WO2018087813A1 - Appareil d'onduleur d'interconnexion de systèmes - Google Patents

Appareil d'onduleur d'interconnexion de systèmes Download PDF

Info

Publication number
WO2018087813A1
WO2018087813A1 PCT/JP2016/083110 JP2016083110W WO2018087813A1 WO 2018087813 A1 WO2018087813 A1 WO 2018087813A1 JP 2016083110 W JP2016083110 W JP 2016083110W WO 2018087813 A1 WO2018087813 A1 WO 2018087813A1
Authority
WO
WIPO (PCT)
Prior art keywords
voltage
operation mode
converter circuit
power
boost
Prior art date
Application number
PCT/JP2016/083110
Other languages
English (en)
Japanese (ja)
Inventor
一平 竹内
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2016/083110 priority Critical patent/WO2018087813A1/fr
Priority to JP2017518563A priority patent/JP6195690B1/ja
Publication of WO2018087813A1 publication Critical patent/WO2018087813A1/fr

Links

Images

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/66—Regulating electric power
    • G05F1/67—Regulating electric power to the maximum power available from a generator, e.g. from solar cell
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Definitions

  • the present invention relates to a grid-connected inverter device configured to be capable of being linked to a commercial power system.
  • the grid-connected inverter device includes a step-up / step-down converter that steps up / down the DC power generated by the solar cell string, and an inverter circuit that converts the DC power output from the step-up / down converter to AC power and outputs the AC power to the commercial power system.
  • the target voltage for the boost operation is set based on the system voltage and the inverter output current
  • the step-down operation start voltage is set to a voltage higher than the target voltage.
  • the operation state of the buck-boost converter is controlled to switch to any one of the step-up operation mode, the bypass operation mode, and the step-down operation mode according to the solar cell output voltage.
  • the converter circuit which is a step-up / down converter, controls the output voltage to be ( ⁇ 2 ⁇ system voltage + 35) [V] in order to operate the inverter circuit normally.
  • the number of solar cell strings assumed in Patent Document 1 is one.
  • the number of solar cell strings is plural, the problem described below is recalled.
  • the number of strings of solar cells is 3, and the system voltage is 200 [V].
  • the output voltage of the first solar cell string is 330 [V]
  • the output voltage of the second solar cell string is 310 [V]
  • the output voltage of the third solar cell string is 280 [V].
  • the first converter circuit connected to the first solar cell string is in the bypass operation mode.
  • the second and third converter circuits connected to the second and third solar cell strings are boosted. It becomes an operation mode.
  • the first to third converter circuits operate in the designated operation mode to perform control to follow the maximum power point for each solar cell string.
  • the output voltage of the first solar cell string is 340 [V]
  • the output voltage of the second solar cell string is 330 [V]
  • the output voltage of the third solar cell string is 320 [V].
  • the first to third converter circuits that is, all the converter circuits
  • the bypass operation mode the maximum power point of each solar cell string cannot be individually controlled. Therefore, the first converter circuit to which the first solar cell string having the largest input voltage is connected is operated in the bypass operation mode, and the first and second to which the second and third solar cell strings are connected. It is necessary to modify the control method such that the converter circuit is operated in the step-up operation mode.
  • each converter circuit can operate in the bypass operation mode.
  • the input voltage to each converter circuit differs by about a comma number V for each converter circuit.
  • Patent Document 1 it is necessary to modify the operation mode according to various operation conditions, and it is not possible to operate a plurality of converter circuits in the bypass operation mode. For this reason, the technique of Patent Document 1 has a problem that the conversion efficiency of the converter circuit may be reduced.
  • the present invention has been made in view of the above, and provides a grid-connected inverter device that enables control of operating a plurality of converter circuits in a bypass operation mode and further improves the conversion efficiency of the converter circuits.
  • the purpose is to obtain.
  • the present invention is a grid-connected inverter device configured to be able to be linked to a commercial power system, and the power output from each of a plurality of DC power sources is A plurality of input converter circuits, an inverter circuit that converts a DC voltage output from each of the plurality of converter circuits into an AC voltage, and a first power supply voltage that is an output voltage of the DC power supply for each of the plurality of DC power supplies A voltage detector; a current detector that detects a power supply current that is an output current of a DC power supply for each of a plurality of DC power supplies; a second voltage detector that detects a system voltage applied to an inverter circuit by a commercial power system; and a power supply A controller that determines whether to stop or prohibit the boosting operation of the plurality of converter circuits using the voltage, the power supply current, and the system voltage is provided.
  • the conversion efficiency of the converter circuit can be further improved through the control of operating the plurality of converter circuits in the bypass operation mode.
  • FIG. 11 shows combinations of operating conditions and operating modes of the boost converter circuit in the first embodiment.
  • FIG. 11 shows combinations of operating conditions and operating modes of the boost converter circuit in the first embodiment.
  • FIG. 11 shows combinations of operating conditions and operating modes of the boost converter circuit in the first embodiment.
  • Flowchart for explaining the operation of the controller in the first embodiment Detailed view of the configuration of the controller in the second embodiment
  • the figure which shows the combination of the operation condition and operation mode in the boost converter circuit in the second embodiment The figure which shows the relationship between the characteristic of the solar cell string and the power change rate Flowchart for explaining the operation of the controller in the second embodiment
  • FIG. 1 is a configuration diagram illustrating a photovoltaic power generation system including a grid interconnection inverter device according to the first embodiment.
  • the photovoltaic power generation system 100 includes a plurality of solar battery strings 1 a, 1 b, and 1 c that are DC power supplies, and a grid-connected inverter device 3 to which the plurality of solar battery strings 1 a, 1 b, and 1 c are connected. And comprising.
  • a generic name or any one of the plurality of solar cell strings 1a, 1b, and 1c may be referred to as “solar cell string 1”.
  • Each of the plurality of solar cell strings 1 is a solar cell power source having a configuration in which a plurality of solar cells (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 plurality of boost converter circuits 4a, 4b, 4c to which power output from each of the plurality of solar cell strings 1a, 1b, 1c is input, and a plurality of boost converter circuits 4a, 4b, 4c includes an inverter circuit 5 that converts a DC voltage output from each of 4c into an AC voltage, and a controller 16 that controls each of the plurality of boost converter circuits 4a, 4b, and 4c.
  • the controller 16 generates gate pulse commands Gsa, Gsb, Gsc for controlling each of the plurality of boost converter circuits 4a, 4b, 4c, and for each of the plurality of gate pulse generators 18a, 18b, 18c. Output.
  • a generic name or any one of the plurality of boost converter circuits 4a, 4b, and 4c may be referred to as “boost converter circuit 4”.
  • a generic name or any one of the plurality of gate pulse generators 18a, 18b, and 18c may be referred to as “gate pulse generator 18”.
  • the grid interconnection inverter device 3 includes a plurality of positive input terminals 101a, 101b, 101c, a plurality of negative input terminals 102a, 102b, 102c, and system input / 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 and 1c are connected to the positive electrode input terminals 101b and 101c, respectively.
  • the negative electrode output terminals of the solar cell strings 1b and 1c are connected to the negative electrode input terminals 102b and 102c, respectively.
  • Two system connection lines 41 and 42 connected to the commercial power system 2 are connected to the system input / output terminals 103 and 104, respectively.
  • the grid interconnection inverter device 3 includes a plurality of smoothing capacitors 7a, 7b, 7c, a plurality of boost 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 applied to the boost converter circuit 4a.
  • One end of the smoothing capacitor 7a is connected to the positive input terminal 101a and the positive input terminal of the boost converter circuit 4a via the positive DC bus P.
  • the other end of the smoothing capacitor 7a is connected to the negative input terminal 102a and the negative input terminal of the boost converter circuit 4a via the negative DC bus N.
  • the boost 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 boost 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 boost 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 18a1 output from the gate pulse generator 18a is input to the gate of the switching element 10a.
  • the gate pulse signal 18a1 is a signal that boosts the voltage output from the solar cell string 1a to a voltage necessary for the inverter circuit 5 to generate an AC voltage.
  • the gate pulse generator 18a outputs a gate pulse signal 18a1 to the switching element 10a based on the gate pulse command Gsa output from the controller 16. Details of the operation in the gate pulse generator 18a will be described later.
  • the smoothing capacitor 7b smoothes the DC voltage output from the solar cell string 1b and applied to the boost converter circuit 4b.
  • One end of the smoothing capacitor 7b is connected to the positive input terminal 101b and the positive input terminal of the boost 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 terminal of the boost converter circuit 4b via the negative DC bus N.
  • Boost converter circuit 4b has a reactor 9b, a switching element 10b, and a diode 11b.
  • One end of the reactor 9b is a positive input terminal of the boost 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 boost 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 18b1 output from the gate pulse generator 18b is input to the gate of the switching element 10b.
  • the gate pulse signal 18b1 is a signal that boosts the voltage output from the solar cell string 1b to a voltage necessary for the inverter circuit 5 to generate an AC voltage.
  • the gate pulse generator 18b outputs a gate pulse signal 18b1 to the switching element 10b based on the gate pulse command Gsb output from the controller 16. Details of the operation of the gate pulse generator 18b will be described later.
  • the smoothing capacitor 7c smoothes the DC voltage output from the solar cell string 1c and input to the boost converter circuit 4c.
  • One end of the smoothing capacitor 7c is connected to the positive input terminal 101c and the positive input terminal of the step-up converter circuit 4c through a 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 boost converter circuit 4c via the negative DC bus N.
  • Boost converter circuit 4c has a reactor 9c, a switching element 10c and a diode 11c.
  • One end of the reactor 9c is a positive input terminal of the boost 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 the positive output terminal of the boost 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 18c1 output from the gate pulse generator 18c is input to the gate of the switching element 10c.
  • the gate pulse signal 18c1 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.
  • the gate pulse generator 18c outputs a gate pulse signal 18c1 to the switching element 10c based on the gate pulse command Gsc output from the controller 16. Details of the operation of the gate pulse generator 18c will be described later.
  • One end of the smoothing capacitor 8 is connected to the cathodes of the plurality of diodes 11 a, 11 b, 11 c 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 and the negative input terminal of the inverter circuit 5.
  • Smoothing capacitor 8 smoothes the DC voltage output from each of the plurality of boost converter circuits 4 and applied to inverter circuit 5.
  • the inverter circuit 5 performs an operation of converting a DC voltage charged in the smoothing capacitor 8 into an AC voltage.
  • the AC output terminal of the inverter circuit 5 is connected to the system input / 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 input / 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, a plurality of voltage detectors 13a, 13b, 13c, 15 and a plurality of power calculators 14a, 14b, 14c.
  • each of the voltage detectors 13a, 13b, and 13c constitutes a first current detector
  • the voltage detector 15 constitutes a second voltage detector.
  • a current detection element 32a is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102a and the boost converter circuit 4a.
  • the current detection element 32a detects a current value at the position.
  • a current transformer or a shunt resistor is used for the current detection element 32a.
  • the current detector 12a is realized by an amplifier or a level shift circuit.
  • the current detector 12a detects the output current of the solar cell string 1a, that is, the power supply current.
  • the current detector 12a converts a voltage that is directly proportional to the current detected by the current detection element 32a into a current detection voltage within a low voltage range that can be handled by the power calculator 14a. This current detection voltage corresponds to the current value Isa of the output current of the solar cell string 1a.
  • the current value Isa detected by the current detector 12a is output to the power calculator 14a.
  • 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 output voltage of the solar cell string 1a, that is, the power supply voltage.
  • the voltage value detected by the voltage detector 13a is defined as Vsa.
  • the voltage value Vsa detected by the voltage detector 13a is output to the controller 16 and the power calculator 14a.
  • the power calculator 14a receives the current value Isa output from the current detector 12a and the voltage value Vsa output from the voltage detector 13a.
  • the power calculator 14a calculates a power value Psa input to the boost converter circuit 4a based on the current value Isa and the voltage value Vsa.
  • the calculated power value Psa is output to the controller 16.
  • a current detection element 32b is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102b and the boost converter circuit 4b.
  • the current detection element 32b detects a current value at the position.
  • a current transformer or a shunt resistor is used for the current detection element 32b.
  • the current detector 12b is realized by an amplifier or a level shift circuit.
  • the current detector 12b detects the output current of the solar cell string 1b, that is, the power supply current.
  • the current detector 12b converts a voltage that is directly proportional to the current detected by the current detection element 32b into a current detection voltage within a low voltage range that can be handled by the power calculator 14b. This current detection voltage corresponds to the current value Isb of the output current of the solar cell string 1b.
  • the current value Isb detected by the current detector 12b is output to the power calculator 14b.
  • 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 the output voltage value of the solar cell string 1b, that is, the power supply voltage.
  • the voltage value detected by the voltage detector 13b is defined as Vsb.
  • the voltage value Vsb detected by the voltage detector 13b is output to the controller 16 and the power calculator 14b.
  • the power calculator 14b receives the current value Isb output from the current detector 12b and the voltage value Vsb output from the voltage detector 13b.
  • the power calculator 14b calculates the power value Psb input to the boost converter circuit 4b based on the current value Isb and the voltage value Vsb.
  • the calculated power value Psb is output to the controller 16.
  • a current detection element 32c is arranged on the DC bus N on the negative electrode side between the negative electrode input terminal 102c and the boost converter circuit 4c.
  • the current detection element 32c detects a current value at the position.
  • a current transformer or a shunt resistor is used for the current detection element 32c.
  • the current detector 12c is realized by an amplifier or a level shift circuit.
  • the current detector 12c detects the output current of the solar cell string 1c, that is, the power supply current.
  • the current detector 12c converts a voltage that is directly proportional to the current detected by the current detection element 32c into a current detection voltage within a low voltage range that can be handled by the power calculator 14c. This current detection voltage corresponds to the current value Isc of the output current of the solar cell string 1c.
  • the current value Isc detected by the current detector 12c is output to the power calculator 14c.
  • 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 the output voltage value of the solar cell string 1c, that is, the power supply voltage.
  • the voltage value detected by the voltage detector 13c is assumed to be Vsc.
  • the voltage value Vsc detected by the voltage detector 13c is output to the controller 16 and the power calculator 14c.
  • the power calculator 14c receives the current value Isc output from the current detector 12c and the voltage value Vsc output from the voltage detector 13c.
  • the power calculator 14c calculates a power value Psc input to the boost converter circuit 4c based on the current value Isc and the voltage value Vsc.
  • the calculated power value Psa is output to the controller 16.
  • One end of the voltage detector 15 is connected to one end of the output relay 6 and one end of the inverter circuit 5 in the system connection line 41 on the U side of the commercial power system 2.
  • the other end of the voltage detector 15 is connected to the other end of the output relay 6 and the other end of the inverter circuit 5 in the system connection line 42 on the W side of the commercial power system.
  • the voltage detector 15 detects a voltage value Vuw that is a voltage between the U side and the W side of the commercial power system 2.
  • the voltage value Vuw is a system voltage that the commercial power system 2 applies to the system interconnection inverter device 3 and is an output voltage of the inverter circuit 5.
  • the voltage value Vuw detected by the voltage detector 15 is output to the controller 16.
  • the controller 16 is used to drive the boost converter circuit 4. Specifically, the gate pulse determined by MPPT (Maximum Power Point Tracking) control, which is the maximum power tracking control that determines the operation mode of the boost converter and tracks the operating points of the plurality of solar cell strings 1 to the maximum power point. Generate directives.
  • MPPT Maximum Power Point Tracking
  • switching element 10a, 10b, 10c shown in FIG. 1 is IGBT (Insulated Gate Bipolar Transistor), transistors other than IGBT may be sufficient.
  • IGBT Insulated Gate Bipolar Transistor
  • MOSFET Metal-Oxide-Semiconductor Field-Effect Transistor
  • boost converter circuits 4a, 4b, 4c are used, but the number of converter circuits may be two or more.
  • the boost converter circuits 4a, 4b, and 4c is shown.
  • the configuration of the converter circuit is not limited to the illustrated example, and includes a step-up / down converter circuit to convert a DC voltage into a desired DC voltage value. Any other power conversion circuit may be used as long as it is a power conversion circuit.
  • Boost converter circuit 4 is provided corresponding to the solar cell string.
  • FIG. 2 is a detailed view of the configuration of the controller 16 shown in FIG.
  • the controller 16 includes an output voltage target value setter 17, voltage comparators 20a, 20b, and 20c, maximum power point determiners 21a, 21b, and 21c, an operation mode determiner 22A, a gate pulse command generator 23a, 23b, 23c.
  • the output voltage target value setting unit 17 sets the control target value of the input side voltage of the inverter circuit 5. This control target value is also the control target value of the output voltage of the boost converter circuit 4.
  • the output voltage target value setter 17 receives the voltage value Vuw output from the voltage detector 15 and outputs the control target value ViiS of the input side voltage of the inverter circuit 5.
  • the output voltage target value setter 17 sets the control target value ViiS as the following equation.
  • ViiS ⁇ 2 ⁇ Vuw + ⁇ (1)
  • the target value of the output voltage in the output voltage target value setter 17 is the voltage value Vuw that is the voltage between the UWs of the commercial power system 2 detected by the voltage detector 15.
  • the present invention is not limited to this.
  • an arbitrary fixed value may be directly set in the output voltage target value setting unit 17 from the outside.
  • a specific example of the fixed value is 380 [V].
  • the system voltage is determined in the range of 202 ⁇ 20 [V] by the Electricity Business Law.
  • 380 [V] is a preferable setting value in consideration of the calculated value by the above equation (1) and the necessary margin so that the input voltage of the inverter circuit 5 is not affected by the voltage fluctuation in this range. Become.
  • the boost ratio of the boost converter circuit 4 can be optimally controlled, and the conversion efficiency of the boost converter circuit 4 can be controlled. Will improve. Generally, when the boost ratio of the boost converter circuit 4 increases, the conversion efficiency decreases. Therefore, if the output voltage target value of boost converter circuit 4 is variable with respect to the system voltage, the boost ratio can be made lower than when the fixed value is set, and conversion efficiency can be improved.
  • the voltage comparator 20a determines the operation mode based on the voltage value Vsa of the solar cell string 1a output from the voltage detector 13a and the control target value ViiS of the inverter circuit 5 output from the output voltage target value setter 17.
  • the boosting operation stop permission signal Csa is output to the device 22A.
  • the voltage comparator 20a compares the voltage value Vsa of the solar cell string 1a with the control target value ViiS of the inverter circuit 5, and determines whether or not to stop the boosting operation as described below.
  • Vsa ⁇ ViiS stop of the boosting operation is permitted. If Vsa ⁇ ViiS, stop of the boosting operation is prohibited.
  • the equal sign in the above comparison may be included in either. That is, contrary to the above, if Vsa> ViiS, the boost operation stop may be permitted, and if Vsa ⁇ ViiS, the boost operation stop may be prohibited.
  • the voltage comparator 20b determines the operation mode based on the voltage value Vsb of the solar cell string 1b output from the voltage detector 13b and the control target value ViiS of the inverter circuit 5 output from the output voltage target value setter 17.
  • the boosting operation stop permission signal Csb is output to the device 22A.
  • the voltage comparator 20b compares the voltage value Vsb of the solar cell string 1b with the control target value ViiS of the inverter circuit 5, and determines whether or not to stop the boosting operation as described below.
  • Vsb ⁇ ViiS stop of the boosting operation is permitted. If Vsb ⁇ ViiS, stop of the boosting operation is prohibited.
  • the equal sign in the above comparison may be included in either. That is, contrary to the above, if Vsb> ViiS, the boost operation stop may be permitted, and if Vsb ⁇ ViiS, the boost operation stop may be prohibited.
  • the voltage comparator 20c is an operation mode determiner.
  • the step-up operation stop permission signal Csc is output to 22A.
  • the voltage comparator 20c compares the voltage value Vsc of the solar cell string 1c with the control target value ViiS of the inverter circuit 5, and determines whether or not to stop the boosting operation as described below.
  • Vsc ⁇ ViiS stop of the boosting operation is permitted. If Vsc ⁇ ViiS, stop of the boosting operation is prohibited.
  • the maximum power point determiner 21a determines that the operating point of the solar cell string 1a is the maximum power point. It is determined whether or not.
  • the maximum power point determiner 21a outputs the determined result as the maximum power point signal Msa to the operation mode determiner 22A.
  • whether or not the operating point is the maximum power point is determined by the following equation.
  • ⁇ Psa / ⁇ Vsa is an index representing how much the power value Psa input to the boost converter circuit 4a changes when the voltage value Vsa of the solar cell string 1a changes.
  • ⁇ Psa / ⁇ Vsa is referred to as “a ratio of power change with respect to voltage change” or “power change rate”.
  • said definition is applied similarly about solar cell string 1b, 1c. That is, ⁇ Psb / ⁇ Vsb and ⁇ Psc / ⁇ Vsc that can be similarly expressed in the solar cell strings 1b and 1c are also referred to as “a ratio of a power change with respect to a voltage change” or “a power change rate”.
  • the maximum power point determiner 21a determines that the operating point is the maximum power point if the above equation (2) is satisfied, and if the above equation (2) is not satisfied, the operating point is not the maximum power point. judge.
  • the output power of the solar cell string 1 does not greatly decrease. Specifically, even if the operating point of the solar cell string 1 deviates from 1 V from the maximum power point, the power is reduced by 1 W or less.
  • the boost converter circuit 4 operates, a loss of several watts due to voltage conversion occurs. Therefore, the loss due to voltage conversion can be reduced by stopping the boost converter circuit 4. Therefore, the determination range shown in the above equation (2) is set in consideration of the loss reduction and the power decrease due to the voltage difference from the maximum power point.
  • the range of said (2) Formula can be set arbitrarily by the characteristic of the boost converter circuit 4 and the solar cell string 1, and is not limited to the range of said (2) Formula. The same applies to the expressions (3) and (4) described later.
  • the maximum power point determiner 21b determines that the operating point of the solar cell string 1b is the maximum power point. It is determined whether or not.
  • the maximum power point determiner 21b outputs the determined result as the maximum power point signal Msb to the operation mode determiner 22A.
  • whether or not the operating point is the maximum power point is determined by the following equation.
  • the maximum power point determiner 21b determines that the operating point is the maximum power point if the above equation (3) is satisfied, and the operating point is not the maximum power point if the above equation (3) is not satisfied. judge.
  • the maximum power point determiner 21c determines that the operating point of the solar cell string 1b is the maximum power point. It is determined whether or not.
  • the maximum power point determiner 21c outputs the determined result as the maximum power point signal Msc to the operation mode determiner 22A.
  • whether or not the operating point is the maximum power point is determined by the following equation.
  • the maximum power point determiner 21c determines that the operating point is the maximum power point if the above equation (4) is satisfied, and the operating point is not the maximum power point if the above equation (4) is not satisfied. judge.
  • the operation mode determiner 22A includes the boost operation stop permission signals Csa, Csb, and Csc output from the voltage comparators 20a, 20b, and 20c, and the maximum output from each of the maximum power point determiners 21a, 21b, and 21c. Based on the power point signals Msa, Msb, and Msc, operation mode commands Qsa, Qsb, and Qsc are output to the gate pulse command generators 23a, 23b, and 23c, respectively.
  • the operation mode determination unit 22A includes boost operation stop permission signals Csa, Csb, and Csc output from the voltage comparators 20a, 20b, and 20c, and the maximum power point output from the maximum power point determination units 21a, 21b, and 21c. Based on the signals Msa, Msb, and Msc, the operation modes of the boost converter circuits 4a, 4b, and 4c are determined.
  • FIG. 3 is a diagram showing combinations of operation conditions and operation modes of the boost converter circuits 4a, 4b, and 4c.
  • the table of FIG. 3 is an example, and is not limited to the description of FIG.
  • the boost converter circuits 4a, 4b, and 4c are described in the order from the left side of the table, but the boost converter circuits 4b, 4a, and 4c may be in this order.
  • boost converter circuit 4 a generic name or any one of the plurality of boost converter circuits 4a, 4b, 4c is represented as “boost converter circuit 4”, and a generic name or any one of the plurality of voltage comparators 20a, 20b, 20c is designated as “voltage”. This will be referred to as “comparator 20”.
  • the operation mode of the boost converter circuit 4 to which the voltage comparator 20 that outputs the prohibited boost operation stop permission signal is connected is the boost operation. It becomes a mode. Specifically, in case 1 in the table of FIG. 3, the boost operation stop permission signal output from the voltage comparator 20b is prohibited, and the boost converter circuit 4b enters the boost operation mode.
  • the operation mode of the boost converter circuit 4 that operates according to the permitted boost operation stop permission signal. Becomes the bypass operation mode, and the operation modes of the other two boost converter circuits 4 become the boost operation mode.
  • the boost operation stop permission signal output from the voltage comparator 20c is permitted, and the boost operation stop permission signal output from the voltage comparators 20a and 20b is prohibited.
  • the boost converter circuit 4c is in the bypass operation mode, and the boost converter circuits 4a and 4b are in the boost operation mode.
  • the operation mode of the boost converter circuit 4 that operates according to the permitted boost operation stop permission signal.
  • the signal indicating that the maximum power point signal is the maximum power point is referred to as “maximum point”
  • the signal indicating that the maximum power point signal is not the maximum power point is indicated as “maximum point”. It is written as “Other than points”.
  • the notation “maximum point / other than maximum point” in the table may be a signal indicating that the maximum power point signal is the maximum power point or a signal indicating that it is not the maximum power point. This means that the maximum power point signal may be arbitrary.
  • description will be made according to the notation of FIG.
  • the operating mode of the boosting converter circuit 4 whose one operating point is the maximum power point is the bypass operating mode.
  • the operation mode of the boost converter circuit 4 whose operating point is not the maximum power point is the boosting operation mode.
  • the boost operation stop permission signal output from the voltage comparators 20b and 20c is enabled, the boost operation stop permission signal output from the voltage comparator 20a is disabled, and the maximum power
  • the maximum power point signal output from the point determiner 21b is the maximum point
  • the maximum power point signal output from the maximum power point determiner 21c is other than the maximum point
  • the boost converter circuit 4b is in the bypass operation mode
  • 4c is the step-up operation mode.
  • the operation mode of the boost converter circuits 4b and 4c is the bypass operation mode, but this may be modified as follows. Specifically, among the boost converter circuits 4 that operate in response to the permitted boost operation stop permission signal, the operation mode of the boost converter circuit 4 having a large Vs output from the voltage detector 13 is set as a bypass operation mode, and the boost is small in Vs. The operation mode of the converter circuit 4 is set as a boost operation mode.
  • the operation mode of the boost converter circuit 4 is the bypass operation mode
  • the input side voltage of the inverter circuit 5 becomes the output voltage of the solar cell string 1 connected to the boost converter circuit 4 operating in the bypass operation mode.
  • the boost converter circuit 4 having a small voltage Vs of the solar cell string 1 is set to the bypass operation mode
  • the boost converter circuit 4 having a high voltage Vs is output from the input to the boost converter circuit 4, that is, the input side voltage of the inverter circuit 5.
  • the step-up operation becomes unnecessary, and the power point cannot be changed.
  • the boost converter circuit 4 having a large voltage Vs when the boost converter circuit 4 having a large voltage Vs is set to the bypass operation mode, the boost converter circuit 4 having a low voltage Vs has an output that is larger than an input to the boost converter circuit 4, that is, an input side voltage of the inverter circuit 5. Therefore, the boosting operation by the boosting converter circuit 4 is required, and the operating point can be changed. For this reason, the operation mode of the boost converter circuit 4 in which the voltage Vs of the solar cell string 1 is large is set as a bypass operation mode. A specific example will be described below.
  • Vs output from the voltage detector 13 is
  • the operation mode of the large boost converter circuit is a bypass operation mode
  • the operation mode of the boost converter circuit having a small Vs is a boost operation mode.
  • the operation mode of the boost converter circuit 4 that operates according to the permitted boost operation stop permission signal is as follows.
  • the operating point of the solar cell string 1 connected to the boosting converter circuit 4 operated by the permission boosting operation stop permission signal includes the case of the maximum point and the case of not being the maximum point
  • the operating point is the maximum.
  • the operation mode of the boost converter circuit 4 as a point is the bypass operation mode.
  • the operation mode of the boost converter circuit 4 whose operating point is not the maximum is the boost mode.
  • the boost operation stop permission signal output from each of the voltage comparators 20a, 20b, and 20c is permitted.
  • the maximum power point signal output from the maximum power point determiners 21a, 21b, and 21c is the maximum point.
  • the boost converter circuits 4a, 4b, 4c, that is, all the boost converter circuits 4 are in the bypass operation mode.
  • boost operation stop permission signal output from each of the voltage comparators 20a, 20b, and 20c is permitted.
  • the maximum power point signal output from the maximum power point determiners 21a and 21b is the maximum point, and the maximum power point signal output from the maximum power point determiner 21c is other than the maximum point.
  • boost converter circuits 4a and 4b are in the bypass operation mode, and boost converter circuit 4c is in the boost operation mode.
  • Vs output from the voltage detector 13 is one.
  • the operation mode of the largest boost converter circuit is set as a bypass operation mode, and the operation mode of another boost converter circuit having a small Vs is set as a boost operation mode. A specific example will be described below.
  • the boost operation stop permission signal output from the voltage comparators 20a, 20b, and 20c is permitted.
  • the maximum power point signals output from the maximum power point determiners 21a, 21b, and 21c are other than the maximum point.
  • the voltage Vsa of the solar cell string 1a output from the voltage detector 13a is 350V
  • the voltage Vsb of the solar cell string 1b output from the voltage detector 13b is 340V
  • the solar cell string output from the voltage detector 13c is assumed to be 330V.
  • Vsa> Vsb> Vsc the operation mode of the boost converter circuit 4a is the bypass operation mode
  • the operation mode of the boost converter circuits 4b and 4c is the boost operation mode.
  • the gate pulse command generator 23a receives the operation mode command Qsa output from the operation mode determination unit 22A.
  • the gate pulse command generator 23a outputs a gate pulse command Gsa for operating the boost converter circuit 4a to the gate pulse generator 18a based on the received operation mode command Qsa.
  • the gate pulse command generator 23a performs a gate such that the operation point of the solar cell string 1a connected to the step-up converter circuit 4a is the maximum power point.
  • the pulse command Gsa is output to the gate pulse generator 18a.
  • the gate pulse command generator 23a outputs a gate pulse command Gsa that stops the operation of the boost converter circuit 4a when the operation mode included in the received operation mode command Qsa is the bypass operation mode. Output to.
  • the gate pulse command generator 23b receives the operation mode command Qsb output from the operation mode determination unit 22A.
  • the gate pulse command generator 23b outputs a gate pulse command Gsb for operating the boost converter circuit 4b to the gate pulse generator 18b based on the received operation mode command Qsb.
  • the gate pulse command generator 23b performs a gate such that the operation point of the solar cell string 1b connected to the step-up converter circuit 4b is the maximum power point.
  • the pulse command Gsb is output to the gate pulse generator 18b.
  • the gate pulse command generator 23b sends a gate pulse command Gsb to stop the operation of the boost converter circuit 4b when the operation mode included in the received operation mode command Qsb is the bypass operation mode. Output to.
  • the gate pulse command generator 23c receives the operation mode command Qsc output from the operation mode determination unit 22A. Based on the received operation mode command Qsc, the gate pulse command generator 23c outputs a gate pulse command Gsc for operating the boost converter circuit 4c to the gate pulse generator 18c. When the operation mode included in the received operation mode command Qsc is the step-up operation mode, the gate pulse command generator 23c performs gate operation such that the operation point of the solar cell string 1c connected to the step-up converter circuit 4c is the maximum power point. The pulse command Gsc is output to the gate pulse generator 18c.
  • the gate pulse command generator 23c outputs a gate pulse command Gsc that stops the operation of the boost converter circuit 4c when the operation mode included in the received operation mode command Qsc is the bypass operation mode. Output to.
  • FIG. 4 is a flowchart for explaining the operation of the controller 16 of the grid interconnection inverter device 3 according to the first embodiment.
  • the output voltage target value setting unit 17 sets the control target value ViiS of the inverter circuit 5. At this time, ViiS is calculated by the above equation (1).
  • the operation mode of the boost converter circuit 4 permitted to stop the boost operation is the bypass operation mode.
  • the case where the number of boost converter circuits 4 permitted to stop the boost operation is not plural is the case where the number of boost converter circuits 4 permitted to stop the boost operation is one and the case where the boost operation is stopped.
  • the permitted operation mode of the boost converter circuit 4 becomes the bypass operation mode, and the remaining operation modes of the boost converter circuit 4 become the boost operation mode. .
  • Vsa, Vsb, Vsc and power values Psa, Psb, Psc measured in S201 are as follows.
  • Vsa 330 [V]
  • Vsb 320 [V]
  • Vsc 280 [V]
  • Psa 1000 [W]
  • Psb 900 [W]
  • Psc 800 [W]
  • the voltage value Vuw measured in S202 is set to the following value.
  • Vuw 200 [V]
  • ⁇ Psa / ⁇ Vsa, ⁇ Psb / ⁇ Vsb, and ⁇ Psc / ⁇ Vsc used in S210, S212, and S214 use the following values.
  • ⁇ Psa / ⁇ Vsa 0.9 [W / V]
  • ⁇ Psb / ⁇ Vsb 1.2 [W / V]
  • ⁇ Psc / ⁇ Vsc 0.5 [W / V]
  • Vsc (280 V) ⁇ Viis (317.8 V) is established, and the stop of the boost operation of the boost converter circuit 4 c is prohibited.
  • the boost converter circuit 4a is allowed to stop the boost operation, and the solar cell string 1a operates at the maximum power point.
  • Boost converter circuit 4b is allowed to stop the boost operation, and solar cell string 1b is operating at a point other than the maximum power point.
  • the boost converter circuit 4c is prohibited from stopping the boost operation, and the solar cell string 1c is operating at the maximum power point.
  • the boost converter circuits 4a and 4b are permitted to stop the boost operation, and the operating point of the solar cell string 1a is the maximum power point. Therefore, the operation mode of the boost converter circuit 4a is the bypass operation mode.
  • the operation mode of converter circuits 4b and 4c is a boost operation mode.
  • the controller 16 determines the operation mode of the boost converter circuits 4a, 4b, and 4c by the controller 16, and outputs a gate pulse corresponding to the operation mode. It is a configuration. With such a configuration, the operation mode of the plurality of boost converter circuits 4 can be set to the bypass operation mode, and the conversion efficiency of the boost converter circuit 4 can be improved.
  • the conventional grid-connected inverter device When a plurality of solar cell strings are connected to the grid interconnection inverter device, a voltage difference is generated due to the installation environment even if the number of connections is the same. For this reason, the conventional grid-connected inverter device has a problem that a plurality of boost converter circuits cannot be operated in the bypass operation mode, and the conversion efficiency of the boost converter circuit is lowered.
  • the plurality of boost converter circuits can be operated in the bypass operation mode.
  • the conversion efficiency of the boost converter circuit can be improved.
  • the operation of the controller 16 is different between the grid interconnection inverter device according to the second embodiment and the grid interconnection inverter device according to the first embodiment. Therefore, hereinafter, the operation of the controller 16 different from that of the first embodiment will be mainly described.
  • the structure of the grid connection inverter apparatus 3 which concerns on Embodiment 2 is the same as that of the grid connection inverter apparatus 3 which concerns on Embodiment 1, or description is abbreviate
  • FIG. 5 is a detailed diagram of the configuration of the controller 16 in the second embodiment.
  • the controller 16 includes an output voltage target value setter 17, a voltage comparator 30, power change detectors 31a, 31b, 31c, an operation mode determiner 22B, gate pulse command generators 23a, 23b, 23c, Is provided. Since the output voltage target value setting unit 17 and the gate pulse command generators 23a, 23b, and 23c are the same as those in the first embodiment, the description thereof is omitted here.
  • the voltage comparator 30 includes the voltage values Vsa, Vsb, Vsc of the solar cell strings 1a, 1b, 1c output from the voltage detectors 13a, 13b, 13c, and the inverter output from the output voltage target value setting unit 17. Based on the control target value ViiS of the circuit 5, the step-up operation stop permission signal Cs is output to the operation mode determination unit 22B.
  • the voltage comparator 30 compares the respective voltage values Vsa, Vsb, Vsc of the solar cell strings 1a, 1b, 1c with the control target value ViiS of the inverter circuit 5, and permits or prohibits the boost operation stop as described below. judge.
  • Vsa ⁇ ViiS stop of the boost operation of the boost converter circuit 4a is permitted. If Vsa ⁇ ViiS, stop of the boosting operation of the boost converter circuit 4a is prohibited. If Vsb ⁇ Viis, stop of the boosting operation of the boost converter circuit 4b is permitted. If Vsb ⁇ ViiS, stop of the boost operation of the boost converter circuit 4b is prohibited. If Vsc ⁇ ViiS, stop of the boosting operation of the boost converter circuit 4c is permitted. If Vsc ⁇ ViiS, the boost operation of the boost converter circuit 4c is prohibited from being stopped.
  • the voltage comparator 30 further detects the largest voltage among the voltage values Vsa, Vsb, Vsc of the solar cell strings 1a, 1b, 1c, and sets it as Vsmax.
  • the boost converter circuit 4 to which Vsmax, Vs, is input is allowed to stop the boost operation.
  • the boost operation of the boost converter circuit 4 is permitted to be stopped.
  • the boost operation of the boost converter circuit 4 is prohibited.
  • the voltage comparator 30 determines whether the boosting operation of each of the boost converter circuits 4a, 4b, 4c is permitted or prohibited, and generates a boosting operation stop permission signal Cs including such information as an operation mode determination unit 22B. Output to.
  • the determination value of the difference between Vsmax and Vs has been described as 1 [V], but is not limited to this value.
  • the determination value can be obtained by comparing the reduced amount of voltage conversion loss caused by stopping the boost converter circuit 4 and the reduced amount of power caused by the voltage difference from the maximum power point. The important point is that the power difference due to the voltage difference from the maximum power point should be a voltage difference that can be made smaller than the reduction in voltage conversion loss caused by stopping the boost converter circuit 4.
  • the power change detector 31a is based on the voltage value Vsa of the solar cell string 1a output from the voltage detector 13a and the power value Psa calculated by the power calculator 14a, and the power change rate R_Psa at the operating point of the solar cell string 1a. Is calculated and output to the operation mode determiner 22B.
  • the power change rate R_Psa As the power change rate R_Psa, ⁇ Psa / ⁇ Vsa described in the first embodiment can be used.
  • the power change detector 31b is based on the voltage value Vsb of the solar cell string 1b output from the voltage detector 13b and the power value Psb calculated by the power calculator 14b, and the power change rate R_Psb at the operating point of the solar cell string 1b. Is calculated and output to the operation mode determiner 22B.
  • the power change rate R_Psb ⁇ Psb / ⁇ Vsb described in the first embodiment can be used.
  • the power change detector 31c is based on the voltage value Vsc of the solar cell string 1c output from the voltage detector 13c and the power value Psc calculated by the power calculator 14c, and the power change rate R_Psc at the operating point of the solar cell string 1c. Is calculated and output to the operation mode determiner 22B.
  • the power change rate R_Psc ⁇ Psc / ⁇ Vsc described in the first embodiment can be used.
  • the operation mode determiner 22B is based on the boost operation stop permission signal Cs output from the voltage comparator 30 and the power change rates R_Psa, R_Psb, R_Psc output from the power change detectors 31a, 31b, 31c. Operation mode commands Qsa, Qsb, Qsc are output to the pulse command generators 23a, 23b, 23c, respectively.
  • the operation mode determination unit 22B is based on the boost operation stop permission signal Cs output from the voltage comparator 30 and the power change rates R_Psa, R_Psb, and R_Psc output from the power change detectors 31a, 31b, and 31c. Thus, the operation mode of boost converter circuits 4a, 4b and 4c is determined.
  • FIG. 6 is a diagram showing combinations of operation conditions and operation modes in boost converter circuits 4a, 4b, and 4c.
  • FIG. 7 is a diagram showing the relationship between the characteristics of the solar cell string and the power change rate.
  • the table in FIG. 6 is an example and is not limited to the description in FIG.
  • the boost converter circuits 4a, 4b, and 4c are described in the order from the left side of the table, but the boost converter circuits 4b, 4a, and 4c may be in this order.
  • the boosting operation stop permission signal and the code notation of the power change rate are appropriately omitted.
  • a generic name or any one of the plurality of boost converter circuits 4a, 4b, 4c is expressed as “boost converter circuit 4”
  • a generic name or any one of the plurality of power change detectors 31a, 31b, 31c is “ This is expressed as “electric power change detector 31”.
  • the operation mode of the boost converter circuit 4c becomes the bypass operation mode.
  • the operation mode of converter circuits 4a and 4b is a boost operation mode. Specifically, in case 2 in the table of FIG. 6, the boost operation stop permission signal output from the voltage comparator 30 is prohibited for the boost converter circuits 4a and 4b, and permitted for the boost converter circuit 4c.
  • the boost converter circuits 4a and 4b are in the boost operation mode, and the boost converter circuit 4c is in the bypass operation mode.
  • the operation mode is determined by the power change rate detected by the power change detectors 31a, 31b, 31c. At this time, the polarity of the power change rate of the boost converter circuit 4 for which the boost operation stop permission signal is permitted is compared.
  • the operation mode of the two boost converter circuits 4 is set to the bypass operation mode.
  • the operation mode of the boost converter circuit in which the power change rate is negative is set as the bypass operation mode, and the operation mode of the boost converter circuit in which the power change rate is positive.
  • the step-up operation mode is set. The reason for this will be described with reference to FIG.
  • the characteristic curve K1 of the solar cell string refers to the characteristic curve K1 of the solar cell string.
  • the current operating point is shown on the characteristic curve K1.
  • the rate of power change is positive.
  • the maximum power point is on the higher voltage side than the current operating point, as is apparent from the illustrated waveform.
  • the characteristic curve K2 of another solar cell string is referred to.
  • the power change rate is negative.
  • the maximum power point is on the lower voltage side than the current operating point.
  • the maximum power point can be tracked by setting one to the boost operation mode and the other to the bypass operation mode.
  • the boost converter circuit 4 connected to the solar cell string 1 having a large maximum power point voltage is set to the bypass operation mode, and the solar cell string 1 having a small maximum power point voltage is set.
  • the operation mode of the boost converter circuit 4 connected to is defined as a boost operation mode.
  • the boost converter circuit 4 connected to the solar cell string 1 having a positive power change rate is set to the bypass operation mode, and the solar power having a negative power change rate is used.
  • the operation mode of the boost converter circuit 4 connected to the battery string 1 is defined as a boost operation mode.
  • the power change rate related to the boost converter circuit 4b is positive, and the power change rate related to the boost converter circuit 4c is negative and has a different polarity. Therefore, the operation mode of the boost converter circuit 4b connected to the solar cell string 1 having a positive power change rate is the bypass operation mode, and the boost converter circuit 4c connected to the solar cell string 1 having a negative power change rate. This operation mode is a step-up operation mode.
  • Case 5 is the reverse of Case 4.
  • the power change rate related to the boost converter circuit 4b is negative
  • the power change rate related to the boost converter circuit 4c is positive and has a different polarity. Therefore, the operation mode of the boost converter circuit 4b connected to the solar cell string 1 having a negative power change rate is the boost operation mode, and the boost converter circuit 4c connected to the solar cell string 1 having a positive power change rate. This operation mode is a bypass operation mode.
  • the operation mode can be determined as in the case of two. This will be specifically described below.
  • the operation modes of the boost converter circuits 4a and 4b are the bypass operation mode and the operation mode of the boost converter circuit 4c. Is a step-up operation mode.
  • the operation modes of the boost converter circuits 4a and 4c are the bypass operation mode and the operation mode of the boost converter circuit 4b. Is a step-up operation mode.
  • the operation mode of the boost converter circuit 4a is the bypass operation mode, and the operation modes of the boost converter circuits 4b and 4c. Is a step-up operation mode.
  • the operation modes of the boost converter circuits 4b and 4c are the bypass operation mode and the operation mode of the boost converter circuit 4a. Is a step-up operation mode.
  • the operation mode of the boost converter circuit 4b is the bypass operation mode, and the operation mode of the boost converter circuits 4a and 4c. Is a step-up operation mode.
  • the operation mode of the boost converter circuit 4c is the bypass operation mode, and the boost converter circuits 4a and 4b
  • the operation mode is a boost operation mode.
  • the operation mode of the boost converter circuits 4a, 4b, and 4c is the bypass operation mode.
  • FIG. 8 is a flowchart for explaining the operation of the controller 16 of the grid interconnection inverter device 3 according to the second embodiment.
  • the output voltage target value setting unit 17 sets the control target value ViiS of the inverter circuit 5. At this time, ViiS is calculated by the above equation (1).
  • the voltage comparator 30 detects the largest voltage value Vsmax among the voltage values Vsa, Vsb, and Vsc detected by the voltage detectors 13a, 13b, and 13c.
  • the voltage value Vsa detected by the voltage detector 13 a is compared with the control target value ViiS set by the output voltage target value setter 17. Further, the voltage comparator 30 compares the voltage value Vsmax detected in S304 with the voltage value Vsa detected by the voltage detector 13a.
  • the voltage value Vsb detected by the voltage detector 13 b is compared with the control target value ViiS set by the output voltage target value setting unit 17. Further, the voltage comparator 30 compares the voltage value Vsmax detected in S304 with the voltage value Vsb detected by the voltage detector 13b.
  • power change rates R_Psa, R_Psb, and R_Psc are calculated based on the voltage value Vsa detected by the voltage detector 13a and the power value Psa calculated by the power calculator 14a.
  • the operation mode of the boost converter circuit 4 permitted to stop the boost operation is set to the bypass operation mode.
  • the case where the number of boost converter circuits 4 permitted to stop the boost operation is not plural is the case where the number of boost converter circuits 4 permitted to stop the boost operation is one and the case where the boost operation is stopped.
  • the permitted operation mode of the boost converter circuit 4 becomes the bypass operation mode, and the remaining operation modes of the boost converter circuit 4 become the boost operation mode. .
  • Vsa, Vsb, Vsc and power values Psa, Psb, Psc measured in S301 are as follows.
  • Vsa 320 [V]
  • Vsb 319 [V]
  • Vsc 280 [V]
  • Psa 1000 [W]
  • Psb 900 [W]
  • Psc 800 [W]
  • the voltage value Vuw measured in S302 is set to the following value.
  • Vuw 200 [V]
  • the power change rates R_Psa, R_Psb, and R_Psc used in S311 use the following values.
  • the largest voltage Vsmax is a voltage value Vsa, which is 320 [V].
  • Vsmax (320 [V]) ⁇ Vsa (320 [V]) 0
  • ⁇ 1 [V] are satisfied, and the boost converter circuit 4a is boosted. Stopping operation is permitted.
  • Boost converter circuits 4a and 4b are allowed to stop the boost operation, but boost converter circuit 4c is prohibited from stopping the boost operation. Since the stop of the boost operation of the two boost converter circuits 4 called the boost converter circuits 4a and 4b is permitted, the power change rates R_Psa and R_Psb are confirmed. Here, since the power change rate R_Psa (0.9 [W / V]) ⁇ 0 and R_Psb ( ⁇ 1.2 [W / V]) ⁇ 0, the operation mode of the boost converter circuit 4a is the bypass operation mode. The operation mode of boost converter circuits 4b and 4c is the boost operation mode.
  • the controller 16 determines the operation mode of the boost converter circuits 4a, 4b, and 4c and outputs a gate pulse corresponding to the operation mode. It is a configuration. With such a configuration, the operation mode of the plurality of boost converter circuits 4 can be set to the bypass operation mode, and the conversion efficiency of the boost converter circuit 4 can be improved.
  • the first embodiment is a method using the maximum power point of the solar cell string 1, while the second embodiment uses a power change rate that is a ratio of the power change to the voltage change of the solar cell string 1. It is a technique to do. Since the maximum power point is affected by the material of the solar battery cells constituting the solar battery string 1, the determination value needs to be changed if the material of the solar battery cells is different. On the other hand, in the case of the power change rate, since it is hardly affected by the material of the solar battery cell, it is not necessary to change the determination value even if the material of the solar battery cell is different. That is, if the method of Embodiment 2 is used, the operation mode of boost converter circuit 4 can be determined without depending on the material of the solar cell.
  • the conventional grid-connected inverter device When a plurality of solar cell strings are connected to the grid-connected inverter, a voltage difference occurs due to the installation environment even if the number of connections is the same. For this reason, the conventional grid-connected inverter device has a problem that a plurality of boost converter circuits cannot be operated in the bypass operation mode, and the conversion efficiency of the boost converter circuit is lowered.
  • the grid interconnection inverter device 3 since the plurality of boost converter circuits can be operated in the bypass operation mode even if the installation environment of the plurality of solar cell strings is different, The conversion efficiency of the boost converter circuit can be improved.
  • 1a, 1b, 1c solar cell string 2 commercial power system, 3 grid interconnection inverter device, 4a, 4b, 4c boost converter circuit, 5 inverter circuit, 6 output relay, 7a, 7b, 7c, 8 smoothing capacitor, 9a , 9b, 9c reactor, 10a, 10b, 10c switching element, 11a, 11b, 11c diode, 12a, 12b, 12c current detector, 13a, 13b, 13c, 15 voltage detector, 14a, 14b, 14c power calculator, 16 controller, 17 output voltage target value setter, 18a, 18b, 18c gate pulse generator, 20a, 20b, 20c, 30 voltage comparator, 21a, 21b, 21c maximum power point determiner, 22A, 22B operation mode determination 23a, 23b, 23c gate pulse command Generator, 31a, 31b, 31c Power change detector, 32a, 32b, 32c Current detection element, 100 Solar power generation system, 101a, 101b, 101c Positive input terminal, 102a, 102b, 102

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electromagnetism (AREA)
  • Sustainable Energy (AREA)
  • Sustainable Development (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Inverter Devices (AREA)
  • Dc-Dc Converters (AREA)
  • Control Of Electrical Variables (AREA)

Abstract

L'invention concerne un appareil d'onduleur d'interconnexion de systèmes 3 comprenant : des circuits de convertisseur élévateur 4 dans lesquels est entrée une énergie produite par des séries de batteries solaires ; un circuit d'onduleur 5 qui convertit en tension alternative la tension continue produite par chacun des circuits de convertisseur élévateur 4 ; des détecteurs de tension 13 qui détectent chacun, pour chaque série de batteries solaires 1, une tension d'alimentation qui est une tension de sortie de la série de batteries solaires 1 ; des détecteurs de courant 12 qui détectent chacun, pour chaque série de batteries solaires 1, un courant d'alimentation qui est un courant de sortie de la série de batteries solaires 1 ; un détecteur de tension 15 qui détecte une tension de système appliquée au circuit d'onduleur 5 par un système d'alimentation industriel 2 ; et une unité de commande 16 qui détermine s'il faut autoriser/interdire l'arrêt de l'opération d'élévation des circuits du convertisseur élévateur 4, à l'aide de la tension d'alimentation, du courant d'alimentation et de la tension du système.
PCT/JP2016/083110 2016-11-08 2016-11-08 Appareil d'onduleur d'interconnexion de systèmes WO2018087813A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/JP2016/083110 WO2018087813A1 (fr) 2016-11-08 2016-11-08 Appareil d'onduleur d'interconnexion de systèmes
JP2017518563A JP6195690B1 (ja) 2016-11-08 2016-11-08 系統連系インバータ装置

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2016/083110 WO2018087813A1 (fr) 2016-11-08 2016-11-08 Appareil d'onduleur d'interconnexion de systèmes

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US14/740,725 Continuation US9673046B2 (en) 2012-12-17 2015-06-16 Gallium nitride substrate and manufacturing method of nitride semiconductor crystal

Publications (1)

Publication Number Publication Date
WO2018087813A1 true WO2018087813A1 (fr) 2018-05-17

Family

ID=59854924

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2016/083110 WO2018087813A1 (fr) 2016-11-08 2016-11-08 Appareil d'onduleur d'interconnexion de systèmes

Country Status (2)

Country Link
JP (1) JP6195690B1 (fr)
WO (1) WO2018087813A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111313471A (zh) * 2020-03-30 2020-06-19 科华恒盛股份有限公司 逆变器升压旁路切换方法及光伏发电系统
KR20220026673A (ko) * 2020-08-26 2022-03-07 한국항공우주연구원 최대 전력점 추종 제어 알고리즘을 구비한 전력 시스템

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000112545A (ja) * 1998-09-30 2000-04-21 Daihen Corp 太陽光発電システム
JP2016082751A (ja) * 2014-10-17 2016-05-16 住友電気工業株式会社 変換装置

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000112545A (ja) * 1998-09-30 2000-04-21 Daihen Corp 太陽光発電システム
JP2016082751A (ja) * 2014-10-17 2016-05-16 住友電気工業株式会社 変換装置

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111313471A (zh) * 2020-03-30 2020-06-19 科华恒盛股份有限公司 逆变器升压旁路切换方法及光伏发电系统
CN111313471B (zh) * 2020-03-30 2021-10-01 科华恒盛股份有限公司 逆变器升压旁路切换方法及光伏发电系统
KR20220026673A (ko) * 2020-08-26 2022-03-07 한국항공우주연구원 최대 전력점 추종 제어 알고리즘을 구비한 전력 시스템
KR102374918B1 (ko) * 2020-08-26 2022-03-16 한국항공우주연구원 최대 전력점 추종 제어 알고리즘을 구비한 전력 시스템

Also Published As

Publication number Publication date
JP6195690B1 (ja) 2017-09-13
JPWO2018087813A1 (ja) 2018-11-15

Similar Documents

Publication Publication Date Title
US6765315B2 (en) Bi-directional regulator/converter with buck/boost by fuzzy logic control
US8531855B2 (en) Power conversion apparatus
US8754549B2 (en) Power conversion device
US10742128B2 (en) Parallel power supply device
US20100177540A1 (en) Power conversion apparatus
JP2005235082A (ja) 最大電力追尾制御方法及び電力変換装置
US10044281B2 (en) Bidirectional insulated DC/DC converter and smart network using the same
US10090691B2 (en) Power generation system of renewable-energy-based electric power generator and DC power source combiner provided with reverse current prevention device capable of preventing power loss in power generation system
US20190149044A1 (en) Dc-dc converter
US20200235655A1 (en) Power supply apparatus
WO2017212572A1 (fr) Dispositif onduleur connecté au réseau électrique
JP6195690B1 (ja) 系統連系インバータ装置
JP6400238B2 (ja) 系統連系インバータ装置
JP2021027749A (ja) 充放電制御装置およびそれを備えたバッテリ並びに直流給電システム
US11233420B2 (en) Uninterruptible power supply apparatus
EP4297232A1 (fr) Système d'énergie, et procédé de commande de charge et de décharge
EP3984123A1 (fr) Systèmes et procédés d'équilibrage de tension pour convertisseurs multiniveaux
WO2018061424A1 (fr) Système de conversion de puissance et dispositif de conversion de puissance
JP2018088073A (ja) 太陽光発電制御装置
JPWO2007108427A1 (ja) 電圧調整装置
CN116094358A (zh) 一种反激式微逆临界断续模式模拟控制方法
US20150295409A1 (en) Micro-grid operation system with smart energy management
CN110601256B (zh) 一种功率流动控制方法
US11264907B2 (en) Multi-phase converter including controller to calculate estimated value
KR20060091450A (ko) 태양전지와 리튬이차전지를 위한 충전제어회로

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 2017518563

Country of ref document: JP

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16921133

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16921133

Country of ref document: EP

Kind code of ref document: A1