JP5755191B2 - Inverter system - Google Patents

Description

  The present invention relates to a power conditioner system.

  Conventionally, a power conditioner converts DC power of a solar battery or a storage battery into AC power corresponding to the frequency and voltage of a system supplied from an electric power company to a consumer using an inverter, and is electrically connected to the system. While outputting power to the load in the house. In the event of a power failure in the system, the operation of the inverter is switched to independent operation by automatic or manual operation, and power is supplied to a specific residential load, enabling the use of electrical products even during a power failure. . A general residential power conditioner is equipped with a dedicated outlet for a self-sustained operation output that outputs a voltage of 100 VAC. The user can use the electric device even during a power failure by inserting the power plug of the electric device into the outlet.

  Specifically, Patent Document 1 below discloses a method for supplying power to a load during a self-sustaining operation. In a power converter (corresponding to a power conditioner), DC power generated by a solar cell is converted into AC power by an inverter in the power converter, and linked to a single-phase three-wire AC 200V system. In order to connect with the system of the system voltage 200V, the boost chopper boosts the voltage of the smoothing capacitor installed at the input of the inverter to a voltage of about 300V or more which is higher than the peak value of the system voltage. When some kind of failure occurs in the system, the interconnection connection between the power conversion apparatus and the system is cut off, and the power conversion apparatus is switched to a self-sustained operation. At this time, the inverter performs control so that the output voltage becomes 100 V AC, and supplies power to the load for independent operation.

Japanese Patent Laid-Open No. 9-135578 (FIG. 1)

  However, according to the above-described conventional technology, when the system is interrupted, the voltage that the power conditioner can output in the self-sustaining operation is only AC 100V. Therefore, there is a problem that the user can only use 100V equipment and cannot use 200V equipment.

  In addition, the load that can be used during autonomous operation is limited to a specific load, and in order to use the load that was used during grid connection during autonomous operation, the user must connect to the autonomous operation output of the inverter. is there. A general residential power conditioner is provided with a dedicated outlet that outputs a voltage of 100 VAC during stand-alone operation, but there is a problem that the user needs to connect an electrical product to this outlet. It was.

  Also, when using electric appliances that are difficult to carry, such as TVs, refrigerators, washing machines, etc., it is necessary to extend the power strip of the power conditioner from the dedicated outlet to the place where the power cord of the electric appliance reaches, There was a problem that it was not easy to use.

  The present invention has been made in view of the above, and is a power conditioner that can supply electric power of a plurality of voltages when a power failure occurs in a system and can continuously supply power to a load in use at the time of system interconnection. The purpose is to obtain a system.

  In order to solve the above-described problems and achieve the object, the present invention is a power conditioner system that supplies power to a load in conjunction with a system, which converts DC power into AC power, A power conditioner that outputs the AC power from an output terminal and a power conditioner that can be connected in parallel to the load during grid connection during power supply and during independent operation when the power supply is stopped The primary voltage input is the voltage of the AC power, the voltage of the AC power is divided and output as the secondary voltage, and the primary transformer which does not insulate the primary side and the secondary side. The power conditioner monitors the power supply state of the system, and while the system is supplying power, the power conditioner is connected to the system and is disconnected from the autotransformer, and the system stops power supply. Octopus When detecting, blocking the connection with the system, the autotransformer control means for performing control of connecting the output terminals, characterized in that it comprises a.

  According to the present invention, it is possible to supply power of a plurality of voltages when a system power failure occurs and to continuously supply power to a load in use at the time of system interconnection.

FIG. 1 is a diagram illustrating a configuration example of a conventional power conditioner system. FIG. 2 is a diagram illustrating a configuration example of the power conditioner system according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of the autotransformer. FIG. 4 is a diagram illustrating supply of electric power to a load in a house when the power conditioner according to Embodiment 1 is operated independently. FIG. 5 is a diagram illustrating a connection between the power conditioner and the autotransformer. FIG. 6 is a diagram illustrating a configuration example of a system in which a solar battery and a battery mounted on an electric vehicle are used in combination. FIG. 7 is a diagram illustrating a configuration example of a system in which a solar battery and a battery mounted on an electric vehicle are used in combination.

  Embodiments of a power conditioner system according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
First, the configuration of a conventional power conditioner system will be briefly described. FIG. 1 is a diagram illustrating a configuration example of a conventional power conditioner system. Shown in single-line diagram. The DC power generated by the solar cell 1 is converted into AC power by the inverter 5 in the power conditioner 2 ′, and the single-phase three-wire AC 200 V system 7 and the switch 6 are closed and connected. In order to connect with the system of the system voltage 200V, the step-up chopper 3 boosts the voltage of the smoothing capacitor 4 installed at the input of the inverter 5 to about 300V or higher which is higher than the peak value of the system voltage. When some trouble occurs in the system 7, the switch 6 is opened to cut off the interconnection between the power conditioner 2 'and the system 7, and the power conditioner 2' is switched to the independent operation. At this time, the inverter 5 performs control so that the output voltage becomes AC 100 V, closes the switch 8, and supplies power for autonomous operation to the load 9. Thus, only 100V AC is output during the independent operation.

  Next, the power conditioner system according to the present embodiment will be described. FIG. 2 is a diagram illustrating a configuration example of the power conditioner system according to the present embodiment. Shown in single-line diagram. The same components as those in FIG. The same applies thereafter.

  The power conditioner system includes a solar cell 1, a junction box 10, a power conditioner 2, a distribution board 14, a watt hour meter 19, a system 7, a load 9, an electromagnetic contactor 20, and a single volume. And a transformer 21. The power conditioner 2 includes an inverter 5, a connection switch 11, a control unit 12, and an output terminal 13. The distribution board 14 includes a power generation equipment dedicated breaker 15, a branch breaker 16, an electromagnetic contactor 17, and a contract breaker 18.

  In FIG. 2, DC power is input to the power conditioner 2 from a solar cell 1 that generates DC power through a connection box 10 that collects a plurality of parallel circuits of the solar cells 1 into one circuit. The power conditioner 2 converts the input DC power into AC power by the inverter 5, and converts the converted AC power via the connection switch 11 (an electromagnetic contactor or a relay is used) and the output terminal 13. And output to the breaker 15 dedicated to the power generation equipment in the distribution board 14. A 50 Hz or 60 Hz system 7 is connected to a contract breaker 18 of the distribution board 14 (which may not be installed depending on the electric power company) via a watt hour meter 19. Further, the distribution board 14 is provided with a branch breaker 16 for wiring to each outlet in order to supply electric power to the load 9 such as an electric device in the house. An electromagnetic contactor 17 capable of opening and closing an electrical connection with the system 7 is provided between the power generation equipment dedicated breaker 15 and the contract breaker 18.

  The contract breaker 18, the power generation equipment dedicated breaker 15, and the branch breaker 16 of the distribution board 14 are normally turned on. When the system 7 is normal, the control unit 12 of the power conditioner 2 receives the power receiving unit of the system 7. The voltage Vc (secondary side of the contract breaker 18 in FIG. 2) is detected, and the electromagnetic contactor 17 connected to the system 7 is turned on. If the amount of solar radiation is sufficient and the conditions under which the power conditioner 2 can be operated are prepared, normal grid-connected operation is performed, and the power conditioner 2 outputs a single-phase two-wire 200V electric method. Since the output from the power conditioner 2 is connected to a power receiving point that is drawn from the secondary side of the pole transformer by a single-phase three-wire system, power can be supplied to both 200V and 100V loads in the house. .

  When the power from the solar cell 1 is supplied to the load 9 and the power generation amount of the solar cell 1 is insufficient with respect to the power consumption of the load 9, the power is supplemented from the system 7, and the power consumption of the load 9 is small. When the generated power of the solar cell 1 is surplus, the surplus power is reversely flowed to the grid 7. The watt-hour meter 19 (only one is shown in FIG. 2) measures the purchased power from the system 7 and the sold power to the system 7, respectively. In addition, in the case where the input power to the power conditioner 2 is a battery mounted on a storage battery or an electric vehicle, since power cannot be sold to the grid 7, it is not shown in the figure. The excess power is prevented from flowing out to the grid 7 by the reverse power relay that detects.

  Here, when a power failure occurs in the system 7, the control unit 12 of the power conditioner 2 detects that the voltage Vc at the power receiving point (secondary side of the contract breaker 18 in FIG. 2) has disappeared, and automatically or manually Shifts to independent operation by operation. During self-sustained operation, the system interconnection regulation JEAC 9701-2010 stipulates that the output voltage of the inverter 2 is electrically disconnected so that the output voltage of the power conditioner 2 is not applied to the system 7. By opening the electromagnetic contactor 17, the electrical connection with the system 7 is completely cut off. In accordance with the grid connection regulations, two electromagnetic contactors 17 for disconnecting are installed.

  When shifting to the independent operation, the power conditioner 2 stops the power supply when the power is supplied by the grid connection, and before outputting (supplying) the electric power by the independent operation, the power conditioner 2 is connected via the magnetic contactor 20. Then, the output terminal 13 and the autotransformer 21 are connected. FIG. 3 is a diagram illustrating a configuration example of the autotransformer. As shown in FIG. 3, the autotransformer 21 has a configuration in which the primary side voltage is 200 V, two sets of 100 V can be output as the secondary side voltage, and the primary side and the secondary side are not insulated. The power conditioner 2 outputs a single-phase two-wire system 200V, which is the same electrical method as that at the time of grid connection, and supplies power to the load 9 through the wiring in the house as in the case of grid connection.

  FIG. 4 is a diagram illustrating the supply of electric power to the load in the house during the autonomous operation of the power conditioner according to the present embodiment. It is a double-line connection diagram, and only the configuration necessary for explanation is shown. Ordinary houses usually receive power from the secondary side of the columnar transformer from the secondary side of the column transformer so that both 200V equipment and 100V equipment can be used. Of the three wires, one wire is a grounded neutral wire 22, and three wires including the neutral wire 22 are connected to the output terminal 13 of the power conditioner 2. At the time of grid connection, the power conditioner 2 protects against overvoltage and undervoltage of the system 7 with respect to two 100V voltages with the neutral wire 22 as a reference.

  During the self-sustaining operation, the control unit 12 of the power conditioner 2 opens the electromagnetic contactor 17 in the distribution board 14, so that the electrical connection with the system 7 is cut off. In the power conditioner system, the interconnection switch 11, the power generation equipment dedicated breaker 15, the branch breaker 16, and the electromagnetic contactor 20 shown in FIG. During the independent operation, the power conditioner system outputs a single-phase two-wire voltage of 200 V, which is the same electrical system as when the power conditioner 2 is connected to the grid, and generates two 100 V voltages in the autotransformer 21. , Power can be supplied to both the 100V load 9a and the 200V load 9b.

  As described above, according to the present embodiment, the power conditioner 2 has the same electric system at any time during the grid interconnection operation in which the system 7 is normal and during the independent operation when the system 7 is out of power. A single-phase two-wire type 200V is output, and during self-sustained operation, two sets of primary side voltage 200V and secondary side voltage 100V can be output, and the primary transformer and the secondary side are not insulated. Connecting. The autotransformer 21 converts the AC 200V output from the power conditioner 2 into two sets of AC 100V voltages. As a result, power can be supplied to the 200V load 9b and the 100V load 9a via the distribution board 14, and power can be supplied from the power conditioner 2 to each load in the same way as during grid connection.

  In addition, since electric power can be supplied to the electrical product (load) connected to the wiring in the house even during independent operation, the home appliance is connected to the outlet for exclusive use of the independent operation output of the power conditioner as before. There is no need, and power can be supplied as it is to a device that is installed and used in a normally fixed place such as a television, a refrigerator, or a washing machine.

  In the present embodiment, the secondary neutral point of the autotransformer 21 is grounded. As a result, two sets of 100V voltages that are 180 degrees out of phase with respect to the ground are generated by the AC200V voltage output from the power conditioner 2 during self-sustained operation, and the ground voltage for indoor wiring is defined by the technical standards of electrical equipment. 150V or less, and the influence on the human body in the event of an electric shock can be reduced.

  Moreover, although the system for households was demonstrated, it is not limited to this. It is also possible for the power conditioner side to output AC power other than 200V, and to obtain an output other than 100V by voltage division with the autotransformer.

Embodiment 2. FIG.
In the present embodiment, when the system is switched to a self-sustaining operation by an automatic or manual operation at the time of a power failure, the power conditioner and the autotransformer are connected by a DC excitation mechanical latch type electromagnetic contactor. A different part from Embodiment 1 is demonstrated.

  FIG. 5 is a diagram illustrating a connection between the power conditioner and the autotransformer. Shown in a double-line diagram. Here, instead of the electromagnetic contactor 20, a DC excitation mechanical latch type electromagnetic contactor 20a is provided. When the system 7 fails and is switched to a self-sustained operation, the AC power supply by the system 7 is lost. Therefore, in the power conditioner 2, the electromagnetic contactor 20a is operated by control of the control part 12, and the output terminal 13 of the power conditioner 2 and the autotransformer 21 are connected. Here, by setting the electromagnetic contactor 20a to the DC excitation specification, the closing coil 23 can be excited by the DC power of the solar cell 1 and turned on. In addition, the tripping coil 24 can be turned off by being excited by the DC power of the solar cell 1 by adopting the same configuration.

  Thus, since the contact point of the magnetic contactor 20a is of the mechanical latch type specification, it is not necessary to continue supplying excitation power to the making coil 23 after the electromagnetic contactor 20a is turned on. Therefore, it is possible to save power consumption. Further, at the time of a power failure, the electromagnetic contactor 20a can be turned on by exciting the operating coil with a DC power supply such as the solar cell 1 in a situation where the electromagnetic contactor 20a cannot be turned on by the AC power from the system 7. .

Embodiment 3 FIG.
In the first and second embodiments, the power supply source during the self-sustaining operation is a solar cell, but the present invention is not limited to this. It goes without saying that the same effect can be obtained even if the power supply source is replaced with a storage battery or a battery of an electric vehicle that is expected to be widely used in the future. Furthermore, since the power supply becomes unstable depending on the amount of solar radiation with solar cells alone, the system is configured with a system that uses both a stationary storage battery and a battery for an electric vehicle as a power supply source. However, it is also assumed that the stability of power supply to home appliances during independent operation will increase.

  FIG. 6 is a diagram illustrating a configuration example of a system in which a solar battery and a battery mounted on an electric vehicle are used in combination. Shown in single-line diagram. In FIG. 6, the solar cell 1 and the storage battery 25 are installed in the power supply source, and the output is within the distribution board 14 a via the power conditioners 2 a and 2 b that change the respective DC power to AC power, and the dedicated breaker 15 a. , 15b. The distribution board 14 a is different from the distribution board 14 in that it includes two dedicated breakers and a current transformer 27.

  At the time of grid connection, each power conditioner 2a, 2b outputs a voltage synchronized with the frequency of the grid 7, and supplies power to the load 9. In addition, since the electric power of the storage battery 25 cannot flow into the system 7 (reverse power flow), the power conditioner 2b causes the reverse current to flow out to the system 7 by the current transformer 27 provided in the distribution board 14a. It is preventing.

  During the autonomous operation, the control unit 12b of the power conditioner 2b detects a power failure and opens the electromagnetic contactor 17 in the distribution board 14a. Next, the control unit 12b of the power conditioner 2b controls the electromagnetic contactor 20 to be connected to the autotransformer 21 and outputs a voltage of AC 200V. Moreover, the control part 12b of the power conditioner 2b uses the solar cell 1 as an electric power supply source, detects a power failure, and goes to independent operation via the communication line 26 with respect to the control part 12a of the power conditioner 2a in a stopped state. The power conditioner 2a is operated independently. During the self-sustained operation, control such as phase synchronization is required so that the voltages output from the power conditioners 2a and 2b do not adversely affect the operation, but details of the control are omitted.

  In addition, although the control part 12b of the power conditioner 2b which uses the storage battery 25 as an electric power supply source bears the system which transfers to a self-sustained operation here, it is not limited to this. For example, a control unit for controlling the entire system may be separately installed and the two power conditioners 2a and 2b may be controlled.

  In FIG. 6, the system is constructed with the power conditioners 2a and 2b, the electromagnetic contactor 20, and the autotransformer 21 as individual devices. However, these devices are configured to be housed in one casing. Is also possible. In particular, the use of the autotransformer 21 makes it possible to reduce the size and weight of the housing. FIG. 7 is a diagram illustrating a configuration example of a system in which a solar battery and a battery mounted on an electric vehicle are used in combination. Shown in single-line diagram. As shown in FIG. 7, if each device is housed in a housing 28 corresponding to outdoor installation, advantages such as ease of construction work occur.

  In addition, although the characteristic operation | movement was demonstrated separately in each embodiment, each embodiment can be combined freely and it can change and abbreviate | omit each embodiment suitably.

  As described above, the power conditioner system according to the present invention is useful for a system interconnected with a system, and is particularly suitable when the system has a power failure.

  DESCRIPTION OF SYMBOLS 1 Solar cell, 2, 2 ', 2a, 2b Power conditioner, 3 Boost chopper, 4 Smoothing capacitor, 5 Inverter, 6 Switch, 7 System, 8 Switch, 9 Load, 9a 100V load, 9b 200V load, 10 Junction box, 11 Switch for connection, 12 Control unit, 13 Output terminal, 14, 14a Distribution board, 15, 15a, 15b Breaker for power generation equipment, 16 Breaker for branching, 17 Magnetic contactor, 18 Contract breaker, 19 Watt-hour meter, 20, 20a magnetic contactor, 21 autotransformer, 22 neutral wire, 23 charging coil, 24 trip coil, 25 storage battery, 26 communication line, 27 current transformer, 28 housing.

Claims (5)

A power conditioner system that supplies power to a load in conjunction with a grid,
A power conditioner that converts direct current power into alternating current power and outputs the alternating current power from an output terminal at the time of grid connection when the grid is supplying power and when the grid is in a self-sustaining operation when power supply is stopped.
The load can be connected in parallel with the power conditioner, and the primary voltage input is the voltage of the AC power, the voltage of the AC power is divided and output as the secondary voltage, and the primary side And a self-winding transformer that does not insulate the secondary side,
With
The inverter is
The power supply state of the system is monitored, the output terminal is connected to the system while the system is supplying power, and the connection to the autotransformer is cut off, and the system stops power supply. when detecting, control means for controlling to connect the autotransformer with interrupting the connection to the system,
A power conditioner system comprising: The autotransformer grounds the neutral point of the secondary side,
The power conditioner system according to claim 1. As a contactor for connecting the output terminal and the primary side of the auto-transformer, a DC voltage excitation mechanical latch type electromagnetic contactor,
The power conditioner system according to claim 1, further comprising: When there are a plurality of DC power sources, the same number of the power conditioners as the DC power sources are provided, and the control means of one power conditioner that detects that the system has stopped supplying power is the control of another power conditioner. Command autonomous operation to the means,
The power conditioner system according to claim 1, 2, or 3. The power conditioner converts the DC power and outputs 200V AC power from the output terminal in a single-phase two-wire system 200V,
The autotransformer has a primary side voltage of 200V and outputs two sets of 100V as the secondary side voltage.
The power conditioner system according to any one of claims 1 to 4.

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