WO2022208809A1 - Power conversion system - Google Patents

Power conversion system Download PDF

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Publication number
WO2022208809A1
WO2022208809A1 PCT/JP2021/014039 JP2021014039W WO2022208809A1 WO 2022208809 A1 WO2022208809 A1 WO 2022208809A1 JP 2021014039 W JP2021014039 W JP 2021014039W WO 2022208809 A1 WO2022208809 A1 WO 2022208809A1
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Prior art keywords
inverter device
multiple inverter
phase
conversion system
power generation
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PCT/JP2021/014039
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French (fr)
Japanese (ja)
Inventor
一誠 深澤
雅博 木下
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東芝三菱電機産業システム株式会社
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Priority to PCT/JP2021/014039 priority Critical patent/WO2022208809A1/en
Publication of WO2022208809A1 publication Critical patent/WO2022208809A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/493—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode the static converters being arranged for operation in parallel

Definitions

  • the present disclosure relates to a power conversion system, and more particularly to a power conversion system suitable for use in a photovoltaic power generation system.
  • Patent Document 1 discloses a multiple inverter device that converts the DC voltage from the first and second DC capacitors into a three-phase AC voltage.
  • This multiple inverter device consists of a plurality of units connected in parallel to the first and second DC capacitors. Each unit is composed of an open delta-connected transformer with a secondary winding connected to an AC circuit, and first and second inverters (three-phase inverters).
  • the first inverter has an input terminal connected to the first DC capacitor and an output terminal connected to one end of the primary winding of the open delta transformer.
  • the second inverter has an input terminal connected to the second DC capacitor and an output terminal connected to the other end of the primary winding of the open delta transformer.
  • Each unit is connected to a common AC circuit through an open delta transformer.
  • the output capacity can be increased by multiplexing the inverters.
  • the use of the multiplexed inverter device described in Patent Document 1 will increase the cost of the photovoltaic power generation system.
  • the present disclosure has been made in view of the problems described above, and includes a power conversion system that converts DC power supplied from a photovoltaic power generation facility into three-phase AC power, and includes a single open delta connection transformer.
  • the purpose is to make it possible to increase the output capacity by using
  • a power conversion system is a system that converts DC power supplied from a photovoltaic power generation facility into three-phase AC power, and includes a single open delta connection transformer connected to an AC power system and a first A multiple inverter device and a second multiple inverter device are provided.
  • the first multiple inverter device and the second multiple inverter device both have a plurality of three-phase inverters connected in parallel, and are configured by connecting DC capacitors in parallel to the input terminals of the plurality of three-phase inverters. .
  • the photovoltaic power generation facility has a first photovoltaic power generation facility in which a plurality of solar cell groups are connected in parallel, and a second photovoltaic power generation facility in which a plurality of solar cell groups are connected in parallel.
  • a first multiple inverter arrangement has an input connected to the first photovoltaic power plant and an output connected to one end of the primary winding of each phase of the open delta connected transformer.
  • a second multiple inverter arrangement has an input connected to the second photovoltaic power plant and an output connected to the other end of the primary winding of each phase of the open delta connected transformer.
  • both the first multiple inverter device and the second multiple inverter device are configured by connecting the output terminals of a plurality of three-phase inverters to each other via an AC reactor for each common phase.
  • a DC switch may be provided between the input section of the first multiplex inverter device and the first DC power supply, and between the input section of the second multiplex inverter device and the second DC power supply, respectively.
  • the plurality of solar cell groups forming the first photovoltaic power generation facility and the plurality of solar cell groups forming the second photovoltaic power generation facility may each be provided with a protection device that cuts off a short-circuit current.
  • AC capacitors may be provided between the output of the first multiple inverter device and the open delta connection transformer, and between the output of the second multiple inverter device and the open delta connection transformer. good.
  • the power conversion system may include a control device that cooperatively controls the first multiple inverter device and the second multiple inverter device.
  • the control device may cause the first multiple inverter device and the second multiple inverter device to output voltages having different signs.
  • the power conversion system according to the present disclosure may be applied to DC power supply equipment having a first DC power supply and a second DC power supply instead of the solar power generation equipment.
  • the input of the first multiple inverter device is connected to the first DC power supply
  • the input of the second multiple inverter device is connected to the second DC power supply.
  • the DC power supply equipment may be a distributed power supply, or more specifically, a storage battery equipment having a first storage battery and a second storage battery.
  • FIG. 1 is a circuit diagram showing the configuration of a power conversion system according to an embodiment of the present disclosure
  • FIG. 4 is a circuit diagram showing an example of the structure of a unit inverter
  • FIG. 4 is a diagram showing an example of coordinated control of the output voltage of the first multiple inverter device and the output voltage of the second multiple inverter device by the control device
  • FIG. 4 is a circuit diagram showing a configuration of a modification of the power conversion system of the embodiment of the present disclosure
  • FIG. 1 is a circuit diagram showing the configuration of the power conversion system according to the embodiment of the present disclosure.
  • the power conversion system 101 of the first embodiment is a system that converts DC power supplied from the photovoltaic power generation facility 50 into three-phase AC power.
  • the photovoltaic power generation facility 50 consists of two systems of a first photovoltaic power generation facility 51 and a second photovoltaic power generation facility 52 .
  • the first photovoltaic power generation facility 51 and the second photovoltaic power generation facility 52 are electrically insulated or connected via a resistor.
  • the first photovoltaic power generation facility 51 is configured by connecting a plurality of photovoltaic cell groups 51-1 to 51-n in parallel (where n is any natural number equal to or greater than 2).
  • the second photovoltaic power generation facility 52 is also configured by connecting a plurality of photovoltaic cell groups 52-1 to 52-m in parallel (where m is any natural number equal to or greater than 2).
  • Each solar cell group is configured by connecting a plurality of solar cells in series and in parallel.
  • a power conversion system 101 includes a single open delta connection transformer 30 connected to an AC power system, and a pair of multiple inverter devices 10 and 20 connected to the open delta connection transformer 30 .
  • a first multiple inverter device 10 and a second multiple inverter device 20 are connected to the open delta connection transformer 30 .
  • the first multiple inverter device 10 includes a pair of unit inverters 11a and 11b.
  • the number of unit inverters constituting the first multiple inverter device 10 may be plural, and therefore may be three or more.
  • the unit inverters 11a and 11b are voltage source inverters having switching elements composed of self arc-extinguishing power transistors such as MOSFETs and IGBTs, and are configured as three-phase inverters for converting DC power into three-phase AC power.
  • the unit inverters 11a and 11b have the same structure and are connected in parallel.
  • the first multiple inverter device 10 includes a pair of AC reactors 13a and 13b. Output terminals ua1, va1, wa1 of the unit inverter 11a and output terminals ub1, vb1, wb1 of the unit inverter 21b are connected to each other via AC reactors 13a, 13b for each common phase.
  • the AC reactor 13a on the unit inverter 11a side and the AC reactor 13b on the unit inverter 11b side may have the same capacity or may have different capacities.
  • An AC capacitor 17 is provided between the intermediate point between the AC reactors 13 a and 13 b connected in series and the transformer 30 .
  • the AC capacitor 17 forms a filter circuit together with the AC reactors 13a and 13b in order to suppress output current ripples of the unit inverters 11a and 11b due to switching of the switching elements.
  • the first multiple inverter device 10 includes a pair of DC capacitors 12a and 12b.
  • the DC capacitors 12a and 12b are connected in parallel between the input terminal of the unit inverter 11a and the input terminal of the unit inverter 11a.
  • the DC capacitor 12a on the side of the unit inverter 11a and the DC capacitor 12b on the side of the unit inverter 11b may have the same capacity or may have different capacities.
  • the first multiple inverter device 10 has an input section 10in to which DC power is input, and an output section 10out to output three-phase AC power.
  • the input 10in is connected to the midpoint between the parallel-connected DC capacitors 12a and 12b.
  • the output section 10out is connected to the AC capacitor 17 .
  • a current sensor 14 is provided between the AC capacitor 17 and the output section 10out.
  • the second multiple inverter device 20 has the same configuration as the first multiple inverter device 10.
  • the second multiple inverter device 20 includes a pair of unit inverters 21a and 21b.
  • the number of unit inverters constituting the second multiple inverter device 20 may be plural, and therefore may be three or more. Also, the number of unit inverters constituting the second multiple inverter device 20 may be different from the number of the first multiple inverter devices 10 .
  • FIG. 2 shows an example of the structure of the unit inverter.
  • FIG. 2 shows an example of the structure of the unit inverter 11a representing the unit inverters 11a, 11b, 21a, and 21b.
  • the unit inverter 11a may be configured as a three-phase, two-level inverter as shown in Example 1 of FIG.
  • the unit inverter 11a when the unit inverter 11a is a three-phase, three-level inverter, the DC capacitor 12a is composed of a positive electrode side capacitor 12aP and a negative electrode side capacitor 12aN.
  • the unit inverters 11a, 11b and the unit inverters 21a, 21b may have the same structure or may have different structures.
  • the unit inverters 11a and 11b may be 3-phase 3-level inverters
  • the unit inverters 21a and 21b may be 3-phase 2-level inverters.
  • the second multiple inverter device 20 has a pair of AC reactors 23a and 23b.
  • the output terminals ua2, va2, wa2 of the unit inverter 21a and the output terminals ub2, vb2, wb2 of the unit inverter 21b are connected to each other via AC reactors 23a, 23b for each common phase.
  • the AC reactor 23a on the unit inverter 21a side and the AC reactor 23b on the unit inverter 21b side may have the same capacity or may have different capacities.
  • An AC capacitor 27 is provided between the intermediate point between the AC reactors 23 a and 23 b connected in series and the transformer 30 .
  • the AC capacitor 27 forms a filter circuit together with the AC reactors 23a and 23b in order to suppress output current ripples of the unit inverters 21a and 21b due to switching of the switching elements.
  • the second multiple inverter device 20 includes a pair of DC capacitors 22a and 22b.
  • the DC capacitors 22a and 22b are connected in parallel between the input terminal of the unit inverter 21a and the input terminal of the unit inverter 21b.
  • the DC capacitor 22a on the side of the unit inverter 21a and the DC capacitor 22b on the side of the unit inverter 21b may have the same capacity or may have different capacities.
  • the second multiple inverter device 20 has an input section 20in to which DC power is input, and an output section 20out to output three-phase AC power.
  • the input section 20in is connected to the midpoint between the parallel-connected DC capacitors 22a and 22b.
  • the output section 20out is connected to the AC capacitor 27 .
  • a current sensor (not shown) is provided between the AC capacitor 17 and the output section 20out. However, since the current flowing through the current sensor of the first inverter 10 and the current flowing through the current sensor of the second inverter 20 have the same magnitude and opposite sign, one of the current sensors can be omitted.
  • An open-delta-connected transformer (hereinafter simply referred to as a transformer) 30 has primary-side windings 31u, 31v, and 31w that are open-delta-connected, and secondary-side windings 32u, 32v, and 32w that are star-connected. It is a three-phase transformer.
  • u, v, and w included in the reference numerals attached to each winding mean U-phase, V-phase, and W-phase, respectively.
  • the first multiple inverter device 10 and the second multiple inverter device 20 have respective outputs 10out and 20out connected to the primary windings 31u, 31v and 31w of the transformer 30, respectively.
  • the output section 10out of the first multiple inverter device 10 is connected to the winding start terminals of the primary windings 31u, 31v, and 31w
  • the output section 20out of the second multiple inverter device 20 is connected to the primary winding 31u. , 31v and 31w.
  • Secondary windings 32u, 32v, and 32w are connected to an AC power system.
  • a first photovoltaic power generation facility 51 is connected to the input section 10in of the first multiple inverter device 10 .
  • a DC switch 16 is provided between the input section 10in and the first photovoltaic power generation equipment 51 .
  • the input section 20in of the second multiplex inverter device 20 is connected to the second photovoltaic power generation facility 52 .
  • a DC switch 26 is provided between the input section 20in and the second photovoltaic power generation equipment 52 . The DC switches 16 and 26 are turned on when power generation by the photovoltaic power generation equipment 50 is started, and are opened when power generation is finished.
  • DC fuses 18-1 to 18-n are provided for each of the solar cell groups 51-1 to 51-n.
  • DC fuses 28-1 to 28-m are also provided between the DC switch 26 and the second solar power generation equipment 52 for each of the solar cell groups 52-1 to 52-m.
  • a DC fuse functions as a protective device for interrupting short-circuit currents. By providing a DC fuse for each solar cell group, a DC fuse with a small capacity can be used as each individual DC fuse.
  • circuit breakers and load switches can also be cited as examples of protective devices.
  • the power conversion system 101 includes a control device 40 .
  • the control device 40 transmits gate signals to the unit inverters 11 a and 11 b that constitute the first multiple inverter device 10 . More specifically, the control device 40 supplies a common gate signal GS1 to both unit inverters 11a and 11b to drive the respective switching elements.
  • both unit inverters 11a and 11b theoretically output voltage pulses with the same timing.
  • a slight timing shift occurs between the output voltage pulse of the unit inverter 11a and the output voltage pulse of the unit inverter 11b.
  • AC reactors 13a and 13b are provided between the output terminal of the unit inverter 11a and the output terminal of the unit inverter 11b. The AC reactors 13a and 13b suppress circulating currents between the unit inverters 11a and 11b caused by timing deviations of the output voltage pulses.
  • the control device 40 also transmits gate signals to the unit inverters 21 a and 21 b that make up the second multiplex inverter device 20 . More specifically, the control device 40 supplies a common gate signal GS2 to both unit inverters 21a and 21b to drive the respective switching elements. At this time, although a slight deviation may occur in the timing of the output voltage pulse between the unit inverters 21a and 21b, the circulating current generated between the unit inverters 21a and 21b due to the deviation is suppressed by the AC reactors 23a and 23b.
  • the control device 40 cooperatively controls the output voltage of the first multiple inverter device 10 and the output voltage of the second multiple inverter device 20 .
  • FIG. 3 is a diagram showing an example of the cooperative control.
  • the control device 40 generates a carrier wave based on a carrier frequency that determines the switching frequency, and has a phase difference of 180 degrees between the sine wave of the first voltage command value and the sine wave of the first voltage command value.
  • a sine wave of the second voltage command value is generated.
  • the gate signal GS1 to be supplied to the first multiple inverter device 10 is generated.
  • a gate signal GS2 to be supplied to the multiple inverter device 20 is generated.
  • the output current of the first multiple inverter device 10 and the output current of the second multiple inverter device 20 have different signs. Therefore, the output power of the first multiple inverter device 10 and the output power of the second multiple inverter device 20 have the same sign, and the two output powers are combined. As a result, the output capacity of the power conversion system 101 as a whole increases.
  • the gate signals GS1 and GS2 generated as described above a phase difference occurs in the switching timings of the in-phase switching elements of the first multiple inverter device 10 and the second multiple inverter device 20 .
  • the voltages applied to the primary windings 31u, 31v, and 31w of the transformer 30 are stepped with respect to the voltages output from the first multiple inverter device 10 and the second multiple inverter device 20, respectively.
  • the unit inverters 11a and 11b of the first multiple inverter device 10 are n1 level circuits and the unit inverters 21a and 21b of the second multiple inverter device 20 are n2 level circuits
  • the voltage is applied to the primary side of the transformer 30.
  • the voltage becomes (n1+n2-1) level.
  • output harmonic voltages and currents on the secondary side of transformer 30 are suppressed.
  • the output current of each phase of the first multiple inverter device 10 and the output current of each phase of the second multiple inverter device 20 have the same magnitude and opposite signs.
  • the current sensor 14 may be provided only in the first multiple inverter device 10 (or only in the second multiple inverter device 20). That is, the number of installed current sensors can be reduced.
  • the output current of the second multiplex inverter device 20 is also determined, so that the flow of circulating current on the AC side can be prevented. can be suppressed.
  • the input terminal of the unit inverter 21a and the input terminal of the unit inverter 21b are connected in parallel, and a common DC voltage is input from the second photovoltaic power generation equipment 52. Therefore, the circulating current generated between the unit inverters 21a and 21b is is suppressed. Furthermore, since the DC capacitors 22a and 22b are connected in parallel to the input terminals of the unit inverters 21a and 21b, the switching ripple caused by the switching of the switching elements is absorbed by the DC capacitors 22a and 22b.
  • the power conversion system 101 of this embodiment is a power conversion system having a DC fuse (protective device) that cuts off short-circuit current on the DC side.
  • a DC fuse protective device
  • the larger the capacity the greater the short-circuit current that flows through the DC fuse when the DC input is short-circuited, making it difficult to select a DC fuse with a sufficient short-circuit capacity.
  • the transformer 30 with an open winding on the primary side is used, and the primary winding of the transformer 30 is connected to the two systems of multiple inverter devices 10 and 20.
  • the DC sides of the multiple inverter devices 10 and 20 are independent of each other.
  • the voltage of the solar cell decreases at night. For this reason, if the multiple inverter devices 10 and 20 are left connected to the photovoltaic power generation facility 50, if the voltage of the solar cells falls below the minimum DC voltage of the multiple inverter devices 10 and 20 determined by the AC voltage, the solar cells will be removed from the system. power flows backwards.
  • One way to prevent this problem is to have a switch on the ac side and turn it on and off daily so that it disconnects from the grid side at night.
  • the required rated current increases, making it difficult to select an AC switch with a sufficient rated current.
  • the transformer 30 with an open winding on the primary side is used, and the primary winding of the transformer 30 is connected to the two systems of multiple inverter devices 10 and 20.
  • the DC sides of the multiple inverter devices 10 and 20 are independent of each other, and DC switches 16 and 26 are provided between the photovoltaic power generation facilities 51 and 52 to which they are connected, respectively.
  • the multiple inverter devices 10 and 20 are connected to the photovoltaic power generation facilities 51 and 52 divided into two, respectively, so that the DC switching devices installed on the DC sides of the multiple inverter devices 10 and 20 are connected.
  • the rated current of the devices 16 and 26 can be small.
  • the rated current of the DC switches 16 and 26 can be small. Further, according to the configuration of the power conversion system 101 of the present embodiment, since the short-circuit current on the DC side is small, it becomes easy to select the DC switches 16 and 26 that can cut off the short-circuit current on the DC side, and the DC fuse 18 -1 to 18-n and 28-1 to 28-m also have the effect of being easy to take protective cooperation.
  • the power conversion system is applied to the photovoltaic power generation facility, but the power conversion system according to the present disclosure includes a first DC power supply and a second DC power supply instead of the photovoltaic power generation facility. It may be applied to a DC power supply facility with The DC power supply facility may be a distributed power supply, or more specifically, a storage battery facility having a first storage battery and a second storage battery.
  • FIG. 4 is a circuit diagram showing a configuration of a modification of the power conversion system according to the embodiment of the present disclosure.
  • the power conversion system 102 of the modification is applied to the storage battery equipment 60 .
  • the storage battery equipment 60 comprises a first storage battery 61 and a second storage battery 62 electrically insulated from each other.
  • the first storage battery 61 is connected to the input section 10in of the first multiple inverter device 10 via a DC fuse 18 and a DC switch as protective equipment.
  • the second storage battery 62 is connected to the input section 20in of the second multiple inverter device 20 via a DC fuse 28 and a DC switch as protective equipment.
  • the single open delta connection transformer 30 is used to increase the output capacity. can be made possible.
  • First multiple inverter device 20 Second multiple inverter device 11a, 11b, 21a, 21b Unit inverter (three-phase inverter) 12a, 12b, 22a, 22b DC capacitors 13a, 13b, 23a, 23b AC reactor 14 Current sensors 16, 26 DC switches 17, 27 AC capacitors 18, 18-1 to 18-n, 28, 28-1 to 28- m DC fuse (protective device) 30 Open delta connection transformers 31u, 31v, 31w Primary windings 32u, 32v, 32w Secondary windings 40 Control device 50 Photovoltaic power generation equipment 51 First photovoltaic power generation equipment 52 Second photovoltaic power generation equipment 51-1 ⁇ 51-n, 52-1 to 52-m solar cell group 60 storage battery equipment 61 first storage battery 62 second storage battery 101, 102 power conversion system

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Abstract

The power conversion system of the present invention converts DC power supplied from a solar power generation facility into three-phase AC power, and comprises an open delta connection transformer that is connected to an AC power system, a first multiplexing inverter device, and a second multiplexing inverter device. The first multiplexing inverter device and second multiplexing inverter device each have a plurality of three-phase inverters connected in parallel, wherein output terminals of the plurality of three-phase inverters are connected to one another in each common phase via an AC reactor, and a DC capacitor is connected in parallel to input terminals of the plurality of three-phase inverters. The first multiplexing inverter device comprises an input unit that is connected to a first solar power generation facility, and an output unit that is connected to one end of a primary winding of each phase of the open delta connection transformer. The second multiplexing inverter device comprises an input unit that is connected to a second solar power generation facility, and an output unit that is connected to the other end of the primary winding of each phase of the open delta connection transformer.

Description

電力変換システムpower conversion system
　本開示は、電力変換システムに関し、詳しくは、太陽光発電システムに用いて好適な電力変換システムに関する。 The present disclosure relates to a power conversion system, and more particularly to a power conversion system suitable for use in a photovoltaic power generation system.
　近年の太陽光発電システムでは、太陽光発電設備を構成する太陽電池を複数枚直列及び並列に接続することによって、太陽光発電設備の大容量化が進められている。このため、太陽光発電設備の直流電力を交流電力に変換する電力変換システムにも、出力容量を増大させることが求められている。電力変換システムの出力容量を増大させる技術としては、例えば、特許文献１に開示された多重インバータ装置が知られている。 In recent photovoltaic power generation systems, the capacity of photovoltaic power generation equipment has been increased by connecting multiple solar cells that make up the photovoltaic power generation equipment in series and in parallel. For this reason, it is required to increase the output capacity of the power conversion system that converts the DC power of the photovoltaic power generation facility into the AC power. As a technique for increasing the output capacity of a power conversion system, for example, the multiple inverter device disclosed in Patent Document 1 is known.
　特許文献１には、第１及び第２の直流コンデンサからの直流電圧を３相交流電圧に変換する多重インバータ装置が開示されている。この多重インバータ装置は、第１及び第２の直流コンデンサに並列に接続される複数のユニットからなる。各ユニットは、２次巻線を交流回路に接続されたオープンデルタ結線変圧器と、第１及び第２のインバータ（３相インバータ）とから構成されている。第１のインバータは、入力端子を第１の直流コンデンサに接続され出力端子をオープンデルタ結線変圧器の１次巻線の一端に接続されている。第２のインバータは、入力端子を第２の直流コンデンサに接続され出力端子をオープンデルタ結線変圧器の１次巻線の他端に接続されている。各ユニットは、オープンデルタ結線変圧器を介して共通の交流回路に接続されている。 Patent Document 1 discloses a multiple inverter device that converts the DC voltage from the first and second DC capacitors into a three-phase AC voltage. This multiple inverter device consists of a plurality of units connected in parallel to the first and second DC capacitors. Each unit is composed of an open delta-connected transformer with a secondary winding connected to an AC circuit, and first and second inverters (three-phase inverters). The first inverter has an input terminal connected to the first DC capacitor and an output terminal connected to one end of the primary winding of the open delta transformer. The second inverter has an input terminal connected to the second DC capacitor and an output terminal connected to the other end of the primary winding of the open delta transformer. Each unit is connected to a common AC circuit through an open delta transformer.
日本特許第３２３７９８３号公報Japanese Patent No. 3237983
　特許文献１に開示された多重インバータ装置によれば、インバータの多重化によって出力容量を増大させることができる。しかし、インバータを多重化した分だけオープンデルタ結線変圧器も多数設ける必要が生じるため、特許文献１に記載の多重インバータ装置の利用は太陽光発電システムのコストアップを招いてしまう。 According to the multiple inverter device disclosed in Patent Document 1, the output capacity can be increased by multiplexing the inverters. However, since it is necessary to provide a large number of open delta connection transformers corresponding to the multiplexed inverters, the use of the multiplexed inverter device described in Patent Document 1 will increase the cost of the photovoltaic power generation system.
　本開示は、上述のような課題に鑑みてなされたものであり、太陽光発電設備から供給される直流電力を３相交流電力に変換する電力変換システムにおいて、単一のオープンデルタ結線変圧器を用いて出力容量の大容量化を可能にすることを目的とする。 The present disclosure has been made in view of the problems described above, and includes a power conversion system that converts DC power supplied from a photovoltaic power generation facility into three-phase AC power, and includes a single open delta connection transformer. The purpose is to make it possible to increase the output capacity by using
　本開示に係る電力変換システムは、太陽光発電設備から供給される直流電力を３相交流電力に変換するシステムであって、交流電力系統に接続された単一のオープンデルタ結線変圧器と第１多重インバータ装置と第２多重インバータ装置とを備える。第１多重インバータ装置と第２多重インバータ装置とは、ともに、並列に接続された複数の３相インバータを有し、複数の３相インバータの入力端子に直流コンデンサが並列に接続されて構成される。ここで、太陽光発電設備は、複数の太陽電池群が並列に接続されてなる第１太陽光発電設備と、複数の太陽電池群が並列に接続されてなる第２太陽光発電設備とを有する。第１多重インバータ装置は、第１太陽光発電設備に接続された入力部と、オープンデルタ結線変圧器の各相の１次巻線の一端に接続された出力部とを備える。第２多重インバータ装置は、第２太陽光発電設備に接続された入力部と、オープンデルタ結線変圧器の各相の１次巻線の他端に接続された出力部とを備える。 A power conversion system according to the present disclosure is a system that converts DC power supplied from a photovoltaic power generation facility into three-phase AC power, and includes a single open delta connection transformer connected to an AC power system and a first A multiple inverter device and a second multiple inverter device are provided. The first multiple inverter device and the second multiple inverter device both have a plurality of three-phase inverters connected in parallel, and are configured by connecting DC capacitors in parallel to the input terminals of the plurality of three-phase inverters. . Here, the photovoltaic power generation facility has a first photovoltaic power generation facility in which a plurality of solar cell groups are connected in parallel, and a second photovoltaic power generation facility in which a plurality of solar cell groups are connected in parallel. . A first multiple inverter arrangement has an input connected to the first photovoltaic power plant and an output connected to one end of the primary winding of each phase of the open delta connected transformer. A second multiple inverter arrangement has an input connected to the second photovoltaic power plant and an output connected to the other end of the primary winding of each phase of the open delta connected transformer.
　本開示に係る電力変換システムにおいて、第１多重インバータ装置と第２多重インバータ装置とは、ともに、複数の３相インバータの出力端子が共通相ごとに交流リアクトルを介して相互に接続されて構成されてもよい。また、第１多重インバータ装置の入力部と第１直流電源との間、及び第２多重インバータ装置の入力部と第２直流電源との間には、それぞれ、直流開閉器が設けられてもよい。また、第１太陽光発電設備を構成する複数の太陽電池群、及び第２太陽光発電設備を構成する複数の太陽電池群には、それぞれ、短絡電流を遮断する保護機器が設けられてもよい。また、第１多重インバータ装置の出力部とオープンデルタ結線変圧器との間、及び第２多重インバータ装置の出力部とオープンデルタ結線変圧器との間には、それぞれ、交流コンデンサが設けられてもよい。 In the power conversion system according to the present disclosure, both the first multiple inverter device and the second multiple inverter device are configured by connecting the output terminals of a plurality of three-phase inverters to each other via an AC reactor for each common phase. may A DC switch may be provided between the input section of the first multiplex inverter device and the first DC power supply, and between the input section of the second multiplex inverter device and the second DC power supply, respectively. . Further, the plurality of solar cell groups forming the first photovoltaic power generation facility and the plurality of solar cell groups forming the second photovoltaic power generation facility may each be provided with a protection device that cuts off a short-circuit current. . AC capacitors may be provided between the output of the first multiple inverter device and the open delta connection transformer, and between the output of the second multiple inverter device and the open delta connection transformer. good.
　また、本開示に係る電力変換システムは、第１多重インバータ装置と第２多重インバータ装置とを協調制御する制御装置を備えてもよい。制御装置は、第１多重インバータ装置と第２多重インバータ装置とに符号が異なる電圧を出力させてもよい。 Also, the power conversion system according to the present disclosure may include a control device that cooperatively controls the first multiple inverter device and the second multiple inverter device. The control device may cause the first multiple inverter device and the second multiple inverter device to output voltages having different signs.
　さらに、本開示に係る電力変換システムは、太陽光発電設備に代えて、第１直流電源と第２直流電源とを有する直流電源設備に適用してもよい。この場合、第１多重インバータ装置の入力部は第１直流電源に接続され、第２多重インバータ装置の入力部は第２直流電源に接続される。なお、直流電源設備は分散型電源でもよいし、より具体的には、第１蓄電池と第２蓄電池とを有する蓄電池設備でもよい。 Furthermore, the power conversion system according to the present disclosure may be applied to DC power supply equipment having a first DC power supply and a second DC power supply instead of the solar power generation equipment. In this case, the input of the first multiple inverter device is connected to the first DC power supply, and the input of the second multiple inverter device is connected to the second DC power supply. The DC power supply equipment may be a distributed power supply, or more specifically, a storage battery equipment having a first storage battery and a second storage battery.
　以上述べたように、本開示に係る電力変換システムによれば、単一のオープンデルタ結線変圧器を用いた３相インバータの多重化によって出力容量の大容量化を実現することができる。 As described above, according to the power conversion system according to the present disclosure, it is possible to increase the output capacity by multiplexing three-phase inverters using a single open-delta connection transformer.
本開示の実施形態の電力変換システムの構成を示す回路図である。1 is a circuit diagram showing the configuration of a power conversion system according to an embodiment of the present disclosure; FIG. 単位インバータの構造の例を示す回路図である。4 is a circuit diagram showing an example of the structure of a unit inverter; FIG. 制御装置による第１多重インバータ装置の出力電圧と第２多重インバータ装置の出力電圧との協調制御の例を示す図である。FIG. 4 is a diagram showing an example of coordinated control of the output voltage of the first multiple inverter device and the output voltage of the second multiple inverter device by the control device; 本開示の実施形態の電力変換システムの変形例の構成を示す回路図である。FIG. 4 is a circuit diagram showing a configuration of a modification of the power conversion system of the embodiment of the present disclosure;
　以下、本開示の実施形態について、図面を参照して説明する。以下に説明される実施形態において、各図において共通する要素には、同一の符号を付して重複する説明を省略又は簡略する。また、以下に示す実施の形態において各要素の個数、数量、量、範囲等の数に言及した場合、特に明示した場合や原理的に明らかにその数に特定される場合を除いて、その言及した数に、本開示に係る技術思想が限定されるものではない。また、以下に示す実施の形態において説明する構造は、特に明示した場合や明らかに原理的にそれに特定される場合を除いて、本開示に係る技術思想に必ずしも必須のものではない。 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the embodiments described below, the same reference numerals are given to elements that are common in each drawing, and overlapping descriptions are omitted or simplified. In addition, when referring to numbers such as the number, quantity, amount, range, etc. of each element in the embodiments shown below, unless otherwise specified or clearly specified in principle, the reference The technical idea according to the present disclosure is not limited to the number. In addition, the structures described in the embodiments shown below are not necessarily essential to the technical idea according to the present disclosure, unless otherwise specified or clearly specified in principle.
　図１は、本開示の実施形態の電力変換システムの構成を示す回路図である。第１実施形態の電力変換システム１０１は、太陽光発電設備５０から供給される直流電力を３相交流電力に変換するシステムである。太陽光発電設備５０は、第１太陽光発電設備５１と第２太陽光発電設備５２の２系統からなる。第１太陽光発電設備５１と第２太陽光発電設備５２とは電気的に絶縁されているか、或いは、抵抗を介して接続されている。第１太陽光発電設備５１は、複数の太陽電池群５１－１～５１－ｎが並列に接続されて構成されている（ただし、ｎは２以上の任意の自然数）。第２太陽光発電設備５２もまた、複数の太陽電池群５２－１～５２－ｍが並列に接続されて構成されている（ただし、ｍは２以上の任意の自然数）。各太陽電池群は、複数枚の太陽電池が直列及び並列に接続されて構成されている。 FIG. 1 is a circuit diagram showing the configuration of the power conversion system according to the embodiment of the present disclosure. The power conversion system 101 of the first embodiment is a system that converts DC power supplied from the photovoltaic power generation facility 50 into three-phase AC power. The photovoltaic power generation facility 50 consists of two systems of a first photovoltaic power generation facility 51 and a second photovoltaic power generation facility 52 . The first photovoltaic power generation facility 51 and the second photovoltaic power generation facility 52 are electrically insulated or connected via a resistor. The first photovoltaic power generation facility 51 is configured by connecting a plurality of photovoltaic cell groups 51-1 to 51-n in parallel (where n is any natural number equal to or greater than 2). The second photovoltaic power generation facility 52 is also configured by connecting a plurality of photovoltaic cell groups 52-1 to 52-m in parallel (where m is any natural number equal to or greater than 2). Each solar cell group is configured by connecting a plurality of solar cells in series and in parallel.
　電力変換システム１０１は、交流電力系統に接続された単一のオープンデルタ結線変圧器３０と、オープンデルタ結線変圧器３０に接続された一対の多重インバータ装置１０，２０とを備える。以下、２つの多重インバータ装置１０，２０を区別する場合には、第１多重インバータ装置１０、第２多重インバータ装置２０と称する。 A power conversion system 101 includes a single open delta connection transformer 30 connected to an AC power system, and a pair of multiple inverter devices 10 and 20 connected to the open delta connection transformer 30 . Hereinafter, when distinguishing between the two multiple inverter devices 10 and 20, they will be referred to as a first multiple inverter device 10 and a second multiple inverter device 20, respectively.
　第１多重インバータ装置１０は、一対の単位インバータ１１ａ，１１ｂを備える。ただし、第１多重インバータ装置１０を構成する単位インバータの数は複数であればよく、したがって、３以上でもよい。単位インバータ１１ａ，１１ｂは、ＭＯＳＦＥＴやＩＧＢＴなどの自己消弧形パワートランジスタからなるスイッチング素子を有する電圧形インバータであって、直流電力を３相交流電力に変換する３相インバータとして構成されている。単位インバータ１１ａと単位インバータ１１ｂとは同一の構造を有し、並列に接続されている。 The first multiple inverter device 10 includes a pair of unit inverters 11a and 11b. However, the number of unit inverters constituting the first multiple inverter device 10 may be plural, and therefore may be three or more. The unit inverters 11a and 11b are voltage source inverters having switching elements composed of self arc-extinguishing power transistors such as MOSFETs and IGBTs, and are configured as three-phase inverters for converting DC power into three-phase AC power. The unit inverters 11a and 11b have the same structure and are connected in parallel.
　第１多重インバータ装置１０は、一対の交流リアクトル１３ａ，１３ｂを備える。単位インバータ１１ａの出力端子ｕａ１，ｖａ１，ｗａ１と単位インバータ２１ｂの出力端子ｕｂ１，ｖｂ１，ｗｂ１とは、共通相ごとに交流リアクトル１３ａ，１３ｂを介して相互に接続されている。単位インバータ１１ａの側の交流リアクトル１３ａと単位インバータ１１ｂの側の交流リアクトル１３ｂとは同一の容量を有していてもよいし異なる容量を有していてもよい。 The first multiple inverter device 10 includes a pair of AC reactors 13a and 13b. Output terminals ua1, va1, wa1 of the unit inverter 11a and output terminals ub1, vb1, wb1 of the unit inverter 21b are connected to each other via AC reactors 13a, 13b for each common phase. The AC reactor 13a on the unit inverter 11a side and the AC reactor 13b on the unit inverter 11b side may have the same capacity or may have different capacities.
　直列に接続された交流リアクトル１３ａ，１３ｂの間の中間点と変圧器３０との間には、交流コンデンサ１７が設けられている。交流コンデンサ１７は、スイッチング素子のスイッチングに伴う単位インバータ１１ａ，１１ｂの出力電流リプルを抑制するため、交流リアクトル１３ａ，１３ｂとともにフィルタ回路を構成する。 An AC capacitor 17 is provided between the intermediate point between the AC reactors 13 a and 13 b connected in series and the transformer 30 . The AC capacitor 17 forms a filter circuit together with the AC reactors 13a and 13b in order to suppress output current ripples of the unit inverters 11a and 11b due to switching of the switching elements.
　第１多重インバータ装置１０は、一対の直流コンデンサ１２ａ，１２ｂを備える。直流コンデンサ１２ａ，１２ｂは、単位インバータ１１ａの入力端子と単位インバータ１１ａの入力端子との間に並列に接続されている。単位インバータ１１ａの側の直流コンデンサ１２ａと単位インバータ１１ｂの直流コンデンサ１２ｂとは同一の容量を有していてもよいし異なる容量を有していてもよい。 The first multiple inverter device 10 includes a pair of DC capacitors 12a and 12b. The DC capacitors 12a and 12b are connected in parallel between the input terminal of the unit inverter 11a and the input terminal of the unit inverter 11a. The DC capacitor 12a on the side of the unit inverter 11a and the DC capacitor 12b on the side of the unit inverter 11b may have the same capacity or may have different capacities.
　第１多重インバータ装置１０は、直流電力が入力される入力部１０ｉｎと、３相交流電力を出力する出力部１０ｏｕｔとを有する。入力部１０ｉｎは、並列に接続された直流コンデンサ１２ａ，１２ｂの間の中間点に接続されている。出力部１０ｏｕｔは、交流コンデンサ１７に接続されている。また、交流コンデンサ１７と出力部１０ｏｕｔとの間には電流センサ１４が設けられている。 The first multiple inverter device 10 has an input section 10in to which DC power is input, and an output section 10out to output three-phase AC power. The input 10in is connected to the midpoint between the parallel-connected DC capacitors 12a and 12b. The output section 10out is connected to the AC capacitor 17 . A current sensor 14 is provided between the AC capacitor 17 and the output section 10out.
　第２多重インバータ装置２０は、第１多重インバータ装置１０と同様の構成を有している。 The second multiple inverter device 20 has the same configuration as the first multiple inverter device 10.
　第２多重インバータ装置２０は、一対の単位インバータ２１ａ，２１ｂを備える。ただし、第１多重インバータ装置１０と同様に、第２多重インバータ装置２０を構成する単位インバータの数は複数であればよく、したがって、３以上でもよい。また、第２多重インバータ装置２０を構成する単位インバータの数は第１多重インバータ装置１０の数と異なっていてもよい。ここで、単位インバータの構造の例を図２に示す。図２では、単位インバータ１１ａ，１１ｂ，２１ａ，２１ｂを代表して単位インバータ１１ａの構造の例が示されている。単位インバータ１１ａは、図２の例１に示すように、３相２レベルインバータとして構成されてもよいし、例２に示すように、３相３レベルインバータとして構成されてもよい。ただし、単位インバータ１１ａが３相３レベルインバータの場合、直流コンデンサ１２ａは正極側のコンデンサ１２ａＰと負極側のコンデンサ１２ａＮとから構成される。また、単位インバータ１１ａ，１１ｂと単位インバータ２１ａ，２１ｂとは構造が同一でもよいし、異なっていてもよい。例えば、単位インバータ１１ａ，１１ｂが３相３レベルインバータで、単位インバータ２１ａ，２１ｂが３相２レベルインバータであってもよい。 The second multiple inverter device 20 includes a pair of unit inverters 21a and 21b. However, as with the first multiple inverter device 10, the number of unit inverters constituting the second multiple inverter device 20 may be plural, and therefore may be three or more. Also, the number of unit inverters constituting the second multiple inverter device 20 may be different from the number of the first multiple inverter devices 10 . Here, FIG. 2 shows an example of the structure of the unit inverter. FIG. 2 shows an example of the structure of the unit inverter 11a representing the unit inverters 11a, 11b, 21a, and 21b. The unit inverter 11a may be configured as a three-phase, two-level inverter as shown in Example 1 of FIG. 2, or may be configured as a three-phase, three-level inverter as shown in Example 2. FIG. However, when the unit inverter 11a is a three-phase, three-level inverter, the DC capacitor 12a is composed of a positive electrode side capacitor 12aP and a negative electrode side capacitor 12aN. Further, the unit inverters 11a, 11b and the unit inverters 21a, 21b may have the same structure or may have different structures. For example, the unit inverters 11a and 11b may be 3-phase 3-level inverters, and the unit inverters 21a and 21b may be 3-phase 2-level inverters.
　第２多重インバータ装置２０は、一対の交流リアクトル２３ａ，２３ｂを備える。単位インバータ２１ａの出力端子ｕａ２，ｖａ２，ｗａ２と単位インバータ２１ｂの出力端子ｕｂ２，ｖｂ２，ｗｂ２とは、共通相ごとに交流リアクトル２３ａ，２３ｂを介して相互に接続されている。単位インバータ２１ａの側の交流リアクトル２３ａと単位インバータ２１ｂの側の交流リアクトル２３ｂとは同一の容量を有していてもよいし異なる容量を有していてもよい。 The second multiple inverter device 20 has a pair of AC reactors 23a and 23b. The output terminals ua2, va2, wa2 of the unit inverter 21a and the output terminals ub2, vb2, wb2 of the unit inverter 21b are connected to each other via AC reactors 23a, 23b for each common phase. The AC reactor 23a on the unit inverter 21a side and the AC reactor 23b on the unit inverter 21b side may have the same capacity or may have different capacities.
　直列に接続された交流リアクトル２３ａ，２３ｂの間の中間点と変圧器３０との間には、交流コンデンサ２７が設けられている。交流コンデンサ２７は、スイッチング素子のスイッチングに伴う単位インバータ２１ａ，２１ｂの出力電流リプルを抑制するため、交流リアクトル２３ａ，２３ｂとともにフィルタ回路を構成する。 An AC capacitor 27 is provided between the intermediate point between the AC reactors 23 a and 23 b connected in series and the transformer 30 . The AC capacitor 27 forms a filter circuit together with the AC reactors 23a and 23b in order to suppress output current ripples of the unit inverters 21a and 21b due to switching of the switching elements.
　第２多重インバータ装置２０は、一対の直流コンデンサ２２ａ，２２ｂを備える。直流コンデンサ２２ａ，２２ｂは、単位インバータ２１ａの入力端子と単位インバータ２１ｂの入力端子との間に並列に接続されている。単位インバータ２１ａの側の直流コンデンサ２２ａと単位インバータ２１ｂの直流コンデンサ２２ｂとは同一の容量を有していてもよいし異なる容量を有していてもよい。 The second multiple inverter device 20 includes a pair of DC capacitors 22a and 22b. The DC capacitors 22a and 22b are connected in parallel between the input terminal of the unit inverter 21a and the input terminal of the unit inverter 21b. The DC capacitor 22a on the side of the unit inverter 21a and the DC capacitor 22b on the side of the unit inverter 21b may have the same capacity or may have different capacities.
　第２多重インバータ装置２０は、直流電力が入力される入力部２０ｉｎと、３相交流電力を出力する出力部２０ｏｕｔとを有する。入力部２０ｉｎは、並列に接続された直流コンデンサ２２ａ，２２ｂの間の中間点に接続されている。出力部２０ｏｕｔは、交流コンデンサ２７に接続されている。また、交流コンデンサ１７と出力部２０ｏｕｔとの間には図示しない電流センサが設けられている。ただし、第１インバータ１０の電流センサに流れる電流と、第２インバータ２０の電流センサに流れる電流とは大きさが等しく逆符号となるので、何れか一方の電流センサは省略することができる。 The second multiple inverter device 20 has an input section 20in to which DC power is input, and an output section 20out to output three-phase AC power. The input section 20in is connected to the midpoint between the parallel-connected DC capacitors 22a and 22b. The output section 20out is connected to the AC capacitor 27 . A current sensor (not shown) is provided between the AC capacitor 17 and the output section 20out. However, since the current flowing through the current sensor of the first inverter 10 and the current flowing through the current sensor of the second inverter 20 have the same magnitude and opposite sign, one of the current sensors can be omitted.
　オープンデルタ結線変圧器（以下、単に変圧器という）３０は、１次側の巻線３１ｕ，３１ｖ，３１ｗをオープンデルタ結線とされ、２次側の巻線３２ｕ，３２ｖ，３２ｗをスター結線とされた３相変圧器である。ここで、各巻線に付された符号に含まれるｕ、ｖ、ｗは、それぞれＵ相、Ｖ相、Ｗ相を意味している。第１多重インバータ装置１０及び第２多重インバータ装置２０は、それぞれの出力部１０ｏｕｔ，２０ｏｕｔを変圧器３０の１次巻線３１ｕ，３１ｖ，３１ｗに接続されている。詳しくは、第１多重インバータ装置１０の出力部１０ｏｕｔは、１次巻線３１ｕ，３１ｖ，３１ｗの巻始側端子に接続され、第２多重インバータ装置２０の出力部２０ｏｕｔは、１次巻線３１ｕ，３１ｖ，３１ｗの巻終側端子に接続されている。２次側の巻線３２ｕ，３２ｖ，３２ｗは、交流電力系統に接続されている。 An open-delta-connected transformer (hereinafter simply referred to as a transformer) 30 has primary- side windings 31u, 31v, and 31w that are open-delta-connected, and secondary- side windings 32u, 32v, and 32w that are star-connected. It is a three-phase transformer. Here, u, v, and w included in the reference numerals attached to each winding mean U-phase, V-phase, and W-phase, respectively. The first multiple inverter device 10 and the second multiple inverter device 20 have respective outputs 10out and 20out connected to the primary windings 31u, 31v and 31w of the transformer 30, respectively. Specifically, the output section 10out of the first multiple inverter device 10 is connected to the winding start terminals of the primary windings 31u, 31v, and 31w, and the output section 20out of the second multiple inverter device 20 is connected to the primary winding 31u. , 31v and 31w. Secondary windings 32u, 32v, and 32w are connected to an AC power system.
　第１多重インバータ装置１０の入力部１０ｉｎには、第１太陽光発電設備５１が接続されている。入力部１０ｉｎと第１太陽光発電設備５１との間には、直流開閉器１６が設けられている。一方、第２多重インバータ装置２０の入力部２０ｉｎには、第２太陽光発電設備５２が接続されている。入力部２０ｉｎと第２太陽光発電設備５２との間には、直流開閉器２６が設けられている。直流開閉器１６，２６は、太陽光発電設備５０による発電開始時に投入され、発電終了時に開放される。 A first photovoltaic power generation facility 51 is connected to the input section 10in of the first multiple inverter device 10 . A DC switch 16 is provided between the input section 10in and the first photovoltaic power generation equipment 51 . On the other hand, the input section 20in of the second multiplex inverter device 20 is connected to the second photovoltaic power generation facility 52 . A DC switch 26 is provided between the input section 20in and the second photovoltaic power generation equipment 52 . The DC switches 16 and 26 are turned on when power generation by the photovoltaic power generation equipment 50 is started, and are opened when power generation is finished.
　直流開閉器１６と第１太陽光発電設備５１との間には、直流ヒューズ１８－１～１８－ｎが太陽電池群５１－１～５１－ｎごとに設けられている。直流開閉器２６と第２太陽光発電設備５２との間にも、直流ヒューズ２８－１～２８－ｍが太陽電池群５２－１～５２－ｍごとに設けられている。直流ヒューズは、短絡電流を遮断するための保護機器として機能する。太陽電池群ごとに直流ヒューズを設けることで、個々の直流ヒューズとしては容量の小さいものを用いることができる。なお、保護機器の例としては、直流ヒューズの他にも遮断器や負荷開閉器などを挙げることができる。 Between the DC switch 16 and the first photovoltaic power generation equipment 51, DC fuses 18-1 to 18-n are provided for each of the solar cell groups 51-1 to 51-n. DC fuses 28-1 to 28-m are also provided between the DC switch 26 and the second solar power generation equipment 52 for each of the solar cell groups 52-1 to 52-m. A DC fuse functions as a protective device for interrupting short-circuit currents. By providing a DC fuse for each solar cell group, a DC fuse with a small capacity can be used as each individual DC fuse. In addition to DC fuses, circuit breakers and load switches can also be cited as examples of protective devices.
　電力変換システム１０１は制御装置４０を備える。制御装置４０は、第１多重インバータ装置１０を構成する単位インバータ１１ａ，１１ｂにゲート信号を送信する。より具体的には、制御装置４０は、共通のゲート信号ＧＳ１を両方の単位インバータ１１ａ，１１ｂに供給し、それぞれのスイッチング素子を駆動する。 The power conversion system 101 includes a control device 40 . The control device 40 transmits gate signals to the unit inverters 11 a and 11 b that constitute the first multiple inverter device 10 . More specifically, the control device 40 supplies a common gate signal GS1 to both unit inverters 11a and 11b to drive the respective switching elements.
　共通のゲート信号が供給されることで、理論的には両方の単位インバータ１１ａ，１１ｂからはタイミングの揃った電圧パルスが出力される。しかし、現実的には、スイッチング素子の特性ばらつきや配線遅延により、単位インバータ１１ａの出力電圧パルスと単位インバータ１１ｂの出力電圧パルスとの間には僅かにタイミングのずれが生じる。この点に関し、電力変換システム１０１では、単位インバータ１１ａの出力端子と単位インバータ１１ｂの出力端子との間に交流リアクトル１３ａ，１３ｂが設けられている。交流リアクトル１３ａ，１３ｂは、出力電圧パルスのタイミングのずれにより生じる単位インバータ１１ａ，１１ｂ間の循環電流を抑制する。 By supplying a common gate signal, both unit inverters 11a and 11b theoretically output voltage pulses with the same timing. However, in reality, due to variations in characteristics of switching elements and wiring delays, a slight timing shift occurs between the output voltage pulse of the unit inverter 11a and the output voltage pulse of the unit inverter 11b. Regarding this point, in the power conversion system 101, AC reactors 13a and 13b are provided between the output terminal of the unit inverter 11a and the output terminal of the unit inverter 11b. The AC reactors 13a and 13b suppress circulating currents between the unit inverters 11a and 11b caused by timing deviations of the output voltage pulses.
　制御装置４０は、第２多重インバータ装置２０を構成する単位インバータ２１ａ，２１ｂにもゲート信号を送信する。より具体的には、制御装置４０は、共通のゲート信号ＧＳ２を両方の単位インバータ２１ａ，２１ｂに供給し、それぞれのスイッチング素子を駆動する。このとき、単位インバータ２１ａ，２１ｂ間で出力電圧パルスのタイミングに僅かにずれが生じうるが、そのずれによって単位インバータ２１ａ，２１ｂ間に生じる循環電流は、交流リアクトル２３ａ，２３ｂによって抑制される。 The control device 40 also transmits gate signals to the unit inverters 21 a and 21 b that make up the second multiplex inverter device 20 . More specifically, the control device 40 supplies a common gate signal GS2 to both unit inverters 21a and 21b to drive the respective switching elements. At this time, although a slight deviation may occur in the timing of the output voltage pulse between the unit inverters 21a and 21b, the circulating current generated between the unit inverters 21a and 21b due to the deviation is suppressed by the AC reactors 23a and 23b.
　制御装置４０は、第１多重インバータ装置１０の出力電圧と第２多重インバータ装置２０の出力電圧とを協調制御する。図３は、その協調制御の例を示す図である。制御装置４０は、スイッチング周波数を決定するキャリア周波数に基づいてキャリア波を生成するとともに、第１電圧指令値の正弦波と、第１電圧指令値の正弦波に対して１８０度の位相差を有する第２電圧指令値の正弦波とを生成する。そして、キャリア波と第１電圧指令値の正弦波とに基づいて第１多重インバータ装置１０に供給するゲート信号ＧＳ１を生成し、キャリア波と第１電圧指令値の正弦波とに基づいて第２多重インバータ装置２０に供給するゲート信号ＧＳ２を生成する。 The control device 40 cooperatively controls the output voltage of the first multiple inverter device 10 and the output voltage of the second multiple inverter device 20 . FIG. 3 is a diagram showing an example of the cooperative control. The control device 40 generates a carrier wave based on a carrier frequency that determines the switching frequency, and has a phase difference of 180 degrees between the sine wave of the first voltage command value and the sine wave of the first voltage command value. A sine wave of the second voltage command value is generated. Based on the carrier wave and the sine wave of the first voltage command value, the gate signal GS1 to be supplied to the first multiple inverter device 10 is generated. A gate signal GS2 to be supplied to the multiple inverter device 20 is generated.
　このように生成されたゲート信号ＧＳ１，ＧＳ２が供給されることで、第１多重インバータ装置１０と第２多重インバータ装置２０とからは、互いに符号が異なる電圧が出力される。変圧器３０の１次巻線３１ｕ，３１ｖ，３１ｗには、第１多重インバータ装置１０の出力電圧と第２多重インバータ装置２０の出力電圧との差電圧が印可される。このため、符号が異なる電圧が第１多重インバータ装置１０と第２多重インバータ装置２０とから出力される。一方で、第１多重インバータ装置１０の出力の各相と、第２多重インバータ装置２０の出力の対応する各相は、それぞれ変圧器３０の同じ１次巻線に接続されている。したがって、第１多重インバータ装置１０の出力電流と、第２多重インバータ装置２０の出力電流とは互いに符号が異なる。したがって、第１多重インバータ装置１０の出力電力と、第２多重インバータ装置２０の出力電力とは互いに同符号となり、両者の出力電力は合成される。その結果、電力変換システム１０１全体としての出力容量は増大する。 By supplying the gate signals GS1 and GS2 generated in this manner, voltages having different signs are output from the first multiple inverter device 10 and the second multiple inverter device 20 . A differential voltage between the output voltage of the first multiple inverter device 10 and the output voltage of the second multiple inverter device 20 is applied to the primary windings 31u, 31v, and 31w of the transformer 30 . Therefore, voltages with different signs are output from the first multiple inverter device 10 and the second multiple inverter device 20 . On the other hand, each phase of the output of the first multiple inverter device 10 and each corresponding phase of the output of the second multiple inverter device 20 are connected to the same primary winding of the transformer 30 respectively. Therefore, the output current of the first multiple inverter device 10 and the output current of the second multiple inverter device 20 have different signs. Therefore, the output power of the first multiple inverter device 10 and the output power of the second multiple inverter device 20 have the same sign, and the two output powers are combined. As a result, the output capacity of the power conversion system 101 as a whole increases.
　また、上記のように生成されたゲート信号ＧＳ１，ＧＳ２が供給されることで、第１多重インバータ装置１０と第２多重インバータ装置２０の同相のスイッチング素子において互いにスイッチングのタイミングに位相差が生じる。これにより、変圧器３０の１次巻線３１ｕ，３１ｖ，３１ｗに印可される電圧は、第１多重インバータ装置１０及び第２多重インバータ装置２０のそれぞれから出力される電圧に対して多段化される。例えば、第１多重インバータ装置１０の単位インバータ１１ａ，１１ｂがｎ１レベル回路で、第２多重インバータ装置２０の単位インバータ２１ａ，２１ｂがｎ２レベル回路の場合、変圧器３０の１次側に印可される電圧は（ｎ１＋ｎ２－１）レベルとなる。その結果、変圧器３０の２次側の出力高調波電圧及び電流は抑制される。 Also, by supplying the gate signals GS1 and GS2 generated as described above, a phase difference occurs in the switching timings of the in-phase switching elements of the first multiple inverter device 10 and the second multiple inverter device 20 . As a result, the voltages applied to the primary windings 31u, 31v, and 31w of the transformer 30 are stepped with respect to the voltages output from the first multiple inverter device 10 and the second multiple inverter device 20, respectively. . For example, when the unit inverters 11a and 11b of the first multiple inverter device 10 are n1 level circuits and the unit inverters 21a and 21b of the second multiple inverter device 20 are n2 level circuits, the voltage is applied to the primary side of the transformer 30. The voltage becomes (n1+n2-1) level. As a result, output harmonic voltages and currents on the secondary side of transformer 30 are suppressed.
　なお、第１多重インバータ装置１０の各相の出力電流と第２多重インバータ装置２０の各相の出力電流とは、互いに大きさが等しく逆符号となる。この場合、図１に示すように、電流センサ１４は、第１多重インバータ装置１０のみ（或いは第２多重インバータ装置２０のみ）に設ければよい。つまり、設置する電流センサの個数を減らすことができる。また、第１多重インバータ装置１０に設けた電流センサ１４の値に基づいて三相電流を制御することで、第２多重インバータ装置２０の出力電流も定まるため、交流側に循環電流が流れることを抑制することができる。 The output current of each phase of the first multiple inverter device 10 and the output current of each phase of the second multiple inverter device 20 have the same magnitude and opposite signs. In this case, as shown in FIG. 1, the current sensor 14 may be provided only in the first multiple inverter device 10 (or only in the second multiple inverter device 20). That is, the number of installed current sensors can be reduced. In addition, by controlling the three-phase current based on the value of the current sensor 14 provided in the first multiplex inverter device 10, the output current of the second multiplex inverter device 20 is also determined, so that the flow of circulating current on the AC side can be prevented. can be suppressed.
　また、単位インバータ１１ａ，１１ｂ間で入力される直流電圧に差があると、共通のゲート信号でスイッチング素子駆動した場合に出力電圧の大きさに差が生じ、循環電流を生じさせる。この点に関し、電力変換システム１０１では、単位インバータ１１ａの入力端子と単位インバータ１１ｂの入力端子とは並列接続され、第１太陽光発電設備５１より共通の直流電圧が入力される。これにより、入力される直流電圧の大きさに差は生じず、単位インバータ１１ａ，１１ｂ間に生じる循環電流は抑制される。また、単位インバータ１１ａ，１１ｂの入力端子には、直流コンデンサ１２ａ，１２ｂが並列に接続されているので、スイッチング素子のスイッチングに伴うスイッチングリプルは直流コンデンサ１２ａ，１２ｂによって吸収される。 Also, if there is a difference in the DC voltages input between the unit inverters 11a and 11b, when the switching elements are driven by a common gate signal, there will be a difference in the magnitude of the output voltage and a circulating current will be generated. Regarding this point, in the power conversion system 101 , the input terminal of the unit inverter 11 a and the input terminal of the unit inverter 11 b are connected in parallel, and a common DC voltage is input from the first photovoltaic power generation equipment 51 . As a result, no difference occurs in the magnitude of the input DC voltage, and the circulating current generated between the unit inverters 11a and 11b is suppressed. In addition, since DC capacitors 12a and 12b are connected in parallel to the input terminals of the unit inverters 11a and 11b, the switching ripple caused by the switching of the switching elements is absorbed by the DC capacitors 12a and 12b.
　同様に、単位インバータ２１ａの入力端子と単位インバータ２１ｂの入力端子とは並列接続され、第２太陽光発電設備５２より共通の直流電圧が入力されるので、単位インバータ２１ａ，２１ｂ間に生じる循環電流は抑制される。さらに、単位インバータ２１ａ，２１ｂの入力端子には、直流コンデンサ２２ａ，２２ｂが並列に接続されているので、スイッチング素子のスイッチングに伴うスイッチングリプルは直流コンデンサ２２ａ，２２ｂによって吸収される。 Similarly, the input terminal of the unit inverter 21a and the input terminal of the unit inverter 21b are connected in parallel, and a common DC voltage is input from the second photovoltaic power generation equipment 52. Therefore, the circulating current generated between the unit inverters 21a and 21b is is suppressed. Furthermore, since the DC capacitors 22a and 22b are connected in parallel to the input terminals of the unit inverters 21a and 21b, the switching ripple caused by the switching of the switching elements is absorbed by the DC capacitors 22a and 22b.
　以上が本実施形態の電力変換システム１０１についての説明である。本実施形態の電力変換システム１０１によれば、上述の効果の他にもさらに以下のような効果を得ることができる。 The above is the description of the power conversion system 101 of the present embodiment. According to the power conversion system 101 of this embodiment, the following effects can be obtained in addition to the effects described above.
　本実施形態の電力変換システム１０１は、直流側に短絡電流を遮断する直流ヒューズ（保護機器）を有する電力変換システムである。このような電力変換システムでは、大容量化すればするほど、直流入力の短絡時に直流ヒューズに流れる短絡電流が大きくなり、十分な短絡容量の直流ヒューズを選定することは困難となる。仮に、太陽電池群が接続される直流入力の１つで短絡が発生すると、直流側を並列接続された単位インバータに接続されるすべての直流コンデンサからの短絡電流と、短絡が発生した直流入力を除くすべての直流入力に接続された太陽電池からの短絡電流との合計の短絡電流が短絡点に流れこむ。ゆえに、電力変換システムを大容量化するほど、合計の直流コンデンサ容量と太陽電池の並列数が増大するため、短絡電流は大きくなる。 The power conversion system 101 of this embodiment is a power conversion system having a DC fuse (protective device) that cuts off short-circuit current on the DC side. In such a power conversion system, the larger the capacity, the greater the short-circuit current that flows through the DC fuse when the DC input is short-circuited, making it difficult to select a DC fuse with a sufficient short-circuit capacity. If a short-circuit occurs in one of the DC inputs to which the solar cell group is connected, the short-circuit current from all the DC capacitors connected to the unit inverters connected in parallel on the DC side and the short-circuited DC input The total short circuit current from the solar cells connected to all DC inputs except the short circuit current flows into the short circuit point. Therefore, as the capacity of the power conversion system increases, the total DC capacitor capacity and the number of solar cells connected in parallel increase, so the short-circuit current increases.
　上記問題に関し、本実施形態の電力変換システム１０１では、１次側がオープン巻線の変圧器３０が用いられ、変圧器３０の１次巻線に２系統の多重インバータ装置１０，２０が接続されている。そして、多重インバータ装置１０，２０の互いの直流側は独立している。このような構成により、直流ヒューズ（保護機器）１８－1～１８－ｎ，２８－1～２８－ｍの遮断容量を大きくしなくても、単一の変圧器３０に接続される電力変換システム１０１を大容量化することができる。 Regarding the above problem, in the power conversion system 101 of this embodiment, the transformer 30 with an open winding on the primary side is used, and the primary winding of the transformer 30 is connected to the two systems of multiple inverter devices 10 and 20. there is The DC sides of the multiple inverter devices 10 and 20 are independent of each other. With such a configuration, a power conversion system connected to a single transformer 30 without increasing the breaking capacities of the DC fuses (protective devices) 18-1 to 18-n and 28-1 to 28-m. 101 can be increased in capacity.
　また、夜間には太陽電池の電圧が減少する。このため、太陽光発電設備５０に多重インバータ装置１０，２０を接続したままにすると、交流電圧によって決まる多重インバータ装置１０，２０の最低直流電圧を太陽電池の電圧が下回った場合、系統から太陽電池に電力が逆流してしまう。この問題を防ぐ一つの方法は、交流側に開閉器を設け、夜間に系統側から切断するよう、開閉器を毎日入り切りすることである。しかし、電力変換システムが大容量化すればするほど、必要な定格電流が大きくなり、十分な定格電流の交流開閉器を選定することは困難となる。 Also, the voltage of the solar cell decreases at night. For this reason, if the multiple inverter devices 10 and 20 are left connected to the photovoltaic power generation facility 50, if the voltage of the solar cells falls below the minimum DC voltage of the multiple inverter devices 10 and 20 determined by the AC voltage, the solar cells will be removed from the system. power flows backwards. One way to prevent this problem is to have a switch on the ac side and turn it on and off daily so that it disconnects from the grid side at night. However, as the capacity of the power conversion system increases, the required rated current increases, making it difficult to select an AC switch with a sufficient rated current.
　上記問題に関し、本実施形態の電力変換システム１０１では、１次側がオープン巻線の変圧器３０が用いられ、変圧器３０の１次巻線に２系統の多重インバータ装置１０，２０が接続されている。そして、多重インバータ装置１０，２０の互いの直流側は独立し、それぞれが接続される太陽光発電設備５１，５２との間に直流開閉器１６，２６が設けられている。このような構成によれば、２分割された太陽光発電設備５１，５２のそれぞれに多重インバータ装置１０，２０が接続されることで、多重インバータ装置１０，２０の直流側に設置される直流開閉器１６，２６の定格電流は小さくて済む。交流側に開閉器を設ける場合に比較しても、直流開閉器１６，２６の定格電流は小さくて済む。また、本実施形態の電力変換システム１０１の構成によれば、直流側の短絡電流が小さくなるため、直流側の短絡電流を遮断できる直流開閉器１６，２６の選定が容易になり、直流ヒューズ１８－1～１８－ｎ，２８－1～２８－ｍとの保護協調を取りやすいという効果もある。 Regarding the above problem, in the power conversion system 101 of this embodiment, the transformer 30 with an open winding on the primary side is used, and the primary winding of the transformer 30 is connected to the two systems of multiple inverter devices 10 and 20. there is The DC sides of the multiple inverter devices 10 and 20 are independent of each other, and DC switches 16 and 26 are provided between the photovoltaic power generation facilities 51 and 52 to which they are connected, respectively. According to such a configuration, the multiple inverter devices 10 and 20 are connected to the photovoltaic power generation facilities 51 and 52 divided into two, respectively, so that the DC switching devices installed on the DC sides of the multiple inverter devices 10 and 20 are connected. The rated current of the devices 16 and 26 can be small. Compared to the case where the switches are provided on the AC side, the rated current of the DC switches 16 and 26 can be small. Further, according to the configuration of the power conversion system 101 of the present embodiment, since the short-circuit current on the DC side is small, it becomes easy to select the DC switches 16 and 26 that can cut off the short-circuit current on the DC side, and the DC fuse 18 -1 to 18-n and 28-1 to 28-m also have the effect of being easy to take protective cooperation.
　なお、本実施形態では、電力変換システムは太陽光発電設備に適用されているが、本開示に係る電力変換システムは、太陽光発電設備に代えて、第１直流電源と第２直流電源とを有する直流電源設備に適用してもよい。直流電源設備は分散型電源でもよいし、より具体的には、第１蓄電池と第２蓄電池とを有する蓄電池設備でもよい。 Note that in the present embodiment, the power conversion system is applied to the photovoltaic power generation facility, but the power conversion system according to the present disclosure includes a first DC power supply and a second DC power supply instead of the photovoltaic power generation facility. It may be applied to a DC power supply facility with The DC power supply facility may be a distributed power supply, or more specifically, a storage battery facility having a first storage battery and a second storage battery.
　図４は、本開示の実施形態の電力変換システムの変形例の構成を示す回路図である。変形例の電力変換システム１０２は、蓄電池設備６０に適用されている。蓄電池設備６０は、互いに電気的に絶縁された第１蓄電池６１と第２蓄電池６２とからなる。第１蓄電池６１は、保護機器としての直流ヒューズ１８と直流開閉器とを介して第１多重インバータ装置１０の入力部１０ｉｎに接続されている。第２蓄電池６２は、保護機器としての直流ヒューズ２８と直流開閉器とを介して第２多重インバータ装置２０の入力部２０ｉｎに接続されている。この変形例のように、蓄電池設備６０から供給される直流電力を３相交流電力に変換する電力変換システム１０２においても、単一のオープンデルタ結線変圧器３０を用いて出力容量の大容量化を可能にすることができる。 FIG. 4 is a circuit diagram showing a configuration of a modification of the power conversion system according to the embodiment of the present disclosure. The power conversion system 102 of the modification is applied to the storage battery equipment 60 . The storage battery equipment 60 comprises a first storage battery 61 and a second storage battery 62 electrically insulated from each other. The first storage battery 61 is connected to the input section 10in of the first multiple inverter device 10 via a DC fuse 18 and a DC switch as protective equipment. The second storage battery 62 is connected to the input section 20in of the second multiple inverter device 20 via a DC fuse 28 and a DC switch as protective equipment. As in this modification, even in the power conversion system 102 that converts the DC power supplied from the storage battery equipment 60 into the three-phase AC power, the single open delta connection transformer 30 is used to increase the output capacity. can be made possible.
１０　第１多重インバータ装置
２０　第２多重インバータ装置
１１ａ，１１ｂ，２１ａ，２１ｂ　単位インバータ（３相インバータ）
１２ａ，１２ｂ，２２ａ，２２ｂ　直流コンデンサ
１３ａ，１３ｂ，２３ａ，２３ｂ　交流リアクトル
１４　電流センサ
１６，２６　直流開閉器
１７，２７　交流コンデンサ
１８，１８－1～１８－ｎ，２８，２８－1～２８－ｍ　直流ヒューズ（保護機器）
３０　オープンデルタ結線変圧器
３１ｕ，３１ｖ，３１ｗ　１次巻線
３２ｕ，３２ｖ，３２ｗ　２次巻線
４０　制御装置
５０　太陽光発電設備
５１　第１太陽光発電設備
５２　第２太陽光発電設備
５１－1～５１－ｎ，５２－1～５２－ｍ　太陽電池群
６０　蓄電池設備
６１　第１蓄電池
６２　第２蓄電池
１０１，１０２　電力変換システム 10 First multiple inverter device 20 Second multiple inverter device 11a, 11b, 21a, 21b Unit inverter (three-phase inverter)
12a, 12b, 22a, 22b DC capacitors 13a, 13b, 23a, 23b AC reactor 14 Current sensors 16, 26 DC switches 17, 27 AC capacitors 18, 18-1 to 18-n, 28, 28-1 to 28- m DC fuse (protective device)
30 Open delta connection transformers 31u, 31v, 31w Primary windings 32u, 32v, 32w Secondary windings 40 Control device 50 Photovoltaic power generation equipment 51 First photovoltaic power generation equipment 52 Second photovoltaic power generation equipment 51-1 ~ 51-n, 52-1 to 52-m solar cell group 60 storage battery equipment 61 first storage battery 62 second storage battery 101, 102 power conversion system

Claims (7)

  1. 　太陽光発電設備から供給される直流電力を３相交流電力に変換する電力変換システムであって、
    　交流電力系統に接続された単一のオープンデルタ結線変圧器と、
    　並列に接続された複数の３相インバータを有し、複数の前記３相インバータの入力端子に直流コンデンサが並列に接続されて構成された第１多重インバータ装置と、
    　並列に接続された複数の３相インバータを有し、複数の前記３相インバータの入力端子に直流コンデンサが並列に接続されて構成された第２多重インバータ装置と、を備え、
    　前記太陽光発電設備は、
    　　複数の太陽電池群が並列に接続されてなる第１太陽光発電設備と、
    　　複数の太陽電池群が並列に接続されてなる第２太陽光発電設備と、を有し、
    　前記第１多重インバータ装置は、
    　　前記第１太陽光発電設備に接続された入力部と、
    　　前記オープンデルタ結線変圧器の各相の１次巻線の一端に接続された出力部と、を備え、
    　前記第２多重インバータ装置は、
    　　前記第２太陽光発電設備に接続された入力部と、
    　　前記オープンデルタ結線変圧器の各相の前記１次巻線の他端に接続された出力部と、を備える
    ことを特徴とする電力変換システム。     A power conversion system that converts DC power supplied from a photovoltaic power generation facility into three-phase AC power,
    A single open delta connected transformer connected to the AC power system;
    a first multiplex inverter device having a plurality of three-phase inverters connected in parallel and configured by connecting DC capacitors in parallel to input terminals of the plurality of three-phase inverters;
    a second multiple inverter device having a plurality of three-phase inverters connected in parallel, and configured by connecting DC capacitors in parallel to input terminals of the plurality of three-phase inverters;
    The solar power generation facility is
    a first solar power generation facility in which a plurality of solar cell groups are connected in parallel;
    a second solar power generation facility in which a plurality of solar cell groups are connected in parallel;
    The first multiple inverter device
    an input unit connected to the first photovoltaic power generation facility;
    an output unit connected to one end of the primary winding of each phase of the open delta connection transformer,
    The second multiple inverter device is
    an input unit connected to the second photovoltaic power generation facility;
    and an output unit connected to the other end of the primary winding of each phase of the open delta connection transformer.
  2. 　請求項１に記載の電力変換システムにおいて、
    　前記第１多重インバータ装置は、複数の前記３相インバータの出力端子が共通相ごとに交流リアクトルを介して相互に接続されて構成され、
    　前記第２多重インバータ装置は、複数の前記３相インバータの出力端子が共通相ごとに交流リアクトルを介して相互に接続されて構成されている
    ことを特徴とする電力変換システム。     In the power conversion system according to claim 1,
    The first multiple inverter device is configured by connecting output terminals of the plurality of three-phase inverters to each other via an AC reactor for each common phase,
    A power conversion system, wherein the second multiple inverter device is configured such that the output terminals of the plurality of three-phase inverters are connected to each other via an AC reactor for each common phase.
  3. 　請求項１又は２に記載の電力変換システムにおいて、
    　前記第１多重インバータ装置の前記入力部と前記第１太陽光発電設備との間、及び前記第２多重インバータ装置の前記入力部と前記第２太陽光発電設備との間には、それぞれ、直流開閉器が設けられている
    ことを特徴とする電力変換システム。     In the power conversion system according to claim 1 or 2,
    Between the input section of the first multiple inverter device and the first photovoltaic power generation facility, and between the input section of the second multiple inverter device and the second photovoltaic power generation facility, respectively. A power conversion system comprising a switch.
  4. 　請求項１乃至３の何れか１項に記載の電力変換システムにおいて、
    　前記第１太陽光発電設備を構成する複数の前記太陽電池群、及び前記第２太陽光発電設備を構成する複数の前記太陽電池群には、それぞれ、短絡電流を遮断する保護機器が設けられている
    ことを特徴とする電力変換システム。     In the power conversion system according to any one of claims 1 to 3,
    The plurality of solar cell groups constituting the first solar power generation facility and the plurality of solar cell groups constituting the second solar power generation facility are each provided with a protection device that cuts off a short-circuit current. A power conversion system characterized by:
  5. 　請求項１乃至４の何れか１項に記載の電力変換システムにおいて、
    　前記第１多重インバータ装置の前記出力部と前記オープンデルタ結線変圧器との間、及び前記第２多重インバータ装置の前記出力部と前記オープンデルタ結線変圧器との間には、それぞれ、交流コンデンサが設けられている
    ことを特徴とする電力変換システム。     In the power conversion system according to any one of claims 1 to 4,
    AC capacitors are provided between the output section of the first multiple inverter device and the open delta connection transformer, and between the output section of the second multiple inverter device and the open delta connection transformer, respectively. A power conversion system characterized by being provided.
  6. 　請求項１乃至５の何れか１項に記載の電力変換システムにおいて、
    　前記第１多重インバータ装置と前記第２多重インバータ装置とを協調制御する制御装置を備え、
    　前記制御装置は、前記第１多重インバータ装置と前記第２多重インバータ装置とに符号が異なる電圧を出力させる
    ことを特徴とする電力変換システム。     In the power conversion system according to any one of claims 1 to 5,
    a control device that cooperatively controls the first multiple inverter device and the second multiple inverter device;
    The power conversion system, wherein the control device causes the first multiple inverter device and the second multiple inverter device to output voltages having different signs.
  7. 　第１直流電源と第２直流電源とから供給される直流電力を３相交流電力に変換する電力変換システムであって、
    　交流電力系統に接続された単一のオープンデルタ結線変圧器と、
    　並列に接続された複数の３相インバータを有し、複数の前記３相インバータの入力端子に直流コンデンサが並列に接続されて構成された第１多重インバータ装置と、
    　並列に接続された複数の３相インバータを有し、複数の前記３相インバータの入力端子に直流コンデンサが並列に接続されて構成された第２多重インバータ装置と、を備え、
    　前記第１多重インバータ装置は、
    　　前記第１直流電源に接続された入力部と、
    　　前記オープンデルタ結線変圧器の各相の１次巻線の一端に接続された出力部と、を備え、
    　前記第２多重インバータ装置は、
    　　前記第２直流電源に接続された入力部と、
    　　前記オープンデルタ結線変圧器の各相の前記１次巻線の他端に接続された出力部と、を備える
    ことを特徴とする電力変換システム。     A power conversion system for converting DC power supplied from a first DC power supply and a second DC power supply into three-phase AC power,
    A single open delta connected transformer connected to the AC power system;
    a first multiplex inverter device having a plurality of three-phase inverters connected in parallel and configured by connecting DC capacitors in parallel to input terminals of the plurality of three-phase inverters;
    a second multiple inverter device having a plurality of three-phase inverters connected in parallel, and configured by connecting DC capacitors in parallel to input terminals of the plurality of three-phase inverters;
    The first multiple inverter device
    an input unit connected to the first DC power supply;
    an output unit connected to one end of the primary winding of each phase of the open delta connection transformer,
    The second multiple inverter device is
    an input unit connected to the second DC power supply;
    and an output unit connected to the other end of the primary winding of each phase of the open delta connection transformer.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5120533A (en) * 1974-08-12 1976-02-18 Mitsubishi Electric Corp
JPH02193570A (en) * 1988-10-21 1990-07-31 Fuji Electric Co Ltd Control of inverter
JP3237983B2 (en) * 1994-01-28 2001-12-10 隆夫 川畑 Multiple inverter device
JP2014033519A (en) * 2012-08-02 2014-02-20 Mitsubishi Electric Corp Power conditioner
JP2017535237A (en) * 2014-10-27 2017-11-24 エスエムエイ ソーラー テクノロジー アクティエンゲゼルシャフトＳＭＡ Ｓｏｌａｒ Ｔｅｃｈｎｏｌｏｇｙ ＡＧ Combiner box with electric overcurrent protection

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5120533A (en) * 1974-08-12 1976-02-18 Mitsubishi Electric Corp
JPH02193570A (en) * 1988-10-21 1990-07-31 Fuji Electric Co Ltd Control of inverter
JP3237983B2 (en) * 1994-01-28 2001-12-10 隆夫 川畑 Multiple inverter device
JP2014033519A (en) * 2012-08-02 2014-02-20 Mitsubishi Electric Corp Power conditioner
JP2017535237A (en) * 2014-10-27 2017-11-24 エスエムエイ ソーラー テクノロジー アクティエンゲゼルシャフトＳＭＡ Ｓｏｌａｒ Ｔｅｃｈｎｏｌｏｇｙ ＡＧ Combiner box with electric overcurrent protection

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