンサ１４２と、第９抵抗１４３および第１フォトトランジスタ１４５の組み合わせとは、互いに並列に接続されている。第１フォトトランジスタ１４５は、第１発光ダイオード１３５と協働して、第１フォトカプラ１５０を構成している。制御ＩＣ１４６は、定電流源１４７と、フィードバック端子１４８と、ハイサイドドライバ出力端子１４９ａと、ローサイドドライバ出力端子１４９ｂと、を有する。 The current resonance control unit 140 has an eighth resistor 141, a first capacitor 142, a ninth resistor 143, a first phototransistor 145, and a control IC 146. The eighth resistor 141, the first capacitor 142, and the combination of the ninth resistor 143 and the first phototransistor 145 are connected in parallel with each other. The first phototransistor 145 cooperates with the first light emitting diode 135 to form the first photocoupler 150. The control IC 146 includes a constant current source 147, a feedback terminal 148, a high side driver output terminal 149a, and a low side driver output terminal 149b.
　電流共振制御部１４０では、第１コンデンサ１４２に電荷が充電される期間（以下、充電期間と称することがある）と、第１コンデンサ１４２から電荷が放電される期間（以下、放電期間と称することがある）とが、交互に訪れる。放電期間と充電期間とは、フィードバック端子１４８の電圧に基づいて切り替わる。 In the current resonance control unit 140, a period during which the first capacitor 142 is charged with electric charge (hereinafter, may be referred to as a charging period) and a period during which electric charge is discharged from the first capacitor 142 (hereinafter, referred to as a discharging period). There are) and alternate. The discharging period and the charging period are switched based on the voltage of the feedback terminal 148.
　具体的には、充電期間において、定電流源１４７からフィードバック端子１４８を介して第１コンデンサ１４２に電荷が充電されていく。充電が進むにつれて、フィードバック端子１４８の電圧が上昇していく。フィードバック端子１４８の電圧が第１の電圧に達すると、放電期間に切り替わる。放電期間においては、定電流源１４７から第１コンデンサ１４２への電荷の充電は停止される。放電期間においては、第１コンデンサ１４２に充電された電荷は、第８抵抗１４１を介して放電される。放電期間においては、電荷が第９抵抗１４３および第１フォトトランジスタ１４５を介してさらに放電される。放電が進むにつれて、フィードバック端子１４８の電圧が低下していく。フィードバック端子１４８の電圧が第２の電圧に達すると、充電期間に切り替わる。 Specifically, during the charging period, the constant current source 147 charges the first capacitor 142 via the feedback terminal 148. As the charging progresses, the voltage of the feedback terminal 148 rises. When the voltage at the feedback terminal 148 reaches the first voltage, the discharge period is switched. During the discharging period, charging of the electric charge from the constant current source 147 to the first capacitor 142 is stopped. During the discharging period, the electric charge charged in the first capacitor 142 is discharged through the eighth resistor 141. In the discharging period, the electric charge is further discharged through the ninth resistor 143 and the first phototransistor 145. As the discharge progresses, the voltage of the feedback terminal 148 decreases. When the voltage of the feedback terminal 148 reaches the second voltage, the charging period is switched.
　第１発光ダイオード１３５を流れる電流が大きいほど、第１フォトトランジスタ１４５に大きい電流が流れ、放電期間における第９抵抗１４３および第１フォトトランジスタ１４５を介した電荷の放電が速くなり、放電期間が短くなり、充放電周波数が高くなる。充放電周波数は、上記の発振周波数に対応する。 The larger the current flowing through the first light emitting diode 135, the larger the current flows through the first phototransistor 145, the faster the discharge of the charge through the ninth resistor 143 and the first phototransistor 145 during the discharge period, and the shorter the discharge period. And the charging/discharging frequency becomes high. The charge/discharge frequency corresponds to the above oscillation frequency.
　ある放電期間において、ハイサイドドライバ出力端子１４９ａから駆動信号が出力される。次の放電期間において、ローサイドドライバ出力端子１４９ｂから駆動信号が出力される。次の放電期間において、ハイサイドドライバ出力端子１４９ａから駆動信号が出力される。次の放電期間において、ローサイドドライバ出力端子１４９ｂから駆動信号が出力される。これが繰り返され、ドライバ出力端子１４９ａおよび１４９ｂから、互いに逆位相の駆動パルス信号が出力される。これらの駆動パルス信号の周波数は、上記の充放電周波数が高くなるほど高くなる。なお、充電期間は、両ドライバ出力端子１４９ａおよび１４９ｂのいずれからも駆動信号が出力されないデッドタイムとなる。 During a certain discharge period, a drive signal is output from the high side driver output terminal 149a. In the next discharge period, a drive signal is output from the low side driver output terminal 149b. In the next discharge period, a drive signal is output from the high side driver output terminal 149a. In the next discharge period, a drive signal is output from the low side driver output terminal 149b. This is repeated, and drive pulse signals having mutually opposite phases are output from the driver output terminals 149a and 149b. The frequencies of these drive pulse signals become higher as the charging/discharging frequency becomes higher. The charging period is a dead time during which no drive signal is output from both driver output terminals 149a and 149b.
　電圧電流制御回路１６０Ｘは、第２コンデンサ１６１と、第１スイッチング素子１６２ａと、第２スイッチング素子１６２ｂと、第３コンデンサ１６３ａと、第４コンデンサ１６３ｂと、第５コンデンサ１６４と、トランス１６５と、第１ダイオード１６６ａと、第２ダイオード１６６ｂと、第６コンデンサ１６７と、を有する。 The voltage/current control circuit 160X includes a second capacitor 161, a first switching element 162a, a second switching element 162b, a third capacitor 163a, a fourth capacitor 163b, a fifth capacitor 164, a transformer 165, and It has one diode 166a, a second diode 166b, and a sixth capacitor 167.
　スイッチング素子１６２ａおよび１６２ｂは、直列に接続されることにより、直列回路を構成している。この直列回路には、第２コンデンサ１６１が並列接続されている。第１スイッチング素子１６２ａには第３コンデンサ１６３ａが並列接続されている。第２スイッチング素子１６２ｂには第４コンデンサ１６３ｂが並列接続されている。 The switching elements 162a and 162b are connected in series to form a series circuit. The second capacitor 161 is connected in parallel to this series circuit. The third capacitor 163a is connected in parallel to the first switching element 162a. The fourth capacitor 163b is connected in parallel to the second switching element 162b.
　この例では、スイッチング素子１６２ａおよび１６２ｂは、ＭＯＳＦＥＴ（Metal-Oxide-Semiconductor Field-Effect Transistor）である。また、第５コンデンサ１６４は、共振コンデンサである。 In this example, the switching elements 162a and 162b are MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). The fifth capacitor 164 is a resonance capacitor.
　トランス１６５は、１次側の巻線である第１巻線１６５ａと、２次側の巻線である第２巻線１６５ｂおよび第３巻線１６５ｃと、を有する。 The transformer 165 has a first winding 165a which is a primary winding, and a second winding 165b and a third winding 165c which are secondary windings.
　第１巻線１６５ａの一端には、第１スイッチング素子１６２ａの電流流出端子と、第２スイッチング素子１６２ｂの電流流入端子と、が接続されている。第１巻線１６５ａの他端と第２スイッチング素子１６２ｂの電流流出端子との間には、第５コンデンサ１６４が接続されている。なお、この例では、電流流出端子はソース端子である。電流流入端子は、ドレイン端子である。 A current outflow terminal of the first switching element 162a and a current inflow terminal of the second switching element 162b are connected to one end of the first winding 165a. The fifth capacitor 164 is connected between the other end of the first winding 165a and the current outflow terminal of the second switching element 162b. In this example, the current outflow terminal is the source terminal. The current inflow terminal is the drain terminal.
　第２巻線１６５ｂの一端には、第１ダイオード１６６ａのアノードが接続されている。第１ダイオード１６６ａのカソードには、第６コンデンサ１６７の一端と、第２ダイオード１６６ｂのカソードと、が接続されている。第２巻線１６５ｂの他端には、第６コンデンサ１６７の他端と、基準電位とが接続されている。 The anode of the first diode 166a is connected to one end of the second winding 165b. One end of the sixth capacitor 167 and the cathode of the second diode 166b are connected to the cathode of the first diode 166a. The other end of the sixth capacitor 167 and the reference potential are connected to the other end of the second winding 165b.
　第３巻線１６５ｃの一端には、第６コンデンサ１６７の他端と、基準電位とが接続されている。第３巻線１６５ｃの他端には、第２ダイオード１６６ｂのアノードが接続されている。 The other end of the sixth capacitor 167 and the reference potential are connected to one end of the third winding 165c. The anode of the second diode 166b is connected to the other end of the third winding 165c.
　第１スイッチング素子１６２ａの制御端子には、ハイサイドドライバ出力端子１４９ａから駆動パルス信号が供給される。第２スイッチング素子１６２ｂの制御端子には、ローサイドドライバ出力端子１４９ｂから駆動パルス信号が供給される。これにより、スイッチング素子１６２ａおよび１６２ｂは、互いに逆位相の駆動パルス信号が供給されることによって、交互にオンオフする。なお、この例では、制御端子は、ゲート端子である。 A drive pulse signal is supplied to the control terminal of the first switching element 162a from the high side driver output terminal 149a. A drive pulse signal is supplied to the control terminal of the second switching element 162b from the low side driver output terminal 149b. As a result, the switching elements 162a and 162b are alternately turned on/off by being supplied with drive pulse signals having opposite phases. In addition, in this example, the control terminal is a gate terminal.
　スイッチング素子１６２ａおよび１６２ｂに供給される駆動パルス信号の周波数が高いほど、ＬＬＣ共振に基づき、電圧電流制御回路１６０Ｘの入力電圧に対する出力電圧の比率が小さくなる。 The higher the frequency of the drive pulse signal supplied to the switching elements 162a and 162b, the smaller the ratio of the output voltage to the input voltage of the voltage/current control circuit 160X based on LLC resonance.
［特性変換回路の別例］
　図９に、特性変換回路の別例を示す。以下では、図４の例と同様の部分については、同一符号を付し、その説明を省略することがある。 [Another example of characteristic conversion circuit]
FIG. 9 shows another example of the characteristic conversion circuit. In the following, the same parts as those in the example of FIG. 4 are denoted by the same reference numerals, and description thereof may be omitted.
　図９に示す特性変換回路１９０では、図４の特性変換回路１００のフィードバック電流供給部１３０に代えて、フィードバック電流供給部１９５が設けられている。フィードバック電流供給部１９５は、電流供給電源１３１および第７抵抗１３２に加え、第１０抵抗１９１を有する。 In the characteristic conversion circuit 190 shown in FIG. 9, a feedback current supply section 195 is provided instead of the feedback current supply section 130 of the characteristic conversion circuit 100 in FIG. The feedback current supply unit 195 has a tenth resistor 191 in addition to the current supply power source 131 and the seventh resistor 132.
　特性変換回路１９０では、特性変換回路１００と同様、第１シャントレギュレータ１１５の第１参照電圧端子に入力される電圧が大きいほど、電流供給電源１３１、第７抵抗１３２、第１シャントレギュレータ１１５および基準電位をこの順に流れる電流すなわち第１電流が大きくなる。一方、特性変換回路１９０では、特性変換回路１００と異なり、第２シャントレギュレータ１２５の第２参照電圧端子に入力される電圧が大きいほど、電流供給電源１３１、第１０抵抗１９１、第２シャントレギュレータ１２５および基準電位をこの順に流れる電流すなわち第２電流が大きくなる。 In the characteristic conversion circuit 190, like the characteristic conversion circuit 100, the larger the voltage input to the first reference voltage terminal of the first shunt regulator 115, the more the current supply power supply 131, the seventh resistor 132, the first shunt regulator 115, and the reference. The current flowing through the potential in this order, that is, the first current increases. On the other hand, in the characteristic conversion circuit 190, unlike the characteristic conversion circuit 100, the larger the voltage input to the second reference voltage terminal of the second shunt regulator 125, the more the current supply power supply 131, the tenth resistor 191, and the second shunt regulator 125. The current flowing through the reference potential in this order, that is, the second current increases.
　特性変換回路１９０の出力電流が小さい領域では、第２電流ｉ２は実質的にゼロとなり、電流供給電源１３１から流出する電流は、実質的に第１電流ｉ１である。一方、特性変換回路１００の出力電流が大きい領域では、第１電流ｉ１は実質的にゼロとなり、電流供給電源１３１から流出する電流は、実質的に第２電流ｉ２である。つまり、特性変換回路１９０の出力電流が小さい領域では第１フィードバック回路１１０によって、特性変換回路１９０の出力電流が大きい領域では第２フィードバック回路１２０によって、特性変換回路１９０における特性変換が行われると言える。これらの点で、特性変換回路１９０は、特性変換回路１００と共通している。このため、特性変換回路１９０では、特性変換回路１００と同様に、電圧電流制御回路１６０の入力電圧に対する出力電圧の比率が調整される。 In a region where the output current of the characteristic conversion circuit 190 is small, the second current i2 becomes substantially zero, and the current flowing out from the current supply power source 131 is substantially the first current i1. On the other hand, in a region where the output current of the characteristic conversion circuit 100 is large, the first current i1 becomes substantially zero, and the current flowing out from the current supply power source 131 is substantially the second current i2. That is, it can be said that the first feedback circuit 110 performs the characteristic conversion in the region where the output current of the characteristic conversion circuit 190 is small, and the second feedback circuit 120 performs the characteristic conversion in the region where the output current of the characteristic conversion circuit 190 is large. .. In these respects, the characteristic conversion circuit 190 is common to the characteristic conversion circuit 100. Therefore, in the characteristic conversion circuit 190, as in the characteristic conversion circuit 100, the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 is adjusted.
　図１０に、特性変換回路１９０の具体例である特性変換回路１９０Ｘを示す。以下では、図８の例と同様の部分については、同一符号を付し、説明を省略することがある。 FIG. 10 shows a characteristic conversion circuit 190X which is a specific example of the characteristic conversion circuit 190. In the following, the same parts as those in the example of FIG. 8 are denoted by the same reference numerals, and description thereof may be omitted.
　図１０に示す特性変換回路１９０Ｘでは、図８の特性変換回路１００Ｘのフィードバック電流供給部１３０Ｘに代えて、フィードバック電流供給部１９５Ｘが設けられている。また、特性変換回路１９０Ｘでは、特性変換回路１００Ｘの電流共振制御部１４０に代えて、電流共振制御部１９９が設けられている。 In the characteristic conversion circuit 190X shown in FIG. 10, a feedback current supply section 195X is provided instead of the feedback current supply section 130X of the characteristic conversion circuit 100X in FIG. Further, in the characteristic conversion circuit 190X, a current resonance control section 199 is provided instead of the current resonance control section 140 of the characteristic conversion circuit 100X.
　フィードバック電流供給部１９５Ｘは、電流供給電源１３１、第７抵抗１３２および第１発光ダイオード１３５に加え、第１０抵抗１９１および第２発光ダイオード１９２を有する。電流共振制御部１９９は、第８抵抗１４１、第１コンデンサ１４２、第９抵抗１４３、第１フォトトランジスタ１４５および制御ＩＣ１４６に加え、第１１抵抗１９６および第２フォトトランジスタ１９７を有する。 The feedback current supply unit 195X has a tenth resistor 191 and a second light emitting diode 192 in addition to the current supply power source 131, the seventh resistor 132 and the first light emitting diode 135. The current resonance control unit 199 includes an eighth resistor 141, a first capacitor 142, a ninth resistor 143, a first phototransistor 145, and a control IC 146, as well as an eleventh resistor 196 and a second phototransistor 197.
　第８抵抗１４１と、第１コンデンサ１４２と、第９抵抗１４３および第１フォトトランジスタ１４５の組み合わせと、第１１抵抗１９６および第２フォトトランジスタ１９７の組み合わせとは、互いに並列に接続されている。第２発光ダイオード１９２および第２フォトトランジスタ１９７は、協働して、第２フォトカプラ１９８を構成している。 The combination of the eighth resistor 141, the first capacitor 142, the ninth resistor 143 and the first phototransistor 145, and the combination of the eleventh resistor 196 and the second phototransistor 197 are connected in parallel with each other. The second light emitting diode 192 and the second phototransistor 197 cooperate with each other to form a second photocoupler 198.
　電流共振制御部１９９では、電流共振制御部１４０と同様、第１コンデンサ１４２に電荷が充電される期間（以下、充電期間と称することがある）と、第１コンデンサ１４２から電荷が放電される期間（以下、放電期間と称することがある）とが、交互に訪れる。 In the current resonance control unit 199, like the current resonance control unit 140, a period in which the first capacitor 142 is charged (hereinafter, also referred to as a charging period) and a period in which the first capacitor 142 is discharged. (Hereinafter, may be referred to as a discharge period) alternately.
　具体的には、充電期間において、定電流源１４７からフィードバック端子１４８を介して第１コンデンサ１４２に電荷が充電されていく。充電が進むにつれて、フィードバック端子１４８の電圧が上昇していく。フィードバック端子１４８の電圧が第１の電圧に達すると、放電期間に切り替わる。放電期間においては、定電流源１４７から第１コンデンサ１４２への電荷の充電は停止される。放電期間においては、第１コンデンサ１４２に充電された電荷は、第８抵抗１４１を介して放電される。放電期間においては、電荷が、第９抵抗１４３および第１フォトトランジスタ１４５を介して、または、第１１抵抗１９６および第２フォトトランジスタ１９７を介して、さらに放電される。放電が進むにつれて、フィードバック端子１４８の電圧が低下していく。フィードバック端子１４８の電圧が第２の電圧に達すると、充電期間に切り替わる。 Specifically, during the charging period, the constant current source 147 charges the first capacitor 142 via the feedback terminal 148. As the charging progresses, the voltage of the feedback terminal 148 rises. When the voltage at the feedback terminal 148 reaches the first voltage, the discharge period is switched. During the discharging period, charging of the electric charge from the constant current source 147 to the first capacitor 142 is stopped. During the discharging period, the electric charge charged in the first capacitor 142 is discharged through the eighth resistor 141. In the discharging period, the electric charge is further discharged through the ninth resistor 143 and the first phototransistor 145 or the eleventh resistor 196 and the second phototransistor 197. As the discharge progresses, the voltage of the feedback terminal 148 decreases. When the voltage of the feedback terminal 148 reaches the second voltage, the charging period is switched.
　電流共振制御部１９９における第１コンデンサ１４２の電荷の充電状態は、電流共振制御部１４０と同様に変化する。このため、特性変換回路１９０Ｘでは、特性変換回路１００Ｘと同様に、電圧電流制御回路１６０Ｘの入力電圧に対する出力電圧の比率が調整される。 The charge state of the electric charge of the first capacitor 142 in the current resonance control unit 199 changes as in the current resonance control unit 140. Therefore, in the characteristic conversion circuit 190X, as in the characteristic conversion circuit 100X, the ratio of the output voltage to the input voltage of the voltage/current control circuit 160X is adjusted.
　改めて断っておくが、図４の特性変換回路１００の具体例は、図８の特性変換回路１００Ｘには限られない。例えば、電流供給電源１３１から流出する電流が大きいほど小さいデューティ比が規定され、そのデューティ比に基づいて動作するＤＣＤＣコンバータを特性変換回路内に構成することもできる。図９の特性変換回路１９０の具体例についても同様である。 It should be noted that the specific example of the characteristic conversion circuit 100 of FIG. 4 is not limited to the characteristic conversion circuit 100X of FIG. For example, the larger the current flowing out from the current supply power source 131, the smaller the duty ratio is defined, and the DCDC converter that operates based on the duty ratio can be configured in the characteristic conversion circuit. The same applies to a specific example of the characteristic conversion circuit 190 of FIG.
　また、図４および図８の第１フィードバック回路１１０および第２フィードバック回路１２０の構成も必須ではない。 Also, the configurations of the first feedback circuit 110 and the second feedback circuit 120 of FIGS. 4 and 8 are not essential.
（第２の実施形態）
　図１１に示す、第２の実施形態に係る特性変換回路を採用することも可能である。以下、図１１を参照しつつ、第２の実施形態に係る特性変換回路について説明する。以下では、第１の実施形態と同様の部分については、同一符号を付し、説明を省略することがある。 (Second embodiment)
It is also possible to employ the characteristic conversion circuit according to the second embodiment shown in FIG. Hereinafter, the characteristic conversion circuit according to the second embodiment will be described with reference to FIG. In the following, the same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof may be omitted.
　図１１の特性変換回路４００では、第１フィードバック回路４１０は、電流センサ１２８および調整器１７０を有する。第２フィードバック回路４２０は、電流センサ１２８および調整器１７０を有する。電流センサ１２８および調整器１７０は、第１フィードバック回路４１０および第２フィードバック回路４２０によって共有されている。 In the characteristic conversion circuit 400 of FIG. 11, the first feedback circuit 410 has a current sensor 128 and a regulator 170. The second feedback circuit 420 has a current sensor 128 and a regulator 170. The current sensor 128 and the regulator 170 are shared by the first feedback circuit 410 and the second feedback circuit 420.
　第１の実施形態と同様、電流センサ１２８は、特性変換回路４００の出力電流の検出を行う。電流センサ１２８は、その検出の結果を表すセンサ出力を出力する。電流センサ１２８は、特性変換回路４００の出力電流が大きくなるほどセンサ出力を大きく出力する。つまり、センサ出力は、特性変換回路４００の出力電流が大きくなるほど大きくなる。センサ出力は、具体的には、センサ電圧Ｖsである。電流センサ１２８は、センサ電圧Ｖsを出力するセンサ出力部１２８ａを含む。本実施形態では、電流センサ１２８が出力するセンサ電圧Ｖsを、第１センサ電圧Ｖsと称することがある。 Similar to the first embodiment, the current sensor 128 detects the output current of the characteristic conversion circuit 400. The current sensor 128 outputs a sensor output indicating the result of the detection. The current sensor 128 outputs a larger sensor output as the output current of the characteristic conversion circuit 400 increases. That is, the sensor output increases as the output current of the characteristic conversion circuit 400 increases. The sensor output is specifically the sensor voltage V s . The current sensor 128 includes a sensor output unit 128a that outputs the sensor voltage V s . In the present embodiment, the sensor voltage V s output by the current sensor 128 may be referred to as the first sensor voltage V s .
　調整器１７０は、可変パラメータを調整できるように構成されている。可変パラメータは、手動で調整可能なものであってもよく、自動的に調整可能なものであってもよい。調整器１７０は、調整器１７０に入力された第１センサ電圧Ｖsを、第２センサ電圧ＶMへと調整する。 The adjuster 170 is configured to adjust a variable parameter. The variable parameter may be manually adjustable or automatically adjustable. The regulator 170 regulates the first sensor voltage V s input to the regulator 170 to the second sensor voltage V M.
　本実施形態では、調整器１７０は第１センサ電圧Ｖsを変圧するＤＣＤＣコンバータである。可変パラメータは、ＤＣＤＣコンバータの変圧比を変更するパラメータである。 In the present embodiment, the regulator 170 is a DCDC converter that transforms the first sensor voltage V s . The variable parameter is a parameter that changes the transformation ratio of the DCDC converter.
　具体的には、本実施形態では、調整器１７０は、図１２に示す構成を有する。図１２の調整器１７０は、分圧回路１７０ａと、増幅回路１７０ｂと、を含む。可変パラメータは、分圧回路１７０ａまたは増幅回路１７０ｂが有するパラメータである。センサ出力部１２８ａと、分圧回路１７０ａと、増幅回路１７０ｂと、接続点ｐｓとは、この順に接続されている。 Specifically, in this embodiment, the adjuster 170 has the configuration shown in FIG. The regulator 170 in FIG. 12 includes a voltage dividing circuit 170a and an amplifier circuit 170b. The variable parameter is a parameter included in the voltage dividing circuit 170a or the amplifier circuit 170b. The sensor output unit 128a, the voltage dividing circuit 170a, the amplifier circuit 170b, and the connection point ps are connected in this order.
　図１２の例では、分圧回路１７０ａは、抵抗ＦＲ１と、抵抗ＦＲ２と、可変抵抗ＶＲ１と、を含む。センサ出力部１２８ａと、抵抗ＦＲ１と、抵抗ＦＲ２と、可変抵抗ＶＲ１と、基準電位とが、この順に接続されている。分圧回路１７０ａは、抵抗ＦＲ１、ＦＲ２およびＶＲ１を用いて、第１センサ電圧Ｖsを分圧する。この分圧により、以下の数式２に示す分圧電圧ＶDが生成される。ここで、ＦＲ１は、抵抗ＦＲ１の抵抗値である。ＦＲ１は、抵抗ＦＲ２の抵抗値である。ＶＲ１は、可変抵抗ＶＲ１の抵抗値である。「＊」は、乗算を表す記号である。
　数式２：ＶD＝Ｖs＊（ＦＲ２＋ＶＲ１）／（ＦＲ１＋ＦＲ２＋ＶＲ１） In the example of FIG. 12, the voltage dividing circuit 170a includes a resistor FR1, a resistor FR2, and a variable resistor VR1. The sensor output unit 128a, the resistor FR1, the resistor FR2, the variable resistor VR1 and the reference potential are connected in this order. The voltage dividing circuit 170a divides the first sensor voltage V s by using the resistors FR1, FR2 and VR1. By this voltage division, the divided voltage V D shown in the following Equation 2 is generated. Here, FR1 is the resistance value of the resistor FR1. FR1 is the resistance value of the resistor FR2. VR1 is the resistance value of the variable resistor VR1. "*" is a symbol representing multiplication.
Formula 2: V D =V s *(FR2+VR1)/(FR1+FR2+VR1)
　増幅回路１７０ｂは、抵抗ＦＲ３と、抵抗ＦＲ４と、オペアンプ１７５と、を含む。オペアンプ１７５は、第１入力端子１７５ａと、第２入力端子１７５ｂと、出力端子１７５ｃと、を含む。第１入力端子１７５ａには、分圧電圧ＶDが入力される。第２入力端子１７５ｂは、抵抗ＦＲ３を介して出力端子１７５ｃに接続されている。第２入力端子１７５ｂは、抵抗ＦＲ４を介して基準電位に接続されている。また、出力端子１７５ｃと、抵抗ＦＲ３と、抵抗ＦＲ４と、基準電位とが、この順に接続されている。増幅回路１７０ｂは、分圧電圧ＶDに基づいて第２センサ電圧ＶMを生成し、出力端子１７５ｃから第２センサ電圧ＶMを出力する。第２センサ電圧ＶMは、以下の数式３により与えられる。ここで、ＦＲ３は、抵抗ＦＲ３の抵抗値である。ＦＲ４は、抵抗ＦＲ４の抵抗値である。
　数式３：ＶM＝ＶD＊（ＦＲ３＋ＦＲ４）／ＦＲ４ The amplifier circuit 170b includes a resistor FR3, a resistor FR4, and an operational amplifier 175. The operational amplifier 175 includes a first input terminal 175a, a second input terminal 175b, and an output terminal 175c. The divided voltage V D is input to the first input terminal 175a. The second input terminal 175b is connected to the output terminal 175c via the resistor FR3. The second input terminal 175b is connected to the reference potential via the resistor FR4. Further, the output terminal 175c, the resistor FR3, the resistor FR4, and the reference potential are connected in this order. The amplifier circuit 170b generates the second sensor voltage V M based on the divided voltage V D , and outputs the second sensor voltage V M from the output terminal 175c. The second sensor voltage V M is given by Equation 3 below. Here, FR3 is the resistance value of the resistor FR3. FR4 is the resistance value of the resistor FR4.
Formula 3: V M =V D *(FR3+FR4)/FR4
　具体的には、第１入力端子１７５ａは、非反転増幅端子である。第２入力端子１７５ｂは、反転増幅端子である。 Specifically, the first input terminal 175a is a non-inverting amplifier terminal. The second input terminal 175b is an inverting amplification terminal.
　第２センサ電圧ＶMは、接続点ｐｓに供給される。その後、接続点ｐｓの電圧は、第１の実施形態と同様に利用される。 The second sensor voltage V M is supplied to the connection point ps. After that, the voltage at the connection point ps is used in the same manner as in the first embodiment.
　図１２に示す例では、分圧回路１７０ａは、可変抵抗ＶＲ１を含んでいる。可変パラメータは、可変抵抗ＶＲ１の抵抗値である。可変抵抗ＶＲ１の抵抗値の調整により、分圧電圧ＶDおよび第２センサ電圧ＶMを調整できる。 In the example shown in FIG. 12, the voltage dividing circuit 170a includes a variable resistor VR1. The variable parameter is the resistance value of the variable resistor VR1. By adjusting the resistance value of the variable resistor VR1, the divided voltage V D and the second sensor voltage V M can be adjusted.
　なお、抵抗ＦＲ１または抵抗ＦＲ２を可変抵抗としてもよい。このようにしても、可変抵抗の抵抗値の調整により、分圧電圧ＶDおよび第２センサ電圧ＶMを調整できる。 The resistor FR1 or the resistor FR2 may be a variable resistor. Even in this case, the divided voltage V D and the second sensor voltage V M can be adjusted by adjusting the resistance value of the variable resistor.
　また、分圧回路１７０ａではなく増幅回路１７０ｂに可変抵抗を含ませてもよい。具体的には、抵抗ＦＲ３または抵抗ＦＲ４を可変抵抗としてもよい。このようにしても、可変抵抗の抵抗値の調整により、第２センサ電圧ＶMを調整できる。 Further, the variable resistor may be included in the amplifier circuit 170b instead of the voltage divider circuit 170a. Specifically, the resistor FR3 or the resistor FR4 may be a variable resistor. Even in this case, the second sensor voltage V M can be adjusted by adjusting the resistance value of the variable resistor.
　第１の実施形態と同様、第２の実施形態では、以下に説明する（ｉ）の出力電圧－出力電力特性および（ii）の出力電流－出力電力特性がもたらされるように、センサ出力が相対的に小さいときに第１フィードバック制御が実行されるとともにセンサ出力が相対的に大きいときに第２フィードバック制御が実行される。上述のとおり、センサ出力は、具体的には第１センサ電圧Ｖsである。 Similar to the first embodiment, in the second embodiment, the sensor outputs are relative so that the output voltage-output power characteristic (i) and the output current-output power characteristic (ii) described below are provided. When the sensor output is relatively small, the first feedback control is executed, and when the sensor output is relatively large, the second feedback control is executed. As described above, the sensor output is specifically the first sensor voltage V s .
　（ｉ）の出力電圧－出力電力特性は、特性変換回路４００の出力電圧がある値であるときに特性変換回路４００の出力電力が最大となる出力電圧－出力電力特性である。（ii）の出力電流－出力電力特性は、特性変換回路４００の出力電流が切替電流ｉswであるときに特性変換回路４００の出力電力が最大となる出力電流－出力電力特性である。ここで、切替電流ｉswは、第１フィードバック制御と第２フィードバック制御とが切り替わるときの特性変換回路４００の出力電流である。上記のある値は、具体的には、第１の実施形態と同様、所定範囲内の値である。 The output voltage-output power characteristic of (i) is an output voltage-output power characteristic in which the output power of the characteristic conversion circuit 400 becomes maximum when the output voltage of the characteristic conversion circuit 400 has a certain value. The output current-output power characteristic (ii) is an output current-output power characteristic in which the output power of the characteristic conversion circuit 400 is maximum when the output current of the characteristic conversion circuit 400 is the switching current isw . Here, the switching current isw is the output current of the characteristic conversion circuit 400 when the first feedback control and the second feedback control are switched. The above-mentioned certain value is specifically a value within a predetermined range, as in the first embodiment.
　本実施形態では、切替電流ｉswは、電流センサ１２８による特性変換回路４００の出力電流の検出の誤差に依存するとともに、可変パラメータを変化させると変化する。 In the present embodiment, the switching current isw depends on the error in the detection of the output current of the characteristic conversion circuit 400 by the current sensor 128 and changes when the variable parameter is changed.
　電流センサ１２８に個体ばらつきがあると、電流センサ１２８の検出に誤差が生じ得る。つまり、センサ出力に誤差が生じ得る。誤差を有するセンサ出力が特性変換回路４００における制御に用いられると、切替電流ｉswが目標値（以下、目標電流と称することがある）からずれるおそれがある。切替電流ｉswがずれると、最大電力点が目標点からずれるおそれがある。最大電力点がずれると、特性変換回路４００の最大電力が目標値（以下、目標電力と称することがある）からずれるおそれがある。 If the current sensor 128 has individual variation, an error may occur in the detection of the current sensor 128. That is, an error may occur in the sensor output. If the sensor output having an error is used for control in the characteristic conversion circuit 400, the switching current isw may deviate from a target value (hereinafter, may be referred to as a target current). If the switching current isw shifts, the maximum power point may deviate from the target point. If the maximum power point shifts, the maximum power of the characteristic conversion circuit 400 may deviate from a target value (hereinafter, sometimes referred to as target power).
　この点、第２の実施形態によれば、可変パラメータを変化させることにより、切替電流ｉswを調整できる。これにより、切替電流ｉswの目標電流からのずれを小さくし、最大電力点の目標点からのずれを小さくし、最大電力の目標電力からのずれを小さくすることができる。また、可変パラメータを調整して切替電流ｉswを調整することにより、状況に応じて特性変換回路４００の最大電力を調整することも可能である。例えば、直流電力変換装置２０に接続された太陽光発電システムの発電電力が小さい場合には上記最大電力を大きくし、太陽光発電システムの発電電力が大きい場合には上記最大電力を小さくすることができる。また、燃料電池発電システム４０の最大出力電力は、例えば燃料電池４１のスタックの経年劣化等によって、低下する場合がある。そのような場合に、特性変換回路４００から出力される最大電力を低下させることによって、該最大電力を燃料電池発電システム４０が供給可能な範囲内に収めることができる。 In this respect, according to the second embodiment, the switching current isw can be adjusted by changing the variable parameter. This makes it possible to reduce the deviation of the switching current isw from the target current, decrease the deviation of the maximum power point from the target point, and decrease the deviation of the maximum power from the target power. Further, it is also possible to adjust the maximum power of the characteristic conversion circuit 400 according to the situation by adjusting the variable current and adjusting the switching current isw . For example, when the generated power of the photovoltaic power generation system connected to the DC power converter 20 is small, the maximum power may be increased, and when the generated power of the photovoltaic power generation system is large, the maximum power may be decreased. it can. Further, the maximum output power of the fuel cell power generation system 40 may decrease due to, for example, aging deterioration of the stack of the fuel cell 41. In such a case, by reducing the maximum power output from the characteristic conversion circuit 400, the maximum power can be kept within a range that the fuel cell power generation system 40 can supply.
　最大電力の目標電力からのずれを小さくすることにより、ＭＰＰＴ制御により特性変換回路４００から電力を取り出すときに、取り出される電力の目標電力からのずれを小さくすることができる。状況に応じて特性変換回路４００の最大電力を調整することにより、ＭＰＰＴ制御により特性変換回路４００から電力を取り出すときに、取り出される電力を状況に応じた値に調整することができる。例えば、直流電力変換装置２０に接続された太陽光発電システムの発電電力が小さい場合には取り出される電力を大きくし、太陽光発電システムの発電電力が大きい場合には上記取り出される電力を小さくすることができる。また、燃料電池発電システム４０の最大出力電力が低下した場合に、上記取り出される電力を小さくすることができる。 By reducing the deviation of the maximum power from the target power, it is possible to reduce the deviation of the extracted power from the target power when extracting the power from the characteristic conversion circuit 400 by MPPT control. By adjusting the maximum power of the characteristic conversion circuit 400 according to the situation, when the power is extracted from the characteristic conversion circuit 400 by the MPPT control, the extracted power can be adjusted to a value according to the situation. For example, when the generated power of the photovoltaic power generation system connected to the DC power converter 20 is small, the extracted power is increased, and when the generated power of the photovoltaic power generation system is large, the extracted power is reduced. You can Further, when the maximum output power of the fuel cell power generation system 40 decreases, the extracted power can be reduced.
［電流センサ１２８の個体ばらつきとその抑制］
　上述のとおり、電流センサ１２８には、個体ばらつきがあることがある。図１３から図１５を参照しつつ、個体ばらつきの影響について、詳細に説明する。 [Individual variation of current sensor 128 and its suppression]
As described above, the current sensor 128 may have individual variations. The effect of individual variation will be described in detail with reference to FIGS. 13 to 15.
　本実施形態では、電流センサ１２８は、図５に示した構成を有する。シャント抵抗１２８ｒの抵抗値Ｒsense、ゲインＧおよびバイアス電圧Ｖbiasは、理想的には基準値である。しかし、抵抗値Ｒsense、ゲインＧおよび／またはバイアス電圧Ｖbiasには、公差の範囲の誤差があり得る。本実施形態では、電流センサ１２８は、シャント抵抗１２８ｒの抵抗値が基準値よりも大きいときには、シャント抵抗１２８ｒの抵抗値が基準値であるときに比べ、大きい第１センサ電圧Ｖ１を出力するように構成されている。電流センサ１２８は、ゲインＧが基準値よりも大きいときには、ゲインＧが基準値であるときに比べ、大きい第１センサ電圧Ｖ１を出力するように構成されている。電流センサ１２８は、バイアス電圧Ｖbiasが基準値よりも大きいときには、バイアス電圧Ｖbiasが基準値であるときに比べ、大きい第１センサ電圧Ｖ１を出力するように構成されている。 In the present embodiment, the current sensor 128 has the configuration shown in FIG. The resistance value R sense of the shunt resistor 128r, the gain G, and the bias voltage V bias are ideally reference values. However, the resistance value R sense , the gain G, and/or the bias voltage V bias may have an error in the tolerance range. In the present embodiment, the current sensor 128 outputs a larger first sensor voltage V1 when the resistance value of the shunt resistor 128r is larger than the reference value, compared to when the resistance value of the shunt resistor 128r is the reference value. It is configured. The current sensor 128 is configured to output a larger first sensor voltage V1 when the gain G is larger than the reference value, compared to when the gain G is the reference value. Current sensor 128, when the bias voltage V bias is larger than the reference value, than when the bias voltage V bias is the reference value, and is configured to output a large first sensor voltage V1.
　図１３において、横軸は、特性変換回路４００の出力電流を示す。図１３では、抵抗値ＲsenseおよびゲインＧが基準値にある場合において、バイアス電圧Ｖbiasを変化させた場合の特性変換回路４００の出力特性を示す。 In FIG. 13, the horizontal axis represents the output current of the characteristic conversion circuit 400. FIG. 13 shows the output characteristic of the characteristic conversion circuit 400 when the bias voltage V bias is changed when the resistance value R sense and the gain G are at the reference values.
　具体的には、図１３において、「特性変換回路の出力電圧（０）」は、バイアス電圧Ｖbiasが基準値であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電圧（Ａ）」は、バイアス電圧Ｖbiasが基準値の１０１％であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電圧（Ｂ）」は、バイアス電圧Ｖbiasが基準値の９９％であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電圧（Ｃ）」は、バイアス電圧Ｖbiasが基準値の１０２％であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電圧（Ｄ）」は、バイアス電圧Ｖbiasが基準値の９８％であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電力（０）」は、バイアス電圧Ｖbiasが基準値であるときの、特性変換回路４００の出力電力を示す。「特性変換回路の出力電力（Ａ）」は、バイアス電圧Ｖbiasが基準値の１０１％であるときの、特性変換回路４００の出力電力を示す。「特性変換回路の出力電力（Ｂ）」は、バイアス電圧Ｖbiasが基準値の９９％であるときの、特性変換回路４００の出力電力を示す。「特性変換回路の出力電力（Ｃ）」は、バイアス電圧Ｖbiasが基準値の１０２％であるときの、特性変換回路４００の出力電力を示す。「特性変換回路の出力電力（Ｄ）」は、バイアス電圧Ｖbiasが基準値の９８％であるときの、特性変換回路４００の出力電力を示す。図１３において、上下に延びる５本の点線は、それぞれ、左から順に、切替電流ｉsw（Ｃ）、切替電流ｉsw（Ａ）、切替電流ｉsw（０）、切替電流ｉsw（Ｂ）および切替電流ｉsw（Ｄ）を表す。「切替電流ｉsw（０）」は、バイアス電圧Ｖbiasが基準値であるときの、切替電流ｉswを示す。「切替電流ｉsw（Ａ）」は、バイアス電圧Ｖbiasが基準値の１０１％であるときの、切替電流ｉswを示す。「切替電流ｉsw（Ｂ）」は、バイアス電圧Ｖbiasが基準値の９９％であるときの、切替電流ｉswを示す。「切替電流ｉsw（Ｃ）」は、バイアス電圧Ｖbiasが基準値の１０２％であるときの、切替電流ｉswを示す。「切替電流ｉsw（Ｄ）」は、バイアス電圧Ｖbiasが基準値の９８％であるときの、切替電流ｉswを示す。上述のとおり、切替電流ｉswは、第１フィードバック制御と第２フィードバック制御とが切り替わるときの特性変換回路４００の出力電流である。 Specifically, in FIG. 13, “output voltage (0) of characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the bias voltage V bias is a reference value. The “output voltage (A) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the bias voltage V bias is 101% of the reference value. The “output voltage (B) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the bias voltage V bias is 99% of the reference value. The “output voltage (C) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the bias voltage V bias is 102% of the reference value. The “output voltage (D) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the bias voltage V bias is 98% of the reference value. The “output power (0) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the bias voltage V bias is a reference value. The “output power (A) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the bias voltage V bias is 101% of the reference value. The “output power (B) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the bias voltage V bias is 99% of the reference value. The “output power (C) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the bias voltage V bias is 102% of the reference value. The “output power (D) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the bias voltage V bias is 98% of the reference value. In FIG. 13, five dotted lines extending vertically are the switching current isw (C), the switching current isw (A), the switching current isw (0), and the switching current isw (B) in order from the left. And the switching current i sw (D). "Switching current isw (0)" indicates the switching current isw when the bias voltage Vbias is a reference value. “Switching current isw (A)” indicates the switching current isw when the bias voltage V bias is 101% of the reference value. "Switching current isw (B)" indicates the switching current isw when the bias voltage Vbias is 99% of the reference value. "Switching current isw (C)" indicates the switching current isw when the bias voltage Vbias is 102% of the reference value. "Switching current isw (D)" indicates the switching current isw when the bias voltage Vbias is 98% of the reference value. As described above, the switching current isw is the output current of the characteristic conversion circuit 400 when the first feedback control and the second feedback control are switched.
　図１３から、バイアス電圧Ｖbiasの変動に伴い切替電流ｉswが変動していることが理解される。 From FIG. 13, it is understood that the switching current isw fluctuates as the bias voltage Vbias fluctuates.
　バイアス電圧Ｖbiasが基準値であるとき、最大電力点は、目標点にある。この状況は、第１の実施形態に関する図３Ａに示したとおりである。 When the bias voltage V bias is the reference value, the maximum power point is at the target point. This situation is as shown in FIG. 3A for the first embodiment.
　バイアス電圧Ｖbiasが基準値にあるとき、切替電流ｉswは、目標電流に一致する。バイアス電圧Ｖbiasが基準値よりも大きいと、バイアス電圧Ｖbiasが基準値にあるときに比べ、切替電流ｉswは小さい。反対に、バイアス電圧Ｖbiasが基準値よりも小さいと、バイアス電圧Ｖbiasが基準値にあるときに比べ、切替電流ｉswは大きい。 When the bias voltage V bias is at the reference value, the switching current isw matches the target current. When the bias voltage V bias is larger than the reference value, the switching current isw is smaller than when the bias voltage V bias is at the reference value. On the contrary, when the bias voltage V bias is smaller than the reference value, the switching current i sw is larger than when the bias voltage V bias is at the reference value.
　バイアス電圧Ｖbiasが基準値にあるとき、特性変換回路４００の最大電力は、目標電力に一致する。バイアス電圧Ｖbiasが基準値よりも大きいと、バイアス電圧Ｖbiasが基準値にあるときに比べ、最大電力は小さい。反対に、バイアス電圧Ｖbiasが基準値よりも小さいと、バイアス電圧Ｖbiasが基準値にあるときに比べ、最大電力は大きい。 When the bias voltage V bias is at the reference value, the maximum power of the characteristic conversion circuit 400 matches the target power. When the bias voltage V bias is larger than the reference value, the maximum power is smaller than when the bias voltage V bias is at the reference value. On the contrary, when the bias voltage V bias is smaller than the reference value, the maximum power is larger than when the bias voltage V bias is at the reference value.
　図１３に示されているように、バイアス電圧Ｖbiasの個体ばらつきは、特性変換回路４００の最大電力点のばらつきをもたらす。最大電力点のばらつきは、切替電流ｉswおよび最大電力のばらつきをもたらす。 As shown in FIG. 13, individual variations in the bias voltage V bias cause variations in the maximum power point of the characteristic conversion circuit 400. The variation of the maximum power point causes the variation of the switching current isw and the maximum power.
　この点、第２の実施形態では、可変抵抗ＶＲ１の抵抗値を調整することにより、特性変換回路４００の切替電流ｉswを調整し、最大電力を調整することができる。 In this respect, in the second embodiment, the maximum electric power can be adjusted by adjusting the resistance value of the variable resistor VR1 to adjust the switching current isw of the characteristic conversion circuit 400.
　例えば、バイアス電圧Ｖbiasが基準値よりも小さく、バイアス電圧Ｖbiasが基準値にあるときに比べ、切替電流ｉswおよび最大電力が大きい場合を考える。この場合、可変抵抗ＶＲ１の抵抗値を調整することによってバイアス電圧Ｖbiasが基準値にある場合に比べて第２センサ電圧ＶMを大きくすることにより、切替電流ｉswおよび最大電力を小さくすることができる。これにより、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。具体的には、可変抵抗ＶＲ１の抵抗値を大きくすることによって、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。 For example, consider a case where the bias voltage V bias is smaller than the reference value and the switching current isw and maximum power are larger than when the bias voltage V bias is at the reference value. In this case, the switching current i sw and the maximum power are reduced by adjusting the resistance value of the variable resistor VR1 to increase the second sensor voltage V M as compared with the case where the bias voltage V bias is at the reference value. You can As a result, the switching current isw and the maximum power can be brought close to the target current and the target power. Specifically, by increasing the resistance value of the variable resistor VR1, the switching current isw and the maximum power can be brought close to the target current and the target power.
　反対に、バイアス電圧Ｖbiasが基準値よりも大きく、バイアス電圧Ｖbiasが基準値にあるときに比べ、切替電流ｉswおよび最大電力が小さい場合を考える。この場合、可変抵抗ＶＲ１の抵抗値を調整することによってバイアス電圧Ｖbiasが基準値にある場合に比べて第２センサ電圧ＶMを小さくすることにより、切替電流ｉswおよび最大電力を大きくすることができる。これにより、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。具体的には、可変抵抗ＶＲ１の抵抗値を小さくすることによって、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。 On the contrary, consider a case where the bias voltage V bias is larger than the reference value and the switching current isw and the maximum power are smaller than when the bias voltage V bias is at the reference value. In this case, the switching current i sw and the maximum power are increased by adjusting the resistance value of the variable resistor VR1 to reduce the second sensor voltage V M as compared with the case where the bias voltage V bias is at the reference value. You can As a result, the switching current isw and the maximum power can be brought close to the target current and the target power. Specifically, by reducing the resistance value of the variable resistor VR1, the switching current isw and the maximum power can be brought close to the target current and the target power.
　可変抵抗ＶＲ１の調整により、切替電流ｉswおよび最大電力を、バイアス電圧Ｖbiasが基準値にあるときの値に近づけることができる。つまり、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。概括的にいうと、特性変換回路４００の出力特性を、バイアス電圧Ｖbiasが基準値にあるときのものに近づけることができる。 By adjusting the variable resistor VR1, the switching current i sw and the maximum power can be brought close to the values when the bias voltage V bias is at the reference value. That is, the switching current isw and the maximum power can be brought close to the target current and the target power. Generally speaking, the output characteristic of the characteristic conversion circuit 400 can be brought close to that when the bias voltage V bias is at the reference value.
　ゲインＧおよびバイアス電圧Ｖbiasの両方に誤差がある場合においても、可変抵抗ＶＲ１の抵抗値を調整することにより、特性変換回路４００の切替電流ｉswを調整し、最大電力を調整することができる。 Even when there is an error in both the gain G and the bias voltage V bias , the switching current isw of the characteristic conversion circuit 400 can be adjusted by adjusting the resistance value of the variable resistor VR1, and the maximum power can be adjusted. ..
　図１４および図１５において、横軸は、特性変換回路４００の出力電流を示す。図１４および図１５では、シャント抵抗１２８ｒの抵抗値Ｒsenseが基準値にある場合において、ゲインＧおよびバイアス電圧Ｖbiasを変化させた場合の特性変換回路４００の出力特性を示す。 14 and 15, the horizontal axis represents the output current of the characteristic conversion circuit 400. 14 and 15 show the output characteristics of the characteristic conversion circuit 400 when the gain G and the bias voltage V bias are changed when the resistance value R sense of the shunt resistor 128r is at the reference value.
　具体的には、図１４において、「特性変換回路の出力電圧（０）」は、ゲインＧおよびバイアス電圧Ｖbiasが基準値であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電圧（Ｅ）」は、ゲインＧが基準値の１０１％でありかつバイアス電圧Ｖbiasが基準値の１０２％であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電圧（Ｆ）」は、ゲインＧが基準値の９９％でありかつバイアス電圧Ｖbiasが基準値の９８％であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電力（０）」は、ゲインＧおよびバイアス電圧Ｖbiasが基準値であるときの、特性変換回路４００の出力電力を示す。「特性変換回路の出力電力（Ｅ）」は、ゲインＧが基準値の１０１％でありかつバイアス電圧Ｖbiasが基準値の１０２％であるときの、特性変換回路４００の出力電力を示す。「特性変換回路の出力電力（Ｆ）」は、ゲインＧが基準値の９９％でありかつバイアス電圧Ｖbiasが基準値の９８％であるときの、特性変換回路４００の出力電力を示す。「切替電流ｉsw（０）」は、ゲインＧおよびバイアス電圧Ｖbiasが基準値であるときの、切替電流ｉswを示す。「切替電流ｉsw（Ｅ）」は、ゲインＧが基準値の１０１％でありかつバイアス電圧Ｖbiasが基準値の１０２％であるときの、切替電流ｉswを示す。「切替電流ｉsw（Ｆ）」は、ゲインＧが基準値の９９％でありかつバイアス電圧Ｖbiasが基準値の９８％であるときの、切替電流ｉswを示す。 Specifically, in FIG. 14, “output voltage (0) of characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the gain G and the bias voltage V bias are reference values. The “output voltage (E) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the gain G is 101% of the reference value and the bias voltage V bias is 102% of the reference value. The “output voltage (F) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the gain G is 99% of the reference value and the bias voltage V bias is 98% of the reference value. The “output power (0) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G and the bias voltage V bias are reference values. The “output power (E) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G is 101% of the reference value and the bias voltage V bias is 102% of the reference value. The “output power (F) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G is 99% of the reference value and the bias voltage V bias is 98% of the reference value. "Switching current isw (0)" indicates the switching current isw when the gain G and the bias voltage Vbias are reference values. "Switching current i sw (E)" is when the gain G is 101% of the reference value and the bias voltage V bias is 102% of the reference value, indicating the switching current i sw. "Switching current i sw (F)" is when the gain G is 99% of the reference value and the bias voltage V bias is 98% of the reference value, indicating the switching current i sw.
　また、図１５において、「特性変換回路の出力電圧（０）」は、ゲインＧおよびバイアス電圧Ｖbiasが基準値であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電圧（Ｇ）」は、ゲインＧが基準値の９９％でありかつバイアス電圧Ｖbiasが基準値の１０２％であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電圧（Ｈ）」は、ゲインＧが基準値の１０１％でありかつバイアス電圧Ｖbiasが基準値の９８％であるときの、特性変換回路４００の出力電圧を示す。「特性変換回路の出力電力（０）」は、ゲインＧおよびバイアス電圧Ｖbiasが基準値であるときの、特性変換回路４００の出力電力を示す。「特性変換回路の出力電力（Ｇ）」は、ゲインＧが基準値の９９％でありかつバイアス電圧Ｖbiasが基準値の１０２％であるときの、特性変換回路４００の出力電力を示す。「特性変換回路の出力電力（Ｈ）」は、ゲインＧが基準値の１０１％でありかつバイアス電圧Ｖbiasが基準値の９８％であるときの、特性変換回路４００の出力電力を示す。「切替電流ｉsw（０）」は、ゲインＧおよびバイアス電圧Ｖbiasが基準値であるときの、切替電流ｉswを示す。「切替電流ｉsw（Ｇ）」は、ゲインＧが基準値の９９％でありかつバイアス電圧Ｖbiasが基準値の１０２％であるときの、切替電流ｉswを示す。「切替電流ｉsw（Ｈ）」は、ゲインＧが基準値の１０１％でありかつバイアス電圧Ｖbiasが基準値の９８％であるときの、切替電流ｉswを示す。 Further, in FIG. 15, “output voltage (0) of characteristic conversion circuit” indicates an output voltage of the characteristic conversion circuit 400 when the gain G and the bias voltage V bias are reference values. The “output voltage (G) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the gain G is 99% of the reference value and the bias voltage V bias is 102% of the reference value. The “output voltage (H) of the characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 400 when the gain G is 101% of the reference value and the bias voltage V bias is 98% of the reference value. The “output power (0) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G and the bias voltage V bias are reference values. The “output power (G) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G is 99% of the reference value and the bias voltage V bias is 102% of the reference value. The “output power (H) of the characteristic conversion circuit” indicates the output power of the characteristic conversion circuit 400 when the gain G is 101% of the reference value and the bias voltage V bias is 98% of the reference value. "Switching current isw (0)" indicates the switching current isw when the gain G and the bias voltage Vbias are reference values. "Switching current i sw (G)" is when the gain G is 99% of the reference value and the bias voltage V bias is 102% of the reference value, indicating the switching current i sw. "Switching current i sw (H)" is obtained when the gain G is 101% of the reference value and the bias voltage V bias is 98% of the reference value, indicating the switching current i sw.
　図１４および図１５から、ゲインＧおよびバイアス電圧Ｖbiasの変動に伴い切替電流ｉswが変動していることが理解される。しかしながら、図１４の例においても、図１５の例においても、可変抵抗ＶＲ１の抵抗値を調整することによって、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。概括的にいうと、特性変換回路４００の出力特性を、ゲインＧおよびバイアス電圧Ｖbiasが基準値にあるときのものに近づけることができる。 It is understood from FIGS. 14 and 15 that the switching current isw fluctuates as the gain G and the bias voltage Vbias fluctuate. However, in both the example of FIG. 14 and the example of FIG. 15, the switching current isw and the maximum power can be brought close to the target current and the target power by adjusting the resistance value of the variable resistor VR1. Generally speaking, the output characteristic of the characteristic conversion circuit 400 can be brought close to that when the gain G and the bias voltage V bias are at the reference values.
　具体的には、図１４の（Ｅ）の場合、可変抵抗ＶＲ１の抵抗値を小さくして第２センサ電圧ＶMを小さくすることによって、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。 Specifically, in the case of FIG. 14 (E), by reducing the second sensor voltage V M to reduce the resistance of the variable resistor VR1, the switching current i sw and maximum power, the target current and target power Can be approached.
　図１４の（Ｆ）の場合、可変抵抗ＶＲ１の抵抗値を大きくして第２センサ電圧ＶMを大きくすることによって、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。 In the case of FIG. 14F, by increasing the resistance value of the variable resistor VR1 and increasing the second sensor voltage V M , the switching current isw and the maximum power can be brought close to the target current and the target power. ..
　図１５の（Ｇ）の場合、可変抵抗ＶＲ１の抵抗値を小さくして第２センサ電圧ＶMを小さくすることによって、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。 If 15 of the (G), by reducing the second sensor voltage V M to reduce the resistance of the variable resistor VR1, the switching current i sw and maximum power can be brought close to the target current and target power ..
　図１５の（Ｈ）の場合、可変抵抗ＶＲ１の抵抗値を大きくして第２センサ電圧ＶMを大きくすることによって、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。 If 15 of the (H), by increasing the second sensor voltage V M to increase the resistance value of the variable resistor VR1, the switching current i sw and maximum power can be brought close to the target current and target power ..
　当然ではあるが、抵抗値Ｒsenseに誤差がある場合も、可変抵抗ＶＲ１の抵抗値を調整することによって、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。 As a matter of course, even when the resistance value R sense has an error, the switching current isw and the maximum power can be brought close to the target current and the target power by adjusting the resistance value of the variable resistor VR1.
　第２の実施形態の技術は、第１の実施形態の図４のみならず、図８から図１０の構成にも適用可能である。具体的には、調整器１７０は、図８から図１０の構成にも適用可能である。 The technique of the second embodiment is applicable not only to the configuration of FIG. 4 of the first embodiment but also to the configurations of FIGS. 8 to 10. Specifically, the adjuster 170 is also applicable to the configurations of FIGS. 8 to 10.
（第３の実施形態）
　以下、本開示の第３の実施形態について説明する。以下では、第１の実施形態と同様の部分については、同一符号を付し、説明を省略することがある。 (Third Embodiment)
Hereinafter, the third embodiment of the present disclosure will be described. In the following, the same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof may be omitted.
　図１６および図１７は、第３の実施形態に係る電力システム５００のブロック図である。具体的には、図１６は、系統連系時の電力の流れの例を示している。図１７は、停電時の電力の流れの例を示している。 16 and 17 are block diagrams of a power system 500 according to the third embodiment. Specifically, FIG. 16 shows an example of the flow of electric power during grid interconnection. FIG. 17 shows an example of the flow of electric power at the time of power failure.
　図１６および図１７に示すように、電力システム５００は、基板５６０を有している。基板５６０は、燃料電池発電システム４０とパワーステーション１０とを接続する経路上に設けられている。基板５６０には、燃料電池発電システム４０から、具体的には第２ＤＣバス４３から、直流電力が供給される。基板５６０は、特性変換回路６００と、ＬＣフィルタ６１と、保護リレー６２と、を有する。 As shown in FIGS. 16 and 17, the power system 500 has a board 560. The substrate 560 is provided on the path connecting the fuel cell power generation system 40 and the power station 10. Direct current power is supplied to the substrate 560 from the fuel cell power generation system 40, specifically from the second DC bus 43. The substrate 560 has a characteristic conversion circuit 600, an LC filter 61, and a protection relay 62.
　特性変換回路６００は、燃料電池発電システム４０と直流電力変換装置２０とを接続する経路上、詳細には直流電力の経路上、に設けられている。特性変換回路６００は、特性変換制御を実行する。 The characteristic conversion circuit 600 is provided on the path connecting the fuel cell power generation system 40 and the DC power conversion device 20, specifically, on the path of DC power. The characteristic conversion circuit 600 executes characteristic conversion control.
　図１８および図１９に、特性変換回路６００の出力特性を示す。図２０に特性変換回路６００の例を示す。 18 and 19 show the output characteristics of the characteristic conversion circuit 600. FIG. 20 shows an example of the characteristic conversion circuit 600.
　第１の実施形態と同様、特性変換回路６００が行う特性変換制御は、特性変換回路６００の出力電圧がある値であるときに特性変換回路６００の出力電力が最大となる出力電圧－出力電力特性をもたらす。特性変換制御は、第１フィードバック制御および第２フィードバック制御を含む。第１フィードバック制御は、特性変換回路６００の出力電流が相対的に小さいときに行われる制御である。第２フィードバック制御は、特性変換回路６００の出力電流が相対的に大きいときに行われる制御である。第１フィードバック制御と第２フィードバック制御とが切り替わるときに、特性変換回路６００の出力電圧が上記ある値となる。 Similar to the first embodiment, the characteristic conversion control performed by the characteristic conversion circuit 600 is performed by the output voltage-output power characteristic in which the output power of the characteristic conversion circuit 600 becomes maximum when the output voltage of the characteristic conversion circuit 600 has a certain value. Bring The characteristic conversion control includes first feedback control and second feedback control. The first feedback control is control performed when the output current of the characteristic conversion circuit 600 is relatively small. The second feedback control is control performed when the output current of the characteristic conversion circuit 600 is relatively large. When the first feedback control and the second feedback control are switched, the output voltage of the characteristic conversion circuit 600 becomes the above certain value.
　図２０に示すように、特性変換回路６００は、電圧電流制御回路１６０と、電流センサ１２８と、調整器１８０と、を含む。 As shown in FIG. 20, the characteristic conversion circuit 600 includes a voltage/current control circuit 160, a current sensor 128, and a regulator 180.
　第１の実施形態と同様、電圧電流制御回路１６０は、ＤＣＤＣコンバータである。電圧電流制御回路１６０は、燃料電池発電システム４０と電流センサ１２８の間に設けられている。具体的には、電圧電流制御回路１６０は、第２ＤＣバス４３と電流センサ１２８の間に設けられている。 Like the first embodiment, the voltage/current control circuit 160 is a DCDC converter. The voltage/current control circuit 160 is provided between the fuel cell power generation system 40 and the current sensor 128. Specifically, the voltage/current control circuit 160 is provided between the second DC bus 43 and the current sensor 128.
　第１の実施形態と同様、電流センサ１２８は、特性変換回路６００の出力電流の検出を行う。電流センサ１２８は、その検出の結果を表すセンサ出力を出力する。電流センサ１２８は、特性変換回路６００の出力電流が大きくなるほどセンサ出力を大きく出力する。つまり、センサ出力は、特性変換回路６００の出力電流が大きくなるほど大きくなる。本実施形態では、センサ出力は、第１センサ電圧Ｖ１である。電流センサ１２８は、第１センサ電圧Ｖ１を出力するセンサ出力部１２８ａを含む。なお、第１センサ電圧Ｖ１は、第１の実施形態のセンサ電圧Ｖsに対応する。 Similar to the first embodiment, the current sensor 128 detects the output current of the characteristic conversion circuit 600. The current sensor 128 outputs a sensor output indicating the result of the detection. The current sensor 128 outputs a larger sensor output as the output current of the characteristic conversion circuit 600 increases. That is, the sensor output increases as the output current of the characteristic conversion circuit 600 increases. In the present embodiment, the sensor output is the first sensor voltage V1. The current sensor 128 includes a sensor output unit 128a that outputs the first sensor voltage V1. The first sensor voltage V1 corresponds to the sensor voltage V s of the first embodiment.
　調整器１８０は、可変パラメータを調整できるように構成されている。本実施形態では、調整器１８０は可変出力電源であり、可変パラメータは可変出力である。以下では、可変出力電源である調整器１８０を、可変出力電源１８０と表記することがある。 The adjuster 180 is configured to be able to adjust variable parameters. In this embodiment, the regulator 180 is a variable output power supply and the variable parameter is a variable output. Below, the regulator 180 which is a variable output power supply may be described as the variable output power supply 180.
　可変出力電源１８０は、可変出力を出力する。本実施形態では、可変出力は、可変電圧Ｖ４である。可変出力電源１８０は、例えば、制御器５１のデジタル－アナログポートである。 The variable output power supply 180 outputs a variable output. In this embodiment, the variable output is the variable voltage V4. The variable output power supply 180 is, for example, a digital-analog port of the controller 51.
　特性変換回路６００において、第１回路６１０と、第２回路６２０と、が設けられている。第１回路６１０は、センサ出力が大きくなるほど特性変換回路６００の出力電力を大きくする第１フィードバック制御を実行する。第２回路６２０は、センサ出力が大きくなるほど特性変換回路６００の出力電力を小さくする第２フィードバック制御を、第１回路６１０と協働して実行する。特性変換回路６００において、フィードバック電流供給部１３０も設けられている。 The characteristic conversion circuit 600 is provided with a first circuit 610 and a second circuit 620. The first circuit 610 executes the first feedback control in which the output power of the characteristic conversion circuit 600 increases as the sensor output increases. The second circuit 620 cooperates with the first circuit 610 to execute the second feedback control in which the output power of the characteristic conversion circuit 600 decreases as the sensor output increases. A feedback current supply unit 130 is also provided in the characteristic conversion circuit 600.
　第１回路６１０、第２回路６２０および電圧電流制御回路１６０は、協働して、特性変換制御を実行する。 The first circuit 610, the second circuit 620, and the voltage/current control circuit 160 cooperate to execute the characteristic conversion control.
　具体的には、第１回路６１０は、上記第１フィードバック制御を、電圧電流制御回路１６０と協働して実行する。第２回路は、第２フィードバック制御を、第１回路６１０および電圧電流制御回路１６０と協働して実行する。 Specifically, the first circuit 610 executes the first feedback control in cooperation with the voltage/current control circuit 160. The second circuit executes the second feedback control in cooperation with the first circuit 610 and the voltage/current control circuit 160.
　特性変換回路６００において、以下に説明する（ｉ）の出力電圧－出力電力特性および（ii）の出力電流－出力電力特性がもたらされるように、センサ出力が相対的に小さいときに第１フィードバック制御が実行されるとともにセンサ出力が相対的に大きいときに第２フィードバック制御が実行される。 In the characteristic conversion circuit 600, the first feedback control is performed when the sensor output is relatively small so that the output voltage-output power characteristic of (i) and the output current-output power characteristic of (ii) described below are provided. Is executed and the second feedback control is executed when the sensor output is relatively large.
　（ｉ）の出力電圧－出力電力特性は、図１８に示すような、特性変換回路６００の出力電圧がある値であるときに特性変換回路６００の出力電力が最大となる出力電圧－出力電力特性である。上記のある値は、具体的には、第１の実施形態と同様、所定範囲内の値である。 The output voltage-output power characteristic of (i) is the output voltage-output power characteristic in which the output power of the characteristic conversion circuit 600 becomes maximum when the output voltage of the characteristic conversion circuit 600 has a certain value as shown in FIG. Is. The above-mentioned certain value is specifically a value within a predetermined range, as in the first embodiment.
　上述のとおり、直流電力変換装置２０は、出力電圧が所定範囲内にあるときに出力電力が最大になる太陽光発電システムのＭＰＰＴ制御を実行できるように設計されている。本実施形態では、特性変換回路６００は、出力電圧がその所定範囲内の値であるときに出力電力が最大となる上記（ｉ）の出力電圧－出力電力特性を有する。燃料電池発電システムの出力電圧－出力電力特性は、ＭＰＰＴ制御による電力の取り出しに必ずしも適していない。しかし、上記（ｉ）の出力電圧－出力電力特性を有する特性変換回路６００は、直流電力変換装置２０を用いてＭＰＰＴ制御を実行することにより燃料電池発電システム４０から直流電力変換装置２０に電力を取り出すことを可能にする。 As described above, the DC power conversion device 20 is designed to be able to execute the MPPT control of the solar power generation system that maximizes the output power when the output voltage is within the predetermined range. In the present embodiment, the characteristic conversion circuit 600 has the output voltage-output power characteristic of (i) above in which the output power becomes maximum when the output voltage has a value within the predetermined range. The output voltage-output power characteristic of the fuel cell power generation system is not necessarily suitable for power extraction by MPPT control. However, the characteristic conversion circuit 600 having the output voltage-output power characteristic of the above (i) outputs power from the fuel cell power generation system 40 to the DC power converter 20 by executing the MPPT control using the DC power converter 20. Allow to take out.
　（ii）の出力電流－出力電力特性は、図１９に示すような、特性変換回路６００の出力電流が切替電流ｉswであるときに特性変換回路６００の出力電力が最大となる出力電流－出力電力特性である。ここで、切替電流ｉswは、第１フィードバック制御と第２フィードバック制御とが切り替わるときの特性変換回路６００の出力電流である。 The output current-output power characteristic of (ii) is the output current-output at which the output power of the characteristic conversion circuit 600 becomes maximum when the output current of the characteristic conversion circuit 600 is the switching current i sw as shown in FIG. It is a power characteristic. Here, the switching current isw is the output current of the characteristic conversion circuit 600 when the first feedback control and the second feedback control are switched.
　切替電流ｉswは、電流センサ１２８による特性変換回路６００の出力電流の検出の誤差に依存するとともに、可変パラメータを変化させると変化する。上述のとおり、可変パラメータは、本実施形態では可変出力であり、具体的には可変電圧Ｖ４である。 The switching current isw depends on the error in the detection of the output current of the characteristic conversion circuit 600 by the current sensor 128 and changes when the variable parameter is changed. As described above, the variable parameter is a variable output in this embodiment, and is specifically the variable voltage V4.
　電流センサ１２８に個体ばらつきがあると、電流センサ１２８の検出に誤差が生じ得る。つまり、センサ出力に誤差が生じ得る。誤差を有するセンサ出力が特性変換回路６００における制御に用いられると、切替電流ｉswが目標値（以下、目標電流と称することがある）からずれるおそれがある。切替電流ｉswがずれると、図１８および図１９に示す最大電力点が目標点からずれるおそれがある。最大電力点がずれると、特性変換回路６００の最大電力が目標値（以下、目標電力と称することがある）からずれるおそれがある。 If the current sensor 128 has individual variation, an error may occur in the detection of the current sensor 128. That is, an error may occur in the sensor output. If the sensor output having an error is used for control in the characteristic conversion circuit 600, the switching current isw may deviate from a target value (hereinafter, may be referred to as a target current). If the switching current isw shifts, the maximum power point shown in FIGS. 18 and 19 may deviate from the target point. If the maximum power point shifts, the maximum power of the characteristic conversion circuit 600 may deviate from a target value (hereinafter, sometimes referred to as target power).
　この点、本実施形態によれば、可変パラメータを変化させることにより、切替電流ｉswを調整できる。これにより、切替電流ｉswの目標電流からのずれを小さくし、最大電力点の目標点からのずれを小さくし、最大電力の目標電力からのずれを小さくすることができる。また、可変パラメータを調整して切替電流ｉswを調整することにより、状況に応じて特性変換回路６００の最大電力を調整することも可能である。例えば、直流電力変換装置２０に接続された太陽光発電システムの発電電力が小さい場合には上記最大電力を大きくし、太陽光発電システムの発電電力が大きい場合には上記最大電力を小さくすることができる。また、燃料電池発電システム４０の最大出力電力は、例えば燃料電池４１のスタックの経年劣化等によって、低下する場合がある。そのような場合に、特性変換回路６００から出力される最大電力を低下させることによって、該最大電力を燃料電池発電システム４０が供給可能な範囲内に収めることができる。 In this respect, according to the present embodiment, the switching current isw can be adjusted by changing the variable parameter. This makes it possible to reduce the deviation of the switching current isw from the target current, decrease the deviation of the maximum power point from the target point, and decrease the deviation of the maximum power from the target power. Further, by adjusting the variable parameter to adjust the switching current isw , it is possible to adjust the maximum power of the characteristic conversion circuit 600 according to the situation. For example, when the generated power of the photovoltaic power generation system connected to the DC power converter 20 is small, the maximum power may be increased, and when the generated power of the photovoltaic power generation system is large, the maximum power may be decreased. it can. Further, the maximum output power of the fuel cell power generation system 40 may decrease due to, for example, aging deterioration of the stack of the fuel cell 41. In such a case, by reducing the maximum electric power output from the characteristic conversion circuit 600, the maximum electric power can be kept within a range that the fuel cell power generation system 40 can supply.
　最大電力の目標電力からのずれを小さくすることにより、ＭＰＰＴ制御により特性変換回路６００から電力を取り出すときに、取り出される電力の目標電力からのずれを小さくすることができる。状況に応じて特性変換回路６００の最大電力を調整することにより、ＭＰＰＴ制御により特性変換回路６００から電力を取り出すときに、取り出される電力を状況に応じた値に調整することができる。例えば、直流電力変換装置２０に接続された太陽光発電システムの発電電力が小さい場合には取り出される電力を大きくし、太陽光発電システムの発電電力が大きい場合には上記取り出される電力を小さくすることができる。また、燃料電池発電システム４０の最大出力電力が低下した場合に、上記取り出される電力を小さくすることができる。 By reducing the deviation of the maximum power from the target power, it is possible to reduce the deviation of the extracted power from the target power when extracting the power from the characteristic conversion circuit 600 by MPPT control. By adjusting the maximum power of the characteristic conversion circuit 600 according to the situation, when the power is extracted from the characteristic conversion circuit 600 by the MPPT control, the extracted power can be adjusted to a value according to the situation. For example, when the generated power of the photovoltaic power generation system connected to the DC power converter 20 is small, the extracted power is increased, and when the generated power of the photovoltaic power generation system is large, the extracted power is reduced. You can Further, when the maximum output power of the fuel cell power generation system 40 decreases, the extracted power can be reduced.
　典型的には、特性変換回路６００出力電圧－出力電力特性は、出力電圧に対して出力電力が単一ピークを有する特性である。上記（i）の出力電圧－出力電力特性は、そのような特性を示している。 Typically, the characteristic conversion circuit 600 output voltage-output power characteristic is a characteristic in which the output power has a single peak with respect to the output voltage. The output voltage-output power characteristic of the above (i) shows such a characteristic.
　特性変換回路６００の出力特性について、さらに説明する。 The output characteristics of the characteristic conversion circuit 600 will be further described.
　図１８において、実線は、特性変換回路６００の出力電圧と特性変換回路６００の出力電力との関係すなわち出力電圧－出力電力特性を表す。短破線は、特性変換回路６００の出力電圧と特性変換回路６００の出力電流との関係すなわち出力電圧－出力電流特性を表す。一点鎖線は、第１フィードバック制御の寄与を表す。二点鎖線は、第２フィードバック制御の寄与を表す。長破線は、第１センサ電圧Ｖ１を表す。 In FIG. 18, the solid line represents the relationship between the output voltage of the characteristic conversion circuit 600 and the output power of the characteristic conversion circuit 600, that is, the output voltage-output power characteristic. The short broken line represents the relationship between the output voltage of the characteristic conversion circuit 600 and the output current of the characteristic conversion circuit 600, that is, the output voltage-output current characteristic. The alternate long and short dash line represents the contribution of the first feedback control. The chain double-dashed line represents the contribution of the second feedback control. The long dashed line represents the first sensor voltage V1.
　図１８から理解されるように、本実施形態では、第１フィードバック制御により、特性変換回路６００の出力電圧－出力電流特性は、出力電流が小さい領域において出力電圧が規定値に追従するものとなる。第２フィードバック制御により、特性変換回路６００の出力電圧－出力電流特性は、出力電流が大きい領域において出力電流が増加するにつれて出力電圧が低下するものとなる。これらのフィードバック制御が相俟って、特性変換回路６００の出力電圧－出力電流特性は、図１８の短破線に示すものとなる。結果として、特性変換回路６００の出力電圧－出力電力特性は、図１８の実線に示すような、単一ピークを有する上に凸のものとなる。 As can be understood from FIG. 18, in the present embodiment, the output voltage-output current characteristic of the characteristic conversion circuit 600 becomes such that the output voltage follows the specified value in the region where the output current is small, by the first feedback control. .. With the second feedback control, the output voltage-output current characteristic of the characteristic conversion circuit 600 is such that the output voltage decreases as the output current increases in the region where the output current is large. Together with these feedback controls, the output voltage-output current characteristic of the characteristic conversion circuit 600 is as shown by the short broken line in FIG. As a result, the output voltage-output power characteristic of the characteristic conversion circuit 600 has a single peak and is convex as shown by the solid line in FIG.
　上述のように、特性変換回路６００の上に凸である出力電圧－出力電力特性は、直流電力変換装置２０によるＭＰＰＴ制御を可能にする。特性変換回路６００のＭＰＰＴ制御は、直流電力変換装置２０によって実行され得る。 As described above, the output voltage-output power characteristic that is convex on the characteristic conversion circuit 600 enables the MPPT control by the DC power conversion device 20. The MPPT control of the characteristic conversion circuit 600 can be executed by the DC power conversion device 20.
　特性変換回路６００の構成について、さらに説明する。 The configuration of the characteristic conversion circuit 600 will be further described.
　図２０に示すように、第１回路６１０は、第１抵抗６２１と、第２抵抗６２２と、第１シャントレギュレータ６２５と、を有する。第２回路６２０は、電流センサ１２８と、センサ電圧調整回路６２０ａと、電圧電流変換回路６２０ｂと、を有する。フィードバック電流供給部１３０は、電流供給電源１３１と、第３抵抗１３２と、を有する。本実施形態では、電流供給電源１３１は、定電圧源である。第３の実施形態の第３抵抗１３２は、第１の実施形態の第７抵抗１３２に対応する。 As shown in FIG. 20, the first circuit 610 has a first resistor 621, a second resistor 622, and a first shunt regulator 625. The second circuit 620 includes a current sensor 128, a sensor voltage adjustment circuit 620a, and a voltage/current conversion circuit 620b. The feedback current supply unit 130 has a current supply power supply 131 and a third resistor 132. In the present embodiment, the current supply power source 131 is a constant voltage source. The third resistor 132 of the third embodiment corresponds to the seventh resistor 132 of the first embodiment.
　電圧電流制御回路１６０は、電流供給電源１３１から流出する電流が小さいほど、電圧電流制御回路１６０の入力電圧に対する出力電圧の比率を大きくする。このように、特性変換回路６００は、電流供給電源１３１から流出する電流に応じて上記比率が調整されるようになっている。 The voltage/current control circuit 160 increases the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 as the current flowing out from the current supply power source 131 is smaller. As described above, in the characteristic conversion circuit 600, the ratio is adjusted according to the current flowing out from the current supply power source 131.
　第１回路６１０では、第１抵抗６２１および第２抵抗６２２により、特性変換回路６００の出力電圧が分圧される。分圧された電圧が、抵抗６２１および抵抗６２２の第１接続点ｐ１に現れる。以下、第１接続点ｐ１に現れる電圧を、第１参照電圧Ｖref1と称することがある。第１参照電圧Ｖref1が、第１シャントレギュレータ６２５の第１参照電圧端子６２５ａに入力される。第１参照電圧端子６２５ａに入力される第１参照電圧Ｖref1が大きいほど、電流供給電源１３１、第３抵抗１３２、第１シャントレギュレータ６２５および基準電位をこの順に流れる電流ｉ１は、大きくなる。図２０において、電流ｉ１は、第１シャントレギュレータ６２５を図示下向きに流れる電流である。以下、電流ｉ１を、第１電流ｉ１と称することがある。 In the first circuit 610, the output voltage of the characteristic conversion circuit 600 is divided by the first resistor 621 and the second resistor 622. The divided voltage appears at the first connection point p1 of the resistors 621 and 622. Hereinafter, the voltage appearing at the first connection point p1 may be referred to as a first reference voltage V ref1 . The first reference voltage V ref1 is input to the first reference voltage terminal 625a of the first shunt regulator 625. The larger the first reference voltage V ref1 input to the first reference voltage terminal 625a, the larger the current i1 flowing through the current supply power supply 131, the third resistor 132, the first shunt regulator 625 and the reference potential in this order. In FIG. 20, the current i1 is a current flowing downward in the first shunt regulator 625. Hereinafter, the current i1 may be referred to as the first current i1.
　本実施形態では、第１フィードバック制御により、特性変換回路６００の開放電圧が制御される。ここで、開放電圧は、特性変換回路６００の出力電流がゼロであるときの特性変換回路６００の出力電圧である。具体的には、第１フィードバック制御において、第１シャントレギュレータ６２５および電圧電流制御回路１６０の働きにより第１参照電圧Ｖref1が後述する第１基準電圧Ｖs1に追従することによって、開放電圧が規定値に設定される。 In the present embodiment, the open circuit voltage of the characteristic conversion circuit 600 is controlled by the first feedback control. Here, the open circuit voltage is the output voltage of the characteristic conversion circuit 600 when the output current of the characteristic conversion circuit 600 is zero. Specifically, in the first feedback control, the operation of the first shunt regulator 625 and the voltage/current control circuit 160 causes the first reference voltage V ref1 to follow a later-described first reference voltage V s1 so that the open circuit voltage is regulated. Set to the value.
　図２１を参照して、本実施形態の第１シャントレギュレータ６２５についてさらに説明する。第１シャントレギュレータ６２５は、第１参照電圧端子６２５ａと、第１カソード６２５Ｋと、第１アノード６２５Ａと、第１基準電圧源６２５ｓと、第１オペアンプ６２５оと、第１トランジスタ６２５ｔと、を含む。第１オペアンプ６２５оは、非反転増幅端子６２５оａと、反転増幅端子６２５оｂと、出力端子６２５оｃと、を含む。第１トランジスタ６２５ｔは、カソード側端子６２５ｔａと、アノード側端子６２５ｔｂと、制御端子６２５ｔｃと、を含む。非反転増幅端子６２５оａには、第１参照電圧端子６２５ａに入力された電圧が供給される。反転増幅端子６２５оｂの電圧は、第１基準電圧源６２５ｓによって、第１アノード６２５Ａの電圧よりも第１基準電圧Ｖs1だけ高い電圧に設定されている。第１参照電圧端子６２５ａに第１基準電圧Ｖs1よりも大きい電圧が入力されることによって非反転増幅端子６２５оａの電圧が反転増幅端子６２５оｂよりも電圧が大きくなると、出力端子６２５оｃから制御端子６２５ｔｃに電流が流れ、第１カソード６２５Ｋからカソード側端子６２５ｔａおよびアノード側端子６２５ｔｂをこの順に介して第１アノード６２５Ａへと第１電流ｉ１が流れる。図２１の例では、第１トランジスタ６２５ｔは、バイポーラトランジスタであり、具体的にはＮＰＮトランジスタである。カソード側端子６２５ｔａは、コレクタである。アノード側端子６２５ｔｂは、エミッタである。制御端子６２５ｔｃは、ベースである。なお、この説明では、出力端子６２５оｃと制御端子６２５ｔｃの間で流れる電流、具体的にはベース電流、は十分に小さいものとして無視している。 The first shunt regulator 625 of this embodiment will be further described with reference to FIG. The first shunt regulator 625 includes a first reference voltage terminal 625a, a first cathode 625K, a first anode 625A, a first reference voltage source 625s, a first operational amplifier 625o, and a first transistor 625t. The first operational amplifier 625о includes a non-inverting amplifier terminal 625оa, an inverting amplifier terminal 625оb, and an output terminal 625оc. The first transistor 625t includes a cathode side terminal 625ta, an anode side terminal 625tb, and a control terminal 625tc. The voltage input to the first reference voltage terminal 625a is supplied to the non-inverting amplification terminal 625a. Voltage of the inverting amplifier terminal 625оb is the first reference voltage source 625S, is set to a high voltage by the first reference voltage V s1 than the voltage of the first anode 625A. When a voltage larger than the first reference voltage V s1 is input to the first reference voltage terminal 625a and the voltage at the non-inverting amplification terminal 625оa becomes larger than the voltage at the inverting amplification terminal 625оb, the output terminal 625оc changes to the control terminal 625tc. A current flows, and the first current i1 flows from the first cathode 625K to the first anode 625A through the cathode side terminal 625ta and the anode side terminal 625tb in this order. In the example of FIG. 21, the first transistor 625t is a bipolar transistor, specifically, an NPN transistor. The cathode side terminal 625ta is a collector. The anode side terminal 625tb is an emitter. The control terminal 625tc is the base. In this description, the current flowing between the output terminal 625c and the control terminal 625tc, specifically the base current, is ignored because it is sufficiently small.
　図２１を参照した説明を踏まえて、第１回路６１０の動作を以下のように説明できる。特性変換回路６００の出力電圧Ｖoutが大きくなると、第１参照電圧Ｖref1は大きくなる。第１シャントレギュレータ６２５では、第１参照電圧Ｖref1が大きくなることにより第１参照電圧Ｖref1の第１基準電圧Ｖs1からの乖離が大きくなればなるほど、第１電流ｉ１が大きくなる。第１電流ｉ１が大きくなると、電流供給電源１３１から流出する電流が大きくなる。この流出電流が大きくなると、電圧電流制御回路１６０の入力電圧に対する出力電圧の比率は小さくなる。このようにして、第１回路６１０は、電圧電流制御回路１６０と協働して、特性変換回路６００の出力電圧Ｖoutを制御する。具体的には、第１回路６１０は、電圧電流制御回路１６０と協働して、第１参照電圧Ｖref1を第１基準電圧Ｖs1に追従させ、特性変換回路６００の出力電圧Ｖoutを規定値に追従させる。 Based on the description with reference to FIG. 21, the operation of the first circuit 610 can be described as follows. As the output voltage V out of the characteristic conversion circuit 600 increases, the first reference voltage V ref1 increases. In the first shunt regulator 625, the greater the deviation from the first reference voltage V s1 of the first reference voltage V ref1 by the first reference voltage V ref1 is increased, the first current i1 increases. As the first current i1 increases, the current flowing out of the current supply power source 131 also increases. When this outflow current increases, the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 decreases. In this way, the first circuit 610 cooperates with the voltage/current control circuit 160 to control the output voltage V out of the characteristic conversion circuit 600. Specifically, the first circuit 610 cooperates with the voltage/current control circuit 160 to cause the first reference voltage V ref1 to follow the first reference voltage V s1 , and defines the output voltage V out of the characteristic conversion circuit 600. Follow the value.
　図２０に戻って、第２回路６２０のセンサ電圧調整回路６２０ａは、可変出力電源１８０と、入力抵抗Ｒ１と、帰還抵抗Ｒ２と、センサ電圧調整オペアンプ１２４と、を含む。 Returning to FIG. 20, the sensor voltage adjustment circuit 620a of the second circuit 620 includes a variable output power supply 180, an input resistor R1, a feedback resistor R2, and a sensor voltage adjustment operational amplifier 124.
　上述のとおり、電流センサ１２８は、第１センサ電圧Ｖ１を出力する。可変出力電源１８０は、可変電圧Ｖ４を出力する。センサ電圧調整回路６２０ａは、第１センサ電圧Ｖ１および可変電圧Ｖ４に応じて変化する第２センサ電圧Ｖ２を生成する。 As described above, the current sensor 128 outputs the first sensor voltage V1. The variable output power supply 180 outputs a variable voltage V4. The sensor voltage adjustment circuit 620a generates a second sensor voltage V2 that changes according to the first sensor voltage V1 and the variable voltage V4.
　電流センサ１２８に個体ばらつきがあると、第１センサ電圧Ｖ１に誤差が生じ得る。誤差を有する第１センサ電圧Ｖ１が特性変換回路６００における制御に用いられると、切替電流ｉswが目標電流からずれ、最大電力点が目標点からずれ、特性変換回路６００の最大電力が目標電力からずれるおそれがある。この点、本実施形態によれば、第１センサ電圧Ｖ１および可変電圧Ｖ４が反映された第２センサ電圧Ｖ２を生成できる。適切に設定された可変電圧Ｖ４が反映された第２センサ電圧Ｖ２を特性変換回路６００における制御に用いることにより、切替電流ｉswの目標電流からのずれを小さくし、最大電力点の目標点からのずれを小さくし、最大電力の目標電力からのずれを小さくすることができる。また、可変電圧Ｖ４を調整して切替電流ｉswを調整することにより、状況に応じて特性変換回路６００の最大電力を調整することも可能である。 If there is individual variation in the current sensor 128, an error may occur in the first sensor voltage V1. When the first sensor voltage V1 having an error is used for control in the characteristic conversion circuit 600, the switching current isw deviates from the target current, the maximum power point deviates from the target point, and the maximum power of the characteristic conversion circuit 600 deviates from the target power. There is a risk of slipping. In this respect, according to the present embodiment, it is possible to generate the second sensor voltage V2 in which the first sensor voltage V1 and the variable voltage V4 are reflected. By using the second sensor voltage V2 in which the appropriately set variable voltage V4 is reflected for the control in the characteristic conversion circuit 600, the deviation of the switching current i sw from the target current is reduced, and the maximum power point is less than the target point. The deviation of the maximum power from the target power can be reduced. Further, it is also possible to adjust the maximum electric power of the characteristic conversion circuit 600 according to the situation by adjusting the variable voltage V4 and the switching current isw .
　具体的には、センサ電圧調整オペアンプ１２４は、センサ入力端子１２４ａと、可変電圧入力端子１２４ｂと、第２センサ電圧出力端子１２４ｃと、を含む。センサ入力端子１２４ａは、入力抵抗Ｒ１を介してセンサ出力部１２８ａに接続されている。可変電圧入力端子１２４ｂには、可変電圧Ｖ４が入力される。第２センサ電圧出力端子１２４ｃは、帰還抵抗Ｒ２を介してセンサ入力端子１２４ａに接続されている。センサ電圧調整オペアンプ１２４は、センサ入力端子１２４ａおよび可変電圧入力端子１２４ｂの電圧差に基づいて第２センサ電圧Ｖ２を生成し、第２センサ電圧出力端子１２４ｃから第２センサ電圧Ｖ２を出力する。 Specifically, the sensor voltage adjustment operational amplifier 124 includes a sensor input terminal 124a, a variable voltage input terminal 124b, and a second sensor voltage output terminal 124c. The sensor input terminal 124a is connected to the sensor output unit 128a via the input resistor R1. The variable voltage V4 is input to the variable voltage input terminal 124b. The second sensor voltage output terminal 124c is connected to the sensor input terminal 124a via the feedback resistor R2. The sensor voltage adjustment operational amplifier 124 generates the second sensor voltage V2 based on the voltage difference between the sensor input terminal 124a and the variable voltage input terminal 124b, and outputs the second sensor voltage V2 from the second sensor voltage output terminal 124c.
　具体的には、センサ入力端子１２４ａは、反転増幅端子である。可変電圧入力端子１２４ｂは、非反転増幅端子である。 Specifically, the sensor input terminal 124a is an inverting amplification terminal. The variable voltage input terminal 124b is a non-inverting amplifier terminal.
　第２回路６２０の電圧電流変換回路６２０ｂは、電圧供給電源１２９と、介在抵抗Ｒ３と、トランジスタ駆動オペアンプ１２６と、調整電流出力トランジスタ１２７と、を含む。電圧供給電源１２９は、閾値電圧Ｖ３を出力する。本実施形態では、電圧供給電源１２９は、定電圧源である。 The voltage/current conversion circuit 620b of the second circuit 620 includes a voltage supply power source 129, an intervening resistor R3, a transistor driving operational amplifier 126, and an adjustment current output transistor 127. The voltage supply power source 129 outputs the threshold voltage V3. In the present embodiment, the voltage supply power source 129 is a constant voltage source.
　電圧電流変換回路６２０ｂでは、第１センサ電圧Ｖ１が大きくなることによって第２センサ電圧Ｖ２が閾値電圧Ｖ３を跨いで変化したときに調整電流ｉ３が流れ始める。調整電流ｉ３が流れ始めたときに、第１フィードバック制御から第２フィードバック制御に切り替わる。電流が流れ始めるタイミングで制御が切り替えられる特性変換回路６００は、設計し易い。 In the voltage-current conversion circuit 620b, when the second sensor voltage V2 changes across the threshold voltage V3 due to the increase in the first sensor voltage V1, the adjusted current i3 starts to flow. When the adjustment current i3 starts to flow, the first feedback control is switched to the second feedback control. The characteristic conversion circuit 600 whose control is switched at the timing when the current starts to flow is easy to design.
　具体的には、トランジスタ駆動オペアンプ１２６は、電源入力端子１２６ａと、第２センサ電圧入力端子１２６ｂと、制御電圧出力端子１２６ｃと、を含む。電源入力端子１２６ａは、介在抵抗Ｒ３を介して電圧供給電源１２９に接続されている。第２センサ電圧入力端子１２６ｂには、第２センサ電圧Ｖ２が入力される。トランジスタ駆動オペアンプ１２６は、電源入力端子１２６ａおよび第２センサ電圧入力端子１２６ｂの電圧差に基づいて制御電圧Ｖcを生成し、制御電圧出力端子１２６ｃから制御電圧Ｖcを出力する。 Specifically, the transistor drive operational amplifier 126 includes a power supply input terminal 126a, a second sensor voltage input terminal 126b, and a control voltage output terminal 126c. The power supply input terminal 126a is connected to the voltage supply power supply 129 via the intervening resistor R3. The second sensor voltage V2 is input to the second sensor voltage input terminal 126b. The transistor drive operational amplifier 126 generates the control voltage V c based on the voltage difference between the power supply input terminal 126 a and the second sensor voltage input terminal 126 b, and outputs the control voltage V c from the control voltage output terminal 126 c .
　具体的には、電源入力端子１２６ａは、反転増幅端子である。第２センサ電圧入力端子１２６ｂは、非反転増幅端子である。 Specifically, the power supply input terminal 126a is an inverting amplification terminal. The second sensor voltage input terminal 126b is a non-inverting amplification terminal.
　調整電流出力トランジスタ１２７は、制御端子１２７ｃと、第１端子１２７ａと、第２端子１２７ｂと、を含む。制御端子１２７ｃには、制御電圧Ｖcが入力される。第１端子１２７ａは、介在抵抗Ｒ３を介して電圧供給電源１２９に接続されている。第２端子１２７ｂは、調整電流ｉ３を出力する。 The adjusted current output transistor 127 includes a control terminal 127c, a first terminal 127a, and a second terminal 127b. The control voltage V c is input to the control terminal 127c. The first terminal 127a is connected to the voltage supply power source 129 via the intervening resistor R3. The second terminal 127b outputs the adjusted current i3.
　図２０の例では、調整電流出力トランジスタ１２７は、バイポーラトランジスタであり、具体的にはＰＮＰトランジスタである。制御端子１２７ｃは、ベースである。第１端子１２７ａは、エミッタである。第２端子１２７ｂは、コレクタである。 In the example of FIG. 20, the adjusted current output transistor 127 is a bipolar transistor, specifically, a PNP transistor. The control terminal 127c is a base. The first terminal 127a is an emitter. The second terminal 127b is a collector.
　第２回路６２０の第１センサ電圧Ｖ１、第２センサ電圧Ｖ２、調整電流ｉ３および出力電圧Ｖoutについて、数式を用いつつさらに説明する。 The first sensor voltage V1, the second sensor voltage V2, the adjustment current i3, and the output voltage Vout of the second circuit 620 will be further described using mathematical expressions.
　図２２に、本実施形態の電流センサ１２８を示す。電流センサ１２８は、シャント抵抗１２８ｒと、電流センスアンプ１２８ｓと、を含む。シャント抵抗１２８ｒの抵抗値は、Ｒsenseである。シャント抵抗１２８ｒに電流Ｉloadが流れると、シャント抵抗１２８ｒに電圧ＲsenseＩloadがかかる。電流センスアンプ１２８ｓは、電圧ＲsenseＩloadにゲインＧを乗じた電圧と、バイアス電圧Ｖbiasと、の合計電圧を、第１センサ電圧Ｖ１として出力する。つまり、本実施形態の電流センサ１２８が生成する第１センサ電圧Ｖ１は、数式４で与えられる。ただし、電流センサ１２８としてホール素子方式の電流センサ等の他の電流センサを用い、その電流センサの出力を第１センサ電圧Ｖ１として用いてもよい。なお、電流Ｉloadは、特性変換回路６００の出力電流に対応する。「＊」は、乗算を表す記号である。図５および図２２から理解されるように、図２２の電流センサ１２８の構成は、図５の電流センサの構成と同様である。
　　数式４：Ｖ１＝Ｒsense＊Ｉload＊Ｇ＋Ｖbias FIG. 22 shows the current sensor 128 of this embodiment. The current sensor 128 includes a shunt resistor 128r and a current sense amplifier 128s. The resistance value of the shunt resistor 128r is R sense . When the current I load flows through the shunt resistor 128r, the voltage R sense I load is applied to the shunt resistor 128r. The current sense amplifier 128s outputs the total voltage of the voltage obtained by multiplying the voltage R sense I load by the gain G and the bias voltage V bias as the first sensor voltage V1. That is, the first sensor voltage V1 generated by the current sensor 128 of the present embodiment is given by Equation 4. However, another current sensor such as a Hall element type current sensor may be used as the current sensor 128, and the output of the current sensor may be used as the first sensor voltage V1. The current I load corresponds to the output current of the characteristic conversion circuit 600. "*" is a symbol representing multiplication. As understood from FIGS. 5 and 22, the configuration of the current sensor 128 of FIG. 22 is similar to the configuration of the current sensor of FIG.
Formula 4: V1=R sense *I load *G+V bias
　センサ電圧調整回路６２０ａでは、センサ電圧調整オペアンプ１２４を用いた差分増幅により、第２センサ電圧Ｖ２が生成される。第２センサ電圧Ｖ２は、以下の数式５で与えられる。ここで、Ｒ１は、入力抵抗Ｒ１の抵抗値である。Ｒ２は、帰還抵抗Ｒ２の抵抗値である。
　　数式５：Ｖ２＝Ｖ４＋（Ｖ４－Ｖ１）＊Ｒ２／Ｒ１ In the sensor voltage adjustment circuit 620a, the second sensor voltage V2 is generated by the differential amplification using the sensor voltage adjustment operational amplifier 124. The second sensor voltage V2 is given by Equation 5 below. Here, R1 is the resistance value of the input resistor R1. R2 is the resistance value of the feedback resistor R2.
Formula 5: V2=V4+(V4-V1)*R2/R1
　電圧電流変換回路６２０ｂでは、トランジスタ駆動オペアンプ１２６は、Ｖ２＜Ｖ３のときには、バーチャルショートにより電源入力端子１２６ａの電圧が第２センサ電圧入力端子１２６ｂの電圧に追従するように、調整電流出力トランジスタ１２７を駆動させる。具体的には、トランジスタ駆動オペアンプ１２６は、Ｖ２＜Ｖ３のときには、電源入力端子１２６ａの電圧が第２センサ電圧Ｖ２となり、閾値電圧Ｖ３と第２センサ電圧Ｖ２との電圧差Ｖ３－Ｖ２が介在抵抗Ｒ３にかかり、かつ、介在抵抗Ｒ３から第１端子１２７ａへと電流（Ｖ３－Ｖ２）／Ｒ３が流れるように、制御端子１２７ｃを駆動する。より具体的には、この駆動時に、制御電圧出力端子１２６ｃと制御端子１２７ｃの間で電流が流れる。ここで、Ｒ３は、介在抵抗Ｒ３の抵抗値である。Ｖ２＜Ｖ３のときには、調整電流ｉ３は、以下の数式６で与えられる。Ｖ２≧Ｖ３のときには、調整電流ｉ３は、以下の数式７で与えられる。なお、数式６では、制御電圧出力端子１２６ｃと制御端子１２７ｃの間で流れる電流、図２０の例ではベース電流、は十分に小さいものとして無視している。
　　数式６：ｉ３＝（Ｖ３－Ｖ２）／Ｒ３
　　数式７：ｉ３＝０ In the voltage-current conversion circuit 620b, the transistor driving operational amplifier 126 sets the adjusted current output transistor 127 so that the voltage of the power supply input terminal 126a follows the voltage of the second sensor voltage input terminal 126b due to a virtual short when V2<V3. Drive it. Specifically, in the transistor drive operational amplifier 126, when V2<V3, the voltage of the power supply input terminal 126a becomes the second sensor voltage V2, and the voltage difference V3-V2 between the threshold voltage V3 and the second sensor voltage V2 causes the intervening resistance. The control terminal 127c is driven so that the current (V3-V2)/R3 is applied to R3 and flows from the intervening resistor R3 to the first terminal 127a. More specifically, during this driving, a current flows between the control voltage output terminal 126c and the control terminal 127c. Here, R3 is the resistance value of the intervening resistor R3. When V2<V3, the adjusted current i3 is given by the following formula 6. When V2≧V3, the adjustment current i3 is given by the following formula 7. In Equation 6, the current flowing between the control voltage output terminal 126c and the control terminal 127c, the base current in the example of FIG. 20, is neglected because it is sufficiently small.
Formula 6: i3=(V3-V2)/R3
Formula 7: i3=0
　図示の例では、トランジスタ駆動オペアンプ１２６は、調整電流出力トランジスタ１２７の端子１２７ｃ－１２７ａ間電圧の温度による変化により調整電流ｉ３が変化することを抑制している。具体的には、仮に、トランジスタ１２７の制御端子１２７ｃに第２センサ電圧Ｖ２が直接供給されると、第１端子１２７ａの電圧は、第２センサ電圧Ｖ２に端子１２７ｃ－１２７ａ間電圧を足し合わせた値となるため、端子１２７ｃ－１２７ａ間電圧の影響を受けることになる。これに対し、本実施形態では、オペアンプ１２６の端子１２６ａおよび１２６ｂがバーチャルショートしているため、第１端子１２７ａの電圧と第２センサ電圧Ｖ２とは実質的に同一となり、調整電流ｉ３は端子１２７ｃ－１２７ａ間電圧の影響を実質的に受けなくなる。先に述べた通り、具体的には、制御端子１２７ｃは、ベースである。第１端子１２７ａは、エミッタである。第２端子１２７ｂは、コレクタである。端子１２７ｃ－１２７ａ間電圧は、ベース－エミッタ間電圧である。 In the illustrated example, the transistor drive operational amplifier 126 suppresses the change of the adjustment current i3 due to the change of the voltage between the terminals 127c-127a of the adjustment current output transistor 127 with temperature. Specifically, if the second sensor voltage V2 is directly supplied to the control terminal 127c of the transistor 127, the voltage of the first terminal 127a is the sum of the second sensor voltage V2 and the voltage between the terminals 127c-127a. Since the value becomes a value, it is affected by the voltage between the terminals 127c-127a. On the other hand, in the present embodiment, since the terminals 126a and 126b of the operational amplifier 126 are virtually short-circuited, the voltage of the first terminal 127a and the second sensor voltage V2 are substantially the same, and the adjustment current i3 is the terminal 127c. It is virtually unaffected by the voltage between -127a. As described above, specifically, the control terminal 127c is the base. The first terminal 127a is an emitter. The second terminal 127b is a collector. The voltage between the terminals 127c-127a is the voltage between the base and the emitter.
　図２１を用いた上述の説明から理解されるように、第１シャントレギュレータ６２５により、第１参照電圧Ｖref1は、一定の第１基準電圧Ｖs1に追従する。出力電圧Ｖoutは、以下の数式８で与えられる。ここで、Ｒ６２１は、第１抵抗６２１の抵抗値である。Ｒ６２２は、第２抵抗６２２の抵抗値である。数式８は、調整電流ｉ３が大きくなるほど特性変換回路６００の出力電圧Ｖoutが小さくなることを示している。
　　数式８：Ｖout＝（Ｖref1／Ｒ６２２－ｉ３）＊Ｒ６２１＋Ｖref1 As will be understood from the above description using FIG. 21, the first shunt regulator 625 causes the first reference voltage V ref1 to follow the constant first reference voltage V s1 . The output voltage V out is given by Equation 8 below. Here, R621 is the resistance value of the first resistor 621. R622 is the resistance value of the second resistor 622. Formula 8 indicates that the output voltage V out of the characteristic conversion circuit 600 decreases as the adjustment current i3 increases.
Formula 8: V out =(V ref1 /R622-i3)*R621+V ref1
　数式８および図１９から理解されるように、調整電流ｉ３が流れると、出力電圧Ｖoutは小さくなる。このように、調整電流ｉ３は、出力電圧Ｖoutを調整するように作用する。調整電流ｉ３を、出力電圧調整電流ｉ３と称することができる。 As can be understood from Expression 8 and FIG. 19, when the adjustment current i3 flows, the output voltage V out decreases. In this way, the adjustment current i3 acts to adjust the output voltage V out . The adjustment current i3 can be referred to as the output voltage adjustment current i3.
　以上の説明から理解されるように、本実施形態では、第２フィードバック制御は、第１フィードバック制御を調整することによって実現される。具体的には、第２回路６２０によってこの調整が行われる。第２回路６２０を、調整回路と称することができる。 As can be understood from the above description, in the present embodiment, the second feedback control is realized by adjusting the first feedback control. Specifically, this adjustment is performed by the second circuit 620. The second circuit 620 can be referred to as an adjustment circuit.
　本実施形態では、燃料電池発電システム４０の出力特性の変換を、第１回路６１０および第２回路６２０を用いて行う。ソフトウエアが担い得る役割を回路で担うことは、制御構成の簡易化、コスト等の観点から有利であることが多い。また、このことにより、ソフトウエアの設計を回避でき、ソフトウエアでバグが生じるリスクを回避できる。 In the present embodiment, the conversion of the output characteristics of the fuel cell power generation system 40 is performed using the first circuit 610 and the second circuit 620. It is often advantageous from the viewpoint of simplification of control configuration, cost, etc. that the circuit plays a role that software can play. Further, this makes it possible to avoid the software design and avoid the risk of software bugs.
　また、回路を用いて特性変換を行う方式は、燃料電池発電システムと相性がよい。具体的には、燃料電池発電システムの出力電圧および出力電力は、風力発電システム等とは異なり、一定に維持し易い。一具体例では、燃料電池発電システムの出力電圧および出力電力は、定格発電において一定に維持される。このため、特性変換回路に接続される発電システムが燃料電池発電システムである場合、特性変換の特性を発電システムの出力電圧および／または出力電力に応じて変更する必要性が低く、回路を用いて特性変換を行う方式を採用し易い。 Also, the method of converting characteristics using a circuit is compatible with the fuel cell power generation system. Specifically, the output voltage and the output power of the fuel cell power generation system are easy to maintain constant unlike the wind power generation system and the like. In one embodiment, the output voltage and output power of the fuel cell power generation system are maintained constant at rated power generation. Therefore, when the power generation system connected to the characteristic conversion circuit is a fuel cell power generation system, it is not necessary to change the characteristic conversion characteristics according to the output voltage and/or the output power of the power generation system, and the circuit is used. It is easy to adopt a method that performs characteristic conversion.
［電流センサ１２８の個体ばらつきとその抑制］
　上述のとおり、電流センサ１２８には、個体ばらつきがあることがある。図２３および図２４を参照しつつ、個体ばらつきの影響について、詳細に説明する。 [Individual variation of current sensor 128 and its suppression]
As described above, the current sensor 128 may have individual variations. The influence of individual variation will be described in detail with reference to FIGS. 23 and 24.
　本実施形態では、電流センサ１２８は、図２２に示した構成を有する。シャント抵抗１２８ｒの抵抗値Ｒsense、ゲインＧおよびバイアス電圧Ｖbiasは、理想的には基準値である。しかし、抵抗値Ｒsense、ゲインＧおよび／またはバイアス電圧Ｖbiasには、公差の範囲の誤差があり得る。本実施形態では、電流センサ１２８は、シャント抵抗１２８ｒの抵抗値が基準値よりも大きいときには、シャント抵抗１２８ｒの抵抗値が基準値であるときに比べ、大きい第１センサ電圧Ｖ１を出力するように構成されている。電流センサ１２８は、ゲインＧが基準値よりも大きいときには、ゲインＧが基準値であるときに比べ、大きい第１センサ電圧Ｖ１を出力するように構成されている。電流センサ１２８は、バイアス電圧Ｖbiasが基準値よりも大きいときには、バイアス電圧Ｖbiasが基準値であるときに比べ、大きい第１センサ電圧Ｖ１を出力するように構成されている。 In the present embodiment, the current sensor 128 has the configuration shown in FIG. The resistance value R sense of the shunt resistor 128r, the gain G, and the bias voltage V bias are ideally reference values. However, the resistance value R sense , the gain G, and/or the bias voltage V bias may have an error in the tolerance range. In the present embodiment, the current sensor 128 outputs a larger first sensor voltage V1 when the resistance value of the shunt resistor 128r is larger than the reference value, compared to when the resistance value of the shunt resistor 128r is the reference value. It is configured. The current sensor 128 is configured to output a larger first sensor voltage V1 when the gain G is larger than the reference value, compared to when the gain G is the reference value. Current sensor 128, when the bias voltage V bias is larger than the reference value, than when the bias voltage V bias is the reference value, and is configured to output a large first sensor voltage V1.
　図２３において、横軸は、特性変換回路６００の出力電圧を示す。図２３では、ゲインＧおよびバイアス電圧Ｖbiasが基準値にある場合において、抵抗値Ｒsenseを変化させた場合の特性変換回路６００の出力特性を示す。 In FIG. 23, the horizontal axis represents the output voltage of the characteristic conversion circuit 600. FIG. 23 shows the output characteristic of the characteristic conversion circuit 600 when the resistance value R sense is changed when the gain G and the bias voltage V bias are at the reference values.
　具体的には、図２３において、「特性変換回路の出力電流（０）」は、シャント抵抗１２８ｒの抵抗値Ｒsenseが基準値にあるときの、特性変換回路６００の出力電流を示す。「特性変換回路の出力電流（＋）」は、抵抗値Ｒsenseが基準値よりも大きいときの、同出力電流を示す。「特性変換回路の出力電流（－）」は、抵抗値Ｒsenseが基準値よりも小さいときの、同出力電流を示す。「特性変換回路の出力電力（０）」は、抵抗値Ｒsenseが基準値にあるときの、特性変換回路６００の出力電力を示す。「特性変換回路の出力電力（＋）」は、抵抗値Ｒsenseが基準値よりも大きいときの、同出力電力を示す。「特性変換回路の出力電力（－）」は、抵抗値Ｒsenseが基準値よりも小さいときの、同出力電力を示す。 Specifically, in FIG. 23, “output current (0) of characteristic conversion circuit” indicates the output current of the characteristic conversion circuit 600 when the resistance value R sense of the shunt resistor 128r is at the reference value. The “output current (+) of the characteristic conversion circuit” indicates the same output current when the resistance value R sense is larger than the reference value. “Output current (−) of characteristic conversion circuit” indicates the same output current when the resistance value R sense is smaller than the reference value. “Output power of characteristic conversion circuit (0)” indicates output power of the characteristic conversion circuit 600 when the resistance value R sense is at the reference value. The “output power (+) of the characteristic conversion circuit” indicates the same output power when the resistance value R sense is larger than the reference value. “Output power (−) of characteristic conversion circuit” indicates the same output power when the resistance value R sense is smaller than the reference value.
　図２４において、横軸は、特性変換回路６００の出力電流を示す。図２４では、ゲインＧおよびバイアス電圧Ｖbiasが基準値にある場合において、抵抗値Ｒsenseを変化させた場合の特性変換回路６００の出力特性を示す。 In FIG. 24, the horizontal axis represents the output current of the characteristic conversion circuit 600. FIG. 24 shows the output characteristics of the characteristic conversion circuit 600 when the resistance value R sense is changed when the gain G and the bias voltage V bias are at the reference values.
　具体的には、図２４において、「特性変換回路の出力電圧（０）」は、シャント抵抗１２８ｒの抵抗値Ｒsenseが基準値にあるときの、特性変換回路６００の出力電圧を示す。「特性変換回路の出力電圧（＋）」は、抵抗値Ｒsenseが基準値よりも大きいときの、同出力電圧を示す。「特性変換回路の出力電圧（－）」は、抵抗値Ｒsenseが基準値よりも小さいときの、同出力電圧を示す。「調整電流ｉ３（０）」は、シャント抵抗１２８ｒの抵抗値Ｒsenseが基準値にあるときの、調整電流ｉ３を示す。「調整電流ｉ３（＋）」は、抵抗値Ｒsenseが基準値よりも大きいときの、調整電流ｉ３を示す。「調整電流ｉ３（－）」は、抵抗値Ｒsenseが基準値よりも小さいときの、調整電流ｉ３を示す。「特性変換回路の出力電力（０）」は、抵抗値Ｒsenseが基準値にあるときの、特性変換回路６００の出力電力を示す。「特性変換回路の出力電力（＋）」は、抵抗値Ｒsenseが基準値よりも大きいときの、同出力電力を示す。「特性変換回路の出力電力（－）」は、抵抗値Ｒsenseが基準値よりも小さいときの、同出力電力を示す。「切替電流ｉsw（０）」は、抵抗値Ｒsenseが基準値にあるときの、切替電流ｉswを示す。「切替電流ｉsw（＋）」は、抵抗値Ｒsenseが基準値よりも大きいときの、切替電流ｉswを示す。「切替電流ｉsw（－）」は、抵抗値Ｒsenseが基準値よりも小さいときの、切替電流ｉswを示す。上述のとおり、切替電流ｉswは、第１フィードバック制御と第２フィードバック制御とが切り替わるときの特性変換回路６００の出力電流である。 Specifically, in FIG. 24, “output voltage (0) of characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 600 when the resistance value R sense of the shunt resistor 128r is at the reference value. The “output voltage (+) of the characteristic conversion circuit” indicates the same output voltage when the resistance value R sense is larger than the reference value. “Output voltage (−) of characteristic conversion circuit” indicates the same output voltage when the resistance value R sense is smaller than the reference value. “Adjustment current i3(0)” indicates the adjustment current i3 when the resistance value R sense of the shunt resistor 128r is at the reference value. “Adjustment current i3(+)” indicates the adjustment current i3 when the resistance value R sense is larger than the reference value. “Adjustment current i3(−)” indicates the adjustment current i3 when the resistance value R sense is smaller than the reference value. “Output power of characteristic conversion circuit (0)” indicates output power of the characteristic conversion circuit 600 when the resistance value R sense is at the reference value. The “output power (+) of the characteristic conversion circuit” indicates the same output power when the resistance value R sense is larger than the reference value. “Output power (−) of characteristic conversion circuit” indicates the same output power when the resistance value R sense is smaller than the reference value. "Switching current i sw (0)" indicates the switching current i sw when the resistance value R sense is at the reference value. "Switching current i sw (+)" indicates the switching current i sw when the resistance value R sense is larger than the reference value. “Switching current i sw (−)” indicates the switching current i sw when the resistance value R sense is smaller than the reference value. As described above, the switching current isw is the output current of the characteristic conversion circuit 600 when the first feedback control and the second feedback control are switched.
　抵抗値Ｒsenseが基準値であるとき、最大電力点は、目標点にある。この状況は、図１８および図１９に示したとおりである。 When the resistance value R sense is the reference value, the maximum power point is at the target point. This situation is as shown in FIGS. 18 and 19.
　抵抗値Ｒsenseが基準値にあるとき、切替電流ｉswは、目標電流に一致する。「切替電流ｉsw（０）」が、目標電流に対応する。抵抗値Ｒsenseが基準値よりも大きいと、抵抗値Ｒsenseが基準値にあるときに比べ、切替電流ｉswは小さい。反対に、抵抗値Ｒsenseが基準値よりも小さいと、抵抗値Ｒsenseが基準値にあるときに比べ、切替電流ｉswは大きい。 When the resistance value R sense is at the reference value, the switching current isw matches the target current. "Switching current isw (0)" corresponds to the target current. When the resistance value R sense is larger than the reference value, the switching current isw is smaller than when the resistance value R sense is at the reference value. On the contrary, when the resistance value R sense is smaller than the reference value, the switching current i sw is larger than when the resistance value R sense is at the reference value.
　抵抗値Ｒsenseが基準値にあるとき、特性変換回路６００の最大電力は、目標電力に一致する。特性変換回路６００の出力電流が「切替電流ｉsw（０）」であるときの「特性変換回路の出力電力（０）」が、目標電力に対応する。抵抗値Ｒsenseが基準値よりも大きいと、抵抗値Ｒsenseが基準値にあるときに比べ、最大電力は小さい。反対に、抵抗値Ｒsenseが基準値よりも小さいと、抵抗値Ｒsenseが基準値にあるときに比べ、最大電力は大きい。 When the resistance value R sense is at the reference value, the maximum power of the characteristic conversion circuit 600 matches the target power. The “output power (0) of the characteristic conversion circuit” when the output current of the characteristic conversion circuit 600 is the “switching current i sw (0)” corresponds to the target power. When the resistance value R sense is larger than the reference value, the maximum power is smaller than when the resistance value R sense is at the reference value. On the contrary, when the resistance value R sense is smaller than the reference value, the maximum power is larger than when the resistance value R sense is at the reference value.
　図２３および図２４に示されているように、シャント抵抗１２８ｒの抵抗値Ｒsenseの個体ばらつきは、特性変換回路６００の最大電力点のばらつきをもたらす。最大電力点のばらつきは、切替電流ｉswおよび最大電力のばらつきをもたらす。 As shown in FIGS. 23 and 24, the individual variation of the resistance value R sense of the shunt resistor 128r causes the variation of the maximum power point of the characteristic conversion circuit 600. The variation of the maximum power point causes the variation of the switching current isw and the maximum power.
　この点、本実施形態では、可変電圧Ｖ４を調整することにより、特性変換回路６００の切替電流ｉswを調整し、最大電力を調整することができる。 In this respect, in the present embodiment, by adjusting the variable voltage V4, the switching current isw of the characteristic conversion circuit 600 can be adjusted and the maximum power can be adjusted.
　例えば、抵抗値Ｒsenseが基準値よりも小さく、抵抗値Ｒsenseが基準値にあるときに比べ、切替電流ｉswおよび最大電力が大きい場合を考える。この場合、抵抗値Ｒsenseが基準値にある場合に比べて可変電圧Ｖ４を小さくすることにより、切替電流ｉswおよび最大電力を小さくすることができる。これにより、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。 For example, consider a case where the resistance value R sense is smaller than the reference value and the switching current isw and maximum power are larger than when the resistance value R sense is at the reference value. In this case, the switching current isw and the maximum power can be reduced by reducing the variable voltage V4 as compared with the case where the resistance value R sense is at the reference value. As a result, the switching current isw and the maximum power can be brought close to the target current and the target power.
　反対に、抵抗値Ｒsenseが基準値よりも大きく、抵抗値Ｒsenseが基準値にあるときに比べ、切替電流ｉswおよび最大電力が小さい場合を考える。この場合、抵抗値Ｒsenseが基準値にある場合に比べて可変電圧Ｖ４を大きくすることにより、切替電流ｉswおよび最大電力を大きくすることができる。これにより、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。 On the contrary, consider a case where the resistance value R sense is larger than the reference value and the switching current isw and the maximum power are smaller than when the resistance value R sense is at the reference value. In this case, the switching current i sw and the maximum power can be increased by increasing the variable voltage V4 as compared with the case where the resistance value R sense is at the reference value. As a result, the switching current isw and the maximum power can be brought close to the target current and the target power.
　可変電圧Ｖ４の調整が、調整電流ｉ３および最大電力を変化させ得ることについて、図２５を参照しながらさらに説明する。 It will be further described with reference to FIG. 25 that the adjustment of the variable voltage V4 can change the adjustment current i3 and the maximum power.
　図２５の（ａ）に、第１センサ電圧Ｖ１を示す。ただし、この第１センサ電圧Ｖ１には、電流センサ１２８の個体ばらつきに由来する誤差がある可能性がある。 25(a) shows the first sensor voltage V1. However, the first sensor voltage V1 may have an error due to individual variations of the current sensor 128.
　図２５の（ｂ）に、第２センサ電圧Ｖ２を示す。電圧Ｖ２ａは、可変電圧Ｖ４を調整する前の第２センサ電圧Ｖ２である。なお、調整前の可変電圧Ｖ４は、０Ｖであってもなくてもよい。数式５から理解されるように、可変電圧Ｖ４を大きくすると、第２センサ電圧Ｖ２は大きくなる。電圧Ｖ２ｂは、このようにして大きくなった後の第２センサ電圧Ｖ２である。反対に、可変電圧Ｖ４を小さくすると、第２センサ電圧Ｖ２は小さくなる。電圧Ｖ２ｃは、このようにして小さくなった後の第２センサ電圧Ｖ２である。矢印ＡＲ１は、可変電圧Ｖ４を調整することにより、第２センサ電圧Ｖ２を調整できることを示している。 The second sensor voltage V2 is shown in FIG. The voltage V2a is the second sensor voltage V2 before adjusting the variable voltage V4. The variable voltage V4 before adjustment may or may not be 0V. As can be understood from Expression 5, when the variable voltage V4 is increased, the second sensor voltage V2 is increased. The voltage V2b is the second sensor voltage V2 after being increased in this way. On the contrary, when the variable voltage V4 is reduced, the second sensor voltage V2 is reduced. The voltage V2c is the second sensor voltage V2 after being reduced in this way. The arrow AR1 indicates that the second sensor voltage V2 can be adjusted by adjusting the variable voltage V4.
　図２５の（ｃ）に、調整電流ｉ３および切替電流ｉswを示す。電流ｉ３ａは、可変電圧Ｖ４および第２センサ電圧Ｖ２を調整する前の調整電流ｉ３である。電流ｉswａは、このときの切替電流ｉswである。第２センサ電圧Ｖ２を大きくして電圧Ｖ２ｂにすると、特性変換回路６００の出力電流がより大きいときに調整電流ｉ３が流れ始めるようになる。電流ｉ３ｂは、このようにして流れ始めるタイミングが変化した後の調整電流ｉ３である。電流ｉswｂは、このときの切替電流ｉswである。反対に、第２センサ電圧Ｖ２を小さくして電圧Ｖ２ｃにすると、特性変換回路６００の出力電流がより小さいときに調整電流ｉ３が流れ始めるようになる。電流ｉ３ｃは、このようにして流れ始めるタイミングが変化した後の調整電流ｉ３である。電流ｉswｃは、このときの切替電流ｉswである。矢印ＡＲ２は、可変電圧Ｖ４を調整して第２センサ電圧Ｖ２を調整することにより、切替電流ｉswを調整できることを示している。この調整により、最大電力が調整される。 FIG. 25C shows the adjustment current i3 and the switching current isw . The current i3a is the adjusted current i3 before adjusting the variable voltage V4 and the second sensor voltage V2. The current i sw a is the switching current i sw at this time. When the second sensor voltage V2 is increased to the voltage V2b, the adjusted current i3 starts to flow when the output current of the characteristic conversion circuit 600 is larger. The current i3b is the adjusted current i3 after the timing at which the current starts to change in this way. The current i sw b is the switching current i sw at this time. On the contrary, when the second sensor voltage V2 is reduced to the voltage V2c, the adjusted current i3 starts to flow when the output current of the characteristic conversion circuit 600 is smaller. The current i3c is the adjusted current i3 after the timing at which the current starts to change in this way. The current i sw c is the switching current i sw at this time. The arrow AR2 indicates that the switching current isw can be adjusted by adjusting the variable voltage V4 and the second sensor voltage V2. By this adjustment, the maximum power is adjusted.
　可変電圧Ｖ４の調整により、切替電流ｉswおよび最大電力を、抵抗値Ｒsenseが基準値にあるときの値に近づけることができる。つまり、切替電流ｉswおよび最大電力を、目標電流および目標電力に近づけることができる。 By adjusting the variable voltage V4, the switching current isw and the maximum power can be brought close to the values when the resistance value R sense is at the reference value. That is, the switching current isw and the maximum power can be brought close to the target current and the target power.
　電流センサ１２８が図２２に示す構成を有する場合、バイアス電圧Ｖbiasの個体ばらつきもまた、特性変換回路６００の最大電力点のばらつきをもたらし得る。ゲインＧの個体ばらつきもまた、特性変換回路６００の最大電力点のばらつきをもたらし得る。電流センサ１２８がホール素子方式の電流センサ等の他のセンサである場合も、電流センサ１２８の個体ばらつきに由来する誤差が、特性変換回路６００の最大電力点のばらつきをもたらし得る。しかし、これらの場合も、シャント抵抗１２８ｒの抵抗値Ｒsenseにばらつきがある場合と同様、可変電圧Ｖ４の調整により、特性変換回路６００の最大電力点を目標点に近づけ、切替電流ｉswおよび最大電力を目標電流および目標電力に近づけることができる。 When the current sensor 128 has the configuration shown in FIG. 22, individual variations in the bias voltage V bias can also cause variations in the maximum power point of the characteristic conversion circuit 600. Individual variations in the gain G can also cause variations in the maximum power point of the characteristic conversion circuit 600. Even when the current sensor 128 is another sensor such as a Hall element type current sensor, an error resulting from individual variation of the current sensor 128 may cause variation in the maximum power point of the characteristic conversion circuit 600. However, in these cases as well, as in the case where the resistance value R sense of the shunt resistor 128r varies, the maximum power point of the characteristic conversion circuit 600 is brought close to the target point by adjusting the variable voltage V4, and the switching current i sw and the maximum value. The power can be brought close to the target current and the target power.
［可変電圧Ｖ４の調整の仕方の例］
　以下、可変電圧Ｖ４の第１調整例および第２調整例について説明する。 [Example of how to adjust the variable voltage V4]
Hereinafter, a first adjustment example and a second adjustment example of the variable voltage V4 will be described.
　切替電流ｉswの目標値すなわち目標電流がある場合を考える。第１調整例および第２調整例では、出力電流が目標電流であるときに出力電圧が目標電圧となり出力電力が最大電力かつ目標電力となるように、可変電圧Ｖ４を調整して特性変換回路６００を校正する。具体的に、第１調整例および第２調整例では、目標電流は、図２４の「切替電流ｉsw（０）」である。目標電圧は、図２４における出力電流が「切替電流ｉsw（０）」であるときの「特性変換回路の出力電圧（０）」である。最大電力および目標電力は、図２４における出力電流が「切替電流ｉsw（０）」であるときの「特性変換回路の出力電力（０）」である。 Consider a case where there is a target value of the switching current isw , that is, a target current. In the first adjustment example and the second adjustment example, the variable voltage V4 is adjusted so that the output voltage becomes the target voltage and the output power becomes the maximum power and the target power when the output current is the target current. Calibrate. Specifically, in the first adjustment example and the second adjustment example, the target current is the “switching current isw (0)” in FIG. The target voltage is the “output voltage (0) of the characteristic conversion circuit” when the output current in FIG. 24 is the “switching current i sw (0)”. The maximum power and the target power are the “output power (0) of the characteristic conversion circuit” when the output current in FIG. 24 is the “switching current i sw (0)”.
　第１調整例では、可変電圧Ｖ４は、以下のように調整される。まず、特性変換回路６００の出力電流が目標電流に固定されるよう第１ＤＣＤＣコンバータ２１に定電流制御を行わせつつ、燃料電池発電システム４０から特性変換回路６００に直流電力を供給する。次に、特性変換回路６００の出力電圧が目標電圧となるように可変電圧Ｖ４を調整する。 In the first adjustment example, the variable voltage V4 is adjusted as follows. First, direct current power is supplied from the fuel cell power generation system 40 to the characteristic conversion circuit 600 while causing the first DCDC converter 21 to perform constant current control so that the output current of the characteristic conversion circuit 600 is fixed to the target current. Next, the variable voltage V4 is adjusted so that the output voltage of the characteristic conversion circuit 600 becomes the target voltage.
　具体的に、第１調整例において、特性変換回路６００が、図２４の「特性変換回路の出力電圧（＋）」に示す出力電流－出力電圧特性を有するとする。その場合、出力電流が「切替電流ｉsw（０）」のときは、出力電圧は目標電圧よりも低い。そこで、可変電圧Ｖ４を大きくする。そうすると、出力電流－出力電圧特性が変化して、出力電圧が目標電圧に近づく。可変電圧Ｖ４を適度に大きくすることで、出力電圧を目標電圧に一致させることができる。さらに、この可変電圧Ｖ４の設定により、切替電流ｉswは目標電流に一致し、出力電力は最大電力かつ目標電力となる。これにより、上記校正が実現される。 Specifically, in the first adjustment example, it is assumed that the characteristic conversion circuit 600 has an output current-output voltage characteristic shown in “output voltage (+) of characteristic conversion circuit” of FIG. In that case, when the output current is the "switching current isw (0)", the output voltage is lower than the target voltage. Therefore, the variable voltage V4 is increased. Then, the output current-output voltage characteristic changes, and the output voltage approaches the target voltage. By appropriately increasing the variable voltage V4, the output voltage can be matched with the target voltage. Further, by setting the variable voltage V4, the switching current i sw matches the target current, and the output power becomes the maximum power and the target power. Thereby, the above calibration is realized.
　また、第１調整例において、特性変換回路６００が、図２４の「特性変換回路の出力電圧（－）」に示す出力電流－出力電圧特性を有するとする。その場合、出力電流が「切替電流ｉsw（０）」のときは、出力電圧は目標電圧と同じである。ここで、可変電圧Ｖ４を小さくする。可変電圧Ｖ４の低下幅がある程度に達したときに、出力電圧が目標電圧から下がり始める。出力電圧が下がり始めるときの値に可変電圧Ｖ４を設定することで、出力電圧を目標電圧に一致させつつ、切替電流ｉswを目標電流に一致させ、出力電力を最大電力かつ目標電力にできる。これにより、上記校正が実現される。 Further, in the first adjustment example, it is assumed that the characteristic conversion circuit 600 has an output current-output voltage characteristic shown in “output voltage (−) of characteristic conversion circuit” of FIG. In that case, when the output current is the “switching current isw (0)”, the output voltage is the same as the target voltage. Here, the variable voltage V4 is reduced. When the decrease width of the variable voltage V4 reaches a certain level, the output voltage starts to decrease from the target voltage. By setting the variable voltage V4 to the value at which the output voltage starts to drop, the output current can be made the maximum power and the target power while making the output voltage match the target voltage and the switching current isw match the target current. Thereby, the above calibration is realized.
　第２調整例では、可変電圧Ｖ４は、以下のように調整される。まず、特性変換回路６００の出力電流が目標電流に固定されるよう第１ＤＣＤＣコンバータ２１に定電流制御を行わせつつ、燃料電池発電システム４０から特性変換回路６００に直流電力を供給する。次に、特性変換回路６００の出力電力が目標電力となるように可変電圧Ｖ４を調整する。なお、特性変換回路６００の出力電力は、パワーメータ等を用いて測定できる。 In the second adjustment example, the variable voltage V4 is adjusted as follows. First, direct current power is supplied from the fuel cell power generation system 40 to the characteristic conversion circuit 600 while causing the first DCDC converter 21 to perform constant current control so that the output current of the characteristic conversion circuit 600 is fixed to the target current. Next, the variable voltage V4 is adjusted so that the output power of the characteristic conversion circuit 600 becomes the target power. The output power of the characteristic conversion circuit 600 can be measured using a power meter or the like.
　具体的に、第２調整例において、特性変換回路６００が、図２４の「特性変換回路の出力電力（＋）」に示す出力電流－出力電力特性を有するとする。その場合、出力電流が「切替電流ｉsw（０）」のときは、出力電力は目標電力よりも低い。そこで、可変電圧Ｖ４を大きくする。そうすると、出力電流－出力電力特性が変化して、出力電力が目標電力に近づく。可変電圧Ｖ４を適度に大きくすることで、出力電力を最大電力かつ目標電力にすることができる。さらに、この可変電圧Ｖ４の設定により、切替電流ｉswは目標電流に一致し、出力電圧は目標電圧に一致する。これにより、上記校正が実現される。 Specifically, in the second adjustment example, it is assumed that the characteristic conversion circuit 600 has the output current-output power characteristic shown in “output power (+) of characteristic conversion circuit” in FIG. In that case, the output power is lower than the target power when the output current is the “switching current isw (0)”. Therefore, the variable voltage V4 is increased. Then, the output current-output power characteristic changes, and the output power approaches the target power. By appropriately increasing the variable voltage V4, the output power can be the maximum power and the target power. Further, by setting the variable voltage V4, the switching current isw matches the target current, and the output voltage matches the target voltage. Thereby, the above calibration is realized.
　また、第２調整例において、特性変換回路６００が、図２４の「特性変換回路の出力電力（－）」に示す出力電流－出力電力特性を有するとする。その場合、出力電流が「切替電流ｉsw（０）」のときは、出力電力は、最大電力ではないが、目標電力と同じである。ここで、可変電圧Ｖ４を小さくする。可変電圧Ｖ４の低下幅がある程度に達したときに、出力電力が目標電力から下がり始める。出力電力が下がり始めるときの値に可変電圧Ｖ４を設定することで、出力電力を最大電力かつ目標電力にしつつ、切替電流ｉswを目標電流に一致させ、出力電圧を目標電圧に一致させることができる。これにより、上記校正が実現される。 Further, in the second adjustment example, it is assumed that the characteristic conversion circuit 600 has an output current-output power characteristic shown in “output power (−) of characteristic conversion circuit” of FIG. In that case, when the output current is the “switching current i sw (0)”, the output power is not the maximum power but is the same as the target power. Here, the variable voltage V4 is reduced. When the decrease width of the variable voltage V4 reaches a certain level, the output power starts to decrease from the target power. By setting the variable voltage V4 to the value at which the output power starts to decrease, the switching current isw can be made to match the target current and the output voltage can be made to match the target voltage while making the output power the maximum power and the target power. it can. Thereby, the above calibration is realized.
［状況に応じた特性変換回路６００の最大電力の調整］
　可変パラメータの調整により、状況に応じて特性変換回路６００の最大電力を調整することも可能である。一例では、直流電力変換装置２０に接続された太陽光発電システムの発電状況に応じて、可変パラメータが調整される。以下、そのような例について、説明する。 [Adjustment of Maximum Power of Characteristic Conversion Circuit 600 According to Situation]
It is also possible to adjust the maximum power of the characteristic conversion circuit 600 according to the situation by adjusting the variable parameter. In one example, the variable parameter is adjusted according to the power generation status of the photovoltaic power generation system connected to the DC power converter 20. Hereinafter, such an example will be described.
　本実施形態の電力システム５００は、制御器５１を備えている。本実施形態では、具体的には、燃料電池発電システム４０は、制御器５１を含んでいる。ただし、制御器５１は、燃料電池発電システム４０に含まれていなくてもよい。 The power system 500 of this embodiment includes a controller 51. In the present embodiment, specifically, the fuel cell power generation system 40 includes a controller 51. However, the controller 51 may not be included in the fuel cell power generation system 40.
　一具体例では、制御器５１は、少なくとも１つの太陽光発電システムの発電出力に応じて、可変パラメータを変化させる。このようにすれば、太陽光発電システムの発電出力に応じて特性変換回路６００の出力電力を調整できる。 In one specific example, the controller 51 changes the variable parameter according to the power generation output of at least one solar power generation system. With this configuration, the output power of the characteristic conversion circuit 600 can be adjusted according to the power generation output of the solar power generation system.
　発電出力は、例えば、発電電圧、発電電力、発電電流等である。少なくとも１つの太陽光発電システムの発電出力は、少なくとも１つの太陽光発電システムに含まれた１つの太陽光発電システムの発電出力であってもよく、少なくとも１つの太陽光発電システムに含まれた複数の太陽光発電システムの発電出力により定まる値であってもよく、少なくとも１つの太陽光発電システムに含まれた全ての太陽光発電システムの発電出力により定まる値であってもよい。複数のまたは全ての太陽光発電システムの発電出力により定まる値は、合計値または平均値であり得る。具体的には、少なくとも１つの太陽光発電システムの発電出力は、太陽光発電システム３１および３２の一方の発電出力であってもよく、太陽光発電システム３１および３２の発電出力の合計値あるいは平均値であってもよい。 The generated output is, for example, generated voltage, generated power, generated current, etc. The power generation output of at least one photovoltaic power generation system may be the power generation output of one photovoltaic power generation system included in at least one photovoltaic power generation system, and a plurality of power generation outputs included in at least one photovoltaic power generation system may be included. It may be a value determined by the power generation output of the solar power generation system, or may be a value determined by the power generation output of all the solar power generation systems included in at least one solar power generation system. The value determined by the power output of a plurality or all of the photovoltaic power generation systems may be a total value or an average value. Specifically, the power generation output of at least one solar power generation system may be one power generation output of the solar power generation systems 31 and 32, and the total value or average of the power generation outputs of the solar power generation systems 31 and 32. It may be a value.
　一具体例では、発電出力は、少なくとも１つの太陽光発電システムの発電電圧である。制御器５１は、（ａ）発電電圧が閾値発電電圧を跨いで大きくなったときに、切替電流ｉswが小さくなるように可変パラメータを変化させる、または、（ｂ）発電電圧が大きいほど、切替電流ｉswが小さくなるように可変パラメータを変化させる。典型的には、太陽光発電システムの発電電圧が大きい場合、太陽光発電システムの発電電力は大きい。この具体例では、そのような場合に、切替電流ｉswが小さくなるように可変パラメータを変化させる。このようにすれば、特性変換回路６００の最大電力が小さくなる。このようにすれば、ＭＰＰＴ制御により特性変換回路６００から直流電力変換装置２０に取り出される電力が小さくなる。以上の理由で、この具体例によれば、過不足のない電力を直流電力変換装置２０に供給できる。 In one embodiment, the power output is the power voltage of at least one photovoltaic system. The controller 51 (a) changes the variable parameter so that the switching current isw becomes smaller when the power generation voltage increases over the threshold power generation voltage, or (b) switches as the power generation voltage increases. The variable parameter is changed so that the current i sw becomes small. Typically, when the generated voltage of the solar power generation system is high, the generated power of the solar power generation system is high. In this specific example, in such a case, the variable parameter is changed so that the switching current isw becomes small. By doing so, the maximum power of the characteristic conversion circuit 600 becomes small. By doing so, the power taken out from the characteristic conversion circuit 600 to the DC power conversion device 20 by the MPPT control becomes small. For the above reason, according to this specific example, it is possible to supply the DC power converter 20 with sufficient power.
　一具体例では、制御器５１は、発電出力を表す制御信号を用いて、可変パラメータを変化させる。このようにすれば、発電出力に応じた可変パラメータの調整を容易に実行できる。制御信号は、例えば、直流電力変換装置２０によって生成される。あるいは、電力システム５００は、発電出力を表す制御信号を生成する出力センサを備えていてもよい。 In one specific example, the controller 51 changes a variable parameter using a control signal that represents a power generation output. In this way, adjustment of the variable parameter according to the power generation output can be easily executed. The control signal is generated by the DC power converter 20, for example. Alternatively, power system 500 may include an output sensor that produces a control signal representative of the power output.
　なお、「状況に応じた特性変換回路６００の最大電力の調整」の記載内容は、第２および第４の実施形態にも適用可能である。 The description of “adjustment of the maximum power of the characteristic conversion circuit 600 according to the situation” is also applicable to the second and fourth embodiments.
　特性変換回路６００の具体例である特性変換回路６００Ｘを、図２６に示す。図２６から理解されるように、特性変換回路６００Ｘは、第１の実施形態の図８の特性変換回路１００Ｘに倣って構成できる。このため、特性変換回路６００Ｘの詳細な説明は割愛する。 FIG. 26 shows a characteristic conversion circuit 600X which is a specific example of the characteristic conversion circuit 600. As can be understood from FIG. 26, the characteristic conversion circuit 600X can be configured by imitating the characteristic conversion circuit 100X of FIG. 8 of the first embodiment. Therefore, detailed description of the characteristic conversion circuit 600X will be omitted.
（第４の実施形態）
　第４の実施形態に係る特性変換回路を採用することも可能である。以下、第４の実施形態に係る特性変換回路について説明する。以下では、第３の実施形態と同様の部分については、同一符号を付し、説明を省略することがある。 (Fourth Embodiment)
It is also possible to adopt the characteristic conversion circuit according to the fourth embodiment. The characteristic conversion circuit according to the fourth embodiment will be described below. In the following, the same parts as those in the third embodiment will be designated by the same reference numerals and the description thereof may be omitted.
　図２７および図２８は、第４の実施形態に係る電力システム７００のブロック図である。具体的には、図２７は、系統連系時の電力の流れの例を示している。図２８は、停電時の電力の流れの例を示している。 27 and 28 are block diagrams of a power system 700 according to the fourth embodiment. Specifically, FIG. 27 shows an example of the flow of electric power during grid interconnection. FIG. 28 shows an example of the flow of electric power at the time of power failure.
　図２７および図２８に示すように、電力システム７００は、基板７６０を有している。基板７６０は、燃料電池発電システム４０とパワーステーション１０とを接続する経路上に設けられている。基板７６０には、燃料電池発電システム４０から、具体的には第２ＤＣバス４３から、直流電力が供給される。基板７６０は、特性変換回路８００と、ＬＣフィルタ６１と、保護リレー６２と、を有する。 As shown in FIGS. 27 and 28, the power system 700 has a board 760. The substrate 760 is provided on the path connecting the fuel cell power generation system 40 and the power station 10. Direct current power is supplied to the substrate 760 from the fuel cell power generation system 40, specifically from the second DC bus 43. The substrate 760 has a characteristic conversion circuit 800, an LC filter 61, and a protection relay 62.
　特性変換回路８００は、燃料電池発電システム４０と直流電力変換装置２０とを接続する経路上、詳細には直流電力の経路上、に設けられている。特性変換回路８００は、特性変換制御を実行する。 The characteristic conversion circuit 800 is provided on the path connecting the fuel cell power generation system 40 and the DC power conversion device 20, specifically, on the path of DC power. The characteristic conversion circuit 800 executes characteristic conversion control.
　図２９Ａおよび図３０に、第４の実施形態に係る特性変換回路８００の出力特性を示す。図３１に、第４の実施形態に係る特性変換回路８００を示す。 29A and 30 show output characteristics of the characteristic conversion circuit 800 according to the fourth embodiment. FIG. 31 shows a characteristic conversion circuit 800 according to the fourth embodiment.
　第４の実施形態では、第１回路８１０は、第１フィードバック制御を、電圧電流制御回路１６０と協働して実行する。第２回路８２０は、第２フィードバック制御を、第１回路８１０および電圧電流制御回路１６０と協働して実行する。第１フィードバック制御および第２フィードバック制御の両方において、電流センサ１２８が用いられる。 In the fourth embodiment, the first circuit 810 executes the first feedback control in cooperation with the voltage/current control circuit 160. The second circuit 820 executes the second feedback control in cooperation with the first circuit 810 and the voltage/current control circuit 160. The current sensor 128 is used in both the first feedback control and the second feedback control.
　特性変換回路８００において、以下に説明する（ｉ）の出力電圧－出力電力特性および（ii）の出力電流－出力電力特性がもたらされるように、センサ出力が相対的に小さいときに第１フィードバック制御が実行されるとともにセンサ出力が相対的に大きいときに第２フィードバック制御が実行される。 In the characteristic conversion circuit 800, the first feedback control is performed when the sensor output is relatively small so that the output voltage-output power characteristic of (i) and the output current-output power characteristic of (ii) described below are provided. Is executed and the second feedback control is executed when the sensor output is relatively large.
　特性変換回路８００の（ｉ）の出力電圧－出力電力特性は、図２９Ａに示すような、特性変換回路８００の出力電圧がある値であるときに特性変換回路８００の出力電力が最大となる出力電圧－出力電力特性である。また、（ｉ）の出力電圧－出力電流特性は、図２９Ａおよび図３０に示すような、特性変換回路８００の出力電圧がある値を跨ぐ領域において特性変換回路８００の出力電圧が大きくなるほど特性変換回路８００の出力電流が小さくなる出力電圧－出力電流特性である。ここで、特性変換回路８００の出力電圧が上記ある値を跨ぐ領域は、特性変換回路８００の出力電圧が上記ある値より小さい第１の値から上記ある値より大きい第２の値までの領域である。上記のある値は、具体的には、第１の実施形態と同様、所定範囲内の値である。 The output voltage-output power characteristic (i) of the characteristic conversion circuit 800 is such that the output power of the characteristic conversion circuit 800 becomes maximum when the output voltage of the characteristic conversion circuit 800 has a certain value as shown in FIG. 29A. It is a voltage-output power characteristic. Further, the output voltage-output current characteristic of (i) is characteristic-converted as the output voltage of the characteristic conversion circuit 800 increases in a region where the output voltage of the characteristic conversion circuit 800 crosses a certain value as shown in FIGS. 29A and 30. This is an output voltage-output current characteristic in which the output current of the circuit 800 becomes small. Here, the region where the output voltage of the characteristic conversion circuit 800 crosses the certain value is the region from the first value where the output voltage of the characteristic conversion circuit 800 is smaller than the certain value to the second value which is larger than the certain value. is there. The above-mentioned certain value is specifically a value within a predetermined range, as in the first embodiment.
　上述のとおり、直流電力変換装置２０は、出力電圧が所定範囲内にあるときに出力電力が最大になる太陽光発電システムのＭＰＰＴ制御を実行できるように設計されている。本実施形態では、特性変換回路８００は、出力電圧がその所定範囲内の値であるときに出力電力が最大となる上記（ｉ）の出力電圧－出力電力特性を有する。また、本実施形態では、特性変換回路８００は、出力電圧がある値を跨ぐ領域において特性変換回路８００の出力電圧が大きくなるほど特性変換回路８００の出力電流が小さくなる出力電圧－出力電流特性を有する。燃料電池発電システムの出力電圧－出力電力特性は、ＭＰＰＴ制御による電力の取り出しに必ずしも適していない。しかし、上記（ｉ）の出力電圧－出力電力特性を有する特性変換回路８００は、直流電力変換装置２０を用いてＭＰＰＴ制御を実行することにより燃料電池発電システム４０から直流電力変換装置２０に電力を取り出すことを可能にする。 As described above, the DC power conversion device 20 is designed to be able to execute MPPT control of the solar power generation system that maximizes output power when the output voltage is within the predetermined range. In the present embodiment, the characteristic conversion circuit 800 has the output voltage-output power characteristic of (i) above in which the output power becomes maximum when the output voltage has a value within the predetermined range. Further, in the present embodiment, the characteristic conversion circuit 800 has an output voltage-output current characteristic in which the output current of the characteristic conversion circuit 800 decreases as the output voltage of the characteristic conversion circuit 800 increases in a region where the output voltage crosses a certain value. .. The output voltage-output power characteristic of the fuel cell power generation system is not necessarily suitable for power extraction by MPPT control. However, the characteristic conversion circuit 800 having the output voltage-output power characteristic of the above (i) outputs power from the fuel cell power generation system 40 to the DC power conversion device 20 by executing MPPT control using the DC power conversion device 20. Allow to take out.
　また、特性変換回路８００によれば、ＭＰＰＴ制御に基づいて燃料電池発電システム４０から直流電力変換装置２０に大きな電力を取り出し易い。以下、この点について、図２９Ａおよび図２９Ｂを参照しながら説明する。 Further, according to the characteristic conversion circuit 800, it is easy to extract a large amount of power from the fuel cell power generation system 40 to the DC power conversion device 20 based on the MPPT control. Hereinafter, this point will be described with reference to FIGS. 29A and 29B.
　上述のように、特性変換回路８００の出力電圧が上記ある値を跨ぐ領域において特性変換回路８００の出力電圧が大きくなるほど特性変換回路８００の出力電流が小さくなる出力電圧－出力電流特性をもたらす。この出力電圧－出力電流特性により、図２９Ａに示すように、特性変換回路８００の出力電圧－出力電力特性のグラフは、上記ある値を跨ぐ領域において、出力電圧に対して出力電力が上に凸の曲線状となり得る。典型例では、特性変換回路８００の出力電圧－出力電力特性のグラフは、出力電圧が上記ある値のときに出力電力が最大となる単一ピークのグラフである。 As described above, as the output voltage of the characteristic conversion circuit 800 increases in the region where the output voltage of the characteristic conversion circuit 800 crosses the certain value, the output current-output current characteristic of the characteristic conversion circuit 800 decreases. Due to this output voltage-output current characteristic, as shown in FIG. 29A, in the graph of the output voltage-output power characteristic of the characteristic conversion circuit 800, the output power is convex upward with respect to the output voltage in the region crossing the certain value. Can be curved. In a typical example, the graph of the output voltage-output power characteristic of the characteristic conversion circuit 800 is a single-peak graph in which the output power becomes maximum when the output voltage has the above-mentioned certain value.
　仮に、特性変換回路８００の出力電圧－出力電力特性のグラフが。図２９Ｂに示すような、出力電圧に対して出力電力が上に凸の直線状であったとする。この場合において、ＭＰＰＴ制御を実行したものの、動作点が最大電力点からずれた点に調整されたとする。具体的には、特性変換回路８００の出力電圧が、最大電力点の出力電圧Ｖtargetからずれた電圧Ｖrealに調整されたとする。この場合、特性変換回路８００の出力電力は、動作点が最大電力点に調整された場合に比べ、減少する。図２９Ｂでは、この減少幅をδＰBと記載する。 Suppose that a graph of the output voltage-output power characteristic of the characteristic conversion circuit 800 is shown. It is assumed that the output power has a linear shape that is convex upward with respect to the output voltage, as shown in FIG. In this case, it is assumed that the MPPT control is executed but the operating point is adjusted to a point deviating from the maximum power point. Specifically, it is assumed that the output voltage of the characteristic conversion circuit 800 is adjusted to the voltage V real deviated from the output voltage V target at the maximum power point. In this case, the output power of the characteristic conversion circuit 800 decreases as compared with the case where the operating point is adjusted to the maximum power point. In FIG. 29B, this decrease width is described as δP B.
　一方、図２９Ａの例においても、特性変換回路８００の出力電圧が最大電力点の出力電圧Ｖtargetからずれた電圧Ｖrealに調整されると、特性変換回路８００の出力電力は、動作点が最大電力点に調整された場合と比べ、減少する。図２９Ａでは、この減少幅をδＰAと記載する。 On the other hand, also in the example of FIG. 29A, when the output voltage of the characteristic conversion circuit 800 is adjusted to the voltage V real which is deviated from the output voltage V target of the maximum power point, the output power of the characteristic conversion circuit 800 has the maximum operating point. Compared with the case of adjusting to the power point, it decreases. In FIG. 29A, this reduction width is described as δP A.
　上述のように、特性変換回路８００の出力電圧－出力電力特性のグラフが直線状である場合も曲線状である場合も、動作点が最大電力点からずれると、特性変換回路８００の出力電力は減少する。しかし、その減少幅は異なる。具体的には、図２９Ａの場合の減少幅δＰAは、図２９Ｂの減少幅δＰBよりも小さい。このように、出力電圧－出力電力特性のグラフが上に凸の曲線状であることは、上記のずれに起因する出力電力の減少幅を抑え、燃料電池発電システム４０から直流電力変換装置２０へと取り出される電力の減少幅を抑える観点から有利である。 As described above, regardless of whether the graph of the output voltage-output power characteristic of the characteristic conversion circuit 800 is linear or curved, if the operating point deviates from the maximum power point, the output power of the characteristic conversion circuit 800 becomes Decrease. However, the amount of decrease is different. Specifically, the decrease width δP A in the case of FIG. 29A is smaller than the decrease width δP B of FIG. 29B. As described above, the fact that the graph of the output voltage-output power characteristic has a curved shape that is convex upward suppresses the reduction range of the output power due to the above-described deviation, and allows the fuel cell power generation system 40 to move to the DC power conversion device 20. Therefore, it is advantageous from the viewpoint of suppressing the reduction range of the electric power taken out.
　第１の実施形態と同様、第４の実施形態の特性変換回路８００の出力特性には、ＭＰＰＴ制御の方式および分解能に起因する出力電力の減少幅を抑えることができるというメリットがある。この出力特性には、現実的なメリットがある。また、この出力特性には、特性変換回路８００のコンパティビリティを高め、採用可能な直流電力変換装置２０の制約を小さくするというメリットがある。 Similar to the first embodiment, the output characteristic of the characteristic conversion circuit 800 of the fourth embodiment has an advantage that it is possible to suppress a decrease in output power due to the MPPT control method and resolution. This output characteristic has a real merit. In addition, this output characteristic has an advantage that the compatibility of the characteristic conversion circuit 800 is enhanced and the restrictions of the DC power conversion device 20 that can be adopted are reduced.
　また、（ii）の出力電流－出力電力特性は、図２９Ａおよび図３０に示すような、特性変換回路８００の出力電流が切替電流ｉswであるときに特性変換回路８００の出力電力が最大となる出力電流－出力電力特性である。ここで、切替電流ｉswは、第１フィードバック制御と第２フィードバック制御とが切り替わるときの特性変換回路８００の出力電流である。 The output current-output power characteristic of (ii) shows that the output power of the characteristic conversion circuit 800 is the maximum when the output current of the characteristic conversion circuit 800 is the switching current i sw as shown in FIGS. 29A and 30. The output current-output power characteristics are as follows. Here, the switching current isw is the output current of the characteristic conversion circuit 800 when the first feedback control and the second feedback control are switched.
　切替電流ｉswは、電流センサ１２８による特性変換回路８００の出力電流の検出の誤差に依存するとともに、可変パラメータを変化させると変化する。この点は、第３の実施形態と同様であるため、詳細な説明は割愛する。 The switching current isw depends on the error in detection of the output current of the characteristic conversion circuit 800 by the current sensor 128, and changes when the variable parameter is changed. Since this point is the same as the third embodiment, detailed description will be omitted.
　図２９Ａから理解されるように、本実施形態では、第１フィードバック制御と第２フィードバック制御により、特性変換回路８００は、特性変換回路８００の出力電圧が上記ある値よりも大きく開放電圧よりも小さい領域において、特性変換回路８００の出力電圧が大きくなるほど特性変換回路８００の出力電流が小さくなる出力電圧－出力電流特性をもたらす。また、特性変換回路８００の出力電圧が０よりも大きく上記ある値よりも小さい領域において、特性変換回路８００の出力電圧が大きくなるほど特性変換回路８００の出力電流が小さくなる出力電圧－出力電流特性をもたらす。ここで、開放電圧は、特性変換回路８００の出力電流がゼロであるときの特性変換回路８００の出力電圧である。 As understood from FIG. 29A, in the present embodiment, the characteristic conversion circuit 800 causes the output voltage of the characteristic conversion circuit 800 to be larger than the certain value and smaller than the open circuit voltage by the first feedback control and the second feedback control. In the region, the output voltage-output current characteristic of the characteristic conversion circuit 800 becomes smaller as the output voltage of the characteristic conversion circuit 800 becomes larger. Further, in the region where the output voltage of the characteristic conversion circuit 800 is larger than 0 and smaller than the above-mentioned certain value, the output voltage-output current characteristic becomes smaller as the output voltage of the characteristic conversion circuit 800 becomes larger. Bring Here, the open circuit voltage is the output voltage of the characteristic conversion circuit 800 when the output current of the characteristic conversion circuit 800 is zero.
　上記ある値よりも小さい値を第１の値と定義する。上記ある値よりも大きい値を第２の値と定義する。このとき、図２９Ａの例では、出力特性は、出力電圧が第１の値よりも大きく上記ある値よりも小さい領域と出力電圧が上記ある値よりも大きく第２の値よりも小さい領域の両方において、出力電圧が大きくなるほど出力電流が線形的に小さくなる特性である。つまり、出力特性は、上記の両方の領域において、出力電圧に対して出力電流が一次関数の形態で小さくなる特性である。これにより、出力特性は、上記の両方の領域において、出力電力が出力電圧に対して二次関数の形態で変化する特性となり得る。 Define a value smaller than the above value as the first value. A value larger than the above certain value is defined as a second value. At this time, in the example of FIG. 29A, the output characteristics have both an area in which the output voltage is larger than the first value and smaller than the certain value and an area in which the output voltage is larger than the certain value and smaller than the second value. In the above, the output current linearly decreases as the output voltage increases. That is, the output characteristic is a characteristic in which the output current decreases in the form of a linear function with respect to the output voltage in both of the above regions. As a result, the output characteristic can be a characteristic in which the output power changes in the form of a quadratic function with respect to the output voltage in both of the above regions.
　具体的には、図２９Ａの例では、出力特性は、出力電圧が０よりも大きく上記ある値よりも小さい領域と出力電圧が上記ある値から開放電圧の値までの領域の両方において、出力電圧が大きくなるほど出力電流が線形的に小さくなる特性である。つまり、出力特性は、上記の両方の領域において、出力電圧に対して出力電流が一次関数の形態で小さくなる特性である。これにより、出力特性は、上記の両方の領域において、出力電力が出力電圧に対して二次関数の形態で変化する特性となり得る。 Specifically, in the example of FIG. 29A, the output characteristics are such that the output voltage is in both the region where the output voltage is larger than 0 and smaller than the certain value and the region where the output voltage is from the certain value to the open circuit voltage value. The characteristic is that the output current becomes linearly smaller as becomes larger. That is, the output characteristic is a characteristic in which the output current decreases in the form of a linear function with respect to the output voltage in both of the above regions. As a result, the output characteristic can be a characteristic in which the output power changes in the form of a quadratic function with respect to the output voltage in both of the above regions.
　出力電圧－出力電力特性のグラフにおいて、電圧がゼロかつ電力がゼロである点を原点と定義する。出力電圧－出力電力特性のグラフにおいて、最大電力点は、電圧が上記ある値であり電力が最大である点と言える。出力電圧－出力電力特性のグラフにおいて、電圧が開放電圧であり電力がゼロである点を、開放電圧点と定義する。出力電圧－出力電力特性のグラフにおいて、原点と最大電力点とを結ぶ直線を第１直線と定義する。出力電圧－出力電力特性のグラフにおいて、最大電力点と開放電圧点とを結ぶ直線を第２直線と定義する。このとき、図２９Ａの例では、出力電圧－出力電力特性のグラフにおける出力電圧が第１の値よりも大きく上記ある値よりも小さい領域が、第１直線よりも高電力側にある。出力電圧－出力電力特性のグラフにおける出力電圧が上記ある値よりも大きく第２の値よりも小さい領域が、第２直線よりも高電力側にある。 In the graph of output voltage-output power characteristics, the point where the voltage is zero and the power is zero is defined as the origin. In the graph of the output voltage-output power characteristic, the maximum power point can be said to be the point where the voltage has the above-mentioned value and the power is maximum. In the graph of output voltage-output power characteristics, the point where the voltage is the open circuit voltage and the power is zero is defined as the open circuit voltage point. In the graph of the output voltage-output power characteristic, the straight line connecting the origin and the maximum power point is defined as the first straight line. In the graph of the output voltage-output power characteristic, the straight line connecting the maximum power point and the open circuit voltage point is defined as the second straight line. At this time, in the example of FIG. 29A, the region where the output voltage in the graph of the output voltage-output power characteristic is larger than the first value and smaller than the certain value is on the higher power side than the first straight line. A region where the output voltage in the graph of the output voltage-output power characteristic is larger than the certain value and smaller than the second value is on the higher power side than the second straight line.
　具体的には、図２９Ａの例では、出力電圧－出力電力特性のグラフにおける出力電圧が０よりも大きく上記ある値よりも小さい領域が、第１直線よりも高電力側にある。出力電圧－出力電力特性のグラフにおける出力電圧が上記ある値から開放電圧までの領域が、第２直線よりも高電力側にある。 Specifically, in the example of FIG. 29A, a region where the output voltage in the graph of the output voltage-output power characteristic is larger than 0 and smaller than the above certain value is on the higher power side than the first straight line. In the graph of the output voltage-output power characteristic, the region where the output voltage is from the certain value to the open circuit voltage is on the higher power side than the second straight line.
　第１フィードバック制御および第２フィードバック制御が相俟って、特性変換回路８００の出力電圧－出力電流特性は、図２９Ａおよび図３０の破線に示すものとなる。結果として、特性変換回路８００の出力電圧－出力電力特性は、図２９Ａの実線に示すような、単一ピークを有する上に凸のものとなる。 Combined with the first feedback control and the second feedback control, the output voltage-output current characteristic of the characteristic conversion circuit 800 becomes as shown by the broken lines in FIGS. 29A and 30. As a result, the output voltage-output power characteristic of the characteristic conversion circuit 800 has a single peak and an upward convex shape as shown by the solid line in FIG. 29A.
　上述のように、特性変換回路８００の上に凸である出力電圧－出力電力特性は、直流電力変換装置２０によるＭＰＰＴ制御を可能にする。特性変換回路８００のＭＰＰＴ制御は、直流電力変換装置２０によって実行され得る。 As described above, the output voltage-output power characteristic that is convex above the characteristic conversion circuit 800 enables the MPPT control by the DC power conversion device 20. The MPPT control of the characteristic conversion circuit 800 can be executed by the DC power conversion device 20.
　特性変換回路８００の構成について、さらに説明する。 The configuration of the characteristic conversion circuit 800 will be further described.
　図３１に示すように、第１回路８１０は、第１抵抗６２１と、第２抵抗６２２と、第６抵抗８５０と、電流センサ１２８と、第１シャントレギュレータ６２５と、を有する。第２回路８２０は、第６抵抗８５０と、電流センサ１２８と、センサ電圧調整回路８２０ａと、電圧電流変換回路８２０ｂと、を有する。電流センサ１２８および第６抵抗８５０は、第１回路８１０および第２回路８２０によって共有されている。フィードバック電流供給部１３０は、電流供給電源１３１と、第３抵抗１３２と、を有する。本実施形態では、電流供給電源１３１は、定電圧源である。 As shown in FIG. 31, the first circuit 810 includes a first resistor 621, a second resistor 622, a sixth resistor 850, a current sensor 128, and a first shunt regulator 625. The second circuit 820 includes a sixth resistor 850, a current sensor 128, a sensor voltage adjustment circuit 820a, and a voltage/current conversion circuit 820b. The current sensor 128 and the sixth resistor 850 are shared by the first circuit 810 and the second circuit 820. The feedback current supply unit 130 has a current supply power supply 131 and a third resistor 132. In the present embodiment, the current supply power source 131 is a constant voltage source.
　電圧電流制御回路１６０は、電流供給電源１３１から流出する電流が小さいほど、電圧電流制御回路１６０の入力電圧に対する出力電圧の比率を大きくする。このように、特性変換回路８００は、電流供給電源１３１から流出する電流に応じて上記比率が調整されるようになっている。 The voltage/current control circuit 160 increases the ratio of the output voltage to the input voltage of the voltage/current control circuit 160 as the current flowing out from the current supply power source 131 is smaller. As described above, in the characteristic conversion circuit 800, the ratio is adjusted according to the current flowing out from the current supply power source 131.
　第４の実施形態では、電流センサ１２８は、第３の実施形態と同様、図２２に示す構成を有する。電流センサ１２８が生成する第１センサ電圧Ｖ１は、上記の数式４で与えられる。ただし、電流センサ１２８としてホール素子方式の電流センサ等の他の電流センサを用い、その電流センサの出力を第１センサ電圧Ｖ１として用いてもよい。 In the fourth embodiment, the current sensor 128 has the configuration shown in FIG. 22 as in the third embodiment. The first sensor voltage V1 generated by the current sensor 128 is given by Equation 4 above. However, another current sensor such as a Hall element type current sensor may be used as the current sensor 128, and the output of the current sensor may be used as the first sensor voltage V1.
　第４の実施形態では、第１シャントレギュレータ６２５は、第３の実施形態と同様、図２１に示す構成を有する。第１シャントレギュレータ６２５により、第１参照電圧Ｖref1は、一定の第１基準電圧Ｖs1に追従する。 In the fourth embodiment, the first shunt regulator 625 has the configuration shown in FIG. 21 as in the third embodiment. The first shunt regulator 625 causes the first reference voltage V ref1 to follow the constant first reference voltage V s1 .
　図３１に示した第１回路８１０において、第１フィードバック制御における特性変換回路８００の出力電圧Ｖoutは、以下の数式９で与えられる。ここで、Ｒ６２１は第１抵抗６２１の抵抗値であり、Ｒ６２２は第２抵抗６２２の抵抗値であり、Ｒ８５０は第６抵抗８５０の抵抗値である。
Figure JPOXMLDOC01-appb-M000001
 In the first circuit 810 shown in FIG. 31, the output voltage V out of the characteristic conversion circuit 800 in the first feedback control is given by the following Expression 9. Here, R621 is the resistance value of the first resistor 621, R622 is the resistance value of the second resistor 622, and R850 is the resistance value of the sixth resistor 850.
Figure JPOXMLDOC01-appb-M000001
　数式９から理解されるように、特性変換回路８００の出力電流が大きくなり第１センサ電圧Ｖ１が大きくなると、出力電圧Ｖoutは小さくなる。このように、第１センサ電圧Ｖ１は、出力電圧Ｖoutを調整するように作用する。 As can be understood from Expression 9, when the output current of the characteristic conversion circuit 800 increases and the first sensor voltage V1 increases, the output voltage V out decreases. In this way, the first sensor voltage V1 acts to regulate the output voltage Vout .
　具体的には、第１回路８１０による第１フィードバック制御において、第１センサ電圧Ｖ１が大きくなると、電流センサ１２８から第６抵抗８５０および接続点ｐｓをこの順に介して第１接続点ｐ１に流れる電流が大きくなる。第１シャントレギュレータ６２５により、第１参照電圧Ｖref1は、一定の第１基準電圧Ｖs1に追従する。この追従を実現するために、第２抵抗６２２には、一定の電流が流れる。このことは、第６抵抗８５０を第１接続点ｐ１に向かって流れる上記電流が大きくなると、第１抵抗６２１を第１接続点ｐ１に向かって流れる電流が小さくなることを意味する。この電流が小さくなるということは、第１抵抗６２１で生じる電圧が小さくなることを意味する。 Specifically, in the first feedback control by the first circuit 810, when the first sensor voltage V1 increases, the current flowing from the current sensor 128 to the first connection point p1 through the sixth resistor 850 and the connection point ps in this order. Will grow. The first shunt regulator 625 causes the first reference voltage V ref1 to follow the constant first reference voltage V s1 . In order to realize this tracking, a constant current flows through the second resistor 622. This means that when the current flowing through the sixth resistor 850 toward the first connection point p1 increases, the current flowing through the first resistor 621 toward the first connection point p1 decreases. The reduction of this current means that the voltage generated in the first resistor 621 is reduced.
　図３１を参照した説明を踏まえて、第１フィードバック制御における第１回路８１０の動作を以下のように説明できる。特性変換回路８００の出力電流が大きくなると、第１接続点ｐ１の電圧が第１参照電圧Ｖref1に追従した状態で第１抵抗６２１において生じる電圧が小さくなる。その結果、特性変換回路８００の出力電圧Ｖoutが小さくなる。このようにして、第１フィードバック制御により、図２９Ａおよび図３０に示すような、特性変換回路８００の出力電圧が大きくなるほど特性変換回路８００の出力電流が小さくなる出力電圧－出力電流特性が得られる。 Based on the description with reference to FIG. 31, the operation of the first circuit 810 in the first feedback control can be described as follows. When the output current of the characteristic conversion circuit 800 increases, the voltage generated in the first resistor 621 decreases with the voltage at the first connection point p1 following the first reference voltage V ref1 . As a result, the output voltage V out of the characteristic conversion circuit 800 decreases. In this manner, the first feedback control provides output voltage-output current characteristics as shown in FIGS. 29A and 30, in which the output current of the characteristic conversion circuit 800 decreases as the output voltage of the characteristic conversion circuit 800 increases. ..
　また、第１フィードバック制御により、特性変換回路８００の開放電圧が制御される。ここで、開放電圧は、特性変換回路８００の出力電流がゼロであるときの特性変換回路８００の出力である。特性変換回路８００の出力電流がゼロなので、数式４においてＩloadがゼロになり、Ｖ１はバイアス電圧Ｖbiasに等しくなる。したがって、数式９により規定されるＶoutが固定値となる。この固定値が、特性変換回路８００の開放電圧に対応する。このように、本実施形態では、第１シャントレギュレータ６２５と電圧電流制御回路１６０の働きにより、電圧電流制御回路１６０の出力電圧Ｖoutが数式９によって決まる電圧になるように第１電流ｉ１が制御されることにより、開放電圧が規定値に設定される。 Further, the open circuit voltage of the characteristic conversion circuit 800 is controlled by the first feedback control. Here, the open circuit voltage is the output of the characteristic conversion circuit 800 when the output current of the characteristic conversion circuit 800 is zero. Since the output current of the characteristic conversion circuit 800 is zero, I load becomes zero in Formula 4, and V1 becomes equal to the bias voltage V bias . Therefore, V out defined by Expression 9 has a fixed value. This fixed value corresponds to the open circuit voltage of the characteristic conversion circuit 800. As described above, in the present embodiment, the first shunt regulator 625 and the voltage/current control circuit 160 work to control the first current i1 so that the output voltage V out of the voltage/current control circuit 160 becomes a voltage determined by Expression 9. As a result, the open circuit voltage is set to the specified value.
　第４の実施形態では、第３の実施形態と同様、第２センサ電圧Ｖ２は、上記の数式５で与えられる。Ｖ２＜Ｖ３のときの調整電流ｉ３は、上記の数式６で与えられる。Ｖ２≧Ｖ３のときの調整電流ｉ３は、上記の数式７で与えられる。 In the fourth embodiment, as in the third embodiment, the second sensor voltage V2 is given by Equation 5 above. The adjustment current i3 when V2<V3 is given by the above-mentioned formula 6. The adjustment current i3 when V2≧V3 is given by the above-mentioned formula 7.
　一方、第４の実施形態では、出力電圧Ｖoutは、第３の実施形態で説明した数式８とは異なる数式で与えられる。具体的には、第１シャントレギュレータ６２５により、第１参照電圧Ｖref1は、一定の第１基準電圧Ｖs1に追従する。出力電圧Ｖoutは、以下の数式１０で与えられる。ここで、Ｒ６２１は、第１抵抗６２１の抵抗値である。Ｒ６２２は、第２抵抗６２２の抵抗値であり、Ｒ８５０は第６抵抗８５０の抵抗値である。数式１０は、電流センサ１２８からのセンサ出力（具体的には第１センサ電圧Ｖ１）が大きくなるほど、また、調整電流ｉ３が大きくなるほど特性変換回路８００の出力電圧Ｖoutが小さくなることを示している。
Figure JPOXMLDOC01-appb-M000002
 On the other hand, in the fourth embodiment, the output voltage V out is given by a mathematical formula different from the mathematical formula 8 described in the third embodiment. Specifically, the first shunt regulator 625 causes the first reference voltage V ref1 to follow the constant first reference voltage V s1 . The output voltage V out is given by Equation 10 below. Here, R621 is the resistance value of the first resistor 621. R622 is the resistance value of the second resistor 622, and R850 is the resistance value of the sixth resistor 850. Expression 10 indicates that the output voltage V out of the characteristic conversion circuit 800 decreases as the sensor output from the current sensor 128 (specifically, the first sensor voltage V1) increases and the adjustment current i3 increases. There is.
Figure JPOXMLDOC01-appb-M000002
　数式１０および図３０から理解されるように、調整電流ｉ３が流れると、出力電圧Ｖoutは小さくなる。このように、調整電流ｉ３は、出力電圧Ｖoutを調整するように作用する。調整電流ｉ３を、出力電圧調整電流ｉ３と称することができる。また、第２回路８２０を、調整回路と称することができる。 As can be understood from Expression 10 and FIG. 30, when the adjustment current i3 flows, the output voltage V out decreases. In this way, the adjustment current i3 acts to adjust the output voltage V out . The adjustment current i3 can be referred to as the output voltage adjustment current i3. Further, the second circuit 820 can be referred to as an adjustment circuit.
［電流センサ１２８の個体ばらつきとその抑制］
　第３の実施形態で述べたとおり、電流センサ１２８には、個体ばらつきがあることがある。しかし、第４の実施形態によれば、第３の実施形態と同様、個体ばらつきの影響を抑える調整が可能である。この点について、以下、図３２から図３４を参照しつつ、詳細に説明する。図３２は、個体ばらつきの影響を抑える調整を行う前の、特性変換回路８００の出力特性を示す。図３３は、調整を説明するための図である。図３４は、個体ばらつきの影響を抑える調整を行った後の、特性変換回路８００の出力特性を示す。 [Individual variation of current sensor 128 and its suppression]
As described in the third embodiment, the current sensor 128 may have individual variations. However, according to the fourth embodiment, as in the third embodiment, it is possible to perform adjustment to suppress the influence of individual variation. This point will be described below in detail with reference to FIGS. 32 to 34. FIG. 32 shows the output characteristic of the characteristic conversion circuit 800 before adjustment for suppressing the influence of individual variation. FIG. 33 is a diagram for explaining the adjustment. FIG. 34 shows the output characteristic of the characteristic conversion circuit 800 after adjustment for suppressing the influence of individual variation.
　本実施形態では、電流センサ１２８は、図２２に示した構成を有する。シャント抵抗１２８ｒの抵抗値Ｒsense、ゲインＧおよびバイアス電圧Ｖbiasは、理想的には基準値である。しかし、抵抗値Ｒsense、ゲインＧおよび／またはバイアス電圧Ｖbiasには、公差の範囲の誤差があり得る。本実施形態では、電流センサ１２８は、シャント抵抗１２８ｒの抵抗値が基準値よりも大きいときには、シャント抵抗１２８ｒの抵抗値が基準値であるときに比べ、大きい第１センサ電圧Ｖ１を出力するように構成されている。電流センサ１２８は、ゲインＧが基準値よりも大きいときには、ゲインＧが基準値であるときに比べ、大きい第１センサ電圧Ｖ１を出力するように構成されている。電流センサ１２８は、バイアス電圧Ｖbiasが基準値よりも大きいときには、バイアス電圧Ｖbiasが基準値であるときに比べ、大きい第１センサ電圧Ｖ１を出力するように構成されている。 In the present embodiment, the current sensor 128 has the configuration shown in FIG. The resistance value R sense of the shunt resistor 128r, the gain G, and the bias voltage V bias are ideally reference values. However, the resistance value R sense , the gain G, and/or the bias voltage V bias may have an error in the tolerance range. In the present embodiment, the current sensor 128 outputs a larger first sensor voltage V1 when the resistance value of the shunt resistor 128r is larger than the reference value, compared to when the resistance value of the shunt resistor 128r is the reference value. It is configured. The current sensor 128 is configured to output a larger first sensor voltage V1 when the gain G is larger than the reference value, compared to when the gain G is the reference value. Current sensor 128, when the bias voltage V bias is larger than the reference value, than when the bias voltage V bias is the reference value, and is configured to output a large first sensor voltage V1.
　図３２において、横軸は、特性変換回路８００の出力電流を示す。図３２では、ゲインＧおよびバイアス電圧Ｖbiasが基準値にある場合において、抵抗値Ｒsenseを変化させた場合の特性変換回路８００の出力特性を示す。 In FIG. 32, the horizontal axis represents the output current of the characteristic conversion circuit 800. FIG. 32 shows the output characteristic of the characteristic conversion circuit 800 when the resistance value R sense is changed when the gain G and the bias voltage V bias are at the reference values.
　具体的には、図３２において、「特性変換回路の出力電圧（０）」は、シャント抵抗１２８ｒの抵抗値Ｒsenseが基準値にあるときの、特性変換回路８００の出力電圧を示す。「特性変換回路の出力電圧（＋）」は、抵抗値Ｒsenseが基準値よりも大きいときの、同出力電圧を示す。「特性変換回路の出力電圧（－）」は、抵抗値Ｒsenseが基準値よりも小さいときの、同出力電圧を示す。「調整電流ｉ３（０）」は、シャント抵抗１２８ｒの抵抗値Ｒsenseが基準値にあるときの、調整電流ｉ３を示す。「調整電流ｉ３（＋）」は、抵抗値Ｒsenseが基準値よりも大きいときの、調整電流ｉ３を示す。「調整電流ｉ３（－）」は、抵抗値Ｒsenseが基準値よりも小さいときの、調整電流ｉ３を示す。「特性変換回路の出力電力（０）」は、抵抗値Ｒsenseが基準値にあるときの、特性変換回路８００の出力電力を示す。「特性変換回路の出力電力（＋）」は、抵抗値Ｒsenseが基準値よりも大きいときの、同出力電力を示す。「特性変換回路の出力電力（－）」は、抵抗値Ｒsenseが基準値よりも小さいときの、同出力電力を示す。「切替電流ｉsw（０）」は、抵抗値Ｒsenseが基準値にあるときの、切替電流ｉswを示す。「切替電流ｉsw（＋）」は、抵抗値Ｒsenseが基準値よりも大きいときの、切替電流ｉswを示す。「切替電流ｉsw（－）」は、抵抗値Ｒsenseが基準値よりも小さいときの、切替電流ｉswを示す。上述のとおり、切替電流ｉswは、第１フィードバック制御と第２フィードバック制御とが切り替わるときの特性変換回路８００の出力電流である。 Specifically, in FIG. 32, “output voltage (0) of characteristic conversion circuit” indicates the output voltage of the characteristic conversion circuit 800 when the resistance value R sense of the shunt resistor 128r is at the reference value. The “output voltage (+) of the characteristic conversion circuit” indicates the same output voltage when the resistance value R sense is larger than the reference value. “Output voltage (−) of characteristic conversion circuit” indicates the same output voltage when the resistance value R sense is smaller than the reference value. “Adjustment current i3(0)” indicates the adjustment current i3 when the resistance value R sense of the shunt resistor 128r is at the reference value. “Adjustment current i3(+)” indicates the adjustment current i3 when the resistance value R sense is larger than the reference value. “Adjustment current i3(−)” indicates the adjustment current i3 when the resistance value R sense is smaller than the reference value. “Output power of characteristic conversion circuit (0)” indicates the output power of the characteristic conversion circuit 800 when the resistance value R sense is at the reference value. The “output power (+) of the characteristic conversion circuit” indicates the same output power when the resistance value R sense is larger than the reference value. “Output power (−) of characteristic conversion circuit” indicates the same output power when the resistance value R sense is smaller than the reference value. "Switching current i sw (0)" indicates the switching current i sw when the resistance value R sense is at the reference value. "Switching current i sw (+)" indicates the switching current i sw when the resistance value R sense is larger than the reference value. “Switching current i sw (−)” indicates the switching current i sw when the resistance value R sense is smaller than the reference value. As described above, the switching current isw is the output current of the characteristic conversion circuit 800 when the first feedback control and the second feedback control are switched.
　抵抗値Ｒsenseが基準値であるとき、最大電力点は、目標点にある。この状況は、図２９Ａおよび図３０に示したとおりである。 When the resistance value R sense is the reference value, the maximum power point is at the target point. This situation is as shown in FIGS. 29A and 30.
　抵抗値Ｒsenseが基準値にあるとき、切替電流ｉswは、目標電流に一致する。「切替電流ｉsw（０）」が、目標電流に対応する。図３２に示すように、抵抗値Ｒsenseが基準値よりも大きいと、抵抗値Ｒsenseが基準値にあるときに比べ、切替電流ｉswは小さい。反対に、抵抗値Ｒsenseが基準値よりも小さいと、抵抗値Ｒsenseが基準値にあるときに比べ、切替電流ｉswは大きい。 When the resistance value R sense is at the reference value, the switching current isw matches the target current. "Switching current isw (0)" corresponds to the target current. As shown in FIG. 32, when the resistance value R sense is larger than the reference value, the switching current isw is smaller than when the resistance value R sense is at the reference value. On the contrary, when the resistance value R sense is smaller than the reference value, the switching current i sw is larger than when the resistance value R sense is at the reference value.
　抵抗値Ｒsenseが基準値にあるとき、特性変換回路８００の最大電力は、目標電力に一致する。特性変換回路８００の出力電流が「切替電流ｉsw（０）」であるときの「特性変換回路の出力電力（０）」が、目標電力に対応する。抵抗値Ｒsenseが基準値よりも大きいと、抵抗値Ｒsenseが基準値にあるときに比べ、最大電力は小さい。反対に、抵抗値Ｒsenseが基準値よりも小さいと、抵抗値Ｒsenseが基準値にあるときに比べ、最大電力は大きい。 When the resistance value R sense is at the reference value, the maximum power of the characteristic conversion circuit 800 matches the target power. The “output power (0) of the characteristic conversion circuit” when the output current of the characteristic conversion circuit 800 is the “switching current i sw (0)” corresponds to the target power. When the resistance value R sense is larger than the reference value, the maximum power is smaller than when the resistance value R sense is at the reference value. On the contrary, when the resistance value R sense is smaller than the reference value, the maximum power is larger than when the resistance value R sense is at the reference value.
［可変電圧Ｖ４の調整の仕方の例］
　図３２に示されているように、シャント抵抗１２８ｒの抵抗値Ｒsenseの個体ばらつきは、特性変換回路８００の最大電力点のばらつきをもたらす。最大電力点のばらつきは、切替電流ｉswおよび最大電力のばらつきをもたらす。 [Example of how to adjust the variable voltage V4]
As shown in FIG. 32, individual variations in the resistance value R sense of the shunt resistor 128r cause variations in the maximum power point of the characteristic conversion circuit 800. The variation of the maximum power point causes the variation of the switching current isw and the maximum power.
　この点、本実施形態では、可変電圧Ｖ４を調整することにより、特性変換回路８００の切替電流ｉswを調整し、最大電力を調整することができる。 In this respect, in the present embodiment, by adjusting the variable voltage V4, it is possible to adjust the switching current isw of the characteristic conversion circuit 800 and adjust the maximum power.
　例えば、抵抗値Ｒsenseが基準値よりも小さい場合には、抵抗値Ｒsenseが基準値にある場合に比べて可変電圧Ｖ４を小さくして切替電流ｉswを調整することで、最大電力を目標電力に近づけることができる。 For example, when the resistance value R sense is smaller than the reference value, the variable voltage V4 is made smaller and the switching current isw is adjusted as compared with the case where the resistance value R sense is at the reference value, so that the maximum power is targeted. It can approach electric power.
　反対に、抵抗値Ｒsenseが基準値よりも大きい場合には、抵抗値Ｒsenseが基準値にある場合に比べて可変電圧Ｖ４を大きくして切替電流ｉswを調整することで、最大電力を目標電力に近づけることができる。 On the contrary, when the resistance value R sense is larger than the reference value, the variable voltage V4 is increased to adjust the switching current i sw to increase the maximum power as compared with the case where the resistance value R sense is at the reference value. It is possible to approach the target power.
　ここで、数式５から理解されるように、可変電圧Ｖ４を大きくすると、第２センサ電圧Ｖ２は大きくなる。反対に、可変電圧Ｖ４を小さくすると、第２センサ電圧Ｖ２は小さくなる。 Here, as understood from Formula 5, when the variable voltage V4 is increased, the second sensor voltage V2 is increased. On the contrary, when the variable voltage V4 is reduced, the second sensor voltage V2 is reduced.
　第２センサ電圧Ｖ２を大きくすると、特性変換回路８００の出力電流がより大きいときに調整電流ｉ３が流れ始めるようになる。反対に、第２センサ電圧Ｖ２を小さくすると、特性変換回路８００の出力電流がより小さいときに調整電流ｉ３が流れ始めるようになる。可変電圧Ｖ４を調整して第２センサ電圧Ｖ２を調整することにより、切替電流ｉswを調整できることを示している。この調整により、最大電力が調整される。 When the second sensor voltage V2 is increased, the adjusted current i3 starts to flow when the output current of the characteristic conversion circuit 800 is larger. On the contrary, when the second sensor voltage V2 is reduced, the adjusted current i3 starts to flow when the output current of the characteristic conversion circuit 800 is smaller. This shows that the switching current isw can be adjusted by adjusting the variable voltage V4 and the second sensor voltage V2. By this adjustment, the maximum power is adjusted.
　次に、可変電圧Ｖ４の調整が、調整電流ｉ３および最大電力を変化させ得ることについて、図３３を参照しながらさらに説明する。 Next, it will be further described with reference to FIG. 33 that the adjustment of the variable voltage V4 can change the adjustment current i3 and the maximum power.
　可変電圧Ｖ４の調整にあたっては、一例として、特性変換回路８００の出力部に出力電力を測定するための電力計、および、負荷としての電子負荷装置を接続する。 In adjusting the variable voltage V4, as an example, a power meter for measuring output power and an electronic load device as a load are connected to the output section of the characteristic conversion circuit 800.
　この調整例では、可変電圧Ｖ４の初期値は、十分に大きい電圧に設定される。そして、この調整例では、適切に調整された後の可変電圧Ｖ４の値は、初期値よりも小さいものとする。また、図３２に示すとおり厳密には第１フィードバック制御における特性変換回路８００の出力電流－出力電力特性は抵抗値Ｒsenseの個体ばらつきの影響で変動するが、図３３を参照して行う以下の説明ではこの変動は十分に小さく無視できるものとする。 In this adjustment example, the initial value of the variable voltage V4 is set to a sufficiently large voltage. Then, in this adjustment example, the value of the variable voltage V4 after being appropriately adjusted is smaller than the initial value. Strictly speaking, as shown in FIG. 32, the output current-output power characteristic of the characteristic conversion circuit 800 in the first feedback control fluctuates due to the individual variation of the resistance value R sense . In the explanation, it is assumed that this fluctuation is small enough to be ignored.
　図３３の（ａ）に示すように、特性変換回路８００を動作させる。特性変換回路８００からの出力電流を徐々に増加させ、特性変換回路８００の出力電力が目標値になるように調整する。この目標値は、調整後の最大電力点に対応する値である。次に、可変電圧Ｖ４を徐々に下げる。これにより、切替電流ｉswが徐々に小さくなり、可変電圧Ｖ４がある値であるときに最大電力の低下に伴って出力電力が目標値から低下し始める。この低下が始まるときの動作点に、特性変換回路８００の動作点を設定する。こうして、特性変換回路８００の出力電圧を最大電力点（目標値）に調整する。 As shown in FIG. 33A, the characteristic conversion circuit 800 is operated. The output current from the characteristic conversion circuit 800 is gradually increased to adjust the output power of the characteristic conversion circuit 800 to a target value. This target value is a value corresponding to the adjusted maximum power point. Next, the variable voltage V4 is gradually reduced. As a result, the switching current isw decreases gradually, and when the variable voltage V4 has a certain value, the output power starts to decrease from the target value as the maximum power decreases. The operating point of the characteristic conversion circuit 800 is set to the operating point when this decrease begins. In this way, the output voltage of the characteristic conversion circuit 800 is adjusted to the maximum power point (target value).
　電子負荷装置として、公知のものを利用できる。一例では、電子負荷装置は、定電流（ＣＣ：Constarnt Current）モードを備える。ＣＣモードを利用する場合、電子負荷装置を流れる電流である負荷電流の設定値を徐々に大きくすることによって、特性変換回路８００からの出力電流を徐々に増加させることができる。別例では、電子負荷装置は、定抵抗（ＣＲ：ConstrantResistance）モードを備える。ＣＲモードを利用する場合、電子負荷装置の抵抗である負荷抵抗の設定値を徐々に小さくすることによって、特性変換回路８００からの出力電流を徐々に増加させることができる。なお、電子負荷装置は、ＣＣモードおよびＣＲモードの両方を備えていてもよく、一方を備えていてもよい。 -A well-known electronic load device can be used. In one example, the electronic load device has a constant current (CC: Constant Current) mode. When using the CC mode, the output current from the characteristic conversion circuit 800 can be gradually increased by gradually increasing the set value of the load current, which is the current flowing through the electronic load device. In another example, the electronic load device has a constant resistance (CR) mode. When using the CR mode, the output current from the characteristic conversion circuit 800 can be gradually increased by gradually decreasing the set value of the load resistance that is the resistance of the electronic load device. The electronic load device may have both the CC mode and the CR mode, or may have one of them.
　図３３の（ｂ）に、調整電流ｉ３ａおよび切替電流ｉswaを示す。電流ｉ３ａは、可変電圧Ｖ４および第２センサ電圧Ｖ２の調整後の調整電流ｉ３である。電流ｉswaは、このときの切替電流ｉswである。なお、説明を理解し易くする目的で、切替電流ｉswaを、図３３の（ａ）においても示している。 FIG. 33B shows the adjustment current i3a and the switching current i swa . The current i3a is the adjusted current i3 after the adjustment of the variable voltage V4 and the second sensor voltage V2. The current iswa is the switching current isw at this time. Note that the switching current iswa is also shown in FIG. 33A for the purpose of facilitating understanding of the description.
　可変電圧Ｖ４の調整により、切替電流ｉswを調整することにより、最大電力点を抵抗値Ｒsenseが基準値にあるときの動作点に近づけることができる。 By adjusting the switching current isw by adjusting the variable voltage V4, the maximum power point can be brought close to the operating point when the resistance value R sense is at the reference value.
　また、数式４、数式５および数式６から、抵抗値Ｒsenseと調整電流ｉ３の関係は数式１１で与えられる。
Figure JPOXMLDOC01-appb-M000003
 From Equation 4, Equation 5, and Equation 6, the relationship between the resistance value R sense and the adjustment current i3 is given by Equation 11.
Figure JPOXMLDOC01-appb-M000003
　数式１１より、図３２に示したように、抵抗値Ｒsenseが大きいと調整電流ｉ３の傾きが大きくなり、反対に抵抗値Ｒsenseが小さいと調整電流ｉ３の傾きが小さくなることが理解される。この傾向は、図３４にも現れている。 From Expression 11, it is understood that, as shown in FIG. 32, when the resistance value R sense is large, the slope of the adjustment current i3 becomes large, and conversely, when the resistance value R sense is small, the slope of the adjustment current i3 becomes small. .. This tendency is also shown in FIG.
　また、電流センサ１２８が図２２に示す構成を有する場合、バイアス電圧ＶbiasおよびゲインＧの個体ばらつきもまた、特性変換回路８００の最大電力点のばらつきをもたらし得る。電流センサ１２８がホール素子方式の電流センサ等の他のセンサである場合も、電流センサ１２８の個体ばらつきに由来する誤差が、特性変換回路８００の最大電力点のばらつきをもたらし得る。しかし、これらの場合も、シャント抵抗１２８ｒの抵抗値Ｒsenseにばらつきがある場合と同様、可変電圧Ｖ４の調整により、特性変換回路８００の最大電力点を目標点に近づけ、切替電流ｉswおよび最大電力を目標電流および目標電力に近づけることができる。 When the current sensor 128 has the configuration shown in FIG. 22, individual variations in the bias voltage V bias and the gain G can also cause variations in the maximum power point of the characteristic conversion circuit 800. Even when the current sensor 128 is another sensor such as a Hall element type current sensor, an error resulting from individual variation of the current sensor 128 may cause variation in the maximum power point of the characteristic conversion circuit 800. However, in these cases as well, as in the case where the resistance value R sense of the shunt resistor 128r varies, the maximum power point of the characteristic conversion circuit 800 is brought closer to the target point by adjusting the variable voltage V4, and the switching current i sw and the maximum value. The power can be brought close to the target current and the target power.
　特性変換回路８００の具体例である特性変換回路８００Ｘを、図３５に示す。図３５から理解されるように、特性変換回路８００Ｘは、第１の実施形態の図８の特性変換回路１００Ｘに倣って構成できる。このため、特性変換回路８００Ｘの詳細な説明は割愛する。 A characteristic conversion circuit 800X, which is a specific example of the characteristic conversion circuit 800, is shown in FIG. As can be understood from FIG. 35, the characteristic conversion circuit 800X can be configured following the characteristic conversion circuit 100X of FIG. 8 of the first embodiment. Therefore, detailed description of the characteristic conversion circuit 800X will be omitted.
　各実施形態に関する説明は、技術的に矛盾しない限り、相互に適用されうる。技術的に矛盾しない限り、各実施形態は、相互に組み合わされてもよい。例えば、図２７および図２８の二次連系ブレーカー８３の配置は、第４の実施形態のみならず、第１から第３の実施形態にも適用可能である。 The description regarding each embodiment can be applied to each other as long as there is no technical contradiction. The respective embodiments may be combined with each other as long as there is no technical conflict. For example, the arrangement of the secondary interconnection breaker 83 shown in FIGS. 27 and 28 is applicable not only to the fourth embodiment but also to the first to third embodiments.
　また、第４の実施形態では、燃料電池システム４０は、電圧検出回路５７および電流検出回路５８を含む。電圧検出回路５７は、燃料電池発電システム４０から二次連系ブレーカー８３を介して第１分岐部８５に交流電力を導く経路における電圧を検出する。電流検出回路５８は、上流側電路８８における第３接続点ｐ３と主幹ブレーカー８２との間の位置に設けられた電流センサと協働して、この位置を流れる電流を検出する。これらの検出回路５７および５８で得られた検出値は、電力システム７００の制御に利用され得る。例えば、制御器５１が、これらの検出回路５７および５８で得られた検出値に基づいて、保護リレー６２の開状態および閉状態を切り替える。検出回路５７および５８ならびにこれらを用いた制御は、第１から第３の実施形態にも適用可能である。 In addition, in the fourth embodiment, the fuel cell system 40 includes a voltage detection circuit 57 and a current detection circuit 58. The voltage detection circuit 57 detects the voltage in the path for guiding the AC power from the fuel cell power generation system 40 to the first branch section 85 via the secondary interconnection breaker 83. The current detection circuit 58 cooperates with a current sensor provided at a position between the third connection point p3 and the main breaker 82 in the upstream electric circuit 88 to detect the current flowing through this position. The detection values obtained by these detection circuits 57 and 58 can be used for controlling the power system 700. For example, the controller 51 switches the protection relay 62 between the open state and the closed state based on the detection values obtained by the detection circuits 57 and 58. The detection circuits 57 and 58 and the control using them are also applicable to the first to third embodiments.
　各実施形態に、種々の変更を適用することもできる。例えば、電力システムにおける太陽光発電システムの数は１つであってもよく、３つ以上であってもよい。電力システムは、太陽光発電システムを有していなくてもよい。直流電力変換装置は、パワーステーションに組み込まれていなくてもよい。電力システムは、蓄電装置、貯湯ユニットなどの図示した一部の要素を有していなくてもよい。また、発電部と負荷の接続経路は、図示したものに限られない。例えば、コンセント２６０を省略して第１負荷２５１に電力を供給することも可能である。 Various changes can be applied to each embodiment. For example, the number of solar power generation systems in the power system may be one, or may be three or more. The power system may not have a solar power generation system. The DC power converter does not have to be incorporated in the power station. The power system may not include some of the illustrated elements such as a power storage device and a hot water storage unit. Moreover, the connection path between the power generation unit and the load is not limited to the illustrated one. For example, it is possible to omit the outlet 260 and supply power to the first load 251.
［効果］
　上記で説明したように、本開示の第１態様に係る直流電力供給システムは、
　燃料電池発電システムと、
　前記燃料電池発電システムから出力された直流電力が入力される特性変換回路であって、特性変換制御を実行する特性変換回路と、を備え、
　前記特性変換制御は、前記特性変換回路の出力電圧がある値であるときに前記特性変換回路の出力電力が最大となる出力電圧－出力電力特性をもたらし、
　前記特性変換制御は、第１フィードバック制御および第２フィードバック制御を含み、
　前記第１フィードバック制御は、前記特性変換回路の出力電流が相対的に小さいときに行われる制御であり、
　前記第２フィードバック制御は、前記特性変換回路の出力電流が相対的に大きいときに行われる制御であり、
　前記第１フィードバック制御と前記第２フィードバック制御とが切り替わるときに、前記特性変換回路の出力電圧が上記ある値となる。 [effect]
As described above, the DC power supply system according to the first aspect of the present disclosure includes
A fuel cell power generation system,
A characteristic conversion circuit to which DC power output from the fuel cell power generation system is input, the characteristic conversion circuit performing characteristic conversion control,
The characteristic conversion control provides an output voltage-output power characteristic that maximizes the output power of the characteristic conversion circuit when the output voltage of the characteristic conversion circuit has a certain value,
The characteristic conversion control includes a first feedback control and a second feedback control,
The first feedback control is control performed when the output current of the characteristic conversion circuit is relatively small,
The second feedback control is control performed when the output current of the characteristic conversion circuit is relatively large,
When the first feedback control and the second feedback control are switched, the output voltage of the characteristic conversion circuit becomes the certain value.
　第１態様に係る直流電力供給システムは、燃料電池発電システムを含む。第１態様に係る直流電力供給システムと、太陽光発電システムのＭＰＰＴ制御を実行できるように設計された直流電力変換装置と、が接続された接続状態において、直流電力変換装置によりＭＰＰＴ制御が実行されることによって、燃料電池発電システムから直流電力変換装置に電力を取り出すことが可能である。 The DC power supply system according to the first aspect includes a fuel cell power generation system. In the connection state in which the DC power supply system according to the first aspect and the DC power conversion device designed to execute the MPPT control of the solar power generation system are connected, the MPPT control is executed by the DC power conversion device. By doing so, it is possible to extract electric power from the fuel cell power generation system to the DC power conversion device.
　例えば、第１態様において、
　特性変換回路の出力特性は、特性変換回路に含まれたアナログ回路によって定められていてもよい。 For example, in the first aspect,
The output characteristic of the characteristic conversion circuit may be determined by an analog circuit included in the characteristic conversion circuit.
　本開示の第２態様において、例えば、第１態様に係る直流電力供給システムでは、
　前記特性変換制御は、前記特性変換回路の電気出力に基づいて実行されてもよい。 In the second aspect of the present disclosure, for example, in the DC power supply system according to the first aspect,
The characteristic conversion control may be executed based on an electric output of the characteristic conversion circuit.
　第２態様によれば、特性変換制御の精度を高め易い。 According to the second aspect, it is easy to improve the accuracy of characteristic conversion control.
　本開示の第３態様において、例えば、第１態様または第２態様に係る直流電力供給システムでは、
　前記特性変換回路は、
　　電流センサと、少なくとも１つの分圧抵抗と、ＤＣＤＣコンバータである電圧電流制御回路と、を含んでいてもよく、
　　前記電流センサを用いて、前記特性変換回路の出力電流を前記特性変換制御に反映させてもよく、
　　前記少なくとも１つの分圧抵抗を用いて、前記特性変換回路の出力電圧を前記特性変換制御に反映させてもよく、
　　前記特性変換制御によって、前記電圧電流制御回路の変圧比を調整してもよい。 In the third aspect of the present disclosure, for example, in the DC power supply system according to the first aspect or the second aspect,
The characteristic conversion circuit,
A current sensor, at least one voltage dividing resistor, and a voltage/current control circuit that is a DCDC converter may be included,
Using the current sensor, the output current of the characteristic conversion circuit may be reflected in the characteristic conversion control,
The output voltage of the characteristic conversion circuit may be reflected in the characteristic conversion control using the at least one voltage dividing resistor,
The transformation ratio of the voltage/current control circuit may be adjusted by the characteristic conversion control.
　第３態様によれば、電圧電流制御回路の変圧比に、特性変換回路の出力電流および出力電圧を反映させることができる。 According to the third aspect, the output current and output voltage of the characteristic conversion circuit can be reflected in the transformation ratio of the voltage/current control circuit.
　本開示の第４態様において、例えば、第１から第３態様のいずれか１つに係る直流電力供給システムでは、
　前記第１フィードバック制御では、
　　前記第２フィードバック制御に比べ、前記出力電圧－出力電流特性における出力電圧の増加に対する出力電流の減少の比率が大きい、および／または
　　前記第２フィードバック制御に比べ、前記出力電圧－出力電流特性における出力電流の増加に対する出力電圧の減少の比率が小さくてもよい。 In the fourth aspect of the present disclosure, for example, in the DC power supply system according to any one of the first to third aspects,
In the first feedback control,
Compared to the second feedback control, the ratio of the output current decrease to the increase of the output voltage in the output voltage-output current characteristic is larger, and/or the output in the output voltage-output current characteristic than the second feedback control. The ratio of decrease in output voltage to increase in current may be small.
　第４態様によれば、特性変換回路の出力特性を太陽光発電システムの出力特性に近づけ易い。 According to the fourth aspect, it is easy to make the output characteristic of the characteristic conversion circuit close to the output characteristic of the solar power generation system.
　本開示の第５態様において、例えば、第１から第４態様のいずれか１つに係る直流電力供給システムでは、
　前記特性変換回路の出力電流がゼロであるときの前記特性変換回路の出力電圧を開放電圧と定義したとき、前記第１フィードバック制御により、前記開放電圧が制御されてもよい。 In the fifth aspect of the present disclosure, for example, in the DC power supply system according to any one of the first to fourth aspects,
When the output voltage of the characteristic conversion circuit when the output current of the characteristic conversion circuit is zero is defined as an open circuit voltage, the open circuit voltage may be controlled by the first feedback control.
　第５態様は、特性変換回路の出力電圧が過度に大きくなることを防止するのに適している。例えば、第５態様は、直流電力供給システムの出力電圧を直流電力変換装置に供給する場合において、直流電力変換装置に耐電圧を超える電圧が供給されるのを防止するのに適している。 The fifth mode is suitable for preventing the output voltage of the characteristic conversion circuit from becoming excessively large. For example, the fifth aspect is suitable for preventing a voltage exceeding the withstand voltage from being supplied to the DC power converter when the output voltage of the DC power supply system is supplied to the DC power converter.
　本開示の第６態様において、例えば、第１から第５態様のいずれか１つに係る直流電力供給システムでは、
　前記第１フィードバック制御は、前記特性変換回路の出力電流が相対的に小さく出力電圧が相対的に大きいときに行われる制御であって、前記特性変換回路の出力電圧が大きくなるほど前記特性変換回路の出力電流を小さくしかつ出力電力を小さくする制御であってもよく、
　前記第２フィードバック制御は、前記特性変換回路の出力電流が相対的に大きく出力電圧が相対的に小さいときに行われる制御であって、前記特性変換回路の出力電圧が大きくなるほど前記特性変換回路の出力電流を小さくしかつ出力電力を大きくする制御であってもよく、
　前記特性変換制御は、前記特性変換回路の出力電圧が前記ある値を跨ぐ領域において前記特性変換回路の出力電圧が大きくなるほど前記特性変換回路の出力電流が小さくなる出力電圧－出力電流特性をもたらしてもよい。 In the sixth aspect of the present disclosure, for example, in the DC power supply system according to any one of the first to fifth aspects,
The first feedback control is control performed when the output current of the characteristic conversion circuit is relatively small and the output voltage thereof is relatively large, and the first feedback control of the characteristic conversion circuit increases as the output voltage of the characteristic conversion circuit increases. It may be a control that reduces the output current and the output power,
The second feedback control is control performed when the output current of the characteristic conversion circuit is relatively large and the output voltage is relatively small, and the second feedback control of the characteristic conversion circuit increases as the output voltage of the characteristic conversion circuit increases. It may be a control to reduce the output current and increase the output power,
The characteristic conversion control brings about an output voltage-output current characteristic in which the output current of the characteristic conversion circuit decreases as the output voltage of the characteristic conversion circuit increases in a region where the output voltage of the characteristic conversion circuit crosses the certain value. Good.
　第６態様によれば、太陽光発電システムのＭＰＰＴ制御を実行できるように設計された直流電力変換装置を用いてＭＰＰＴ制御を実行することにより、燃料電池発電システムから直流電力変換装置に大きな電力を取り出し易い。 According to the sixth aspect, by executing the MPPT control using the DC power conversion device designed to execute the MPPT control of the solar power generation system, a large amount of power is supplied from the fuel cell power generation system to the DC power conversion device. Easy to take out.
　本開示の第７態様において、例えば、第１から第６態様のいずれか１つに係る直流電力供給システムでは、
　前記特性変換回路において、ＤＣＤＣコンバータである電圧電流制御回路と、前記第１フィードバック制御を行う第１フィードバック回路と、前記第２フィードバック制御を行う第２フィードバック回路と、が設けられていてもよく、
　前記第１フィードバック回路は、前記特性変換回路の出力電流および出力電圧に応じて変化する第１参照電圧が入力される第１シャントレギュレータを有していてもよく、
　前記第２フィードバック回路は、前記特性変換回路の出力電流および出力電圧に応じて変化する第２参照電圧が入力される第２シャントレギュレータを有していてもよく、
　前記第１フィードバック制御おいて、前記第１シャントレギュレータを用いて前記第１参照電圧が一定に維持されるように前記電圧電流制御回路の変圧比が調整されてもよく、
　前記第２フィードバック制御おいて、前記第２シャントレギュレータを用いて前記第２参照電圧が一定に維持されるように前記電圧電流制御回路の変圧比が調整されてもよい。 In the seventh aspect of the present disclosure, for example, in the DC power supply system according to any one of the first to sixth aspects,
In the characteristic conversion circuit, a voltage/current control circuit that is a DCDC converter, a first feedback circuit that performs the first feedback control, and a second feedback circuit that performs the second feedback control may be provided.
The first feedback circuit may include a first shunt regulator to which a first reference voltage that changes according to the output current and the output voltage of the characteristic conversion circuit is input.
The second feedback circuit may include a second shunt regulator to which a second reference voltage that changes according to the output current and the output voltage of the characteristic conversion circuit is input.
In the first feedback control, the transformation ratio of the voltage/current control circuit may be adjusted using the first shunt regulator so that the first reference voltage is maintained constant.
In the second feedback control, the transformation ratio of the voltage/current control circuit may be adjusted by using the second shunt regulator so that the second reference voltage is maintained constant.
　第７態様の回路構成によれば、第１フィードバック制御および第２フィードバック制御を実現できる。 According to the circuit configuration of the seventh aspect, the first feedback control and the second feedback control can be realized.
　第７態様において、例えば、
　前記第１フィードバック回路は、第１分圧抵抗を有していてもよく、
　前記第２フィードバック回路は、第２分圧抵抗を有していてもよく、
　前記第１フィードバック回路および前記第２フィードバック回路は、電流センサを共有していてもよく、
　前記第１分圧抵抗を用いて、前記特性変換回路の出力電圧を前記第１参照電圧に反映させてもよく、
　前記電流センサを用いて、前記特性変換回路の出力電流を前記第１参照電圧に反映させてもよく、
　前記第２分圧抵抗を用いて、前記特性変換回路の出力電圧を前記第２参照電圧に反映させてもよく、
　前記電流センサを用いて、前記特性変換回路の出力電流を前記第２参照電圧に反映させてもよい。
　このような回路構成によれば、第１参照電圧および第２参照電圧が得られる。 In the seventh aspect, for example,
The first feedback circuit may include a first voltage dividing resistor,
The second feedback circuit may include a second voltage dividing resistor,
The first feedback circuit and the second feedback circuit may share a current sensor,
The output voltage of the characteristic conversion circuit may be reflected on the first reference voltage by using the first voltage dividing resistor,
The output current of the characteristic conversion circuit may be reflected on the first reference voltage using the current sensor,
The output voltage of the characteristic conversion circuit may be reflected on the second reference voltage by using the second voltage dividing resistor,
The output current of the characteristic conversion circuit may be reflected in the second reference voltage using the current sensor.
According to such a circuit configuration, the first reference voltage and the second reference voltage can be obtained.
　本開示の第８態様において、例えば、第１から第６態様のいずれか１つに係る直流電力供給システムでは、
　前記特性変換回路は、
　　前記特性変換回路の出力電流の検出を行い、前記検出の結果を表すセンサ出力を出力する電流センサであって、前記特性変換回路の出力電流が大きくなるほど前記センサ出力を大きく出力する電流センサと、
　　調整器と、を含んでいてもよく、
　前記特性変換回路において、
　　（ｉ）前記特性変換回路の出力電圧が前記ある値であるときに前記特性変換回路の出力電力が最大となる出力電圧－出力電力特性がもたらされ、かつ、
　　（ii）前記第１フィードバック制御と前記第２フィードバック制御とが切り替わるときの前記特性変換回路の出力電流を切替電流と定義したとき、前記特性変換回路の出力電流が前記切替電流であるときに前記特性変換回路の出力電力が最大となる出力電流－出力電力特性がもたらされるように、
　前記センサ出力が相対的に小さいときに前記第１フィードバック制御が実行されるとともに前記センサ出力が相対的に大きいときに前記第２フィードバック制御が実行されてもよく、
　前記切替電流は、前記検出の誤差に依存するとともに、前記調整器の可変パラメータを変化させると変化してもよい。 In the eighth aspect of the present disclosure, for example, in the DC power supply system according to any one of the first to sixth aspects,
The characteristic conversion circuit,
A current sensor that detects the output current of the characteristic conversion circuit and outputs a sensor output that represents the result of the detection, and a current sensor that outputs the sensor output as the output current of the characteristic conversion circuit increases.
And a regulator, may be included,
In the characteristic conversion circuit,
(I) An output voltage-output power characteristic is obtained in which the output power of the characteristic conversion circuit becomes maximum when the output voltage of the characteristic conversion circuit has the certain value, and
(Ii) When the output current of the characteristic conversion circuit when the first feedback control and the second feedback control are switched is defined as a switching current, when the output current of the characteristic conversion circuit is the switching current, In order to provide the output current-output power characteristic that maximizes the output power of the characteristic conversion circuit,
The first feedback control may be executed when the sensor output is relatively small, and the second feedback control may be executed when the sensor output is relatively large,
The switching current depends on the detection error and may change when a variable parameter of the regulator is changed.
　上述のように、第１態様に係る直流電力供給システムと、太陽光発電システムのＭＰＰＴ制御を実行できるように設計された直流電力変換装置と、が接続された接続状態において、直流電力変換装置によりＭＰＰＴ制御が実行されることによって、燃料電池発電システムから直流電力変換装置に電力を取り出すことが可能である。第８態様に係る直流電力供給システムは、当該取り出される電力を調整するのに適している。 As described above, in the connection state in which the DC power supply system according to the first aspect and the DC power converter designed to execute the MPPT control of the solar power generation system are connected, By executing the MPPT control, it is possible to extract electric power from the fuel cell power generation system to the DC power conversion device. The DC power supply system according to the eighth aspect is suitable for adjusting the extracted power.
　第８態様の技術と、第７態様の技術と、を組み合わせてもよい。 The technology of the eighth aspect and the technology of the seventh aspect may be combined.
　第８態様において、例えば、
　前記センサ出力は、第１センサ電圧であってもよく、
　前記可変出力は、可変電圧であってもよく、
　前記第２回路は、前記第１センサ電圧および前記可変電圧に応じて変化する第２センサ電圧を生成するセンサ電圧調整回路を含んでいてもよい。
　このような態様によれば、可変電圧を第２センサ電圧に反映させることができる。可変電圧が反映された第２センサ電圧を特性変換回路における制御に用いることにより、切替電流の目標値からのずれを小さくし、出力電力の最大値の目標値からのずれを小さくすることができる。また、可変電圧を調整して切替電流を調整することにより、状況に応じて特性変換回路の出力電力の最大値を調整することも可能である。 In the eighth aspect, for example,
The sensor output may be a first sensor voltage,
The variable output may be a variable voltage,
The second circuit may include a sensor voltage adjustment circuit that generates a second sensor voltage that changes according to the first sensor voltage and the variable voltage.
According to such an aspect, the variable voltage can be reflected on the second sensor voltage. By using the second sensor voltage reflecting the variable voltage for the control in the characteristic conversion circuit, it is possible to reduce the deviation of the switching current from the target value and the deviation of the maximum value of the output power from the target value. .. Also, by adjusting the variable voltage and the switching current, it is possible to adjust the maximum value of the output power of the characteristic conversion circuit according to the situation.
　前記電流センサは、前記第１センサ電圧を出力するセンサ出力部を含んでいてもよく、
　前記センサ電圧調整回路は、
　　入力抵抗と、
　　帰還抵抗と、
　　前記入力抵抗を介して前記センサ出力部に接続されたセンサ入力端子と、前記可変電圧が入力される可変電圧入力端子と、前記帰還抵抗を介して前記センサ入力端子に接続された第２センサ電圧出力端子と、を含むセンサ電圧調整オペアンプであって、前記センサ入力端子および前記可変電圧入力端子の電圧差に基づいて前記第２センサ電圧を生成して前記第２センサ電圧出力端子から出力するセンサ電圧調整オペアンプと、を含んでいてもよい。 The current sensor may include a sensor output unit that outputs the first sensor voltage,
The sensor voltage adjustment circuit,
Input resistance,
Feedback resistor,
A sensor input terminal connected to the sensor output unit via the input resistor, a variable voltage input terminal to which the variable voltage is input, and a second sensor voltage connected to the sensor input terminal via the feedback resistor. A sensor voltage adjustment operational amplifier including an output terminal, the sensor generating the second sensor voltage based on a voltage difference between the sensor input terminal and the variable voltage input terminal and outputting the second sensor voltage from the second sensor voltage output terminal. A voltage adjustment operational amplifier may be included.
　前記第２回路は、前記第１センサ電圧が大きくなることによって前記第２センサ電圧が閾値電圧を跨いで変化したときに調整電流が流れ始める電圧電流変換回路を含んでいてもよく、
　前記調整電流が流れ始めたときに、前記第１フィードバック制御から前記第２フィードバック制御に切り替わってもよい。
　このような態様では、調整電流が流れ始めるタイミングで、第１フィードバック制御から第２フィードバック制御に切り替わる。電流が流れ始めるタイミングで制御が切り替えられる特性変換回路は、設計し易い。 The second circuit may include a voltage-current conversion circuit in which an adjustment current starts to flow when the second sensor voltage changes across a threshold voltage due to an increase in the first sensor voltage,
The first feedback control may be switched to the second feedback control when the adjustment current starts to flow.
In such a mode, the first feedback control is switched to the second feedback control at the timing when the regulated current starts to flow. The characteristic conversion circuit whose control is switched at the timing when the current starts to flow is easy to design.
　前記電圧電流変換回路は、
　　前記閾値電圧を出力する電圧供給電源と、
　　介在抵抗と、
　　前記介在抵抗を介して前記電圧供給電源に接続された電源入力端子と、前記第２センサ電圧が入力される第２センサ電圧入力端子と、制御電圧出力端子と、を含むトランジスタ駆動オペアンプであって、前記電源入力端子および前記第２センサ電圧入力端子の電圧差に基づいて制御電圧を生成して前記制御電圧出力端子から出力するトランジスタ駆動オペアンプと、
　　前記制御電圧が入力される制御端子と、前記介在抵抗を介して前記電圧供給電源に接続された第１端子と、前記調整電流を出力する第２端子と、を含む調整電流出力トランジスタと、を含んでいてもよい。 The voltage-current conversion circuit,
A voltage supply power source for outputting the threshold voltage,
Intervening resistance,
A transistor drive operational amplifier including a power supply input terminal connected to the voltage supply power supply via the intervening resistor, a second sensor voltage input terminal to which the second sensor voltage is input, and a control voltage output terminal. A transistor drive operational amplifier that generates a control voltage based on a voltage difference between the power supply input terminal and the second sensor voltage input terminal and outputs the control voltage from the control voltage output terminal,
An adjustment current output transistor including a control terminal to which the control voltage is input, a first terminal connected to the voltage supply power source via the intervening resistor, and a second terminal for outputting the adjustment current. May be included.
　第８態様において、例えば、
　前記センサ出力は、第１センサ電圧であってもよく、
　前記調整器は、前記第１センサ電圧を変圧するＤＣＤＣコンバータであってもよく、
　前記可変パラメータは、前記ＤＣＤＣコンバータの変圧比を変更するパラメータであってもよい。 In the eighth aspect, for example,
The sensor output may be a first sensor voltage,
The regulator may be a DCDC converter that transforms the first sensor voltage,
The variable parameter may be a parameter that changes a transformation ratio of the DCDC converter.
　前記センサ出力は、第１センサ電圧であってもよく、
　前記調整器は、分圧回路と、増幅回路と、を含んでいてもよく、
　前記可変パラメータは、前記分圧回路または前記増幅回路が有するパラメータであってもよく、
　前記センサ出力部と、前記分圧回路と、前記増幅回路と、はこの順に接続されていてもよい。 The sensor output may be a first sensor voltage,
The regulator may include a voltage divider circuit and an amplifier circuit,
The variable parameter may be a parameter included in the voltage dividing circuit or the amplifier circuit,
The sensor output unit, the voltage dividing circuit, and the amplifier circuit may be connected in this order.
　前記分圧回路は、可変抵抗を含んでいてもよく、
　前記可変パラメータは、前記可変抵抗の抵抗値であってもよい。 The voltage dividing circuit may include a variable resistor,
The variable parameter may be a resistance value of the variable resistor.
　前記増幅回路は、オペアンプと、前記オペアンプの帰還回路と、を含んでいてもよく、
　前記帰還回路は、可変抵抗を含んでいてもよく、
　前記可変パラメータは、前記可変抵抗の抵抗値であってもよい。 The amplifier circuit may include an operational amplifier and a feedback circuit of the operational amplifier,
The feedback circuit may include a variable resistor,
The variable parameter may be a resistance value of the variable resistor.
　本開示の第９態様において、例えば、第８態様に係る直流電力供給システムでは、
　前記センサ出力が大きくなるほど前記特性変換回路の出力電力を大きくする前記第１フィードバック制御を実行する第１回路と、
　前記センサ出力が大きくなるほど前記特性変換回路の出力電力を小さくする前記第２フィードバック制御を、前記第１回路と協働して実行する第２回路と、が設けられていてもよく、
　前記可変パラメータは、可変出力であってもよく、
　前記調整器は、前記可変出力を出力する可変出力電源であってもよい。 In the ninth aspect of the present disclosure, for example, in the DC power supply system according to the eighth aspect,
A first circuit that executes the first feedback control that increases the output power of the characteristic conversion circuit as the sensor output increases;
There may be provided a second circuit that cooperates with the first circuit to execute the second feedback control that reduces the output power of the characteristic conversion circuit as the sensor output increases.
The variable parameter may be a variable output,
The regulator may be a variable output power supply that outputs the variable output.
　第９態様の構成は、上記取り出される電力を調整可能な構成の一具体例である。 The configuration of the ninth aspect is one specific example of the configuration in which the extracted power can be adjusted.
　本開示の第１０態様に係る電力システムは、
　第１から第９態様のいずれか１つに係る直流電力供給システムと、
　出力電圧が所定範囲内にあるときに出力電力が最大になる太陽光発電システムに対して、ＭＰＰＴ制御を実行できるように設計された直流電力変換装置と、を備え、
　前記燃料電池発電システムで生成された直流電力は前記直流電力変換装置に供給され、
　前記特性変換回路は、前記燃料電池発電システムと前記直流電力変換装置とを接続する経路上に設けられ、
　前記ある値は、前記所定範囲内の値である。 A power system according to a tenth aspect of the present disclosure,
A DC power supply system according to any one of the first to ninth aspects,
A photovoltaic power generation system having a maximum output power when the output voltage is within a predetermined range, and a DC power conversion device designed to perform MPPT control,
DC power generated in the fuel cell power generation system is supplied to the DC power converter,
The characteristic conversion circuit is provided on a path connecting the fuel cell power generation system and the DC power conversion device,
The certain value is a value within the predetermined range.
　第１０態様に係る電力システムは、太陽光発電システムのＭＰＰＴ制御を実行できるように設計された直流電力変換装置を含む。第１０態様に係る電力システムによれば、その直流電力変換装置を用いてＭＰＰＴ制御を実行することにより、燃料電池発電システムから直流電力変換装置に電力を取り出し可能である。 The power system according to the tenth aspect includes a DC power conversion device designed to execute MPPT control of the solar power generation system. According to the power system of the tenth aspect, it is possible to extract power from the fuel cell power generation system to the DC power converter by executing the MPPT control using the DC power converter.
　本開示の第１１態様に係る電力システムは、
　第８態様または第９態様に係る直流電力供給システムと、
　出力電圧が所定範囲内にあるときに出力電力が最大になる太陽光発電システムに対して、ＭＰＰＴ制御を実行できるように設計された直流電力変換装置と、
　出力電圧が前記所定範囲内にあるときに出力電力が最大になる少なくとも１つの太陽光発電システムと、
　制御器と、を備え、
　前記燃料電池発電システムで生成された直流電力は前記直流電力変換装置に供給され、
　前記特性変換回路は、前記燃料電池発電システムと前記直流電力変換装置とを接続する経路上に設けられ、
　前記ある値は、前記所定範囲内の値であり、
　前記少なくとも１つの太陽光発電システムで生成された直流電力は、前記直流電力変換装置に供給され、
　前記制御器は、前記少なくとも１つの太陽光発電システムの発電出力に応じて、前記可変パラメータを変化させる。 An electric power system according to an eleventh aspect of the present disclosure is
A DC power supply system according to an eighth aspect or a ninth aspect;
A DC power conversion device designed to perform MPPT control for a photovoltaic power generation system in which output power is maximum when the output voltage is within a predetermined range,
At least one solar power generation system that maximizes output power when the output voltage is within the predetermined range;
And a controller,
DC power generated in the fuel cell power generation system is supplied to the DC power converter,
The characteristic conversion circuit is provided on a path connecting the fuel cell power generation system and the DC power conversion device,
The certain value is a value within the predetermined range,
DC power generated by the at least one photovoltaic system is supplied to the DC power converter,
The controller changes the variable parameter according to a power generation output of the at least one solar power generation system.
　第１１態様によれば、少なくとも１つの太陽光発電システムの発電出力に応じて特性変換回路の出力電力を調整できる。 According to the eleventh aspect, the output power of the characteristic conversion circuit can be adjusted according to the power generation output of at least one solar power generation system.
　本開示の第１２態様において、例えば、第１１態様に係る電力システムでは、
　前記発電出力は、発電電圧であってもよく、
　前記制御器は、前記発電電圧を表す制御信号を用いて、
　　（ａ）前記発電電圧が閾値発電電圧を跨いで大きくなったときに、前記切替電流が小さくなるように前記可変パラメータを変化させる、または、
　　（ｂ）前記発電電圧が大きいほど、前記切替電流が小さくなるように前記可変パラメータを変化させてもよい。 In the twelfth aspect of the present disclosure, for example, in the power system according to the eleventh aspect,
The power generation output may be a power generation voltage,
The controller uses a control signal representing the generated voltage,
(A) changing the variable parameter so that the switching current becomes small when the generated voltage becomes large across the threshold generated voltage, or
(B) The variable parameter may be changed so that the switching current decreases as the generated voltage increases.
　第１２態様は、過不足のない電力を直流電力変換装置に供給するのに適している。 The twelfth aspect is suitable for supplying a sufficient amount of power to the DC power converter.
　本開示の第１３態様において、例えば、第１０から第１２態様のいずれか１つに係る電力システムは、第１太陽光発電システムであって該第１太陽光発電システムで生成された直流電力は前記直流電力変換装置に供給される第１太陽光発電システムを備えていてもよく、
　前記直流電力変換装置は、第１ＤＣＤＣコンバータおよび第２ＤＣＤＣコンバータを含んでいてもよく、
　前記第１ＤＣＤＣコンバータは、ＭＰＰＴ制御によって、前記特性変換回路の出力電力を変化させてもよく、
　前記第２ＤＣＤＣコンバータは、ＭＰＰＴ制御によって、前記第１太陽光発電システムの出力電力を変化させてもよい。 In the thirteenth aspect of the present disclosure, for example, the power system according to any one of the tenth to twelfth aspects is a first photovoltaic power generation system, and the DC power generated by the first photovoltaic power generation system is You may include the 1st solar power generation system supplied to the said DC power converter device,
The DC power converter may include a first DCDC converter and a second DCDC converter,
The first DCDC converter may change the output power of the characteristic conversion circuit by MPPT control,
The second DCDC converter may change the output power of the first solar power generation system by MPPT control.
　第１３態様によれば、太陽光発電システムおよび特性変換回路を個別にＭＰＰＴ制御するマルチストリング型の直流電力変換装置を実現できる。 According to the thirteenth aspect, it is possible to realize a multi-string type DC power conversion device that individually performs MPPT control of the solar power generation system and the characteristic conversion circuit.
　本開示の第１４態様において、例えば、第１０から第１３態様のいずれか１つに係る電力システムは、
　　少なくとも１つの太陽光発電システムであって該少なくとも１つの太陽光発電システムで生成された直流電力は前記直流電力変換装置に供給される少なくとも１つの太陽光発電システムと、
　　蓄電装置と、を備えていてもよく、
　前記少なくとも１つの太陽光発電システムと、前記直流電力変換装置と、前記蓄電装置と、はこの順に接続されていてもよく、
　前記燃料電池発電システムと、前記特性変換回路と、前記直流電力変換装置と、前記蓄電装置と、はこの順に接続されていてもよい。 In a fourteenth aspect of the present disclosure, for example, a power system according to any one of the tenth to thirteenth aspects,
At least one photovoltaic power generation system, wherein the DC power generated by the at least one photovoltaic power generation system is supplied to the DC power conversion device;
And a power storage device,
The at least one solar power generation system, the DC power conversion device, and the power storage device may be connected in this order,
The fuel cell power generation system, the characteristic conversion circuit, the DC power conversion device, and the power storage device may be connected in this order.
　第１４態様によれば、太陽光発電システムからのみならず、燃料電池発電システムからも、蓄電装置を充電することができる。 According to the fourteenth aspect, the power storage device can be charged not only from the solar power generation system but also from the fuel cell power generation system.
　本開示の第１５態様において、例えば、第１０から第１４態様のいずれか１つに係る電力システムは、
　　少なくとも１つの太陽光発電システムであって該少なくとも１つの太陽光発電システムで生成された直流電力は前記直流電力変換装置に供給される少なくとも１つの太陽光発電システムと、
　　蓄電装置と、
　　直流電力を交流電力に変換するインバータと、
　　コンセントと、を備えていてもよく、
　前記少なくとも１つの太陽光発電システムと、前記直流電力変換装置と、前記インバータと、前記コンセントと、はこの順に接続されていてもよく、
　前記燃料電池発電システムと、前記特性変換回路と、前記直流電力変換装置と、前記インバータと、前記コンセントと、はこの順に接続されていてもよく、
　前記蓄電装置と、前記インバータと、前記コンセントと、はこの順に接続されていてもよい。 In a fifteenth aspect of the present disclosure, for example, a power system according to any one of the tenth to fourteenth aspects,
At least one photovoltaic power generation system, wherein the DC power generated by the at least one photovoltaic power generation system is supplied to the DC power conversion device;
A power storage device,
An inverter that converts DC power into AC power,
You may have an outlet and
The at least one solar power generation system, the DC power conversion device, the inverter, and the outlet may be connected in this order,
The fuel cell power generation system, the characteristic conversion circuit, the DC power conversion device, the inverter, and the outlet may be connected in this order,
The power storage device, the inverter, and the outlet may be connected in this order.
　第１５態様によれば、太陽光発電システムおよび蓄電装置から電力供給されるコンセントに、燃料電池発電システムからも電力供給できる。 According to the fifteenth aspect, power can be supplied from the fuel cell power generation system to the outlet supplied with power from the solar power generation system and the power storage device.
　本開示の第１６態様において、例えば、第１４態様または第１５態様に係る電力システムは、
　前記蓄電装置から前記燃料電池発電システムに電力を供給することができるように構成されていてもよい。 In the 16th aspect of the present disclosure, for example, a power system according to the 14th aspect or the 15th aspect,
Power may be supplied from the power storage device to the fuel cell power generation system.
　第１６態様によれば、停電時に、蓄電装置の電力により、燃料電池発電システムを起動させることができる。第１６態様によれば、停電時に燃料電池発電システムを起動させるための専用電源を省略することができる。 According to the sixteenth aspect, it is possible to activate the fuel cell power generation system by the power of the power storage device at the time of power failure. According to the sixteenth aspect, it is possible to omit the dedicated power supply for starting the fuel cell power generation system at the time of power failure.
　本開示は、特性変換回路を開示していると考えることもできる。具体的には、本開示に係る特性変換回路は、
　直流電力が入力され、特性変換制御を実行する特性変換回路であって
　前記特性変換制御は、前記特性変換回路の出力電圧がある値であるときに前記特性変換回路の出力電力が最大となる出力電圧－出力電力特性をもたらし、
　前記特性変換制御は、第１フィードバック制御および第２フィードバック制御を含み、
　前記第１フィードバック制御は、前記特性変換回路の出力電流が相対的に小さいときに行われる制御であり、
　前記第２フィードバック制御は、前記特性変換回路の出力電流が相対的に大きいときに行われる制御であり、
　前記第１フィードバック制御と前記第２フィードバック制御とが切り替わるときに、前記特性変換回路の出力電圧が上記ある値となる。 The present disclosure can also be considered as disclosing a characteristic conversion circuit. Specifically, the characteristic conversion circuit according to the present disclosure is
A characteristic conversion circuit to which direct-current power is input and which executes characteristic conversion control, wherein the characteristic conversion control is an output that maximizes the output power of the characteristic conversion circuit when the output voltage of the characteristic conversion circuit has a certain value. Results in voltage-output power characteristics,
The characteristic conversion control includes a first feedback control and a second feedback control,
The first feedback control is control performed when the output current of the characteristic conversion circuit is relatively small,
The second feedback control is control performed when the output current of the characteristic conversion circuit is relatively large,
When the first feedback control and the second feedback control are switched, the output voltage of the characteristic conversion circuit becomes the certain value.
　本開示に係る技術は、太陽光発電システム用に設計された直流電力変換装置と、燃料電池発電システムと、を有する電力システムに利用可能である。 The technology according to the present disclosure can be used for a power system including a DC power conversion device designed for a solar power generation system and a fuel cell power generation system.
１０　パワーステーション
１１，４３　ＤＣバス
１２，２１，２２，２３，４２，４５　ＤＣＤＣコンバータ
１３，４４　インバータ
２０　直流電力変換装置
２５　蓄電装置
２８　電力切替ユニット
２８ａ　系統電力入力部
２８ｂ　自立電力入力部
２８ｃ　電力出力部
３１，３２　太陽光発電システム
３６，３７　太陽光発電パネル
４０　燃料電池発電システム
４１　燃料電池
４６　ヒーター
４７　貯湯ユニット
５１　制御器
５２　低圧電源
５５　Ｄ１電源
６０，５６０，７６０　基板
６１　ＬＣフィルタ
６２　保護リレー
８０，９０　分電盤
８１，８２，８３，８５ａ，８５ｂ，８５ｃ，９２，９５ａ，９５ｂ，９５ｃ　ブレーカー
８５，９５　分岐部
８８，８９，９８，９９　電路
１００，１００Ｘ，１９０，１９０Ｘ，４００，６００，６００Ｘ，８００，８００Ｘ　特性変換回路
１１０，１２０，４１０，４２０　フィードバック回路
１１１，１１２，１１３，１２１，１２２，１２３，１３２，１４１，１４３，１９１，１９６，Ｒ１，Ｒ２，Ｒ３，ＦＲ１，ＦＲ２，ＦＲ３，ＦＲ４，ＶＲ１，６２１，６２２，８５０　抵抗
１１５，１２５，６２５　シャントレギュレータ
１１５Ａ，１２５Ａ，６２５Ａ　アノード
１１５Ｋ，１２５Ｋ，６２５Ｋ　カソード
１１５ａ，１２５ａ，６２５ａ　参照電圧端子
１１５о，１２４，１２６、１２５о，１７５，６２５о　オペアンプ
１１５ｔ，１２５ｔ，１２７，６２５ｔ　トランジスタ
１７０，１８０　調整器
１２８　電流センサ
１２８ａ　センサ出力部
１２８ｒ　シャント抵抗
１２８ｓ　電流センスアンプ
１２９，１３１　電源
１３０，１３０Ｘ、１９５，１９５Ｘ　フィードバック電流供給部
１３５，１９２　発光ダイオード
１４０，１９９　電流共振制御部
１４２，１６１，１６３ａ，１６３ｂ，１６４，１６７　コンデンサ
１４５，１９７　フォトトランジスタ
１４６　制御ＩＣ
１４７　定電流源
１４８，１４９ａ，１４９ｂ　端子
１５０，１９８　フォトカプラ
１６０，１６０Ｘ　電圧電流制御回路
１６２ａ，１６２ｂ　スイッチング素子
１６５　トランス
１６５ａ，１６５ｂ，１６５ｃ　巻線
１６６ａ，１６６ｂ　ダイオード
１７０ａ　分圧回路
１７０ｂ　増幅回路
２００　系統電源
２５１，２５２，２５３　負荷
２６０　コンセント
３００，５００，７００　電力システム
６１０，６２０，８１０，８２０　回路
６２０ａ，８２０ａ　センサ電圧調整回路
６２０ｂ，８２０ｂ　電圧電流変換回路
ｐ１，ｐ２，ｐ３，ｐｓ　接続点 10 power station 11,43 DC bus 12,21,22,23,42,45 DCDC converter 13,44 inverter 20 DC power converter 25 power storage device 28 power switching unit 28a system power input unit 28b self-sustained power input unit 28c power output Part 31, 32 Solar power generation system 36, 37 Solar power generation panel 40 Fuel cell power generation system 41 Fuel cell 46 Heater 47 Hot water storage unit 51 Controller 52 Low voltage power supply 55 D1 power supply 60, 560, 760 Substrate 61 LC filter 62 Protection relay 80 , 90 distribution board 81, 82, 83, 85a, 85b, 85c, 92, 95a, 95b, 95c Breaker 85, 95 Branching unit 88, 89, 98, 99 Electrical path 100, 100X, 190, 190X, 400, 600, 600X, 800, 800X Characteristic conversion circuit 110, 120, 410, 420 Feedback circuit 111, 112, 113, 121, 122, 123, 132, 141, 143, 191, 196, R1, R2, R3, FR1, FR2, FR3 , FR4, VR1, 621, 622, 850 resistors 115, 125, 625 shunt regulators 115A, 125A, 625A anodes 115K, 125K, 625K cathodes 115a, 125a, 625a reference voltage terminals 115о, 124, 126, 125о, 175, 625о operational amplifiers 115t, 125t, 127, 625t Transistor 170, 180 Regulator 128 Current sensor 128a Sensor output unit 128r Shunt resistor 128s Current sense amplifier 129, 131 Power supply 130, 130X, 195, 195X Feedback current supply unit 135, 192 Light emitting diode 140, 199 Current resonance controller 142, 161, 163a, 163b, 164, 167 Capacitor 145, 197 Phototransistor 146 Control IC
147 constant current sources 148, 149a, 149b terminals 150, 198 photocouplers 160, 160X voltage/ current control circuits 162a, 162b switching elements 165 transformers 165a, 165b, 165c windings 166a, 166b diodes 170a voltage divider circuit 170b amplification circuit 200 system power supply 251, 252, 253 Load 260 Outlet 300, 500, 700 Electric power system 610, 620, 810, 820 Circuit 620a, 820a Sensor voltage adjustment circuit 620b, 820b Voltage current conversion circuit p1, p2, p3, ps Connection point

Claims (16)

  1. 　燃料電池発電システムと、
    　前記燃料電池発電システムから出力された直流電力が入力される特性変換回路であって、特性変換制御を実行する特性変換回路と、を備え、
    　前記特性変換制御は、前記特性変換回路の出力電圧がある値であるときに前記特性変換回路の出力電力が最大となる出力電圧－出力電力特性をもたらし、
    　前記特性変換制御は、第１フィードバック制御および第２フィードバック制御を含み、
    　前記第１フィードバック制御は、前記特性変換回路の出力電流が相対的に小さいときに行われる制御であり、
    　前記第２フィードバック制御は、前記特性変換回路の出力電流が相対的に大きいときに行われる制御であり、
    　前記第１フィードバック制御と前記第２フィードバック制御とが切り替わるときに、前記特性変換回路の出力電圧が上記ある値となる、
    　直流電力供給システム。     A fuel cell power generation system,
    A characteristic conversion circuit to which DC power output from the fuel cell power generation system is input, the characteristic conversion circuit performing characteristic conversion control,
    The characteristic conversion control provides an output voltage-output power characteristic that maximizes the output power of the characteristic conversion circuit when the output voltage of the characteristic conversion circuit has a certain value,
    The characteristic conversion control includes a first feedback control and a second feedback control,
    The first feedback control is control performed when the output current of the characteristic conversion circuit is relatively small,
    The second feedback control is control performed when the output current of the characteristic conversion circuit is relatively large,
    When the first feedback control and the second feedback control are switched, the output voltage of the characteristic conversion circuit becomes the certain value.
    DC power supply system.
  2. 　前記特性変換制御は、前記特性変換回路の電気出力に基づいて実行される、
    　請求項１に記載の直流電力供給システム。     The characteristic conversion control is executed based on the electrical output of the characteristic conversion circuit,
    The DC power supply system according to claim 1.
  3. 　前記特性変換回路は、
    　　電流センサと、少なくとも１つの分圧抵抗と、ＤＣＤＣコンバータである電圧電流制御回路と、を含み、
    　　前記電流センサを用いて、前記特性変換回路の出力電流を前記特性変換制御に反映させ、
    　　前記少なくとも１つの分圧抵抗を用いて、前記特性変換回路の出力電圧を前記特性変換制御に反映させ、
    　　前記特性変換制御によって、前記電圧電流制御回路の変圧比を調整する、
    　請求項１または２に記載の直流電力供給システム。     The characteristic conversion circuit,
    A current sensor, at least one voltage dividing resistor, and a voltage/current control circuit that is a DCDC converter;
    Using the current sensor, the output current of the characteristic conversion circuit is reflected in the characteristic conversion control,
    The output voltage of the characteristic conversion circuit is reflected in the characteristic conversion control using the at least one voltage dividing resistor,
    By the characteristic conversion control, adjust the transformation ratio of the voltage-current control circuit,
    The DC power supply system according to claim 1 or 2.
  4. 　前記第１フィードバック制御では、
    　　前記第２フィードバック制御に比べ、前記出力電圧－出力電流特性における出力電圧の増加に対する出力電流の減少の比率が大きい、および／または
    　　前記第２フィードバック制御に比べ、前記出力電圧－出力電流特性における出力電流の増加に対する出力電圧の減少の比率が小さい、
    　請求項１から３のいずれか一項に記載の直流電力供給システム。     In the first feedback control,
    Compared to the second feedback control, the ratio of the output current decrease to the increase of the output voltage in the output voltage-output current characteristic is larger, and/or the output in the output voltage-output current characteristic than the second feedback control. The ratio of output voltage decrease to current increase is small,
    The DC power supply system according to any one of claims 1 to 3.
  5. 　前記特性変換回路の出力電流がゼロであるときの前記特性変換回路の出力電圧を開放電圧と定義したとき、前記第１フィードバック制御により、前記開放電圧が制御される、
    　請求項１から４のいずれか一項に記載の直流電力供給システム。     When the output voltage of the characteristic conversion circuit when the output current of the characteristic conversion circuit is zero is defined as an open circuit voltage, the open circuit voltage is controlled by the first feedback control.
    The DC power supply system according to any one of claims 1 to 4.
  6. 　前記第１フィードバック制御は、前記特性変換回路の出力電流が相対的に小さく出力電圧が相対的に大きいときに行われる制御であって、前記特性変換回路の出力電圧が大きくなるほど前記特性変換回路の出力電流を小さくしかつ出力電力を小さくする制御であり、
    　前記第２フィードバック制御は、前記特性変換回路の出力電流が相対的に大きく出力電圧が相対的に小さいときに行われる制御であって、前記特性変換回路の出力電圧が大きくなるほど前記特性変換回路の出力電流を小さくしかつ出力電力を大きくする制御であり、
    　前記特性変換制御は、前記特性変換回路の出力電圧が前記ある値を跨ぐ領域において前記特性変換回路の出力電圧が大きくなるほど前記特性変換回路の出力電流が小さくなる出力電圧－出力電流特性をもたらす、
    　請求項１から５のいずれか一項に記載の直流電力供給システム。     The first feedback control is control performed when the output current of the characteristic conversion circuit is relatively small and the output voltage thereof is relatively large, and the first feedback control of the characteristic conversion circuit increases as the output voltage of the characteristic conversion circuit increases. It is a control to reduce the output current and output power.
    The second feedback control is control performed when the output current of the characteristic conversion circuit is relatively large and the output voltage is relatively small, and the second feedback control of the characteristic conversion circuit increases as the output voltage of the characteristic conversion circuit increases. It is a control that reduces the output current and increases the output power.
    The characteristic conversion control provides an output voltage-output current characteristic in which the output current of the characteristic conversion circuit decreases as the output voltage of the characteristic conversion circuit increases in a region where the output voltage of the characteristic conversion circuit crosses the certain value.
    The DC power supply system according to any one of claims 1 to 5.
  7. 　前記特性変換回路において、ＤＣＤＣコンバータである電圧電流制御回路と、前記第１フィードバック制御を行う第１フィードバック回路と、前記第２フィードバック制御を行う第２フィードバック回路と、が設けられ、
    　前記第１フィードバック回路は、前記特性変換回路の出力電流および出力電圧に応じて変化する第１参照電圧が入力される第１シャントレギュレータを有し、
    　前記第２フィードバック回路は、前記特性変換回路の出力電流および出力電圧に応じて変化する第２参照電圧が入力される第２シャントレギュレータを有し、
    　前記第１フィードバック制御おいて、前記第１シャントレギュレータを用いて前記第１参照電圧が一定に維持されるように前記電圧電流制御回路の変圧比が調整され、
    　前記第２フィードバック制御おいて、前記第２シャントレギュレータを用いて前記第２参照電圧が一定に維持されるように前記電圧電流制御回路の変圧比が調整される、
    　請求項１から６のいずれか一項に記載の直流電力供給システム。     In the characteristic conversion circuit, a voltage/current control circuit that is a DCDC converter, a first feedback circuit that performs the first feedback control, and a second feedback circuit that performs the second feedback control are provided.
    The first feedback circuit includes a first shunt regulator to which a first reference voltage that changes according to the output current and the output voltage of the characteristic conversion circuit is input.
    The second feedback circuit has a second shunt regulator to which a second reference voltage that changes according to the output current and the output voltage of the characteristic conversion circuit is input.
    In the first feedback control, the transformation ratio of the voltage/current control circuit is adjusted using the first shunt regulator so that the first reference voltage is maintained constant.
    In the second feedback control, the transformation ratio of the voltage/current control circuit is adjusted by using the second shunt regulator so that the second reference voltage is maintained constant.
    The DC power supply system according to any one of claims 1 to 6.
  8. 　前記特性変換回路は、
    　　前記特性変換回路の出力電流の検出を行い、前記検出の結果を表すセンサ出力を出力する電流センサであって、前記特性変換回路の出力電流が大きくなるほど前記センサ出力を大きく出力する電流センサと、
    　　調整器と、を含み、
    　前記特性変換回路において、
    　　（ｉ）前記特性変換回路の出力電圧が前記ある値であるときに前記特性変換回路の出力電力が最大となる出力電圧－出力電力特性がもたらされ、かつ、
    　　（ii）前記第１フィードバック制御と前記第２フィードバック制御とが切り替わるときの前記特性変換回路の出力電流を切替電流と定義したとき、前記特性変換回路の出力電流が前記切替電流であるときに前記特性変換回路の出力電力が最大となる出力電流－出力電力特性がもたらされるように、
    　前記センサ出力が相対的に小さいときに前記第１フィードバック制御が実行されるとともに前記センサ出力が相対的に大きいときに前記第２フィードバック制御が実行され、
    　前記切替電流は、前記検出の誤差に依存するとともに、前記調整器の可変パラメータを変化させると変化する、
    　請求項１から６のいずれか一項に記載の直流電力供給システム。     The characteristic conversion circuit,
    A current sensor that detects the output current of the characteristic conversion circuit and outputs a sensor output that represents the result of the detection, and a current sensor that outputs the sensor output as the output current of the characteristic conversion circuit increases.
    And a regulator,
    In the characteristic conversion circuit,
    (I) An output voltage-output power characteristic is obtained in which the output power of the characteristic conversion circuit becomes maximum when the output voltage of the characteristic conversion circuit has the certain value, and
    (Ii) When the output current of the characteristic conversion circuit when the first feedback control and the second feedback control are switched is defined as a switching current, when the output current of the characteristic conversion circuit is the switching current, In order to provide the output current-output power characteristic that maximizes the output power of the characteristic conversion circuit,
    The first feedback control is executed when the sensor output is relatively small, and the second feedback control is executed when the sensor output is relatively large,
    The switching current depends on the detection error and changes when a variable parameter of the regulator is changed,
    The DC power supply system according to any one of claims 1 to 6.
  9. 　前記センサ出力が大きくなるほど前記特性変換回路の出力電力を大きくする前記第１フィードバック制御を実行する第１回路と、
    　前記センサ出力が大きくなるほど前記特性変換回路の出力電力を小さくする前記第２フィードバック制御を、前記第１回路と協働して実行する第２回路と、が設けられ、
    　前記可変パラメータは、可変出力であり、
    　前記調整器は、前記可変出力を出力する可変出力電源である、
    　請求項８に記載の直流電力供給システム。     A first circuit that executes the first feedback control that increases the output power of the characteristic conversion circuit as the sensor output increases;
    A second circuit that executes the second feedback control that reduces the output power of the characteristic conversion circuit as the sensor output increases, in cooperation with the first circuit,
    The variable parameter is a variable output,
    The regulator is a variable output power source that outputs the variable output,
    The DC power supply system according to claim 8.
  10. 　請求項１から９のいずれか一項に記載の直流電力供給システムと、
    　出力電圧が所定範囲内にあるときに出力電力が最大になる太陽光発電システムに対して、ＭＰＰＴ制御を実行できるように設計された直流電力変換装置と、を備え、
    　前記燃料電池発電システムで生成された直流電力は前記直流電力変換装置に供給され、
    　前記特性変換回路は、前記燃料電池発電システムと前記直流電力変換装置とを接続する経路上に設けられ、
    　前記ある値は、前記所定範囲内の値である、
    　電力システム。     A DC power supply system according to any one of claims 1 to 9,
    A photovoltaic power generation system having a maximum output power when the output voltage is within a predetermined range, and a DC power conversion device designed to perform MPPT control,
    DC power generated in the fuel cell power generation system is supplied to the DC power converter,
    The characteristic conversion circuit is provided on a path connecting the fuel cell power generation system and the DC power conversion device,
    The certain value is a value within the predetermined range,
    Power system.
  11. 　請求項８または９に記載の直流電力供給システムと、
    　出力電圧が所定範囲内にあるときに出力電力が最大になる太陽光発電システムに対して、ＭＰＰＴ制御を実行できるように設計された直流電力変換装置と、
    　出力電圧が前記所定範囲内にあるときに出力電力が最大になる少なくとも１つの太陽光発電システムと、
    　制御器と、を備え、
    　前記燃料電池発電システムで生成された直流電力は前記直流電力変換装置に供給され、
    　前記特性変換回路は、前記燃料電池発電システムと前記直流電力変換装置とを接続する経路上に設けられ、
    　前記ある値は、前記所定範囲内の値であり、
    　前記少なくとも１つの太陽光発電システムで生成された直流電力は、前記直流電力変換装置に供給され、
    　前記制御器は、前記少なくとも１つの太陽光発電システムの発電出力に応じて、前記可変パラメータを変化させる、
    　電力システム。     A DC power supply system according to claim 8 or 9,
    A DC power conversion device designed to perform MPPT control for a photovoltaic power generation system in which output power is maximum when the output voltage is within a predetermined range,
    At least one solar power generation system that maximizes output power when the output voltage is within the predetermined range;
    And a controller,
    DC power generated in the fuel cell power generation system is supplied to the DC power converter,
    The characteristic conversion circuit is provided on a path connecting the fuel cell power generation system and the DC power conversion device,
    The certain value is a value within the predetermined range,
    DC power generated by the at least one photovoltaic system is supplied to the DC power converter,
    The controller changes the variable parameter according to a power generation output of the at least one photovoltaic power generation system,
    Power system.
  12. 　前記発電出力は、発電電圧であり、
    　前記制御器は、前記発電電圧を表す制御信号を用いて、
    　　（ａ）前記発電電圧が閾値発電電圧を跨いで大きくなったときに、前記切替電流が小さくなるように前記可変パラメータを変化させる、または、
    　　（ｂ）前記発電電圧が大きいほど、前記切替電流が小さくなるように前記可変パラメータを変化させる、
    　請求項１１に記載の電力システム。     The power generation output is a power generation voltage,
    The controller uses a control signal representing the generated voltage,
    (A) changing the variable parameter so that the switching current becomes small when the generated voltage becomes large across the threshold generated voltage, or
    (B) The variable parameter is changed so that the switching current becomes smaller as the generated voltage becomes larger.
    The electric power system according to claim 11.
  13. 　前記電力システムは、第１太陽光発電システムであって該第１太陽光発電システムで生成された直流電力は前記直流電力変換装置に供給される第１太陽光発電システムを備え、
    　前記直流電力変換装置は、第１ＤＣＤＣコンバータおよび第２ＤＣＤＣコンバータを含み、
    　前記第１ＤＣＤＣコンバータは、ＭＰＰＴ制御によって、前記特性変換回路の出力電力を変化させ、
    　前記第２ＤＣＤＣコンバータは、ＭＰＰＴ制御によって、前記第１太陽光発電システムの出力電力を変化させる、
    　請求項１０から１２のいずれか一項に記載の電力システム。     The power system is a first solar power generation system, and includes a first solar power generation system in which DC power generated by the first solar power generation system is supplied to the DC power converter.
    The DC power converter includes a first DCDC converter and a second DCDC converter,
    The first DCDC converter changes the output power of the characteristic conversion circuit by MPPT control,
    The second DCDC converter changes the output power of the first solar power generation system by MPPT control,
    The power system according to any one of claims 10 to 12.
  14. 　前記電力システムは、
    　　少なくとも１つの太陽光発電システムであって該少なくとも１つの太陽光発電システムで生成された直流電力は前記直流電力変換装置に供給される少なくとも１つの太陽光発電システムと、
    　　蓄電装置と、を備え、
    　前記少なくとも１つの太陽光発電システムと、前記直流電力変換装置と、前記蓄電装置と、はこの順に接続され、
    　前記燃料電池発電システムと、前記特性変換回路と、前記直流電力変換装置と、前記蓄電装置と、はこの順に接続されている、
    　請求項１０から１３のいずれか一項に記載の電力システム。     The power system is
    At least one photovoltaic power generation system, wherein the DC power generated by the at least one photovoltaic power generation system is supplied to the DC power conversion device;
    A power storage device,
    The at least one solar power generation system, the DC power conversion device, and the power storage device are connected in this order,
    The fuel cell power generation system, the characteristic conversion circuit, the DC power conversion device, and the power storage device are connected in this order,
    The electric power system according to any one of claims 10 to 13.
  15. 　前記電力システムは、
    　　少なくとも１つの太陽光発電システムであって該少なくとも１つの太陽光発電システムで生成された直流電力は前記直流電力変換装置に供給される少なくとも１つの太陽光発電システムと、
    　　蓄電装置と、
    　　直流電力を交流電力に変換するインバータと、
    　　コンセントと、を備え、
    　前記少なくとも１つの太陽光発電システムと、前記直流電力変換装置と、前記インバータと、前記コンセントと、はこの順に接続され、
    　前記燃料電池発電システムと、前記特性変換回路と、前記直流電力変換装置と、前記インバータと、前記コンセントと、はこの順に接続され、
    　前記蓄電装置と、前記インバータと、前記コンセントと、はこの順に接続されている、
    　請求項１０から１４のいずれか一項に記載の電力システム。     The power system is
    At least one photovoltaic power generation system, wherein the DC power generated by the at least one photovoltaic power generation system is supplied to the DC power conversion device;
    A power storage device,
    An inverter that converts DC power into AC power,
    Equipped with an outlet,
    The at least one solar power generation system, the DC power converter, the inverter, and the outlet are connected in this order,
    The fuel cell power generation system, the characteristic conversion circuit, the DC power conversion device, the inverter, and the outlet are connected in this order,
    The power storage device, the inverter, and the outlet are connected in this order,
    The electric power system according to any one of claims 10 to 14.
  16. 　前記蓄電装置から前記燃料電池発電システムに電力を供給することができるように構成されている、
    　請求項１４または１５に記載の電力システム。
    　 
    　 
    　     It is configured to be able to supply electric power from the power storage device to the fuel cell power generation system,
    The electric power system according to claim 14 or 15.


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