WO2017212572A1 - Grid-connected inverter device - Google Patents

Grid-connected inverter device Download PDF

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Publication number
WO2017212572A1
WO2017212572A1 PCT/JP2016/067055 JP2016067055W WO2017212572A1 WO 2017212572 A1 WO2017212572 A1 WO 2017212572A1 JP 2016067055 W JP2016067055 W JP 2016067055W WO 2017212572 A1 WO2017212572 A1 WO 2017212572A1
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WO
WIPO (PCT)
Prior art keywords
short
gate pulse
circuit
diode
converter
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Application number
PCT/JP2016/067055
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French (fr)
Japanese (ja)
Inventor
一平 竹内
智 神戸
西尾　直樹
Original Assignee
三菱電機株式会社
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Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2018522224A priority Critical patent/JP6537723B2/en
Priority to PCT/JP2016/067055 priority patent/WO2017212572A1/en
Publication of WO2017212572A1 publication Critical patent/WO2017212572A1/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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • 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

Definitions

  • the present invention relates to a grid-connected inverter device linked to a commercial power system.
  • the grid-connected inverter device converts a DC voltage boosted in each of the plurality of boost chopper units that boosts the voltage output from each of the plurality of solar cells and the plurality of converter circuits into an AC voltage.
  • An inverter unit converts a DC voltage boosted in each of the plurality of boost chopper units that boosts the voltage output from each of the plurality of solar cells and the plurality of converter circuits into an AC voltage.
  • the converter circuit is configured by combining a switching element represented by a transistor, a reactor, a capacitor, and a diode.
  • a switching element represented by a transistor, a reactor, a capacitor, and a diode.
  • Patent Document 1 determines that the diode has a short-circuit fault by detecting that the input DC voltage has increased to the same value as the output voltage of the converter circuit, and stops the converter circuit. This prevents damage to the DC power supply or performance degradation.
  • the DC power source connected to the input side of the converter circuit is a solar cell
  • the number of solar cells connected in series varies depending on the shape of the roof of the house, so the voltage applied to each of the plurality of converter circuits is different. It becomes. More specifically, in a grid-connected inverter device including a plurality of sets of converter circuits from first to fourth converter circuits, the first input voltage applied to each of the first to third converter circuits is Assume that the diode of the fourth converter circuit is short-circuited when the second input voltage applied to the fourth converter circuit is smaller than the first input voltage. At this time, the output voltages of the first to third solar cell strings connected to the first to third converter circuits and the output voltage of the fourth solar cell string connected to the fourth converter circuit, respectively.
  • Patent Document 1 a reverse current is generated in the fourth solar cell string.
  • the conventional technique disclosed in Patent Document 1 is configured to detect a diode failure and stop the operation of the converter circuit. However, in the above-described event, the reverse current cannot be stopped, and the solar cell is stopped. May cause performance degradation or damage.
  • the present invention has been made in view of the above, and an object of the present invention is to obtain a grid-connected inverter device that can prevent performance degradation of a DC power supply.
  • the grid-connected inverter device of the present invention includes a plurality of converter circuits to which power output from each of a plurality of DC power supplies is input, and a plurality of converter circuits.
  • a short-circuit fault detection for detecting a short-circuit fault of a diode constituting each of a plurality of converter circuits comprising an inverter circuit for converting a DC voltage output from each into an AC voltage And a gate pulse command generation unit that outputs a gate pulse command for controlling the switching elements constituting each of the plurality of converter circuits when the short circuit failure detection unit detects a short circuit failure of the diode. It is characterized by that.
  • the grid-connected inverter device has an effect of preventing the performance deterioration of the DC power supply.
  • FIG. 1 The figure which shows the solar energy power generation system containing the grid connection inverter apparatus which concerns on Embodiment 1 of this invention.
  • Configuration diagram of converter control unit shown in FIG. The flowchart regarding the operation
  • FIG. 1 is a diagram showing a photovoltaic power generation system including a grid-connected inverter device according to Embodiment 1 of the present invention.
  • the solar power generation system 100 includes solar cell strings 1a, 1b, 1c, and 1d that are a plurality of DC power sources, and a grid-connected inverter device 3 to which the solar cell strings 1a, 1b, 1c, and 1d are connected.
  • the plurality of solar cell strings 1a, 1b, 1c, and 1d may be abbreviated as “a plurality of solar cell strings 1”.
  • Each of the plurality of solar cell strings 1 has a configuration in which a plurality of solar cell modules (not shown) are connected in series, and generates DC power corresponding to the amount of solar radiation.
  • the grid interconnection inverter device 3 includes a converter control unit 16.
  • the converter control unit 16 generates a gate pulse command Gs for controlling each of the plurality of converter circuits 4a, 4b, 4c, 4d, and each of the plurality of gate pulse generators 17a, 17b, 17c, 17d. Output.
  • the grid-connected inverter device 3 is characterized in the operation of the gate pulse command Gs by the converter control unit 16.
  • the plurality of converter circuits 4a, 4b, 4c, 4d may be abbreviated as “a plurality of converter circuits 4”.
  • the plurality of gate pulse generators 17a, 17b, 17c, and 17d may be abbreviated as “a plurality of gate pulse generators 17”.
  • the grid interconnection inverter device 3 includes a plurality of positive input terminals 101a, 101b, 101c, 101d, a plurality of negative input terminals 102a, 102b, 102c, 102d, and system output terminals 103, 104.
  • the positive electrode output terminal of the solar cell string 1a is connected to the positive electrode input terminal 101a, and the negative electrode output terminal of the solar cell string 1a is connected to the negative electrode input terminal 102a.
  • the positive electrode output terminals of the solar cell strings 1b, 1c, and 1d are connected to the positive electrode input terminals 101b, 101c, and 101d, respectively.
  • the negative electrode output terminals of the solar cell strings 1b, 1c, and 1d are connected to the negative electrode input terminals 102b, 102c, and 102d, respectively.
  • Two system connection lines connected to the commercial power system 2 are connected to the system output terminals 103 and 104.
  • the grid interconnection inverter device 3 includes a plurality of smoothing capacitors 7a, 7b, 7c, and 7d, a plurality of converter circuits 4, a smoothing capacitor 8, an inverter circuit 5, and an output relay 6.
  • the smoothing capacitor 7a smoothes the DC voltage output from the solar cell string 1a and input to the converter circuit 4a.
  • One end of the smoothing capacitor 7a is connected to the positive electrode input terminal 101a and the positive electrode input terminal of the converter circuit 4a via the positive-polarity DC bus P.
  • the other end of the smoothing capacitor 7a is connected to the negative input terminal 102a and the negative input end of the converter circuit 4a via a negative DC bus N.
  • the converter circuit 4a includes a reactor 9a, a switching element 10a, and a diode 11a.
  • One end of the reactor 9a is a positive input terminal of the converter circuit 4a.
  • One end of the reactor 9a is connected to the positive electrode input terminal 101a and one end of the smoothing capacitor 7a.
  • the other end of the reactor 9a is connected to the anode of the diode 11a and the collector of the switching element 10a.
  • the cathode of the diode 11a is the positive output terminal of the converter circuit 4a.
  • the cathode of the diode 11 a is connected to one end of the smoothing capacitor 8 and the positive input terminal of the inverter circuit 5.
  • the emitter of the switching element 10a is connected to the other end of the smoothing capacitor 7a and the other end of the smoothing capacitor 8.
  • the gate pulse signal 17a1 output from the gate pulse generator 17a is input to the gate of the switching element 10a.
  • the gate pulse signal 17a1 is a signal for boosting the voltage output from the solar cell string 1a to a voltage necessary for the inverter circuit 5 to generate an AC voltage, or the diode 11a shorts the switching element 10a when a short circuit failure is detected. Signal.
  • the gate pulse generator 17a outputs a gate pulse signal 17a1 to the switching element 10a based on the gate pulse command Gs input from the converter control unit.
  • the smoothing capacitor 7b smoothes the DC voltage output from the solar cell string 1b and input to the converter circuit 4b.
  • One end of the smoothing capacitor 7b is connected to the positive electrode input terminal 101b and the positive electrode input terminal of the converter circuit 4b via the positive DC bus P.
  • the other end of the smoothing capacitor 7b is connected to the negative input terminal 102b and the negative input end of the converter circuit 4b via a negative DC bus N.
  • the converter circuit 4b includes a reactor 9b, a switching element 10b, and a diode 11b.
  • One end of the reactor 9b is a positive input terminal of the converter circuit 4b.
  • One end of the reactor 9b is connected to the positive electrode input terminal 101b and one end of the smoothing capacitor 7b.
  • the other end of the reactor 9b is connected to the anode of the diode 11b and the collector of the switching element 10b.
  • the cathode of the diode 11b is the positive output terminal of the converter circuit 4b.
  • the cathode of the diode 11 b is connected to one end of the smoothing capacitor 8 and the positive input terminal of the inverter circuit 5.
  • the emitter of the switching element 10b is connected to the other end of the smoothing capacitor 7b and the other end of the smoothing capacitor 8.
  • the gate pulse signal 17b1 output from the gate pulse generator 17b is input to the gate of the switching element 10b.
  • the gate pulse signal 17b1 is a signal for boosting the voltage output from the solar cell string 1b to a voltage necessary for the inverter circuit 5 to generate an AC voltage, and the diode 11b short-circuits the switching element 10b when a short circuit failure is detected. is there.
  • the gate pulse generator 17b outputs a gate pulse signal 17b1 to the switching element 10b based on the gate pulse command Gs input from the converter control unit.
  • the smoothing capacitor 7c smoothes the DC voltage output from the solar cell string 1c and input to the converter circuit 4c.
  • One end of the smoothing capacitor 7c is connected to the positive input terminal 101c and the positive input end of the converter circuit 4c via the positive DC bus P.
  • the other end of the smoothing capacitor 7c is connected to the negative input terminal 102c and the negative input end of the converter circuit 4c through a negative DC bus N.
  • the converter circuit 4c includes a reactor 9c, a switching element 10c, and a diode 11c.
  • One end of the reactor 9c is a positive input terminal of the converter circuit 4c.
  • One end of the reactor 9c is connected to the positive electrode input terminal 101c and one end of the smoothing capacitor 7c.
  • the other end of the reactor 9c is connected to the anode of the diode 11c and the collector of the switching element 10c.
  • the cathode of the diode 11c is a positive output terminal of the converter circuit 4c.
  • the cathode of the diode 11 c is connected to one end of the smoothing capacitor 8 and the positive input terminal of the inverter circuit 5.
  • the emitter of the switching element 10c is connected to the other end of the smoothing capacitor 7c and the other end of the smoothing capacitor 8.
  • the gate pulse signal 17c1 output from the gate pulse generator 17c is input to the gate of the switching element 10c.
  • the gate pulse signal 17c1 is a signal that boosts the voltage output from the solar cell string 1c to a voltage necessary for the inverter circuit 5 to generate an AC voltage, and the diode 11c shorts the switching element 10c when a short circuit failure is detected. is there.
  • the gate pulse generator 17c outputs a gate pulse signal 17c1 to the switching element 10c based on the gate pulse command Gs input from the converter control unit.
  • the smoothing capacitor 7d smoothes the DC voltage output from the solar cell string 1d and input to the converter circuit 4d.
  • One end of the smoothing capacitor 7d is connected to the positive input terminal 101d and the positive input terminal of the converter circuit 4d via the positive DC bus P.
  • the other end of the smoothing capacitor 7d is connected to the negative input terminal 102d and the negative input end of the converter circuit 4d via a negative DC bus N.
  • the converter circuit 4d includes a reactor 9d, a switching element 10d, and a diode 11d.
  • One end of the reactor 9d is a positive input terminal of the converter circuit 4d.
  • One end of the reactor 9d is connected to the positive electrode input terminal 101d and one end of the smoothing capacitor 7d.
  • the other end of the reactor 9d is connected to the anode of the diode 11d and the collector of the switching element 10d.
  • the cathode of the diode 11d is the positive output terminal of the converter circuit 4d.
  • the cathode of the diode 11 d is connected to one end of the smoothing capacitor 8 and the positive input terminal of the inverter circuit 5.
  • the emitter of the switching element 10d is connected to the other end of the smoothing capacitor 7d and the other end of the smoothing capacitor 8.
  • the gate pulse signal 17d1 output from the gate pulse generator 17d is input to the gate of the switching element 10d.
  • the gate pulse signal 17d1 is a signal for boosting the voltage output from the solar cell string 1d to a voltage necessary for the inverter circuit 5 to generate an AC voltage, and the diode 11d short-circuits the switching element 10d when a short-circuit fault is detected. is there.
  • the gate pulse generator 17d outputs a gate pulse signal 17d1 to the switching element 10d based on the gate pulse command Gs input from the converter control unit.
  • One end of the smoothing capacitor 8 is connected to the cathodes of the plurality of diodes 11 a, 11 b, 11 c, and 11 d and the positive input terminal of the inverter circuit 5.
  • the other end of the smoothing capacitor 8 is connected to the anodes of the plurality of diodes 11 a, 11 b, 11 c, 11 d and the negative input terminal of the inverter circuit 5.
  • the smoothing capacitor 8 smoothes the DC voltage output from each of the plurality of converter circuits 4 and input to the inverter circuit 5.
  • the inverter circuit 5 operates to convert the charging voltage of the smoothing capacitor 8 into an AC voltage.
  • the AC output terminal of the inverter circuit 5 is connected to the system output terminals 103 and 104 via the output relay 6.
  • the output relay 6 is disposed between the inverter circuit 5 and the two system output terminals 103 and 104.
  • the output relay 6 has a function of opening and closing a connection path between the inverter circuit 5 and the commercial power system 2.
  • the grid interconnection inverter device 3 includes a plurality of current detectors 12a, 12b, 12c, and 12d and a plurality of voltage detectors 13a, 13b, 13c, and 13d.
  • the plurality of current detectors 12 a, 12 b, 12 c, 12 d, the plurality of voltage detectors 13 a, 13 b, 13 c, 13 d, and the converter control unit 16 constitute a control unit 200 of the grid interconnection inverter device 3.
  • the control unit 200 is used to drive a plurality of converter circuits 4. Specifically, the control unit 200 generates a gate pulse command determined by MPPT (Maximum Power Point Tracking) control, which is maximum power tracking control that causes the operating points of the plurality of solar cell strings 1 to follow the maximum power point. .
  • MPPT Maximum Power Point Tracking
  • the control unit 200 detects a short-circuit failure of the diodes 11a, 11b, 11c, and 11d that configure each of the plurality of converter circuits 4
  • the switching elements 10a, 10b, and 10c that configure each of the plurality of converter circuits 4 Gate pulse signals 17a1, 17b1, 17c1, and 17d1 that short-circuit 10d are generated.
  • switching elements 10a, 10b, 10c, and 10d shown in FIG. 1 are IGBTs (Insulated Gate Bipolar Transistors), but transistors other than IGBTs may be used.
  • IGBTs Insulated Gate Bipolar Transistors
  • MOSFET Metal-Oxide-Semiconductor Field-Effect Transistor
  • converter circuits 4a, 4b, 4c, and 4d are used, but the number of converter circuits may be two or more.
  • an example of the converter circuits 4a, 4b, 4c, and 4d is shown, but the configuration of the converter circuit is not limited to the illustrated example, and the switching elements 10a, 10b, 10c, and 10d and the diodes 11a, 11b, 11c, Other power conversion circuits may be used as long as the power conversion circuit converts the DC voltage into a desired DC voltage value using 11d.
  • FIG. 1 four solar cell strings 1a, 1b, 1c, and 1d are connected to the grid interconnection inverter device 3.
  • the number of solar cell strings connected is not limited to the illustrated example, and two or more solar cell strings are connected. I just need it.
  • the photovoltaic power generation system 100 uses a number of converter circuits 4 corresponding to the number of solar cell strings.
  • control unit 200 the configuration of the control unit 200 will be specifically described.
  • a current detection element 30a is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102a and the converter circuit 4a.
  • the current detection element 30a detects a current value at the position.
  • a current transformer or a shunt resistor is used for the current detection element 30a.
  • the current detector 12a is realized by an amplifier or a level shift circuit, and converts a voltage directly proportional to the current detected by the current detection element 30a into a current detection voltage within a low voltage range that can be handled by the power calculator 14a and outputs the voltage. To do.
  • This current detection voltage corresponds to the current value Isa of the output current of the solar cell string 1a.
  • the current value Isa output from the current detector 12 a is input to the converter control unit 16.
  • One end of the voltage detector 13a is connected to the positive electrode input terminal 101a, one end of the reactor 9a, and one end of the smoothing capacitor 7a in the DC bus P on the positive electrode side.
  • the other end of the voltage detector 13a is connected to the negative input terminal 102a and the other end of the smoothing capacitor 7a on the negative DC bus N.
  • the voltage detector 13a detects the voltage value Vsa which is the output voltage value of the solar cell string 1a.
  • the voltage value Vsa output from the voltage detector 13a is input to the converter control unit 16.
  • a current detection element 30b is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102b and the converter circuit 4b.
  • the current detection element 30b detects a current value at the position.
  • a current transformer or a shunt resistor is used for the current detection element 30b.
  • the current detector 12b is realized by an amplifier or a level shift circuit, and converts a voltage directly proportional to the current detected by the current detection element 30b into a current detection voltage within a low voltage range that can be handled by the power calculator 14b and outputs the voltage. To do.
  • This current detection voltage corresponds to the current value Isb of the output current of the solar cell string 1b.
  • the current value Isb output from the current detector 12 b is input to the converter control unit 16.
  • One end of the voltage detector 13b is connected to the positive electrode input terminal 101b, one end of the reactor 9b, and one end of the smoothing capacitor 7b in the DC bus P on the positive electrode side.
  • the other end of the voltage detector 13b is connected to the negative input terminal 102b and the other end of the smoothing capacitor 7b on the negative DC bus N.
  • the voltage detector 13b detects a voltage value Vsb that is an output voltage value of the solar cell string 1b.
  • the voltage value Vsb output from the voltage detector 13b is input to the converter control unit 16.
  • a current detection element 30c is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102c and the converter circuit 4c.
  • the current detection element 30c detects a current value at the position.
  • a current transformer or a shunt resistor is used for the current detection element 30c.
  • the current detector 12c is realized by an amplifier or a level shift circuit, and converts a voltage directly proportional to the current detected by the current detection element 30c into a current detection voltage within a low voltage range that can be handled by the power calculator 14c and outputs the voltage. To do.
  • This current detection voltage corresponds to the current value Isc of the output current of the solar cell string 1c.
  • the current value Isc output from the current detector 12 c is input to the converter control unit 16.
  • One end of the voltage detector 13c is connected to the positive electrode input terminal 101c, one end of the reactor 9c, and one end of the smoothing capacitor 7c in the DC bus P on the positive electrode side.
  • the other end of the voltage detector 13c is connected to the negative input terminal 102c and the other end of the smoothing capacitor 7c in the negative DC bus N.
  • the voltage detector 13c detects a voltage value Vsc that is an output voltage value of the solar cell string 1c.
  • the voltage value Vsc output from the voltage detector 13 c is input to the converter control unit 16.
  • a current detection element 30d is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102d and the converter circuit 4d.
  • the current detection element 30d detects a current value at the position.
  • a current transformer or a shunt resistor is used for the current detection element 30d.
  • the current detector 12d is realized by an amplifier or a level shift circuit, and converts a voltage directly proportional to the current detected by the current detection element 30d into a current detection voltage within a low voltage range that can be handled by the power calculator 14d and outputs the voltage. To do.
  • This current detection voltage corresponds to the current value Isd of the output current of the solar cell string 1d.
  • the current value Isd output from the current detector 12 d is input to the converter control unit 16.
  • One end of the voltage detector 13d is connected to the positive electrode input terminal 101d, one end of the reactor 9d, and one end of the smoothing capacitor 7d on the DC bus P on the positive electrode side.
  • the other end of the voltage detector 13d is connected to the negative input terminal 102d and the other end of the smoothing capacitor 7d on the negative DC bus N.
  • the voltage detector 13d detects a voltage value Vsd that is an output voltage value of the solar cell string 1d.
  • the voltage value Vsd output from the voltage detector 13d is input to the converter control unit 16.
  • the converter control unit 16 generates a gate pulse command Gs for operating the plurality of converter circuits 4 based on the plurality of current values Isa, Isb, Isc, Isd and the plurality of voltage values Vsa, Vsb, Vsc, Vsd. Then, it outputs to a plurality of gate pulse generators 17.
  • the converter control unit 16 determines whether or not any of the diodes 11a, 11b, 11c, and 11d constituting each of the plurality of converter circuits 4 is short-circuited, that is, the diodes 11a, 11b, 11c, and 11d. The presence or absence of any short-circuit failure is determined. Moreover, the converter control part 16 produces
  • FIG. 2 is a block diagram of the converter control unit 16 shown in FIG.
  • the converter control unit 16 shown in FIG. 2 includes a short-circuit fault detection unit 20, an MPPT control unit 21, and a gate pulse command generation unit 22.
  • the short-circuit fault detection unit 20 inputs the current values Isa, Isb, Isc, Isd detected by the plurality of current detectors 12a, 12b, 12c, 12d, and a plurality of converter circuits based on the current values Isa, Isb, Isc, Isd. 4 is determined whether or not there is a short circuit fault in any of the diodes 11a, 11b, 11c, and 11d constituting each of the four.
  • the short-circuit fault detection unit 20 determines that no short-circuit fault has occurred in any of the diodes 11a, 11b, 11c, and 11d based on the following equation (1), and the diodes 11a, 11b, It is determined that a short circuit failure has occurred in either 11c or 11d. Then, the short-circuit fault detection unit 20 outputs a determination result 20 a indicating the presence or absence of a short-circuit fault to the gate pulse command generation unit 22.
  • the converter control unit 16 of the grid-connected inverter device 3 determines the direction of the current flowing between the solar cell and the grid-connected inverter device 3. It is comprised so that the presence or absence of a short circuit failure may be determined.
  • the MPPT control unit 21 includes current values Isa, Isb, Isc, Isd detected by the plurality of current detectors 12a, 12b, 12c, 12d, and voltages detected by the plurality of voltage detectors 13a, 13b, 13c, 13d.
  • the values Vsa, Vsb, Vsc, and Vsd are input, the first gate pulse command 21a determined by the MPPT control is generated, and is output to the gate pulse command generation unit 22.
  • the MPPT control for detecting the maximum power point of the solar cell string is performed by a generally well-known hill-climbing method. Since various methods have been proposed for MPPT control, control other than hill climbing may be performed. Since the output characteristics of solar cells have a maximum power point, the hill-climbing method is a method that estimates the direction of the maximum point by increasing or decreasing the power of the solar cell and detects the maximum point by gradually changing the voltage and current. is there.
  • the gate pulse command generation unit 22 receives the determination result 20a indicating the presence or absence of a short-circuit failure output from the short-circuit failure detection unit 20 and the first gate pulse command 21a output from the MPPT control unit 21, and the determination result The presence or absence of a short circuit failure is determined based on 20a. Then, the gate pulse command generation unit 22 outputs the first gate pulse command 21a described above as the gate pulse command Gs to the gate pulse generators 17a, 17b, 17c, and 17d according to the determination result of the short circuit failure, or the gate A second gate pulse command 22a generated by the pulse command generator 22 is generated and output to the gate pulse generators 17a, 17b, 17c, and 17d as the gate pulse command Gs.
  • the gate pulse command generation unit 22 that has determined that a short circuit failure has not occurred based on the determination result 20a generates a gate pulse using the first gate pulse command 21a output from the MPPT control unit 21 as the gate pulse command Gs.
  • the gate pulse command generator 22 that has determined that a short-circuit failure has occurred based on the determination result 20a generates a second gate pulse command 22a that short-circuits all the switching elements 10a, 10b, 10c, and 10d of the plurality of converter circuits 4.
  • the second gate pulse command 22a is output to the gate pulse generators 17a, 17b, 17c and 17d as the gate pulse command Gs.
  • the converter control unit 16 prevents all the switching elements 10a, 10b, 10c, and the like constituting each of the plurality of converter circuits 4 from flowing a reverse current to the solar cell string connected to the converter circuit in which the diode is short-circuited.
  • the plurality of solar cell strings 1 are all short-circuited. Thereby, it can prevent that a reverse current flows into the solar cell string connected to the converter circuit in which the diode short-circuited.
  • FIG. 3 is a flowchart relating to the operation at the time of determining a diode short-circuit fault by the converter control unit of the grid-connected inverter device according to the first embodiment of the present invention.
  • the short-circuit fault detection unit 20 inputs the current values Isa, Isb, Isc, Isd detected by the plurality of current detectors 12a, 12b, 12c, 12d.
  • the short-circuit fault detection unit 20 determines whether or not the diode 11a of the converter circuit 4a has a short-circuit fault by the following equation (3).
  • the short-circuit fault detector 20 determines that the diode 11a of the converter circuit 4a has a short-circuit fault, and determines the determination result 20a. Output to the gate pulse command generator 22.
  • the short circuit failure detection unit 20 determines whether or not the diode 11b of the converter circuit 4b has a short circuit failure according to the following equation (4). Isb ⁇ 0 [A] (4)
  • the short-circuit fault detection unit 20 determines that the diode 11b of the converter circuit 4b has a short-circuit fault, and determines the determination result 20a. Output to the gate pulse command generator 22.
  • the short circuit failure detection unit 20 determines whether or not the diode 11c of the converter circuit 4c has a short circuit failure according to the following equation (5).
  • the short-circuit fault detection unit 20 determines that the diode 11c of the converter circuit 4c is normal and uses the determination result 20a as a gate pulse command. Output to the generation unit 22.
  • the short-circuit fault detector 20 determines that the diode 11c of the converter circuit 4c has a short-circuit fault, and determines the determination result 20a. Output to the gate pulse command generator 22.
  • the short circuit failure detection unit 20 determines whether or not the diode 11d of the converter circuit 4d has a short circuit failure according to the following equation (6).
  • the short-circuit fault detection unit 20 determines that the diode 11d of the converter circuit 4d is normal and uses the determination result 20a as a gate pulse command. Output to the generation unit 22.
  • the short-circuit fault detection unit 20 determines that the diode 11d of the converter circuit 4d has a short-circuit fault, and determines the determination result 20a. Output to the gate pulse command generator 22.
  • the MPPT control unit 21 calculates the first gate pulse command 21a determined by the MPPT control.
  • the gate pulse command generation unit 22 determines the presence or absence of a short circuit failure of the diode based on the determination result 20a output from the short circuit failure detection unit 20 in S2 to S12.
  • the gate pulse command generation unit 22 is a second gate pulse command that is a switching element short-circuit command that short-circuits all the switching elements 10a, 10b, 10c, and 10d. 22a is generated and output as a gate pulse command Gs to each of the plurality of gate pulse generators 17a, 17b, 17c, and 17d.
  • the gate pulse command generation unit 22 selects the first gate pulse command 21a calculated in S14, and generates a plurality of gate pulses as the gate pulse command Gs. Output to each of the devices 17a, 17b, 17c, 17d.
  • the plurality of gate pulse generators 17a, 17b, 17c, and 17d generate gate pulse signals 17a1, 17b1, 17c1, and 17d1 corresponding to the type of the received gate pulse command Gs. That is, in the case of the gate pulse command Gs corresponding to the first gate pulse command 21a, the gate pulse signals 17a1, 17b1, 17c1, and 17d1 for boosting the voltage output from the solar cell string 1a are generated.
  • the gate pulse command Gs corresponds to the second gate pulse command 22a
  • gate pulse signals 17a1, 17b1, 17c1, and 17d1 that short-circuit all the switching elements 10a, 10b, 10c, and 10d are generated.
  • the MPPT controller 21 calculates the first gate pulse command 21a in S14.
  • the gate pulse command generation unit 22 outputs the second gate pulse command 22a that short-circuits all the switching elements 10a, 10b, 10c, and 10d of the plurality of converter circuits 4 as the gate pulse command Gs.
  • the grid-connected inverter device 3 of the first embodiment determines whether or not the respective diodes 11a, 11b, 11c, and 11d of the converter circuits 4a, 4b, 4c, and 4d are short-circuited.
  • a gate pulse command for the converter circuit corresponding to the control command of the MPPT control unit 21 is output.
  • a gate pulse command for short-circuiting the switching element of the converter circuit is output. It is configured to output.
  • Embodiment 2 shows a short-circuit fault, when the diode detects a short-circuit fault, all the switching elements of the converter circuit are short-circuited, all the plurality of solar cell strings 1 are short-circuited, and the diode is short-circuit fault The reverse current does not flow through the solar cell string connected to the converter circuit.
  • the grid-connected inverter device 3 according to the second embodiment short-circuits the switching element that constitutes the converter circuit including the short-circuited diode, thereby bringing the solar cell string connected to the converter circuit into a short-circuited state, thereby causing a short-circuit fault.
  • a reverse current does not flow through the solar cell string connected to the converter circuit including the non-connected diode.
  • the configuration of the grid interconnection inverter device 3 according to the second embodiment is the same as that of the grid interconnection inverter device 3 according to the first embodiment except for the operation in the converter control unit 16, and thus the description thereof is omitted.
  • FIG. 4 is a flowchart relating to the operation at the time of determining a diode short-circuit fault by the converter control unit of the grid-connected inverter device according to the second embodiment of the present invention.
  • the difference from the flowchart shown in FIG. 3 is that the processes of S16 and S18 are replaced with the processes of S26 and S28.
  • a short circuit failure occurs in the diode 11a that constitutes the converter circuit 4a, and the diodes 11b, 11c, and 11b that constitute the converter circuits 4b, 4c, and 4d, It is assumed that no short circuit fault has occurred in 11d.
  • the gate pulse command generation unit 22 When there is a short circuit fault in the diode 11a (S15, Yes), the gate pulse command generation unit 22 generates a second gate pulse command 22a that is a switching element short circuit command for short-circuiting the switching element 10a.
  • the command Gs is output to the gate pulse generator 17a.
  • the gate pulse generator 17a that has received the gate pulse command Gs generates a gate pulse signal 17a1 for short-circuiting the switching element 10a.
  • the solar cell string 1a connected to the converter circuit 4a including the short-circuited diode 11a is short-circuited. Furthermore, the current output from the solar cell strings 1b, 1c, 1d connected to the converter circuits 4b, 4c, 4d having normal diodes flows to the switching element 10a constituting the converter circuit 4a having the short-circuited diode 11a. Therefore, no reverse current flows through the solar cell strings 1b, 1c, 1d. Therefore, the performance deterioration or damage of the solar cell can be prevented.
  • the converter control unit is compared with the first embodiment.
  • the generation operation of the gate pulse command Gs by 16 can be simplified.
  • the grid connection inverter apparatus 3 which concerns on Embodiment 2 is set as the structure which short-circuits only the switching element of a converter circuit provided with the short-circuited diode
  • the switching element to be short-circuited is switching of the converter circuit provided with the short-circuited diode The same effect can be obtained even if one or more switching elements of a converter circuit including a diode that is not short-circuited are included.
  • Embodiment 3 FIG.
  • the drive power of the equipment constituting the grid interconnection inverter device 3 is generated by the power supplied from the commercial power grid 2.
  • the DC power source connected to the grid-connected inverter device 3 is the solar cell string 1
  • the driving power of the equipment constituting the grid-connected inverter device 3 is generated by the power supplied from the solar cell string 1. Is common.
  • the grid interconnection inverter device 3 according to Embodiment 3 prevents the reverse current by the operation described below in the configuration in which the driving power is generated by the power generated by the plurality of solar cell strings 1.
  • the configuration of the grid interconnection inverter device 3 according to the third embodiment is the same as that of the grid interconnection inverter device 3 according to the first embodiment except for the operation in the converter control unit 16, and thus the description thereof is omitted.
  • FIG. 5 is a flowchart relating to the operation at the time of determining a diode short-circuit fault by the converter control unit of the grid-connected inverter device according to the third embodiment of the present invention.
  • the difference from the flowchart shown in FIG. 3 is that the processes of S16 and S18 are replaced with the processes of S36 and S28.
  • a short circuit fault occurs in the diode 11a that constitutes the converter circuit 4a, and the diodes 11b, 11c, and 11b that constitute the converter circuits 4b, 4c, and 4d, It is assumed that no short circuit fault has occurred in 11d.
  • the gate pulse command generation unit 22 is a switching element that constitutes the converter circuits 4b, 4c, and 4d including the diodes 11b, 11c, and 11d that are not short-circuited.
  • a second gate pulse command 22a which is a switching element short-circuit command for short-circuiting 10b, 10c, and 10d, is generated and output as a gate pulse command Gs to each of the gate pulse generators 17b, 17c, and 17d.
  • Each of the gate pulse generators 17b, 17c, 17d receiving the gate pulse command Gs generates and outputs a gate pulse signal corresponding to the type of the received gate pulse command Gs. That is, in the case of the gate pulse command Gs corresponding to the first gate pulse command 21a, the gate pulse signals 17b1, 17c1, and 17d1 that boost the voltage output from the solar cell strings 1b, 1c, and 1d are output.
  • the gate pulse command Gs corresponds to the second gate pulse command 22a
  • a gate pulse signal 17a1 for short-circuiting the switching elements 10b, 10c, and 10d is generated.
  • the output voltage of the solar cell string 1a is reduced.
  • the diode 11a since the diode 11a is normal, the current output from the solar cell string 1a is blocked. Is done. Therefore, the reverse current to the solar cell string 1a does not occur, and the driving power can be generated by the power supplied from the solar cell string 1a.
  • the grid interconnection inverter device 3 even when the components of the grid interconnection inverter device 3 are driven by the power of the solar cell string, the short circuit state of the switching element can be maintained. The performance deterioration or damage of the solar cell can be prevented.
  • MOSFET comprised using silicon carbide (Silicon Carbide: SiC) as switching element 10a, 10b, 10c, 10d with which the grid connection inverter apparatus 3 which concerns on Embodiment 1-3 is equipped. Since a current flows through the switching element in which a short-circuit fault of the diode is detected and short-circuited, heat is generated due to a loss due to the ON resistance of the switching element. By using MOSFETs made of silicon carbide as the switching elements 10a, 10b, 10c, and 10d, the ON resistance can be lowered and heat generation can be suppressed.
  • SiC silicon carbide
  • a radiator (not shown) connected to each of the converter circuits 4a, 4b, 4c, 4d can be reduced in size, and the weight of the grid interconnection inverter device 3 can be reduced. Can be lightened.
  • the configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

Abstract

A grid-connected inverter device 3 is characterized by being provided with: a plurality of converter circuits 4a, 4b, 4c, 4d for receiving powers respectively output from a plurality of DC power supplies; an inverter circuit 5 for converting DC voltages output from the respective converter circuits 4a, 4b, 4c, 4d to AC voltages; a short-circuit failure detection unit for detecting short-circuit failures of diodes constituting the respective converter circuits 4a, 4b, 4c, 4d; and a gate pulse command generation unit for, when the short-circuit failure detection unit detects the short-circuit failures of the diodes, outputting a gate pulse command for controlling switching elements constituting the respective converter circuits 4a, 4b, 4c, 4d.

Description

系統連系インバータ装置Grid-connected inverter device
　本発明は、商用電力系統に連系される系統連系インバータ装置に関する。 The present invention relates to a grid-connected inverter device linked to a commercial power system.
　系統連系インバータ装置は、複数の太陽電池のそれぞれから出力される電圧を昇圧する複数の昇圧チョッパ部であるコンバータ回路と、複数のコンバータ回路のそれぞれにおいて昇圧された直流電圧を交流電圧に変換するインバータ部とを備える。 The grid-connected inverter device converts a DC voltage boosted in each of the plurality of boost chopper units that boosts the voltage output from each of the plurality of solar cells and the plurality of converter circuits into an AC voltage. An inverter unit.
　コンバータ回路は、トランジスタを代表とするスイッチング素子とリアクトルとコンデンサとダイオードとを組み合わせて構成される。このように構成されるコンバータ回路が複数組並列に接続されている場合、複数のコンバータ回路の内、一部のコンバータ回路を構成するダイオードに異常が生じて短絡故障が発生したとき、出力側に接続される別のコンバータ回路の直流電源から入力側、すなわち直流電源側に電流が逆流する。このような逆流電流が太陽電池を代表とする直流電源に入力されると、直流電源の破損または性能劣化を引き起こすおそれがある。 The converter circuit is configured by combining a switching element represented by a transistor, a reactor, a capacitor, and a diode. When multiple sets of converter circuits configured in this way are connected in parallel, when a short circuit failure occurs due to an abnormality in the diodes that make up some of the converter circuits, A current flows backward from the DC power supply of another connected converter circuit to the input side, that is, the DC power supply side. When such a backflow current is input to a DC power source typified by a solar cell, the DC power source may be damaged or performance may be deteriorated.
　特許文献１に開示される従来技術は、入力される直流電圧がコンバータ回路の出力電圧と同じ値まで上昇したことを検出することにより、ダイオードが短絡故障したと判定し、コンバータの回路を停止することで直流電源の破損または性能劣化を防止している。 The prior art disclosed in Patent Document 1 determines that the diode has a short-circuit fault by detecting that the input DC voltage has increased to the same value as the output voltage of the converter circuit, and stops the converter circuit. This prevents damage to the DC power supply or performance degradation.
特許第５２７８８３７号公報Japanese Patent No. 5278837
　コンバータ回路の入力側に接続される直流電源が太陽電池の場合、直列に接続される太陽電池の枚数が住宅の屋根の形状により異なるため、複数のコンバータ回路のそれぞれに印加される電圧が異なる値となる。具体的に説明すると、第１から第４のコンバータ回路までの複数組みのコンバータ回路を備える系統連系インバータ装置において、第１から第３までコンバータ回路のそれぞれに印加される第１の入力電圧が同一であり、第４のコンバータ回路に印加される第２の入力電圧が第１の入力電圧よりも小さいときに第４のコンバータ回路のダイオードが短絡故障したとする。このとき、第１から第３までコンバータ回路のそれぞれに接続される第１から第３の太陽電池ストリングのそれぞれの出力電圧と第４のコンバータ回路に接続される第４の太陽電池ストリングの出力電圧との電圧差と、各太陽電池ストリングのダイオード特性とにより、第４の太陽電池ストリングに逆電流が生じる。特許文献１に開示される従来技術は、ダイオード故障を検出してコンバータ回路の動作を停止するように構成されているが、上述した事象においては、逆電流を停止することができず、太陽電池の性能劣化または破損を引き起こすおそれがある。 When the DC power source connected to the input side of the converter circuit is a solar cell, the number of solar cells connected in series varies depending on the shape of the roof of the house, so the voltage applied to each of the plurality of converter circuits is different. It becomes. More specifically, in a grid-connected inverter device including a plurality of sets of converter circuits from first to fourth converter circuits, the first input voltage applied to each of the first to third converter circuits is Assume that the diode of the fourth converter circuit is short-circuited when the second input voltage applied to the fourth converter circuit is smaller than the first input voltage. At this time, the output voltages of the first to third solar cell strings connected to the first to third converter circuits and the output voltage of the fourth solar cell string connected to the fourth converter circuit, respectively. And a diode characteristic of each solar cell string, a reverse current is generated in the fourth solar cell string. The conventional technique disclosed in Patent Document 1 is configured to detect a diode failure and stop the operation of the converter circuit. However, in the above-described event, the reverse current cannot be stopped, and the solar cell is stopped. May cause performance degradation or damage.
　本発明は、上記に鑑みてなされたものであって、直流電源の性能劣化を防止できる系統連系インバータ装置を得ることを目的とする。 The present invention has been made in view of the above, and an object of the present invention is to obtain a grid-connected inverter device that can prevent performance degradation of a DC power supply.
　上述した課題を解決し、目的を達成するために、本発明の系統連系インバータ装置は、複数の直流電源のそれぞれから出力される電力が入力される複数のコンバータ回路と、複数のコンバータ回路のそれぞれから出力される直流電圧を交流電圧へ変換するインバータ回路とを備えた系統連系インバータ装置であって、複数のコンバータ回路のぞれぞれを構成するダイオードの短絡故障を検出する短絡故障検出部と、短絡故障検出部がダイオードの短絡故障を検出したとき、複数のコンバータ回路のぞれぞれを構成するスイッチング素子を制御するためのゲートパルス指令を出力するゲートパルス指令生成部とを備えることを特徴とする。 In order to solve the above-described problems and achieve the object, the grid-connected inverter device of the present invention includes a plurality of converter circuits to which power output from each of a plurality of DC power supplies is input, and a plurality of converter circuits. A short-circuit fault detection for detecting a short-circuit fault of a diode constituting each of a plurality of converter circuits, comprising an inverter circuit for converting a DC voltage output from each into an AC voltage And a gate pulse command generation unit that outputs a gate pulse command for controlling the switching elements constituting each of the plurality of converter circuits when the short circuit failure detection unit detects a short circuit failure of the diode. It is characterized by that.
　本発明に係る系統連系インバータ装置は、直流電源の性能劣化を防止できるという効果を奏する。 The grid-connected inverter device according to the present invention has an effect of preventing the performance deterioration of the DC power supply.
本発明の実施の形態１に係る系統連系インバータ装置を含む太陽光発電システムを示す図The figure which shows the solar energy power generation system containing the grid connection inverter apparatus which concerns on Embodiment 1 of this invention. 図１に示すコンバータ制御部の構成図Configuration diagram of converter control unit shown in FIG. 本発明の実施の形態１に係る系統連系インバータ装置のコンバータ制御部によるダイオード短絡故障判定時の動作に係わるフローチャートThe flowchart regarding the operation | movement at the time of the diode short circuit failure determination by the converter control part of the grid connection inverter apparatus which concerns on Embodiment 1 of this invention. 本発明の実施の形態２に係る系統連系インバータ装置のコンバータ制御部によるダイオード短絡故障判定時の動作に係わるフローチャートThe flowchart regarding the operation | movement at the time of the diode short circuit failure determination by the converter control part of the grid connection inverter apparatus which concerns on Embodiment 2 of this invention. 本発明の実施の形態３に係る系統連系インバータ装置のコンバータ制御部によるダイオード短絡故障判定時の動作に係わるフローチャートThe flowchart regarding the operation | movement at the time of the diode short circuit failure determination by the converter control part of the grid connection inverter apparatus which concerns on Embodiment 3 of this invention.
　以下に、本発明の実施の形態に係る系統連系インバータ装置を図面に基づいて詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。 Hereinafter, a grid-connected inverter device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.
実施の形態１．
　図１は本発明の実施の形態１に係る系統連系インバータ装置を含む太陽光発電システムを示す図である。太陽光発電システム１００は、複数の直流電源である太陽電池ストリング１ａ，１ｂ，１ｃ，１ｄと、複数の太陽電池ストリング１ａ，１ｂ，１ｃ，１ｄが接続される系統連系インバータ装置３とを備える。以下では、複数の太陽電池ストリング１ａ，１ｂ，１ｃ，１ｄを「複数の太陽電池ストリング１」と省略する場合がある。複数の太陽電池ストリング１のそれぞれは、不図示の複数の太陽電池モジュールが直列に接続された構成であり、日射量に応じた直流電力を発生する。 Embodiment 1 FIG.
FIG. 1 is a diagram showing a photovoltaic power generation system including a grid-connected inverter device according to Embodiment 1 of the present invention. The solar power generation system 100 includes solar cell strings 1a, 1b, 1c, and 1d that are a plurality of DC power sources, and a grid-connected inverter device 3 to which the solar cell strings 1a, 1b, 1c, and 1d are connected. . Hereinafter, the plurality of solar cell strings 1a, 1b, 1c, and 1d may be abbreviated as “a plurality of solar cell strings 1”. Each of the plurality of solar cell strings 1 has a configuration in which a plurality of solar cell modules (not shown) are connected in series, and generates DC power corresponding to the amount of solar radiation.
　系統連系インバータ装置３はコンバータ制御部１６を備える。コンバータ制御部１６は、複数のコンバータ回路４ａ，４ｂ，４ｃ，４ｄのそれぞれを制御するためのゲートパルス指令Ｇｓを生成し、複数のゲートパルス発生器１７ａ，１７ｂ，１７ｃ，１７ｄのそれぞれに対して出力する。実施の形態に係る系統連系インバータ装置３は、コンバータ制御部１６によるゲートパルス指令Ｇｓの動作に特徴がある。以下では複数のコンバータ回路４ａ，４ｂ，４ｃ，４ｄを「複数のコンバータ回路４」と省略する場合がある。また複数のゲートパルス発生器１７ａ，１７ｂ，１７ｃ，１７ｄを「複数のゲートパルス発生器１７」と省略する場合がある。 The grid interconnection inverter device 3 includes a converter control unit 16. The converter control unit 16 generates a gate pulse command Gs for controlling each of the plurality of converter circuits 4a, 4b, 4c, 4d, and each of the plurality of gate pulse generators 17a, 17b, 17c, 17d. Output. The grid-connected inverter device 3 according to the embodiment is characterized in the operation of the gate pulse command Gs by the converter control unit 16. Hereinafter, the plurality of converter circuits 4a, 4b, 4c, 4d may be abbreviated as “a plurality of converter circuits 4”. The plurality of gate pulse generators 17a, 17b, 17c, and 17d may be abbreviated as “a plurality of gate pulse generators 17”.
　以下に、コンバータ制御部１６を中心として系統連系インバータ装置３を構成する機器の構成を具体的に説明する。 Hereinafter, the configuration of the devices constituting the grid interconnection inverter device 3 will be specifically described with the converter control unit 16 as the center.
　系統連系インバータ装置３は、複数の正極入力端子１０１ａ，１０１ｂ，１０１ｃ，１０１ｄと、複数の負極入力端子１０２ａ，１０２ｂ，１０２ｃ，１０２ｄと、系統出力端子１０３，１０４とを備える。 The grid interconnection inverter device 3 includes a plurality of positive input terminals 101a, 101b, 101c, 101d, a plurality of negative input terminals 102a, 102b, 102c, 102d, and system output terminals 103, 104.
　正極入力端子１０１ａには太陽電池ストリング１ａの正極出力端が接続され、負極入力端子１０２ａには太陽電池ストリング１ａの負極出力端が接続される。以下同様に、正極入力端子１０１ｂ，１０１ｃ，１０１ｄのそれぞれには、太陽電池ストリング１ｂ，１ｃ，１ｄの正極出力端が接続される。負極入力端子１０２ｂ，１０２ｃ，１０２ｄのそれぞれには、太陽電池ストリング１ｂ，１ｃ，１ｄの負極出力端が接続される。 The positive electrode output terminal of the solar cell string 1a is connected to the positive electrode input terminal 101a, and the negative electrode output terminal of the solar cell string 1a is connected to the negative electrode input terminal 102a. Similarly, the positive electrode output terminals of the solar cell strings 1b, 1c, and 1d are connected to the positive electrode input terminals 101b, 101c, and 101d, respectively. The negative electrode output terminals of the solar cell strings 1b, 1c, and 1d are connected to the negative electrode input terminals 102b, 102c, and 102d, respectively.
　系統出力端子１０３，１０４には、商用電力系統２に繋がる２つの系統接続線が接続される。 Two system connection lines connected to the commercial power system 2 are connected to the system output terminals 103 and 104.
　また系統連系インバータ装置３は、複数の平滑用コンデンサ７ａ，７ｂ，７ｃ，７ｄと、複数のコンバータ回路４と、平滑用コンデンサ８と、インバータ回路５と、出力リレー６とを備える。 The grid interconnection inverter device 3 includes a plurality of smoothing capacitors 7a, 7b, 7c, and 7d, a plurality of converter circuits 4, a smoothing capacitor 8, an inverter circuit 5, and an output relay 6.
　平滑用コンデンサ７ａは、太陽電池ストリング１ａから出力されてコンバータ回路４ａに入力される直流電圧を平滑する。平滑用コンデンサ７ａの一端は、正極側の直流母線Ｐを介して、正極入力端子１０１ａとコンバータ回路４ａの正極入力端とに接続される。平滑用コンデンサ７ａの他端は、負極側の直流母線Ｎを介して、負極入力端子１０２ａとコンバータ回路４ａの負極入力端とに接続される。 The smoothing capacitor 7a smoothes the DC voltage output from the solar cell string 1a and input to the converter circuit 4a. One end of the smoothing capacitor 7a is connected to the positive electrode input terminal 101a and the positive electrode input terminal of the converter circuit 4a via the positive-polarity DC bus P. The other end of the smoothing capacitor 7a is connected to the negative input terminal 102a and the negative input end of the converter circuit 4a via a negative DC bus N.
　コンバータ回路４ａは、リアクトル９ａ、スイッチング素子１０ａおよびダイオード１１ａを有する。 The converter circuit 4a includes a reactor 9a, a switching element 10a, and a diode 11a.
　リアクトル９ａの一端は、コンバータ回路４ａの正極入力端である。リアクトル９ａの一端は、正極入力端子１０１ａと平滑用コンデンサ７ａの一端とに接続される。リアクトル９ａの他端は、ダイオード１１ａのアノードと、スイッチング素子１０ａのコレクタとに接続される。 One end of the reactor 9a is a positive input terminal of the converter circuit 4a. One end of the reactor 9a is connected to the positive electrode input terminal 101a and one end of the smoothing capacitor 7a. The other end of the reactor 9a is connected to the anode of the diode 11a and the collector of the switching element 10a.
　ダイオード１１ａのカソードは、コンバータ回路４ａの正極出力端である。ダイオード１１ａのカソードは、平滑用コンデンサ８の一端とインバータ回路５の正極入力端とに接続される。 The cathode of the diode 11a is the positive output terminal of the converter circuit 4a. The cathode of the diode 11 a is connected to one end of the smoothing capacitor 8 and the positive input terminal of the inverter circuit 5.
　スイッチング素子１０ａのエミッタは、平滑用コンデンサ７ａの他端と平滑用コンデンサ８の他端とに接続される。スイッチング素子１０ａのゲートには、ゲートパルス発生器１７ａから出力されるゲートパルス信号１７ａ１が入力される。ゲートパルス信号１７ａ１は、太陽電池ストリング１ａから出力された電圧を、インバータ回路５が交流電圧を生成するために必要な電圧に昇圧する信号、またはダイオード１１ａが短絡故障検出時にスイッチング素子１０ａを短絡する信号である。 The emitter of the switching element 10a is connected to the other end of the smoothing capacitor 7a and the other end of the smoothing capacitor 8. The gate pulse signal 17a1 output from the gate pulse generator 17a is input to the gate of the switching element 10a. The gate pulse signal 17a1 is a signal for boosting the voltage output from the solar cell string 1a to a voltage necessary for the inverter circuit 5 to generate an AC voltage, or the diode 11a shorts the switching element 10a when a short circuit failure is detected. Signal.
　ゲートパルス発生器１７ａは、コンバータ制御部から入力されるゲートパルス指令Ｇｓに基づき、ゲートパルス信号１７ａ１をスイッチング素子１０ａに出力する。 The gate pulse generator 17a outputs a gate pulse signal 17a1 to the switching element 10a based on the gate pulse command Gs input from the converter control unit.
　平滑用コンデンサ７ｂは、太陽電池ストリング１ｂから出力されてコンバータ回路４ｂに入力される直流電圧を平滑する。平滑用コンデンサ７ｂの一端は、正極側の直流母線Ｐを介して、正極入力端子１０１ｂとコンバータ回路４ｂの正極入力端とに接続される。平滑用コンデンサ７ｂの他端は、負極側の直流母線Ｎを介して、負極入力端子１０２ｂとコンバータ回路４ｂの負極入力端とに接続される。 The smoothing capacitor 7b smoothes the DC voltage output from the solar cell string 1b and input to the converter circuit 4b. One end of the smoothing capacitor 7b is connected to the positive electrode input terminal 101b and the positive electrode input terminal of the converter circuit 4b via the positive DC bus P. The other end of the smoothing capacitor 7b is connected to the negative input terminal 102b and the negative input end of the converter circuit 4b via a negative DC bus N.
　コンバータ回路４ｂは、リアクトル９ｂ、スイッチング素子１０ｂおよびダイオード１１ｂを有する。 The converter circuit 4b includes a reactor 9b, a switching element 10b, and a diode 11b.
　リアクトル９ｂの一端は、コンバータ回路４ｂの正極入力端である。リアクトル９ｂの一端は、正極入力端子１０１ｂと平滑用コンデンサ７ｂの一端とに接続される。リアクトル９ｂの他端は、ダイオード１１ｂのアノードと、スイッチング素子１０ｂのコレクタとに接続される。 One end of the reactor 9b is a positive input terminal of the converter circuit 4b. One end of the reactor 9b is connected to the positive electrode input terminal 101b and one end of the smoothing capacitor 7b. The other end of the reactor 9b is connected to the anode of the diode 11b and the collector of the switching element 10b.
　ダイオード１１ｂのカソードは、コンバータ回路４ｂの正極出力端である。ダイオード１１ｂのカソードは、平滑用コンデンサ８の一端とインバータ回路５の正極入力端とに接続される。 The cathode of the diode 11b is the positive output terminal of the converter circuit 4b. The cathode of the diode 11 b is connected to one end of the smoothing capacitor 8 and the positive input terminal of the inverter circuit 5.
　スイッチング素子１０ｂのエミッタは、平滑用コンデンサ７ｂの他端と平滑用コンデンサ８の他端とに接続される。スイッチング素子１０ｂのゲートには、ゲートパルス発生器１７ｂから出力されるゲートパルス信号１７ｂ１が入力される。ゲートパルス信号１７ｂ１は、太陽電池ストリング１ｂから出力された電圧を、インバータ回路５が交流電圧を生成するために必要な電圧に昇圧し、ダイオード１１ｂが短絡故障検出時にスイッチング素子１０ｂを短絡する信号である。 The emitter of the switching element 10b is connected to the other end of the smoothing capacitor 7b and the other end of the smoothing capacitor 8. The gate pulse signal 17b1 output from the gate pulse generator 17b is input to the gate of the switching element 10b. The gate pulse signal 17b1 is a signal for boosting the voltage output from the solar cell string 1b to a voltage necessary for the inverter circuit 5 to generate an AC voltage, and the diode 11b short-circuits the switching element 10b when a short circuit failure is detected. is there.
　ゲートパルス発生器１７ｂは、コンバータ制御部から入力されるゲートパルス指令Ｇｓに基づき、ゲートパルス信号１７ｂ１をスイッチング素子１０ｂに出力する。 The gate pulse generator 17b outputs a gate pulse signal 17b1 to the switching element 10b based on the gate pulse command Gs input from the converter control unit.
　平滑用コンデンサ７ｃは、太陽電池ストリング１ｃから出力されてコンバータ回路４ｃに入力される直流電圧を平滑する。平滑用コンデンサ７ｃの一端は、正極側の直流母線Ｐを介して、正極入力端子１０１ｃとコンバータ回路４ｃの正極入力端とに接続される。平滑用コンデンサ７ｃの他端は、負極側の直流母線Ｎを介して、負極入力端子１０２ｃとコンバータ回路４ｃの負極入力端とに接続される。 The smoothing capacitor 7c smoothes the DC voltage output from the solar cell string 1c and input to the converter circuit 4c. One end of the smoothing capacitor 7c is connected to the positive input terminal 101c and the positive input end of the converter circuit 4c via the positive DC bus P. The other end of the smoothing capacitor 7c is connected to the negative input terminal 102c and the negative input end of the converter circuit 4c through a negative DC bus N.
　コンバータ回路４ｃは、リアクトル９ｃ、スイッチング素子１０ｃおよびダイオード１１ｃを有する。 The converter circuit 4c includes a reactor 9c, a switching element 10c, and a diode 11c.
　リアクトル９ｃの一端は、コンバータ回路４ｃの正極入力端である。リアクトル９ｃの一端は、正極入力端子１０１ｃと平滑用コンデンサ７ｃの一端とに接続される。リアクトル９ｃの他端は、ダイオード１１ｃのアノードと、スイッチング素子１０ｃのコレクタとに接続される。 One end of the reactor 9c is a positive input terminal of the converter circuit 4c. One end of the reactor 9c is connected to the positive electrode input terminal 101c and one end of the smoothing capacitor 7c. The other end of the reactor 9c is connected to the anode of the diode 11c and the collector of the switching element 10c.
　ダイオード１１ｃのカソードは、コンバータ回路４ｃの正極出力端である。ダイオード１１ｃのカソードは、平滑用コンデンサ８の一端とインバータ回路５の正極入力端とに接続される。 The cathode of the diode 11c is a positive output terminal of the converter circuit 4c. The cathode of the diode 11 c is connected to one end of the smoothing capacitor 8 and the positive input terminal of the inverter circuit 5.
　スイッチング素子１０ｃのエミッタは、平滑用コンデンサ７ｃの他端と平滑用コンデンサ８の他端とに接続される。スイッチング素子１０ｃのゲートには、ゲートパルス発生器１７ｃから出力されるゲートパルス信号１７ｃ１が入力される。ゲートパルス信号１７ｃ１は、太陽電池ストリング１ｃから出力された電圧を、インバータ回路５が交流電圧を生成するために必要な電圧に昇圧し、ダイオード１１ｃが短絡故障検出時にスイッチング素子１０ｃを短絡する信号である。 The emitter of the switching element 10c is connected to the other end of the smoothing capacitor 7c and the other end of the smoothing capacitor 8. The gate pulse signal 17c1 output from the gate pulse generator 17c is input to the gate of the switching element 10c. The gate pulse signal 17c1 is a signal that boosts the voltage output from the solar cell string 1c to a voltage necessary for the inverter circuit 5 to generate an AC voltage, and the diode 11c shorts the switching element 10c when a short circuit failure is detected. is there.
　ゲートパルス発生器１７ｃは、コンバータ制御部から入力されるゲートパルス指令Ｇｓに基づき、ゲートパルス信号１７ｃ１をスイッチング素子１０ｃに出力する。 The gate pulse generator 17c outputs a gate pulse signal 17c1 to the switching element 10c based on the gate pulse command Gs input from the converter control unit.
　平滑用コンデンサ７ｄは、太陽電池ストリング１ｄから出力されてコンバータ回路４ｄに入力される直流電圧を平滑する。平滑用コンデンサ７ｄの一端は、正極側の直流母線Ｐを介して、正極入力端子１０１ｄとコンバータ回路４ｄの正極入力端とに接続される。平滑用コンデンサ７ｄの他端は、負極側の直流母線Ｎを介して、負極入力端子１０２ｄとコンバータ回路４ｄの負極入力端とに接続される。 The smoothing capacitor 7d smoothes the DC voltage output from the solar cell string 1d and input to the converter circuit 4d. One end of the smoothing capacitor 7d is connected to the positive input terminal 101d and the positive input terminal of the converter circuit 4d via the positive DC bus P. The other end of the smoothing capacitor 7d is connected to the negative input terminal 102d and the negative input end of the converter circuit 4d via a negative DC bus N.
　コンバータ回路４ｄは、リアクトル９ｄ、スイッチング素子１０ｄおよびダイオード１１ｄを有する。 The converter circuit 4d includes a reactor 9d, a switching element 10d, and a diode 11d.
　リアクトル９ｄの一端は、コンバータ回路４ｄの正極入力端である。リアクトル９ｄの一端は、正極入力端子１０１ｄと平滑用コンデンサ７ｄの一端とに接続される。リアクトル９ｄの他端は、ダイオード１１ｄのアノードと、スイッチング素子１０ｄのコレクタとに接続される。 One end of the reactor 9d is a positive input terminal of the converter circuit 4d. One end of the reactor 9d is connected to the positive electrode input terminal 101d and one end of the smoothing capacitor 7d. The other end of the reactor 9d is connected to the anode of the diode 11d and the collector of the switching element 10d.
　ダイオード１１ｄのカソードは、コンバータ回路４ｄの正極出力端である。ダイオード１１ｄのカソードは、平滑用コンデンサ８の一端とインバータ回路５の正極入力端とに接続される。 The cathode of the diode 11d is the positive output terminal of the converter circuit 4d. The cathode of the diode 11 d is connected to one end of the smoothing capacitor 8 and the positive input terminal of the inverter circuit 5.
　スイッチング素子１０ｄのエミッタは、平滑用コンデンサ７ｄの他端と平滑用コンデンサ８の他端とに接続される。スイッチング素子１０ｄのゲートには、ゲートパルス発生器１７ｄから出力されるゲートパルス信号１７ｄ１が入力される。ゲートパルス信号１７ｄ１は、太陽電池ストリング１ｄから出力された電圧を、インバータ回路５が交流電圧を生成するために必要な電圧に昇圧し、ダイオード１１ｄが短絡故障検出時にスイッチング素子１０ｄを短絡する信号である。 The emitter of the switching element 10d is connected to the other end of the smoothing capacitor 7d and the other end of the smoothing capacitor 8. The gate pulse signal 17d1 output from the gate pulse generator 17d is input to the gate of the switching element 10d. The gate pulse signal 17d1 is a signal for boosting the voltage output from the solar cell string 1d to a voltage necessary for the inverter circuit 5 to generate an AC voltage, and the diode 11d short-circuits the switching element 10d when a short-circuit fault is detected. is there.
　ゲートパルス発生器１７ｄは、コンバータ制御部から入力されるゲートパルス指令Ｇｓに基づき、ゲートパルス信号１７ｄ１をスイッチング素子１０ｄに出力する。 The gate pulse generator 17d outputs a gate pulse signal 17d1 to the switching element 10d based on the gate pulse command Gs input from the converter control unit.
　平滑用コンデンサ８の一端は、複数のダイオード１１ａ，１１ｂ，１１ｃ，１１ｄのそれぞれのカソードと、インバータ回路５の正極入力端とに接続される。平滑用コンデンサ８の他端は、複数のダイオード１１ａ，１１ｂ，１１ｃ，１１ｄのそれぞれのアノードと、インバータ回路５の負極入力端とに接続される。平滑用コンデンサ８は、複数のコンバータ回路４のそれぞれから出力されてインバータ回路５に入力される直流電圧を平滑する。 One end of the smoothing capacitor 8 is connected to the cathodes of the plurality of diodes 11 a, 11 b, 11 c, and 11 d and the positive input terminal of the inverter circuit 5. The other end of the smoothing capacitor 8 is connected to the anodes of the plurality of diodes 11 a, 11 b, 11 c, 11 d and the negative input terminal of the inverter circuit 5. The smoothing capacitor 8 smoothes the DC voltage output from each of the plurality of converter circuits 4 and input to the inverter circuit 5.
　インバータ回路５は平滑用コンデンサ８の充電電圧を交流電圧に変換する動作する。インバータ回路５の交流出力端は、出力リレー６を介して系統出力端子１０３，１０４に接続される。 The inverter circuit 5 operates to convert the charging voltage of the smoothing capacitor 8 into an AC voltage. The AC output terminal of the inverter circuit 5 is connected to the system output terminals 103 and 104 via the output relay 6.
　出力リレー６は、インバータ回路５と、２つの系統出力端子１０３，１０４との間に配置される。出力リレー６はインバータ回路５と商用電力系統２との接続路を開閉する機能である。 The output relay 6 is disposed between the inverter circuit 5 and the two system output terminals 103 and 104. The output relay 6 has a function of opening and closing a connection path between the inverter circuit 5 and the commercial power system 2.
　また系統連系インバータ装置３は、複数の電流検出器１２ａ，１２ｂ，１２ｃ，１２ｄと、複数の電圧検出器１３ａ，１３ｂ，１３ｃ，１３ｄとを備える。複数の電流検出器１２ａ，１２ｂ，１２ｃ，１２ｄと、複数の電圧検出器１３ａ，１３ｂ，１３ｃ，１３ｄと、コンバータ制御部１６とは、系統連系インバータ装置３の制御部２００を構成する。 The grid interconnection inverter device 3 includes a plurality of current detectors 12a, 12b, 12c, and 12d and a plurality of voltage detectors 13a, 13b, 13c, and 13d. The plurality of current detectors 12 a, 12 b, 12 c, 12 d, the plurality of voltage detectors 13 a, 13 b, 13 c, 13 d, and the converter control unit 16 constitute a control unit 200 of the grid interconnection inverter device 3.
　制御部２００は、複数のコンバータ回路４を駆動させるために用いられる。具体的には、制御部２００は、複数の太陽電池ストリング１の動作点を最大電力点に追従させる最大電力追尾制御であるＭＰＰＴ（Ｍａｘｉｍｕｍ　Ｐｏｗｅｒ　Ｐｏｉｎｔ　Ｔｒａｃｋｉｎｇ）制御により決定されたゲートパルス指令を生成する。または制御部２００は、複数のコンバータ回路４のそれぞれを構成するダイオード１１ａ，１１ｂ，１１ｃ，１１ｄの短絡故障を検出したとき、複数のコンバータ回路４のそれぞれを構成するスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄを短絡するゲートパルス信号１７ａ１，１７ｂ１，１７ｃ１，１７ｄ１を生成する。 The control unit 200 is used to drive a plurality of converter circuits 4. Specifically, the control unit 200 generates a gate pulse command determined by MPPT (Maximum Power Point Tracking) control, which is maximum power tracking control that causes the operating points of the plurality of solar cell strings 1 to follow the maximum power point. . Alternatively, when the control unit 200 detects a short-circuit failure of the diodes 11a, 11b, 11c, and 11d that configure each of the plurality of converter circuits 4, the switching elements 10a, 10b, and 10c that configure each of the plurality of converter circuits 4 Gate pulse signals 17a1, 17b1, 17c1, and 17d1 that short-circuit 10d are generated.
　なお図１に示すスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄは、ＩＧＢＴ（Ｉｎｓｕｌａｔｅｄ　Ｇａｔｅ　Ｂｉｐｏｌａｒ　Ｔｒａｎｓｉｓｔｏｒ）であるが、ＩＧＢＴ以外のトランジスタでもよい。一例としてはＭＯＳＦＥＴ（Ｍｅｔａｌ－Ｏｘｉｄｅ－Ｓｅｍｉｃｏｎｄｕｃｔｏｒ　Ｆｉｅｌｄ－Ｅｆｆｅｃｔ　Ｔｒａｎｓｉｓｔｏｒ）である。 Note that the switching elements 10a, 10b, 10c, and 10d shown in FIG. 1 are IGBTs (Insulated Gate Bipolar Transistors), but transistors other than IGBTs may be used. An example is a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor).
　また系統連系インバータ装置３では４つのコンバータ回路４ａ，４ｂ，４ｃ，４ｄが用いられているが、コンバータ回路数は２つ以上であればよい。また実施の形態１ではコンバータ回路４ａ，４ｂ，４ｃ，４ｄの一例を示すが、コンバータ回路の構成は図示例に限定されず、スイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄおよびダイオード１１ａ，１１ｂ，１１ｃ，１１ｄを用いて、直流電圧を所望の直流電圧値に変換する電力変換回路であれば他の電力変換回路でもよい。 In the grid-connected inverter device 3, four converter circuits 4a, 4b, 4c, and 4d are used, but the number of converter circuits may be two or more. In the first embodiment, an example of the converter circuits 4a, 4b, 4c, and 4d is shown, but the configuration of the converter circuit is not limited to the illustrated example, and the switching elements 10a, 10b, 10c, and 10d and the diodes 11a, 11b, 11c, Other power conversion circuits may be used as long as the power conversion circuit converts the DC voltage into a desired DC voltage value using 11d.
　また図１では４つの太陽電池ストリング１ａ，１ｂ，１ｃ，１ｄが系統連系インバータ装置３に接続されているが、太陽電池ストリングの接続数は図示例に限定されるものではなく、２つ以上あればよい。この場合、太陽光発電システム１００には、太陽電池ストリングの数に対応する数のコンバータ回路４が用いられる。 In FIG. 1, four solar cell strings 1a, 1b, 1c, and 1d are connected to the grid interconnection inverter device 3. However, the number of solar cell strings connected is not limited to the illustrated example, and two or more solar cell strings are connected. I just need it. In this case, the photovoltaic power generation system 100 uses a number of converter circuits 4 corresponding to the number of solar cell strings.
　以下、制御部２００の構成を具体的に説明する。 Hereinafter, the configuration of the control unit 200 will be specifically described.
　負極入力端子１０２ａとコンバータ回路４ａとの間の負極側の直流母線Ｎには、電流検出素子３０ａが配置される。電流検出素子３０ａは、当該位置における電流値を検出する。電流検出素子３０ａには、カレントトランスまたはシャント抵抗が用いられる。 A current detection element 30a is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102a and the converter circuit 4a. The current detection element 30a detects a current value at the position. A current transformer or a shunt resistor is used for the current detection element 30a.
　電流検出器１２ａは、増幅器またはレベルシフト回路で実現され、電流検出素子３０ａで検出された電流に正比例した電圧を、電力演算器１４ａが取り扱い可能な低圧範囲内の電流検出電圧に変換して出力する。この電流検出電圧は、太陽電池ストリング１ａの出力電流の電流値Ｉｓａに相当する。電流検出器１２ａから出力された電流値Ｉｓａは、コンバータ制御部１６に入力される。 The current detector 12a is realized by an amplifier or a level shift circuit, and converts a voltage directly proportional to the current detected by the current detection element 30a into a current detection voltage within a low voltage range that can be handled by the power calculator 14a and outputs the voltage. To do. This current detection voltage corresponds to the current value Isa of the output current of the solar cell string 1a. The current value Isa output from the current detector 12 a is input to the converter control unit 16.
　電圧検出器１３ａの一端は、正極側の直流母線Ｐにおいて、正極入力端子１０１ａとリアクトル９ａの一端と平滑用コンデンサ７ａの一端とに接続される。電圧検出器１３ａの他端は、負極側の直流母線Ｎにおいて、負極入力端子１０２ａと平滑用コンデンサ７ａの他端とに接続される。 One end of the voltage detector 13a is connected to the positive electrode input terminal 101a, one end of the reactor 9a, and one end of the smoothing capacitor 7a in the DC bus P on the positive electrode side. The other end of the voltage detector 13a is connected to the negative input terminal 102a and the other end of the smoothing capacitor 7a on the negative DC bus N.
　電圧検出器１３ａは、太陽電池ストリング１ａの出力電圧値である電圧値Ｖｓａを検出する。電圧検出器１３ａから出力された電圧値Ｖｓａは、コンバータ制御部１６に入力される。 The voltage detector 13a detects the voltage value Vsa which is the output voltage value of the solar cell string 1a. The voltage value Vsa output from the voltage detector 13a is input to the converter control unit 16.
　負極入力端子１０２ｂとコンバータ回路４ｂとの間の負極側の直流母線Ｎには、電流検出素子３０ｂが配置される。電流検出素子３０ｂは、当該位置における電流値を検出する。電流検出素子３０ｂには、カレントトランスまたはシャント抵抗が用いられる。 A current detection element 30b is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102b and the converter circuit 4b. The current detection element 30b detects a current value at the position. A current transformer or a shunt resistor is used for the current detection element 30b.
　電流検出器１２ｂは、増幅器またはレベルシフト回路で実現され、電流検出素子３０ｂで検出された電流に正比例した電圧を、電力演算器１４ｂが取り扱い可能な低圧範囲内の電流検出電圧に変換して出力する。この電流検出電圧は、太陽電池ストリング１ｂの出力電流の電流値Ｉｓｂに相当する。電流検出器１２ｂから出力された電流値Ｉｓｂは、コンバータ制御部１６に入力される。 The current detector 12b is realized by an amplifier or a level shift circuit, and converts a voltage directly proportional to the current detected by the current detection element 30b into a current detection voltage within a low voltage range that can be handled by the power calculator 14b and outputs the voltage. To do. This current detection voltage corresponds to the current value Isb of the output current of the solar cell string 1b. The current value Isb output from the current detector 12 b is input to the converter control unit 16.
　電圧検出器１３ｂの一端は、正極側の直流母線Ｐにおいて、正極入力端子１０１ｂとリアクトル９ｂの一端と平滑用コンデンサ７ｂの一端とに接続される。電圧検出器１３ｂの他端は、負極側の直流母線Ｎにおいて、負極入力端子１０２ｂと平滑用コンデンサ７ｂの他端とに接続される。電圧検出器１３ｂは、太陽電池ストリング１ｂの出力電圧値である電圧値Ｖｓｂを検出する。電圧検出器１３ｂから出力された電圧値Ｖｓｂは、コンバータ制御部１６に入力される。 One end of the voltage detector 13b is connected to the positive electrode input terminal 101b, one end of the reactor 9b, and one end of the smoothing capacitor 7b in the DC bus P on the positive electrode side. The other end of the voltage detector 13b is connected to the negative input terminal 102b and the other end of the smoothing capacitor 7b on the negative DC bus N. The voltage detector 13b detects a voltage value Vsb that is an output voltage value of the solar cell string 1b. The voltage value Vsb output from the voltage detector 13b is input to the converter control unit 16.
　負極入力端子１０２ｃとコンバータ回路４ｃとの間の負極側の直流母線Ｎには、電流検出素子３０ｃが配置される。電流検出素子３０ｃは、当該位置における電流値を検出する。電流検出素子３０ｃには、カレントトランスまたはシャント抵抗が用いられる。 A current detection element 30c is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102c and the converter circuit 4c. The current detection element 30c detects a current value at the position. A current transformer or a shunt resistor is used for the current detection element 30c.
　電流検出器１２ｃは、増幅器またはレベルシフト回路で実現され、電流検出素子３０ｃで検出された電流に正比例した電圧を、電力演算器１４ｃが取り扱い可能な低圧範囲内の電流検出電圧に変換して出力する。この電流検出電圧は、太陽電池ストリング１ｃの出力電流の電流値Ｉｓｃに相当する。電流検出器１２ｃから出力された電流値Ｉｓｃは、コンバータ制御部１６に入力される。 The current detector 12c is realized by an amplifier or a level shift circuit, and converts a voltage directly proportional to the current detected by the current detection element 30c into a current detection voltage within a low voltage range that can be handled by the power calculator 14c and outputs the voltage. To do. This current detection voltage corresponds to the current value Isc of the output current of the solar cell string 1c. The current value Isc output from the current detector 12 c is input to the converter control unit 16.
　電圧検出器１３ｃの一端は、正極側の直流母線Ｐにおいて、正極入力端子１０１ｃとリアクトル９ｃの一端と平滑用コンデンサ７ｃの一端とに接続される。電圧検出器１３ｃの他端は、負極側の直流母線Ｎにおいて、負極入力端子１０２ｃと平滑用コンデンサ７ｃの他端とに接続される。電圧検出器１３ｃは、太陽電池ストリング１ｃの出力電圧値である電圧値Ｖｓｃを検出する。電圧検出器１３ｃから出力された電圧値Ｖｓｃは、コンバータ制御部１６に入力される。 One end of the voltage detector 13c is connected to the positive electrode input terminal 101c, one end of the reactor 9c, and one end of the smoothing capacitor 7c in the DC bus P on the positive electrode side. The other end of the voltage detector 13c is connected to the negative input terminal 102c and the other end of the smoothing capacitor 7c in the negative DC bus N. The voltage detector 13c detects a voltage value Vsc that is an output voltage value of the solar cell string 1c. The voltage value Vsc output from the voltage detector 13 c is input to the converter control unit 16.
　負極入力端子１０２ｄとコンバータ回路４ｄとの間の負極側の直流母線Ｎには、電流検出素子３０ｄが配置される。電流検出素子３０ｄは、当該位置における電流値を検出する。電流検出素子３０ｄには、カレントトランスまたはシャント抵抗が用いられる。 A current detection element 30d is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102d and the converter circuit 4d. The current detection element 30d detects a current value at the position. A current transformer or a shunt resistor is used for the current detection element 30d.
　電流検出器１２ｄは、増幅器またはレベルシフト回路で実現され、電流検出素子３０ｄで検出された電流に正比例した電圧を、電力演算器１４ｄが取り扱い可能な低圧範囲内の電流検出電圧に変換して出力する。この電流検出電圧は、太陽電池ストリング１ｄの出力電流の電流値Ｉｓｄに相当する。電流検出器１２ｄから出力された電流値Ｉｓｄは、コンバータ制御部１６に入力される。 The current detector 12d is realized by an amplifier or a level shift circuit, and converts a voltage directly proportional to the current detected by the current detection element 30d into a current detection voltage within a low voltage range that can be handled by the power calculator 14d and outputs the voltage. To do. This current detection voltage corresponds to the current value Isd of the output current of the solar cell string 1d. The current value Isd output from the current detector 12 d is input to the converter control unit 16.
　電圧検出器１３ｄの一端は、正極側の直流母線Ｐにおいて、正極入力端子１０１ｄとリアクトル９ｄの一端と平滑用コンデンサ７ｄの一端とに接続される。電圧検出器１３ｄの他端は、負極側の直流母線Ｎにおいて、負極入力端子１０２ｄと平滑用コンデンサ７ｄの他端とに接続される。電圧検出器１３ｄは、太陽電池ストリング１ｄの出力電圧値である電圧値Ｖｓｄを検出する。電圧検出器１３ｄから出力された電圧値Ｖｓｄは、コンバータ制御部１６に入力される。 One end of the voltage detector 13d is connected to the positive electrode input terminal 101d, one end of the reactor 9d, and one end of the smoothing capacitor 7d on the DC bus P on the positive electrode side. The other end of the voltage detector 13d is connected to the negative input terminal 102d and the other end of the smoothing capacitor 7d on the negative DC bus N. The voltage detector 13d detects a voltage value Vsd that is an output voltage value of the solar cell string 1d. The voltage value Vsd output from the voltage detector 13d is input to the converter control unit 16.
　コンバータ制御部１６は、複数の電流値Ｉｓａ，Ｉｓｂ，Ｉｓｃ，Ｉｓｄと、複数の電圧値Ｖｓａ，Ｖｓｂ，Ｖｓｃ，Ｖｓｄとに基づき、複数のコンバータ回路４を動作させるためのゲートパルス指令Ｇｓを生成して、複数のゲートパルス発生器１７に出力する。 The converter control unit 16 generates a gate pulse command Gs for operating the plurality of converter circuits 4 based on the plurality of current values Isa, Isb, Isc, Isd and the plurality of voltage values Vsa, Vsb, Vsc, Vsd. Then, it outputs to a plurality of gate pulse generators 17.
　具体的には、コンバータ制御部１６は、複数のコンバータ回路４のそれぞれを構成するダイオード１１ａ，１１ｂ，１１ｃ，１１ｄの何れかが短絡故障しているか否か、すなわちダイオード１１ａ，１１ｂ，１１ｃ，１１ｄの何れかの短絡故障の有無を判定する。またコンバータ制御部１６は、複数のコンバータ回路４を複数の太陽電池ストリング１の最大電力点で動作させる第１のゲートパルス指令２１ａを生成する。そしてコンバータ制御部１６は、第１のゲートパルス指令２１ａと、短絡故障発生時に複数のコンバータ回路４の全てのスイッチング素子を短絡する第２のゲートパルス指令２２ａとの何れかを選択し、選択した第１のゲートパルス指令２１ａまたは第２のゲートパルス指令２２ａをゲートパルス指令Ｇｓとして、複数のゲートパルス発生器１７へ出力する。 Specifically, the converter control unit 16 determines whether or not any of the diodes 11a, 11b, 11c, and 11d constituting each of the plurality of converter circuits 4 is short-circuited, that is, the diodes 11a, 11b, 11c, and 11d. The presence or absence of any short-circuit failure is determined. Moreover, the converter control part 16 produces | generates the 1st gate pulse command 21a which operates the some converter circuit 4 at the maximum electric power point of the some solar cell string 1. FIG. Then, the converter control unit 16 selects and selects either the first gate pulse command 21a or the second gate pulse command 22a that short-circuits all the switching elements of the plurality of converter circuits 4 when a short circuit failure occurs. The first gate pulse command 21a or the second gate pulse command 22a is output to the plurality of gate pulse generators 17 as the gate pulse command Gs.
　次にコンバータ制御部１６の構成を詳細に説明する。 Next, the configuration of the converter control unit 16 will be described in detail.
　図２は図１に示すコンバータ制御部１６の構成図である。図２に示すコンバータ制御部１６は短絡故障検出部２０、ＭＰＰＴ制御部２１およびゲートパルス指令生成部２２を備える。 FIG. 2 is a block diagram of the converter control unit 16 shown in FIG. The converter control unit 16 shown in FIG. 2 includes a short-circuit fault detection unit 20, an MPPT control unit 21, and a gate pulse command generation unit 22.
　短絡故障検出部２０は複数の電流検出器１２ａ，１２ｂ，１２ｃ，１２ｄで検出された電流値Ｉｓａ，Ｉｓｂ，Ｉｓｃ，Ｉｓｄを入力し、電流値Ｉｓａ，Ｉｓｂ，Ｉｓｃ，Ｉｓｄに基づき複数のコンバータ回路４のそれぞれを構成するダイオード１１ａ，１１ｂ，１１ｃ，１１ｄの何れかの短絡故障の有無を判定する。 The short-circuit fault detection unit 20 inputs the current values Isa, Isb, Isc, Isd detected by the plurality of current detectors 12a, 12b, 12c, 12d, and a plurality of converter circuits based on the current values Isa, Isb, Isc, Isd. 4 is determined whether or not there is a short circuit fault in any of the diodes 11a, 11b, 11c, and 11d constituting each of the four.
　複数のコンバータ回路４のそれぞれを構成するダイオード１１ａ，１１ｂ，１１ｃ，１１ｄが短絡故障せずに正常な場合、電流値Ｉｓａ，Ｉｓｂ，Ｉｓｃ，Ｉｓｄ≧０となる。一方、複数のコンバータ回路４のそれぞれを構成するダイオード１１ａ，１１ｂ，１１ｃ，１１ｄの何れかが短絡故障した場合、その電流値は０よりも小さい値となる。ダイオード１１ｄが短絡故障したとき、コンバータ回路４ｄに接続される太陽電池ストリング１ｄに逆電流が流れるため、電流検出器１２ｄで検出される電流値はＩｓｄ＜０となる。 When the diodes 11a, 11b, 11c and 11d constituting each of the plurality of converter circuits 4 are normal without causing a short circuit failure, the current values Isa, Isb, Isc and Isd ≧ 0. On the other hand, when any one of the diodes 11a, 11b, 11c, and 11d constituting each of the plurality of converter circuits 4 is short-circuited, the current value is smaller than zero. When the diode 11d has a short circuit failure, a reverse current flows through the solar cell string 1d connected to the converter circuit 4d, so that the current value detected by the current detector 12d is Isd <0.
　すなわち短絡故障検出部２０は、下記（１）式に基づきダイオード１１ａ，１１ｂ，１１ｃ，１１ｄの何れにも短絡故障が生じていないことを判定し、下記（２）式に基づきダイオード１１ａ，１１ｂ，１１ｃ，１１ｄの何れかに短絡故障が生じていることを判定する。そして短絡故障検出部２０は、短絡故障の有無を示す判定結果２０ａをゲートパルス指令生成部２２へ出力する。 That is, the short-circuit fault detection unit 20 determines that no short-circuit fault has occurred in any of the diodes 11a, 11b, 11c, and 11d based on the following equation (1), and the diodes 11a, 11b, It is determined that a short circuit failure has occurred in either 11c or 11d. Then, the short-circuit fault detection unit 20 outputs a determination result 20 a indicating the presence or absence of a short-circuit fault to the gate pulse command generation unit 22.
　Ｉｓａ≧０、Ｉｓｂ≧０、Ｉｓｃ≧０およびＩｓｄ≧０・・・（１）
　Ｉｓａ＜０、Ｉｓｂ＜０、Ｉｓｃ＜０またはＩｓｄ＜０・・・（２） Isa ≧ 0, Isb ≧ 0, Isc ≧ 0 and Isd ≧ 0 (1)
Isa <0, Isb <0, Isc <0 or Isd <0 (2)
　上記の特許文献１では、入力される直流電圧がコンバータ回路の出力電圧と同じ値まで上昇したときに短絡故障を検出するように構成されている。ところが、太陽電池が直流電源として接続される場合、ダイオードが短絡故障していなくても、太陽電池の接続枚数によっては入力される直流電圧がコンバータ回路の出力電圧と同じ値になる場合がある。このため入力される直流電圧とコンバータ回路の出力電圧との比較ではダイオードの短絡故障を誤検出する可能性がある。 In the above-mentioned Patent Document 1, a short-circuit fault is detected when the input DC voltage rises to the same value as the output voltage of the converter circuit. However, when the solar cell is connected as a DC power source, the input DC voltage may be the same value as the output voltage of the converter circuit depending on the number of connected solar cells even if the diode is not short-circuited. For this reason, there is a possibility that a short circuit failure of the diode is erroneously detected by comparing the input DC voltage with the output voltage of the converter circuit.
　このような短絡故障の誤検出を防止するため、実施の形態１に係る系統連系インバータ装置３のコンバータ制御部１６は、太陽電池と系統連系インバータ装置３との間に流れる電流の向きにより短絡故障の有無を判定するように構成されている。 In order to prevent such erroneous detection of a short-circuit failure, the converter control unit 16 of the grid-connected inverter device 3 according to Embodiment 1 determines the direction of the current flowing between the solar cell and the grid-connected inverter device 3. It is comprised so that the presence or absence of a short circuit failure may be determined.
　ＭＰＰＴ制御部２１は、複数の電流検出器１２ａ，１２ｂ，１２ｃ，１２ｄで検出された電流値Ｉｓａ，Ｉｓｂ，Ｉｓｃ，Ｉｓｄと、複数の電圧検出器１３ａ，１３ｂ，１３ｃ，１３ｄで検出された電圧値Ｖｓａ，Ｖｓｂ，Ｖｓｃ，Ｖｓｄとを入力とし、ＭＰＰＴ制御により決定された第１のゲートパルス指令２１ａを生成して、ゲートパルス指令生成部２２へ出力する。 The MPPT control unit 21 includes current values Isa, Isb, Isc, Isd detected by the plurality of current detectors 12a, 12b, 12c, 12d, and voltages detected by the plurality of voltage detectors 13a, 13b, 13c, 13d. The values Vsa, Vsb, Vsc, and Vsd are input, the first gate pulse command 21a determined by the MPPT control is generated, and is output to the gate pulse command generation unit 22.
　太陽電池ストリングの最大電力点を検出するＭＰＰＴ制御は、一般的に良く知られている山登り法で実施される。なおＭＰＰＴ制御はさまざまな方法が提案されているため、山登り法以外の制御で実施されるものでもよい。太陽電池の出力特性は最大電力点をもつため、山登り法は太陽電池の電力の増加減により、最大点の方向を推測し、電圧、電流を少しずつ変化させることで最大点を検出する方法である。 The MPPT control for detecting the maximum power point of the solar cell string is performed by a generally well-known hill-climbing method. Since various methods have been proposed for MPPT control, control other than hill climbing may be performed. Since the output characteristics of solar cells have a maximum power point, the hill-climbing method is a method that estimates the direction of the maximum point by increasing or decreasing the power of the solar cell and detects the maximum point by gradually changing the voltage and current. is there.
　ゲートパルス指令生成部２２は、短絡故障検出部２０から出力された短絡故障の有無を示す判定結果２０ａと、ＭＰＰＴ制御部２１から出力された第１のゲートパルス指令２１ａとを入力し、判定結果２０ａに基づき短絡故障の有無を判定する。そしてゲートパルス指令生成部２２は、短絡故障の判定結果に応じて、前述した第１のゲートパルス指令２１ａをゲートパルス指令Ｇｓとしてゲートパルス発生器１７ａ，１７ｂ，１７ｃ，１７ｄへ出力し、またはゲートパルス指令生成部２２で生成される第２のゲートパルス指令２２ａを生成しゲートパルス指令Ｇｓとしてゲートパルス発生器１７ａ，１７ｂ，１７ｃ，１７ｄへ出力する。 The gate pulse command generation unit 22 receives the determination result 20a indicating the presence or absence of a short-circuit failure output from the short-circuit failure detection unit 20 and the first gate pulse command 21a output from the MPPT control unit 21, and the determination result The presence or absence of a short circuit failure is determined based on 20a. Then, the gate pulse command generation unit 22 outputs the first gate pulse command 21a described above as the gate pulse command Gs to the gate pulse generators 17a, 17b, 17c, and 17d according to the determination result of the short circuit failure, or the gate A second gate pulse command 22a generated by the pulse command generator 22 is generated and output to the gate pulse generators 17a, 17b, 17c, and 17d as the gate pulse command Gs.
　具体的には、判定結果２０ａにより短絡故障が生じていないと判定したゲートパルス指令生成部２２は、ＭＰＰＴ制御部２１から出力された第１のゲートパルス指令２１ａをゲートパルス指令Ｇｓとしてゲートパルス発生器１７ａ，１７ｂ，１７ｃ，１７ｄへ出力する。判定結果２０ａにより短絡故障が生じていると判定したゲートパルス指令生成部２２は、複数のコンバータ回路４の全てのスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄを短絡する第２のゲートパルス指令２２ａを生成し、第２のゲートパルス指令２２ａをゲートパルス指令Ｇｓとしてゲートパルス発生器１７ａ，１７ｂ，１７ｃ，１７ｄへ出力する。 Specifically, the gate pulse command generation unit 22 that has determined that a short circuit failure has not occurred based on the determination result 20a generates a gate pulse using the first gate pulse command 21a output from the MPPT control unit 21 as the gate pulse command Gs. To the devices 17a, 17b, 17c and 17d. The gate pulse command generator 22 that has determined that a short-circuit failure has occurred based on the determination result 20a generates a second gate pulse command 22a that short-circuits all the switching elements 10a, 10b, 10c, and 10d of the plurality of converter circuits 4. The second gate pulse command 22a is output to the gate pulse generators 17a, 17b, 17c and 17d as the gate pulse command Gs.
　コンバータ制御部１６の構成をさらに詳細に説明する。 The configuration of the converter control unit 16 will be described in more detail.
　ダイオードが短絡故障した場合、複数のコンバータ回路４のそれぞれを構成する全てのスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄの動作を停止したときでも太陽電池ストリングへの逆電流を停止することができない。そこでコンバータ制御部１６は、ダイオードが短絡故障したコンバータ回路に接続される太陽電池ストリングに逆電流を流さないために、複数のコンバータ回路４のそれぞれを構成する全てのスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄを短絡させることにより、複数の太陽電池ストリング１を全て短絡状態にさせる。これによりダイオードが短絡故障したコンバータ回路に接続される太陽電池ストリングに逆電流が流れることを防止できる。 When a short circuit failure occurs in the diode, the reverse current to the solar cell string cannot be stopped even when the operations of all the switching elements 10a, 10b, 10c, and 10d constituting each of the plurality of converter circuits 4 are stopped. Therefore, the converter control unit 16 prevents all the switching elements 10a, 10b, 10c, and the like constituting each of the plurality of converter circuits 4 from flowing a reverse current to the solar cell string connected to the converter circuit in which the diode is short-circuited. By short-circuiting 10d, the plurality of solar cell strings 1 are all short-circuited. Thereby, it can prevent that a reverse current flows into the solar cell string connected to the converter circuit in which the diode short-circuited.
　以上に説明したコンバータ制御部１６の動作を図３を用いて説明する。 The operation of the converter control unit 16 described above will be described with reference to FIG.
　図３は本発明の実施の形態１に係る系統連系インバータ装置のコンバータ制御部によるダイオード短絡故障判定時の動作に係わるフローチャートである。 FIG. 3 is a flowchart relating to the operation at the time of determining a diode short-circuit fault by the converter control unit of the grid-connected inverter device according to the first embodiment of the present invention.
　（Ｓ１）短絡故障検出部２０は、複数の電流検出器１２ａ，１２ｂ，１２ｃ，１２ｄにより検出された電流値Ｉｓａ，Ｉｓｂ，Ｉｓｃ，Ｉｓｄを入力する。 (S1) The short-circuit fault detection unit 20 inputs the current values Isa, Isb, Isc, Isd detected by the plurality of current detectors 12a, 12b, 12c, 12d.
　（Ｓ２）短絡故障検出部２０は下記（３）式によりコンバータ回路４ａのダイオード１１ａが短絡故障しているか否かを判定する。 (S2) The short-circuit fault detection unit 20 determines whether or not the diode 11a of the converter circuit 4a has a short-circuit fault by the following equation (3).
　Ｉｓａ≧０［Ａ］・・・（３） Isa ≧ 0 [A] (3)
　（Ｓ３）電流値Ｉｓａが上記（３）式の条件を満たす場合（Ｓ２，Ｙｅｓ）、短絡故障検出部２０はコンバータ回路４ａのダイオード１１ａが正常であると判定し、判定結果２０ａをゲートパルス指令生成部２２へ出力する。 (S3) When the current value Isa satisfies the condition of the above expression (3) (S2, Yes), the short-circuit fault detector 20 determines that the diode 11a of the converter circuit 4a is normal, and uses the determination result 20a as a gate pulse command. Output to the generation unit 22.
　（Ｓ４）電流値Ｉｓａが上記（３）式の条件を満たさない場合（Ｓ２，Ｎｏ）、短絡故障検出部２０はコンバータ回路４ａのダイオード１１ａが短絡故障していると判定し、判定結果２０ａをゲートパルス指令生成部２２へ出力する。 (S4) When the current value Isa does not satisfy the condition of the above expression (3) (S2, No), the short-circuit fault detector 20 determines that the diode 11a of the converter circuit 4a has a short-circuit fault, and determines the determination result 20a. Output to the gate pulse command generator 22.
　（Ｓ５）短絡故障検出部２０は下記（４）式によりコンバータ回路４ｂのダイオード１１ｂが短絡故障しているか否かを判定する。
　Ｉｓｂ≧０［Ａ］・・・（４） (S5) The short circuit failure detection unit 20 determines whether or not the diode 11b of the converter circuit 4b has a short circuit failure according to the following equation (4).
Isb ≧ 0 [A] (4)
　（Ｓ６）電流値Ｉｓｂが上記（４）式の条件を満たす場合（Ｓ５，Ｙｅｓ）、短絡故障検出部２０はコンバータ回路４ｂのダイオード１１ｂが正常であると判定し、判定結果２０ａをゲートパルス指令生成部２２へ出力する。 (S6) When the current value Isb satisfies the condition of the above expression (4) (S5, Yes), the short-circuit fault detection unit 20 determines that the diode 11b of the converter circuit 4b is normal and uses the determination result 20a as a gate pulse command. Output to the generation unit 22.
　（Ｓ７）電流値Ｉｓｂが上記（４）式の条件を満たさない場合（Ｓ５，Ｎｏ）、短絡故障検出部２０はコンバータ回路４ｂのダイオード１１ｂが短絡故障していると判定し、判定結果２０ａをゲートパルス指令生成部２２へ出力する。 (S7) When the current value Isb does not satisfy the condition of the above expression (4) (S5, No), the short-circuit fault detection unit 20 determines that the diode 11b of the converter circuit 4b has a short-circuit fault, and determines the determination result 20a. Output to the gate pulse command generator 22.
　（Ｓ８）短絡故障検出部２０は下記（５）式によりコンバータ回路４ｃのダイオード１１ｃが短絡故障しているか否かを判定する。 (S8) The short circuit failure detection unit 20 determines whether or not the diode 11c of the converter circuit 4c has a short circuit failure according to the following equation (5).
　Ｉｓｃ≧０［Ａ］・・・（５） Isc ≧ 0 [A] (5)
　（Ｓ９）電流値Ｉｓｃが上記（５）式の条件を満たす場合（Ｓ８，Ｙｅｓ）、短絡故障検出部２０はコンバータ回路４ｃのダイオード１１ｃが正常であると判定し、判定結果２０ａをゲートパルス指令生成部２２へ出力する。 (S9) When the current value Isc satisfies the condition of the above expression (5) (S8, Yes), the short-circuit fault detection unit 20 determines that the diode 11c of the converter circuit 4c is normal and uses the determination result 20a as a gate pulse command. Output to the generation unit 22.
　（Ｓ１０）電流値Ｉｓｃが上記（５）式の条件を満たさない場合（Ｓ８，Ｎｏ）、短絡故障検出部２０はコンバータ回路４ｃのダイオード１１ｃが短絡故障していると判定し、判定結果２０ａをゲートパルス指令生成部２２へ出力する。 (S10) When the current value Isc does not satisfy the condition of the above expression (5) (S8, No), the short-circuit fault detector 20 determines that the diode 11c of the converter circuit 4c has a short-circuit fault, and determines the determination result 20a. Output to the gate pulse command generator 22.
　（Ｓ１１）短絡故障検出部２０は下記（６）式によりコンバータ回路４ｄのダイオード１１ｄが短絡故障しているか否かを判定する。 (S11) The short circuit failure detection unit 20 determines whether or not the diode 11d of the converter circuit 4d has a short circuit failure according to the following equation (6).
　Ｉｓｄ≧０［Ａ］・・・（６） Isd ≧ 0 [A] (6)
　（Ｓ１２）電流値Ｉｓｄが上記（６）式の条件を満たす場合（Ｓ１１，Ｙｅｓ）、短絡故障検出部２０はコンバータ回路４ｄのダイオード１１ｄが正常であると判定し、判定結果２０ａをゲートパルス指令生成部２２へ出力する。 (S12) When the current value Isd satisfies the condition of the above expression (6) (S11, Yes), the short-circuit fault detection unit 20 determines that the diode 11d of the converter circuit 4d is normal and uses the determination result 20a as a gate pulse command. Output to the generation unit 22.
　（Ｓ１３）電流値Ｉｓｄが上記（６）式の条件を満たさない場合（Ｓ１１，Ｎｏ）、短絡故障検出部２０はコンバータ回路４ｄのダイオード１１ｄが短絡故障していると判定し、判定結果２０ａをゲートパルス指令生成部２２へ出力する。 (S13) When the current value Isd does not satisfy the condition of the above expression (6) (S11, No), the short-circuit fault detection unit 20 determines that the diode 11d of the converter circuit 4d has a short-circuit fault, and determines the determination result 20a. Output to the gate pulse command generator 22.
　（Ｓ１４）ＭＰＰＴ制御部２１はＭＰＰＴ制御により決定された第１のゲートパルス指令２１ａを演算する。 (S14) The MPPT control unit 21 calculates the first gate pulse command 21a determined by the MPPT control.
　（Ｓ１５）ゲートパルス指令生成部２２は、Ｓ２からＳ１２で短絡故障検出部２０から出力された判定結果２０ａにより、ダイオードの短絡故障の有無を判定する。 (S15) The gate pulse command generation unit 22 determines the presence or absence of a short circuit failure of the diode based on the determination result 20a output from the short circuit failure detection unit 20 in S2 to S12.
　（Ｓ１６）ダイオードに短絡故障が有る場合（Ｓ１５，Ｙｅｓ）、ゲートパルス指令生成部２２は、全てのスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄを短絡させるスイッチング素子短絡指令である第２のゲートパルス指令２２ａを生成し、ゲートパルス指令Ｇｓとして複数のゲートパルス発生器１７ａ，１７ｂ，１７ｃ，１７ｄのそれぞれに対して出力する。 (S16) When there is a short-circuit fault in the diode (S15, Yes), the gate pulse command generation unit 22 is a second gate pulse command that is a switching element short-circuit command that short-circuits all the switching elements 10a, 10b, 10c, and 10d. 22a is generated and output as a gate pulse command Gs to each of the plurality of gate pulse generators 17a, 17b, 17c, and 17d.
　（Ｓ１７）ダイオードに短絡故障がない場合（Ｓ１５，Ｎｏ）、ゲートパルス指令生成部２２は、Ｓ１４で演算された第１のゲートパルス指令２１ａを選択し、ゲートパルス指令Ｇｓとして複数のゲートパルス発生器１７ａ，１７ｂ，１７ｃ，１７ｄのそれぞれに対して出力する。 (S17) When there is no short circuit failure in the diode (S15, No), the gate pulse command generation unit 22 selects the first gate pulse command 21a calculated in S14, and generates a plurality of gate pulses as the gate pulse command Gs. Output to each of the devices 17a, 17b, 17c, 17d.
　（Ｓ１８）複数のゲートパルス発生器１７ａ，１７ｂ，１７ｃ，１７ｄは、受信したゲートパルス指令Ｇｓの種類に対応するゲートパルス信号１７ａ１，１７ｂ１，１７ｃ１，１７ｄ１を発生する。すなわち、第１のゲートパルス指令２１ａに対応するゲートパルス指令Ｇｓである場合、太陽電池ストリング１ａから出力された電圧を昇圧させるゲートパルス信号１７ａ１，１７ｂ１，１７ｃ１，１７ｄ１が発生する。第２のゲートパルス指令２２ａに対応するゲートパルス指令Ｇｓである場合、全てのスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄを短絡させるゲートパルス信号１７ａ１，１７ｂ１，１７ｃ１，１７ｄ１が発生する。 (S18) The plurality of gate pulse generators 17a, 17b, 17c, and 17d generate gate pulse signals 17a1, 17b1, 17c1, and 17d1 corresponding to the type of the received gate pulse command Gs. That is, in the case of the gate pulse command Gs corresponding to the first gate pulse command 21a, the gate pulse signals 17a1, 17b1, 17c1, and 17d1 for boosting the voltage output from the solar cell string 1a are generated. When the gate pulse command Gs corresponds to the second gate pulse command 22a, gate pulse signals 17a1, 17b1, 17c1, and 17d1 that short-circuit all the switching elements 10a, 10b, 10c, and 10d are generated.
　以下では系統連系インバータ装置３の動作を具体的な数値を用いて説明する。なお以下で説明する数値は一例であり、系統連系インバータ装置３の動作で用いられる数値はこれらに限定されるものではない。 Hereinafter, the operation of the grid interconnection inverter device 3 will be described using specific numerical values. In addition, the numerical value demonstrated below is an example and the numerical value used by operation | movement of the grid connection inverter apparatus 3 is not limited to these.
　本実施の形態においては、コンバータ回路４ｄのダイオード１１ｄが故障したときを例として説明する。具体的な数値は下記（７）式から（１１）式の通りである。
　Ｖｓａ、Ｖｓｂ、Ｖｓｃ＝３００［Ｖ］・・・（７）
　Ｖｓｄ＝１００［Ｖ］・・・（８）
　Ｉｓａ、Ｉｓｂ、Ｉｓｃ＝５［Ａ］・・・（９）
　Ｉｓｄ＝－３０［Ａ］・・・（１０）
　太陽電池ストリングの短絡電流＝１０［Ａ］・・・（１１） In the present embodiment, a case where the diode 11d of the converter circuit 4d fails will be described as an example. Specific numerical values are as shown in the following formulas (7) to (11).
Vsa, Vsb, Vsc = 300 [V] (7)
Vsd = 100 [V] (8)
Isa, Isb, Isc = 5 [A] (9)
Isd = −30 [A] (10)
Short-circuit current of solar cell string = 10 [A] (11)
　図３に示すフローチャートに従いコンバータ制御部１６の動作を説明する。 The operation of the converter control unit 16 will be described with reference to the flowchart shown in FIG.
　Ｓ１からＳ１３において、入力された電流値がＩｓａ≧０、Ｉｓｂ≧０、Ｉｓｃ≧０、Ｉｓｄ＜０という関係性を有するため、Ｓ１４においてＭＰＰＴ制御部２１では第１のゲートパルス指令２１ａが演算されるが、Ｓ１５においてゲートパルス指令生成部２２は、複数のコンバータ回路４の全てのスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄを短絡する第２のゲートパルス指令２２ａをゲートパルス指令Ｇｓとして出力する。 In S1 to S13, since the input current values have a relationship of Isa ≧ 0, Isb ≧ 0, Isc ≧ 0, Isd <0, the MPPT controller 21 calculates the first gate pulse command 21a in S14. However, in S15, the gate pulse command generation unit 22 outputs the second gate pulse command 22a that short-circuits all the switching elements 10a, 10b, 10c, and 10d of the plurality of converter circuits 4 as the gate pulse command Gs.
　以上に説明したように実施の形態１の系統連系インバータ装置３は、コンバータ回路４ａ，４ｂ，４ｃ，４ｄのそれぞれのダイオード１１ａ，１１ｂ，１１ｃ，１１ｄが短絡故障しているか否かを判定し、ダイオードが短絡故障してないときはＭＰＰＴ制御部２１の制御指令に応じたコンバータ回路のゲートパルス指令を出力し、ダイオードが短絡故障しているときにはコンバータ回路のスイッチング素子を短絡させるゲートパルス指令を出力するように構成されている。特許文献１に示す従来技術のようにコンバータ回路の動作停止だけでは太陽電池への逆電流を防ぐことができず、太陽電池の性能劣化や破損を引き起こす可能性があった。実施の形態１の系統連系インバータ装置３によれば、ダイオードの短絡故障を検出し、コンバータ回路の全てのスイッチング素子を短絡させることで、太陽電池への逆電流を防ぎ、太陽電池の性能劣化または破損を防ぐことができる。 As described above, the grid-connected inverter device 3 of the first embodiment determines whether or not the respective diodes 11a, 11b, 11c, and 11d of the converter circuits 4a, 4b, 4c, and 4d are short-circuited. When the diode is not short-circuited, a gate pulse command for the converter circuit corresponding to the control command of the MPPT control unit 21 is output. When the diode is short-circuited, a gate pulse command for short-circuiting the switching element of the converter circuit is output. It is configured to output. As in the prior art disclosed in Patent Document 1, it is not possible to prevent the reverse current to the solar cell only by stopping the operation of the converter circuit, and there is a possibility of causing the performance deterioration or breakage of the solar cell. According to the grid-connected inverter device 3 of the first embodiment, a diode short-circuit failure is detected, and all switching elements of the converter circuit are short-circuited, thereby preventing a reverse current to the solar cell and degrading the performance of the solar cell. Or damage can be prevented.
実施の形態２．
　実施の形態１に係る系統連系インバータ装置３は、ダイオードが短絡故障を検出したときにコンバータ回路の全てのスイッチング素子を短絡させ、複数の太陽電池ストリング１を全て短絡状態とし、ダイオードが短絡故障したコンバータ回路に接続される太陽電池ストリングに逆電流が流れないように構成されている。実施の形態２に係る系統連系インバータ装置３は、短絡故障したダイオードを備えるコンバータ回路を構成するスイッチング素子を短絡させることにより、当該コンバータ回路に接続される太陽電池ストリングを短絡状態とし、短絡故障していないダイオードを備えるコンバータ回路に接続される太陽電池ストリングには逆電流が流れないように構成されている。本実施の形態２に係る系統連系インバータ装置３の構成は、コンバータ制御部１６における動作を除き、実施の形態１に係る系統連系インバータ装置３と同様であるため説明を省略する。 Embodiment 2. FIG.
In the grid-connected inverter device 3 according to the first embodiment, when the diode detects a short-circuit fault, all the switching elements of the converter circuit are short-circuited, all the plurality of solar cell strings 1 are short-circuited, and the diode is short-circuit fault The reverse current does not flow through the solar cell string connected to the converter circuit. The grid-connected inverter device 3 according to the second embodiment short-circuits the switching element that constitutes the converter circuit including the short-circuited diode, thereby bringing the solar cell string connected to the converter circuit into a short-circuited state, thereby causing a short-circuit fault. A reverse current does not flow through the solar cell string connected to the converter circuit including the non-connected diode. The configuration of the grid interconnection inverter device 3 according to the second embodiment is the same as that of the grid interconnection inverter device 3 according to the first embodiment except for the operation in the converter control unit 16, and thus the description thereof is omitted.
　図４は本発明の実施の形態２に係る系統連系インバータ装置のコンバータ制御部によるダイオード短絡故障判定時の動作に係わるフローチャートである。図３に示すフローチャートと異なる点はＳ１６，Ｓ１８の処理がＳ２６，Ｓ２８の処理に置き換わる点である。実施の形態２では、複数のコンバータ回路４ａ，４ｂ，４ｃ，４ｄの内、コンバータ回路４ａを構成するダイオード１１ａに短絡故障が発生し、コンバータ回路４ｂ，４ｃ，４ｄを構成するダイオード１１ｂ，１１ｃ，１１ｄには短絡故障が発生していないと仮定する。 FIG. 4 is a flowchart relating to the operation at the time of determining a diode short-circuit fault by the converter control unit of the grid-connected inverter device according to the second embodiment of the present invention. The difference from the flowchart shown in FIG. 3 is that the processes of S16 and S18 are replaced with the processes of S26 and S28. In the second embodiment, among the plurality of converter circuits 4a, 4b, 4c, and 4d, a short circuit failure occurs in the diode 11a that constitutes the converter circuit 4a, and the diodes 11b, 11c, and 11b that constitute the converter circuits 4b, 4c, and 4d, It is assumed that no short circuit fault has occurred in 11d.
　（Ｓ２６）ダイオード１１ａに短絡故障が有る場合（Ｓ１５，Ｙｅｓ）、ゲートパルス指令生成部２２は、スイッチング素子１０ａを短絡させるスイッチング素子短絡指令である第２のゲートパルス指令２２ａを生成し、ゲートパルス指令Ｇｓとしてゲートパルス発生器１７ａに対して出力する。 (S26) When there is a short circuit fault in the diode 11a (S15, Yes), the gate pulse command generation unit 22 generates a second gate pulse command 22a that is a switching element short circuit command for short-circuiting the switching element 10a. The command Gs is output to the gate pulse generator 17a.
　（Ｓ２８）当該ゲートパルス指令Ｇｓを受信したゲートパルス発生器１７ａは、スイッチング素子１０ａを短絡させるゲートパルス信号１７ａ１を発生する。 (S28) The gate pulse generator 17a that has received the gate pulse command Gs generates a gate pulse signal 17a1 for short-circuiting the switching element 10a.
　当該ゲートパルス信号１７ａ１が発生することにより、短絡故障したダイオード１１ａを備えるコンバータ回路４ａに接続される太陽電池ストリング１ａは短絡状態となる。さらに正常なダイオードを備えるコンバータ回路４ｂ，４ｃ，４ｄに接続される太陽電池ストリング１ｂ，１ｃ，１ｄから出力される電流は、短絡故障したダイオード１１ａを備えるコンバータ回路４ａを構成するスイッチング素子１０ａに流れるため、太陽電池ストリング１ｂ，１ｃ，１ｄには逆電流が流れない。そのため太陽電池の性能劣化または破損を防ぐことができる。また実施の形態２に係る系統連系インバータ装置３によれば、少なくとも、短絡故障したダイオードを備えるコンバータ回路を構成するスイッチング素子のみ短絡させる構成であるため、実施の形態１に比べてコンバータ制御部１６によるゲートパルス指令Ｇｓの生成動作を簡略化できる。 When the gate pulse signal 17a1 is generated, the solar cell string 1a connected to the converter circuit 4a including the short-circuited diode 11a is short-circuited. Furthermore, the current output from the solar cell strings 1b, 1c, 1d connected to the converter circuits 4b, 4c, 4d having normal diodes flows to the switching element 10a constituting the converter circuit 4a having the short-circuited diode 11a. Therefore, no reverse current flows through the solar cell strings 1b, 1c, 1d. Therefore, the performance deterioration or damage of the solar cell can be prevented. Further, according to the grid-connected inverter device 3 according to the second embodiment, since at least the switching element constituting the converter circuit including the short-circuited diode is short-circuited, the converter control unit is compared with the first embodiment. The generation operation of the gate pulse command Gs by 16 can be simplified.
　なお実施の形態２に係る系統連系インバータ装置３は、短絡故障したダイオードを備えるコンバータ回路のスイッチング素子のみ短絡させる構成としているが、短絡させるスイッチング素子は、短絡故障したダイオードを備えるコンバータ回路のスイッチング素子を含めればよく、短絡故障していないダイオードを備えるコンバータ回路のスイッチング素子を１つ以上含めても同様の効果を得ることができる。 In addition, although the grid connection inverter apparatus 3 which concerns on Embodiment 2 is set as the structure which short-circuits only the switching element of a converter circuit provided with the short-circuited diode, the switching element to be short-circuited is switching of the converter circuit provided with the short-circuited diode The same effect can be obtained even if one or more switching elements of a converter circuit including a diode that is not short-circuited are included.
実施の形態３．
　実施の形態１に係る系統連系インバータ装置３では、系統連系インバータ装置３を構成する機器の駆動電力が商用電力系統２から供給される電力により生成される。しかしながら系統連系インバータ装置３に接続される直流電源が太陽電池ストリング１である場合、太陽電池ストリング１から供給される電力により、系統連系インバータ装置３を構成する機器の駆動電力を生成するのが一般的である。実施の形態１に係る系統連系インバータ装置３が、太陽電池ストリング１から供給される電力により当該駆動電力を生成するように構成されている場合、実施の形態１に係る系統連系インバータ装置３では、複数のコンバータ回路４の全てのスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄを短絡させたときに、複数の太陽電池ストリング１のそれぞれが短絡状態となる。そのため複数の太陽電池ストリング１で発電された電力を系統連系インバータ装置３に供給することができず、複数のコンバータ回路４のそれぞれのスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄがＯＦＦしてしまう。このため実施の形態３に係る系統連系インバータ装置３は、複数の太陽電池ストリング１で発電された電力により当該駆動電力を生成する構成において、以下に説明する動作により逆電流を防止する。なお本実施の形態３に係る系統連系インバータ装置３の構成は、コンバータ制御部１６における動作を除き、実施の形態１に係る系統連系インバータ装置３と同様であるため説明を省略する。 Embodiment 3 FIG.
In the grid interconnection inverter device 3 according to the first embodiment, the drive power of the equipment constituting the grid interconnection inverter device 3 is generated by the power supplied from the commercial power grid 2. However, when the DC power source connected to the grid-connected inverter device 3 is the solar cell string 1, the driving power of the equipment constituting the grid-connected inverter device 3 is generated by the power supplied from the solar cell string 1. Is common. When the grid connection inverter apparatus 3 which concerns on Embodiment 1 is comprised so that the said drive power may be produced | generated with the electric power supplied from the solar cell string 1, the grid connection inverter apparatus 3 which concerns on Embodiment 1 Then, when all the switching elements 10a, 10b, 10c, and 10d of the plurality of converter circuits 4 are short-circuited, each of the plurality of solar cell strings 1 is short-circuited. Therefore, the electric power generated by the plurality of solar cell strings 1 cannot be supplied to the grid interconnection inverter device 3, and the switching elements 10a, 10b, 10c, and 10d of the plurality of converter circuits 4 are turned off. For this reason, the grid interconnection inverter device 3 according to Embodiment 3 prevents the reverse current by the operation described below in the configuration in which the driving power is generated by the power generated by the plurality of solar cell strings 1. Note that the configuration of the grid interconnection inverter device 3 according to the third embodiment is the same as that of the grid interconnection inverter device 3 according to the first embodiment except for the operation in the converter control unit 16, and thus the description thereof is omitted.
　図５は本発明の実施の形態３に係る系統連系インバータ装置のコンバータ制御部によるダイオード短絡故障判定時の動作に係わるフローチャートである。図３に示すフローチャートと異なる点はＳ１６，Ｓ１８の処理がＳ３６，Ｓ２８の処理に置き換わる点である。実施の形態３では、複数のコンバータ回路４ａ，４ｂ，４ｃ，４ｄの内、コンバータ回路４ａを構成するダイオード１１ａに短絡故障が発生し、コンバータ回路４ｂ，４ｃ，４ｄを構成するダイオード１１ｂ，１１ｃ，１１ｄには短絡故障が発生していないと仮定する。 FIG. 5 is a flowchart relating to the operation at the time of determining a diode short-circuit fault by the converter control unit of the grid-connected inverter device according to the third embodiment of the present invention. The difference from the flowchart shown in FIG. 3 is that the processes of S16 and S18 are replaced with the processes of S36 and S28. In the third embodiment, among the plurality of converter circuits 4a, 4b, 4c, and 4d, a short circuit fault occurs in the diode 11a that constitutes the converter circuit 4a, and the diodes 11b, 11c, and 11b that constitute the converter circuits 4b, 4c, and 4d, It is assumed that no short circuit fault has occurred in 11d.
　（Ｓ３６）ダイオード１１ａに短絡故障が有る場合（Ｓ１５，Ｙｅｓ）、ゲートパルス指令生成部２２は、短絡故障していないダイオード１１ｂ，１１ｃ，１１ｄを備えるコンバータ回路４ｂ，４ｃ，４ｄを構成するスイッチング素子１０ｂ，１０ｃ，１０ｄを短絡させるスイッチング素子短絡指令である第２のゲートパルス指令２２ａを生成し、ゲートパルス指令Ｇｓとしてゲートパルス発生器１７ｂ，１７ｃ，１７ｄのそれぞれに対して出力する。 (S36) When the diode 11a has a short-circuit failure (S15, Yes), the gate pulse command generation unit 22 is a switching element that constitutes the converter circuits 4b, 4c, and 4d including the diodes 11b, 11c, and 11d that are not short-circuited. A second gate pulse command 22a, which is a switching element short-circuit command for short- circuiting 10b, 10c, and 10d, is generated and output as a gate pulse command Gs to each of the gate pulse generators 17b, 17c, and 17d.
　（Ｓ３８）当該ゲートパルス指令Ｇｓを受信したゲートパルス発生器１７ｂ，１７ｃ，１７ｄのそれぞれは、受信したゲートパルス指令Ｇｓの種類に対応するゲートパルス信号を生成して出力する。すなわち、第１のゲートパルス指令２１ａに対応するゲートパルス指令Ｇｓである場合、太陽電池ストリング１ｂ，１ｃ，１ｄから出力された電圧を昇圧させるゲートパルス信号１７ｂ１，１７ｃ１，１７ｄ１が出力される。第２のゲートパルス指令２２ａに対応するゲートパルス指令Ｇｓである場合、スイッチング素子１０ｂ，１０ｃ，１０ｄを短絡させるゲートパルス信号１７ａ１が発生する。 (S38) Each of the gate pulse generators 17b, 17c, 17d receiving the gate pulse command Gs generates and outputs a gate pulse signal corresponding to the type of the received gate pulse command Gs. That is, in the case of the gate pulse command Gs corresponding to the first gate pulse command 21a, the gate pulse signals 17b1, 17c1, and 17d1 that boost the voltage output from the solar cell strings 1b, 1c, and 1d are output. When the gate pulse command Gs corresponds to the second gate pulse command 22a, a gate pulse signal 17a1 for short-circuiting the switching elements 10b, 10c, and 10d is generated.
　スイッチング素子１０ｂ，１０ｃ，１０ｄを短絡することにより、短絡故障していないダイオード１１ｂ，１１ｃ，１１ｄを備えるコンバータ回路４ｂ，４ｃ，４ｄに接続される太陽電池ストリング１ｂ，１ｃ，１ｄから出力される電流は、短絡故障していないダイオード１１ｂ，１１ｃ，１１ｄを備えるコンバータ回路４ｂ，４ｃ，４ｄを構成するスイッチング素子１０ｂ，１０ｃ，１０ｄに流れるが、短絡故障したダイオード１１ａを備えるコンバータ回路４ａに接続された太陽電池ストリング１ａには逆電流が流れない。 By short-circuiting the switching elements 10b, 10c, 10d, currents output from the solar cell strings 1b, 1c, 1d connected to the converter circuits 4b, 4c, 4d including the diodes 11b, 11c, 11d that are not short-circuited Flows through the switching elements 10b, 10c and 10d constituting the converter circuits 4b, 4c and 4d including the diodes 11b, 11c and 11d which are not short-circuited, but is connected to the converter circuit 4a including the diode 11a which is short-circuited. No reverse current flows through the solar cell string 1a.
　ダイオード１１ａが短絡故障することにより太陽電池ストリング１ａは短絡状態となるため、太陽電池ストリング１ａの出力電圧は低下するが、ダイオード１１ａは正常であるため、太陽電池ストリング１ａから出力される電流がブロックされる。そのため太陽電池ストリング１ａへの逆電流は発生せず、太陽電池ストリング１ａから供給される電力により上記の駆動電力を生成することができる。 Since the solar cell string 1a is short-circuited due to the short-circuit failure of the diode 11a, the output voltage of the solar cell string 1a is reduced. However, since the diode 11a is normal, the current output from the solar cell string 1a is blocked. Is done. Therefore, the reverse current to the solar cell string 1a does not occur, and the driving power can be generated by the power supplied from the solar cell string 1a.
　実施の形態３に係る系統連系インバータ装置３によれば、系統連系インバータ装置３の構成機器を太陽電池ストリングの電力で駆動する場合においても、スイッチング素子の短絡状態を保持し続けることができ、太陽電池の性能劣化または破損を防ぐことができる。 According to the grid interconnection inverter device 3 according to the third embodiment, even when the components of the grid interconnection inverter device 3 are driven by the power of the solar cell string, the short circuit state of the switching element can be maintained. The performance deterioration or damage of the solar cell can be prevented.
　なお実施の形態１から３に係る系統連系インバータ装置３が備えるスイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄとして、炭化珪素（Ｓｉｌｉｃｏｎ　Ｃａｒｂｉｄｅ：ＳｉＣ）を用いて構成されたＭＯＳＦＥＴを用いることにより、以下の効果を得ることができる。ダイオードの短絡故障が検出されて短絡制御されたスイッチング素子には電流が流れるため、スイッチング素子のＯＮ抵抗による損失に起因した熱が発生する。スイッチング素子１０ａ，１０ｂ，１０ｃ，１０ｄとして、炭化珪素を用いて構成されたＭＯＳＦＥＴを用いることにより、ＯＮ抵抗を下げることができ、発熱を抑えることができる。またダイオードの短絡故障検出時における発熱を抑えることができるため、コンバータ回路４ａ，４ｂ，４ｃ，４ｄのそれぞれに接続される不図示の放熱器を小型化でき、系統連系インバータ装置３の重量を軽くすることができる。 In addition, by using MOSFET comprised using silicon carbide (Silicon Carbide: SiC) as switching element 10a, 10b, 10c, 10d with which the grid connection inverter apparatus 3 which concerns on Embodiment 1-3 is equipped, the following An effect can be obtained. Since a current flows through the switching element in which a short-circuit fault of the diode is detected and short-circuited, heat is generated due to a loss due to the ON resistance of the switching element. By using MOSFETs made of silicon carbide as the switching elements 10a, 10b, 10c, and 10d, the ON resistance can be lowered and heat generation can be suppressed. Further, since heat generation at the time of detecting a short circuit failure of the diode can be suppressed, a radiator (not shown) connected to each of the converter circuits 4a, 4b, 4c, 4d can be reduced in size, and the weight of the grid interconnection inverter device 3 can be reduced. Can be lightened.
　以上の実施の形態に示した構成は、本発明の内容の一例を示すものであり、別の公知の技術と組み合わせることも可能であるし、本発明の要旨を逸脱しない範囲で、構成の一部を省略、変更することも可能である。 The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.
　１ａ，１ｂ，１ｃ，１ｄ　太陽電池ストリング、２　商用電力系統、３　系統連系インバータ装置、４ａ，４ｂ，４ｃ，４ｄ　コンバータ回路、５　インバータ回路、６　出力リレー、７ａ，７ｂ，７ｃ，７ｄ，８　平滑用コンデンサ、９ａ，９ｂ，９ｃ，９ｄ　リアクトル、１０ａ，１０ｂ，１０ｃ，１０ｄ　スイッチング素子、１１ａ，１１ｂ，１１ｃ，１１ｄ　ダイオード、１２ａ，１２ｂ，１２ｃ，１２ｄ　電流検出器、１３ａ，１３ｂ，１３ｃ，１３ｄ　電圧検出器、１６　コンバータ制御部、１７ａ，１７ｂ，１７ｃ，１７ｄ　ゲートパルス発生器、１７ａ１，１７ｂ１，１７ｃ１，１７ｄ１　ゲートパルス信号、２０　短絡故障検出部、２０ａ　判定結果、２１　ＭＰＰＴ制御部、２１ａ　第１のゲートパルス指令、２２　ゲートパルス指令生成部、２２ａ　第２のゲートパルス指令、３０ａ，３０ｂ，３０ｃ，３０ｄ　電流検出素子、１００　太陽光発電システム、１０１ａ，１０１ｂ，１０１ｃ，１０１ｄ　正極入力端子、１０２ａ，１０２ｂ，１０２ｃ，１０２ｄ　負極入力端子、１０３，１０４　系統出力端子、２００　制御部。 1a, 1b, 1c, 1d solar cell string, 2 commercial power system, 3 grid interconnection inverter device, 4a, 4b, 4c, 4d converter circuit, 5 inverter circuit, 6 output relay, 7a, 7b, 7c, 7d, 8 Smoothing capacitor, 9a, 9b, 9c, 9d reactor, 10a, 10b, 10c, 10d switching element, 11a, 11b, 11c, 11d diode, 12a, 12b, 12c, 12d current detector, 13a, 13b, 13c, 13d Voltage detector, 16 converter control unit, 17a, 17b, 17c, 17d gate pulse generator, 17a1, 17b1, 17c1, 17d1 gate pulse signal, 20 short-circuit fault detection unit, 20a determination result, 21 MPPT control unit, 21a first Gate pulse command, 22 Auto pulse command generator, 22a second gate pulse command, 30a, 30b, 30c, 30d current detection element, 100 solar power generation system, 101a, 101b, 101c, 101d positive input terminal, 102a, 102b, 102c, 102d negative input Terminal, 103, 104 system output terminal, 200 control unit.

Claims (8)

  1. 　複数の直流電源のそれぞれから出力される電力が入力される複数のコンバータ回路と、前記複数のコンバータ回路のそれぞれから出力される直流電圧を交流電圧へ変換するインバータ回路とを備えた系統連系インバータ装置であって、
    　前記複数のコンバータ回路のぞれぞれを構成するダイオードの短絡故障を検出する短絡故障検出部と、
    　前記短絡故障検出部が前記ダイオードの短絡故障を検出したとき、前記複数のコンバータ回路のぞれぞれを構成するスイッチング素子を制御するためのゲートパルス指令を出力するゲートパルス指令生成部と
    　を備えることを特徴とする系統連系インバータ装置。     A grid-connected inverter comprising a plurality of converter circuits to which electric power output from each of a plurality of DC power supplies is input, and an inverter circuit that converts a DC voltage output from each of the plurality of converter circuits into an AC voltage A device,
    A short-circuit fault detection unit for detecting a short-circuit fault of a diode constituting each of the plurality of converter circuits;
    A gate pulse command generation unit that outputs a gate pulse command for controlling a switching element that constitutes each of the plurality of converter circuits when the short-circuit fault detection unit detects a short-circuit fault of the diode; A grid-connected inverter device characterized by that.
  2. 　前記短絡故障検出部が前記ダイオードの短絡故障を検出したとき、
    　前記ゲートパルス指令生成部は、前記複数のコンバータ回路のぞれぞれを構成するスイッチング素子の何れかを短絡させるためのゲートパルス指令を出力することを特徴とする請求項１に記載の系統連系インバータ装置。     When the short-circuit fault detection unit detects a short-circuit fault of the diode,
    2. The system link according to claim 1, wherein the gate pulse command generation unit outputs a gate pulse command for short-circuiting any one of the switching elements constituting each of the plurality of converter circuits. System inverter device.
  3. 　前記短絡故障検出部が前記ダイオードの短絡故障を検出したとき、
    　前記ゲートパルス指令生成部は、前記複数のコンバータ回路のぞれぞれを構成するスイッチング素子の全てを短絡させるためのゲートパルス指令を出力することを特徴とする請求項１に記載の系統連系インバータ装置。     When the short-circuit fault detection unit detects a short-circuit fault of the diode,
    2. The grid interconnection according to claim 1, wherein the gate pulse command generation unit outputs a gate pulse command for short-circuiting all of the switching elements constituting each of the plurality of converter circuits. Inverter device.
  4. 　前記短絡故障検出部が前記ダイオードの短絡故障を検出したとき、
    　前記ゲートパルス指令生成部は、前記複数のコンバータ回路のぞれぞれを構成するスイッチング素子の内、短絡故障した前記ダイオードを備えるコンバータ回路を構成するスイッチング素子を短絡させるためのゲートパルス指令を出力することを特徴とする請求項１に記載の系統連系インバータ装置。     When the short-circuit fault detection unit detects a short-circuit fault of the diode,
    The gate pulse command generation unit outputs a gate pulse command for short-circuiting a switching element constituting the converter circuit including the diode that is short-circuited among the switching elements constituting each of the plurality of converter circuits. The grid-connected inverter device according to claim 1, wherein:
  5. 　前記短絡故障検出部が前記ダイオードの短絡故障を検出したとき、
    　前記ゲートパルス指令生成部は、前記複数のコンバータ回路のぞれぞれを構成するスイッチング素子の内、短絡故障していない前記ダイオードを備えるコンバータ回路を構成するスイッチング素子を短絡させるためのゲートパルス指令を出力することを特徴とする請求項１に記載の系統連系インバータ装置。     When the short-circuit fault detection unit detects a short-circuit fault of the diode,
    The gate pulse command generation unit is configured to short-circuit a switching element constituting the converter circuit including the diode that is not short-circuited out of the switching elements constituting each of the plurality of converter circuits. The grid-connected inverter device according to claim 1, wherein
  6. 　前記短絡故障検出部は、前記複数の直流電源のそれぞれから出力される電流値に基づき、前記複数のコンバータ回路のぞれぞれを構成するダイオードの短絡故障の有無を判定することを特徴とする請求項１から請求項５の何れか一項に記載の系統連系インバータ装置。 The short-circuit fault detection unit determines whether or not there is a short-circuit fault of a diode constituting each of the plurality of converter circuits, based on a current value output from each of the plurality of DC power supplies. The grid connection inverter apparatus as described in any one of Claims 1-5.
  7. 　複数の太陽電池のそれぞれから出力される電力が入力される複数のコンバータ回路と、前記複数のコンバータ回路のそれぞれから出力される直流電圧を交流電圧へ変換するインバータ回路とを備え、前記太陽電池から供給される電力により前記系統連系インバータ装置を構成する機器の駆動電源を生成する系統連系インバータ装置であって、
    　前記短絡故障検出部がダイオード短絡故障を検知したとき、
    　前記ゲートパルス指令生成部は、短絡故障した前記ダイオードを備えるコンバータ回路を構成するスイッチング素子の動作を停止させ、かつ、短絡故障していない前記ダイオードを備えるコンバータ回路を構成するスイッチング素子を短絡させるためのゲートパルス指令を出力することを特徴とする系統連系インバータ装置。     A plurality of converter circuits to which electric power output from each of the plurality of solar cells is input; and an inverter circuit that converts a DC voltage output from each of the plurality of converter circuits into an AC voltage; A grid-connected inverter device that generates a drive power source of equipment that constitutes the grid-connected inverter device with supplied power,
    When the short-circuit fault detector detects a diode short-circuit fault,
    The gate pulse command generation unit is configured to stop the operation of the switching element that constitutes the converter circuit including the diode that is short-circuited and to short-circuit the switching element that constitutes the converter circuit including the diode that is not short-circuited. A grid-connected inverter device that outputs a gate pulse command.
  8. 　前記スイッチング素子として炭化珪素を用いて構成されたＭＯＳＦＥＴを用いることを特徴とする請求項１から請求項７の何れか一項に記載の系統連系インバータ装置。 A grid-connected inverter device according to any one of claims 1 to 7, wherein a MOSFET configured using silicon carbide is used as the switching element.
PCT/JP2016/067055 2016-06-08 2016-06-08 Grid-connected inverter device WO2017212572A1 (en)

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