WO2014171176A1 - Switching device, failure detection device, solar power system, and switching method - Google Patents

Switching device, failure detection device, solar power system, and switching method Download PDF

Info

Publication number
WO2014171176A1
WO2014171176A1 PCT/JP2014/053893 JP2014053893W WO2014171176A1 WO 2014171176 A1 WO2014171176 A1 WO 2014171176A1 JP 2014053893 W JP2014053893 W JP 2014053893W WO 2014171176 A1 WO2014171176 A1 WO 2014171176A1
Authority
WO
WIPO (PCT)
Prior art keywords
solar cell
mosfets
source
switching device
diode
Prior art date
Application number
PCT/JP2014/053893
Other languages
French (fr)
Japanese (ja)
Inventor
吉富政宣
石井隆文
Original Assignee
Ｊｘ日鉱日石エネルギー株式会社
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 Ｊｘ日鉱日石エネルギー株式会社 filed Critical Ｊｘ日鉱日石エネルギー株式会社
Publication of WO2014171176A1 publication Critical patent/WO2014171176A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/02016—Circuit arrangements of general character for the devices
    • H01L31/02019—Circuit arrangements of general character for the devices for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/02021—Circuit arrangements of general character for the devices for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
    • H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors
    • H03K17/6871—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors the output circuit comprising more than one controlled field-effect transistor
    • H03K17/6874—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors the output circuit comprising more than one controlled field-effect transistor in a symmetrical configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • 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

  • JP2013-087730 application number filed in Japan on April 18, 2013.
  • the contents described in JP2013-087730 are incorporated into the present application.
  • the present invention relates to a switching device, a failure detection device, a solar power generation system, and a switching method, for example, a switching device and a method for disconnecting a solar cell in the solar power generation system.
  • a photovoltaic power generation system that generates power using sunlight
  • a plurality of solar cell modules are connected in series and in parallel, and the generated power that has become a large voltage and a large current is a power conditioner or the like.
  • a power conditioner or the like are supplied to a commercial power system and the like.
  • a plurality of solar cell modules are connected in series to form a solar cell string.
  • a plurality of solar cell strings are connected in parallel to form a solar cell array.
  • a ground fault may occur where the electric circuit comes into contact with the outside in an unintended manner. For example, when a person or an object touches a poorly insulated part, or when a poorly insulated part comes into contact with a metal mount or the like.
  • problems such as failure of a bypass diode built into the solar cell module and poor conduction between solar cells may occur. Therefore, an apparatus for detecting such a fault such as a ground fault is arranged in the solar power generation system (see, for example, Patent Document 1).
  • the solar cell array diagnosis method disclosed in Japanese Patent Application Laid-Open No. 2011-066632 it is effective to separate the positive cell string to be diagnosed from other solar cell strings.
  • the ground fault detection device disclosed in Japanese Patent Application Laid-Open No. 2011-002417 it is necessary that the solar cell is insulated from the ground, and when the inverter is a non-insulated system, the solar cell string to be diagnosed is It is effective to disconnect from the inverter.
  • FIG. 20 is a conceptual diagram illustrating a part of the configuration of the solar power generation system.
  • a plurality of solar cell strings 502 are connected in parallel to form a solar cell array 501.
  • the solar cell array 501 is connected to the load device 510 via the circuit breaker 506 and supplied with electric power.
  • Each solar cell string 502 is connected to a positive electrode (+) side and a negative electrode ( ⁇ ) side, respectively, with a switch 503 such as a circuit breaker or a disconnector, and a plurality of solar cell strings 502 are connected in parallel via the bipolar electrode switch 503. Connected.
  • each solar cell string 502 is provided with a backflow preventing diode 504 so that a leakage current from the load device 510 or another solar cell string 502 does not flow to the solar cell string 502 side.
  • the switch 503, the diode 504, and the circuit breaker 506 on the positive electrode side of the solar cell string 502 are disposed in the connection box 508.
  • the switch 503 and the circuit breaker 506 on the negative electrode side of the solar cell string 502 are disposed in the connection box 509.
  • the connection box 508 and the connection box 509 are often the same casing.
  • the solar cell string 502 electrically disconnected from the photovoltaic power generation system by the switch 503 is connected to a failure detection device (not shown). After the detection operation by the failure detection device, it is necessary to automatically return the solar cell string 502 to be detected to the solar power generation system unless there is an abnormality. Therefore, a switch device that can be automatically controlled is required as the switch 503. .
  • a switch device that can be automatically controlled is required as the switch 503.
  • a mechanical switch has been used as the switch 503.
  • the mechanical switch has a problem that an arc is generated when the circuit is opened (OFF) in a state where a current flows from the solar cell string 502.
  • a semiconductor switch instead of a mechanical switch is being studied.
  • a semiconductor switch power required for opening and closing operations can be reduced, and durability against repeated operations can be improved.
  • a MOSFET Metal Oxide Semiconductor Field Effect Transistor
  • a parasitic diode exists in parallel. Therefore, even if the circuit is interrupted by the transistor function, a current flows through the parasitic diode in one direction. Therefore, it arrange
  • the reverse resistance of the diode 504 for preventing backflow varies depending on the voltage, and generally becomes low resistance at low voltage and high resistance at high voltage. Therefore, the backflow prevention diode 504 can sufficiently cut off a reverse current that is large enough to damage the solar cell string when the system is generating power. No blocking effect can be expected.
  • the present invention has an object to provide an apparatus and a method that can overcome the above-described problems and can electrically disconnect a solar cell from a photovoltaic power generation system while reducing the power required for opening and closing operations. .
  • the switching device of one embodiment of the present invention includes: A switching device that performs an opening operation that electrically connects a solar cell and a load device that consumes or converts power generated by the solar cell and a closing operation that is connected by wiring,
  • the wiring is opened and closed using a first semiconductor element that is arranged in the middle of the wiring and has a transistor portion that performs switching between the source and drain and a diode portion that flows current in a predetermined direction between the source and drain of the transistor portion.
  • An opening and closing part A blocking unit using the second semiconductor element, which is arranged in series with the first semiconductor element in the middle of the wiring and blocks a current flowing through the diode unit included in the first semiconductor element; It is provided with.
  • the failure detection device for a solar cell includes: A switching device as described above; A detection unit for detecting a failure of the solar cell electrically disconnected by the switching device; It is provided with.
  • the photovoltaic power generation system of one embodiment of the present invention includes: A solar cell array in which a plurality of solar cell strings in which a plurality of solar cell modules are connected in series are connected in parallel; A load device that is connected to a plurality of solar cell strings by wiring and that consumes or converts the power generated by the plurality of solar cell strings; A transistor unit that is arranged in the middle of at least one of the positive electrode side and the negative electrode side of the wiring for each solar cell string, and that conducts current in a predetermined direction between the source and drain of the transistor unit and a transistor unit that performs switching between the source and drain An opening / closing part that opens and closes at least one of the wirings using a first semiconductor element having: A second semiconductor element that is arranged in series with the first semiconductor element in the middle of at least one of the above-described wirings for each solar cell string and that cuts off a current flowing through a diode portion included in the first semiconductor element is used. A blocking section; It is provided with.
  • the switching method of one embodiment of the present invention includes: A switching method for performing an open operation for electrically disconnecting a solar cell and a load device that consumes or converts the power generated by the solar cell connected by wiring and a close operation for connection, An opening operation of the wiring is performed using a first semiconductor element that is arranged in the middle of the wiring and has a transistor portion that performs switching between the source and the drain and a diode portion that flows current in a predetermined direction between the source and the drain of the transistor portion. Done Using the second semiconductor element arranged in series with the first semiconductor element in the middle of the wiring, the first semiconductor element flows in the diode portion of the first semiconductor element in a state where the wiring is controlled to be opened. The current is cut off.
  • the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation and maintaining the durability.
  • FIG. 1 is a configuration diagram showing a configuration of a photovoltaic power generation system in Embodiment 1.
  • FIG. 3 is a diagram illustrating an example of an internal configuration of a switching device according to Embodiment 1.
  • FIG. 3 is a cross-sectional view showing an example of a MOSFET in the first embodiment.
  • FIG. It is a figure which shows an example of the solar cell array and switching apparatus which become a comparative example of Embodiment 1.
  • FIG. It is a figure which shows another example of the solar cell array and switching device which become a comparative example of Embodiment 1.
  • FIG. It is a figure which shows another example of the solar cell array and switching device which become a comparative example of Embodiment 1.
  • FIG. 1 is a configuration diagram showing a configuration of a photovoltaic power generation system in Embodiment 1.
  • FIG. 3 is a diagram illustrating an example of an internal configuration of a switching device according to Embodiment 1.
  • FIG. 3 is a cross
  • FIG. 6 is a diagram illustrating an example of an internal configuration of a switching device according to Embodiment 2.
  • FIG. 10 is an example of an external view of a MOSFET in a second embodiment.
  • FIG. 10 is a diagram illustrating an example of an internal configuration of a switching device according to a third embodiment.
  • FIG. 10 is a diagram illustrating an example of an internal configuration of a switching device according to a fourth embodiment.
  • FIG. 10 is a diagram illustrating an example of an internal configuration of a switching device according to a fifth embodiment.
  • FIG. 20 is a diagram illustrating an example of an internal configuration of a switching device according to a sixth embodiment.
  • FIG. 10 is an example of an external view of a MOSFET in a second embodiment.
  • FIG. 10 is a diagram illustrating an example of an internal configuration of a switching device according to a third embodiment.
  • FIG. 10 is a diagram illustrating an example of an internal configuration of a switching device according to a fourth embodiment.
  • FIG. 10
  • FIG. 20 is a diagram illustrating an example of an internal configuration of a switching device according to a seventh embodiment.
  • FIG. 20 is a diagram illustrating an example of an internal configuration of a switching device according to an eighth embodiment.
  • FIG. 20 is a diagram illustrating an example of an internal configuration of a switching device according to a ninth embodiment. It is a block diagram which shows a part of structure of the solar energy power generation system in Embodiment 10.
  • FIG. It is a figure which shows an example of the internal structure of the detection part in each embodiment. It is a figure which shows another example of the internal structure of the detection part in each embodiment.
  • It is a conceptual diagram which illustrates a part of structure of a solar energy power generation system.
  • FIG. 1 is a configuration diagram showing the configuration of the photovoltaic power generation system according to the first embodiment.
  • a solar power generation system 500 is a system that generates power using solar energy.
  • the solar power generation system 500 includes a failure detection device 200, a solar cell array 300, and a load device 400.
  • a solar cell string 12 (an example of a solar cell) is configured by a plurality of solar cell modules 10a to 10d (an example of a solar cell) electrically connected in series.
  • Each solar cell module 10 is a module that converts solar energy into electrical energy and outputs it as DC power.
  • the solar cell array 300 includes a plurality of solar cell strings 12a to 12d arranged in parallel.
  • each solar cell string 12 is configured by four solar cell modules 10a to 10d connected in series, but is not limited to this.
  • the number in series may be two, three, or five or more. What is necessary is just to set suitably.
  • the solar cell array 300 includes four solar cell strings 12a to 12d connected in parallel, but is not limited thereto.
  • the number in parallel may be two, three, or five or more. What is necessary is just to set suitably.
  • a switch mechanism 100 In the failure detection device 200, a switch mechanism 100, switching devices 31 and 33, a detection unit 36, a control unit 38, and a gate drive circuit 104 are arranged.
  • the switch mechanism 100 includes a plurality of switching devices 102a to 102h.
  • the positive electrode (+) or the negative electrode ( ⁇ ) of the solar cell string 12 is connected to one side of each switching device 102.
  • a backflow prevention diode 20 or a backflow prevention diode 21 is connected to the other side of each switching device 102.
  • the backflow prevention diodes 20 and 21 are arranged such that the direction in which the current supplied from the solar cell string 12 flows is the forward direction.
  • the number of switching devices 102 that can be arranged at both poles of the solar cell string 12 is arranged.
  • the negative electrode ( ⁇ ) of the solar cell string 12a is connected to one side of the switching device 102a.
  • a backflow prevention diode 21a is connected to the other side of the switching device 102a.
  • the backflow prevention diode 21a is arranged so that the forward direction is directed to the negative electrode ( ⁇ ) of the solar cell string 12a.
  • the positive electrode (+) of the solar cell string 12a is connected to one side of the switching device 102b.
  • a backflow prevention diode 20a is connected to the other side of the switching device 102b.
  • the backflow prevention diode 20a is disposed so that the forward direction is opposite to the direction toward the positive electrode (+) of the solar cell string 12a.
  • the negative electrode ( ⁇ ) of the solar cell string 12b is connected to one side of the switching device 102c.
  • a backflow prevention diode 21b is connected to the other side of the switching device 102c.
  • the backflow prevention diode 21b is arranged so that the forward direction is directed to the negative electrode ( ⁇ ) of the solar cell string 12b.
  • the positive electrode (+) of the solar cell string 12b is connected to one side of the switching device 102d.
  • a backflow prevention diode 20b is connected to the other side of the switching device 102d.
  • the backflow prevention diode 20b is disposed so that the forward direction is opposite to the direction toward the positive electrode (+) of the solar cell string 12b.
  • the negative electrode ( ⁇ ) of the solar cell string 12c is connected to one side of the switching device 102e.
  • a backflow prevention diode 21c is connected to the other side of the switching device 102e.
  • the backflow prevention diode 21c is arranged so that the forward direction is directed to the negative electrode ( ⁇ ) of the solar cell string 12c.
  • the positive electrode (+) of the solar cell string 12c is connected to one side of the switching device 102f.
  • a backflow prevention diode 20c is connected to the other side of the switching device 102f.
  • the backflow prevention diode 20c is arranged so that the forward direction is opposite to the direction toward the positive electrode (+) of the solar cell string 12c.
  • the negative electrode ( ⁇ ) of the solar cell string 12d is connected to one side of the switching device 102g.
  • a backflow prevention diode 21d is connected to the other side of the switching device 102g.
  • the backflow prevention diode 21d is arranged so that the forward direction is directed to the negative electrode ( ⁇ ) of the solar cell string 12d.
  • the positive electrode (+) of the solar cell string 12d is connected to one side of the switching device 102h.
  • a backflow prevention diode 20d is connected to the other side of the switching device 102h.
  • the backflow prevention diode 20d is disposed so that the forward direction is opposite to the direction toward the positive electrode (+) of the solar cell string 12d.
  • the backflow prevention diodes 20a to 20d are connected to the circuit breaker 402 in parallel. Each of the backflow prevention diodes 21a to 21d is connected to the circuit breaker 404 in parallel. Circuit breakers 402 and 404 are connected to load device 400, respectively. As described above, the positive electrode (+) side of the solar cell array 300 is connected to the load device 400 via the circuit breaker 402, and the negative electrode ( ⁇ ) side is connected to the load device 400 via the circuit breaker 404.
  • the load device 400 consumes or converts the power generated by the plurality of solar cell strings 12. Examples of the load device 400 include a power conditioner. The DC power supplied from the solar cell array 300 to the load device 400 is converted into, for example, three-phase AC power in the load device 400 and supplied to, for example, a commercial power system.
  • each solar cell string 12 branches in parallel with the switching device 102 and is connected to a corresponding switch of the switching device 31 constituted by a plurality of switches.
  • the negative electrode ( ⁇ ) side of each solar cell string 12 branches in parallel with the switching device 102 and is connected to a corresponding switch of the switching device 33 constituted by a plurality of switches.
  • Each switch of the switching devices 31 and 33 is connected to the detection unit 36.
  • the detection unit 36 performs failure detection as will be described later based on the control by the control unit 38. Failure detection is performed for each solar cell string 12, and when performing failure detection, the control unit 38 causes the switching device 102 connected to both poles of the solar cell string 12 to be inspected to be opened (OFF). A control signal is transmitted to the gate drive circuit 104. The gate drive circuit 104 controls the corresponding switching device 102 to be opened (OFF). Thereafter, the control unit 38 controls the switching devices 31 and 33 connected to both poles of the solar cell string 12 to be inspected to be closed (ON). With this operation, the solar cell string 12 to be inspected is electrically disconnected from the solar power generation system and connected to the detection unit 36. In FIG. 1, for convenience, a plurality of switching devices 102 are illustrated as being connected in series to the gate drive circuit 104, but each switching device 102 receives a control signal from the gate drive circuit 104 in parallel. .
  • FIG. 2 is a diagram illustrating an example of an internal configuration of the switching device according to the first embodiment.
  • the switching device 102 uses two MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) 30 and 40 in combination.
  • the MOSFET 30 (first semiconductor element) includes a transistor unit 34 that performs switching between the source and the drain, and a diode unit 32 (parasitic diode) that allows a current to flow in a predetermined direction between the source and the drain of the transistor unit 34.
  • the MOSFET 40 (second semiconductor element) includes a transistor unit 44 that performs switching between the source and the drain, and a diode unit 42 (parasitic diode) that flows current in a predetermined direction between the source and the drain of the transistor unit 44.
  • a MOSFET as the switching device 102, the power required for the opening / closing operation can be reduced.
  • the MOSFET 30 is arranged in the middle of the wiring connecting the solar cell string 12 and the load device 400.
  • the MOSFET 30 functions as an opening / closing unit that opens and closes the wiring.
  • the MOSFET 40 is arranged in series with the MOSFET 30 in the middle of such wiring.
  • the MOSFET 40 functions as a blocking unit that blocks current flowing through the diode unit 32 included in the MOSFET 30.
  • the MOSFET 30 and the MOSFET 40 are connected in series so that the diode portions 32 and 42 included in the MOSFET 30 and the MOSFET 40 are in opposite directions.
  • n-type enhancement type FETs are used as the MOSFETs 30 and 40.
  • MOSFETs 30 and 40 are connected in series so that the source sides thereof face each other. By connecting the sources to each other, the gates of the MOSFETs 30 and 40 can be set to the same potential. In the first embodiment, MOSFETs 30 and 40 are driven simultaneously. Therefore, the ON / OFF operation of the MOSFETs 30 and 40 can be controlled by one system of gate voltage signals. In FIG. 2, the gate portion is indicated by a dotted line so as to identify the enhancement type.
  • the same switching devices 102a to 102f are connected to both poles of the solar cell strings 12a to 12c. 2, the description of the configuration of the solar cell string 12d among the four solar cell strings 12a to 12d in FIG. 1 is omitted.
  • An opening operation (OFF) for electrically disconnecting one corresponding pole of the device 400 and a closing operation (ON) for connection are performed.
  • the control unit 38 sends a control signal for turning off the gate to the gate drive circuit 104 to the switching devices 102a and 102b. Output.
  • the gate drive circuit 104 the positive source-gate voltage applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102a is turned off. Thereby, both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off (OFF) between the source and the drain.
  • the MOSFET 40 blocks the current flowing through the diode unit 32 included in the MOSFET 30 in a state where the wiring is controlled to be opened (OFF) by the MOSFET 30. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the positive source-gate voltage applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102b is turned off.
  • both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off (OFF) between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off.
  • the MOSFET 40 blocks the current flowing through the diode portion 32 included in the MOSFET 30 in the state where the wiring is controlled to be opened (OFF) by the MOSFET 30 as in the case of the negative electrode side. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the timing for turning off the source-gate voltage applied to the switching devices 102a and 102b is preferably the same, but may be shifted. Then, after both the switching devices 102a and 102b are turned off and the solar cell string 12a is electrically disconnected from the other solar cell strings 12b and the load device 400, the control unit 38 controls the switching device 31. , 33, each switch corresponding to the solar cell string 12a is turned on (closed). Thereby, the solar cell string 12a can be connected to the detector 36. Further, inflow of current from the other solar cell strings 12b and the load device 400 to the detection unit 36 can be avoided.
  • the solar cell string 12a is electrically connected to the other solar cell string 12b and the load device 400.
  • the switches corresponding to the solar cell string 12a among the switching devices 31 and 33 based on the control of the control unit 38 are turned off (opened).
  • a source-gate voltage may be applied to the switching devices 102a and 102b.
  • the solar cell string 12a can be returned to the power generation system.
  • the opening / closing operations of the switching devices 102c, d, etc. for the other solar cell strings 12b are the same as those of the solar cell string 12a.
  • FIG. 3 is a cross-sectional view showing an example of the MOSFET according to the first embodiment.
  • a large voltage of several hundred volts is generated from the solar cell string.
  • a voltage of about 500V is generated.
  • a large current of several A or several 10 A flows.
  • a current of 10 A flows.
  • a MOSFET that can withstand such a large voltage and large current load is used.
  • a vertical MOSFET which is a power semiconductor element.
  • FIG. 3 for example, an example of a cross section of an n-type vertical MOSFET is shown.
  • FIG. 3 for example, an example of a cross section of an n-type vertical MOSFET is shown.
  • FIG. 3 for example of FIG.
  • a p-well is formed in an n-type semiconductor substrate, and an n-well is formed in the p-well.
  • a gate (G) is formed on the p-well between the n-well and the n-type semiconductor substrate.
  • the source (S) electrode is formed on the n-well so as to straddle the p-well opposite to the gate.
  • the drain (D) electrode is formed on the back surface of the n-type semiconductor substrate.
  • a transistor portion is formed by the gate (G), the source (S), and the drain (D).
  • FIG. 4 is a diagram illustrating an example of a solar cell array and a switching device, which is a comparative example of the first embodiment.
  • the MOSFET 50 includes a transistor portion 54 and a diode portion 52 that serves as the parasitic diode described above.
  • the bipolar MOSFETs 50 are arranged such that the forward direction of the diode part 52 is opposite to the direction in which current flows from the solar cell string 12.
  • reverse current preventing diodes 20 and 21 are arranged at both poles of the solar cell string 12a so that the forward direction is opposite to the direction in which current flows from the solar cell string 12.
  • the failure detection target solar cell string 12 a is disconnected from the load and other solar cell strings because the MOSFETs 54 connected to both poles thereof are OFF, and as a result, the failure detection target solar cell string 12 a.
  • the potential on the positive electrode (+) side of the solar cell string is higher than the potential on the positive electrode (+) side of the other solar cell strings, and the potential on the negative electrode ( ⁇ ) side of the solar cell string 12a to be detected is the other solar cell string. In this case, the potential is lower than the potential on the negative electrode ( ⁇ ) side.
  • the positive electrode (+) of the solar cell string to be inspected has a higher potential than the positive electrodes (+) of other solar cell strings that are generating power, the current from the system that is generating power even if there is a parasitic diode Is not affected because it does not flow.
  • the negative electrode of the solar cell string to be inspected is at a lower potential than the negative electrode of the solar cell string during power generation, even if there is a parasitic diode, current will not flow to the system during power generation, so it will be affected. Absent.
  • FIG. 5 is a diagram showing another example of the solar cell array and the switching device, which is a comparative example of the first embodiment.
  • the potential on the positive electrode (+) side of the failure detection target solar cell string 12a is higher than the potential on the positive electrode (+) side of the other solar cell strings, and the failure detection target solar cell string 12a
  • Other configurations are the same as those in FIG. In this case, the positive electrode (+) side of the solar cell string to be inspected is not affected by the system during power generation, as in FIG.
  • the parasitic diode causes a current to flow to the generating system, which is affected.
  • Such an influence can be avoided to some extent by the blocking diode 21, but the avoidance is incomplete because the reverse current cannot be completely blocked.
  • FIG. 6 is a diagram illustrating another example of a solar cell array and a switching device, which are comparative examples of the first embodiment.
  • the potential on the positive electrode (+) side of the failure detection target solar cell string 12 a is the potential on the positive electrode (+) side of another solar cell string due to the action of a failure detection device (an example will be described later). It shows a case where the potential on the negative electrode ( ⁇ ) side of the failure detection target solar cell string 12a is lower than the potential on the negative electrode ( ⁇ ) side of the other solar cell strings.
  • Other configurations are the same as those in FIG. In such a case, the negative electrode ( ⁇ ) side of the failure detection target solar cell string 12a is not affected by the system during power generation, as described with reference to FIG.
  • the parasitic diode causes a current to flow from the system that is generating power. Receive. This effect can be avoided to some extent by the blocking diode 20, but the avoidance is incomplete because the reverse current cannot be completely blocked.
  • FIG. 7 is a diagram illustrating another example of the solar cell array and the switching device, which are comparative examples of the first embodiment.
  • the potential on the positive electrode (+) side of the failure detection target solar cell string 12 a is the potential on the positive electrode (+) side of another solar cell string due to the action of a failure detection device (an example will be described later).
  • the potential on the negative electrode ( ⁇ ) side of the failure detection target solar cell string 12a is lower than the potential on the negative electrode ( ⁇ ) side of other solar cell strings due to the action of the failure detection device (example will be described later). It shows a high case.
  • Other configurations are the same as those in FIG.
  • the positive electrode (+) of the solar cell string 12a to be detected has a lower potential than the positive electrode of the power generation string, current flows from the system that is generating power due to the parasitic diode as described with reference to FIG. Therefore, it is affected by the power generation system.
  • This effect can be avoided to some extent by the blocking diode 20, but the avoidance is incomplete because the reverse current cannot be completely blocked.
  • the negative electrode of the solar cell string to be inspected has a higher potential than the negative electrode of the solar cell string during power generation, current will flow to the system during power generation due to the parasitic diode as described with reference to FIG. So affected.
  • Such an influence can be avoided to some extent by the blocking diode 21, but the avoidance is incomplete because the reverse current cannot be completely blocked.
  • the diode parts 32 and 42 included in the two MOSFETs 30 and 40 are connected in series so as to be opposite to each other. Therefore, the problem by a parasitic diode can be avoided.
  • the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the electric power required for the opening / closing operation and maintaining the durability. Therefore, it is possible to detect ground faults with high accuracy.
  • the present invention is not limited to this.
  • the present invention is not limited to this.
  • other connection methods will be described.
  • the configuration of the photovoltaic power generation system 500 in the second embodiment is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
  • FIG. 8 is a diagram illustrating an example of an internal configuration of the switching device according to the second embodiment.
  • n-type enhancement type FETs are used as the MOSFETs 30 and 40 as in FIG. However, in FIG. 8, they are connected in series so that the drain sides of the MOSFETs 30 and 40 face each other. When the drains are connected to each other, the potential required for the source-gate voltage is different. Therefore, it is preferable to provide a separate signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40.
  • the MOSFETs 30 and 40 are driven simultaneously, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by the two gate voltage signals.
  • Other configurations are the same as those in FIG.
  • FIG. 9 is an example of an external view of the MOSFET in the second embodiment.
  • a heat radiating plate 62 is disposed outside the MOSFET 60.
  • the heat radiating plate 62 is connected to the drain. Therefore, when the drains are connected, there is no need to pay attention to the insulation between the heat sinks when arranging the heat sinks of the MOSFETs 30 and 40, and a common and large heat sink can be used.
  • the thermal design of the device becomes easy.
  • the control unit 38 when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104.
  • the gate drive circuit 104 the positive source-gate voltage applied to the respective gate wirings of the MOSFETs 30 and 40 of the switching device 102a is turned off.
  • both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode ( ⁇ ) of the solar cell string 12a is assumed to be negative (The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the positive source-gate voltage applied to the respective gate wirings of the MOSFETs 30 and 40 of the switching device 102b is turned off.
  • both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
  • n-type enhancement type FETs are used as the MOSFETs 30 and 40.
  • the present invention is not limited to this.
  • the third embodiment a case where another MOSFET is used will be described.
  • the configuration of photovoltaic power generation system 500 in Embodiment 3 is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
  • FIG. 10 is a diagram illustrating an example of an internal configuration of the switching device according to the third embodiment.
  • p-type enhancement type FETs are used as the MOSFETs 30 and 40. Therefore, the polarity of the source-gate voltage is opposite to that in the first embodiment.
  • Other configurations are the same as those in FIG. That is, in FIG. 10, the source sides of the MOSFETs 30 and 40 are connected in series so as to face each other, so that the source-gate voltage can be made the same potential, so that the gate drive circuit 104 from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40 A signal line can be shared.
  • the MOSFETs 30 and 40 are driven simultaneously, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by one system gate voltage signal.
  • the control unit 38 when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104.
  • the negative source-gate voltage applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102a is turned off.
  • both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode ( ⁇ ) of the solar cell string 12a is assumed to be negative (The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the negative source-gate voltage applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102b is turned off.
  • both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 interrupt the source and drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
  • the present invention is not limited to this.
  • other connection methods will be described.
  • the configuration of the photovoltaic power generation system 500 in Embodiment 4 is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
  • FIG. 11 is a diagram illustrating an example of the internal configuration of the switching device according to the fourth embodiment.
  • p-type enhancement type FETs are used as the MOSFETs 30 and 40 in the same manner as in FIG.
  • the MOSFETs 30 and 40 are connected in series so that the drain sides face each other.
  • the potential required for the source-gate voltage is different. Therefore, it is preferable to provide a separate signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40.
  • the MOSFETs 30 and 40 are simultaneously driven, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by the two systems of gate voltage signals.
  • Other configurations are the same as those in FIG.
  • the heat dissipation plates of the MOSFETs 30 and 40 can be connected to each other, so that the heat dissipation of the element can be improved.
  • the control unit 38 when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104.
  • the negative source-gate voltage applied to the respective gate wirings of the MOSFETs 30 and 40 of the switching device 102a is turned off.
  • both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode ( ⁇ ) of the solar cell string 12a is assumed to be negative (The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the negative source-gate voltage applied to the respective gate wirings of the MOSFETs 30 and 40 of the switching device 102b is turned off.
  • both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
  • n-type enhancement type FETs are used as the MOSFETs 30 and 40.
  • the present invention is not limited to this.
  • the fifth embodiment a case where another MOSFET is used will be described.
  • the configuration of the photovoltaic power generation system 500 in the fifth embodiment is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
  • FIG. 12 is a diagram illustrating an example of an internal configuration of the switching device according to the fifth embodiment.
  • n-type depletion type FETs are used as the MOSFETs 30 and 40. Therefore, a source-gate voltage is applied during the OFF operation. At this time, as the applied voltage, a voltage having a polarity opposite to that in the ON operation in the first embodiment is applied.
  • Other configurations are the same as those in FIG. That is, in FIG. 12, the source sides of the MOSFETs 30 and 40 are connected in series so that they face each other, so that the source-gate voltage can be made the same potential, so that the gate drive circuit 104 from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40 A signal line can be shared.
  • the MOSFETs 30 and 40 are driven simultaneously, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by a single system gate voltage signal.
  • the gate portion is shown by a solid line so as to identify the depletion type.
  • the depletion type FET is normally ON in which a current flows between the source and the drain when no voltage is applied to the gate. Therefore, each solar cell string 12 can supply the generated power to the load device 400 even when no voltage is applied to the gates of the MOSFETs 30 and 40 of the corresponding switching device 102. Therefore, in the fifth embodiment, the gate drive circuit 104 is connected so as to be supplied with power from the wiring connecting the plurality of solar cell strings 12 and the load device 400. As a result, such power can be used as a power source for the gate that drives the transistor portions 34 and 44 of the MOSFETs 30 and 40, respectively. Therefore, a separate power source can be eliminated.
  • the control unit 38 when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104.
  • a negative source-gate voltage is applied to the gate wiring common to the MOSFETs 30 and 40 of the switching device 102a.
  • both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode ( ⁇ ) of the solar cell string 12a is assumed to be negative (The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • a negative source-gate voltage is applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102b.
  • both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
  • FIG. 13 is a diagram illustrating an example of the internal configuration of the switching device according to the sixth embodiment.
  • n-type depletion type FETs are used as the MOSFETs 30 and 40 as in FIG. 12.
  • the MOSFETs 30 and 40 are connected in series so that the drain sides face each other. When the drains are connected to each other, the potential required for the source-gate voltage is different. Therefore, it is preferable to provide a separate signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40.
  • the MOSFETs 30 and 40 are driven simultaneously, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by two gate voltage signals.
  • Other configurations are the same as those in FIG.
  • the heat dissipation plates of the MOSFETs 30 and 40 can be connected to each other, so that the heat dissipation of the element can be improved.
  • a depletion type FET is used. Therefore, in the sixth embodiment, similarly to the fifth embodiment, the gate drive circuit 104 is connected so as to be supplied with electric power from the wiring connecting the plurality of solar cell strings 12 and the load device 400. As a result, such power can be used as a power source for the gate that drives the transistor portions 34 and 44 of the MOSFETs 30 and 40, respectively. Therefore, a separate power source can be eliminated.
  • the control unit 38 when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104.
  • a negative source-gate voltage is applied to each gate wiring of the MOSFETs 30 and 40 of the switching device 102a.
  • both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode ( ⁇ ) of the solar cell string 12a is assumed to be negative (The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • a negative source-gate voltage is applied to the respective gate wirings of the MOSFETs 30 and 40 of the switching device 102b.
  • both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
  • n-type depletion type FETs are used as the MOSFETs 30 and 40.
  • the present invention is not limited to this.
  • the seventh embodiment a case where another MOSFET is used will be described.
  • the configuration of solar power generation system 500 in Embodiment 7 is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
  • FIG. 14 is a diagram illustrating an example of an internal configuration of the switching device according to the seventh embodiment.
  • p-type depletion type FETs are used as the MOSFETs 30 and 40.
  • the polarity of the source-gate voltage is opposite to that in the fifth embodiment.
  • Other configurations are the same as those in FIG. That is, in FIG. 14, the source sides of the MOSFETs 30 and 40 are connected in series so that they face each other, and the voltage between the source and gate can be made the same potential, so the signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40 is connected. Can be common.
  • the MOSFETs 30 and 40 are simultaneously driven, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by one system of gate voltage signals.
  • Other configurations are the same as those in FIG.
  • a depletion type FET is used. Therefore, in the seventh embodiment, as in the fifth embodiment, the gate drive circuit 104 is connected so as to receive power supply from the wiring connecting the plurality of solar cell strings 12 and the load device 400. As a result, such power can be used as a power source for the gate that drives the transistor portions 34 and 44 of the MOSFETs 30 and 40, respectively. Therefore, a separate power source can be eliminated.
  • the control unit 38 when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104.
  • a positive source-gate voltage is applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102a.
  • both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode ( ⁇ ) of the solar cell string 12a is assumed to be negative (The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • a positive source-gate voltage is applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102b.
  • both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
  • the case where the sources of the p-type depletion type FETs are connected to each other as the MOSFETs 30 and 40 has been described.
  • the fourth embodiment other connection methods will be described.
  • the configuration of the photovoltaic power generation system 500 in the eighth embodiment is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
  • FIG. 15 is a diagram illustrating an example of the internal configuration of the switching device according to the eighth embodiment.
  • p-type depletion type FETs are used as the MOSFETs 30 and 40 as in FIG. 14.
  • the MOSFETs 30 and 40 are connected in series so that the drain sides face each other. When the drains are connected to each other, the potential required for the source-gate voltage is different. Therefore, it is preferable to provide a separate signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40.
  • the MOSFETs 30 and 40 are simultaneously driven, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by the two systems of gate voltage signals.
  • Other configurations are the same as those in FIG.
  • the heat dissipation plates of the MOSFETs 30 and 40 can be connected to each other, so that the heat dissipation of the element can be improved.
  • a depletion type FET is used. Therefore, in the eighth embodiment, similarly to the fifth embodiment, the gate drive circuit 104 is connected so as to receive power supply from the wiring connecting the plurality of solar cell strings 12 and the load device 400. As a result, such power can be used as a power source for the gate that drives the transistor portions 34 and 44 of the MOSFETs 30 and 40, respectively. Therefore, a separate power source can be eliminated.
  • the control unit 38 when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning the gate OFF to the switching devices 102a and 102b. Output to the drive circuit 104.
  • a positive source-gate voltage is applied to each gate wiring of the MOSFETs 30 and 40 of the switching device 102a.
  • both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode ( ⁇ ) of the solar cell string 12a is assumed to be negative (The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • a positive source-gate voltage is applied to each gate wiring of the MOSFETs 30 and 40 of the switching device 102b.
  • both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
  • the present invention is not limited to this.
  • the ninth embodiment a case where different types of MOSFETs are used as the MOSFETs 30 and 40 will be described.
  • the configuration of solar power generation system 500 in the ninth embodiment is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
  • FIG. 16 is a diagram illustrating an example of an internal configuration of the switching device according to the ninth embodiment.
  • an n-type enhancement type FET is used as the MOSFET 30.
  • a p-type depletion type FET is used as the MOSFET 40.
  • the source side of the MOSFET 30 and the drain side of the MOSFET 40 are connected in series so as to face each other.
  • a signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40 may be provided separately.
  • the MOSFETs 30 and 40 are driven simultaneously, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by two systems of gate voltage signals.
  • Other configurations are the same as those in FIG.
  • the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104.
  • the positive source-gate voltage applied to the gate wiring of the MOSFET 30 of the switching device 102a is turned off.
  • a positive source-gate voltage is applied to the gate wiring of the MOSFET 40 of the switching device 102a.
  • both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode ( ⁇ ) of the solar cell string 12a is assumed to be negative (The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • the positive source-gate voltage applied to the gate wiring of the MOSFET 30 of the switching device 102b is turned off.
  • a positive source-gate voltage is applied to the gate wiring of the MOSFET 40 of the switching device 102a.
  • both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain.
  • the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
  • an enhancement type MOSFET may be used for one of the MOSFETs 30 and 40 and a depletion type MOSFET may be used for the other.
  • a depletion type MOSFET may be used for the other.
  • the solar cell is electrically removed from the photovoltaic power generation system while reducing the power required for the opening / closing operation. Can be separated.
  • Embodiments 1 to 9 as shown in FIG. 1, the diodes 20 and 21 for backflow prevention are arranged in the failure detection apparatus 200, but the present invention is not limited to this. In the tenth embodiment, other configurations will be described.
  • FIG. 17 is a configuration diagram illustrating a part of the configuration of the photovoltaic power generation system according to the tenth embodiment.
  • the photovoltaic power generation system 500 includes a failure detection device 200, connection boxes 202 and 204, a solar cell array 300, and a load device 400 (not shown).
  • the load device 400 not shown.
  • the backflow prevention diodes 20a to 20d on the positive electrode (+) side of the solar cell strings 12a to 12d, a circuit breaker 402, and switches 22a to 22d such as a circuit breaker or a disconnect circuit are disposed in the junction box 204, and the reverse current preventing diodes 21a to 21d on the positive electrode (+) side of each of the solar cell strings 12a to 12d, a circuit breaker 404, and a switch 24a such as a circuit breaker or disconnector. 1 is the same as FIG. 1 except that .about.d are arranged.
  • the junction boxes 202 and 204 may be prepared separately from the failure detection apparatus 200.
  • FIG. 18 is a diagram illustrating an example of the internal configuration of the detection unit in each embodiment.
  • one solar cell string 12a is selected from a plurality of solar cell strings (S1).
  • the switching devices 102a and 102b for disconnection corresponding to the positive electrode side and the negative electrode side of the selected one solar cell string 12a are turned off.
  • the said solar cell string 12a is electrically disconnected from the photovoltaic power generation system 500, and is disconnected, and it is set as a disconnected state (S2).
  • the switching devices 31 and 33 connected to the positive electrode side and the negative electrode side in the disconnected solar cell string 12a are closed (ON), and the solar cell string 12a is connected to the detection unit 36 (S3).
  • the positive electrode side switch element 8x shown in FIG. 18 is turned on, the negative electrode side switch element 8y is turned off, and only the positive electrode side is connected to the other side of the detection resistor 9.
  • the negative electrode side is released (S4).
  • the voltage detector 6 measures the first voltage drop value of the detection resistor 9 and its sign (S5).
  • the switch element 8 switches on and off according to an instruction signal from the control unit 38.
  • the positive electrode side switch element 8x is turned off and the negative electrode side switch element 8y is turned on, and only the negative electrode side is connected to the other side of the detection resistor 9 and the positive electrode side is released. (S6).
  • the voltage detector 6 measures the second voltage drop value of the detection resistor 9 and its sign (S7).
  • both the positive electrode side switch element 8x and the negative electrode side switch element 8y are turned off and disconnected (disconnected) from the detection resistor 9.
  • the voltage detector 6 measures the voltage value between the electrodes of the solar cell string 103 and its sign (S8, 9). Note that S4, 5, S6, 7 and S8, 9 are out of order with each other, and S6, 7 may be performed first, or S8, 9 may be performed first. .
  • the control part 38 calculates an insulation resistance value using the measured 1st and 2nd voltage drop value, the voltage value between electrodes, and these codes
  • symbols (S10). Specifically, the insulation resistance value R leak is calculated using the following equation (1). (1) R leak R d ⁇
  • R d resistance value of the detection resistor 9
  • V 0 Inter-electrode voltage value
  • V 1 First voltage drop value
  • V 2 Second voltage drop value
  • control unit 38 compares the calculated insulation resistance value R leak with a preset reference resistance value, and performs a ground fault determination (S11). Specifically, if the calculated insulation resistance value R leak is equal to or greater than the reference resistance value, it is determined that there is no ground fault. On the other hand, if the insulation resistance value R leak is less than the reference resistance value, “ground fault exists”. Is determined.
  • the disconnection switching devices 102a and 102b are turned on and connected to the photovoltaic power generation system 500 for the disconnection solar cell string 12a. Then, the switching devices 31 and 33 for measurement are turned off and separated from the detection unit 36.
  • the solar cell strings 12 constituting the solar cell array 300 are disconnected from the photovoltaic power generation system 500, and the solar cell strings 12 in the disconnected state are separated. Detecting a ground fault.
  • the ground capacitance of the ground fault detection target can be reduced (that is, the electric circuit of the ground fault detection target is shortened and the total area is reduced). It is possible to reduce the adverse effect of the current flowing due to the ground capacitance on ground fault detection.
  • the solar cell string 12 is electrically disconnected from the load device 400 such as a power conditioner at the time of detecting a ground fault. Therefore, the adverse effect of noise generated due to the power conditioner reaches the ground fault detection. Can also be suppressed. Therefore, according to the present embodiment, it is possible to reliably detect a ground fault.
  • the detection unit 36 is connected to both the positive electrode (+) side and the negative electrode side of the solar cell string 12 .
  • the present invention is not limited to this, and the positive electrode (+) side is not limited thereto. Or it is good also as a structure connected to a negative electrode side.
  • FIG. 19 is a diagram illustrating another example of the internal configuration of the detection unit in each embodiment.
  • the detection unit 36 includes a first grounding circuit 81A, a first resistor 84A, a first DC power supply 82A and a first ammeter 86A, a second grounding circuit 81B, a second resistor 84B, A second measurement system including a second DC power supply 82B and a second ammeter 86B.
  • the first grounding electric circuit 81A has one side connected to the ground G.
  • the other side of the first grounding electric circuit 81A can be connected to the wiring (electric circuit) on the positive electrode (+) side of the solar cell string 12a to be detected.
  • the other side of the first grounding electric circuit 81A is connected to the positive (+) side wiring of the solar cell string 12a through the first switch unit 80A and the switching device 31.
  • the first switch unit 80A switches the electrical connection / disconnection of the first grounding electric circuit 81A with respect to the solar cell string 12a.
  • a semiconductor switch such as an FET or a mechanical switch such as a relay switch can be used.
  • the first switch unit 80A is connected to the control unit 38 and switches on and off according to an instruction signal from the control unit 38.
  • the first resistor 84A is provided between the first switch unit 80A and the ground G on the first grounding electric circuit 81A.
  • Resistance R d of the first resistor 84A is in terms of safety upon the ground fault occurs or exceeds a predetermined lower limit value, and is equal to or less than a predetermined upper limit value in terms of measuring the ease of measurement (hereinafter The same applies to the first resistor 84B).
  • the first DC power supply 82A is provided between the first switch section 80A and the first resistor 84A (on the solar cell string 12a side with respect to the first resistor 84A) on the first grounding electric circuit 81A. That is, the first DC power supply 82A has one side as the negative electrode side connected to the first resistor 84A and the other side as the positive electrode side connected to the positive electrode side of the solar cell string 12a via the first switch portion 80A. Yes.
  • the first DC power supply 82A applies a positive DC voltage (DC voltage) to the positive electrode side of the solar cell string 12a.
  • the first DC power source 82A applies a first DC voltage of the DC voltage value V 1.
  • the first DC voltage value V 1 is set to a predetermined lower limit value or more from the viewpoint of improving the sensitivity of ground fault detection, and is set to a predetermined upper limit value or less from the viewpoint of preventing damage to the solar cell circuit to be measured (the following Same for DC voltage value).
  • the first DC power supply 82A is connected to the control unit 38, first applying a DC voltage value V 1 in response to an instruction signal from the control unit 38.
  • the first ammeter 86A is provided between the first resistor 84A and the ground G on the first grounding electric circuit 81A.
  • the first ammeter 86A is the first current value as the leakage current value at the first ground path 81A flows through the first resistor 84A (first measurement) is measured I 1.
  • the first ammeter 86A is connected to the control unit 38, first to perform the measurement of the DC voltage value V 1 in response to an instruction signal from the control unit 38.
  • a DC zero-phase current detector using a Hall element is used as the first ammeter 86A.
  • one side of the second grounding electric circuit 81B is connected to the ground G.
  • the other side of the second grounding electric circuit 81B is connectable to the positive wiring (electric circuit) of the solar cell string 12a.
  • the other side of the second grounding electric circuit 81B is connected to the positive electrode side wiring of the solar cell string 12a via the second switch unit 80B and the switching device 31.
  • the second switch unit 80B switches electrical connection / disconnection of the second grounding electric circuit 81B with respect to the solar cell string 12a.
  • a semiconductor switch such as an FET or a mechanical switch such as a relay switch can be used.
  • the second switch unit 80B is connected to the control unit 38 and switches on and off according to an instruction signal from the control unit 38.
  • the second resistor 84B is provided between the second switch unit 80B and the ground G on the second grounding electric circuit 81B. Resistance of the second resistor 84B are preferable to the equal resistance value R d and the first resistor 84A.
  • the second DC power source 82B is provided between the second switch unit 80B and the first resistor 84B (on the solar cell string 12a side with respect to the second resistor 22B) on the second ground circuit 81B. That is, the second DC power supply 82B has one side as the negative electrode side connected to the second resistor 84B, and the other side as the positive electrode side connected to the positive electrode side of the solar cell string 12a via the second switch portion 80B. Yes.
  • the second DC power supply 82B applies a positive DC voltage (DC voltage) to the positive electrode side of the solar cell string 12a.
  • the second DC power source 82B applies a second DC voltage of the DC voltage value V 2.
  • Second DC voltage V 2 is different from the voltage value from the first DC voltage value V 1.
  • the second DC power supply 82B is connected to the control unit 38, the second applying a DC voltage value V 2 in response to an instruction signal from the control unit 38.
  • the second ammeter 86B is provided between the second resistor 84B and the ground G on the second grounding electric circuit 81B.
  • the second ammeter 86B is a second current value as the leakage current value in the second ground path 81B flows through the second resistor 84B (second measured value) is measured I 2.
  • the second ammeter 86B is connected to the control unit 38, the second performs measurement of the DC voltage value V 2 in response to an instruction signal from the control unit 38.
  • a DC zero-phase current detector using a Hall element or the like is used similarly to the first ammeter 24A.
  • a voltage application location where the first DC voltage value V 1 is applied from the first DC power supply 82A, and a voltage application location where the second DC voltage value V 2 is applied from the second DC power supply 82B. are equal to each other at least when the rated output of the solar cell string 12a is assumed. In other words, the design potentials of the first and second predetermined portions are equal to each other.
  • control unit 38 has a ground fault detection function for performing calculation based on the measurement result, detecting the insulation resistance value R L and the potential V L of the ground fault location T, and detecting (determining) the presence or absence of the ground fault. is doing.
  • the first switch portion 80A is turned on, the first grounding electric circuit 81A is connected to the positive electrode side of the solar cell string 12a, the second switch unit 80B is kept off, and the second grounding electric circuit 81B is connected to the solar cell string 12a. Not connected to the positive electrode side.
  • the first DC power source 82A applying a first DC voltage value V 1 of the positive voltage to the positive electrode side of the solar cell string 12a.
  • the first current value I 1 flowing in the first ground path 81A is measured by ammeter 86A.
  • the first switch unit 80A is turned off, the first grounding circuit 81A is disconnected from the positive electrode side of the solar cell string 12a, the second switch unit 80B is turned on, and the second grounding circuit 81B is connected to the solar cell string. It connects with the positive electrode side of 12a.
  • the second DC power source 82B applying a second DC voltage value V 2 of the positive voltage to the positive electrode side of the solar cell string 12a.
  • the second current value I 2 flowing in the first ground path 81B is measured by a current meter 86B.
  • the insulation resistance value R L is calculated and detected from the first and second current values I 1 and I 2 according to the following equation (2).
  • R L (V 1 ⁇ V 2 ) / (I 1 ⁇ I 2 ) -(R d2 ⁇ I 2 -R d1 ⁇ I 1 ) / (I 1 -I 2 )
  • V L (V 1 ⁇ I 2 -V 2 ⁇ I 1 + I 1 ⁇ I 2 ⁇ (R d2 -R d1 )) / (I 1 -I 2 )
  • the calculated insulation resistance value RL is compared with a preset reference resistance value to determine the ground fault of the solar cell string 12a. Specifically, when the insulation resistance value RL is smaller than the reference resistance value, it is determined that “ground fault exists”, while when the insulation resistance value RL is equal to or greater than the reference resistance value, it is determined that there is no ground fault. .
  • the present embodiment it is possible to accurately detect the ground fault at low cost. Moreover, when detecting a ground fault, a short circuit operation is not required, and safety can be improved. Furthermore, since the occurrence of an accident current is not a prerequisite for ground fault detection, as in the case of ground fault detection by the zero-phase current detection method, for example, the occurrence of the accident current can be suppressed.
  • the MOSFET 40 is used as a semiconductor element that functions as a blocking unit, but the present invention is not limited to this. Instead, it is also preferable to use an IGBT (Insulated Gate Bipolar Transistor) or the like.
  • An IGBT used as a blocking unit is effective when blocking a high voltage and a high current as compared with a MOSFET.
  • an SCR Silicon Controlled Rectifier
  • GTO Gate Turn Off Thyristor
  • the MOSFET, IGBT, SCR, and GTO are made of silicon, but may be made of silicon carbide, which is said to have better switching performance than silicon. Furthermore, in order to increase other switching speeds, it is also possible to use switching elements of compound semiconductors such as gallium arsenide and gallium arsenide aluminum. Further, the above-described failure detection method is an example, and is not limited to that described with reference to FIGS. Other fault detection methods such as ground faults may be used.
  • the configuration in which the backflow prevention diode is used on both the positive electrode side and the negative electrode side has been described.
  • the configuration may be used only on either the positive electrode side or the negative electrode side.
  • the present invention relates to a switching device, a failure detection device, a solar power generation system, and a switching method, and can be used for, for example, a switching device and a method for disconnecting a solar cell in the solar power generation system.
  • Switch element 9 Detection resistor 10 Solar cell module 12, 502 Solar cell string 20, 21, 504 Diode 30, 40, 50 MOSFET 31, 33 Switching device 32, 42, 52 Diode unit 34, 44, 54 Transistor unit 36 Detection unit 38 Control unit 80 Switch unit 81 Grounding circuit 84 Resistance 82 DC power supply 86 Ammeter 100 Switch mechanism 102 Switching device 104 Gate drive circuit 200 Failure detection device 202, 204, 508, 509 Junction box 300, 501 Solar cell array 400, 510 Load device 402, 404, 506 Breaker 500 Solar power generation system 503 Switch

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electromagnetism (AREA)
  • Sustainable Energy (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Sustainable Development (AREA)
  • Photovoltaic Devices (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Power Conversion In General (AREA)

Abstract

The present invention has the objective of providing a device which is capable of electrically disconnecting a solar cell from a solar power system while reducing power required for an opening and closing operation. A switching device (102) according to the present invention is a switching device (102) which performs an opening operation which electrically disconnects, and a closing operation which electrically connects, solar cells (12) with respect to a load device (400) which consumes or converts power generated by the solar cells (12), the solar cells (12) and the load device (400) being connected by wires; wherein the switching device (102) is characterized in being provided with: opening/closing units which are disposed in the middle of the wires, and which perform opening and closing of the wires using MOSFETs (30), the MOSFETs (30) each having a transistor unit (34) which performs switching between a source and a drain, and a diode unit (32) which causes current to flow in a predetermined direction between the source and the drain of the transistor unit; and interruption units which are disposed in a series with the MOSFETs (30) in the middle of the wires, and which each use a MOSFET (40) to interrupt current caused to flow by the respective diode unit (32) of the respective MOSFET (30).

Description

スイッチング装置、故障検知装置、太陽光発電システム、及びスイッチング方法Switching device, failure detection device, solar power generation system, and switching method
　本出願は、２０１３年４月１８に日本国に出願されたＪＰ２０１３－０８７７３０（出願番号）を基礎出願とする優先権を主張する出願である。ＪＰ２０１３－０８７７３０に記載された内容は、本出願にインコーポレートされる。 This application is an application claiming priority based on JP2013-087730 (application number) filed in Japan on April 18, 2013. The contents described in JP2013-087730 are incorporated into the present application.
　本発明は、スイッチング装置、故障検知装置、太陽光発電システム、及びスイッチング方法に係り、例えば、太陽光発電システム内の太陽電池を切り離すためのスイッチング装置および方法に関する。 The present invention relates to a switching device, a failure detection device, a solar power generation system, and a switching method, for example, a switching device and a method for disconnecting a solar cell in the solar power generation system.
　太陽光を利用して発電を行う太陽光発電システムでは、一般的に、複数の太陽電池モジュールが直列および並列に接続されて、大電圧および大電流となった発電された電力が、パワーコンディショナー等の負荷装置に供給され、商用電力系統等に供給される。太陽光発電システムでは、複数の太陽電池モジュールが直列に接続されて太陽電池ストリングが構成される。そして、複数の太陽電池ストリングが並列に接続されて太陽電池アレイが構成される。 In a photovoltaic power generation system that generates power using sunlight, generally, a plurality of solar cell modules are connected in series and in parallel, and the generated power that has become a large voltage and a large current is a power conditioner or the like. Are supplied to a commercial power system and the like. In the photovoltaic power generation system, a plurality of solar cell modules are connected in series to form a solar cell string. A plurality of solar cell strings are connected in parallel to form a solar cell array.
　かかる太陽光発電システムにおいて、太陽電池アレイ内に絶縁不良があると、電気回路が外部と意図しない形で接触する地絡が生じる場合がある。例えば人や物が絶縁不良箇所に触れたときや、絶縁不良箇所と金属架台等とが接触したとき等が挙げられる。地絡以外にも、太陽電池モジュールが内蔵しているバイパスダイオードの故障や、太陽電池セル間の導通不良等の不具合を生じる場合がある。そのため、太陽光発電システム内には、かかる地絡等の故障を検知する装置が配置される（例えば、特許文献１参照）。 In such a solar power generation system, if there is an insulation failure in the solar cell array, a ground fault may occur where the electric circuit comes into contact with the outside in an unintended manner. For example, when a person or an object touches a poorly insulated part, or when a poorly insulated part comes into contact with a metal mount or the like. In addition to ground faults, problems such as failure of a bypass diode built into the solar cell module and poor conduction between solar cells may occur. Therefore, an apparatus for detecting such a fault such as a ground fault is arranged in the solar power generation system (see, for example, Patent Document 1).
　かかる地絡検出等の故障検出を行うためには、検査のために太陽電池ストリングを太陽光発電システムから電気的に切り離すことが有効である。他方、太陽電池ストリングで発電された電力を供給させるためには、太陽電池ストリングを太陽光発電システムに電気的に接続させることが必要となる。よって、太陽電池ストリングを太陽光発電システムに接続および遮断するためのスイッチが必要となる。 In order to perform fault detection such as ground fault detection, it is effective to electrically disconnect the solar cell string from the photovoltaic power generation system for inspection. On the other hand, in order to supply the electric power generated by the solar cell string, it is necessary to electrically connect the solar cell string to the solar power generation system. Therefore, a switch for connecting and disconnecting the solar cell string to the photovoltaic power generation system is required.
　特に、例えば、特開２０１１－０６６３２０に示された太陽電池アレイの診断方法では、診断対象の陽電池ストリングを他の太陽電池ストリングから切り離すことが有効である。また、特開２０１１－００２４１７に示された地絡検出装置においては、太陽電池が大地から絶縁されていることが必要であり、インバータが非絶縁方式である場合には診断対象の太陽電池ストリングをインバータから切り離すことが有効である。 In particular, for example, in the solar cell array diagnosis method disclosed in Japanese Patent Application Laid-Open No. 2011-066632, it is effective to separate the positive cell string to be diagnosed from other solar cell strings. Further, in the ground fault detection device disclosed in Japanese Patent Application Laid-Open No. 2011-002417, it is necessary that the solar cell is insulated from the ground, and when the inverter is a non-insulated system, the solar cell string to be diagnosed is It is effective to disconnect from the inverter.
　さらに、特開２０１１－０６６３２０に示された太陽電池アレイの診断方法において、太陽電池内の直列抵抗上昇を診断するためには、逆流防止ダイオードを経由せずに太陽電池ストリングに電流を流すことが必要であり、このためには検査対象太陽電池ストリングを、逆流防止ダイオードから解列することが有効である。この他、一般に、検査対象太陽電池ストリングがインバータに接続されていると、インバータからのノイズの影響を受けやすいため、検査対象太陽電池ストリングをインバータから解列することが有効である。 Furthermore, in the solar cell array diagnosis method disclosed in Japanese Patent Application Laid-Open No. 2011-066320, in order to diagnose an increase in series resistance in the solar cell, a current is allowed to flow through the solar cell string without going through the backflow prevention diode. For this purpose, it is effective to disconnect the solar cell string to be inspected from the backflow prevention diode. In addition, in general, when the inspection target solar cell string is connected to the inverter, it is easily affected by noise from the inverter. Therefore, it is effective to disconnect the inspection target solar cell string from the inverter.
　図２０は、太陽光発電システムの構成の一部を例示する概念図である。図２０において、複数の太陽電池ストリング５０２が並列に接続されて太陽電池アレイ５０１が構成される。太陽電池アレイ５０１は、遮断器５０６を介して負荷装置５１０に接続され、電力が供給される。各太陽電池ストリング５０２には、正極（＋）側と負極（－）側に、それぞれ遮断器或いは断路器といったスイッチ５０３が接続され、両極のスイッチ５０３を介して複数の太陽電池ストリング５０２が並列に接続される。また、各太陽電池ストリング５０２には、負荷装置５１０や他の太陽電池ストリング５０２からの漏れ電流が当該太陽電池ストリング５０２側に流れないように逆流防止用のダイオード５０４が配置されている。太陽電池ストリング５０２の正極側のスイッチ５０３とダイオード５０４と遮断器５０６は、接続箱５０８内に配置される。太陽電池ストリング５０２の負極側のスイッチ５０３と遮断器５０６は、接続箱５０９内に配置される。実際には、接続箱５０８と接続箱５０９は同一の筐体となる場合が多い。 FIG. 20 is a conceptual diagram illustrating a part of the configuration of the solar power generation system. In FIG. 20, a plurality of solar cell strings 502 are connected in parallel to form a solar cell array 501. The solar cell array 501 is connected to the load device 510 via the circuit breaker 506 and supplied with electric power. Each solar cell string 502 is connected to a positive electrode (+) side and a negative electrode (−) side, respectively, with a switch 503 such as a circuit breaker or a disconnector, and a plurality of solar cell strings 502 are connected in parallel via the bipolar electrode switch 503. Connected. Further, each solar cell string 502 is provided with a backflow preventing diode 504 so that a leakage current from the load device 510 or another solar cell string 502 does not flow to the solar cell string 502 side. The switch 503, the diode 504, and the circuit breaker 506 on the positive electrode side of the solar cell string 502 are disposed in the connection box 508. The switch 503 and the circuit breaker 506 on the negative electrode side of the solar cell string 502 are disposed in the connection box 509. In practice, the connection box 508 and the connection box 509 are often the same casing.
　そして、スイッチ５０３によって太陽光発電システムから電気的に切り離された太陽電池ストリング５０２は、図示しない故障検知装置に接続されることになる。故障検知装置での検知作業後は、特に異常がなければ検知対象となった太陽電池ストリング５０２を自動で太陽光発電システムに戻す必要があるため、スイッチ５０３として自動制御可能なスイッチ装置が求められる。従来、太陽電池ストリング５０２のような直流回路においては、スイッチ５０３として、機械的（メカニカル）なスイッチが利用されていた。しかしながら、機械的スイッチでは、太陽電池ストリング５０２から電流が流れている状態で回路を開（ＯＦＦ）にすると、アークが発生してしまうといった問題があった。アークを防ぐためには大型のリレー等のスイッチ装置を使用する必要があり、回路の開閉に大きな電力が必要となるといった問題があった。また、故障検知を日常的に実施するために、スイッチを日常的にＯＮ／ＯＦＦした場合は、繰り返し動作に対する耐久性の観点からも、機械的スイッチには問題があった。 And the solar cell string 502 electrically disconnected from the photovoltaic power generation system by the switch 503 is connected to a failure detection device (not shown). After the detection operation by the failure detection device, it is necessary to automatically return the solar cell string 502 to be detected to the solar power generation system unless there is an abnormality. Therefore, a switch device that can be automatically controlled is required as the switch 503. . Conventionally, in a DC circuit such as the solar cell string 502, a mechanical switch has been used as the switch 503. However, the mechanical switch has a problem that an arc is generated when the circuit is opened (OFF) in a state where a current flows from the solar cell string 502. In order to prevent the arc, it is necessary to use a switch device such as a large relay, and there is a problem that a large amount of electric power is required to open and close the circuit. In addition, when the switch is turned on / off on a daily basis in order to perform failure detection on a daily basis, there is a problem with the mechanical switch from the viewpoint of durability against repeated operations.
　そこで、機械的スイッチに代わって、半導体スイッチを用いることが検討されている。半導体スイッチを用いることで開閉動作に要する電力を低減させ、繰り返し動作に対する耐久性を向上させることができる。例えば、スイッチ５０３として、ＭＯＳＦＥＴ（Ｍｅｔａｌ　Ｏｘｉｄｅ　Ｓｅｍｉｃｏｎｄｕｃｔｏｒ　Ｆｉｅｌｄ　Ｅｆｆｅｃｔ　Ｔｒａｎｓｉｓｔｏｒ）を用いることが考えられる。しかしながら、太陽電池ストリング５０２と接続する回路のような大電圧および大電流に耐えるＭＯＳＦＥＴには、寄生ダイオードが並列に存在する。そのため、トランジスタ機能によって回路を遮断しても、一方の方向に対して寄生ダイオードによって電流が流れてしまう。そのため、寄生ダイオードの順方向が太陽電池ストリング５０２から電流が流れる向きとは逆になるように配置することになる。一方、地絡等の故障検出では、完全に回路が遮断され、負荷装置５１０や他の太陽電池ストリング５０２からの漏れ電流が入り込まない状態で検査を行うことが望まれる。しかしながら、逆流防止用のダイオード５０４の逆方向抵抗は、電圧によって異なり、一般に低電圧で低抵抗、高電圧で高抵抗となる。よって、逆流防止用のダイオード５０４は、通常システムが発電している際の太陽電池ストリングが破損等する程度の大きさの逆電流を遮断することは十分に可能であるが、小さい漏れ電流に対しての遮断効果は期待できない。そのため、例えば、ＧΩオーダーで絶縁が必要な故障検出では、ダイオード５０４からの漏れ電流が寄生ダイオードを介して流れ込むことになり、地絡検出等においては高精度な検出が困難になるといった問題があった。また通常、逆流防止用ダイオード５０４は、太陽電池の片極（図２０では正極）にしか装着されていないため、負極側からの漏れ電流を防止することは出来ない問題があった。 Therefore, using a semiconductor switch instead of a mechanical switch is being studied. By using a semiconductor switch, power required for opening and closing operations can be reduced, and durability against repeated operations can be improved. For example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) can be used as the switch 503. However, in a MOSFET that can withstand a large voltage and a large current such as a circuit connected to the solar cell string 502, a parasitic diode exists in parallel. Therefore, even if the circuit is interrupted by the transistor function, a current flows through the parasitic diode in one direction. Therefore, it arrange | positions so that the forward direction of a parasitic diode may be reverse to the direction where an electric current flows from the solar cell string 502. FIG. On the other hand, when detecting a fault such as a ground fault, it is desirable to perform an inspection in a state where the circuit is completely interrupted and leakage current from the load device 510 and other solar cell strings 502 does not enter. However, the reverse resistance of the diode 504 for preventing backflow varies depending on the voltage, and generally becomes low resistance at low voltage and high resistance at high voltage. Therefore, the backflow prevention diode 504 can sufficiently cut off a reverse current that is large enough to damage the solar cell string when the system is generating power. No blocking effect can be expected. Therefore, for example, in failure detection that requires insulation on the order of GΩ, a leakage current from the diode 504 flows through the parasitic diode, and there is a problem that high-precision detection is difficult in ground fault detection and the like. It was. Moreover, since the backflow prevention diode 504 is usually attached only to one electrode of the solar cell (positive electrode in FIG. 20), there is a problem that leakage current from the negative electrode side cannot be prevented.
特開２０１３－０３３８２５号公報JP 2013-033825 A
　そこで、本発明は、上述した問題点を克服し、開閉動作に要する電力を低減させながら太陽電池を太陽光発電システムから電気的に切り離すことが可能な装置および方法を提供することを目的とする。 Therefore, the present invention has an object to provide an apparatus and a method that can overcome the above-described problems and can electrically disconnect a solar cell from a photovoltaic power generation system while reducing the power required for opening and closing operations. .
　本発明の一態様のスイッチング装置は、
　配線により接続された、太陽電池と太陽電池により発電された電力を消費又は変換する負荷装置とを電気的に切り離す開動作と接続する閉動作とを行うスイッチング装置であって、
　配線途中に配置され、ソース及びドレイン間のスイッチングを行うトランジスタ部とトランジスタ部のソース及びドレイン間の所定の方向に電流を流すダイオード部とを有する第１の半導体素子を用いて配線の開閉を行う開閉部と、
　配線途中で第１の半導体素子と直列に配置され、第１の半導体素子が有するダイオード部によって流れる電流を遮断する、第２の半導体素子を用いた遮断部と、
　を備えたことを特徴とする。 The switching device of one embodiment of the present invention includes:
A switching device that performs an opening operation that electrically connects a solar cell and a load device that consumes or converts power generated by the solar cell and a closing operation that is connected by wiring,
The wiring is opened and closed using a first semiconductor element that is arranged in the middle of the wiring and has a transistor portion that performs switching between the source and drain and a diode portion that flows current in a predetermined direction between the source and drain of the transistor portion. An opening and closing part;
A blocking unit using the second semiconductor element, which is arranged in series with the first semiconductor element in the middle of the wiring and blocks a current flowing through the diode unit included in the first semiconductor element;
It is provided with.
　また、本発明の一態様の太陽電池の故障検知装置は、
　上述したスイッチング装置と、
　スイッチング装置によって電気的に切り離された太陽電池の故障を検知する検知部と、
　を備えたことを特徴とする。 Moreover, the failure detection device for a solar cell according to an aspect of the present invention includes:
A switching device as described above;
A detection unit for detecting a failure of the solar cell electrically disconnected by the switching device;
It is provided with.
　また、本発明の一態様の太陽光発電システムは、
　複数の太陽電池モジュールを直列に接続した複数の太陽電池ストリングを並列に接続した太陽電池アレイと、
　複数の太陽電池ストリングとそれぞれ配線によって接続され、複数の太陽電池ストリングにより発電された電力を消費又は変換する負荷装置と、
　太陽電池ストリング毎の配線の正極側と負極側の少なくとも一方の途中にそれぞれ配置され、ソース及びドレイン間のスイッチングを行うトランジスタ部とトランジスタ部のソース及びドレイン間の所定の方向に電流を流すダイオード部とを有する第１の半導体素子を用いて配線の前記少なくとも一方の開閉を行う開閉部と、
　太陽電池ストリング毎の配線の上述した少なくとも一方の途中で第１の半導体素子と直列にそれぞれ配置され、第１の半導体素子が有するダイオード部によって流れる電流を遮断する、第２の半導体素子を用いた遮断部と、
　を備えたことを特徴とする。 In addition, the photovoltaic power generation system of one embodiment of the present invention includes:
A solar cell array in which a plurality of solar cell strings in which a plurality of solar cell modules are connected in series are connected in parallel;
A load device that is connected to a plurality of solar cell strings by wiring and that consumes or converts the power generated by the plurality of solar cell strings;
A transistor unit that is arranged in the middle of at least one of the positive electrode side and the negative electrode side of the wiring for each solar cell string, and that conducts current in a predetermined direction between the source and drain of the transistor unit and a transistor unit that performs switching between the source and drain An opening / closing part that opens and closes at least one of the wirings using a first semiconductor element having:
A second semiconductor element that is arranged in series with the first semiconductor element in the middle of at least one of the above-described wirings for each solar cell string and that cuts off a current flowing through a diode portion included in the first semiconductor element is used. A blocking section;
It is provided with.
　また、本発明の一態様のスイッチング方法は、
　配線により接続された、太陽電池と太陽電池により発電された電力を消費又は変換する負荷装置とを電気的に切り離す開動作と接続する閉動作とを行うスイッチング方法であって、
　配線途中に配置され、ソース及びドレイン間のスイッチングを行うトランジスタ部とトランジスタ部のソース及びドレイン間の所定の方向に電流を流すダイオード部とを有する第１の半導体素子を用いて配線の開動作を行い、
　配線途中で第１の半導体素子と直列に配置された第２の半導体素子を用いて、第１の半導体素子によって配線が開に制御された状態において、第１の半導体素子が有するダイオード部によって流れる電流を遮断することを特徴とする。 The switching method of one embodiment of the present invention includes:
A switching method for performing an open operation for electrically disconnecting a solar cell and a load device that consumes or converts the power generated by the solar cell connected by wiring and a close operation for connection,
An opening operation of the wiring is performed using a first semiconductor element that is arranged in the middle of the wiring and has a transistor portion that performs switching between the source and the drain and a diode portion that flows current in a predetermined direction between the source and the drain of the transistor portion. Done
Using the second semiconductor element arranged in series with the first semiconductor element in the middle of the wiring, the first semiconductor element flows in the diode portion of the first semiconductor element in a state where the wiring is controlled to be opened. The current is cut off.
　本発明の一態様によれば、開閉動作に要する電力を低減し、かつ耐久性を維持しながら太陽電池を太陽光発電システムから電気的に切り離すことができる。 According to one embodiment of the present invention, the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation and maintaining the durability.
実施の形態１における太陽光発電システムの構成を示す構成図である。1 is a configuration diagram showing a configuration of a photovoltaic power generation system in Embodiment 1. FIG. 実施の形態１におけるスイッチング装置の内部構成の一例を示す図である。3 is a diagram illustrating an example of an internal configuration of a switching device according to Embodiment 1. FIG. 実施の形態１におけるＭＯＳＦＥＴの一例を示す断面図である。3 is a cross-sectional view showing an example of a MOSFET in the first embodiment. FIG. 実施の形態１の比較例となる太陽電池アレイとスイッチング装置の一例を示す図である。It is a figure which shows an example of the solar cell array and switching apparatus which become a comparative example of Embodiment 1. FIG. 実施の形態１の比較例となる太陽電池アレイとスイッチング装置の他の一例を示す図である。It is a figure which shows another example of the solar cell array and switching device which become a comparative example of Embodiment 1. FIG. 実施の形態１の比較例となる太陽電池アレイとスイッチング装置の他の一例を示す図である。It is a figure which shows another example of the solar cell array and switching device which become a comparative example of Embodiment 1. FIG. 実施の形態１の比較例となる太陽電池アレイとスイッチング装置の他の一例を示す図である。It is a figure which shows another example of the solar cell array and switching device which become a comparative example of Embodiment 1. FIG. 実施の形態２におけるスイッチング装置の内部構成の一例を示す図である。6 is a diagram illustrating an example of an internal configuration of a switching device according to Embodiment 2. FIG. 実施の形態２におけるＭＯＳＦＥＴの外観図の一例である。10 is an example of an external view of a MOSFET in a second embodiment. FIG. 実施の形態３におけるスイッチング装置の内部構成の一例を示す図である。FIG. 10 is a diagram illustrating an example of an internal configuration of a switching device according to a third embodiment. 実施の形態４におけるスイッチング装置の内部構成の一例を示す図である。FIG. 10 is a diagram illustrating an example of an internal configuration of a switching device according to a fourth embodiment. 実施の形態５におけるスイッチング装置の内部構成の一例を示す図である。FIG. 10 is a diagram illustrating an example of an internal configuration of a switching device according to a fifth embodiment. 実施の形態６におけるスイッチング装置の内部構成の一例を示す図である。FIG. 20 is a diagram illustrating an example of an internal configuration of a switching device according to a sixth embodiment. 実施の形態７におけるスイッチング装置の内部構成の一例を示す図である。FIG. 20 is a diagram illustrating an example of an internal configuration of a switching device according to a seventh embodiment. 実施の形態８におけるスイッチング装置の内部構成の一例を示す図である。FIG. 20 is a diagram illustrating an example of an internal configuration of a switching device according to an eighth embodiment. 実施の形態９におけるスイッチング装置の内部構成の一例を示す図である。FIG. 20 is a diagram illustrating an example of an internal configuration of a switching device according to a ninth embodiment. 実施の形態１０における太陽光発電システムの構成の一部を示す構成図である。It is a block diagram which shows a part of structure of the solar energy power generation system in Embodiment 10. FIG. 各実施の形態における検知部の内部構成の一例を示す図である。It is a figure which shows an example of the internal structure of the detection part in each embodiment. 各実施の形態における検知部の内部構成の別の一例を示す図である。It is a figure which shows another example of the internal structure of the detection part in each embodiment. 太陽光発電システムの構成の一部を例示する概念図である。It is a conceptual diagram which illustrates a part of structure of a solar energy power generation system.
　図１は、実施の形態１における太陽光発電システムの構成を示す構成図である。図１において、太陽光発電システム５００は、太陽光エネルギーを利用して発電するシステムである。太陽光発電システム５００は、故障検知装置２００と、太陽電池アレイ３００と、負荷装置４００と、を備えている。電気的に直列に接続された複数の太陽電池モジュール１０ａ～ｄ（太陽電池の一例）によって太陽電池ストリング１２（太陽電池の一例）が構成される。各太陽電池モジュール１０は、太陽光エネルギーを電気エネルギーに変換し、直流電力として出力するモジュールである。そして、太陽電池アレイ３００は、並列に配置された複数の太陽電池ストリング１２ａ～ｄによって構成される。複数の太陽電池ストリング１２ａ～ｄは、故障検知装置２００内部で電気的に並列に接続される。図１の例では、各太陽電池ストリング１２が直列に接続された４つの太陽電池モジュール１０ａ～ｄによって構成されているが、これに限るものではない。直列数は、２つでも、３つでも、或いは５つ以上であってもよい。適宜設定すればよい。同様に、太陽電池アレイ３００は、並列に接続された４つの太陽電池ストリング１２ａ～ｄによって構成されているが、これに限るものではない。並列数は、２つでも、３つでも、或いは５つ以上であってもよい。適宜設定すればよい。 FIG. 1 is a configuration diagram showing the configuration of the photovoltaic power generation system according to the first embodiment. In FIG. 1, a solar power generation system 500 is a system that generates power using solar energy. The solar power generation system 500 includes a failure detection device 200, a solar cell array 300, and a load device 400. A solar cell string 12 (an example of a solar cell) is configured by a plurality of solar cell modules 10a to 10d (an example of a solar cell) electrically connected in series. Each solar cell module 10 is a module that converts solar energy into electrical energy and outputs it as DC power. The solar cell array 300 includes a plurality of solar cell strings 12a to 12d arranged in parallel. The plurality of solar cell strings 12a to 12d are electrically connected in parallel inside the failure detection apparatus 200. In the example of FIG. 1, each solar cell string 12 is configured by four solar cell modules 10a to 10d connected in series, but is not limited to this. The number in series may be two, three, or five or more. What is necessary is just to set suitably. Similarly, the solar cell array 300 includes four solar cell strings 12a to 12d connected in parallel, but is not limited thereto. The number in parallel may be two, three, or five or more. What is necessary is just to set suitably.
　故障検知装置２００内には、スイッチ機構１００と、スイッチング装置３１，３３と、検知部３６と、制御部３８と、ゲートドライブ回路１０４とが配置される。スイッチ機構１００は、複数のスイッチング装置１０２ａ～ｈによって構成される。各スイッチング装置１０２の一方側に、太陽電池ストリング１２の正極（＋）或いは負極（－）が接続される。各スイッチング装置１０２の他方側に、逆流防止ダイオード２０或いは逆流防止ダイオード２１が接続される。逆流防止ダイオード２０，２１は、太陽電池ストリング１２から供給される電流が流れる方向が順方向になるように配置される。スイッチング装置１０２は、太陽電池ストリング１２の両極に配置可能な数が配置される。 In the failure detection device 200, a switch mechanism 100, switching devices 31 and 33, a detection unit 36, a control unit 38, and a gate drive circuit 104 are arranged. The switch mechanism 100 includes a plurality of switching devices 102a to 102h. The positive electrode (+) or the negative electrode (−) of the solar cell string 12 is connected to one side of each switching device 102. A backflow prevention diode 20 or a backflow prevention diode 21 is connected to the other side of each switching device 102. The backflow prevention diodes 20 and 21 are arranged such that the direction in which the current supplied from the solar cell string 12 flows is the forward direction. The number of switching devices 102 that can be arranged at both poles of the solar cell string 12 is arranged.
　図１の例では、スイッチング装置１０２ａの一方側に、太陽電池ストリング１２ａの負極（－）が接続される。スイッチング装置１０２ａの他方側に、逆流防止ダイオード２１ａが接続される。逆流防止ダイオード２１ａは順方向が太陽電池ストリング１２ａの負極（－）に向かう方向になるように配置される。スイッチング装置１０２ｂの一方に、太陽電池ストリング１２ａの正極（＋）が接続される。スイッチング装置１０２ｂの他方に、逆流防止ダイオード２０ａが接続される。逆流防止ダイオード２０ａは順方向が太陽電池ストリング１２ａの正極（＋）に向かう方向とは逆方向になるように配置される。 In the example of FIG. 1, the negative electrode (−) of the solar cell string 12a is connected to one side of the switching device 102a. A backflow prevention diode 21a is connected to the other side of the switching device 102a. The backflow prevention diode 21a is arranged so that the forward direction is directed to the negative electrode (−) of the solar cell string 12a. The positive electrode (+) of the solar cell string 12a is connected to one side of the switching device 102b. A backflow prevention diode 20a is connected to the other side of the switching device 102b. The backflow prevention diode 20a is disposed so that the forward direction is opposite to the direction toward the positive electrode (+) of the solar cell string 12a.
　同様に、スイッチング装置１０２ｃの一方側に、太陽電池ストリング１２ｂの負極（－）が接続される。スイッチング装置１０２ｃの他方側に、逆流防止ダイオード２１ｂが接続される。逆流防止ダイオード２１ｂは順方向が太陽電池ストリング１２ｂの負極（－）に向かう方向になるように配置される。スイッチング装置１０２ｄの一方に、太陽電池ストリング１２ｂの正極（＋）が接続される。スイッチング装置１０２ｄの他方に、逆流防止ダイオード２０ｂが接続される。逆流防止ダイオード２０ｂは順方向が太陽電池ストリング１２ｂの正極（＋）に向かう方向とは逆方向になるように配置される。 Similarly, the negative electrode (−) of the solar cell string 12b is connected to one side of the switching device 102c. A backflow prevention diode 21b is connected to the other side of the switching device 102c. The backflow prevention diode 21b is arranged so that the forward direction is directed to the negative electrode (−) of the solar cell string 12b. The positive electrode (+) of the solar cell string 12b is connected to one side of the switching device 102d. A backflow prevention diode 20b is connected to the other side of the switching device 102d. The backflow prevention diode 20b is disposed so that the forward direction is opposite to the direction toward the positive electrode (+) of the solar cell string 12b.
　同様に、スイッチング装置１０２ｅの一方側に、太陽電池ストリング１２ｃの負極（－）が接続される。スイッチング装置１０２ｅの他方側に、逆流防止ダイオード２１ｃが接続される。逆流防止ダイオード２１ｃは順方向が太陽電池ストリング１２ｃの負極（－）に向かう方向になるように配置される。スイッチング装置１０２ｆの一方に、太陽電池ストリング１２ｃの正極（＋）が接続される。スイッチング装置１０２ｆの他方に、逆流防止ダイオード２０ｃが接続される。逆流防止ダイオード２０ｃは順方向が太陽電池ストリング１２ｃの正極（＋）に向かう方向とは逆方向になるように配置される。 Similarly, the negative electrode (−) of the solar cell string 12c is connected to one side of the switching device 102e. A backflow prevention diode 21c is connected to the other side of the switching device 102e. The backflow prevention diode 21c is arranged so that the forward direction is directed to the negative electrode (−) of the solar cell string 12c. The positive electrode (+) of the solar cell string 12c is connected to one side of the switching device 102f. A backflow prevention diode 20c is connected to the other side of the switching device 102f. The backflow prevention diode 20c is arranged so that the forward direction is opposite to the direction toward the positive electrode (+) of the solar cell string 12c.
　同様に、スイッチング装置１０２ｇの一方側に、太陽電池ストリング１２ｄの負極（－）が接続される。スイッチング装置１０２ｇの他方側に、逆流防止ダイオード２１ｄが接続される。逆流防止ダイオード２１ｄは順方向が太陽電池ストリング１２ｄの負極（－）に向かう方向になるように配置される。スイッチング装置１０２ｈの一方に、太陽電池ストリング１２ｄの正極（＋）が接続される。スイッチング装置１０２ｈの他方に、逆流防止ダイオード２０ｄが接続される。逆流防止ダイオード２０ｄは順方向が太陽電池ストリング１２ｄの正極（＋）に向かう方向とは逆方向になるように配置される。 Similarly, the negative electrode (−) of the solar cell string 12d is connected to one side of the switching device 102g. A backflow prevention diode 21d is connected to the other side of the switching device 102g. The backflow prevention diode 21d is arranged so that the forward direction is directed to the negative electrode (−) of the solar cell string 12d. The positive electrode (+) of the solar cell string 12d is connected to one side of the switching device 102h. A backflow prevention diode 20d is connected to the other side of the switching device 102h. The backflow prevention diode 20d is disposed so that the forward direction is opposite to the direction toward the positive electrode (+) of the solar cell string 12d.
　そして、各逆流防止ダイオード２０ａ～ｄは、並列に遮断器４０２に接続される。各逆流防止ダイオード２１ａ～ｄは、並列に遮断器４０４に接続される。そして、遮断器４０２，４０４は、それぞれ負荷装置４００に接続される。以上のようにして、太陽電池アレイ３００の正極（＋）側は遮断器４０２を介して、負極（－）側は遮断器４０４を介して、それぞれ負荷装置４００に接続される。負荷装置４００は、複数の太陽電池ストリング１２により発電された電力を消費又は変換する。負荷装置４００として、例えば、パワーコンディショナー等が挙げられる。太陽電池アレイ３００から負荷装置４００に供給された直流電力は、負荷装置４００内で例えば三相交流電力等に変換され、例えば、商用電力系統等に供給される。 The backflow prevention diodes 20a to 20d are connected to the circuit breaker 402 in parallel. Each of the backflow prevention diodes 21a to 21d is connected to the circuit breaker 404 in parallel. Circuit breakers 402 and 404 are connected to load device 400, respectively. As described above, the positive electrode (+) side of the solar cell array 300 is connected to the load device 400 via the circuit breaker 402, and the negative electrode (−) side is connected to the load device 400 via the circuit breaker 404. The load device 400 consumes or converts the power generated by the plurality of solar cell strings 12. Examples of the load device 400 include a power conditioner. The DC power supplied from the solar cell array 300 to the load device 400 is converted into, for example, three-phase AC power in the load device 400 and supplied to, for example, a commercial power system.
　各太陽電池ストリング１２の正極（＋）側は、スイッチング装置１０２と並列に分岐して、複数のスイッチで構成されるスイッチング装置３１の対応するスイッチに接続される。各太陽電池ストリング１２の負極（－）側は、スイッチング装置１０２と並列に分岐して、複数のスイッチで構成されるスイッチング装置３３の対応するスイッチに接続される。そして、スイッチング装置３１，３３のそれぞれのスイッチは、検知部３６に接続される。 The positive (+) side of each solar cell string 12 branches in parallel with the switching device 102 and is connected to a corresponding switch of the switching device 31 constituted by a plurality of switches. The negative electrode (−) side of each solar cell string 12 branches in parallel with the switching device 102 and is connected to a corresponding switch of the switching device 33 constituted by a plurality of switches. Each switch of the switching devices 31 and 33 is connected to the detection unit 36.
　そして、検知部３６では、制御部３８による制御に基づいて、後述するように故障検知を行う。故障検知は、太陽電池ストリング１２毎に実施され、故障検知を行う際、制御部３８は、検査対象となる太陽電池ストリング１２の両極に接続されたスイッチング装置１０２が開（ＯＦＦ）となるようにゲートドライブ回路１０４に制御信号を送信する。そして、ゲートドライブ回路１０４は、対応するスイッチング装置１０２が開（ＯＦＦ）となるように制御する。その後、制御部３８は、検査対象となる太陽電池ストリング１２の両極に接続されたスイッチング装置３１，３３が閉（ＯＮ）となるように制御する。かかる動作により、検査対象となる太陽電池ストリング１２が太陽光発電システムから電気的に切り離され、検知部３６に接続されることになる。なお、図１では、便宜上、複数のスイッチング装置１０２が直列にゲートドライブ回路１０４と接続しているように示しているが、各スイッチング装置１０２は、並列にゲートドライブ回路１０４から制御信号を受信する。 Then, the detection unit 36 performs failure detection as will be described later based on the control by the control unit 38. Failure detection is performed for each solar cell string 12, and when performing failure detection, the control unit 38 causes the switching device 102 connected to both poles of the solar cell string 12 to be inspected to be opened (OFF). A control signal is transmitted to the gate drive circuit 104. The gate drive circuit 104 controls the corresponding switching device 102 to be opened (OFF). Thereafter, the control unit 38 controls the switching devices 31 and 33 connected to both poles of the solar cell string 12 to be inspected to be closed (ON). With this operation, the solar cell string 12 to be inspected is electrically disconnected from the solar power generation system and connected to the detection unit 36. In FIG. 1, for convenience, a plurality of switching devices 102 are illustrated as being connected in series to the gate drive circuit 104, but each switching device 102 receives a control signal from the gate drive circuit 104 in parallel. .
　図２は、実施の形態１におけるスイッチング装置の内部構成の一例を示す図である。図２において、スイッチング装置１０２は、２つのＭＯＳＦＥＴ（Ｍｅｔａｌ　Ｏｘｉｄｅ　Ｓｅｍｉｃｏｎｄｕｃｔｏｒ　Ｆｉｅｌｄ　Ｅｆｆｅｃｔ　Ｔｒａｎｓｉｓｔｏｒ）３０，４０を組み合わせて使用する。ＭＯＳＦＥＴ３０（第１の半導体素子）は、ソース及びドレイン間のスイッチングを行うトランジスタ部３４とトランジスタ部３４のソース及びドレイン間の所定の方向に電流を流すダイオード部３２（寄生ダイオード）とを有する。同様に、ＭＯＳＦＥＴ４０（第２の半導体素子）は、ソース及びドレイン間のスイッチングを行うトランジスタ部４４とトランジスタ部４４のソース及びドレイン間の所定の方向に電流を流すダイオード部４２（寄生ダイオード）とを有する。スイッチング装置１０２として、ＭＯＳＦＥＴを用いることで、開閉動作に要する電力を低減させることができる。 FIG. 2 is a diagram illustrating an example of an internal configuration of the switching device according to the first embodiment. In FIG. 2, the switching device 102 uses two MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) 30 and 40 in combination. The MOSFET 30 (first semiconductor element) includes a transistor unit 34 that performs switching between the source and the drain, and a diode unit 32 (parasitic diode) that allows a current to flow in a predetermined direction between the source and the drain of the transistor unit 34. Similarly, the MOSFET 40 (second semiconductor element) includes a transistor unit 44 that performs switching between the source and the drain, and a diode unit 42 (parasitic diode) that flows current in a predetermined direction between the source and the drain of the transistor unit 44. Have. By using a MOSFET as the switching device 102, the power required for the opening / closing operation can be reduced.
　ＭＯＳＦＥＴ３０は、太陽電池ストリング１２と負荷装置４００とを繋ぐ配線途中に配置される。そして、ＭＯＳＦＥＴ３０は、かかる配線の開閉を行う開閉部として機能する。ＭＯＳＦＥＴ４０は、かかる配線途中でＭＯＳＦＥＴ３０と直列に配置される。そして、ＭＯＳＦＥＴ４０は、ＭＯＳＦＥＴ３０が有するダイオード部３２によって流れる電流を遮断する遮断部として機能する。ＭＯＳＦＥＴ３０とＭＯＳＦＥＴ４０は、それぞれが有するダイオード部３２，４２が逆向きになるように直列に接続される。図２の例では、ＭＯＳＦＥＴ３０，４０として、ｎ型エンハンスメント型ＦＥＴを用いる。さらに、ＭＯＳＦＥＴ３０，４０のソース側が向き合うように直列に接続される。ソース同士が接続されることで、ＭＯＳＦＥＴ３０，４０のゲートを同電位にすることができる。実施の形態１では、ＭＯＳＦＥＴ３０，４０を同時駆動する。よって、ＭＯＳＦＥＴ３０，４０のＯＮ／ＯＦＦ動作を１系統のゲート電圧信号によって制御できる。図２では、エンハンスメント型を識別するようにゲート部が点線で示されている。 The MOSFET 30 is arranged in the middle of the wiring connecting the solar cell string 12 and the load device 400. The MOSFET 30 functions as an opening / closing unit that opens and closes the wiring. The MOSFET 40 is arranged in series with the MOSFET 30 in the middle of such wiring. The MOSFET 40 functions as a blocking unit that blocks current flowing through the diode unit 32 included in the MOSFET 30. The MOSFET 30 and the MOSFET 40 are connected in series so that the diode portions 32 and 42 included in the MOSFET 30 and the MOSFET 40 are in opposite directions. In the example of FIG. 2, n-type enhancement type FETs are used as the MOSFETs 30 and 40. Further, the MOSFETs 30 and 40 are connected in series so that the source sides thereof face each other. By connecting the sources to each other, the gates of the MOSFETs 30 and 40 can be set to the same potential. In the first embodiment, MOSFETs 30 and 40 are driven simultaneously. Therefore, the ON / OFF operation of the MOSFETs 30 and 40 can be controlled by one system of gate voltage signals. In FIG. 2, the gate portion is indicated by a dotted line so as to identify the enhancement type.
　各太陽電池ストリング１２ａ～ｃの両極には、同様のスイッチング装置１０２ａ～ｆが接続される。図２では、図１の４つの太陽電池ストリング１２ａ～ｄのうち、太陽電池ストリング１２ｄについての構成について記載を省略している。かかるＭＯＳＦＥＴ３０とＭＯＳＦＥＴ４０によって構成されるスイッチング装置１０２によって、配線により接続された、検査対象の太陽電池ストリング１２（太陽電池）の一方の極と太陽電池ストリング１２により発電された電力を消費又は変換する負荷装置４００の対応する一方の極とを電気的に切り離す開動作（ＯＦＦ）と接続する閉動作（ＯＮ）とを行う。 The same switching devices 102a to 102f are connected to both poles of the solar cell strings 12a to 12c. 2, the description of the configuration of the solar cell string 12d among the four solar cell strings 12a to 12d in FIG. 1 is omitted. A load that consumes or converts the electric power generated by one of the poles of the solar cell string 12 (solar cell) to be inspected and the solar cell string 12 connected by wiring by the switching device 102 configured by the MOSFET 30 and the MOSFET 40. An opening operation (OFF) for electrically disconnecting one corresponding pole of the device 400 and a closing operation (ON) for connection are performed.
　例えば、スイッチング装置１０２ａによって、太陽電池ストリング１２ａの配線の開動作（ＯＦＦ）を行う場合、制御部３８によってスイッチング装置１０２ａ，１０２ｂに対して、ゲートＯＦＦにするための制御信号をゲートドライブ回路１０４に出力する。ゲートドライブ回路１０４では、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０の共通するゲート配線へと印加している正のソース・ゲート間電圧をＯＦＦにする。これにより、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断（ＯＦＦ）する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの負極（－）の電位が、発電中の他の太陽電池ストリング１２ｂ等の負極（－）の電位よりも高電位になっても漏れ電流は遮断できる。このように、ＭＯＳＦＥＴ４０は、ＭＯＳＦＥＴ３０によって配線が開（ＯＦＦ）に制御された状態において、ＭＯＳＦＥＴ３０が有するダイオード部３２によって流れる電流を遮断する。よって、太陽光発電システム５００からの影響は回避できる。 For example, when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 sends a control signal for turning off the gate to the gate drive circuit 104 to the switching devices 102a and 102b. Output. In the gate drive circuit 104, the positive source-gate voltage applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102a is turned off. Thereby, both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off (OFF) between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode (−) of the solar cell string 12a is assumed to be negative ( The leakage current can be cut off even when the potential becomes higher than the potential of-). As described above, the MOSFET 40 blocks the current flowing through the diode unit 32 included in the MOSFET 30 in a state where the wiring is controlled to be opened (OFF) by the MOSFET 30. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　同様に、ゲートドライブ回路１０４では、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０の共通するゲート配線へと印加している正のソース・ゲート間電圧をＯＦＦにする。これにより、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断（ＯＦＦ）する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの正極（＋）の電位が、発電中の他の太陽電池ストリング１２ｂ等の正極（＋）の電位よりも低電位になっても漏れ電流は遮断できる。このように、ＭＯＳＦＥＴ４０は、ＭＯＳＦＥＴ３０によって配線が開（ＯＦＦ）に制御された状態において、負極側と同様、ＭＯＳＦＥＴ３０が有するダイオード部３２によって流れる電流を遮断する。よって、太陽光発電システム５００からの影響は回避できる。 Similarly, in the gate drive circuit 104, the positive source-gate voltage applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102b is turned off. As a result, both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off (OFF) between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. As described above, the MOSFET 40 blocks the current flowing through the diode portion 32 included in the MOSFET 30 in the state where the wiring is controlled to be opened (OFF) by the MOSFET 30 as in the case of the negative electrode side. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　なお、スイッチング装置１０２ａ，１０２ｂへと印加しているソース・ゲート間電圧をＯＦＦにするタイミングは、同時が望ましいが、ずれても構わない。そして、スイッチング装置１０２ａ，１０２ｂが共にＯＦＦになり、太陽電池ストリング１２ａが、他の太陽電池ストリング１２ｂ等や負荷装置４００と電気的に切り離された後、制御部３８の制御の基、スイッチング装置３１，３３のうち、太陽電池ストリング１２ａに対応する各スイッチをＯＮ（閉）にする。これにより、太陽電池ストリング１２ａを検知部３６に接続することができる。また、検知部３６に他の太陽電池ストリング１２ｂ等や負荷装置４００からの電流等の入流を回避できる。逆に故障検知動作後は、異常がなければ、太陽電池ストリング１２ａが、他の太陽電池ストリング１２ｂ等や負荷装置４００と電気的につなげることになる。かかる場合には、まず、制御部３８の制御の基、スイッチング装置３１，３３のうち、太陽電池ストリング１２ａに対応する各スイッチをＯＦＦ（開）にする。その後、スイッチング装置１０２ａ，１０２ｂへソース・ゲート間電圧を印加すればよい。これにより、太陽電池ストリング１２ａを発電システムに復帰させることができる。なお、他の太陽電池ストリング１２ｂ等用のスイッチング装置１０２ｃ，ｄ等の開閉動作についても、太陽電池ストリング１２ａと同様である。 Note that the timing for turning off the source-gate voltage applied to the switching devices 102a and 102b is preferably the same, but may be shifted. Then, after both the switching devices 102a and 102b are turned off and the solar cell string 12a is electrically disconnected from the other solar cell strings 12b and the load device 400, the control unit 38 controls the switching device 31. , 33, each switch corresponding to the solar cell string 12a is turned on (closed). Thereby, the solar cell string 12a can be connected to the detector 36. Further, inflow of current from the other solar cell strings 12b and the load device 400 to the detection unit 36 can be avoided. Conversely, after the failure detection operation, if there is no abnormality, the solar cell string 12a is electrically connected to the other solar cell string 12b and the load device 400. In such a case, first, the switches corresponding to the solar cell string 12a among the switching devices 31 and 33 based on the control of the control unit 38 are turned off (opened). Thereafter, a source-gate voltage may be applied to the switching devices 102a and 102b. Thereby, the solar cell string 12a can be returned to the power generation system. The opening / closing operations of the switching devices 102c, d, etc. for the other solar cell strings 12b are the same as those of the solar cell string 12a.
　図３は、実施の形態１におけるＭＯＳＦＥＴの一例を示す断面図である。太陽電池ストリングからは、例えば、数１００Ｖの大電圧が生じる。例えば、５００Ｖ程度の電圧が生じる。また、数Ａ或いは数１０Ａの大電流が流れる。例えば、１０Ａの電流が流れる。実施の形態１では、かかる大電圧および大電流の負荷に耐えるＭＯＳＦＥＴを用いる。そのためには、パワー半導体素子である、例えば、縦型のＭＯＳＦＥＴを用いると好適である。図３では、例えば、ｎ型の縦型ＭＯＳＦＥＴの断面の一例が示されている。図３の例では、ｎ型半導体基板にｐウェルを形成し、ｐウェル内にｎウェルを形成した構成になっている。そして、ｎウェルとｎ型半導体基板との間のｐウェル上にゲート（Ｇ）が形成されている。また、ソース（Ｓ）電極は、ゲートとは反対側のｐウェルに跨るようにｎウェル上に形成される。ドレイン（Ｄ）電極は、ｎ型半導体基板の裏面に形成される。かかるゲート（Ｇ）とソース（Ｓ）とドレイン（Ｄ）によってトランジスタ部が形成される。通常、ゲート（Ｇ）にソース・ゲート間電圧を印加すると、ソース（Ｓ）とドレイン（Ｄ）間のｐウェルにｎチャネルが形成されることで、ソース（Ｓ）とドレイン（Ｄ）間に電流が流れることになる。逆に、ゲート（Ｇ）にソース・ゲート間電圧を印加しなければ、ソース（Ｓ）とドレイン（Ｄ）間に電流が流れないことになる。しかしながら、図３に示す構造のように、ソース（Ｓ）側の電極がｐウェルにも接続する場合、ソース（Ｓ）とドレイン（Ｄ）間にＰＮ接合が存在する。そのため、図３の例では、かかるＰＮ接合部が、ソース（Ｓ）からドレイン（Ｄ）に向かう方向が順方向となる寄生ダイオードとなってしまう。 FIG. 3 is a cross-sectional view showing an example of the MOSFET according to the first embodiment. For example, a large voltage of several hundred volts is generated from the solar cell string. For example, a voltage of about 500V is generated. Further, a large current of several A or several 10 A flows. For example, a current of 10 A flows. In the first embodiment, a MOSFET that can withstand such a large voltage and large current load is used. For this purpose, it is preferable to use, for example, a vertical MOSFET, which is a power semiconductor element. In FIG. 3, for example, an example of a cross section of an n-type vertical MOSFET is shown. In the example of FIG. 3, a p-well is formed in an n-type semiconductor substrate, and an n-well is formed in the p-well. A gate (G) is formed on the p-well between the n-well and the n-type semiconductor substrate. The source (S) electrode is formed on the n-well so as to straddle the p-well opposite to the gate. The drain (D) electrode is formed on the back surface of the n-type semiconductor substrate. A transistor portion is formed by the gate (G), the source (S), and the drain (D). Normally, when a source-gate voltage is applied to the gate (G), an n-channel is formed in the p-well between the source (S) and the drain (D), so that the source (S) and the drain (D) are connected. Current will flow. Conversely, if no source-gate voltage is applied to the gate (G), no current flows between the source (S) and the drain (D). However, when the source (S) side electrode is also connected to the p-well as in the structure shown in FIG. 3, a PN junction exists between the source (S) and the drain (D). Therefore, in the example of FIG. 3, such a PN junction becomes a parasitic diode in which the direction from the source (S) to the drain (D) is the forward direction.
　よって、スイッチング装置１０２に、１つのＭＯＳＦＥＴだけが配置された場合、上述したように、ＭＯＳＦＥＴのトランジスタ機能によって回路を遮断しても、一方の方向に対して寄生ダイオードによって電流が流れてしまう。また、寄生ダイオードの順方向が太陽電池ストリング１２から電流が流れる向きとは逆になるように配置しても、上述したように、逆流防止用のダイオード２０，２１の漏れ電流に対しての遮断効果は期待できない。図３では、一例として、縦型ＭＯＳＦＥＴを示したが、寄生ダイオードが存在するのであれば、横型であっても同様の問題が生じる。以下、実施の形態１の比較例として、故障検知対象の太陽電池ストリング１２ａの両極をそれぞれ１つずつのＭＯＳＦＥＴによってスイッチ動作を行う場合の問題点について以下、説明する。 Therefore, when only one MOSFET is arranged in the switching device 102, as described above, even if the circuit is interrupted by the transistor function of the MOSFET, a current flows through the parasitic diode in one direction. Further, even if the forward direction of the parasitic diode is arranged so as to be opposite to the direction in which the current flows from the solar cell string 12, as described above, the leakage current of the diodes 20 and 21 for preventing the backflow is blocked. The effect cannot be expected. In FIG. 3, a vertical MOSFET is shown as an example. However, if a parasitic diode exists, the same problem occurs even in a horizontal type. Hereinafter, as a comparative example of the first embodiment, a problem in the case where the switching operation is performed by using one MOSFET for each of the two poles of the failure detection target solar cell string 12a will be described below.
　図４は、実施の形態１の比較例となる太陽電池アレイとスイッチング装置の一例を示す図である。図４の例では、故障検知対象の太陽電池ストリング１２ａの両極をそれぞれ１つずつのＭＯＳＦＥＴ５０によってスイッチ動作を行う場合を示している。ＭＯＳＦＥＴ５０には、トランジスタ部５４と上述した寄生ダイオードとなるダイオード部５２とを有する。両極のＭＯＳＦＥＴ５０は、ダイオード部５２の順方向が太陽電池ストリング１２から電流が流れる向きとは逆になるように配置されている。また、太陽電池ストリング１２ａの両極には、同様に、順方向が太陽電池ストリング１２から電流が流れる向きとは逆になるように逆流防止用のダイオード２０，２１が配置されている。図４の例では、故障検知対象の太陽電池ストリング１２ａは、その両極に接続されたＭＯＳＦＥＴ５４がＯＦＦとなり、負荷および他の太陽電池ストリングから解列され、その結果、故障検知対象の太陽電池ストリング１２ａの正極（＋）側の電位が、他の太陽電池ストリングの正極（＋）側の電位よりも高く、故障検知対象の太陽電池ストリング１２ａの負極（－）側の電位が、他の太陽電池ストリングの負極（－）側の電位よりも低い場合を示している。かかる場合、検査対象の太陽電池ストリングの正極（＋）が、発電中の他の太陽電池ストリングの正極（＋）より、高電位であれば、寄生ダイオードがあっても、発電中のシステムから電流は流れないので影響を受けない。同様に、検査対象の太陽電池ストリングの負極が、発電中の太陽電池ストリングの負極より、低電位であれば、寄生ダイオードがあっても、発電中のシステムへと電流は流れないので影響を受けない。 FIG. 4 is a diagram illustrating an example of a solar cell array and a switching device, which is a comparative example of the first embodiment. In the example of FIG. 4, a case is shown where both poles of the solar cell string 12 a to be detected are switched by one MOSFET 50. The MOSFET 50 includes a transistor portion 54 and a diode portion 52 that serves as the parasitic diode described above. The bipolar MOSFETs 50 are arranged such that the forward direction of the diode part 52 is opposite to the direction in which current flows from the solar cell string 12. Similarly, reverse current preventing diodes 20 and 21 are arranged at both poles of the solar cell string 12a so that the forward direction is opposite to the direction in which current flows from the solar cell string 12. In the example of FIG. 4, the failure detection target solar cell string 12 a is disconnected from the load and other solar cell strings because the MOSFETs 54 connected to both poles thereof are OFF, and as a result, the failure detection target solar cell string 12 a. The potential on the positive electrode (+) side of the solar cell string is higher than the potential on the positive electrode (+) side of the other solar cell strings, and the potential on the negative electrode (−) side of the solar cell string 12a to be detected is the other solar cell string. In this case, the potential is lower than the potential on the negative electrode (−) side. In such a case, if the positive electrode (+) of the solar cell string to be inspected has a higher potential than the positive electrodes (+) of other solar cell strings that are generating power, the current from the system that is generating power even if there is a parasitic diode Is not affected because it does not flow. Similarly, if the negative electrode of the solar cell string to be inspected is at a lower potential than the negative electrode of the solar cell string during power generation, even if there is a parasitic diode, current will not flow to the system during power generation, so it will be affected. Absent.
　図５は、実施の形態１の比較例となる太陽電池アレイとスイッチング装置の他の一例を示す図である。図５の例では、故障検知対象の太陽電池ストリング１２ａの正極（＋）側の電位が、他の太陽電池ストリングの正極（＋）側の電位よりも高く、故障検知対象の太陽電池ストリング１２ａの負極（－）側の電位が、故障検出装置（例を後述する）の働きにより、他の太陽電池ストリングの負極（－）側の電位よりも高い場合を示している。その他の構成は、図４と同様である。かかる場合、検査対象の太陽電池ストリングの正極（＋）側は、図４と同様、発電中のシステムから影響を受けない。しかしながら、検査対象の太陽電池ストリングの負極が、発電中の太陽電池ストリングの負極より、高電位であると、寄生ダイオードによって発電中のシステムへと電流が流れてしまうので影響を受ける。かかる影響はブロッキングダイオード２１によってある程度回避できるが、逆方向電流を完全に遮断できないため、回避は不完全である。 FIG. 5 is a diagram showing another example of the solar cell array and the switching device, which is a comparative example of the first embodiment. In the example of FIG. 5, the potential on the positive electrode (+) side of the failure detection target solar cell string 12a is higher than the potential on the positive electrode (+) side of the other solar cell strings, and the failure detection target solar cell string 12a This shows a case where the potential on the negative electrode (−) side is higher than the potential on the negative electrode (−) side of other solar cell strings due to the action of a failure detection device (an example will be described later). Other configurations are the same as those in FIG. In this case, the positive electrode (+) side of the solar cell string to be inspected is not affected by the system during power generation, as in FIG. However, if the negative electrode of the solar cell string to be inspected is at a higher potential than the negative electrode of the solar cell string being generated, the parasitic diode causes a current to flow to the generating system, which is affected. Such an influence can be avoided to some extent by the blocking diode 21, but the avoidance is incomplete because the reverse current cannot be completely blocked.
　図６は、実施の形態１の比較例となる太陽電池アレイとスイッチング装置の他の一例を示す図である。図６の例では、故障検知対象の太陽電池ストリング１２ａの正極（＋）側の電位が、故障検出装置（例を後述する）の働きにより、他の太陽電池ストリングの正極（＋）側の電位よりも低く、故障検知対象の太陽電池ストリング１２ａの負極（－）側の電位が、他の太陽電池ストリングの負極（－）側の電位よりも低い場合を示している。その他の構成は、図４と同様である。かかる場合、故障検知対象の太陽電池ストリング１２ａの負極（－）側は、図４で説明したように、発電中のシステムから影響を受けない。しかしながら、故障検知対象の太陽電池ストリング１２ａの正極（＋）が、発電中ストリングの正極より、低電位であると、寄生ダイオードによって発電中のシステムから電流が流れてしまうので発電中のシステムから影響を受ける。この影響はブロッキングダイオード２０によってある程度回避できるが、逆方向電流を完全に遮断できないため、回避は不完全である。 FIG. 6 is a diagram illustrating another example of a solar cell array and a switching device, which are comparative examples of the first embodiment. In the example of FIG. 6, the potential on the positive electrode (+) side of the failure detection target solar cell string 12 a is the potential on the positive electrode (+) side of another solar cell string due to the action of a failure detection device (an example will be described later). It shows a case where the potential on the negative electrode (−) side of the failure detection target solar cell string 12a is lower than the potential on the negative electrode (−) side of the other solar cell strings. Other configurations are the same as those in FIG. In such a case, the negative electrode (−) side of the failure detection target solar cell string 12a is not affected by the system during power generation, as described with reference to FIG. However, if the positive electrode (+) of the solar cell string 12a subject to failure detection is at a lower potential than the positive electrode of the power generation string, the parasitic diode causes a current to flow from the system that is generating power. Receive. This effect can be avoided to some extent by the blocking diode 20, but the avoidance is incomplete because the reverse current cannot be completely blocked.
　図７は、実施の形態１の比較例となる太陽電池アレイとスイッチング装置の他の一例を示す図である。図７の例では、故障検知対象の太陽電池ストリング１２ａの正極（＋）側の電位が、故障検出装置（例を後述する）の働きにより、他の太陽電池ストリングの正極（＋）側の電位よりも低く、故障検知対象の太陽電池ストリング１２ａの負極（－）側の電位が、故障検出装置（例を後述する）の働きにより、他の太陽電池ストリングの負極（－）側の電位よりも高い場合を示している。その他の構成は、図４と同様である。かかる場合、故障検知対象の太陽電池ストリング１２ａの正極（＋）が、発電中ストリングの正極より、低電位であると、図６で説明したように、寄生ダイオードによって発電中のシステムから電流が流れてしまうので発電中のシステムから影響を受ける。この影響はブロッキングダイオード２０によってある程度回避できるが、逆方向電流を完全に遮断できないため、回避は不完全である。そして、検査対象の太陽電池ストリングの負極が、発電中の太陽電池ストリングの負極より、高電位であると、図５で説明したように、寄生ダイオードによって発電中のシステムへと電流が流れてしまうので影響を受ける。かかる影響はブロッキングダイオード２１によってある程度回避できるが、逆方向電流を完全に遮断できないため、回避は不完全である。 FIG. 7 is a diagram illustrating another example of the solar cell array and the switching device, which are comparative examples of the first embodiment. In the example of FIG. 7, the potential on the positive electrode (+) side of the failure detection target solar cell string 12 a is the potential on the positive electrode (+) side of another solar cell string due to the action of a failure detection device (an example will be described later). The potential on the negative electrode (−) side of the failure detection target solar cell string 12a is lower than the potential on the negative electrode (−) side of other solar cell strings due to the action of the failure detection device (example will be described later). It shows a high case. Other configurations are the same as those in FIG. In such a case, if the positive electrode (+) of the solar cell string 12a to be detected has a lower potential than the positive electrode of the power generation string, current flows from the system that is generating power due to the parasitic diode as described with reference to FIG. Therefore, it is affected by the power generation system. This effect can be avoided to some extent by the blocking diode 20, but the avoidance is incomplete because the reverse current cannot be completely blocked. If the negative electrode of the solar cell string to be inspected has a higher potential than the negative electrode of the solar cell string during power generation, current will flow to the system during power generation due to the parasitic diode as described with reference to FIG. So affected. Such an influence can be avoided to some extent by the blocking diode 21, but the avoidance is incomplete because the reverse current cannot be completely blocked.
　そこで、実施の形態１では、図２に示したように、２つのＭＯＳＦＥＴ３０とＭＯＳＦＥＴ４０のそれぞれが有するダイオード部３２，４２が逆向きになるように直列に接続させる。これにより、寄生ダイオードによる問題を回避できる。 Therefore, in the first embodiment, as shown in FIG. 2, the diode parts 32 and 42 included in the two MOSFETs 30 and 40 are connected in series so as to be opposite to each other. Thereby, the problem by a parasitic diode can be avoided.
　以上のように、実施の形態１によれば、開閉動作に要する電力を低減し、かつ耐久性を維持しながら太陽電池を太陽光発電システムから電気的に切り離すことができる。よって、高精度な地絡検出等が可能になる。 As described above, according to Embodiment 1, the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the electric power required for the opening / closing operation and maintaining the durability. Therefore, it is possible to detect ground faults with high accuracy.
　実施の形態１では、ＭＯＳＦＥＴ３０，４０として、ｎ型エンハンスメント型ＦＥＴのソース同士を接続した場合について示したが、これに限るものではない。実施の形態２では、その他の接続方法について説明する。実施の形態２における太陽光発電システム５００の構成は、図１と同様である。また、以下、特に説明する点以外の内容は、実施の形態１と同様である。 In the first embodiment, the case where the sources of n-type enhancement type FETs are connected as the MOSFETs 30 and 40 is shown, but the present invention is not limited to this. In the second embodiment, other connection methods will be described. The configuration of the photovoltaic power generation system 500 in the second embodiment is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
　図８は、実施の形態２におけるスイッチング装置の内部構成の一例を示す図である。図８において、ＭＯＳＦＥＴ３０，４０として、図２と同様に、ｎ型エンハンスメント型ＦＥＴを用いる。但し、図８では、ＭＯＳＦＥＴ３０，４０のドレイン側が向き合うように直列に接続される。ドレイン同士が接続される場合には、ソース・ゲート間電圧に必要な電位が異なるので、ＭＯＳＦＥＴ３０，４０のゲートへのゲートドライブ回路１０４からの信号線を別に設けるとよい。言い換えれば、実施の形態２では、ＭＯＳＦＥＴ３０，４０を同時駆動するが、ＭＯＳＦＥＴ３０，４０のＯＮ／ＯＦＦ動作を２系統のゲート電圧信号によって制御する。その他の構成は、図２と同様である。 FIG. 8 is a diagram illustrating an example of an internal configuration of the switching device according to the second embodiment. In FIG. 8, n-type enhancement type FETs are used as the MOSFETs 30 and 40 as in FIG. However, in FIG. 8, they are connected in series so that the drain sides of the MOSFETs 30 and 40 face each other. When the drains are connected to each other, the potential required for the source-gate voltage is different. Therefore, it is preferable to provide a separate signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40. In other words, in the second embodiment, the MOSFETs 30 and 40 are driven simultaneously, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by the two gate voltage signals. Other configurations are the same as those in FIG.
　図９は、実施の形態２におけるＭＯＳＦＥＴの外観図の一例である。図９において、ＭＯＳＦＥＴ６０の外側には、放熱板６２が配置される。そして、かかる放熱板６２は、ドレインに接続されている。よって、ドレイン同士が接続される場合、ＭＯＳＦＥＴ３０，４０の放熱板を配置する際に、放熱板同士の絶縁に注意を払う必要が無く、さらに共通化し大型の放熱板を使用することもできるため、デバイスの熱設計が容易になる。 FIG. 9 is an example of an external view of the MOSFET in the second embodiment. In FIG. 9, a heat radiating plate 62 is disposed outside the MOSFET 60. The heat radiating plate 62 is connected to the drain. Therefore, when the drains are connected, there is no need to pay attention to the insulation between the heat sinks when arranging the heat sinks of the MOSFETs 30 and 40, and a common and large heat sink can be used. The thermal design of the device becomes easy.
　図８において、例えば、スイッチング装置１０２ａによって、太陽電池ストリング１２ａの配線の開動作（ＯＦＦ）を行う場合、制御部３８によってスイッチング装置１０２ａ，１０２ｂに対して、ゲートＯＦＦにするための制御信号をゲートドライブ回路１０４に出力する。ゲートドライブ回路１０４では、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０のそれぞれのゲート配線へと印加している正のソース・ゲート間電圧をＯＦＦにする。これにより、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの負極（－）の電位が、発電中の他の太陽電池ストリング１２ｂ等の負極（－）の電位よりも高電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 In FIG. 8, for example, when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104. In the gate drive circuit 104, the positive source-gate voltage applied to the respective gate wirings of the MOSFETs 30 and 40 of the switching device 102a is turned off. As a result, both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode (−) of the solar cell string 12a is assumed to be negative ( The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　同様に、ゲートドライブ回路１０４では、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０のそれぞれのゲート配線へと印加している正のソース・ゲート間電圧をＯＦＦにする。これにより、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの正極（＋）の電位が、発電中の他の太陽電池ストリング１２ｂ等の正極（＋）の電位よりも低電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 Similarly, in the gate drive circuit 104, the positive source-gate voltage applied to the respective gate wirings of the MOSFETs 30 and 40 of the switching device 102b is turned off. As a result, both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　以上のように、実施の形態２によれば、実施の形態１と同様、開閉動作に要する電力を低減させながら太陽電池を太陽光発電システムから電気的に切り離すことができる。 As described above, according to the second embodiment, as in the first embodiment, the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
　実施の形態１では、ＭＯＳＦＥＴ３０，４０として、ｎ型エンハンスメント型ＦＥＴを用いたが、これに限るものではない。実施の形態３では、その他のＭＯＳＦＥＴを用いる場合について説明する。実施の形態３における太陽光発電システム５００の構成は、図１と同様である。また、以下、特に説明する点以外の内容は、実施の形態１と同様である。 In the first embodiment, n-type enhancement type FETs are used as the MOSFETs 30 and 40. However, the present invention is not limited to this. In the third embodiment, a case where another MOSFET is used will be described. The configuration of photovoltaic power generation system 500 in Embodiment 3 is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
　図１０は、実施の形態３におけるスイッチング装置の内部構成の一例を示す図である。図１０において、ＭＯＳＦＥＴ３０，４０として、ｐ型エンハンスメント型ＦＥＴを用いる。そのため、ソース・ゲート間電圧の極性が実施の形態１の場合と逆になる。その他の構成は、図２と同様である。すなわち、図１０では、ＭＯＳＦＥＴ３０，４０のソース側が向き合うように直列に接続されており、このため、ソース・ゲート間電圧を同電位にできるので、ＭＯＳＦＥＴ３０，４０のゲートへのゲートドライブ回路１０４からの信号線を共通にできる。言い換えれば、実施の形態３では、ＭＯＳＦＥＴ３０，４０を同時駆動するが、ＭＯＳＦＥＴ３０，４０のＯＮ／ＯＦＦ動作を１系統のゲート電圧信号によって制御する。 FIG. 10 is a diagram illustrating an example of an internal configuration of the switching device according to the third embodiment. In FIG. 10, p-type enhancement type FETs are used as the MOSFETs 30 and 40. Therefore, the polarity of the source-gate voltage is opposite to that in the first embodiment. Other configurations are the same as those in FIG. That is, in FIG. 10, the source sides of the MOSFETs 30 and 40 are connected in series so as to face each other, so that the source-gate voltage can be made the same potential, so that the gate drive circuit 104 from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40 A signal line can be shared. In other words, in the third embodiment, the MOSFETs 30 and 40 are driven simultaneously, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by one system gate voltage signal.
　図１０において、例えば、スイッチング装置１０２ａによって、太陽電池ストリング１２ａの配線の開動作（ＯＦＦ）を行う場合、制御部３８によってスイッチング装置１０２ａ，１０２ｂに対して、ゲートＯＦＦにするための制御信号をゲートドライブ回路１０４に出力する。ゲートドライブ回路１０４では、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０の共通するゲート配線へと印加している負のソース・ゲート間電圧をＯＦＦにする。これにより、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの負極（－）の電位が、発電中の他の太陽電池ストリング１２ｂ等の負極（－）の電位よりも高電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 In FIG. 10, for example, when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104. In the gate drive circuit 104, the negative source-gate voltage applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102a is turned off. As a result, both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode (−) of the solar cell string 12a is assumed to be negative ( The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　同様に、ゲートドライブ回路１０４では、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０の共通するゲート配線へと印加している負のソース・ゲート間電圧をＯＦＦにする。これにより、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの正極（＋）の電位が、発電中の他の太陽電池ストリング１２ｂ等の正極（＋）の電位よりも低電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 Similarly, in the gate drive circuit 104, the negative source-gate voltage applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102b is turned off. As a result, both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 interrupt the source and drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　以上のように、実施の形態３によれば、実施の形態１と同様、開閉動作に要する電力を低減させながら太陽電池を太陽光発電システムから電気的に切り離すことができる。 As described above, according to the third embodiment, as in the first embodiment, the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
　実施の形態３では、ＭＯＳＦＥＴ３０，４０として、ｐ型エンハンスメント型ＦＥＴのソース同士を接続した場合について示したが、これに限るものではない。実施の形態４では、その他の接続方法について説明する。実施の形態４における太陽光発電システム５００の構成は、図１と同様である。また、以下、特に説明する点以外の内容は、実施の形態１と同様である。 In the third embodiment, the case where the sources of the p-type enhancement FETs are connected as the MOSFETs 30 and 40 has been described, but the present invention is not limited to this. In the fourth embodiment, other connection methods will be described. The configuration of the photovoltaic power generation system 500 in Embodiment 4 is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
　図１１は、実施の形態４におけるスイッチング装置の内部構成の一例を示す図である。図１１において、ＭＯＳＦＥＴ３０，４０として、図１０と同様に、ｐ型エンハンスメント型ＦＥＴを用いる。但し、図１１では、ＭＯＳＦＥＴ３０，４０のドレイン側が向き合うように直列に接続される。ドレイン同士が接続される場合には、ソース・ゲート間電圧に必要な電位が異なるので、ＭＯＳＦＥＴ３０，４０のゲートへのゲートドライブ回路１０４からの信号線を別に設けるとよい。言い換えれば、実施の形態４では、ＭＯＳＦＥＴ３０，４０を同時駆動するが、ＭＯＳＦＥＴ３０，４０のＯＮ／ＯＦＦ動作を２系統のゲート電圧信号によって制御する。その他の構成は、図２と同様である。 FIG. 11 is a diagram illustrating an example of the internal configuration of the switching device according to the fourth embodiment. 11, p-type enhancement type FETs are used as the MOSFETs 30 and 40 in the same manner as in FIG. However, in FIG. 11, the MOSFETs 30 and 40 are connected in series so that the drain sides face each other. When the drains are connected to each other, the potential required for the source-gate voltage is different. Therefore, it is preferable to provide a separate signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40. In other words, in the fourth embodiment, the MOSFETs 30 and 40 are simultaneously driven, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by the two systems of gate voltage signals. Other configurations are the same as those in FIG.
　また、図９で説明したように、ドレイン同士が接続される場合、ＭＯＳＦＥＴ３０，４０の放熱板同士を接続できるので、素子の放熱性を向上させることができる。 As described with reference to FIG. 9, when the drains are connected to each other, the heat dissipation plates of the MOSFETs 30 and 40 can be connected to each other, so that the heat dissipation of the element can be improved.
　図１１において、例えば、スイッチング装置１０２ａによって、太陽電池ストリング１２ａの配線の開動作（ＯＦＦ）を行う場合、制御部３８によってスイッチング装置１０２ａ，１０２ｂに対して、ゲートＯＦＦにするための制御信号をゲートドライブ回路１０４に出力する。ゲートドライブ回路１０４では、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０のそれぞれのゲート配線へと印加している負のソース・ゲート間電圧をＯＦＦにする。これにより、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの負極（－）の電位が、発電中の他の太陽電池ストリング１２ｂ等の負極（－）の電位よりも高電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 In FIG. 11, for example, when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104. In the gate drive circuit 104, the negative source-gate voltage applied to the respective gate wirings of the MOSFETs 30 and 40 of the switching device 102a is turned off. As a result, both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode (−) of the solar cell string 12a is assumed to be negative ( The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　同様に、ゲートドライブ回路１０４では、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０のそれぞれのゲート配線へと印加している負のソース・ゲート間電圧をＯＦＦにする。これにより、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの正極（＋）の電位が、発電中の他の太陽電池ストリング１２ｂ等の正極（＋）の電位よりも低電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 Similarly, in the gate drive circuit 104, the negative source-gate voltage applied to the respective gate wirings of the MOSFETs 30 and 40 of the switching device 102b is turned off. As a result, both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　以上のように、実施の形態４によれば、実施の形態１と同様、開閉動作に要する電力を低減させながら太陽電池を太陽光発電システムから電気的に切り離すことができる。 As described above, according to the fourth embodiment, as in the first embodiment, the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
　実施の形態１では、ＭＯＳＦＥＴ３０，４０として、ｎ型エンハンスメント型ＦＥＴを用いたが、これに限るものではない。実施の形態５では、その他のＭＯＳＦＥＴを用いる場合について説明する。実施の形態５における太陽光発電システム５００の構成は、図１と同様である。また、以下、特に説明する点以外の内容は、実施の形態１と同様である。 In the first embodiment, n-type enhancement type FETs are used as the MOSFETs 30 and 40. However, the present invention is not limited to this. In the fifth embodiment, a case where another MOSFET is used will be described. The configuration of the photovoltaic power generation system 500 in the fifth embodiment is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
　図１２は、実施の形態５におけるスイッチング装置の内部構成の一例を示す図である。図１２において、ＭＯＳＦＥＴ３０，４０として、ｎ型デプレション型ＦＥＴを用いる。そのため、ＯＦＦ動作時において、ソース・ゲート間電圧を印加する。この時、印加電圧は、実施の形態１におけるＯＮ動作の時と逆極性の電圧を印加する。その他の構成は、図２と同様である。すなわち、図１２では、ＭＯＳＦＥＴ３０，４０のソース側が向き合うように直列に接続されており、このため、ソース・ゲート間電圧が同電位にできるので、ＭＯＳＦＥＴ３０，４０のゲートへのゲートドライブ回路１０４からの信号線を共通にできる。言い換えれば、実施の形態５では、ＭＯＳＦＥＴ３０，４０を同時駆動するが、ＭＯＳＦＥＴ３０，４０のＯＮ／ＯＦＦ動作を１系統のゲート電圧信号によって制御する。図１２では、デプレション型を識別するようにゲート部が実線で示されている。 FIG. 12 is a diagram illustrating an example of an internal configuration of the switching device according to the fifth embodiment. In FIG. 12, n-type depletion type FETs are used as the MOSFETs 30 and 40. Therefore, a source-gate voltage is applied during the OFF operation. At this time, as the applied voltage, a voltage having a polarity opposite to that in the ON operation in the first embodiment is applied. Other configurations are the same as those in FIG. That is, in FIG. 12, the source sides of the MOSFETs 30 and 40 are connected in series so that they face each other, so that the source-gate voltage can be made the same potential, so that the gate drive circuit 104 from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40 A signal line can be shared. In other words, in the fifth embodiment, the MOSFETs 30 and 40 are driven simultaneously, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by a single system gate voltage signal. In FIG. 12, the gate portion is shown by a solid line so as to identify the depletion type.
　図１２において、デプレション型ＦＥＴは、ゲートに電圧を印加していない状態ではソース・ドレイン間に電流が流れるノーマリＯＮとなる。そのため、各太陽電池ストリング１２は、対応するスイッチング装置１０２のＭＯＳＦＥＴ３０，４０の両ゲートに電圧が印加されていなくても発電した電力を負荷装置４００へと供給できる。よって、実施の形態５では、ゲートドライブ回路１０４が、複数の太陽電池ストリング１２と負荷装置４００とを接続する配線から電力の供給を受けるように接続する。これにより、かかる電力をＭＯＳＦＥＴ３０，４０のそれぞれのトランジスタ部３４，４４を駆動するゲート用の電源として使用できる。よって、別電源を不要にできる。 In FIG. 12, the depletion type FET is normally ON in which a current flows between the source and the drain when no voltage is applied to the gate. Therefore, each solar cell string 12 can supply the generated power to the load device 400 even when no voltage is applied to the gates of the MOSFETs 30 and 40 of the corresponding switching device 102. Therefore, in the fifth embodiment, the gate drive circuit 104 is connected so as to be supplied with power from the wiring connecting the plurality of solar cell strings 12 and the load device 400. As a result, such power can be used as a power source for the gate that drives the transistor portions 34 and 44 of the MOSFETs 30 and 40, respectively. Therefore, a separate power source can be eliminated.
　図１２において、例えば、スイッチング装置１０２ａによって、太陽電池ストリング１２ａの配線の開動作（ＯＦＦ）を行う場合、制御部３８によってスイッチング装置１０２ａ，１０２ｂに対して、ゲートＯＦＦにするための制御信号をゲートドライブ回路１０４に出力する。ゲートドライブ回路１０４では、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０の共通するゲート配線へと負のソース・ゲート間電圧を印加する。これにより、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの負極（－）の電位が、発電中の他の太陽電池ストリング１２ｂ等の負極（－）の電位よりも高電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 In FIG. 12, for example, when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104. In the gate drive circuit 104, a negative source-gate voltage is applied to the gate wiring common to the MOSFETs 30 and 40 of the switching device 102a. As a result, both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode (−) of the solar cell string 12a is assumed to be negative ( The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　同様に、ゲートドライブ回路１０４では、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０の共通するゲート配線へと負のソース・ゲート間電圧を印加する。これにより、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの正極（＋）の電位が、発電中の他の太陽電池ストリング１２ｂ等の正極（＋）の電位よりも低電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 Similarly, in the gate drive circuit 104, a negative source-gate voltage is applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102b. As a result, both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　以上のように、実施の形態５によれば、実施の形態１と同様、開閉動作に要する電力を低減させながら太陽電池を太陽光発電システムから電気的に切り離すことができる。 As described above, according to the fifth embodiment, as in the first embodiment, the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
　実施の形態５では、ＭＯＳＦＥＴ３０，４０として、ｎ型デプレション型ＦＥＴのソース同士を接続した場合について示したが、これに限るものではない。実施の形態６では、その他の接続方法について説明する。実施の形態６における太陽光発電システム５００の構成は、図１と同様である。また、以下、特に説明する点以外の内容は、実施の形態１と同様である。 In the fifth embodiment, the case where the sources of n-type depletion type FETs are connected as the MOSFETs 30 and 40 has been described, but the present invention is not limited to this. In the sixth embodiment, other connection methods will be described. The configuration of solar power generation system 500 in the sixth embodiment is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
　図１３は、実施の形態６におけるスイッチング装置の内部構成の一例を示す図である。図１３において、ＭＯＳＦＥＴ３０，４０として、図１２と同様に、ｎ型デプレション型ＦＥＴを用いる。但し、図１３では、ＭＯＳＦＥＴ３０，４０のドレイン側が向き合うように直列に接続される。ドレイン同士が接続される場合には、ソース・ゲート間電圧に必要な電位が異なるので、ＭＯＳＦＥＴ３０，４０のゲートへのゲートドライブ回路１０４からの信号線を別に設けるとよい。言い換えれば、実施の形態６では、ＭＯＳＦＥＴ３０，４０を同時駆動するが、ＭＯＳＦＥＴ３０，４０のＯＮ／ＯＦＦ動作を２系統のゲート電圧信号によって制御する。その他の構成は、図１２と同様である。 FIG. 13 is a diagram illustrating an example of the internal configuration of the switching device according to the sixth embodiment. In FIG. 13, n-type depletion type FETs are used as the MOSFETs 30 and 40 as in FIG. 12. However, in FIG. 13, the MOSFETs 30 and 40 are connected in series so that the drain sides face each other. When the drains are connected to each other, the potential required for the source-gate voltage is different. Therefore, it is preferable to provide a separate signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40. In other words, in the sixth embodiment, the MOSFETs 30 and 40 are driven simultaneously, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by two gate voltage signals. Other configurations are the same as those in FIG.
　実施の形態６では、図９で説明したように、ドレイン同士が接続される場合、ＭＯＳＦＥＴ３０，４０の放熱板同士を接続できるので、素子の放熱性を向上させることができる。 In the sixth embodiment, as described with reference to FIG. 9, when the drains are connected to each other, the heat dissipation plates of the MOSFETs 30 and 40 can be connected to each other, so that the heat dissipation of the element can be improved.
　また、実施の形態６では、デプレション型ＦＥＴを用いている。よって、実施の形態６では、実施の形態５と同様、ゲートドライブ回路１０４が、複数の太陽電池ストリング１２と負荷装置４００とを接続する配線から電力の供給を受けるように接続する。これにより、かかる電力をＭＯＳＦＥＴ３０，４０のそれぞれのトランジスタ部３４，４４を駆動するゲート用の電源として使用できる。よって、別電源を不要にできる。 In the sixth embodiment, a depletion type FET is used. Therefore, in the sixth embodiment, similarly to the fifth embodiment, the gate drive circuit 104 is connected so as to be supplied with electric power from the wiring connecting the plurality of solar cell strings 12 and the load device 400. As a result, such power can be used as a power source for the gate that drives the transistor portions 34 and 44 of the MOSFETs 30 and 40, respectively. Therefore, a separate power source can be eliminated.
　図１３において、例えば、スイッチング装置１０２ａによって、太陽電池ストリング１２ａの配線の開動作（ＯＦＦ）を行う場合、制御部３８によってスイッチング装置１０２ａ，１０２ｂに対して、ゲートＯＦＦにするための制御信号をゲートドライブ回路１０４に出力する。ゲートドライブ回路１０４では、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０のそれぞれのゲート配線へと負のソース・ゲート間電圧を印加にする。これにより、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの負極（－）の電位が、発電中の他の太陽電池ストリング１２ｂ等の負極（－）の電位よりも高電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 In FIG. 13, for example, when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104. In the gate drive circuit 104, a negative source-gate voltage is applied to each gate wiring of the MOSFETs 30 and 40 of the switching device 102a. As a result, both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode (−) of the solar cell string 12a is assumed to be negative ( The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　同様に、ゲートドライブ回路１０４では、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０のそれぞれのゲート配線へと負のソース・ゲート間電圧を印加にする。これにより、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの正極（＋）の電位が、発電中の他の太陽電池ストリング１２ｂ等の正極（＋）の電位よりも低電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 Similarly, in the gate drive circuit 104, a negative source-gate voltage is applied to the respective gate wirings of the MOSFETs 30 and 40 of the switching device 102b. As a result, both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　以上のように、実施の形態６によれば、実施の形態１と同様、開閉動作に要する電力を低減させながら太陽電池を太陽光発電システムから電気的に切り離すことができる。 As described above, according to the sixth embodiment, as in the first embodiment, the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
　実施の形態５では、ＭＯＳＦＥＴ３０，４０として、ｎ型デプレション型ＦＥＴを用いたが、これに限るものではない。実施の形態７では、その他のＭＯＳＦＥＴを用いる場合について説明する。実施の形態７における太陽光発電システム５００の構成は、図１と同様である。また、以下、特に説明する点以外の内容は、実施の形態１と同様である。 In the fifth embodiment, n-type depletion type FETs are used as the MOSFETs 30 and 40. However, the present invention is not limited to this. In the seventh embodiment, a case where another MOSFET is used will be described. The configuration of solar power generation system 500 in Embodiment 7 is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
　図１４は、実施の形態７におけるスイッチング装置の内部構成の一例を示す図である。図１４において、ＭＯＳＦＥＴ３０，４０として、ｐ型デプレション型ＦＥＴを用いる。そのため、ソース・ゲート間電圧の極性が、実施の形態５の場合と逆向きになる。その他の構成は、図１２と同様である。すなわち、図１４では、ＭＯＳＦＥＴ３０，４０のソース側が向き合うように直列に接続されており、ソース・ゲート間電圧が同電位にできるので、ＭＯＳＦＥＴ３０，４０のゲートへのゲートドライブ回路１０４からの信号線を共通にできる。言い換えれば、実施の形態７では、ＭＯＳＦＥＴ３０，４０を同時駆動するが、ＭＯＳＦＥＴ３０，４０のＯＮ／ＯＦＦ動作を１系統のゲート電圧信号によって制御する。その他の構成は、図１２と同様である。 FIG. 14 is a diagram illustrating an example of an internal configuration of the switching device according to the seventh embodiment. In FIG. 14, p-type depletion type FETs are used as the MOSFETs 30 and 40. For this reason, the polarity of the source-gate voltage is opposite to that in the fifth embodiment. Other configurations are the same as those in FIG. That is, in FIG. 14, the source sides of the MOSFETs 30 and 40 are connected in series so that they face each other, and the voltage between the source and gate can be made the same potential, so the signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40 is connected. Can be common. In other words, in the seventh embodiment, the MOSFETs 30 and 40 are simultaneously driven, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by one system of gate voltage signals. Other configurations are the same as those in FIG.
　また、実施の形態７では、デプレション型ＦＥＴを用いている。よって、実施の形態７では、実施の形態５と同様、ゲートドライブ回路１０４が、複数の太陽電池ストリング１２と負荷装置４００とを接続する配線から電力の供給を受けるように接続する。これにより、かかる電力をＭＯＳＦＥＴ３０，４０のそれぞれのトランジスタ部３４，４４を駆動するゲート用の電源として使用できる。よって、別電源を不要にできる。 In the seventh embodiment, a depletion type FET is used. Therefore, in the seventh embodiment, as in the fifth embodiment, the gate drive circuit 104 is connected so as to receive power supply from the wiring connecting the plurality of solar cell strings 12 and the load device 400. As a result, such power can be used as a power source for the gate that drives the transistor portions 34 and 44 of the MOSFETs 30 and 40, respectively. Therefore, a separate power source can be eliminated.
　図１４において、例えば、スイッチング装置１０２ａによって、太陽電池ストリング１２ａの配線の開動作（ＯＦＦ）を行う場合、制御部３８によってスイッチング装置１０２ａ，１０２ｂに対して、ゲートＯＦＦにするための制御信号をゲートドライブ回路１０４に出力する。ゲートドライブ回路１０４では、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０の共通するゲート配線へと正のソース・ゲート間電圧を印加する。これにより、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの負極（－）の電位が、発電中の他の太陽電池ストリング１２ｂ等の負極（－）の電位よりも高電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 In FIG. 14, for example, when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104. In the gate drive circuit 104, a positive source-gate voltage is applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102a. As a result, both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode (−) of the solar cell string 12a is assumed to be negative ( The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　同様に、ゲートドライブ回路１０４では、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０の共通するゲート配線へと正のソース・ゲート間電圧を印加する。これにより、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの正極（＋）の電位が、発電中の他の太陽電池ストリング１２ｂ等の正極（＋）の電位よりも低電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 Similarly, in the gate drive circuit 104, a positive source-gate voltage is applied to the common gate wiring of the MOSFETs 30 and 40 of the switching device 102b. As a result, both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　以上のように、実施の形態７によれば、実施の形態１と同様、開閉動作に要する電力を低減させながら太陽電池を太陽光発電システムから電気的に切り離すことができる。 As described above, according to the seventh embodiment, as in the first embodiment, the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
　実施の形態７では、ＭＯＳＦＥＴ３０，４０として、ｐ型デプレション型ＦＥＴのソース同士を接続した場合について示したが、これに限るものではない。実施の形態４では、その他の接続方法について説明する。実施の形態８における太陽光発電システム５００の構成は、図１と同様である。また、以下、特に説明する点以外の内容は、実施の形態１と同様である。 In the seventh embodiment, the case where the sources of the p-type depletion type FETs are connected to each other as the MOSFETs 30 and 40 has been described. In the fourth embodiment, other connection methods will be described. The configuration of the photovoltaic power generation system 500 in the eighth embodiment is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
　図１５は、実施の形態８におけるスイッチング装置の内部構成の一例を示す図である。図１５において、ＭＯＳＦＥＴ３０，４０として、図１４と同様に、ｐ型デプレション型ＦＥＴを用いる。但し、図１５では、ＭＯＳＦＥＴ３０，４０のドレイン側が向き合うように直列に接続される。ドレイン同士が接続される場合には、ソース・ゲート間電圧に必要な電位が異なるので、ＭＯＳＦＥＴ３０，４０のゲートへのゲートドライブ回路１０４からの信号線を別に設けるとよい。言い換えれば、実施の形態８では、ＭＯＳＦＥＴ３０，４０を同時駆動するが、ＭＯＳＦＥＴ３０，４０のＯＮ／ＯＦＦ動作を２系統のゲート電圧信号によって制御する。その他の構成は、図２と同様である。 FIG. 15 is a diagram illustrating an example of the internal configuration of the switching device according to the eighth embodiment. In FIG. 15, p-type depletion type FETs are used as the MOSFETs 30 and 40 as in FIG. 14. However, in FIG. 15, the MOSFETs 30 and 40 are connected in series so that the drain sides face each other. When the drains are connected to each other, the potential required for the source-gate voltage is different. Therefore, it is preferable to provide a separate signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40. In other words, in the eighth embodiment, the MOSFETs 30 and 40 are simultaneously driven, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by the two systems of gate voltage signals. Other configurations are the same as those in FIG.
　また、図９で説明したように、ドレイン同士が接続される場合、ＭＯＳＦＥＴ３０，４０の放熱板同士を接続できるので、素子の放熱性を向上させることができる。 As described with reference to FIG. 9, when the drains are connected to each other, the heat dissipation plates of the MOSFETs 30 and 40 can be connected to each other, so that the heat dissipation of the element can be improved.
　また、実施の形態８では、デプレション型ＦＥＴを用いている。よって、実施の形態８では、実施の形態５と同様、ゲートドライブ回路１０４が、複数の太陽電池ストリング１２と負荷装置４００とを接続する配線から電力の供給を受けるように接続する。これにより、かかる電力をＭＯＳＦＥＴ３０，４０のそれぞれのトランジスタ部３４，４４を駆動するゲート用の電源として使用できる。よって、別電源を不要にできる。 In the eighth embodiment, a depletion type FET is used. Therefore, in the eighth embodiment, similarly to the fifth embodiment, the gate drive circuit 104 is connected so as to receive power supply from the wiring connecting the plurality of solar cell strings 12 and the load device 400. As a result, such power can be used as a power source for the gate that drives the transistor portions 34 and 44 of the MOSFETs 30 and 40, respectively. Therefore, a separate power source can be eliminated.
　図１５において、例えば、スイッチング装置１０２ａによって、太陽電池ストリング１２ａの配線の開動作（ＯＦＦ）を行う場合、制御部３８によってスイッチング装置１０２ａ，１０２ｂに対して、ゲートＯＦＦにするための制御信号をゲートドライブ回路１０４に出力する。ゲートドライブ回路１０４では、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０のそれぞれのゲート配線へと正のソース・ゲート間電圧を印加する。これにより、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの負極（－）の電位が、発電中の他の太陽電池ストリング１２ｂ等の負極（－）の電位よりも高電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 In FIG. 15, for example, when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning the gate OFF to the switching devices 102a and 102b. Output to the drive circuit 104. In the gate drive circuit 104, a positive source-gate voltage is applied to each gate wiring of the MOSFETs 30 and 40 of the switching device 102a. As a result, both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode (−) of the solar cell string 12a is assumed to be negative ( The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　同様に、ゲートドライブ回路１０４では、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０のそれぞれのゲート配線へと正のソース・ゲート間電圧を印加する。これにより、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの正極（＋）の電位が、発電中の他の太陽電池ストリング１２ｂ等の正極（＋）の電位よりも低電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 Similarly, in the gate drive circuit 104, a positive source-gate voltage is applied to each gate wiring of the MOSFETs 30 and 40 of the switching device 102b. As a result, both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　以上のように、実施の形態８によれば、実施の形態１と同様、開閉動作に要する電力を低減させながら太陽電池を太陽光発電システムから電気的に切り離すことができる。 As described above, according to the eighth embodiment, similarly to the first embodiment, the solar cell can be electrically disconnected from the photovoltaic power generation system while reducing the power required for the opening / closing operation.
　実施の形態１～８では、ＭＯＳＦＥＴ３０，４０として、同じ種類のＭＯＳＦＥＴを使用する例について説明したが、これに限るものではない。実施の形態９では、ＭＯＳＦＥＴ３０，４０として、異なる種類のＭＯＳＦＥＴを使用する場合について説明する。実施の形態９における太陽光発電システム５００の構成は、図１と同様である。また、以下、特に説明する点以外の内容は、実施の形態１と同様である。 In the first to eighth embodiments, the example in which the same type of MOSFET is used as the MOSFETs 30 and 40 has been described. However, the present invention is not limited to this. In the ninth embodiment, a case where different types of MOSFETs are used as the MOSFETs 30 and 40 will be described. The configuration of solar power generation system 500 in the ninth embodiment is the same as that in FIG. Further, the contents other than those specifically described below are the same as those in the first embodiment.
　図１６は、実施の形態９におけるスイッチング装置の内部構成の一例を示す図である。図１６において、ＭＯＳＦＥＴ３０として、ｎ型エンハンスメント型ＦＥＴを用いる。そして、ＭＯＳＦＥＴ４０として、ｐ型デプレション型ＦＥＴを用いる。そして、ＭＯＳＦＥＴ３０のソース側と、ＭＯＳＦＥＴ４０のドレイン側とが向き合うように直列に接続される。ここでは、ソース・ゲート間電圧に必要な電位が異なるので、ＭＯＳＦＥＴ３０，４０のゲートへのゲートドライブ回路１０４からの信号線を別に設けるとよい。言い換えれば、実施の形態９では、ＭＯＳＦＥＴ３０，４０を同時駆動するが、ＭＯＳＦＥＴ３０，４０のＯＮ／ＯＦＦ動作を２系統のゲート電圧信号によって制御する。その他の構成は、図２と同様である。 FIG. 16 is a diagram illustrating an example of an internal configuration of the switching device according to the ninth embodiment. In FIG. 16, an n-type enhancement type FET is used as the MOSFET 30. A p-type depletion type FET is used as the MOSFET 40. The source side of the MOSFET 30 and the drain side of the MOSFET 40 are connected in series so as to face each other. Here, since the potentials required for the source-gate voltage are different, a signal line from the gate drive circuit 104 to the gates of the MOSFETs 30 and 40 may be provided separately. In other words, in the ninth embodiment, the MOSFETs 30 and 40 are driven simultaneously, but the ON / OFF operation of the MOSFETs 30 and 40 is controlled by two systems of gate voltage signals. Other configurations are the same as those in FIG.
　図１６において、例えば、スイッチング装置１０２ａによって、太陽電池ストリング１２ａの配線の開動作（ＯＦＦ）を行う場合、制御部３８によってスイッチング装置１０２ａ，１０２ｂに対して、ゲートＯＦＦにするための制御信号をゲートドライブ回路１０４に出力する。ゲートドライブ回路１０４では、スイッチング装置１０２ａのＭＯＳＦＥＴ３０のゲート配線へと印加している正のソース・ゲート間電圧をＯＦＦにする。そして、スイッチング装置１０２ａのＭＯＳＦＥＴ４０のゲート配線へと正のソース・ゲート間電圧を印加する。これにより、スイッチング装置１０２ａのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの負極（－）の電位が、発電中の他の太陽電池ストリング１２ｂ等の負極（－）の電位よりも高電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 In FIG. 16, for example, when the switching device 102a performs the opening operation (OFF) of the wiring of the solar cell string 12a, the control unit 38 gates a control signal for turning off the gate to the switching devices 102a and 102b. Output to the drive circuit 104. In the gate drive circuit 104, the positive source-gate voltage applied to the gate wiring of the MOSFET 30 of the switching device 102a is turned off. Then, a positive source-gate voltage is applied to the gate wiring of the MOSFET 40 of the switching device 102a. As a result, both the MOSFETs 30 and 40 of the switching device 102a are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are disposed in the opposite directions, the potential of the negative electrode (−) of the solar cell string 12a is assumed to be negative ( The leakage current can be cut off even when the potential becomes higher than the potential of-). Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　同様に、ゲートドライブ回路１０４では、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０のゲート配線へと印加している正のソース・ゲート間電圧をＯＦＦにする。そして、スイッチング装置１０２ａのＭＯＳＦＥＴ４０のゲート配線へと正のソース・ゲート間電圧を印加する。これにより、スイッチング装置１０２ｂのＭＯＳＦＥＴ３０，４０が共にゲートＯＦＦになり、ＭＯＳＦＥＴ３０，４０が共にソース・ドレイン間を遮断する。その際、ＭＯＳＦＥＴ３０，４０のダイオード部３２，４２は逆向きに配置されているので、仮に、太陽電池ストリング１２ａの正極（＋）の電位が、発電中の他の太陽電池ストリング１２ｂ等の正極（＋）の電位よりも低電位になっても漏れ電流は遮断できる。よって、太陽光発電システム５００からの影響は回避できる。 Similarly, in the gate drive circuit 104, the positive source-gate voltage applied to the gate wiring of the MOSFET 30 of the switching device 102b is turned off. Then, a positive source-gate voltage is applied to the gate wiring of the MOSFET 40 of the switching device 102a. As a result, both the MOSFETs 30 and 40 of the switching device 102b are turned off, and both the MOSFETs 30 and 40 cut off between the source and the drain. At this time, since the diode portions 32 and 42 of the MOSFETs 30 and 40 are arranged in the reverse direction, the potential of the positive electrode (+) of the solar cell string 12a is assumed to be positive (such as other solar cell strings 12b during power generation). Even if the potential becomes lower than the potential of +), the leakage current can be cut off. Therefore, the influence from the photovoltaic power generation system 500 can be avoided.
　以上のように、ＭＯＳＦＥＴ３０，４０の一方に、エンハンスメント型のＭＯＳＦＥＴを用い、他方にデプレション型のＭＯＳＦＥＴを用いてもよい。ｎ型エンハンスメント型ＦＥＴとｐ型デプレション型ＦＥＴの組み合わせにすることで、ゲート電圧の符号を正に合わせることができる。 As described above, an enhancement type MOSFET may be used for one of the MOSFETs 30 and 40 and a depletion type MOSFET may be used for the other. By using a combination of an n-type enhancement type FET and a p-type depletion type FET, the sign of the gate voltage can be positively matched.
　以上のように、実施の形態９によれば、異なる種類のＭＯＳＦＥＴを使用する場合でも、実施の形態１と同様、開閉動作に要する電力を低減させながら太陽電池を太陽光発電システムから電気的に切り離すことができる。 As described above, according to the ninth embodiment, even when different types of MOSFETs are used, as in the first embodiment, the solar cell is electrically removed from the photovoltaic power generation system while reducing the power required for the opening / closing operation. Can be separated.
　実施の形態１～９では、図１に示したように、故障検知装置２００内に逆流防止用のダイオード２０，２１を配置したが、これに限るものではない。実施の形態１０では、その他の構成について説明する。 In Embodiments 1 to 9, as shown in FIG. 1, the diodes 20 and 21 for backflow prevention are arranged in the failure detection apparatus 200, but the present invention is not limited to this. In the tenth embodiment, other configurations will be described.
　図１７は、実施の形態１０における太陽光発電システムの構成の一部を示す構成図である。図１７において、太陽光発電システム５００は、故障検知装置２００と、接続箱２０２，２０４と、太陽電池アレイ３００と、図示しない負荷装置４００と、を備えている。図１７では、接続箱２０２内に、各太陽電池ストリング１２ａ～ｄの正極（＋）側の逆流防止用のダイオード２０ａ～ｄと、遮断器４０２と、遮断器或いは断路器といったスイッチ２２ａ～ｄと、が配置された点、接続箱２０４内に、各太陽電池ストリング１２ａ～ｄの正極（＋）側の逆流防止用のダイオード２１ａ～ｄと、遮断器４０４と、遮断器或いは断路器といったスイッチ２４ａ～ｄと、が配置された点、以外は、図１と同様である。図１７に示すように、接続箱２０２，２０４を故障検知装置２００とは別に用意してもよい。 FIG. 17 is a configuration diagram illustrating a part of the configuration of the photovoltaic power generation system according to the tenth embodiment. In FIG. 17, the photovoltaic power generation system 500 includes a failure detection device 200, connection boxes 202 and 204, a solar cell array 300, and a load device 400 (not shown). In FIG. 17, in the junction box 202, the backflow prevention diodes 20a to 20d on the positive electrode (+) side of the solar cell strings 12a to 12d, a circuit breaker 402, and switches 22a to 22d such as a circuit breaker or a disconnect circuit , Are disposed in the junction box 204, and the reverse current preventing diodes 21a to 21d on the positive electrode (+) side of each of the solar cell strings 12a to 12d, a circuit breaker 404, and a switch 24a such as a circuit breaker or disconnector. 1 is the same as FIG. 1 except that .about.d are arranged. As shown in FIG. 17, the junction boxes 202 and 204 may be prepared separately from the failure detection apparatus 200.
　図１８は、各実施の形態における検知部の内部構成の一例を示す図である。まず、複数の太陽電池ストリングの中から一の太陽電池ストリング１２ａを選択する（Ｓ１）。続いて、選択した一の太陽電池ストリング１２ａの正極側と負極側とに対応する解列用のスイッチング装置１０２ａ，１０２ｂをオフにする。これにより、当該太陽電池ストリング１２ａを太陽光発電システム５００から電気的に切り離して解列し、解列状態とする（Ｓ２）。 FIG. 18 is a diagram illustrating an example of the internal configuration of the detection unit in each embodiment. First, one solar cell string 12a is selected from a plurality of solar cell strings (S1). Subsequently, the switching devices 102a and 102b for disconnection corresponding to the positive electrode side and the negative electrode side of the selected one solar cell string 12a are turned off. Thereby, the said solar cell string 12a is electrically disconnected from the photovoltaic power generation system 500, and is disconnected, and it is set as a disconnected state (S2).
　続いて、解列状態の太陽電池ストリング１２ａにおける正極側と負極側とに接続するスイッチング装置３１，３３を閉（ＯＮ）にし、この太陽電池ストリング１２ａを検知部３６に接続する（Ｓ３）。続いて、解列状態の太陽電池ストリング１２ａについて、図１８に示す正極側スイッチ素子８ｘをオンにすると共に負極側スイッチ素子８ｙをオフにし、正極側のみを検出抵抗９の他方側に接続すると共に負極側を解放する（Ｓ４）。この状態で、電圧検出器６により検出抵抗９の第１電圧降下値とその符号とを測定する（Ｓ５）。スイッチ素子８は、制御部３８からの指示信号に応じてオンオフを切り替える。 Subsequently, the switching devices 31 and 33 connected to the positive electrode side and the negative electrode side in the disconnected solar cell string 12a are closed (ON), and the solar cell string 12a is connected to the detection unit 36 (S3). Subsequently, for the solar cell string 12a in the disconnected state, the positive electrode side switch element 8x shown in FIG. 18 is turned on, the negative electrode side switch element 8y is turned off, and only the positive electrode side is connected to the other side of the detection resistor 9. The negative electrode side is released (S4). In this state, the voltage detector 6 measures the first voltage drop value of the detection resistor 9 and its sign (S5). The switch element 8 switches on and off according to an instruction signal from the control unit 38.
　また、解列状態の太陽電池ストリング１２ａについて、正極側スイッチ素子８ｘをオフ状態にすると共に負極側スイッチ素子８ｙをオンにし、負極側のみを検出抵抗９の他方側に接続すると共に正極側を解放する（Ｓ６）。この状態で、電圧検出器６により検出抵抗９の第２電圧降下値とその符号とを測定する（Ｓ７）。 Further, for the solar cell string 12a in the disconnected state, the positive electrode side switch element 8x is turned off and the negative electrode side switch element 8y is turned on, and only the negative electrode side is connected to the other side of the detection resistor 9 and the positive electrode side is released. (S6). In this state, the voltage detector 6 measures the second voltage drop value of the detection resistor 9 and its sign (S7).
　さらに、解列状態の太陽電池ストリング１２ａについて、正極側スイッチ素子８ｘ及び負極側スイッチ素子８ｙの両方をオフにし、検出抵抗９に対して非接続とする（切り離す）。この状態で、電圧検出器６により太陽電池ストリング１０３の極間電圧値とその符号とを測定する（Ｓ８，９）。なお、上記Ｓ４，５と上記Ｓ６，７と上記Ｓ８，９とは、互いに順不同であり、上記Ｓ６，７を最初に実施してもよいし、上記Ｓ８，９を最初に実施してもよい。 Furthermore, for the solar cell string 12a in the disconnected state, both the positive electrode side switch element 8x and the negative electrode side switch element 8y are turned off and disconnected (disconnected) from the detection resistor 9. In this state, the voltage detector 6 measures the voltage value between the electrodes of the solar cell string 103 and its sign (S8, 9). Note that S4, 5, S6, 7 and S8, 9 are out of order with each other, and S6, 7 may be performed first, or S8, 9 may be performed first. .
　続いて、制御部３８は、測定した第１及び第２電圧降下値、極間電圧値、及びこれらの符号を用いて、絶縁抵抗値を演算する（Ｓ１０）。具体的には、以下の式（１）を用いて、絶縁抵抗値Ｒｌｅａｋを算出する。
（１）　Ｒｌｅａｋ＝Ｒｄ×｜Ｖ０／（Ｖ１－Ｖ２）｜－Ｒｄ Then, the control part 38 calculates an insulation resistance value using the measured 1st and 2nd voltage drop value, the voltage value between electrodes, and these codes | symbols (S10). Specifically, the insulation resistance value R leak is calculated using the following equation (1).
(1) R leak = R d × | V 0 / (V 1 −V 2 ) | −R d
　但し、
Ｒｄ：検出抵抗９の抵抗値、
Ｖ０：極間電圧値
Ｖ１：第１電圧降下値
Ｖ２：第２電圧降下値 However,
R d : resistance value of the detection resistor 9,
V 0 : Inter-electrode voltage value V 1 : First voltage drop value V 2 : Second voltage drop value
　続いて、制御部３８は、演算した絶縁抵抗値Ｒｌｅａｋと、予め設定された基準抵抗値とを比較し、地絡判定を行う（Ｓ１１）。具体的には、演算した絶縁抵抗値Ｒｌｅａｋが基準抵抗値以上であれば、「地絡無し」と判定する一方、絶縁抵抗値Ｒｌｅａｋが基準抵抗値未満であれば、「地絡あり」と判定する。 Subsequently, the control unit 38 compares the calculated insulation resistance value R leak with a preset reference resistance value, and performs a ground fault determination (S11). Specifically, if the calculated insulation resistance value R leak is equal to or greater than the reference resistance value, it is determined that there is no ground fault. On the other hand, if the insulation resistance value R leak is less than the reference resistance value, “ground fault exists”. Is determined.
　続いて、地絡判定結果が「地絡無し」であれば、解列状態の太陽電池ストリング１２ａについて、解列用のスイッチング装置１０２ａ，１０２ｂをオン状態にして太陽光発電システム５００に接続すると共に、測定用のスイッチング装置３１，３３をオフにして検知部３６から切り離す。 Subsequently, if the ground fault determination result is “no ground fault”, the disconnection switching devices 102a and 102b are turned on and connected to the photovoltaic power generation system 500 for the disconnection solar cell string 12a. Then, the switching devices 31 and 33 for measurement are turned off and separated from the detection unit 36.
　以上のように、太陽電池アレイ３００内の地絡検出の際、太陽電池アレイ３００を構成する太陽電池ストリング１２を太陽光発電システム５００から解列し、そして、この解列状態の太陽電池ストリング１２の地絡を検出する。このように、地絡検出対象を小さい単位として地絡を検出することから、地絡検出対象の対地静電容量を下げることができ（つまり、地絡検出対象の電路を短くし、及び総面積を小さくすることができ）、対地静電容量により流れる電流の悪影響が地絡検出に及ぶのを抑制することが可能となる。 As described above, when detecting a ground fault in the solar cell array 300, the solar cell strings 12 constituting the solar cell array 300 are disconnected from the photovoltaic power generation system 500, and the solar cell strings 12 in the disconnected state are separated. Detecting a ground fault. Thus, since the ground fault is detected with the ground fault detection target as a small unit, the ground capacitance of the ground fault detection target can be reduced (that is, the electric circuit of the ground fault detection target is shortened and the total area is reduced). It is possible to reduce the adverse effect of the current flowing due to the ground capacitance on ground fault detection.
　さらに、地絡検出時に太陽電池ストリング１２がパワーコンディショナー等の負荷装置４００に対して電気的に切り離されることとなり、よって、当該パワーコンディショナーに起因して発生するノイズの悪影響が地絡検出に及ぶのをも抑制することができる。従って、本実施形態によれば、地絡を確実に検出することが可能となる。 Furthermore, the solar cell string 12 is electrically disconnected from the load device 400 such as a power conditioner at the time of detecting a ground fault. Therefore, the adverse effect of noise generated due to the power conditioner reaches the ground fault detection. Can also be suppressed. Therefore, according to the present embodiment, it is possible to reliably detect a ground fault.
　上述した各実施の形態では、検知部３６を、太陽電池ストリング１２の正極（＋）側および負極側の双方に接続する場合について説明したが、これに限定する必要はなく、正極（＋）側または負極側に接続する構成としても良い。 In each of the above-described embodiments, the case where the detection unit 36 is connected to both the positive electrode (+) side and the negative electrode side of the solar cell string 12 has been described. However, the present invention is not limited to this, and the positive electrode (+) side is not limited thereto. Or it is good also as a structure connected to a negative electrode side.
　図１９は、各実施の形態における検知部の内部構成の別の一例を示す図である。図１９において、検知部３６は、第１接地電路８１Ａ、第１抵抗８４Ａ、第１直流電源８２Ａ及び第１電流計８６Ａを含む第１測定系と、第２接地電路８１Ｂ、第２抵抗８４Ｂ、第２直流電源８２Ｂ及び第２電流計８６Ｂを含む第２測定系と、を有している。 FIG. 19 is a diagram illustrating another example of the internal configuration of the detection unit in each embodiment. In FIG. 19, the detection unit 36 includes a first grounding circuit 81A, a first resistor 84A, a first DC power supply 82A and a first ammeter 86A, a second grounding circuit 81B, a second resistor 84B, A second measurement system including a second DC power supply 82B and a second ammeter 86B.
　第１接地電路８１Ａは、その一方側が大地Ｇに接続されている。また第１接地電路８１Ａは、その他方側が、検知対象となる太陽電池ストリング１２ａの正極（＋）側の配線（電路）に接続可能とされている。具体的には、第１接地電路８１Ａの他方側は、第１スイッチ部８０Ａ及びスイッイング装置３１を介して、太陽電池ストリング１２ａの正極（＋）側の配線に接続されている。 The first grounding electric circuit 81A has one side connected to the ground G. The other side of the first grounding electric circuit 81A can be connected to the wiring (electric circuit) on the positive electrode (+) side of the solar cell string 12a to be detected. Specifically, the other side of the first grounding electric circuit 81A is connected to the positive (+) side wiring of the solar cell string 12a through the first switch unit 80A and the switching device 31.
　第１スイッチ部８０Ａは、太陽電池ストリング１２ａに対する第１接地電路８１Ａの電気的な接続／非接続を切り替えるものである。第１スイッチ部８０Ａとしては、ＦＥＴ等の半導体スイッチや、リレースイッチ等の機械式スイッチを用いることができる。この第１スイッチ部８０Ａは、制御部３８に接続されており、制御部３８からの指示信号に応じてオンオフを切り替える。 The first switch unit 80A switches the electrical connection / disconnection of the first grounding electric circuit 81A with respect to the solar cell string 12a. As the first switch portion 80A, a semiconductor switch such as an FET or a mechanical switch such as a relay switch can be used. The first switch unit 80A is connected to the control unit 38 and switches on and off according to an instruction signal from the control unit 38.
　第１抵抗８４Ａは、第１接地電路８１Ａ上において第１スイッチ部８０Ａと大地Ｇとの間に設けられている。この第１抵抗８４Ａの抵抗値Ｒｄは、地絡発生時の安全性の観点から所定下限値以上とされ、且つ、測定値の測定容易性の観点から所定上限値以下とされている（以下の第１抵抗８４Ｂにおいて同様）。 The first resistor 84A is provided between the first switch unit 80A and the ground G on the first grounding electric circuit 81A. Resistance R d of the first resistor 84A is in terms of safety upon the ground fault occurs or exceeds a predetermined lower limit value, and is equal to or less than a predetermined upper limit value in terms of measuring the ease of measurement (hereinafter The same applies to the first resistor 84B).
　第１直流電源８２Ａは、第１接地電路８１Ａ上において第１スイッチ部８０Ａと第１抵抗８４Ａとの間（第１抵抗８４Ａよりも太陽電池ストリング１２ａ側）に設けられている。つまり、第１直流電源８２Ａは、その負極側としての一方側が第１抵抗８４Ａに接続され、その正極側としての他方側が第１スイッチ部８０Ａを介して太陽電池ストリング１２ａの正極側に接続されている。この第１直流電源８２Ａは、太陽電池ストリング１２ａの正極側に対し正電圧の直流電圧（ＤＣ電圧）を印加する。ここでは、第１直流電源８２Ａは、第１直流電圧値Ｖ１の直流電圧を印加する。 The first DC power supply 82A is provided between the first switch section 80A and the first resistor 84A (on the solar cell string 12a side with respect to the first resistor 84A) on the first grounding electric circuit 81A. That is, the first DC power supply 82A has one side as the negative electrode side connected to the first resistor 84A and the other side as the positive electrode side connected to the positive electrode side of the solar cell string 12a via the first switch portion 80A. Yes. The first DC power supply 82A applies a positive DC voltage (DC voltage) to the positive electrode side of the solar cell string 12a. Here, the first DC power source 82A applies a first DC voltage of the DC voltage value V 1.
　第１直流電圧値Ｖ１は、地絡検出の感度向上の観点から所定下限値以上とされ、且つ、測定対象の太陽電池回路を破損防止する観点から所定上限値以下とされている（以下の直流電圧値において同様）。この第１直流電源８２Ａは、制御部３８に接続されており、制御部３８からの指示信号に応じて第１直流電圧値Ｖ１を印加する。 The first DC voltage value V 1 is set to a predetermined lower limit value or more from the viewpoint of improving the sensitivity of ground fault detection, and is set to a predetermined upper limit value or less from the viewpoint of preventing damage to the solar cell circuit to be measured (the following Same for DC voltage value). The first DC power supply 82A is connected to the control unit 38, first applying a DC voltage value V 1 in response to an instruction signal from the control unit 38.
　第１電流計８６Ａは、第１接地電路８１Ａ上において第１抵抗８４Ａと大地Ｇとの間に設けられている。この第１電流計８６Ａは、第１接地電路８１Ａにて第１抵抗８４Ａを介して流れる漏れ電流値としての第１電流値（第１測定値）Ｉ１を測定する。また、第１電流計８６Ａは、制御部３８に接続されており、制御部３８からの指示信号に応じて第１直流電圧値Ｖ１の測定を実行する。第１電流計８６Ａとしては、例えばホール素子を利用した直流零相電流検出器等が用いられる。 The first ammeter 86A is provided between the first resistor 84A and the ground G on the first grounding electric circuit 81A. The first ammeter 86A is the first current value as the leakage current value at the first ground path 81A flows through the first resistor 84A (first measurement) is measured I 1. The first ammeter 86A is connected to the control unit 38, first to perform the measurement of the DC voltage value V 1 in response to an instruction signal from the control unit 38. As the first ammeter 86A, for example, a DC zero-phase current detector using a Hall element is used.
　他方、第２接地電路８１Ｂは、その一方側が大地Ｇに接続されている。また第２接地電路８１Ｂは、その他方側が太陽電池ストリング１２ａの正極の配線（電路）に接続可能とされている。具体的には、第２接地電路８１Ｂの他方側は、第２スイッチ部８０Ｂ及びスイッチング装置３１を介して、太陽電池ストリング１２ａの正極側の配線に接続されている。 On the other hand, one side of the second grounding electric circuit 81B is connected to the ground G. The other side of the second grounding electric circuit 81B is connectable to the positive wiring (electric circuit) of the solar cell string 12a. Specifically, the other side of the second grounding electric circuit 81B is connected to the positive electrode side wiring of the solar cell string 12a via the second switch unit 80B and the switching device 31.
　第２スイッチ部８０Ｂは、太陽電池ストリング１２ａに対する第２接地電路８１Ｂの電気的な接続／非接続を切り替えるものである。第２スイッチ部８０Ｂとしては、第１スイッチ部８０Ａと同様に、ＦＥＴ等の半導体スイッチや、リレースイッチ等の機械式スイッチを用いることができる。この第２スイッチ部８０Ｂは、制御部３８に接続されており、制御部３８からの指示信号に応じてオンオフを切り替える。 The second switch unit 80B switches electrical connection / disconnection of the second grounding electric circuit 81B with respect to the solar cell string 12a. As the second switch unit 80B, similarly to the first switch unit 80A, a semiconductor switch such as an FET or a mechanical switch such as a relay switch can be used. The second switch unit 80B is connected to the control unit 38 and switches on and off according to an instruction signal from the control unit 38.
　第２抵抗８４Ｂは、第２接地電路８１Ｂ上において第２スイッチ部８０Ｂと大地Ｇとの間に設けられている。この第２抵抗８４Ｂの抵抗値は、第１抵抗８４Ａと等しい抵抗値Ｒｄにすると好適である。 The second resistor 84B is provided between the second switch unit 80B and the ground G on the second grounding electric circuit 81B. Resistance of the second resistor 84B are preferable to the equal resistance value R d and the first resistor 84A.
　第２直流電源８２Ｂは、第２接地電路８１Ｂ上において第２スイッチ部８０Ｂと第１抵抗８４Ｂとの間（第２抵抗２２Ｂよりも太陽電池ストリング１２ａ側）に設けられている。つまり、第２直流電源８２Ｂは、その負極側としての一方側が第２抵抗８４Ｂに接続され、その正極側としての他方側が第２スイッチ部８０Ｂを介して太陽電池ストリング１２ａの正極側に接続されている。この第２直流電源８２Ｂは、太陽電池ストリング１２ａの正極側に対し正電圧の直流電圧（ＤＣ電圧）を印加する。ここでは、第２直流電源８２Ｂは、第２直流電圧値Ｖ２の直流電圧を印加する。 The second DC power source 82B is provided between the second switch unit 80B and the first resistor 84B (on the solar cell string 12a side with respect to the second resistor 22B) on the second ground circuit 81B. That is, the second DC power supply 82B has one side as the negative electrode side connected to the second resistor 84B, and the other side as the positive electrode side connected to the positive electrode side of the solar cell string 12a via the second switch portion 80B. Yes. The second DC power supply 82B applies a positive DC voltage (DC voltage) to the positive electrode side of the solar cell string 12a. Here, the second DC power source 82B applies a second DC voltage of the DC voltage value V 2.
　第２直流電圧値Ｖ２は、第１直流電圧値Ｖ１とは異なる電圧値とされている。この第２直流電源８２Ｂは、制御部３８に接続されており、制御部３８からの指示信号に応じて第２直流電圧値Ｖ２を印加する。 Second DC voltage V 2 is different from the voltage value from the first DC voltage value V 1. The second DC power supply 82B is connected to the control unit 38, the second applying a DC voltage value V 2 in response to an instruction signal from the control unit 38.
　第２電流計８６Ｂは、第２接地電路８１Ｂ上において第２抵抗８４Ｂと大地Ｇとの間に設けられている。この第２電流計８６Ｂは、第２接地電路８１Ｂにて第２抵抗８４Ｂを介して流れる漏れ電流値としての第２電流値（第２測定値）Ｉ２を測定する。また、第２電流計８６Ｂは、制御部３８に接続されており、制御部３８からの指示信号に応じて第２直流電圧値Ｖ２の測定を実行する。第２電流計８６Ｂとしては、第１電流計２４Ａと同様に、例えばホール素子を利用した直流零相電流検出器等が用いられる。 The second ammeter 86B is provided between the second resistor 84B and the ground G on the second grounding electric circuit 81B. The second ammeter 86B is a second current value as the leakage current value in the second ground path 81B flows through the second resistor 84B (second measured value) is measured I 2. The second ammeter 86B is connected to the control unit 38, the second performs measurement of the DC voltage value V 2 in response to an instruction signal from the control unit 38. As the second ammeter 86B, for example, a DC zero-phase current detector using a Hall element or the like is used similarly to the first ammeter 24A.
　図１９に示すように、第１直流電源８２Ａから第１直流電圧値Ｖ１が印加される電圧印加箇所と、第２直流電源８２Ｂから第２直流電圧値Ｖ２が印加される電圧印加箇所とは、少なくとも太陽電池ストリング１２ａの定格出力想定時において電位が互いに等しくなっている。換言すると、第１及び第２所定箇所は、設計上の電位が互いに等しくされている。 As shown in FIG. 19, a voltage application location where the first DC voltage value V 1 is applied from the first DC power supply 82A, and a voltage application location where the second DC voltage value V 2 is applied from the second DC power supply 82B. Are equal to each other at least when the rated output of the solar cell string 12a is assumed. In other words, the design potentials of the first and second predetermined portions are equal to each other.
　また、制御部３８は、測定結果に基づき演算を実施し、地絡箇所Ｔの絶縁抵抗値ＲＬ及び電位ＶＬを検出すると共に地絡の有無を検出（判定）する地絡検出機能を有している。 Further, the control unit 38 has a ground fault detection function for performing calculation based on the measurement result, detecting the insulation resistance value R L and the potential V L of the ground fault location T, and detecting (determining) the presence or absence of the ground fault. is doing.
　まず、第１スイッチ部８０Ａをオンとし、第１接地電路８１Ａを太陽電池ストリング１２ａの正極側と接続すると共に、第２スイッチ部８０Ｂをオフのままとし、第２接地電路８１Ｂを太陽電池ストリング１２ａの正極側と非接続にする。これと共に、第１直流電源８２Ａにより、太陽電池ストリング１２ａの正極側に正電圧の第１直流電圧値Ｖ１を印加する。この状態で、第１接地電路８１Ａにて流れる第１電流値Ｉ１を電流計８６Ａにより測定する。 First, the first switch portion 80A is turned on, the first grounding electric circuit 81A is connected to the positive electrode side of the solar cell string 12a, the second switch unit 80B is kept off, and the second grounding electric circuit 81B is connected to the solar cell string 12a. Not connected to the positive electrode side. At the same time, the first DC power source 82A, applying a first DC voltage value V 1 of the positive voltage to the positive electrode side of the solar cell string 12a. In this state, the first current value I 1 flowing in the first ground path 81A is measured by ammeter 86A.
　続いて、第１スイッチ部８０Ａをオフとし、第１接地電路８１Ａを太陽電池ストリング１２ａの正極側と非接続にすると共に、第２スイッチ部８０Ｂをオンとし、第２接地電路８１Ｂを太陽電池ストリング１２ａの正極側と接続する。これと共に、第２直流電源８２Ｂにより、太陽電池ストリング１２ａの正極側に正電圧の第２直流電圧値Ｖ２を印加する。この状態で、第１接地電路８１Ｂにて流れる第２電流値Ｉ２を電流計８６Ｂにより測定する。 Subsequently, the first switch unit 80A is turned off, the first grounding circuit 81A is disconnected from the positive electrode side of the solar cell string 12a, the second switch unit 80B is turned on, and the second grounding circuit 81B is connected to the solar cell string. It connects with the positive electrode side of 12a. At the same time, the second DC power source 82B, applying a second DC voltage value V 2 of the positive voltage to the positive electrode side of the solar cell string 12a. In this state, the second current value I 2 flowing in the first ground path 81B is measured by a current meter 86B.
　続いて、第１及び第２電流値Ｉ１，Ｉ２の変化に基づいて、地絡の有無を判定する。すなわち、以下の式（２）により第１及び第２電流値Ｉ１，Ｉ２から絶縁抵抗値ＲＬを演算し検出する。
（２）　ＲＬ＝（Ｖ１－Ｖ２）／（Ｉ１－Ｉ２）
　　　　　　　－（Ｒｄ２×Ｉ２－Ｒｄ１×Ｉ１）／（Ｉ１－Ｉ２） Subsequently, the presence / absence of a ground fault is determined based on changes in the first and second current values I 1 and I 2 . That is, the insulation resistance value R L is calculated and detected from the first and second current values I 1 and I 2 according to the following equation (2).
(2) R L = (V 1 −V 2 ) / (I 1 −I 2 )
-(R d2 × I 2 -R d1 × I 1 ) / (I 1 -I 2 )
　また、以下の式（３）により第１及び第２電流値Ｉ１，Ｉ２から地絡箇所Ｔの電位ＶＬを演算し検出する。
（３）　ＶＬ＝（Ｖ１・Ｉ２－Ｖ２・Ｉ１＋Ｉ１・Ｉ２×（Ｒｄ２―Ｒｄ１））／（Ｉ１－Ｉ２） Further, the potential V L of the ground fault location T is calculated and detected from the first and second current values I 1 and I 2 by the following equation (3).
(3) V L = (V 1 · I 2 -V 2 · I 1 + I 1 · I 2 × (R d2 -R d1 )) / (I 1 -I 2 )
　そして、演算した絶縁抵抗値ＲＬと、予め設定されている基準抵抗値とを比較し、太陽電池ストリング１２ａの地絡判定を行う。具体的には、絶縁抵抗値ＲＬが基準抵抗値よりも小さい場合、「地絡あり」と判定する一方、絶縁抵抗値ＲＬが基準抵抗値以上の場合、「地絡無し」と判定する。 Then, the calculated insulation resistance value RL is compared with a preset reference resistance value to determine the ground fault of the solar cell string 12a. Specifically, when the insulation resistance value RL is smaller than the reference resistance value, it is determined that “ground fault exists”, while when the insulation resistance value RL is equal to or greater than the reference resistance value, it is determined that there is no ground fault. .
　従って、本実施形態によれば、低コストで精度よく地絡を検出することが可能となる。また、地絡を検出するに当たって短絡動作が必要とされず、安全性を高めることも可能となる。さらには、例えば零相電流検出法による地絡検出の場合のように、地絡検出に事故電流の発生が前提となっていないため、当該事故電流の発生を抑制することが可能となる。 Therefore, according to the present embodiment, it is possible to accurately detect the ground fault at low cost. Moreover, when detecting a ground fault, a short circuit operation is not required, and safety can be improved. Furthermore, since the occurrence of an accident current is not a prerequisite for ground fault detection, as in the case of ground fault detection by the zero-phase current detection method, for example, the occurrence of the accident current can be suppressed.
　以上、具体例を参照しつつ実施の形態について説明した。しかし、本発明は、これらの具体例に限定されるものではない。例えば、上述した例では、遮断部として機能する半導体素子として、ＭＯＳＦＥＴ４０を用いたが、これに限るものではない。代わりに、ＩＧＢＴ（Ｉｎｓｕｌａｔｅｄ　Ｇａｔｅ　Ｂｉｐｏｌａｒ　Ｔｒａｎｓｉｓｔｏｒ）等を用いても好適である。遮断部として用いるＩＧＢＴは、ＭＯＳＦＥＴに比べ高耐圧の要求、高電流を遮断するときに有効で、更に、高耐圧の要求、高電流の遮断を要求される場合は、ＳＣＲ（Ｓｉｌｉｃｏｎ　Ｃｏｎｔｒｏｌｌｅｄ　Ｒｅｃｔｉｆｉｅｒ）又は、ＧＴＯ（Ｇａｔｅ　Ｔｕｒｎ　Ｏｆｆ　Ｔｈｙｒｉｓｔｏｒ）を用いることが有効である。更に、上記のＭＯＳＦＥＴ、ＩＧＢＴ、ＳＣＲ、ＧＴＯは、シリコンで構成されるが、シリコンよりもスイッチング性能の良いと言われている炭化ケイ素で構成したものであっても構わない。更に、他のスイッチング速度を高めるには、ヒ化ガリウム、ヒ化ガリウムアルミニウム等の化合物半導体のスイッチング素子を用いることも可能である。また、上述した故障検知の手法は、一例であって、図１８、図１９で説明したものに限るものではない。その他の地絡等の故障検知手法を用いてもよい。 The embodiment has been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, in the above-described example, the MOSFET 40 is used as a semiconductor element that functions as a blocking unit, but the present invention is not limited to this. Instead, it is also preferable to use an IGBT (Insulated Gate Bipolar Transistor) or the like. An IGBT used as a blocking unit is effective when blocking a high voltage and a high current as compared with a MOSFET. When a high voltage and a high current are required, an SCR (Silicon Controlled Rectifier) or It is effective to use GTO (Gate Turn Off Thyristor). Further, the MOSFET, IGBT, SCR, and GTO are made of silicon, but may be made of silicon carbide, which is said to have better switching performance than silicon. Furthermore, in order to increase other switching speeds, it is also possible to use switching elements of compound semiconductors such as gallium arsenide and gallium arsenide aluminum. Further, the above-described failure detection method is an example, and is not limited to that described with reference to FIGS. Other fault detection methods such as ground faults may be used.
　また、上述した各実施形態においては、正極側と負極側の両方を切断する場合について説明したが、検知方法によっては、何れか一方極のみ切断する構成としても良い。 In each of the above-described embodiments, the case of cutting both the positive electrode side and the negative electrode side has been described. However, depending on the detection method, only one of the electrodes may be cut.
　また、上述した各実施形態においては、正極側と負極側の両方に逆流防止ダイオードを使用する構成について説明したが、正極側または負極側の何れか一方極のみに使用する構成としても良い。 Further, in each of the above-described embodiments, the configuration in which the backflow prevention diode is used on both the positive electrode side and the negative electrode side has been described. However, the configuration may be used only on either the positive electrode side or the negative electrode side.
　また、装置構成や制御手法等、本発明の説明に直接必要しない部分等については記載を省略したが、必要とされる装置構成や制御手法を適宜選択して用いることができる。 In addition, although descriptions are omitted for parts that are not directly necessary for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used.
　その他、本発明の要素を具備し、当業者が適宜設計変更しうる全てのスイッチング装置、故障検知装置、太陽光発電システム、及びスイッチング方法は、本発明の範囲に包含される。 In addition, all switching devices, failure detection devices, solar power generation systems, and switching methods that include elements of the present invention and can be appropriately modified by those skilled in the art are included in the scope of the present invention.
　本発明は、スイッチング装置、故障検知装置、太陽光発電システム、及びスイッチング方法に係り、例えば、太陽光発電システム内の太陽電池を切り離すためのスイッチング装置および方法に利用できる。 The present invention relates to a switching device, a failure detection device, a solar power generation system, and a switching method, and can be used for, for example, a switching device and a method for disconnecting a solar cell in the solar power generation system.
６　電圧検出器
８　スイッチ素子
９　検出抵抗
１０　太陽電池モジュール
１２，５０２　太陽電池ストリング
２０，２１，５０４　ダイオード
３０，４０，５０　ＭＯＳＦＥＴ
３１，３３　スイッチング装置
３２，４２，５２　ダイオード部
３４，４４，５４　トランジスタ部
３６　検知部
３８　制御部
８０　スイッチ部
８１　接地電路
８４　抵抗
８２　直流電源
８６　電流計
１００　スイッチ機構
１０２　スイッチング装置
１０４　ゲートドライブ回路
２００　故障検知装置
２０２，２０４，５０８，５０９　接続箱
３００，５０１　太陽電池アレイ
４００，５１０　負荷装置
４０２，４０４，５０６　遮断器
５００　太陽光発電システム
５０３　スイッチ 6 Voltage detector 8 Switch element 9 Detection resistor 10 Solar cell module 12, 502 Solar cell string 20, 21, 504 Diode 30, 40, 50 MOSFET
31, 33 Switching device 32, 42, 52 Diode unit 34, 44, 54 Transistor unit 36 Detection unit 38 Control unit 80 Switch unit 81 Grounding circuit 84 Resistance 82 DC power supply 86 Ammeter 100 Switch mechanism 102 Switching device 104 Gate drive circuit 200 Failure detection device 202, 204, 508, 509 Junction box 300, 501 Solar cell array 400, 510 Load device 402, 404, 506 Breaker 500 Solar power generation system 503 Switch

Claims (11)

  1. 　配線により接続された、太陽電池と前記太陽電池により発電された電力を消費又は変換する負荷装置とを電気的に切り離す開動作と接続する閉動作とを行うスイッチング装置であって、
    　前記配線途中に配置され、ソース及びドレイン間のスイッチングを行うトランジスタ部と前記トランジスタ部のソース及びドレイン間の所定の方向に電流を流すダイオード部とを有する第１の半導体素子を用いて前記配線の開閉を行う開閉部と、
    　前記配線途中で前記第１の半導体素子と直列に配置され、前記第１の半導体素子が有するダイオード部によって流れる電流を遮断する、第２の半導体素子を用いた遮断部と、
    　を備えたことを特徴とするスイッチング装置。     A switching device that performs an opening operation for electrically disconnecting a solar cell and a load device that consumes or converts the power generated by the solar cell and a closing operation that are connected by wiring,
    The first semiconductor element having a transistor portion arranged in the middle of the wiring and switching between a source and a drain and a diode portion for passing a current in a predetermined direction between the source and the drain of the transistor portion is used. An opening and closing part for opening and closing;
    A blocking section using a second semiconductor element, which is arranged in series with the first semiconductor element in the middle of the wiring and blocks a current flowing through a diode section included in the first semiconductor element;
    A switching device comprising:
  2. 　前記第１と第２の半導体素子として、共に、ソース及びドレイン間の所定の方向に電流を流すダイオード部を有するＭＯＳＦＥＴ（Ｍｅｔａｌ　Ｏｘｉｄｅ　Ｓｅｍｉｃｏｎｄｕｃｔｏｒ　Ｆｉｅｌｄ　Ｅｆｆｅｃｔ　Ｔｒａｎｓｉｓｔｏｒ）を用い、
    　前記第１と第２の半導体素子は、それぞれが有する前記ダイオード部が逆向きになるように直列に接続されることを特徴とする請求項１記載のスイッチング装置。     As the first and second semiconductor elements, both MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) having a diode portion for passing a current in a predetermined direction between the source and the drain are used.
    2. The switching device according to claim 1, wherein the first and second semiconductor elements are connected in series so that the diode portions of the first and second semiconductor elements are in opposite directions.
  3. 　前記第１と第２の半導体素子は、ソース側が向き合うように直列に接続されることを特徴とする請求項２記載のスイッチング装置。 3. The switching device according to claim 2, wherein the first and second semiconductor elements are connected in series so that the source sides face each other.
  4. 　前記第１と第２の半導体素子の少なくとも一方に、エンハンスメント型のＭＯＳＦＥＴを用いることを特徴とする請求項１記載のスイッチング装置。 2. The switching device according to claim 1, wherein an enhancement type MOSFET is used for at least one of the first and second semiconductor elements.
  5. 　請求項１記載のスイッチング装置と、
    　前記スイッチング装置によって電気的に切り離された前記太陽電池の故障を検知する検知部と、
    　を備えたことを特徴とする太陽電池の故障検知装置。     A switching device according to claim 1;
    A detection unit for detecting a failure of the solar cell electrically disconnected by the switching device;
    A failure detection device for a solar cell, comprising:
  6. 　前記第１と第２の半導体素子として、共に、ソース及びドレイン間の所定の方向に電流を流すダイオード部を有するＭＯＳＦＥＴ（Ｍｅｔａｌ　Ｏｘｉｄｅ　Ｓｅｍｉｃｏｎｄｕｃｔｏｒ　Ｆｉｅｌｄ　Ｅｆｆｅｃｔ　Ｔｒａｎｓｉｓｔｏｒ）を用い、
    　前記第１と第２の半導体素子は、それぞれが有する前記ダイオード部が逆向きになるように直列に接続されることを特徴とする請求項５記載の太陽電池の故障検知装置。     As the first and second semiconductor elements, both MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) having a diode portion for passing a current in a predetermined direction between the source and the drain are used.
    6. The solar cell failure detection device according to claim 5, wherein the first and second semiconductor elements are connected in series so that the diode portions of the first and second semiconductor elements are in opposite directions.
  7. 　前記第１と第２の半導体素子は、ソース側が向き合うように直列に接続されることを特徴とする請求項６記載の太陽電池の故障検知装置。 The solar cell failure detection device according to claim 6, wherein the first and second semiconductor elements are connected in series so that the source sides face each other.
  8. 　前記第１と第２の半導体素子の少なくとも一方に、エンハンスメント型のＭＯＳＦＥＴを用いることを特徴とする請求項５記載の太陽電池の故障検知装置。 6. The solar cell failure detection apparatus according to claim 5, wherein an enhancement type MOSFET is used for at least one of the first and second semiconductor elements.
  9. 　複数の太陽電池モジュールを直列に接続した複数の太陽電池ストリングを並列に接続した太陽電池アレイと、
    　前記複数の太陽電池ストリングとそれぞれ配線によって接続され、前記複数の太陽電池ストリングにより発電された電力を消費又は変換する負荷装置と、
    　太陽電池ストリング毎の前記配線の正極側と負極側の少なくとも一方の途中にそれぞれ配置され、ソース及びドレイン間のスイッチングを行うトランジスタ部と前記トランジスタ部のソース及びドレイン間の所定の方向に電流を流すダイオード部とを有する第１の半導体素子を用いて前記配線の前記少なくとも一方の開閉を行う開閉部と、
    　太陽電池ストリング毎の前記配線の前記少なくとも一方の途中で前記第１の半導体素子と直列にそれぞれ配置され、前記第１の半導体素子が有するダイオード部によって流れる電流を遮断する、第２の半導体素子を用いた遮断部と、
    　を備えたことを特徴とする太陽光発電システム。     A solar cell array in which a plurality of solar cell strings in which a plurality of solar cell modules are connected in series are connected in parallel;
    A load device connected to each of the plurality of solar cell strings by wiring and consuming or converting the power generated by the plurality of solar cell strings;
    A transistor part that is arranged in the middle of at least one of the positive electrode side and the negative electrode side of the wiring for each solar cell string, and allows current to flow in a predetermined direction between the source and drain of the transistor part An opening / closing part for opening / closing at least one of the wirings using a first semiconductor element having a diode part;
    A second semiconductor element arranged in series with the first semiconductor element in the middle of the at least one of the wirings for each solar cell string, and blocking a current flowing through a diode portion included in the first semiconductor element; The blocking part used,
    A photovoltaic power generation system characterized by comprising:
  10. 　前記第１と第２の半導体素子として、共に、ソース及びドレイン間の所定の方向に電流を流すダイオード部を有する、デプレション型のＭＯＳＦＥＴ（Ｍｅｔａｌ　Ｏｘｉｄｅ　Ｓｅｍｉｃｏｎｄｕｃｔｏｒ　Ｆｉｅｌｄ　Ｅｆｆｅｃｔ　Ｔｒａｎｓｉｓｔｏｒ）を用い、
    　前記第１と第２の半導体素子は、それぞれが有する前記ダイオード部が逆向きになるように直列に接続され、
    　前記第１と第２の半導体素子のそれぞれの前記トランジスタ部を駆動する電源は、前記複数の太陽電池ストリングと前記負荷装置とを接続する配線から供給されることを特徴とする請求項９記載の太陽光発電システム。     As the first and second semiconductor elements, both use a depletion type MOSFET (Metal Oxide Field Effect Transistor) having a diode part for passing a current in a predetermined direction between the source and the drain,
    The first and second semiconductor elements are connected in series so that the diode portions included in each of the first and second semiconductor elements are opposite to each other,
    10. The power source for driving each of the transistor portions of the first and second semiconductor elements is supplied from a wiring connecting the plurality of solar cell strings and the load device. Solar power system.
  11. 　配線により接続された、太陽電池と前記太陽電池により発電された電力を消費又は変換する負荷装置とを電気的に切り離す開動作と接続する閉動作とを行うスイッチング方法であって、
    　前記配線途中に配置され、ソース及びドレイン間のスイッチングを行うトランジスタ部と前記トランジスタ部のソース及びドレイン間の所定の方向に電流を流すダイオード部とを有する第１の半導体素子を用いて前記配線の開動作を行い、
    　前記配線途中で前記第１の半導体素子と直列に配置された第２の半導体素子を用いて、前記第１の半導体素子によって前記配線が開に制御された状態において、前記第１の半導体素子が有するダイオード部によって流れる電流を遮断することを特徴とするスイッチング方法。     A switching method that performs an opening operation for electrically disconnecting a solar cell and a load device that consumes or converts the power generated by the solar cell and a closing operation that are connected by wiring;
    The first semiconductor element having a transistor portion arranged in the middle of the wiring and switching between a source and a drain and a diode portion for passing a current in a predetermined direction between the source and the drain of the transistor portion is used. Perform the opening operation,
    In the state where the wiring is controlled to be opened by the first semiconductor element using the second semiconductor element arranged in series with the first semiconductor element in the middle of the wiring, the first semiconductor element is The switching method characterized by interrupting the electric current which flows by the diode part which has.
PCT/JP2014/053893 2013-04-18 2014-02-19 Switching device, failure detection device, solar power system, and switching method WO2014171176A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2013-087730 2013-04-18
JP2013087730A JP2014212212A (en) 2013-04-18 2013-04-18 Switching device, fault detector, photovoltaic power generation system, and switching method

Publications (1)

Publication Number Publication Date
WO2014171176A1 true WO2014171176A1 (en) 2014-10-23

Family

ID=51731137

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2014/053893 WO2014171176A1 (en) 2013-04-18 2014-02-19 Switching device, failure detection device, solar power system, and switching method

Country Status (2)

Country Link
JP (1) JP2014212212A (en)
WO (1) WO2014171176A1 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104702209A (en) * 2015-03-31 2015-06-10 阿特斯(中国)投资有限公司 Detection method of solar battery pieces
CN104883122A (en) * 2015-06-02 2015-09-02 江苏四叶草新能源科技有限公司 Distributed photovoltaic grid-connected intelligent protector with function of automatic switching-on after the existence of voltage is detected
JP2018143047A (en) * 2017-02-28 2018-09-13 国立大学法人岐阜大学 Device and method for recovering performance deterioration of solar cell
CN109600115A (en) * 2017-09-30 2019-04-09 丰郅(上海)新能源科技有限公司 The method of positioning failure in the photovoltaic generating system of tandem type
TWI668935B (en) * 2018-10-31 2019-08-11 國立勤益科技大學 System and method for fault diagnosis in photovoltaic module arrays
CN113708721A (en) * 2016-04-05 2021-11-26 太阳能安吉科技有限公司 Safety switch for photovoltaic system
RU2763045C1 (en) * 2021-03-12 2021-12-27 Акционерное общество «Информационные спутниковые системы» имени академика М.Ф.Решетнёва» Method for over-current protection of power key failure in response to short circuit

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104660038A (en) * 2015-03-09 2015-05-27 中利腾晖光伏科技有限公司 Intelligent solar photovoltaic module circuit and control/protection method thereof
JP2017055255A (en) * 2015-09-09 2017-03-16 株式会社東芝 Power semiconductor device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11215835A (en) * 1998-01-26 1999-08-06 Kumamoto Prefecture Driving circuit for non-grounded semiconductor switch for power
JP2007116653A (en) * 2005-09-20 2007-05-10 Denso Corp Switching circuit
JP2010080548A (en) * 2008-09-24 2010-04-08 Sekisui Chem Co Ltd Solar photovoltaic power generation module
WO2010119526A1 (en) * 2009-04-15 2010-10-21 三菱電機株式会社 Inverter device, electric motor drive device, refrigeration/air-conditioning device, and electric power generation system
JP2012054694A (en) * 2010-08-31 2012-03-15 On Semiconductor Trading Ltd Bidirectional switch and switch circuit using the same
JP2012129729A (en) * 2010-12-14 2012-07-05 Panasonic Corp Electronic relay
JP2013033825A (en) * 2011-08-01 2013-02-14 Jx Nippon Oil & Energy Corp Ground fault detection device, ground fault detection method, photovoltaic power generation system, and ground fault detection program

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11215835A (en) * 1998-01-26 1999-08-06 Kumamoto Prefecture Driving circuit for non-grounded semiconductor switch for power
JP2007116653A (en) * 2005-09-20 2007-05-10 Denso Corp Switching circuit
JP2010080548A (en) * 2008-09-24 2010-04-08 Sekisui Chem Co Ltd Solar photovoltaic power generation module
WO2010119526A1 (en) * 2009-04-15 2010-10-21 三菱電機株式会社 Inverter device, electric motor drive device, refrigeration/air-conditioning device, and electric power generation system
JP2012054694A (en) * 2010-08-31 2012-03-15 On Semiconductor Trading Ltd Bidirectional switch and switch circuit using the same
JP2012129729A (en) * 2010-12-14 2012-07-05 Panasonic Corp Electronic relay
JP2013033825A (en) * 2011-08-01 2013-02-14 Jx Nippon Oil & Energy Corp Ground fault detection device, ground fault detection method, photovoltaic power generation system, and ground fault detection program

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104702209A (en) * 2015-03-31 2015-06-10 阿特斯(中国)投资有限公司 Detection method of solar battery pieces
CN104883122A (en) * 2015-06-02 2015-09-02 江苏四叶草新能源科技有限公司 Distributed photovoltaic grid-connected intelligent protector with function of automatic switching-on after the existence of voltage is detected
CN104883122B (en) * 2015-06-02 2017-12-05 江苏四叶草新能源科技有限公司 There is the grid-connected intellective protector of distributed photovoltaic of pressure automatic switching-in function with inspection
CN113708721A (en) * 2016-04-05 2021-11-26 太阳能安吉科技有限公司 Safety switch for photovoltaic system
JP2018143047A (en) * 2017-02-28 2018-09-13 国立大学法人岐阜大学 Device and method for recovering performance deterioration of solar cell
CN109600115A (en) * 2017-09-30 2019-04-09 丰郅(上海)新能源科技有限公司 The method of positioning failure in the photovoltaic generating system of tandem type
CN109600115B (en) * 2017-09-30 2020-12-29 丰郅(上海)新能源科技有限公司 Method for locating faults in series-connected photovoltaic power generation system
TWI668935B (en) * 2018-10-31 2019-08-11 國立勤益科技大學 System and method for fault diagnosis in photovoltaic module arrays
RU2763045C1 (en) * 2021-03-12 2021-12-27 Акционерное общество «Информационные спутниковые системы» имени академика М.Ф.Решетнёва» Method for over-current protection of power key failure in response to short circuit

Also Published As

Publication number Publication date
JP2014212212A (en) 2014-11-13

Similar Documents

Publication Publication Date Title
WO2014171176A1 (en) Switching device, failure detection device, solar power system, and switching method
CN109075782B (en) Junction temperature and current sensing
US9673744B2 (en) Operating state circuit for inverter and method for setting operating states of an inverter
US9252682B2 (en) Grid-connected inverter apparatus and control method therefor
US9887650B2 (en) Inverter device and power steering device
US9874614B2 (en) Semiconductor apparatus and power conversion apparatus
US9124103B2 (en) Electrical storage apparatus
US9755630B2 (en) Solid-state circuit breakers and related circuits
US8729739B2 (en) Bi-directional circuit breaker
US11183835B2 (en) Short circuit detection and protection for a gate driver circuit and methods of detecting the same using logic analysis
EP2755314B1 (en) Switch driving circuit, inverter apparatus and power steering apparatus
US9698769B2 (en) Semiconductor device
US20140373895A1 (en) Solar cell unit and solar cell module
JP2018072155A (en) Semiconductor switch control apparatus
JP2019165347A (en) Drive device and power module
WO2015015835A1 (en) Solar power generation system
WO2016194487A1 (en) Power conversion device and motor device
JP2007312480A (en) Three-phase inverter circuit
WO2015092522A1 (en) Drive control apparatus for semiconductor device
KR102377401B1 (en) Apparatus for detecting short circuit of power semiconductor device and power semiconductor system
WO2022264314A1 (en) Motor drive device calculating insulation resistance value of motor
US11742653B2 (en) Integrated circuit module for circuit breakers, relays and contactors
KR100625214B1 (en) Insulated gate bipolar transistor with protecting circuit
Lu et al. Design of over-current protection circuit for power transistors
KR20170009344A (en) A power conversion device with short circuit protection circuit

Legal Events

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

Ref document number: 14785794

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: 14785794

Country of ref document: EP

Kind code of ref document: A1