JP2008154334A - Power conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To utilize natural energy effectively by suppressing load variation when viewed from the system and suppressing system voltage variation beforehand in a power conditioner for use in solar battery or wind power generation thereby avoiding suppression of generated power. <P>SOLUTION: A power conditioner 11 including a charge control means 10 performing charging with an upper limit of a predetermined charging current to an electricity accumulation means 9 when generated power from a power generation means 1 exceeds the load power and surplus power is generated further includes an upper limit current alteration means 12 for controlling the depth of discharge not to saturate at an upper limit value or a lower limit value by altering the predetermined charging current depending on time series variation in depth of discharge of the electricity accumulation means 9. Consequently, the load when viewed from the system can be leveled even in case of the load power and generation power varying every day, and system voltage rise can be suppressed while utilizing generated power effectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power conditioner that controls electric power generated by a solar cell, wind power generation, and the like, and outputs the electric power connected to the grid side.

  In recent years, fossil fuel depletion and global warming have occurred due to an increase in the load on ordinary households, and the introduction of solar power generation systems using natural energy has been promoted. However, in ordinary houses, there are rare cases where there is load consumption commensurate with the generated power during the daytime solar power generation is possible, and as a result most of the generated power flows back to the grid side. Yes. In addition, as a regional initiative, efforts are being made to consider power supply and demand in a microgrid. Under such a social background, even if small-scale distributed power sources are concentrated and interconnected, the bus voltage will not rise, especially for photovoltaic power generation systems that have been promoted to spread. Therefore, there is a demand for a power conditioner that does not require any countermeasures on the grid side and prevents the voltage rise in the customer side system.

  Conventionally, this type of power conditioner does not store power temporarily, and when the system voltage rises, it reacts with reactive power control that outputs reactive power and reduces the voltage with the inductance component of the distribution line. What has the active power control which suppresses the active power currently output when voltage rise cannot be suppressed only by electric power control is known (for example, refer to patent documents 1). In addition, there is a known device that temporarily stores power when the voltage rises and supplies auxiliary power by discharging the stored power during a time period when load power is relatively high at night and when there is no generated power. (See Patent Document 2).

  Hereinafter, the power conditioner (solar power generation device 16) in Patent Document 1 will be described with reference to FIG.

  As shown in the figure, this solar power generation device 16 includes a power generation unit 17 and an inverter device 18 for grid connection. The inverter device 18 converts the DC power generated by the power generation unit 17 into AC power having a phase, frequency, and voltage corresponding to the single-phase three-wire commercial power system 19 and regenerates and outputs the AC power to the commercial power system 19. The inverter device 18 includes a booster circuit 20, an inverter circuit 21, a current smoothing circuit 22, and a controller 23, and usually converts the photovoltaic power generated by the power generation unit 17 in the booster circuit 20 to an optimum voltage as appropriate. ing. The DC power converted by the booster circuit 20 is input to the inverter circuit 21, and the DC power input from the booster circuit 20 corresponds to the commercial power system 19 by controlling the on / off of the switching element 24 by the controller 23. Converted to AC power. Inside the controller 23, the system voltage is monitored by the system voltage detection sensors 25 and 26, and when the system voltage rises, the target current value that is the target value of the output current is lowered.

  As a result, the output power from the inverter device 18 to the commercial power system 19 is gradually reduced. Further, since the suppression of output power continues when the system voltage does not decrease, the target current decreases below a predetermined value set in advance in the switching control unit 27, and finally the output of the switching signal is stopped.

  Hereinafter, the power conditioner (system interconnection type power supply system) in Patent Document 2 will be described with reference to FIG.

  As shown in the figure, power system power is supplied from the power system 28 to the load 29. A power supply system 32 is connected to the distribution board 31 of the wiring 30, and a power conditioner 34 of the photovoltaic power generation system is connected to the distribution board 33 of the wiring 30. The power conditioner 34 inputs the generated power of the solar cell 36 via the backflow prevention diode 35 and outputs the generated power of the solar cell 36 converted to alternating current to the power supply system 28. The generated power output from the power conditioner 34 is supplied to a load 29 connected to the power supply system 28, and when the generated power is larger than the load power and the voltage of the power supply system 28 does not exceed a predetermined threshold value, Sell power to the power system.

  The power conditioner 34 includes a DC / DC converter 37 for boosting the power generation voltage of the solar battery 36, a smoothing capacitor 38, and an AC / DC converter for converting DC power into AC power synchronized with the phase of the power system 28. 39, a switch 40 for connecting the power supply system 28 and the AC / DC converter 39, and a system voltage detecting transformer 41 for detecting the voltage of the power supply system 28. On the other hand, the power supply system 32 is linked to the power supply system 28 in the same manner as the power conditioner 34. The power supply system 32 includes a storage battery 42, a bidirectional DC / DC converter 43, a smoothing capacitor 44, a bidirectional AC / DC converter 45, a switch 46, a system voltage detection transformer 47, a power detection means 48, and a charge / discharge control means. 49, a voltage detection means 50, a threshold value discrimination means 51, and a display 52.

Further, the AC current detector 53 is provided on the downstream side of the connection point to the power conditioner 34 and the power supply system 28 of the power supply system 32. The power supply system 32 converts the power of the storage battery 42 into a bidirectional DC / DC converter 43, bidirectional AC / DC conversion so that the power of the power supply system 28 calculated by the alternating current detector 53 does not exceed a predetermined threshold. Discharge to the power supply system 28 via the device 45. At this time, when the solar cell 36 is generating power, the power conditioner 34 discharges the generated power to the power supply system 28 via the DC / DC converter 37 and the AC / DC converter 39. Further, when the generated power of the solar battery 36 is larger than the power consumed by the load 29, the power purchased from the power supply system 28 becomes zero, and the power conditioner 34 converts the generated power into a DC / DC converter 37, an AC / DC converter. The power supply system 28 is discharged via 39.
JP 2005-192317 A JP 2004-180467 A

  In such a conventional power supply device, a device that does not have a means for temporarily storing power has to output the generated power as it is, and it is necessary to suppress the output when the system voltage rises. Can not be used effectively, and solar cells and the like do not have power generated at night, so they receive power from the grid. Therefore, when viewed from the grid side, the power that is the sum of the absolute value of the reverse flow power during the daytime and the absolute value of the forward power flow during the night becomes the variable power. There are issues that require measures such as rising to suppress generated power, or adjusting the supply voltage on the grid side, and have an impact on the grid where distributed power sources are linked on the customer side. There is a demand for a system that makes effective use of generated power while avoiding it.

  In addition, although there is a system that temporarily stores power, for example, a self-supporting system that actively uses power storage means, an operation method corresponding to the load power of consumers that fluctuates from day to day is installed. It is assumed that the power storage means will be fully charged unless it has an infinite capacity during the intermediate period when the customer's load is light, and as a result, there is a high possibility of reaching output suppression control, If there is power generated after the full charge period, there are issues equivalent to those without power storage means, and it is possible to respond to changes in the load on the customer side, avoiding the impact on the system However, there is a demand for a system that makes effective use of generated power.

  The present invention solves such a conventional problem, predicts load power from the time series data of the amount of electricity temporarily stored power, performs charging and discharging to the optimal power storage means, The purpose is to provide a power conditioner that enables optimal operation of generated power.

  In addition, the present invention makes it possible to minimize the power fluctuation of the consumer load as viewed from the grid by optimal charge / discharge control, that is, it has an effect of leveling the load power and adjusts the supply voltage on the grid side. It is an object of the present invention to provide a power conditioner that can suppress the occurrence of an output suppression phenomenon in advance.

  In order to achieve the above object, the power conditioner of the present invention has a power generation means for generating power and a diode in reverse parallel to the switching element that outputs the generated power obtained by the power generation means to an AC power supply in series. A full-bridge inverter composed of two arms, a capacitor connected in parallel to the two arms, a main circuit control unit for controlling the full-bridge inverter, and connected in parallel to the capacitor according to the vertical fluctuation of the system voltage In a power conditioner comprising a power storage means for charging and discharging, and a charge control means for charging the power storage means with a predetermined charging current as an upper limit when the generated power of the power generation means exceeds load power and surplus power is generated. The predetermined charging current is changed according to the time-series fluctuation of the discharge depth of the power storage means, and the discharge depth reaches the upper limit value. There is obtained by the structure having the upper limit current changing means for controlling so as not to saturate the lower limit value.

  By this means, even if the load power and the generated power fluctuate every day depending on the house, it is possible to predict the load amount from the discharge depth of the power storage means and optimally control it, and flexibly surplus power Temporary storage, discharge is possible when necessary, and auxiliary supply is possible. In other words, it is possible to prevent the system voltage from rising by reducing fluctuations in system power (power sales, power purchase), etc. Even if the system voltage rises due to the influence of the power conditioner, a power conditioner capable of charging and discharging for effectively utilizing the generated power can be obtained.

  Further, the upper limit current changing means is configured to control by inputting the time series fluctuation of the load power.

  By this means, it is possible to obtain a power conditioner capable of effectively utilizing surplus power by performing charge / discharge control of the power storage means that can flexibly cope with the load power of a house that fluctuates daily.

  Further, the discharge current is limited in accordance with the time-series fluctuation of the discharge depth of the power storage means.

  By this means, it is possible to limit the auxiliary supply power according to the depth of discharge of the power storage means for the load fluctuation in the time zone when the generated power is low, and avoid the auxiliary supply concentrated in the time zone when the discharge is started. Since the auxiliary supply can be stably performed over the entire period of the less time zone, a power conditioner capable of obtaining the leveling effect of the system power can be obtained.

  Further, the discharge control from the power storage means is configured to start when the load power or the received power from the system exceeds a predetermined power.

  By this means, the load power viewed from the system can be suppressed to a predetermined power, and a power conditioner having a load leveling effect on the house can be obtained.

  Further, the predetermined power is changed according to the time-series fluctuation of the depth of discharge of the power storage means.

  By this means, it is possible to avoid discharging the electric power stored in the power storage means while concentrating on a part of the time zone where the generated power is low, and the load power viewed from the system can be suppressed to a predetermined power level. Thus, a power conditioner having an effect can be obtained.

  Further, the system voltage for starting charging is changed according to the time-series fluctuation of the depth of discharge of the power storage means.

  By this means, it is possible to avoid saturation of the discharge depth of the power storage means to the lower limit value (discharge depth closer to full charge), thereby avoiding concentration of charging power in a specific time zone. Thus, a power conditioner capable of further stabilizing the total value of the output of the generated power to the system side and the load power as seen from the system is obtained.

  Further, the system voltage for starting the discharge is changed according to the time-series fluctuation of the depth of discharge of the power storage means.

  By this means, it is possible to avoid the saturation of the discharge depth of the power storage means to the upper limit value (discharge depth with a small remaining capacity), it is possible to avoid the concentration of discharge power in a specific time zone, A power conditioner that can further stabilize the total value of the output of the generated power to the grid side and the load power as seen from the grid is obtained.

  Further, the system voltage for starting charging and the system voltage for starting discharging are configured to be different from each other.

  By this means, it is possible to avoid hunting of charge control and discharge control for the power storage means, and a power conditioner capable of further stabilizing charge / discharge control can be obtained.

  Furthermore, the system voltage for starting charging is configured to be higher than the system voltage for starting discharging.

  By this means, it is possible to obtain a power conditioner that can prevent charge control and discharge control from deviating from desired control and can further stabilize charge / discharge control.

  The charging start voltage is configured to be lower than the output suppression start voltage that suppresses the generated power of the power generation means when the system voltage rises.

  By this means, charging of the power storage means is started before the generated power is suppressed, so that a power conditioner capable of taking out power that can be generated is obtained.

  Further, the time-series fluctuation is configured to be a fluctuation of an average value or a moving average value for a predetermined period.

  By this means, it is possible to realize time series variation processing with a simpler control method, and to obtain a power conditioner that is excellent in versatility and can be realized at a lower cost.

  Further, the predetermined period is configured to be a day unit.

  By this means, it is possible to obtain a power conditioner that can enable fluctuation tracking according to the lifestyle pattern of the house.

  Further, the change of the charging current is configured such that the charging current value after the change is determined by the proportional-plus-integral control means having time series fluctuation as an input.

  By this means, the time constant can be increased and the load condition can be changed according to the season, so that a power conditioner capable of more stable charge / discharge control can be obtained.

  Further, when the discharge depth of the power storage means reaches a predetermined upper limit value or lower limit value, the limit value of the discharge current or the charging current is changed.

  By this means, it is possible to obtain a power conditioner that can perform an emergency process when the load changes suddenly due to a sudden change in the climate and can perform more stable charge / discharge control.

  Further, the upper limit current changing means is configured to input and control the fluctuation range of the received power from the system or the reverse flow power to the system.

  By this means, since the system power is directly monitored and controlled, charge / discharge control linked to the actual situation is possible, and a power conditioner capable of stabilizing the system voltage is obtained.

  According to the present invention, a full-bridge inverter constituted by two arms in which a power generation means for generating power and a diode in reverse parallel to a switching element are connected in series up and down outputs power generated by the power generation means to an AC power source. A capacitor connected in parallel to the two arms, a main circuit control unit for controlling a full bridge inverter, a power storage means connected in parallel to the capacitor to charge and discharge according to vertical fluctuations in system voltage, In a power conditioner comprising a charge control means for charging the power storage means with a predetermined charging current as an upper limit when the generated power of the power generation means exceeds the load power and surplus power is generated, at the time of the depth of discharge of the power storage means In addition to changing the predetermined charging current according to the series fluctuation, control is performed so that the depth of discharge does not saturate to the upper limit value or the lower limit value. By adopting a configuration with current changing means, it becomes possible to optimally control the depth of discharge of the power storage means even when the load power and generated power fluctuate every day depending on the house, and surplus power can be flexibly flexible Can be temporarily stored, discharged when necessary, and supplementary supply is possible, that is, by suppressing fluctuations in system power (power sales, power purchase), it is possible to prevent the system voltage from rising, Even when the system voltage rises due to other influences, it is possible to provide a power conditioner that has an effect of being able to charge and discharge to effectively use the generated power.

  In addition, the upper limit current changing means is configured to control by inputting time series fluctuation of load power, so that charge / discharge control of the power storage means that can flexibly cope with the load power of houses that fluctuates daily. Thus, it is possible to provide a power conditioner that is effective in effectively using surplus power.

  In addition, the configuration is such that the discharge current is limited according to the time-series fluctuation of the discharge depth of the power storage means, so that the load fluctuation in the time zone when the generated power is small is limited to the auxiliary power supply according to the discharge depth of the power storage means. Auxiliary supply concentrated in the time zone when the discharge is started can be avoided, and the auxiliary supply can be stably supplied in the whole period of the time zone where the generated power is low, so that the system power leveling effect is obtained. It is possible to provide a power conditioner that has the effect of being able to.

  In addition, the discharge control from the power storage means is configured to start when the load power or the received power from the system exceeds the predetermined power, thereby suppressing the load power viewed from the system to the predetermined power. It is possible to provide a power conditioner that is effective in obtaining a load leveling effect on a house.

  Furthermore, by setting the predetermined power to change according to the time-series fluctuation of the discharge depth of the power storage means, the charge power of the power storage means is discharged in a concentrated manner in a part of the time zone where the generated power is low. Thus, the load power viewed from the grid can be suppressed to a predetermined power, and a power conditioner having an effect of obtaining the load leveling effect of the house can be provided.

  In addition, by adopting a configuration in which the system voltage at which charging is started is changed in accordance with time-series fluctuations in the depth of discharge of the power storage means, the discharge depth of the power storage means is set to a lower limit (a discharge depth closer to full charge). Since it is possible to avoid saturation, it is possible to avoid the concentration of charging power in a specific time zone, and the total value of the output to the grid side of the generated power and the load power as seen from the grid is more stable Therefore, it is possible to provide a power conditioner having an effect of being able to be realized.

  Furthermore, the configuration is such that the system voltage at which discharge starts is changed according to the time-series fluctuation of the discharge depth of the storage means, so that the discharge depth of the storage means is saturated to the upper limit value (discharge depth with a small remaining capacity). Therefore, it is possible to avoid the concentration of discharge power during a specific time period, and to stabilize the total value of the output to the grid side of the generated power and the load power as seen from the grid It is possible to provide a power conditioner that has the effect of being able to.

  In addition, by configuring the system voltage for starting charging and the system voltage for starting discharging to be different from each other, it is possible to avoid hunting between charging control and discharging control for the power storage means, and charging / discharging control. Thus, it is possible to provide a power conditioner having an effect that it can be further stabilized.

  Furthermore, the system voltage for starting charging is configured to be higher than the system voltage for starting discharging, thereby preventing charge control and discharge control from deviating from desired control, and further charge / discharge control. It is possible to provide a power conditioner that has an effect of enabling stabilization.

  In addition, the charging start voltage is set to be lower than the output suppression start voltage that suppresses the generated power of the power generation means when the system voltage rises, so that the power storage means can be charged before the generated power is suppressed. Therefore, it is possible to provide a power conditioner that has an effect of being able to extract electric power that can be generated.

  Furthermore, the time-series fluctuation can be realized by a simpler control method by adopting a configuration in which the time-series fluctuation is a fluctuation of the average value or the moving average value of a predetermined period, and is excellent in versatility. Therefore, it is possible to provide a power conditioner that can be realized at a lower cost.

  Moreover, the power conditioner which has the effect that the tracking according to the life pattern of a house can be enabled can be provided by setting it as the unit which makes a predetermined period a day unit.

  In addition, the charging current can be changed by setting the charging current value after the change by proportional integral control means with time series fluctuation as input, so that the time constant can be increased, and the load amount according to the season Therefore, it is possible to provide a power conditioner having an effect of enabling more stable charge / discharge control.

  In addition, when the depth of discharge of the power storage means reaches a predetermined upper limit value or lower limit value, the load amount can be reduced by changing the discharge current or the charging current limit value so that the climate changes rapidly. It is possible to provide a power conditioner that has an effect of enabling emergency processing in the case of sudden change and enabling more stable charge and discharge control.

  Furthermore, the upper limit current changing means is configured to control the system power by directly monitoring the system power by inputting the fluctuation range of the received power from the system or the reverse power flow to the system. Therefore, it is possible to provide a power conditioner having an effect that the system voltage can be stabilized.

  The invention according to claim 1 of the present invention comprises power generation means for generating power, and two arms that are connected in series with a diode in reverse parallel to the switching element that outputs the generated power obtained by the power generation means to an AC power source. The constructed full bridge inverter, a capacitor connected in parallel to the two arms, a main circuit control unit for controlling the full bridge inverter, and connected in parallel to the capacitor are charged and discharged in accordance with fluctuations in the system voltage. In the power conditioner comprising a power storage means and a charge control means for charging the power storage means with a predetermined charging current as an upper limit when surplus power is generated when the generated power of the power generation means exceeds the load power, the power storage means The predetermined charging current is changed in accordance with the time-series fluctuation of the discharge depth, so that the discharge depth does not saturate to the upper limit value or the lower limit value. It is possible to optimally control the depth of discharge of the power storage means even when the load power and generated power fluctuate every day. , Flexible storage of surplus power temporarily, discharge when necessary, auxiliary supply possible, that is, by suppressing fluctuations in system power (selling power, purchasing power) to suppress system voltage rise In addition, even when the system voltage rises due to other influences, there is an effect that charging / discharging for effectively utilizing the generated power can be performed.

  Further, the upper limit current changing means is configured to input and control time series fluctuations of the load power, and charging / discharging of the power storage means that can flexibly cope with the load power of houses that fluctuates every day. Control has the effect that surplus power can be used effectively.

  Furthermore, it is configured to limit the discharge current according to the time-series fluctuation of the discharge depth of the power storage means, and the load fluctuation in the time zone when the generated power is small is changed to the auxiliary supply power according to the discharge depth of the power storage means. It is possible to avoid the auxiliary supply concentrated in the time zone when the discharge is started by applying restrictions, and the auxiliary supply can be stably provided in the whole period of the time zone when the generated power is low. It has the effect that it can be obtained.

  In addition, the discharge control from the power storage means is configured to start when the load power or the received power from the system exceeds a predetermined power, and suppresses the load power viewed from the system to the predetermined power. The load leveling effect of the house can be obtained.

  Furthermore, it is configured to change the predetermined power according to the time-series fluctuation of the discharge depth of the power storage means, and the charge power of the power storage means is discharged in a concentrated manner in a part of the time zone where the generated power is low. The load power viewed from the grid can be suppressed to a predetermined power, and the load leveling effect of the house can be obtained.

  Moreover, it is set as the structure which changes the system voltage which starts charge according to the time series fluctuation | variation of the depth of discharge of an electrical storage means, and the discharge depth of an electrical storage means is a lower limit (discharge depth nearer full charge). Therefore, it is possible to avoid charging power from concentrating in a specific time zone, and the total value of the output to the system side of the generated power and the load power as seen from the system can be further increased. It has the effect that it can be stabilized.

  Furthermore, the system voltage is changed so that the system voltage at which discharge starts is changed according to the time-series fluctuation of the discharge depth of the power storage means, and the discharge depth of the power storage means is set to the upper limit value (discharge depth with a small remaining capacity). Since it is possible to avoid saturation, it is possible to avoid the concentration of discharge power in a specific time zone, and the total value of the output to the grid side of the generated power and the load power as seen from the grid is more stable. It has the effect that it can be made.

  In addition, the system voltage for starting charging and the system voltage for starting discharging are configured to be different from each other, and it is possible to avoid hunting between charging control and discharging control for the power storage means, and charging / discharging. It has the effect that further stabilization of the control can be made possible.

  Furthermore, the system voltage at which charging is started is configured to be higher than the system voltage at which discharging is started, and charging control and discharging control are prevented from deviating from desired control, and charging / discharging control is further updated. It has the effect | action that it can be made possible.

  The charging start voltage is configured to be lower than the output suppression start voltage that suppresses the generated power of the power generation means when the system voltage rises. Therefore, it is possible to take out power that can be generated.

  Furthermore, the time series fluctuation is configured to be the average value of the predetermined period or the fluctuation of the moving average value, and the processing of the time series fluctuation can be realized with a simpler control method. It has an effect that it is excellent and can be realized at a lower cost.

  In addition, the predetermined period is configured to be a day unit, and has an effect that it is possible to perform fluctuation tracking according to the life pattern of the house.

  Furthermore, the change of the charging current is configured such that the charging current value after the change is determined by the proportional-integral control means using time series fluctuation as an input, and the time constant can be increased, and the load depending on the season Since it can respond to the fluctuation of the amount, it has an effect that more stable charge / discharge control can be realized.

  In addition, when the depth of discharge of the power storage means reaches a predetermined upper limit value or lower limit value, the discharge current or the limit value of the charging current is changed. This makes it possible to perform an emergency process when a sudden change occurs and to enable more stable charge / discharge control.

  Further, the upper limit current changing means is configured to input and control the fluctuation range of the received power from the system or the reverse power flow to the system, and the system power is directly monitored and controlled. Charge / discharge control linked to the actual situation is possible, and the system voltage can be stabilized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a configuration diagram of a power conditioner according to Embodiment 1 of the present invention. As shown in the figure, a solar cell 1a and a step-up chopper circuit 1b as power generation means 1, and switching elements 3a to 3a that output generated power obtained by raising the power from the solar cell 1a by the step-up chopper circuit 1b to the system power source 2. A full bridge inverter 6 composed of two arms 5a and 5b in which diodes 4a to 4d antiparallel to 3d are vertically connected in series, a capacitor 7 connected in parallel to the two arms 5a and 5b, and a full bridge inverter 6 And a main circuit control unit 8 for controlling the step-up chopper circuit 1b, and a storage battery 9a, a charge / discharge circuit 9b, and a charge / discharge control as a power storage means 9 connected in parallel to the capacitor 7 to charge / discharge according to the vertical fluctuation of the system voltage. When the generated power of the unit 9c and the power generation means 1 exceeds the load power and surplus power is generated, a predetermined charging current is supplied to the power storage means 9 In the power conditioner 11 including the charging control means 10 that charges as the upper limit, the predetermined charging current is changed according to the time-series fluctuation of the discharge depth of the power storage means 9, and the discharge depth does not saturate to the upper limit value or the lower limit value. Thus, the upper limit current changing means 12 is controlled.

  Next, a control flowchart of the charge / discharge control unit 9c will be described with reference to FIG.

  As shown in the figure, the charge / discharge control unit 9 c receives the charge current limit value from the charge control means 10. Further, when the system voltage Vac is input and the system voltage Vac exceeds the system upper limit voltage Vac_max (for example, 105 V), the output current command value of the power conditioner 11 is commanded to be lowered by ΔI. At this time, the output current command value is reduced to zero, and charging from the system power supply 2 is not performed. Further, the system upper limit voltage Vac_max is set to a voltage lower than a voltage Vac_limit (for example, 108 V) that suppresses the output of the power conditioner 11 due to an increase in the voltage of the system power supply 2. Due to this command, the supply and demand balance of the generated power is lost, and the voltage of the intermediate capacitor 7 increases. Next, the charge / discharge control unit 9 c inputs the voltage of the capacitor 7.

  It is determined whether or not the input voltage Vc of the capacitor 7 is higher than the charging threshold value Vch. The command value of the charging current is calculated by inputting to the PI controller from the deviation between the target value Vch * of the voltage of the capacitor 7 and the actual voltage value Vc. Here, if the charging current command value is larger than the chargeable current Ib_cha of the storage battery 9a, the charging current command value is limited to Ib_cha. Further, by limiting the charging current and reducing the output to the system power supply 2, the boost chopper circuit 1 b deviates from the MPPT control (maximum power tracking control) of the solar cell 1 a when the balance between supply and demand of generated power is lost. Limit control to constant power control will be performed. Next, when the received power from the system is input and the specified value Wg (for example, 500 W) is exceeded, the discharge control side discharges the power exceeding 500 W from the storage battery 9 a and supplies power. Further, when the system voltage Vac is lower than the system lower limit voltage Vac_min (for example, 98 V), the output current command value of the power conditioner 11 is commanded to be increased by ΔI. The command of the output current at this time is the limit control by selecting the smaller one of the maximum current Iinv_max that can be output from the power conditioner 11 or the current Iinv_100W at which the received power becomes a specified value Wg_min (for example, 100 W). To do.

  Due to this output current increase command, the supply and demand balance of the generated power is disrupted, so the voltage of the intermediate capacitor 7 decreases. Next, the charge / discharge control unit 9 c inputs the voltage of the capacitor 7. It is determined whether or not the input voltage Vc of the capacitor 7 is lower than the discharge threshold value Vcl. The discharge current command value is calculated by inputting it to the PI controller from the deviation between the target value Vcl * of the voltage of the capacitor 7 and the actual voltage value Vc, as in the case of charging. Furthermore, if the discharge current command value is larger than the dischargeable current Ib_dis of the storage battery 9a, the discharge current command value is limited to Ib_dis. Here, the system upper limit voltage Vac_max is a voltage value different from the system lower limit voltage Vac_min, and the system upper limit voltage Vac_max is a voltage value higher than the system lower limit voltage Vac_min.

  Next, a control flowchart of the charging control means 10 will be described with reference to FIG.

  As shown in the figure, the charging control means 10 sets Ia [A] (for example, 5 A) as the initial value of the charging current limit value. Further, whether or not the charging current limit value is updated from the upper limit current changing means 12 is input, and if there is an update, the deviation between the charging current limit value employed when the input is received and the updated charging current limit value is calculated. . Updating is performed by adding or subtracting with a soft start variable (for example, a change rate of 1 A / sec) according to the sign of the calculated result.

  Next, a control flowchart of the upper limit current changing unit 12 will be described with reference to FIG.

  As shown in FIG. 4, the upper limit current changing unit 12 inputs the depth of discharge DOD (t) of the power storage unit 9. The daily maximum value DODmax (day) and the minimum value DODmin (day) in the time series data are updated from the input discharge depth DOD (t). The update has seven maximum and minimum values for one week using a 24-hour timer. Furthermore, average values DODmax_ave and DODmin_ave of the maximum value and the minimum value for 7 days are calculated. On the 8th day, the oldest maximum value DODmax (7 days ago) and the minimum value DODmin (7 days ago) are rewritten and updated, and the latest 7 days maximum value and minimum value are stored. The deviation of the maximum value of the adjacent day is calculated from the determined weekly maximum value, and the deviation is input to the proportional-plus-integral controller 13A serving as the proportional-plus-integral control means. Further, the same process is performed for the minimum value, and it is input to the proportional-plus-integral controller 13B.

  In the proportional-plus-integral controller 13A, each target value DODmax (ref) of the maximum discharge depth value and the oldest discharge depth maximum value DODmax (7) one week ago are input, and the first proportional term and the first integral term are obtained. Calculate. Furthermore, each target value DODmax (ref) of the maximum discharge depth value and yesterday's maximum discharge depth value DODmax (1) are inputted, and the second proportional term and the second integral term are calculated. The first proportional term and the first integral term are for predicting and controlling the periodicity of household load, and the second proportional term and the second integral term are for predictive control with respect to other environments.

  The limit value of the discharge current is calculated by multiplying the calculated first and second terms by multiplying the load prediction gain and the environmental prediction gain by multiplying each of the first and second terms. The output from the proportional-integral controller 13A becomes a limit value of the discharge current. Further, when the limit value exceeds the allowable current value as compared with the allowable current value of the discharge current, the allowable current value is set as the limit value. In the proportional-plus-integral controller 13B, each target value DODmin (ref) of the discharge depth minimum value and the oldest discharge depth minimum value DODmin (7) one week ago are input, and the first proportional term and the first integral term are obtained. Calculate.

  Further, each target value DODmin (ref) of the minimum discharge depth value and yesterday's minimum discharge depth value DODmin (1) are inputted, and the second proportional term and the second integral term are calculated. The first proportional term and the first integral term are for predicting and controlling the periodicity of household load, and the second proportional term and the second integral term are for predictive control with respect to other environments. The output from the proportional-plus-integral controller 13B is a charging current limit value. As described above, the predetermined charging current (for example, 5 A) is changed to a current value (for example, 4.5 A) corresponding to the time-series fluctuation of the discharge depth.

  Further, when the limit value exceeds the allowable current value as compared with the allowable current value of the charging current, the allowable current value is set as the limit value. Further, when the current depth of discharge exceeds a predetermined upper limit value (for example, 70% discharge depth), the discharge current limit value is set to 0A, and when the current discharge depth is lower than a predetermined lower limit value (for example 0%), the charging current limit value is set. Set to 0A.

  The charging / discharging limit value calculated by the above processing is output to the charging control means 10.

  As described above, according to the first embodiment, the solar cell 1a and the step-up chopper circuit 1b as the power generation means 1, and the switching elements 3a to 3d that output the generated power obtained by the power generation means 1 to the system power source 2. A full-bridge inverter 6 composed of two arms 5a and 5b in which diodes 4a to 4d in antiparallel with each other are connected in series up and down, a capacitor 7 connected in parallel to the two arms 5a and 5b, and a full-bridge inverter 6 are controlled. Main circuit control unit 8 that is connected in parallel to capacitor 7 and performs charging / discharging according to the vertical fluctuation of the system voltage, and when the generated power of power generating unit 1 exceeds the load power and surplus power is generated In the power conditioner 11 provided with the charge control means 10 for charging the power storage means 9 with the predetermined charging current as the upper limit, the discharge depth of the power storage means 9 is adjusted. By changing the predetermined charging current according to the series variation and including the upper limit current changing means 12 for controlling the depth of discharge so as not to saturate the upper limit value or the lower limit value, the load varies depending on the house and further varies daily. Even when the power and generated power fluctuate daily, it is possible to optimally control the depth of discharge of the power storage means 9, flexibly store surplus power temporarily, and discharge it when necessary to provide auxiliary supply. In other words, by reducing fluctuations in system power (power sale, power purchase), it is possible to prevent the system voltage from rising, and to generate power even when the system voltage increases due to other effects. Charging / discharging for effective use of

  In this embodiment, the storage battery 9a is used as the storage medium of the storage means 9, but an electric double layer capacitor, a nickel hydrogen battery, a lithium ion battery, or the like may be used.

  Moreover, although the system | strain upper limit voltage was set to 105V and the system | strain lower limit voltage was set to 98V, another voltage may be sufficient.

  Furthermore, although the voltage Vac_limit for suppressing the output is 108 V, it may be changed depending on the region.

  Moreover, although the unit correction power of the received power is 5 W with respect to the deviation of 1% in the discharge depth, other power may be used depending on the capacity of the storage battery 9a and the equipment capacity.

  Furthermore, although the average settling value is 35%, other settling values may be used.

  In addition, the specified value Wg_min of the received power is set to 100 W, but may be other values in consideration of the load followability of the power conditioner 11.

  Furthermore, the soft start variable may be faster or slower than 1 A / sec.

  Moreover, although the predetermined upper limit value of the depth of discharge is set to 70%, it may be other values considering the deterioration of the storage battery 9a and the like, and the predetermined lower limit value is also set to 0%. Other values may be left.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 5 shows a configuration diagram of the power conditioner according to the second embodiment.

  As shown in the figure, the solar cell 1a and the boost chopper circuit 1b as the power generation means 1, and the switching elements 3a to 3a that output the generated power obtained by raising the power from the solar cell 1a by the boost chopper circuit 1b to the system power source 2. A full-bridge inverter 6 composed of two arms 5a and 5b in which diodes 4a to 4d antiparallel to 3d are connected in series vertically, a capacitor 7 connected in parallel to the two arms 5a and 5b, and a full-bridge inverter 6 A main circuit control unit 8 that controls the power supply, a storage battery 9a as a power storage means 9 that is connected in parallel to the capacitor 7 and performs charging / discharging according to the vertical fluctuation of the system voltage, a charging / discharging circuit 9b and a charging / discharging control unit 9cB, Charging that charges the storage means 9 with a predetermined charging current as an upper limit when the generated power of the means 1 exceeds the load power and surplus power is generated In the power conditioner 11 having the control means 10, an upper limit for controlling the depth of discharge not to saturate the upper limit value or the lower limit value by changing the predetermined charging current according to the time series fluctuation of the load power of the power storage means 9. The current changing unit 12B is provided.

  Next, a control flowchart of the charge / discharge control unit 9cB will be described with reference to FIG.

  As shown in the figure, the charge / discharge control unit 9cB inputs the charge current limit value from the charge control means 10. Further, when the system voltage Vac is input and the system voltage Vac exceeds the system upper limit voltage Vac_max (for example, 105 V), the output current command value of the power conditioner 11 is commanded to be lowered by ΔI. At this time, the output current command value is reduced to zero, and charging from the system power supply 2 is not performed. Further, the system upper limit voltage Vac_max is set to a voltage lower than a voltage Vac_limit (for example, 108 V) that suppresses the output of the power conditioner 11 due to an increase in the voltage of the system power supply 2. Due to this command, the supply and demand balance of the generated power is lost, and the voltage of the intermediate capacitor 7 increases. Next, the charge / discharge control unit 9cB inputs the voltage of the capacitor 7. It is determined whether or not the input voltage Vc of the capacitor 7 is higher than the charging threshold value Vch.

  The command value for the charging current is calculated by inputting to the PI controller from the deviation between the target value Vch * of the voltage of the capacitor 7 and the actual voltage value Vc. Here, if the charging current command value is larger than the chargeable current Ib_cha of the storage battery 9a, the charging current command value is limited to Ib_cha. Further, by limiting the charging current and reducing the output to the system power supply 2, the boost chopper circuit 1 b deviates from the MPPT control (maximum power follow-up control) of the solar cell 1 a when the supply and demand balance of generated power is lost. Limit control to constant power control will be performed. Next, the discharge control side receives the discharge current limit value from the upper limit current changing means 12B. When the received power from the system exceeds a specified value Wg_min (for example, 100 W), the power exceeding the discharge current limit value is discharged from the storage battery 9a to supply power. Further, when the system voltage Vac is lower than the system lower limit voltage Vac_min (for example, 98 V), the output current command value of the power conditioner 11 is commanded to be increased by ΔI.

  The command of the output current at this time is the limit control by selecting the smaller one of the maximum current Iinv_max that can be output from the power conditioner 11 or the current Iinv_100W at which the received power becomes a specified value Wg_min (for example, 100 W). To do. Due to this output current increase command, the supply and demand balance of the generated power is disrupted, so the voltage of the intermediate capacitor 7 decreases. Next, the charge / discharge control unit 9cB inputs the voltage of the capacitor 7. It is determined whether or not the input voltage Vc of the capacitor 7 is lower than the discharge threshold value Vcl. The command value of the discharge current is calculated by inputting to the PI controller from the deviation between the target value Vcl * of the voltage of the capacitor 7 and the actual voltage value Vc, as in the case of charging. Furthermore, if the discharge current command value is larger than the dischargeable current Ib_dis of the storage battery 9a, the discharge current command value is limited to Ib_dis. Here, the system upper limit voltage Vac_max is a voltage value different from the system lower limit voltage Vac_min, and the system upper limit voltage Vac_max is a voltage value higher than the system lower limit voltage Vac_min.

  Next, a control flowchart of the upper limit current changing unit 12B will be described with reference to FIG.

  As shown in the figure, the upper limit current changing unit 12B receives load power Lw (t). The maximum value Lwmax (day) and the minimum value Lwmin (day) for each day in the time series data are updated from the input load power Lw (t). Further, the load power Lw (t) is integrated to calculate the integrated load power Pw (Wh). The update always has seven integrated load powers for one week using a 24-hour timer.

  When the calculated average value Pw (t) _ave of the integrated load power exceeds the power generation facility capacity compared to the power generation facility capacity Ppv, the limit value of the upper limit current of the charging current is set to the allowable current value of the storage battery 9a as the upper limit. Increase and decrease the limit value of the upper limit current if it falls below the power generation capacity. The current deviation to be updated when increasing or decreasing is calculated as a correction current obtained by multiplying a unit correction current (for example, 1 A) per 1 kWh according to the deviation between the average value Pw (t) _ave of the integrated load power and the power generation equipment capacity Ppv. To do. The calculated correction current is added to the current optimum specified current value Ibat (t), and if it does not exceed the specified upper limit value of the storage battery 9a, it is updated. If it exceeds, the charge / discharge control unit is updated to the specified upper limit value. Output to 9cB. As described above, the predetermined charging current (for example, 5A) is added to the correction current (1A) corresponding to the fluctuation of the load power to update the predetermined charging current (for example, 6A).

  As described above, according to the second embodiment, the time series fluctuation of the load power is input, the charge / discharge control of the storage battery 9a is performed, and the received power corresponding to the load amount for each home and the power generation amount for each season. Setting can be made possible.

  In this embodiment, the storage battery 9a is used as the storage medium of the storage means 9, but an electric double layer capacitor, a nickel hydrogen battery, a lithium ion battery, or the like may be used.

  Moreover, although the system | strain upper limit voltage was set to 105V and the system | strain lower limit voltage was set to 98V, another voltage may be sufficient.

  Furthermore, although the voltage Vac_limit for suppressing the output is 108 V, it may be changed depending on the region.

  Moreover, although the unit correction power of the received power is 5 W with respect to the deviation of 1% in the discharge depth, other power may be used depending on the capacity of the storage battery 9a and the equipment capacity.

  Furthermore, although the unit correction current is 1 A per capacity deviation of 1 kWh, other current values may be used depending on the capacity of the storage battery 9a and the equipment capacity.

(Embodiment 3)
A third embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 8 shows a configuration diagram of the power conditioner according to the third embodiment.

  As shown in the figure, the solar cell 1a and the boost chopper circuit 1b as the power generation means 1, and the switching elements 3a to 3a that output the generated power obtained by raising the power from the solar cell 1a by the boost chopper circuit 1b to the system power source 2. A full-bridge inverter 6 composed of two arms 5a and 5b in which diodes 4a to 4d antiparallel to 3d are connected in series vertically, a capacitor 7 connected in parallel to the two arms 5a and 5b, and a full-bridge inverter 6 A main circuit control unit 8 that controls the battery, a storage battery 9a as a power storage means 9 that is connected in parallel to the capacitor 7 and performs charging / discharging according to the vertical fluctuation of the system voltage, a charging / discharging circuit 9b and a charging / discharging control unit 9cC, Charging that charges the storage means 9 with a predetermined charging current as an upper limit when the generated power of the means 1 exceeds the load power and surplus power is generated In the power conditioner 11 having the control means 10, an upper limit for controlling the predetermined depth of charging so as not to saturate the upper limit value or the lower limit value by changing the predetermined charging current according to the time series fluctuation of the discharge depth of the power storage means 9. The current changing unit 12 and the predetermined power changing unit 14 that changes the predetermined value of the received power from the system power supply 2 in accordance with the time-series fluctuation of the depth of discharge of the power storage unit 9 are provided.

  Next, a control flowchart of the charge / discharge control unit 9cC will be described with reference to FIG.

  As shown in the figure, the charge / discharge control unit 9cC inputs the charge current limit value from the charge control means 10. Further, when the system voltage Vac is input and the system voltage Vac exceeds the system upper limit voltage Vac_max (for example, 105 V), the output current command value of the power conditioner 11 is commanded to be decreased by ΔI. At this time, the output current command value is reduced to zero, and charging from the system power supply 2 is not performed. Further, the system upper limit voltage Vac_max is set to a voltage lower than a voltage Vac_limit (for example, 108 V) that suppresses the output of the power conditioner 11 due to an increase in the voltage of the system power supply 2. Due to this command, the balance between the supply and demand of the generated power is lost, and the voltage of the intermediate capacitor 7 increases. Next, the charge / discharge control unit 9 c inputs the voltage of the capacitor 7. It is determined whether or not the input voltage Vc of the capacitor 7 is higher than the charging threshold value Vch. The command value of the charging current is calculated by inputting to the PI controller from the deviation between the target voltage Vch * of the capacitor 7 and the actual voltage value Vc.

  Here, if the charging current command value is larger than the chargeable current Ib_cha of the storage battery 9a, the charging current command value is limited to Ib_cha. Further, by limiting the charging current and reducing the output to the system power supply 2, the boost chopper circuit 1 b deviates from the MPPT control (maximum power tracking control) of the solar cell 1 a when the balance between supply and demand of generated power is lost. Limit control to constant power control will be performed. Next, the discharge control side receives a predetermined power value of received power for starting discharge from the predetermined power changing means 14, that is, an optimum specified value Wgc (initial value is 500 W). When the received power Wt from the system exceeds the optimum specified value Wgc, the excess power is discharged from the storage battery 9a to supply power.

  Further, when the system voltage Vac is lower than the system lower limit voltage Vac_min (for example, 98 V), the output current command value of the power conditioner 11 is commanded to be increased by ΔI. The command of the output current at this time is the limit control by selecting the smaller one of the maximum current Iinv_max that can be output from the power conditioner 11 or the current Iinv_100W at which the received power becomes a specified value Wg_min (for example, 100 W). To do. Due to this output current increase command, the supply and demand balance of the generated power is disrupted, so the voltage of the intermediate capacitor 7 decreases. Next, the charge / discharge control unit 9 c inputs the voltage of the capacitor 7.

  It is determined whether or not the input voltage Vc of the capacitor 7 is lower than the discharge threshold value Vcl. The discharge current command value is calculated by inputting it to the PI controller from the deviation between the target value Vcl * of the voltage of the capacitor 7 and the actual voltage value Vc, as in the case of charging. Furthermore, if the discharge current command value is larger than the dischargeable current Ib_dis of the storage battery 9a, the discharge current command value is limited to Ib_dis. Here, the system upper limit voltage Vac_max is a voltage value different from the system lower limit voltage Vac_min, and the system upper limit voltage Vac_max is a voltage value higher than the system lower limit voltage Vac_min.

  Next, a control flowchart of the predetermined power changing unit 14 will be described with reference to FIG.

  As shown in the figure, the predetermined power changing unit 14 inputs the depth of discharge DOD (t) of the power storage unit 9. An average discharge depth DOD_ave (day) for each day in the time series data is calculated from the input discharge depth DOD (t). The update always has an average value of 7 for a week using a 24-hour timer. The calculated average value DOD (t) _ave of the discharge depth is per 1% according to the deviation (%) from the average discharge depth value DOD (t) _ave compared to the average value set value (for example, 35%) DOD_ave_ref. The correction power multiplied by the unit correction power (for example, 5 W) is calculated. The calculated corrected power is added to the current optimum specified value Wgc (t) to be updated and output to the charge / discharge control unit 9cC.

  As described above, according to the third embodiment, the predetermined value of the received power from the system power supply 2 is changed according to the time-series fluctuation of the discharge depth of the storage battery 9a, and the load amount for each home is updated. It is possible to set the received power according to the amount of power generated for each season.

  In this embodiment, the storage battery 9a is used as the storage medium of the storage means 9, but an electric double layer capacitor, a nickel hydrogen battery, a lithium ion battery, or the like may be used.

  Moreover, although the system | strain upper limit voltage was set to 105V and the system | strain lower limit voltage was set to 98V, another voltage may be sufficient.

  Furthermore, although the voltage Vac_limit for suppressing the output is 108 V, it may be changed depending on the region.

  Moreover, although the unit correction power of the received power is 5 W with respect to the deviation of 1% in the discharge depth, other power may be used depending on the capacity of the storage battery 9a and the equipment capacity.

  Furthermore, although the average settling value is 35%, other settling values may be used.

(Embodiment 4)
A fourth embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first to third embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 11 shows a configuration diagram of a power conditioner according to the fourth embodiment.

  As shown in the figure, the solar cell 1a and the boost chopper circuit 1b as the power generation means 1, and the switching elements 3a to 3a that output the generated power obtained by raising the power from the solar cell 1a by the boost chopper circuit 1b to the system power source 2. A full-bridge inverter 6 composed of two arms 5a and 5b in which diodes 4a to 4d antiparallel to 3d are connected in series vertically, a capacitor 7 connected in parallel to the two arms 5a and 5b, and a full-bridge inverter 6 A main circuit control unit 8 that controls the battery, a storage battery 9a as a power storage means 9 that is connected in parallel to the capacitor 7 and performs charging / discharging according to the vertical fluctuation of the system voltage, a charging / discharging circuit 9b and a charging / discharging control unit 9cD, Charging that charges the storage means 9 with a predetermined charging current as an upper limit when the generated power of the means 1 exceeds the load power and surplus power is generated In the power conditioner 11 having the control means 10, the voltage value of the system power supply 2 that starts charging and discharging is changed according to the time series fluctuation of the discharge depth of the power storage means 9, and the discharge depth is saturated to the upper limit value or the lower limit value. It is set as the structure provided with the upper limit electric current change means 12C controlled so that it may not.

  Next, a control flowchart of the charge / discharge control unit 9cD will be described with reference to FIG.

  As shown in the figure, the charge / discharge control unit 9cD inputs the charge current limit value from the charge control means 10. Further, when the system voltage Vac is inputted and the system voltage Vac exceeds the system upper limit voltage Vac_max (t) (initial value 105V) received from the upper limit current changing means 12C, the output current command value of the power conditioner 11 is set to only ΔI. Command to lower. At this time, the output current command value is reduced to zero, and charging from the system power supply 2 is not performed. Further, the system upper limit voltage Vac_max (t) is set to a voltage lower than a voltage Vac_limit (for example, 108 V) that suppresses the output of the power conditioner 11 due to an increase in the voltage of the system power supply 2. Due to this command, the supply and demand balance of the generated power is lost, and the voltage of the intermediate capacitor 7 increases.

  Next, the charge / discharge control unit 9cD inputs the voltage of the capacitor 7. It is determined whether or not the input voltage Vc of the capacitor 7 is higher than the charging threshold value Vch. The command value of the charging current is calculated by inputting to the PI controller from the deviation between the target value Vch * of the voltage of the capacitor 7 and the actual voltage value Vc. Here, if the charging current command value is larger than the chargeable current Ib_cha of the storage battery 9a, the charging current command value is limited to Ib_cha. Further, by limiting the charging current and reducing the output to the system power supply 2, the boost chopper circuit 1 b deviates from the MPPT control (maximum power tracking control) of the solar cell 1 a when the balance between supply and demand of generated power is lost. Limit control to constant power control will be performed. Next, when the power received from the system exceeds a specified value Wg (for example, 500 W), the discharge control side discharges the power exceeding 500 W from the storage battery 9 a and supplies power.

  Further, when the system voltage Vac is lower than the system lower limit voltage Vac_min (t) (initial value 98V) received from the upper limit current changing means 12C, the output current command value of the power conditioner 11 is commanded to be increased by ΔI. The command of the output current at this time is the limit control by selecting the smaller one of the maximum current Iinv_max that can be output from the power conditioner 11 or the current Iinv_100W at which the received power becomes a specified value Wg_min (for example, 100 W). To do. Due to this output current increase command, the supply and demand balance of the generated power is disrupted, so the voltage of the intermediate capacitor 7 decreases. Next, the charge / discharge control unit 9cD inputs the voltage of the capacitor 7. It is determined whether or not the input voltage Vc of the capacitor 7 is lower than the discharge threshold value Vcl.

  The discharge current command value is calculated by inputting it to the PI controller from the deviation between the target value Vcl * of the voltage of the capacitor 7 and the actual voltage value Vc, as in the case of charging. Furthermore, if the discharge current command value is larger than the dischargeable current Ib_dis of the storage battery 9a, the discharge current command value is limited to Ib_dis. Here, the system upper limit voltage Vac_max (t) is a voltage value different from the system lower limit voltage Vac_min (t), and the system upper limit voltage Vac_max (t) is a voltage value higher than the system lower limit voltage Vac_min (t).

  Next, a control flowchart of the upper limit current changing unit 12C will be described with reference to FIG.

  As shown in the figure, the upper limit current changing unit 12C inputs the depth of discharge DOD (t) of the power storage unit 9. An average discharge depth DOD_ave (day) for each day in the time series data is calculated from the input discharge depth DOD (t). The update always has an average value of 7 for a week using a 24-hour timer. The average value DOD_ave_week of the discharge depth DOD_ave (day) for one week accumulated by calculation is the system voltage at which charging starts if the average value set value (for example, 35%) DOD_ave_ref is subtracted and the deviation (%) is negative Is multiplied by a unit correction voltage per 1% (for example, -0.01 V). The calculated correction voltage is added to the current optimum upper limit voltage Vac_max (t), and the upper limit voltage exceeds 1 V lower than the voltage Vac_limit that suppresses the output of the power conditioner 11 due to the voltage increase of the system power supply 2. If not, it is updated, and if it exceeds 1V lower voltage than the voltage to suppress the output, it is updated to 1V lower voltage.

  In addition, the system voltage Vac_min (t) at which the discharge is started can be started when the average value DOD_ave_weak of the calculated discharge depth is compared with the average value set value (for example, 35%) DOD_ave_ref and the deviation (%) is positive. A correction voltage is calculated by multiplying the system voltage to be multiplied by a unit correction voltage per 1% (for example, -0.01 V). The calculated correction voltage is added to the current optimum lower limit voltage Vac_min (t), and if the lower limit voltage is not lower than the voltage management range (for example, 95 V) of the system power supply 2, the voltage is updated. If the voltage is 1V lower than the voltage, the voltage is updated to 1V higher. Further, the updated upper limit voltage and lower limit voltage are output to the charge / discharge control unit 9cD.

  As described above, according to the fourth embodiment, the system voltage at which charging / discharging of the storage battery 9a is started is changed according to the time-series fluctuation of the discharge depth of the storage battery 9a, and the system voltage is independently maintained and managed. However, operation that avoids output suppression is possible.

  In this embodiment, the storage battery 9a is used as the storage medium of the storage means 9, but an electric double layer capacitor, a nickel hydrogen battery, a lithium ion battery, or the like may be used.

  Moreover, although the initial value of the system upper limit voltage is 105 V and the initial value of the system lower limit voltage is 98 V, other voltages may be used.

  Furthermore, although the voltage Vac_limit for suppressing the output is 108 V, it may be changed depending on the region.

  Further, although the voltage management range of the system power supply 2 is 95 V, it may be a voltage that takes into account the impedance of the transmission line and the like.

  Further, although the unit correction voltage is set to -0.01V, it may be a unit correction voltage in consideration of the impedance of the transmission line.

  Moreover, although the average value set value is 35%, other set values may be used.

(Embodiment 5)
A fifth embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first to fourth embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 14 shows a configuration diagram of the power conditioner in the fifth embodiment.

  As shown in the figure, the solar cell 1a and the boost chopper circuit 1b as the power generation means 1, and the switching elements 3a to 3a that output the generated power obtained by raising the power from the solar cell 1a by the boost chopper circuit 1b to the system power source 2. A full-bridge inverter 6 composed of two arms 5a and 5b in which diodes 4a to 4d antiparallel to 3d are connected in series vertically, a capacitor 7 connected in parallel to the two arms 5a and 5b, and a full-bridge inverter 6 A main circuit control unit 8 that controls the battery, a storage battery 9a as a power storage means 9 that is connected in parallel to the capacitor 7 and performs charging / discharging according to the vertical fluctuation of the system voltage, a charging / discharging circuit 9b and a charging / discharging control unit 9cE, Charging that charges the storage means 9 with a predetermined charging current as an upper limit when the generated power of the means 1 exceeds the load power and surplus power is generated In the power conditioner 11 provided with the control means 10, the power receiving state output means 15 for outputting each fluctuation width of the received power from the system power supply 2 and the reverse flow power to the system power supply 2 to the upper limit current changing means 12D, and the power receiving state While controlling the received power fluctuation of the grid power supply 2 to be suppressed by inputting the fluctuation width of the received power and the reverse power flow from the output means 15, the discharge depth is changed according to the time series fluctuation of the discharge depth of the power storage means 9. It is configured to include upper limit current changing means 12D for controlling so as not to saturate the upper limit value or the lower limit value.

  Next, a control flowchart of the power reception state output unit 15 will be described with reference to FIG.

  As shown in the figure, the power receiving state output means 15 inputs the measured power at the power receiving point, and determines the received power or the reverse power flow from the sign. After the determination of the received power or the reverse flow power, the maximum or minimum value (the maximum value of the reverse flow power) of the received power for each day is updated with each input power. Also, an integrated value is calculated with the received power as a positive value and the reverse power flow as a negative value. Further, the average value is calculated by dividing the integrated value by the number of input values. The calculated power and average value are output to the upper limit current changing means 12D.

  Next, a control flowchart of the upper limit current changing unit 12D will be described with reference to FIG.

  As shown in the figure, the upper limit current changing unit 12 </ b> C inputs the maximum value and the average value of the received power from the system and the reverse flow power to the system power supply 2 from the power reception state output unit 15. Further, the voltage of the storage battery 9a at that time is input. Each deviation between the input average value and each maximum value on the power reception side and the reverse power flow side is calculated. Next, the upper limit value of the charging / discharging power exceeds each specified power value as compared with the specified charging power (for example, 3 kW) and the specified discharging power (for example, 4 kW) that can be input and output from the storage battery 9a from the calculated deviation. In this case, the specified power value is adopted, and when it does not exceed, the deviation is adopted.

  The upper limit value of the calculated and determined charge / discharge power is divided by the voltage of the input storage battery 9a to calculate each maximum charge / discharge current. Here, when each maximum current value becomes a value exceeding the chargeable current Ib_cha or the dischargeable current Ib_dis of the storage battery 9a, it is limited by each possible current value. Moreover, an average value is output to the charging / discharging control part 9cE with each maximum value as an electric power value which does not perform charging / discharging.

  Next, a control flowchart of the charge / discharge control unit 9cE will be described with reference to FIG.

  As shown in the figure, the charge / discharge control unit 9cE inputs the maximum current value and the average value of power from the upper limit current changing unit 12D. Since the average value of the power indicates the balance point of the received power, the battery operates so as to be discharged from the storage battery 9a when the received power exceeds the balance point, and to be charged when it falls below the balance point. Further, the calculated maximum current value is set as a charge / discharge current limit value. Moreover, subsequent control is implemented by the received power from a system | strain inputting the balance point of a receiving point into the regulation value Wg. Since the subsequent processing is the same as that of the charge / discharge control unit 9c in the first embodiment, detailed description thereof is omitted.

  As described above, according to the fifth embodiment, control is performed by inputting the fluctuation range of the received power or the reverse power flow from the system power supply 2, and the time change of the power reception or reverse power flow of the system power supply 2 is severe. Even in this case, the system power supply 2 can be stabilized by adjusting to the optimum parameters.

  In this embodiment, the storage battery 9a is used as the storage medium of the storage means 9, but an electric double layer capacitor, a nickel hydrogen battery, a lithium ion battery, or the like may be used.

  Further, the specified charging power and discharging power are 3 kW and 4 kW, respectively, but other limit values may be used depending on the facility capacity of the storage battery 9a.

  Since the power generation means using solar cells and fuel cells can be easily connected to the capacitor in parallel, the generated power can be easily peak shifted using the power storage means. It can also be applied to household use that requires

Configuration diagram of a power conditioner according to Embodiment 1 of the present invention Control flowchart of the charge / discharge control unit 9c Control flow chart of the charging control means 10 Control flow chart of the upper limit current changing means 12 Configuration diagram of a power conditioner according to Embodiment 2 of the present invention Control flowchart of the charge / discharge control unit 9cB Control flow chart of the upper limit current changing means 12B Configuration diagram of a power conditioner according to Embodiment 3 of the present invention Control flow chart of the charge / discharge control unit 9cC Control flowchart of the predetermined power changing means 14 Configuration diagram of a power conditioner according to Embodiment 4 of the present invention Control flow chart of charge / discharge control unit 9cD Control flow chart of the upper limit current changing means 12C Configuration diagram of a power conditioner according to Embodiment 5 of the present invention Control flow chart of the power reception state output means 15 Control flow chart of the upper limit current changing means 12D Control flowchart of the charge / discharge control unit 9cE Configuration diagram of conventional power conditioner in Patent Document 1 The block diagram of the power conditioner which has the conventional storage battery in patent document 2

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power generation means 1a Solar cell 1b Boost chopper circuit 2 System power supply 3a Switching element 3b Switching element 3c Switching element 3d Switching element 4a Diode 4b Diode 4c Diode 4d Diode 5a Arm 5b Arm 6 Full bridge inverter 7 Capacitor 8 Main circuit control part 9 Electric storage Means 9a Storage battery 9b Charge / discharge circuit 9c Charge / discharge control part 9cB Charge / discharge control part 9cC Charge / discharge control part 9cD Charge / discharge control part 9cE Charge / discharge control part 10 Charge control means 11 Power conditioner 12 Upper limit current change means 12B Upper limit current change means 12C Upper limit current changing means 12D Upper limit current changing means 13A Proportional integral controller 13B Proportional integral controller 14 Predetermined power changing means 15 Power receiving state output means

Claims (15)

A full-bridge inverter configured by two arms in which a diode in reverse parallel to a switching element that outputs generated power generated by the power generation means to an AC power supply is connected in series up and down; and the two arms A capacitor connected in parallel, a main circuit control unit that controls the full bridge inverter, a power storage means that is connected in parallel to the capacitor and charges and discharges according to fluctuations in the system voltage, and the generated power of the power generation means is loaded. In a power conditioner comprising a charge control means for charging the power storage means with a predetermined charging current as an upper limit when surplus power is generated in excess of the electric power, the predetermined power supply according to a time-series variation in the discharge depth of the power storage means Upper limit current changing means for changing the charging current so as to prevent the depth of discharge from saturating to the upper limit value or the lower limit value is provided. Power conditioner, characterized in that. 2. The power conditioner according to claim 1, wherein the upper limit current changing means is controlled by inputting time series fluctuations of the load power. The power conditioner according to claim 1, wherein the discharge current is limited in accordance with a time-series variation in the depth of discharge of the power storage means. 2. The power conditioner according to claim 1, wherein the discharge control from the power storage means starts when the load power or the received power from the system exceeds a predetermined power. The power conditioner according to claim 4, wherein the predetermined power is changed according to a time-series fluctuation of the depth of discharge of the power storage means. 2. The power conditioner according to claim 1, wherein the system voltage for starting charging is changed in accordance with time-series fluctuations in the depth of discharge of the power storage means. 2. The power conditioner according to claim 1, wherein the system voltage at which discharge is started is changed in accordance with time-series fluctuations in the depth of discharge of the power storage means. 2. The power conditioner according to claim 1, wherein the system voltage for starting charging and the system voltage for starting discharging are different from each other. The power conditioner according to claim 1, wherein the system voltage for starting charging is higher than the system voltage for starting discharging. 2. The power conditioner according to claim 1, wherein the charging start voltage is lower than the output suppression start voltage that suppresses the generated power of the power generation means when the system voltage increases. The power conditioner according to any one of claims 1 to 10, wherein the time series fluctuation is a fluctuation of an average value or a moving average value in a predetermined period. The power conditioner according to claim 10, wherein the predetermined period is in units of days. 2. The power conditioner according to claim 1, wherein the charging current is changed by determining the changed charging current value by means of proportional-integral control means having time series fluctuations as an input. The power conditioner according to claim 1, wherein when the depth of discharge of the power storage means reaches a predetermined upper limit value or lower limit value, the limit value of the discharge current or the charging current is changed. 2. The power conditioner according to claim 1, wherein the upper limit current changing means is controlled by inputting a fluctuation range of the received power from the system or the reverse flow power to the system.

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