WO2022016919A1 - 一种电压补偿装置、逆变装置及光伏发电系统 - Google Patents

一种电压补偿装置、逆变装置及光伏发电系统 Download PDF

Info

Publication number
WO2022016919A1
WO2022016919A1 PCT/CN2021/087595 CN2021087595W WO2022016919A1 WO 2022016919 A1 WO2022016919 A1 WO 2022016919A1 CN 2021087595 W CN2021087595 W CN 2021087595W WO 2022016919 A1 WO2022016919 A1 WO 2022016919A1
Authority
WO
WIPO (PCT)
Prior art keywords
inverter
power
coupled
voltage compensation
input terminal
Prior art date
Application number
PCT/CN2021/087595
Other languages
English (en)
French (fr)
Inventor
王勋
Original Assignee
华为数字能源技术有限公司
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 华为数字能源技术有限公司 filed Critical 华为数字能源技术有限公司
Priority to EP21845320.7A priority Critical patent/EP4184743A4/en
Publication of WO2022016919A1 publication Critical patent/WO2022016919A1/zh
Priority to US18/156,558 priority patent/US20230155382A1/en

Links

Images

Classifications

    • 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
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
    • H02S40/30—Electrical components
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
    • 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
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
    • H02S40/30—Electrical components
    • H02S40/32—Electrical components comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules
    • 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
    • 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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation

Definitions

  • the present application relates to the field of photovoltaic power generation, and in particular, to a voltage compensation device, an inverter device and a photovoltaic power generation system.
  • the photovoltaic panel string is the main component of the photovoltaic power generation system (PV Generator System).
  • the photovoltaic panel string is prone to the Potential Induced Degradation (PID) effect in a humid environment.
  • PID Potential Induced Degradation
  • the PID effect of the photovoltaic panel string That is, the bias voltage that exists in the photovoltaic panel string to the ground, and the phenomenon of power attenuation occurs under the action of the bias voltage.
  • the PID effect of the photovoltaic panel string will seriously attenuate the power of the photovoltaic panel string, thereby affecting the power output of the entire power station. Therefore, reducing the PID effect of the photovoltaic panel string has a very important impact on the photovoltaic panel string. important.
  • the compensation loop can be used to repair the PID effect of the photovoltaic panel string, and a voltage compensation device is built inside the inverter of the photovoltaic power generation system.
  • the voltage compensation device is used to obtain electricity from the power grid, and the compensation voltage is output between the PV panel string and the protective conductor (Protecting Earth, PE), so as to repair the PID effect of the PV panel string.
  • PE Protected Earth
  • the power input terminal of the voltage compensation device is coupled and connected to the power grid, one pole of the power output terminal of the voltage compensation device is coupled and connected to the photovoltaic panel string, and the other pole of the power output terminal of the power conversion module is connected to the external casing of the inverter. Coupling connection, and then realize the coupling connection with PE through the external casing of the inverter.
  • the passage between the voltage compensation device and the external casing of the inverter, and the passage between the external casing of the inverter and the PE form a compensation loop to compensate for the bias voltage between the PV panel string and the PE.
  • the voltage attenuation of the PV panel string is compensated, so as to repair the PID effect of the PV panel string.
  • the PE and the external casing of the inverter are two independent components, it is necessary to set a wiring between the PE and the external casing of the inverter to realize the electrical coupling connection between the two.
  • the wiring between the external casing of the inverter and the PE is usually done manually, which is prone to problems such as missing connections or low wiring quality (poor contact).
  • the present application provides a voltage compensation device, an inverter device and a photovoltaic power generation system to solve the problem of poor repair quality of the PID effect of the existing photovoltaic panels.
  • an embodiment of the present invention provides a voltage compensation device, including a power conversion module, wherein the power conversion module is coupled and connected to an electric energy input terminal of the voltage compensation device and an electric energy output terminal of the voltage compensation device, respectively.
  • the power input terminal of the voltage compensation device is coupled and connected to the power grid for obtaining power from the power grid; one pole of the power output terminal of the voltage compensation device is coupled to the power output terminal of the photovoltaic panel string, and/or an inverter the power input terminal of the inverter, and/or the power input terminal of the inverter unit in the inverter, and/or the loop between the power input terminal of the inverter and the power input terminal of the inverter unit,
  • the other pole of the power output terminal of the voltage compensation device is coupled to the N line of the power grid, and is used to apply the power obtained from the power grid between the power output terminal of the photovoltaic cell panel string and the ground.
  • the voltage compensation device can take power from the grid, and then compensate the bias voltage consumed by the photovoltaic panel string to the ground, thereby restoring the power that appears in the photovoltaic panel string. attenuation phenomenon.
  • the power output terminal of the voltage compensation device is directly coupled to the N pole of the power grid to form a power compensation loop, it is not necessary to rely on the ground wire of the inverter to form a power compensation loop. Therefore, even if the ground wire of the inverter is missed or When the wiring quality is low, voltage compensation can still be performed on the PV panel string, and the risk of electric shock to personnel can be avoided.
  • the power input terminal of the voltage compensation device is coupled to connect the grid-connected switch unit in the inverter with the inverter circuit between the power output terminals of the device.
  • the power input terminal of the voltage compensation device is coupled to the power output terminal of the inverter or is coupled to the power output terminal of the inverter. Grid external to the inverter.
  • the voltage compensating device can select an appropriate power-taking and wiring mode according to the location where it is set.
  • the power input terminals of the voltage compensation device are respectively coupled and connected to at least one phase of the ABC phase of the power grid and the N line of the power grid; or, the power input terminals of the voltage compensation device are connected to all At least two phases in the ABC phase of the power grid; or, the power input terminal of the voltage compensation device is coupled to connect the L phase of the power grid and the N line of the power grid.
  • the voltage compensation device can select the L phase that is coupled and connected to the power grid according to the type of the power grid and the actual needs, or, one phase, two phases, and three phases of the ABC phase to obtain voltage, which can be the connection method of the voltage compensation device. Provide more options.
  • the positive electrode of the power output terminal of the voltage compensation device is coupled to the power output terminal of the photovoltaic cell panel string, and and/or the power input terminal of the inverter, and/or the power input terminal of the inverter unit in the inverter, and/or the power input terminal of the inverter and the power input terminal of the inverter unit.
  • the loop between the power input terminals, the negative pole of the power output terminal of the voltage compensation device is coupled to the N line of the power grid; or, if the compensation voltage corresponding to the photovoltaic panel string is a negative voltage, the The negative pole of the power output terminal of the voltage compensation device is coupled to the power output terminal of the photovoltaic panel string, and/or the power input terminal of the inverter, and/or the power input terminal of the inverter unit in the inverter.
  • the power input terminal, and/or the loop between the power input terminal of the inverter and the power input terminal of the inverter unit, the positive pole of the power output terminal of the voltage compensation device is coupled to the N line of the power grid .
  • the correct wiring method can be selected according to the type of voltage that the PV panel string actually needs to compensate for, thereby improving the effect of voltage compensation.
  • the power conversion module is an isolated AC/DC conversion unit.
  • the coupling connection is at least one of a direct coupling connection, a coupling connection through a switching device, a coupling connection through a current limiting component, and a coupling connection through a switching device and a current limiting component.
  • the switching device is one or a combination of semiconductor switches, relays, contactors, circuit breakers, and mechanical switches.
  • suitable switching devices can be selected according to actual needs, such as cost, safety rules, and the like.
  • the current limiting component is a resistor, an inductor or a current limiting circuit.
  • an embodiment of the present invention provides an inverter device, the inverter device includes: an inverter and the voltage compensation device described in the first aspect; the inverter includes a housing, an electric energy input terminal , an electric energy output terminal, an inverter unit and a grid-connected switch unit; the electric energy input terminal and the electric energy output terminal are arranged on the casing, and the electric energy input terminal is used for coupling and connecting the electric energy output terminal of the photovoltaic panel string , the power output terminal is used for coupling and connection to the power grid; the inverter unit, the grid-connected switch unit and the voltage compensation device are all arranged inside the inverter; the power input end of the inverter unit The power input terminal is coupled and connected; the power output terminal of the inverter unit is coupled and connected to the power output terminal through the grid-connected switch unit; the power input terminal of the voltage compensation device is coupled to the grid-connected switch unit and A loop between the power output terminals; one pole of the power output terminal of the voltage compensation device is coupled
  • the inverter can be used in a photovoltaic power generation system, and the inverter can simultaneously convert the direct current sent by the photovoltaic panel string into alternating current and compensate the voltage of the photovoltaic panel string, wherein the voltage compensation device One pole of the power output terminal is coupled to the N line of the power grid to achieve grounding without relying on the grounding line of the inverter itself to form a voltage compensation loop. Therefore, even if the ground wire of the inverter is leaked or the wiring quality is low, the voltage compensation of the PV panel string can still be performed, and the risk of electric shock to personnel can be avoided.
  • the positive electrode of the power output terminal of the voltage compensation device is coupled to the power input terminal of the inverter, and/ or the power input terminal of the inverter unit in the inverter, and/or the loop between the power input terminal of the inverter and the power input terminal of the inverter unit, the power of the voltage compensation device
  • the negative pole of the output terminal is coupled to a power output terminal coupled to the N line of the power grid, and/or coupled to a coupling loop corresponding to the power output terminal coupled to the N line of the power grid in the inverter;
  • the compensation voltage corresponding to the photovoltaic panel string is a negative voltage
  • the negative electrode of the power output terminal of the voltage compensation device is coupled to the power input terminal of the inverter, and/or the inverter
  • the voltage compensating device can select an appropriate power-taking and wiring mode according to the location where it is set.
  • the power input terminals of the voltage compensation device are respectively coupled and connected to at least one phase of the ABC phase of the power grid and the N line of the power grid; or, the power input terminals of the voltage compensation device are connected to all At least two phases in the ABC phase of the power grid; or, the power input terminal of the voltage compensation device is coupled to connect the L phase of the power grid and the N line of the power grid.
  • the voltage compensation device can select the L phase that is coupled and connected to the power grid according to the type of the power grid and the actual needs, or, one phase, two phases, and three phases of the ABC phase to obtain voltage, which can be the connection method of the voltage compensation device. Provide more options.
  • the inverter further includes a DC/DC DC transformation unit; an input terminal of the DC/DC DC transformation unit is coupled to the power input terminal; the DC/DC DC transformation unit is coupled to the power input terminal; The output terminal of the unit is coupled to the input terminal of the inverter unit.
  • the DC/DC direct current transformer unit can convert the inverted direct current into a voltage that conforms to the voltage used on the string side of the photovoltaic panel.
  • the voltage compensation device includes a power conversion module; the power conversion module is respectively coupled to the power input terminal of the voltage compensation device and the power output terminal of the voltage compensation device; wherein the power The conversion module isolates the AC/DC conversion unit.
  • the voltage compensation device can access the voltage from the power grid through the power input terminal, transmit the connected voltage to the photovoltaic panel string through the power conversion module, and finally connect the power output terminal to the N line of the power grid to achieve a voltage
  • the compensation loop compensates the voltage for the photovoltaic panel string, and converts the AC voltage into a DC voltage.
  • the coupling connection is at least one of a direct coupling connection, a coupling connection through a switching device, a coupling connection through a current limiting component, and a coupling connection through a switching device and a current limiting component.
  • the switching device is one or a combination of semiconductor switches, relays, contactors, circuit breakers, and mechanical switches.
  • suitable switching devices can be selected according to actual needs, such as cost, safety rules, and the like.
  • the current limiting component is a resistor, an inductor or a current limiting circuit.
  • the inverter further includes a control unit; the control unit is respectively connected with the inverter unit, the DC/DC conversion unit, the grid-connected switch unit and the voltage compensation device Coupling connection.
  • control unit can realize the automatic control of the inverter unit, the DC/DC direct current conversion unit, the grid-connected switch unit and the voltage compensation device, thereby improving the control accuracy of the inverter.
  • an embodiment of the present invention provides a photovoltaic power generation system
  • the photovoltaic power generation system includes: a photovoltaic cell panel string and an inverter device, the inverter device includes an inverter and is as described in the first aspect
  • the power output terminal of the photovoltaic panel string is coupled to the power input terminal of the inverter; the power output terminal of the inverter is coupled to the power grid; the power input terminal of the voltage compensation device
  • the power grid is coupled and connected to obtain power from the power grid; one pole of the power output terminal of the voltage compensation device is coupled to the power output terminal of the photovoltaic panel string, and/or the power output terminal of the inverter.
  • the other pole of the power output terminal of the voltage compensation device is coupled to the N line of the power grid for applying the power obtained from the power grid between the power output terminal of the photovoltaic panel string and the ground.
  • the voltage compensation device can take power from the grid, and then compensate the bias voltage consumed by the photovoltaic panel string to the ground, thereby restoring the power that appears in the photovoltaic panel string. attenuation phenomenon.
  • the power output terminal of the voltage compensation device is directly coupled to the N pole of the power grid to form a power compensation loop, it is not necessary to rely on the ground wire of the inverter to form a power compensation loop. Therefore, even if the ground wire of the inverter is missed or When the wiring quality is low, voltage compensation can still be performed on the PV panel string, and the risk of electric shock to personnel can be avoided.
  • the power input terminal of the voltage compensation device is coupled to connect the grid-connected switch unit in the inverter with the inverter If the voltage compensation device is arranged outside the inverter, the power input terminal of the voltage compensation device is coupled to the power output terminal of the inverter or coupled to the grid external to the inverter.
  • the voltage compensating device can select an appropriate power-taking and wiring mode according to the location where it is set.
  • the power input terminals of the voltage compensation device are respectively coupled and connected to at least one phase of the ABC phase of the power grid and the N line of the power grid; or, the power input terminals of the voltage compensation device are coupled and connected At least two phases in the ABC phase of the power grid; or, the power input terminal of the voltage compensation device is coupled to connect the L phase of the power grid and the N line of the power grid.
  • the voltage compensation device can select the L phase that is coupled and connected to the power grid according to the type of the power grid and the actual needs, or, one phase, two phases, and three phases of the ABC phase to obtain voltage, which can be the connection method of the voltage compensation device. Provide more options.
  • the positive electrode of the power output terminal of the voltage compensation device is coupled to the power output terminal of the photovoltaic cell panel string, and and/or the power input terminal of the inverter, and/or the power input terminal of the inverter unit in the inverter, and/or the power input terminal of the inverter and the power input terminal of the inverter unit.
  • the loop between the power input terminals, the negative pole of the power output terminal of the voltage compensation device is coupled to the N line of the power grid; or, if the compensation voltage corresponding to the photovoltaic panel string is a negative voltage, the The negative pole of the power output terminal of the voltage compensation device is coupled to the power output terminal of the photovoltaic panel string, and/or the power input terminal of the inverter, and/or the power input terminal of the inverter unit in the inverter.
  • the power input terminal, and/or the loop between the power input terminal of the inverter and the power input terminal of the inverter unit, the positive pole of the power output terminal of the voltage compensation device is coupled to the N line of the power grid .
  • the correct wiring method can be selected according to the type of voltage that the PV panel string actually needs to compensate for, thereby improving the effect of voltage compensation.
  • the voltage compensation device includes a power conversion module; the power conversion module is respectively coupled to the power input terminal of the voltage compensation device and the power output terminal of the voltage compensation device; wherein the power The conversion module is an isolated AC/DC conversion unit.
  • the voltage compensation device can access the voltage from the power grid through the power input terminal, transmit the connected voltage to the photovoltaic panel string through the power conversion module, and finally connect the power output terminal to the N line of the power grid to achieve a voltage
  • the compensation loop compensates the voltage for the photovoltaic panel string and converts the AC voltage into a DC voltage.
  • the coupling connection is a direct coupling connection, a coupling connection through a switching device, a coupling connection through a current limiting component, or a coupling connection through a switching device and a current limiting component.
  • the switching device is one or a combination of semiconductor switches, relays, contactors, circuit breakers, and mechanical switches.
  • suitable switching devices can be selected according to actual needs, such as cost, safety rules, and the like.
  • the current limiting component is a resistor, an inductor or a current limiting circuit.
  • the system further includes a controller; the controller is coupled and communicated with the inverter and the voltage compensation device, respectively, for enabling the inverter and the voltage compensation device and off.
  • the controller can realize the automatic control of the inverter and the voltage compensation device, thereby improving the control accuracy of the voltage compensation process.
  • Figure 1 is a schematic structural diagram of a photovoltaic power generation system
  • FIG. 2 is a schematic diagram of a voltage compensation loop
  • FIG. 3 is a schematic diagram of a human body contact
  • FIG. 4 is a schematic structural diagram of a photovoltaic power generation system according to an embodiment of the present invention.
  • FIG. 5 is a schematic structural diagram of obtaining electric energy by coupling and connecting two phases in an ABC-phase power grid according to an embodiment of the present invention
  • FIG. 6 is a schematic structural diagram of obtaining electric energy by coupling and connecting three phases in an ABC-phase power grid according to an embodiment of the present invention
  • FIG. 7 is a schematic structural diagram of obtaining electric energy from a LN phase power grid by coupling and connecting according to an embodiment of the present invention
  • FIG. 8 is a schematic structural diagram of a photovoltaic power generation system according to an embodiment of the present invention.
  • FIG. 9 is a schematic structural diagram of a photovoltaic power generation system according to an embodiment of the present invention.
  • FIG. 10 is a schematic structural diagram of an inverter device according to an embodiment of the present invention.
  • FIG. 11 is a schematic structural diagram of an inverter device according to an embodiment of the present invention.
  • FIG. 12 is a schematic structural diagram of an inverter device according to an embodiment of the present invention.
  • FIG. 13 is a schematic diagram of the internal structure of a single-phase inverter according to an embodiment of the present invention.
  • FIG. 14 is a schematic diagram of an internal structure of a power conversion module provided by an embodiment of the present invention.
  • 15 is a schematic diagram of an internal structure of a power conversion module provided by an embodiment of the present invention.
  • 16 is a schematic diagram of an internal structure of a power conversion module provided by an embodiment of the present invention.
  • FIG. 17 is a schematic structural diagram of a photovoltaic power generation system with a controller provided by an embodiment of the present invention.
  • FIG. 18 is a schematic structural diagram of an inverter with a control unit according to an embodiment of the present invention.
  • 1- photovoltaic panel string 11- voltage divider circuit, 2- inverter, 21- inverter unit, 22- shell, 23- grid-connected switch unit, 24- power input terminal, 25- power output terminal , 26-DC/DC DC transformer unit, 3-voltage compensation device, 31-power conversion module, 32-power input terminal, 33-power output terminal, 4-power grid, 5-controller, 6-control unit, 7 -Inverter device.
  • FIG. 1 is a schematic structural diagram of a photovoltaic power generation system.
  • the photovoltaic power generation system includes a photovoltaic panel string 1 and an inverter device 7.
  • the inverter device 7 includes an inverter 2 and a voltage compensation device 3, wherein , the power output terminal of the photovoltaic panel string 1 is coupled to the power input terminal of the inverter 2, so that the photovoltaic panel string 1 can transmit the generated DC power to the inverter 2, and at the same time, the photovoltaic panel string 1
  • the negative pv- of the power output terminal is grounded.
  • the inverter 2 can use an inverter unit 21, such as a direct current/alternating current (DC/AC) conversion unit, to convert the received direct current into alternating current that meets the requirements of the grid.
  • the power output terminal of the inverter 2 It is coupled and connected to the power grid 4, so that the inverter 2 can transmit the converted alternating current to the power grid 4, and then the power grid 4 transmits the alternating current to each power unit.
  • the inverter 2 can also be grounded through the casing 22. to ensure safe use.
  • the photovoltaic array formed by the series-parallel structure of each photovoltaic module in the photovoltaic panel string 1 causes parasitic capacitance and impedance between the power output terminal of the photovoltaic panel string 1 and the ground, that is, the PID effect is generated.
  • Capacitance C- and parasitic impedance R- Capacitance C- and parasitic impedance R-.
  • parasitic capacitances and impedances play a role in dividing the voltage of the photovoltaic panel string 1 , and these parasitic capacitances and parasitic impedances can be represented by the voltage dividing circuit 11 in FIG. 1 . It is precisely because of the existence of the voltage divider circuit that the photovoltaic panel string 1 will generate a bias voltage to the ground, so that the photovoltaic panel string 1 will experience power attenuation under the action of the bias voltage, that is, PID In order to reduce the impact of the PID effect on the photovoltaic panel string 1, the voltage compensation device 3 can be used to perform voltage compensation on the bias voltage between the power output terminal of the photovoltaic panel string 1 and the ground, thereby reducing the PID effect. Influence.
  • the voltage compensation device 3 is arranged in the inverter 2 , and the power input terminal of the voltage compensation device 3 is coupled and connected to the power grid 4 .
  • the voltage compensation device 3 starts to draw power from grid 4.
  • One pole of the power output terminal of the voltage compensation device 3 is coupled and connected to one side of the photovoltaic cell panel string 1.
  • one pole of the power output terminal of the voltage compensation device 3 is connected to the power input terminal of the inverter 2 and the inverter unit.
  • the loop between the input terminals of 21 is taken as an example.
  • the other pole of the power output terminal of the voltage compensation device 3 is grounded through the casing 22.
  • FIG. 2 is a schematic diagram of a voltage compensation loop, as indicated by the thicker dotted line in FIG.
  • the path between the voltage compensation device 3 and the voltage divider circuit 11, the voltage divider circuit 11, PE, the path between the voltage compensation device 3 and the casing 22 of the inverter 2, the casing 22 of the inverter 2 and the PE forms a voltage compensation loop, so that the compensation voltage is applied between the power output terminal of the photovoltaic panel string 1 and the PE to compensate the bias voltage.
  • the voltage compensation device 3 wants to realize voltage compensation for the bias voltage, the grounding quality of the casing 22 of the inverter 2 must be ensured.
  • the voltage compensation loop will be disconnected, so that the voltage compensation device 3 cannot perform voltage compensation on the bias voltage, and the influence of the PID effect on the photovoltaic panel string 1 cannot be solved.
  • the casing 22 will be grounded by the human body.
  • the PE in the voltage compensation circuit is connected to the casing 22 of the inverter 2. It is connected through the human body, and the current passes through the human body, which will cause great harm to people.
  • the method of realizing the grounding of the voltage compensation module 3 through the inverter 2 to form a voltage compensation loop may cause the failure of the voltage compensation loop or cause the problem of personal safety hazards.
  • the present invention provides the following methods:
  • An embodiment of the present invention provides a photovoltaic power generation system, the system includes: a photovoltaic cell panel string and an inverter device, the inverter device includes an inverter and a voltage compensation device; an electric energy output terminal of the photovoltaic cell panel string The power input terminal of the inverter is coupled and connected; the power output terminal of the inverter is coupled and connected to the grid; the power input terminal of the voltage compensation device is coupled and connected to the grid for obtaining power from the grid; One pole of the power output terminal of the voltage compensation device is coupled to the power output terminal of the photovoltaic cell panel string, and/or the power input terminal of the inverter, and/or the inverter in the inverter.
  • the power input terminal of the unit, and/or the loop between the power input terminal of the inverter and the power input terminal of the inverter unit, the other pole of the power output terminal of the voltage compensation device is coupled to connect the
  • the N line of the power grid is used to apply the power obtained from the power grid between the power output terminal of the photovoltaic panel string and the ground.
  • FIG. 4 is a schematic structural diagram of a photovoltaic power generation system provided by an embodiment of the present invention. As shown in FIG. 4 , in this embodiment, in the inverter device 7 , the inverter 2 and the voltage compensation device 3 are two independent The device, the voltage compensation device 3 is arranged outside the inverter 2 .
  • One pole of the power output terminal of the voltage compensation device 3 can be grounded by being coupled to the N line of the power grid 4, and the other pole of the power output terminal of the voltage compensation device 3 can be coupled to the power output terminal of the photovoltaic panel string 1, and/ or the power input terminal of the inverter 2, and/or the power input terminal of the inverter unit 21 in the inverter 2, and/or the power input terminal of the inverter 2 and the inverter The loop between the power inputs of the unit 21.
  • the other pole of the power output terminal of the voltage compensation device 3 may only be coupled and connected to the power output terminal of the photovoltaic panel string 1 , the power input terminal of the inverter 2 , and the inverter in the inverter 2 .
  • FIG. 4 takes the positive electrode of the power output terminal of the voltage compensation device 3 coupled to the power input terminal of the photovoltaic cell panel string 1 as an example.
  • the power input terminal of the photovoltaic cell panel string 1 includes the device of the power input terminal. and the loop between the device and the power input terminals of the inverter 2 .
  • the path between the positive electrode of the power output terminal of the voltage compensation device 3 and the power output terminal of the photovoltaic panel string 1 , the voltage divider circuit 11 , PE, and the voltage compensation device 3 The path between the negative pole of the power output terminal and the N line, and the path between the N line and PE form a voltage compensation loop.
  • the voltage compensation device 3 After the voltage compensation device 3 obtains the power from the power grid 4, the obtained power can be passed through the voltage compensation loop. It is applied between the power output terminal of the photovoltaic panel string 1 and PE, so as to realize the voltage compensation of the bias voltage between the power output terminal of the photovoltaic panel string 1 and the PE, thereby reducing the PID effect on the photovoltaic panel group.
  • the power output terminal of the voltage compensation device 3 is grounded by coupling with the N line of the power grid 4, so it is not necessary to ground the casing 22 of the inverter 2, so that even if the staff forgets to ground the casing 22 of the inverter 2, or the casing
  • the ground wire of 22 is faulty and other problems, if the user accidentally touches the shell 22 of the inverter 2, a voltage compensation circuit will not be formed through the human body, and the current connected to the voltage compensation circuit of the grid 4 will not pass through the human body. No danger to personal safety.
  • the inverter 2 cannot be grounded, it will not affect the voltage compensation effect of the voltage compensation device 3 on the bias voltage, thereby ensuring the quality of eliminating the PID effect.
  • the power output terminal of the voltage compensation device 3 can be grounded by coupling with the N line of the power grid 4, so that no additional wiring is required to achieve grounding. In this way, not only the workload and cost of wiring can be reduced, but also additional grounding wires can be avoided. security risks.
  • the voltage compensation device 3 is coupled to the power output terminal of the inverter 2 through the power input terminal or coupled to the grid 4 located outside the inverter 2 to obtain power.
  • the power input terminal of the voltage compensation device 3 is coupled to the power grid 4 located in the inverter. Take the power grid 4 outside the device 2 as an example.
  • the inverter 2 is a three-phase inverter, and the power input terminal of the voltage compensation device 3 can be coupled to any one of the ABC three-phase in the grid 4
  • the N line in the phase and grid realizes the power extraction, as follows:
  • FIG. 4 it is an example in which the voltage compensation device 3 draws power from the power grid 4 through one phase. It can be seen that one of the power input terminals of the voltage compensation device 3 is coupled to the power grid 4 In the C phase of the ABC phase, the other power input terminal of the power input terminal of the voltage compensation device 3 is coupled to the N line of the power grid 4, so as to obtain power between CN. In addition, one of the power input terminals of the voltage compensation device 3 can also be coupled to the A phase or the B phase, and the other power input terminal can be coupled to the N line to obtain power from AN or BN. In an implementation manner, FIG.
  • FIG. 5 is a schematic structural diagram of obtaining electric energy by coupling and connecting two phases in a power grid according to an embodiment of the present invention, and FIG. 5 only shows the connection between the power input terminal of the voltage compensation device 3 and the power grid 4 .
  • the rest of the structure in the photovoltaic power generation system can be seen in Figure 4, which is not described in this figure.
  • one of the power input terminals of the voltage compensation device 3 is coupled to the B phase in the power grid 4
  • the other power input terminal of the voltage compensation device 3 is coupled to the power grid 4 .
  • Phase C in this way, the voltage compensation device 3 can take power from between BC.
  • the power input terminals of the power input terminals of the voltage compensating device 3 can also be coupled and connected to any two phases of the ABC phase respectively, so as to realize power extraction from between AB and AC.
  • the voltage compensating device 3 can also couple and connect the N line of the power grid 4 on the basis of coupling and connecting any two phases of the ABC phase, so as to obtain electricity from ABN, ACN, and BCN, wherein the voltage compensating device 3 can also Choose not to connect the N line according to the actual situation.
  • FIG. 6 is a schematic structural diagram of obtaining electric energy by coupling and connecting three phases in a power grid according to an embodiment of the present invention, and FIG. 6 only shows the connection between the power input terminal of the voltage compensation device 3 and the power grid 4
  • the rest of the structure in the photovoltaic power generation system can be seen in Figure 4, which is not described in this figure.
  • the three power input terminals of the power input terminals of the voltage compensation device 3 are respectively coupled and connected to the three phases A, B and C in the power grid 4 , so that the voltage compensation device 3 can take power from between ABC.
  • the voltage compensating device 3 can also couple and connect the N line of the power grid 4 on the basis of coupling and connecting the ABC phases, so as to obtain electricity from between ABCN.
  • the power grid is an LN-phase power grid, as shown in Figure 7, the rest of the structure of the photovoltaic power generation system can be seen in Figure 4, which is not described in this figure.
  • the power input end of the voltage compensation device 3 needs to be connected to the L-phase and N lines of the power grid. .
  • connection mode between the power input terminal of the voltage compensation device 3 and the power grid 4 can be selected according to actual needs.
  • the connection mode of the voltage compensation device 3 can be more flexible.
  • the photovoltaic cell panel string 1 may adopt corresponding types according to actual needs, such as a P-type photovoltaic cell panel string, and an N-type photovoltaic cell panel string.
  • the types of bias voltages existing between them and PE are also different, and therefore, the types of compensation voltages used to compensate the generated bias voltages are also different.
  • PV panel string 1 is a P-type PV panel string
  • For solar panel strings there is usually a negative bias voltage between the power output terminal of PV panel string 1 and PE; however, for a few N-type PV panel strings, there are also PV panel strings.
  • a bias voltage that is a forward voltage exists between the power output terminal of String 1 and PE.
  • the type corresponding to the photovoltaic panel string 1 is P-type or most of the N-type photovoltaic panel strings, it means that the power output terminal of the photovoltaic panel string 1 generates a negative voltage to PE.
  • the required compensation voltage at this time is the forward voltage.
  • the positive pole of the power output terminal of the voltage compensation device 3 is coupled to the power output terminal of the photovoltaic panel string 1, and/or the power input terminal of the inverter 2, and/or Or the power input terminal of the inverter unit 21 in the inverter 2 , and/or the loop between the power input terminal of the inverter 2 and the power input terminal of the inverter unit 21 .
  • the positive pole of the power output terminal of the voltage compensation device 3 is coupled to the negative pole PV- of the power output terminal of the photovoltaic panel string 1 , and then the negative pole of the power output terminal of the voltage compensation device 3 is coupled to the N of the grid 4 .
  • the path between the positive electrode of the power output terminal of the voltage compensation device 3 and the negative electrode PV- of the power output terminal of the photovoltaic panel string 1, the voltage divider circuit 11, PE, and the voltage compensation device 3 The path between the negative pole of the power output terminal and the N line, and the path between the N line and PE form a voltage compensation loop, and then the power can be applied to the PV- and PE, a forward voltage is formed between PV- and PE of the power output terminal of the photovoltaic panel string 1, so that the forward voltage is used to control the PV- and PE of the power output terminal of the photovoltaic panel string 1.
  • the bias voltage between them acts as a compensation.
  • the positive electrode of the power output terminal of the voltage compensation device 3 when the positive electrode of the power output terminal of the voltage compensation device 3 is coupled to the power output terminal of the photovoltaic panel string 1, it can be coupled to the positive electrode PV+, the negative electrode PV-, or both of the power output terminal of the photovoltaic panel string 1.
  • the electric energy input terminal of the inverter 2 has a loop corresponding to the positive pole, a loop corresponding to the negative pole, or a loop corresponding to the positive pole and the negative pole at the same time.
  • FIG. 8 is a schematic structural diagram of a photovoltaic power generation system provided by an embodiment of the present invention. As shown in FIG. 8 , in order to obtain the compensation voltage of the negative voltage, the negative electrode of the electric energy output terminal of the voltage compensation device 3 needs to be coupled and connected to the photovoltaic panel group.
  • the power output terminal of string 1, and/or the power input terminal of inverter 2, and/or the power input terminal of inverter unit 21 in inverter 2, and/or the power input terminal of inverter 2 and the inverter The loop between the power inputs of the unit 21.
  • the negative pole PV- of the power output terminal of the photovoltaic panel string 1 is coupled and connected as an example, and then the positive pole of the power output terminal of the voltage compensation device 3 is coupled and connected to the N line of the power grid 4 .
  • the path between the negative electrode of the power output terminal of the voltage compensation device 3 and the negative electrode PV- of the power output terminal of the photovoltaic panel string 1, the voltage divider circuit 11, PE, and the power output terminal of the voltage compensation device 3 The path between the positive electrode and the N line and the path between the N line and the PE form a voltage compensation loop, and then the obtained electric energy can be applied to the PV- and PE of the electric energy output terminal of the photovoltaic panel string 1 through the voltage compensation loop.
  • a negative voltage is formed between PV- and PE of the power output terminal of the photovoltaic panel string 1, so that the negative voltage is used to apply the voltage between PV- and PE of the power output terminal of the photovoltaic panel string 1.
  • the bias voltage plays the role of compensation.
  • the negative electrode of the power output end of the voltage compensation device 3 may also be coupled and connected to the coupling connection position provided in the above implementation manner, which will not be repeated here.
  • FIG. 9 is a schematic structural diagram of a photovoltaic power generation system provided by an embodiment of the present invention.
  • the main difference between Embodiment 2 and Embodiment 1 is that, as shown in FIG. 9 , in the inverter device 7 , the voltage compensation device 3 and the inverter Components such as the unit 21 are packaged together inside the casing 22 of the inverter 2, so that the inverter 2 is equivalent to an inverter with a voltage compensation function.
  • the wiring between the inverter 2 and the coupling loop is the internal wiring of the inverter 2
  • the wiring between the voltage compensation device 3 and the power output terminal of the photovoltaic panel string 1 is the external wiring of the inverter 2.
  • the inverter 2 with a suitable internal wiring structure can save the wiring operation inside the inverter 2 when the inverter 2 is used, and only need to perform the external wiring operation of the inverter 2 .
  • the photovoltaic power generation system includes a photovoltaic panel string 1 and an inverter device 7 , the inverter device 7 includes an inverter 2 and a voltage compensation device 3 ; the power output terminal of the photovoltaic panel string 1
  • the power input terminal of the inverter 2 is coupled and connected to the power grid 4; the power output terminal of the inverter 2 is coupled to the power grid 4;
  • Power grid 4 obtains electrical energy; one pole of the electrical energy output terminal of the voltage compensation device 3 can be coupled to the electrical energy output terminal of the photovoltaic panel string 1, and/or the electrical energy input terminal of the inverter 2, and/or Or the power input terminal of the inverter unit 21 in the inverter 2 , and/or the loop between the power input terminal of the inverter 2 and the power input terminal of the inverter unit 21 .
  • one pole of the power output terminal of the voltage compensation device 3 may only be coupled and connected to the power output terminal of the photovoltaic panel string 1 , the power input terminal of the inverter 2 , and the inverter in the inverter 2 .
  • one pole of the power output terminal of the voltage compensation device 3 may also be coupled to the power output terminal of the photovoltaic panel string 1 , the power input terminal of the inverter 2 , and the power output terminal of the inverter 2 at the same time. Any two or more positions in the loop between the power input terminal of the inverter unit 21 , the power input terminal of the inverter 2 and the power input terminal of the inverter unit 21 .
  • one pole of the power output terminal of the voltage compensation device 3 is coupled to the power input terminal of the inverter unit 21 in the inverter 2 , for example, coupled to the DC bus, and the other pole of the power output terminal of the voltage compensation device 3 is coupled.
  • the N line connected to the grid 4 by pole coupling as an example, so that the electric energy obtained from the grid 4 can be applied between the electric energy output terminal of the photovoltaic panel string and the ground.
  • FIG. 10 is a schematic structural diagram of an inverter provided by an embodiment of the present invention.
  • the inverter provided in FIG. 10 sets all the wiring of the voltage compensation device to the internal wiring of the inverter, as shown in FIG. 10, the inverter 2 includes: an inverter unit 21, a housing 22, a grid-connected switch unit 23, an electric energy input terminal 24, an electric energy output terminal 25 and a voltage compensation device 3, and may also include a DC/DC direct current transformation unit 26 .
  • the power input terminal 24 and the power output terminal 25 are arranged on the casing 22, the power input terminal 24 is used for coupling and connecting the power output terminal of the photovoltaic panel string 1, the power output terminal 25 is used for coupling and connecting the power grid 4, and the inverter unit
  • the power input terminal 21 is coupled to the power input terminal 24.
  • the power input terminal 24 is coupled to the power input terminal of the DC/DC direct current transformer unit 26.
  • the DC/DC direct current transformer unit The power output end of 26 is coupled to the power input end of the inverter unit 21, wherein the DC/DC direct current transformer unit 26 is used for receiving the direct current transmitted by the photovoltaic panel string 1, and inverting the direct current into a voltage that meets the standard. voltage, and then transmit the inverted direct current to the inverter unit 21 , and the power output terminal of the inverter unit 21 is coupled to the power output terminal 25 through the grid-connected switch unit 23 .
  • the inverter 2 is coupled and connected to the power output terminal of the photovoltaic cell panel string 1 through the power input terminal 24 to receive the power input by the photovoltaic cell panel string 1 .
  • the inverter 2 is coupled and connected to the grid 4 through the power output terminal 25 to input the inverted current into the grid 4 .
  • the inverter also includes a grid-connected switch unit 23.
  • the grid-connected switch unit 23 is arranged on the coupling loop between the power output terminal of the inverter unit 21 and the power output terminal 25, and is used to control the connection between the inverter unit 21 and the power grid 4. connection and disconnection.
  • the inverter 2 may further include other components, such as capacitors, inductors, etc., which are not shown one by one in this embodiment.
  • the power connection method of the voltage compensation device 3 is as follows: as shown in FIG.
  • the difference from Embodiment 1 is that the power-taking and wiring method of the voltage compensation device 3 provided in Embodiment 2 is the internal wiring of the inverter 2. Therefore, the user can omit the voltage compensation device 3 when installing the inverter. For the wiring operation with the grid 4, it is only necessary to select the corresponding inverter product according to the actual wiring needs.
  • One pole of the power output terminal of the voltage compensation device 3 may be coupled to the power output terminal coupled to the N line of the power grid 4, and/or coupled to the power output terminal coupled to the N line of the power grid 4 in the inverter 2
  • FIG. 10 takes the coupling loop corresponding to the power output terminal in the inverter 2 where one pole of the power output terminal of the voltage compensating device 3 is coupled to the N line of the power grid 4 is coupled.
  • the other pole of the power output terminal of the voltage compensation device 3 may be coupled to the power input terminal of the inverter 2 , and/or the power input terminal of the inverter unit 21 in the inverter 2 , and/or the power input terminal of the inverter 2 .
  • a loop between the power input terminal and the power input terminal of the inverter unit 21 FIG. 11 shows an example of coupling and connecting the power input terminal 24 with the other pole of the power output terminal of the voltage compensation device 3
  • FIG. 9 shows the other pole of the power output terminal of the voltage compensation device 3 coupling and connecting the inverter.
  • BUS DC bus
  • the coupling connection line between the positive electrode of the power output end of the DC/DC transformer unit 26 and the inverter unit 21 is BUS+
  • FIG. 12 shows an example of the loop between the power input terminal of the inverter 2 and the power input terminal of the inverter unit 21 coupled with the other pole of the power output terminal of the voltage compensation device 3 , which is not specifically disclosed in FIG. 12 .
  • the internal wiring structure of the DC/DC transformation unit 26 only represents the loop between the power input terminal of the inverter 2 and the power input terminal of the inverter unit 21 through the DC/DC DC transformation unit 26 .
  • the specific selection method of which pole is used to connect the electric energy output terminal of the voltage compensation device 3 to which pole of the above-mentioned coupling wiring object may refer to the description in Embodiment 1, and will not be repeated here.
  • the inverter 2 may also select a three-phase inverter as shown in FIG. 10 according to the type of the power grid, or a single-phase inverter as shown in FIG. 13 .
  • a three-phase inverter selects a three-phase inverter
  • a single-phase inverter selects a single-phase inverter.
  • the voltage compensation device 3 includes a power conversion module, and the power conversion module is respectively coupled to the power input terminal of the voltage compensation device 3 and the power output terminal of the voltage compensation device 3 for obtaining the power from the power grid 4
  • the electric energy from the power grid can be converted into a current type suitable for the photovoltaic panel string 1 side.
  • the power conversion module is an AC/DC conversion unit. In this way, the alternating current obtained from the grid 4 can be converted into photovoltaic cells. DC power applicable to the circuit on the 1 side of the board string.
  • the power conversion module is an isolated AC/DC conversion unit, which can effectively isolate the grid 4 and the photovoltaic panel string 1, thereby reducing the interference and influence of the grid 4 on the photovoltaic panel string 1, thereby improving the photovoltaic panel
  • the stability and safety of string 1 can effectively realize the conversion of current types.
  • the coupling connection mentioned in Embodiment 1 and Embodiment 2 may be any one of direct coupling connection, coupling connection through switching device, coupling connection through current limiting component, and coupling connection through switching device and current limiting component.
  • the direct coupling connection means that the two devices are directly connected by a wire
  • the coupling connection through a switching device means that the two devices are connected by a wire, and the connection and disconnection are controlled by the switching device
  • through the current limiting component Coupling connection that is, the two devices are connected by wires, and the current value flowing between the two devices is limited by the current limiting component, thereby protecting the safety of the two circuits and devices
  • coupling through the switching device and the current limiting component Connection that is, the two devices are connected by a wire, and the connection and disconnection are controlled by the switching device, and the current value flowing between the two devices is limited by the current limiting component.
  • Users can choose a suitable coupling connection method according to actual use requirements, which is not limited here.
  • the switching device may be one or a combination of semiconductor switches, relays, contactors, circuit breakers, and mechanical switches.
  • the current limiting component can be a resistor, an inductor or a current limiting circuit.
  • the power conversion module may further include components for assisting the AC/DC conversion unit to realize the power conversion function, such as switches, resistors, etc., and the AC/DC conversion unit and these components may be used
  • a variety of wiring methods, and finally coupled with the power input terminal and the power output terminal of the voltage compensation device 3 (for the sake of simplicity, the description of the coupling connection between the internal components of the power conversion module and the power output terminal 32 will be omitted, and it will be simplified as power
  • the corresponding relationship between the internal components of the conversion module and the power grid 4 as follows:
  • FIG. 14 is a schematic diagram of the internal structure of a power conversion module provided by an embodiment of the present invention.
  • the power conversion module includes an AC/DC conversion unit, a first switch, a second The switch, the third switch and the fourth switch (the first switch and the fourth switch in FIG. 14 correspond to K1-K4 respectively, wherein the descriptions of the first, second, third and fourth are only for convenience of description and do not limit the specific function, and will not limit the scope of protection of the scheme).
  • the power grid 4 corresponding to FIG.
  • the power input terminal of the AC/DC conversion unit is coupled to the power output terminal of the power output terminal of the voltage compensation device 3 which is coupled to the power grid ABC through the first switch, and the AC/DC power output terminal is coupled to the power grid ABC.
  • the power input terminal of the DC conversion unit is coupled to the power output terminal of the power output terminal of the voltage compensation device 3 coupled to the N line in the power grid 4 through the second switch. As shown in FIG.
  • the power input terminal of the AC/DC conversion unit is The terminals are respectively coupled to the power output terminals of the voltage compensation device 3 coupled to the B-phase and N lines in the power grid 4 (if the power grid is an LN-phase power grid, the power input terminal of the AC/DC conversion unit is connected to the power grid 4 through the first switch.
  • the L-phase is coupled and connected, and is coupled and connected to the N line in the power grid 4 through the second switch), so that electricity can be obtained from the power grid 4 .
  • the coupling connection between the AC/DC conversion unit and other devices is through the coupling connection of the switching device, so that the connection and disconnection of different connection lines can be controlled through K1-K4.
  • the number of the first switches may be one or more, and the specific number of the first switches is related to the type of the grid 4 to which the power conversion module 31 is coupled and connected, as well as the type of wiring and power taking.
  • the grid 4 is LN phase grid
  • the first switch is one, and it is arranged on the connection line between the input terminal of the AC/DC conversion unit and the L phase of the grid 4, at this time, the second switch is in the connected state;
  • the grid 4 is an ABC-type grid , and the type of wiring used to take power is to take power from between the BC phases
  • the first switches are two, and they are respectively arranged on the connection between the power input end of the AC/DC conversion unit and the B phase and C phase of the power grid 4 At this time, the second switch is in the off state; or the wiring type is to take power from between the BN phases, as shown in Figure 14, the first switch is one, and it is set in the AC/DC conversion unit On the connection between the power input end of 1 and the B phase
  • connection and disconnection of the connection where it is located can effectively control the flow of current and prevent the damage to the photovoltaic power generation system caused by problems such as abnormal current.
  • the AC/DC conversion unit can also establish connections with the power output terminals of the voltage compensation devices 3 corresponding to the power grid 4, and realize the connection through the first switch provided on each connection. The connection and disconnection of the line to control the phase that takes electricity.
  • One pole of the power output end of the AC/DC conversion unit is coupled to the power input terminal of the voltage compensation device 3 through the third switch, so that the AC/DC conversion unit and the power input terminal of the voltage compensation device 3 can be controlled by controlling the third switch
  • the connection and disconnection between the AC/DC conversion unit or the grid 4 can be disconnected in time, so as to protect the photovoltaic panel string 1 side. component security.
  • the other pole of the power output end of the AC/DC conversion unit is coupled and connected to the N line of the power grid 4 through the fourth switch, so as to realize grounding.
  • the coupling connection point of the N line where the power output end of the AC/DC conversion unit is connected to the power grid 4 is on the connection line between the AC/DC conversion unit and the second switch.
  • one switch that is, the second switch, can be used to control the connection and disconnection of the two lines that form a voltage compensation circuit for taking electricity and grounding at the same time. Control the circuit in time.
  • FIG. 15 is a schematic diagram of the internal structure of a power conversion module provided by an embodiment of the present invention.
  • the difference between FIG. 15 and FIG. 14 is that the power output end of the DC/AC conversion unit is connected to the N of the power grid 4
  • the coupling connection point of the line is on the coupling connection line of the second switch and the N line of the grid 4 .
  • the second switch only controls the connection and disconnection of power taking between the AC/DC conversion unit and the power grid 4.
  • the connection and disconnection of the two lines that form a voltage compensation loop for power taking and grounding can be effectively realized.
  • the decoupling of the open control makes the control of the second switch more targeted.
  • the first switch, the second switch, the third switch and the fourth switch in this embodiment can also be based on actual needs, such as installation method, control method, space occupation, cost, safety etc., using one or a combination of semiconductor switches, relays, contactors, circuit breakers, and mechanical switches. For example, if you want to increase the automation of control, you can use relays.
  • FIG. 16 is a schematic diagram of the internal structure of a power conversion module provided by the present invention. As shown in Figure 16, in order to reduce the damage to each component, a coupling connection method through a current limiting component can be used, that is, the AC/DC conversion unit and the Current limiting components are arranged between the N lines of the power grid 4 to reduce the current flowing through each component and protect each component. Wherein, as shown in FIG.
  • the current limiting component can be arranged between the fourth switch and the N line of the power grid.
  • the current limiting component can also be arranged between the fourth switch and the AC/DC conversion unit.
  • any one of a resistor, an inductor, and a current limiting circuit can be selected as the current limiting component according to actual needs, and a resistor is selected as the current limiting component in FIG. 16 .
  • FIG. 17 is a photovoltaic power generation system with a controller provided by an embodiment of the present invention.
  • a schematic diagram of the structure of the power generation system is shown in Figure 17.
  • Figure 17 takes the photovoltaic power generation system in which the inverter 2 and the voltage compensation device 3 are two independent devices as an example.
  • the controller 5 is connected to the inverter 2 and the voltage compensation device 3 respectively. coupled communication. If the photovoltaic panel string 1 generates electric energy, it means that the photovoltaic panel string 1 is in the working state.
  • the controller 5 controls the inverter 2 to be turned on. , and turn off the voltage compensation device 3; if the photovoltaic panel string 1 does not generate electricity, it means that the photovoltaic panel string 1 is not in a working state. At this time, the voltage compensation operation can be performed on the photovoltaic panel string 1. Therefore, The controller 5 controls to turn off the inverter 2 and turn on the voltage compensation device 3 . In this way, the photovoltaic power generation system can be automatically controlled by the controller 5, so as to reduce manpower and improve the work efficiency and quality of the photovoltaic power generation system.
  • a control unit 6 is provided in the inverter 2.
  • the /DC DC transformation unit 26 , the grid-connected switch unit 23 , and the voltage compensation device 3 are coupled.
  • the control unit 6 can realize the automatic control of the inverter unit 21 , the DC/DC transformation unit 26 , the grid-connected switch unit 23 and the voltage compensation device 3 , thereby improving the control accuracy of the inverter 2 .
  • the control unit 6 is included in the inverter 2 , the control unit 6 is also coupled to communicate with the controller 5 and is controlled by the controller 5 .

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

本发明实施例提供了一种电压补偿装置、逆变装置和光伏发电系统，其中，所述系统包括：光伏电池板组串和逆变装置，所述逆变装置包括逆变器和电压补偿装置，其中，电压补偿装置的电能输出端子的一极耦合连接电网的N线。这样，电压补偿装置的电能输出端可以通过直接耦合连接电网的N线，形成电能补偿回路，而无需依托于逆变器的接地线形成电能补偿回路，从而可以杜绝人员误触逆变器外壳时的触电风险。

Description

一种电压补偿装置、逆变装置及光伏发电系统
本申请要求于2020年7月24日申请的申请号为202010721883.0，发明名称为“一种电压补偿装置、逆变装置及光伏发电系统”的优先权。
技术领域
本申请涉及光伏发电领域，尤其涉及一种电压补偿装置、逆变装置及光伏发电系统。
背景技术
光伏电池板组串是光伏发电系统(PV Generator System)的主要部件，光伏电池板组串在潮湿的环境中容易产生电势诱导衰减(Potential Induced Degradation，PID)效应，光伏电池板组串的PID效应也就是光伏电池板组串对地存在的偏置电压，并在该偏置电压的作用下出现功率衰减的现象。光伏电池板组串的PID效应会使光伏电池板组串的功率严重衰减，从而影响整个发电站的功率输出，因此，降低光伏电池板组串的PID效应对光伏电池板组串的影响是非常重要的。
基于光伏电池板组串PID效应产生原理的可逆原理，可以利用补偿回路对光伏电池板组串的PID效应进行修复，在光伏发电系统的逆变器的内部构建电压补偿装置，当光伏电池板组串无光照时，通过电压补偿装置从电网取电，并向光伏电池板组串与保护导体(Protecting Earthing，PE)之间输出补偿电压，从而对光伏电池板组串的PID效应进行修复，以提升光伏发电系统的发电量。其中，电压补偿装置的电能输入端与电网耦合连接，电压补偿装置的电能输出端的一极与光伏电池板组串耦合连接，功率变换模块的电能输出端的另一极与逆变器的外部机壳耦合连接，再通过逆变器的外部机壳实现与PE耦合连接，此时，由PE、光伏电池板组串与PE之间的通路、电压补偿装置与光伏电池板组串之间的通路、电压补偿装置与逆变器的外部机壳之间的通路、逆变器的外部机壳与PE之间的通路形成一个补偿回路，以对由于光伏电池板组串与PE之间的偏置电压造成光伏电池板组串的电压衰减进行补偿，从而对光伏电池板组串的PID效应进行修复。
由于PE与逆变器的外部机壳是两个相互独立的部件，因此，需要在PE与逆变器的外部机壳之间设置接线以实现二者之间的电耦合连接。逆变器的外部机壳与PE之间的接线通常由人工完成，这就容易出现漏接或者接线质量较低(接触不良)等问题，一旦出现上述问题，上文所述的补偿回路将出现断路，就会丧失对光伏电池板的PID效应的修复效果。
发明内容
本申请提供了一种电压补偿装置、逆变装置及光伏发电系统，以解决现有光伏电池板的PID效应修复质量差的问题。
第一方面，本发明实施例提供了一种电压补偿装置，包括功率变换模块，所述功 率变换模块分别耦合连接所述电压补偿装置的电能输入端子和所述电压补偿装置的电能输出端子，所述电压补偿装置的电能输入端子耦合连接电网，用于从所述电网获取电能；所述电压补偿装置的电能输出端子的一极耦合连接光伏电池板组串的电能输出端子，和/或逆变器的电能输入端子，和/或所述逆变器中逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的另一极耦合连接所述电网的N线，用于将从所述电网获取的电能施加在所述光伏电池板组串的电能输出端子与大地之间。
这样，可以在光伏电池板组串不进行发电时，由电压补偿装置从电网取电，然后对光伏电池板组串对地消耗的偏置电压进行补偿，从而修复光伏电池板组串出现的功率衰减的现象。同时，由于电压补偿装置的电能输出端子直接耦合连接电网的N极，形成电能补偿回路，无需依托于逆变器的接地线形成电能补偿回路，因此，即使出现逆变器的接地线漏接或者接线质量较低时，仍然可以对光伏电池板组串进行电压补偿，而且，可以规避人员触电风险。
在一种实现方式中，如果所述电压补偿装置设置于所述逆变器的内部，则所述电压补偿装置的电能输入端子耦合连接所述逆变器内并网开关单元与所述逆变器的电能输出端子之间的回路。
在一种实现方式中，如果所述电压补偿装置设置于所述逆变器的外部，则所述电压补偿装置的电能输入端子耦合连接所述逆变器的电能输出端子或者耦合连接位于所述逆变器外部的电网。
这样，电压补偿装置可以根据其设置的位置，选择合适的取电接线方式。
在一种实现方式中，所述电压补偿装置的电能输入端子分别耦合连接所述电网的ABC相中至少一相和所述电网的N线；或者，所述电压补偿装置的电能输入端子连接所述电网的ABC相中至少两相；或者，所述电压补偿装置的电能输入端子耦合连接所述电网的L相与所述电网的N线。
这样，电压补偿装置可以根据电网的类型和实际需要，选择耦合连接电网的L相，或者，ABC相中的一相、两相、三相来获取电压，可以为电压补偿装置的取电接线方式提供更多的选择。
在一种实现方式中，如果所述光伏电池板组串对应的补偿电压为正向电压，则所述电压补偿装置的电能输出端子的正极耦合连接所述光伏电池板组串的电能输出端子，和/或所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的负极耦合连接所述电网的N线；或者，如果所述光伏电池板组串对应的补偿电压为负向电压，则所述电压补偿装置的电能输出端子的负极耦合连接所述光伏电池板组串的电能输出端子，和/或所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的正极耦合连接所述电网的N线。
这样，可以根据光伏电池板组串实际需要补偿的电压类型，选择正确的接线方式，从而提高电压补偿的效果。
在一种实现方式中，所述功率变换模块为隔离AC/DC变换单元。
在一种实现方式中，耦合连接为直接耦合连接、通过开关器件耦合连接、通过限流组件耦合连接、通过开关器件和限流组件耦合连接中的至少一种连接方式。
这样，用户可以根据需要灵活选择合适的耦合连接方式。
在一种实现方式中，所述开关器件为半导体开关、继电器、接触器、断路器、机械开关中的一种或者几种的组合。
这样，可以根据实际需求，例如成本、安全规则等选择合适的开关器件。
在一种实现方式中，所述限流组件为电阻、电感或者限流电路。
第二方面，本发明实施例提供了一种逆变装置，所述逆变装置包括：逆变器和如第一方面中所述的电压补偿装置；所述逆变器包括外壳、电能输入端子、电能输出端子、逆变单元和并网开关单元；所述电能输入端子和所述电能输出端子设置于所述外壳上，所述电能输入端子用于耦合连接光伏电池板组串的电能输出端子，所述电能输出端子用于耦合连接电网；所述逆变单元、所述并网开关单元和所述电压补偿装置均设置于所述逆变器的内部；所述逆变单元的电能输入端耦合连接所述电能输入端子；所述逆变单元的电能输出端通过所述并网开关单元耦合连接所述电能输出端子；所述电压补偿装置的电能输入端子耦合连接所述并网开关单元与所述电能输出端子之间的回路；所述电压补偿装置的电能输出端子的一极耦合连接与所述电网的N线耦合连接的电能输出端子,和/或耦合连接与所述电网的N线耦合连接的电能输出端子在所述逆变器内对应的耦合回路，所述电压补偿装置的电能输出端子的另一极耦合连接所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述电能输入端子与所述逆变单元的电能输入端之间的回路。
这样，逆变器可以用于光伏发电系统中，该逆变器可以同时实现将光伏电池板组串发送的直流电转换为交流电，以及补偿光伏电池板组串的电压的效果，其中，电压补偿装置的电能输出端子的一极耦合连接电网的N线，以实现接地，而无需依赖逆变器本身的接地线，来形成电压补偿回路。因此，即使出现逆变器的接地线漏接或者接线质量较低时，仍然可以对光伏电池板组串进行电压补偿，而且，可以规避人员触电风险。
在一种实现方式中，如果所述光伏电池板组串对应的补偿电压为正向电压，则所述电压补偿装置的电能输出端子的正极耦合连接所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的负极耦合连接与所述电网的N线耦合连接的电能输出端子,和/或耦合连接与所述电网的N线耦合连接的电能输出端子在所述逆变器内对应的耦合回路；或者，如果所述光伏电池板组串对应的补偿电压为负向电压，则所述电压补偿装置的电能输出端子的负极耦合连接所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的正极耦合连接与所述电网的N线耦合连接的电能输出端子,和/或耦合连接与所述电网的N线耦合连接的电能输出端子在所述逆变器内对应的耦合回路。
这样，电压补偿装置可以根据其设置的位置，选择合适的取电接线方式。
在一种实现方式中，所述电压补偿装置的电能输入端子分别耦合连接所述电网的ABC相中至少一相和所述电网的N线；或者，所述电压补偿装置的电能输入端子连接所述电网的ABC相中至少两相；或者，所述电压补偿装置的电能输入端子耦合连接所述电网的L相与所述电网的N线。
这样，电压补偿装置可以根据电网的类型和实际需要，选择耦合连接电网的L相，或者，ABC相中的一相、两相、三相来获取电压，可以为电压补偿装置的取电接线方式提供更多的选择。
在一种实现方式中，所述逆变器还包括DC/DC直流变压单元；所述DC/DC直流变压单元的输入端子耦合连接所述电能输入端子；所述DC/DC直流变压单元的输出端子耦合连接所述逆变单元的输入端子。
这样，DC/DC直流变压单元可以将逆变后的直流电转换为电压符合光伏电池板组串侧使用的电压。
在一种实现方式中，所述电压补偿装置包括功率变换模块；所述功率变换模块分别与所述电压补偿装置的电能输入端子和所述电压补偿装置的电能输出端子耦合；其中，所述功率变换模块隔离AC/DC变换单元。
这样，电压补偿装置可以通过电能输入端子从电网接入电压，并通过功率变换模块将接入的电压传递至光伏电池板组串，最后由电能输出端子接入电网的N线，从而实现一个电压补偿回路，为光伏电池板组串补偿电压，，并且实现将交流电压转换为直流电压。
在一种实现方式中，耦合连接为直接耦合连接、通过开关器件耦合连接、通过限流组件耦合连接、通过开关器件和限流组件耦合连接中的至少一种连接方式。
这样，用户可以根据需要灵活选择合适的耦合连接方式。
在一种实现方式中，所述开关器件为半导体开关、继电器、接触器、断路器、机械开关中的一种或者几种的组合。
这样，可以根据实际需求，例如成本、安全规则等选择合适的开关器件。
在一种实现方式中，所述限流组件为电阻、电感或者限流电路。
在一种实现方式中，所述逆变器还包括控制单元；所述控制单元分别与所述逆变单元、所述DC/DC直流变换单元、所述并网开关单元和所述电压补偿装置耦合连接。
这样，可以通过控制单元实现对逆变单元、DC/DC直流变换单元、并网开关单元以及电压补偿装置的自动控制，从而提高对逆变器的控制精确度。
第三方面，本发明实施例提供了一种光伏发电系统，所述光伏发电系统包括：光伏电池板组串和逆变装置，所述逆变装置包括逆变器和如第一方面中所述的电压补偿装置；所述光伏电池板组串的电能输出端子耦合连接所述逆变器的电能输入端子；所述逆变器的电能输出端子耦合连接电网；所述电压补偿装置的电能输入端子耦合连接所述电网，用于从所述电网获取电能；所述电压补偿装置的电能输出端子的一极耦合连接所述光伏电池板组串的电能输出端子，和/或所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的另一极耦合连接所述电网的N线，用于将从所述电网获取的电能施加在所述光伏电池板组串的电能输 出端子与大地之间。
这样，可以在光伏电池板组串不进行发电时，由电压补偿装置从电网取电，然后对光伏电池板组串对地消耗的偏置电压进行补偿，从而修复光伏电池板组串出现的功率衰减的现象。同时，由于电压补偿装置的电能输出端子直接耦合连接电网的N极，形成电能补偿回路，无需依托于逆变器的接地线形成电能补偿回路，因此，即使出现逆变器的接地线漏接或者接线质量较低时，仍然可以对光伏电池板组串进行电压补偿，而且，可以规避人员触电风险。
在一种实现方式中，如果所述电压补偿装置设置于所述逆变器的内部，则所述电压补偿装置的电能输入端子耦合连接所述逆变器内并网开关单元与所述逆变器的电能输出端子之间的回路；如果所述电压补偿装置设置于所述逆变器的外部，则所述电压补偿装置的电能输入端子耦合连接所述逆变器的电能输出端子或者耦合连接位于所述逆变器外部的电网。
这样，电压补偿装置可以根据其设置的位置，选择合适的取电接线方式。
在一种实现方式中，所述电压补偿装置的电能输入端子分别耦合连接所述电网的ABC相中至少一相和所述电网的N线；或者，所述电压补偿装置的电能输入端子耦合连接所述电网的ABC相中至少两相；或者，所述电压补偿装置的电能输入端子耦合连接所述电网的L相与所述电网的N线。
这样，电压补偿装置可以根据电网的类型和实际需要，选择耦合连接电网的L相，或者，ABC相中的一相、两相、三相来获取电压，可以为电压补偿装置的取电接线方式提供更多的选择。
在一种实现方式中，如果所述光伏电池板组串对应的补偿电压为正向电压，则所述电压补偿装置的电能输出端子的正极耦合连接所述光伏电池板组串的电能输出端子，和/或所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的负极耦合连接所述电网的N线；或者，如果所述光伏电池板组串对应的补偿电压为负向电压，则所述电压补偿装置的电能输出端子的负极耦合连接所述光伏电池板组串的电能输出端子，和/或所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的正极耦合连接所述电网的N线。
这样，可以根据光伏电池板组串实际需要补偿的电压类型，选择正确的接线方式，从而提高电压补偿的效果。
在一种实现方式中，所述电压补偿装置包括功率变换模块；所述功率变换模块分别与所述电压补偿装置的电能输入端子和所述电压补偿装置的电能输出端子耦合；其中，所述功率变换模块为隔离AC/DC变换单元。
这样，电压补偿装置可以通过电能输入端子从电网接入电压，并通过功率变换模块将接入的电压传递至光伏电池板组串，最后由电能输出端子接入电网的N线，从而实现一个电压补偿回路，为光伏电池板组串补偿电压，并且实现将交流电压转换为直流电压。
在一种实现方式中，耦合连接为直接耦合连接、通过开关器件耦合连接、通过限流组件耦合连接、或者通过开关器件和限流组件耦合连接。
这样，用户可以根据需要灵活选择合适的耦合连接方式。
在一种实现方式中，所述开关器件为半导体开关、继电器、接触器、断路器、机械开关中的一种或者几种的组合。
这样，可以根据实际需求，例如成本、安全规则等选择合适的开关器件。
在一种实现方式中，所述限流组件为电阻、电感或者限流电路。
在一种实现方式中，所述系统还包括控制器；所述控制器分别与所述逆变器和所述电压补偿装置耦合通信，用于所述逆变器和所述电压补偿装置的开启和关闭。
这样，可以通过控制器实现对逆变器和电压补偿装置的自动控制，从而提高电压补偿过程的控制精确度。
附图说明
为了更清楚地说明本申请的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，显而易见地，对于本领域普通技术人员而言，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1为一种光伏发电系统的结构示意图；
图2为一种电压补偿回路的示意图；
图3为一种人体触点示意图；
图4为本发明实施例提供的一种光伏发电系统的结构示意图；
图5为本发明实施例提供的一种通过耦合连接ABC相电网中的两相获取电能的结构示意图；
图6为本发明实施例提供的一种通过耦合连接ABC相电网中的三相获取电能的结构示意图；
图7为本发明实施例提供的一种通过耦合连接LN相电网中获取电能的结构示意图；
图8为本发明实施例提供的一种光伏发电系统的结构示意图；
图9为本发明实施例提供的一种光伏发电系统的结构示意图；
图10为本发明实施例提供的一种逆变装置的结构示意图；
图11为本发明实施例提供的一种逆变装置的结构示意图；
图12为本发明实施例提供的一种逆变装置的结构示意图；
图13为本发明实施例提供的一种单相逆变器的内部结构示意图；
图14为本发明实施例提供的一种功率变换模块的内部结构示意图；
图15为本发明实施例提供的一种功率变换模块的内部结构示意图；
图16为本发明实施例提供的一种功率变换模块的内部结构示意图；
图17为本发明实施例提供的一种带有控制器的光伏发电系统的结构示意图；
图18为本发明实施例提供的一种带有控制单元的逆变器的结构示意图。
图示说明：
其中，1-光伏电池板组串，11-分压电路，2-逆变器，21-逆变单元，22-外壳，23-并网开关单元，24-电能输入端子，25-电能输出端子，26-DC/DC直流变压单元，3-电 压补偿装置，31-功率变换模块，32-电能输入端子，33-电能输出端子，4-电网，5-控制器，6-控制单元，7-逆变装置。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整的描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
图1为一种光伏发电系统的结构示意图，如图1所示，光伏发电系统包括光伏电池板组串1和逆变装置7，逆变装置7包括逆变器2和电压补偿装置3，其中，光伏电池板组串1的电能输出端子与逆变器2的电能输入端子耦合连接，可以使光伏电池板组串1将产生的直流电传输至逆变器2，同时，光伏电池板组串1的电能输出端子的负极pv-接地。逆变器2可以利用逆变单元21，例如直流/交流(Direct Current/Alternating Current，DC/AC)变换单元，将接收到的直流电转化为符合电网要求的交流电，逆变器2的电能输出端子与电网4耦合连接，这样，逆变器2就可以将转化后的交流电传输至电网4，再由电网4将交流电传输至各个用电单位，同时，逆变器2还可以通过外壳22接地，以保障使用安全。经过上述过程，也就可以完成光伏发电系统的发电过程。
但是，光伏电池板组串1中各光伏组件的串并联结构构成的光伏阵列令光伏电池板组串1的电能输出端子与大地之间产生寄生电容和阻抗，即产生PID效应，其中，如图1所示，光伏电池板组串1的电能输出端子的正极pv+对地之间存在寄生电容C+和寄生阻抗R+，光伏电池板组串1的电能输出端子的负极pv-对地之间存在寄生电容C-和寄生阻抗R-。这些寄生电容和阻抗对光伏电池板组串1起到分压的作用，这些寄生电容和寄生阻抗可以用图1中的分压电路11进行示意。正是由于分压电路的存在，会导致光伏电池板组串1对地产生偏置电压，从而令光伏电池板组串1在该偏置电压的作用下，出现功率衰减的现象，即出现PID效应，为了降低PID效应对光伏电池板组串1的影响，可以采用电压补偿装置3对光伏电池板组串1的电能输出端子与大地之间的偏置电压进行电压补偿，从而降低PID效应的影响。
具体地，如图1所示，电压补偿装置3设置于逆变器2内，电压补偿装置3的电能输入端子与电网4耦合连接，当光伏电池板组串1停止发电工作之后，电压补偿装置3开始从电网4取电。电压补偿装置3的电能输出端子的一极与光伏电池板组串1一侧耦合连接，图1以电压补偿装置3的电能输出端子的一极与逆变器2的电能输入端子和逆变单元21的输入端子之间的回路为例，同时，电压补偿装置3的电能输出端子的另一极通过外壳22接地，图2为一种电压补偿回路的示意图，如图2中较粗的虚线所示，由电压补偿装置3与分压电路11之间的通路、分压电路11、PE、电压补偿装置3与逆变器2的外壳22之间的通路、逆变器2的外壳22与PE之间的通路形成电压补偿回路，从而实现将补偿电压施加在光伏电池板组串1的电能输出端子与PE之间，对偏置电压进行补偿。由电压补偿回路的构成可知，如果电压补偿装置3想要对偏置电压实现电压补偿，必须保证逆变器2的外壳22的接地质量，如果出现接地线漏接，或者接地质量较差的情况，就会令电压补偿回路断开，从而令电压补偿装置3无 法对偏置电压进行电压补偿，也就无法解决PID效应对光伏电池板组串1的影响。同时，如图3所示，一旦有人在无保护的情况下接触逆变器2的外壳22，就会由人体实现外壳22接地，此时，电压补偿回路中PE与逆变器2的外壳22之间经过人体连通，电流经过人体，会对人造成巨大伤害。
由上述可知，通过逆变器2实现电压补偿模块3的接地，以形成电压补偿回路的方法，会存在电压补偿回路失效，或者造成人身安全危害的问题。为了解决上述问题，本发明提供了以下方法：
本发明实施例提供的一种光伏发电系统，所述系统包括：光伏电池板组串和逆变装置，逆变装置包括逆变器和电压补偿装置；所述光伏电池板组串的电能输出端子耦合连接所述逆变器的电能输入端子；所述逆变器的电能输出端子耦合连接电网；所述电压补偿装置的电能输入端子耦合连接所述电网，用于从所述电网获取电能；所述电压补偿装置的电能输出端子的一极耦合连接所述光伏电池板组串的电能输出端子，和/或所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的另一极耦合连接所述电网的N线，用于将从所述电网获取的电能施加在所述光伏电池板组串的电能输出端子与大地之间。
实施例1
图4为本发明实施例提供的一种光伏发电系统的结构示意图，如图4所示，在本实施例中，在逆变装置7中，逆变器2与电压补偿装置3为两个独立器件，电压补偿装置3设置于逆变器2的外部。电压补偿装置3的电能输出端子的一极通过耦合连接电网4的N线实现接地，电压补偿装置3的电能输出端子的另一极可以耦合连接光伏电池板组串1的电能输出端子，和/或所述逆变器2的电能输入端子，和/或所述逆变器2中的逆变单元21的电能输入端，和/或所述逆变器2的电能输入端子与所述逆变单元21的电能输入端之间的回路。在一种实现方式中，电压补偿装置3的电能输出端子的另一极可以只耦合连接光伏电池板组串1的电能输出端子、逆变器2的电能输入端子、逆变器2中的逆变单元21的电能输入端、逆变器2的电能输入端子与逆变单元21的电能输入端之间的回路，在另一种实现方式中，电压补偿装置3的电能输出端子的另一极也可以同时耦合连接光伏电池板组串1的电能输出端子、逆变器2的电能输入端子、逆变器2中的逆变单元21的电能输入端、逆变器2的电能输入端子与逆变单元21的电能输入端之间的回路中的任意两个或两个以上的位置。
图4以电压补偿装置3的电能输出端子的正极耦合连接光伏电池板组串1的电能输入端子为例，在本实施例中，光伏电池板组串1的电能输入端子包括电能输入端子的器件以及该器件与逆变器2的电能输入端子之间的回路。这样，如图4中较粗的虚线所示，电压补偿装置3的电能输出端子的正极与光伏电池板组串1的电能输出端子之间的通路、分压电路11、PE、电压补偿装置3的电能输出端子的负极与N线之间的通路、N线与PE之间的通路形成电压补偿回路，电压补偿装置3从电网4中获取电能之后，可以通过该电压补偿回路将获取到的电能施加在光伏电池板组串1的电能输出端子与PE之间，从而实现对光伏电池板组串1的电能输出端子与PE之间偏置电压的电压补偿，进而降低PID效应对光伏电池板组串1的影响。
电压补偿装置3的电能输出端子通过耦合连接电网4的N线实现接地，就可以无需通过逆变器2的外壳22接地，这样，即使工作人员忘记将逆变器2的外壳22接地，或者外壳22的接地线出现故障等问题时，如果用户不小心接触逆变器2的外壳22，也不会通过人体形成电压补偿回路，电网4接入电压补偿回路的电流也不会经过人体，也就不会对人身安全造成危害。而且，即使逆变器2不能接地，也不会影响电压补偿装置3对偏置电压的电压补偿效果，从而保证消除PID效应的质量。
进一步地，电压补偿装置3的电能输出端子通过耦合连接电网4的N线可以实现接地，从而无需额外接线实现接地，这样，不仅可以减轻接线工作量和成本，同时，也可以避免额外的接地线带来的安全隐患。
电压补偿装置3通过电能输入端子耦合连接逆变器2的电能输出端子或者耦合连接位于逆变器2外部的电网4进行取电，图4以电压补偿装置3的电能输入端子耦合连接位于逆变器2外部的电网4进行取电为例。
如果电网4为ABC相电网，则如图4所示，逆变器2为三相逆变器，电压补偿装置3的电能输入端子可以通过耦合连接电网4中的ABC三相中的任一一相和电网中的N线实现取电，具体如下：
在一种实现方式中，如图4所示，为电压补偿装置3通过一相从电网4中取电的示例，可见，电压补偿装置3的电能输入端子中的一个电能输入端子耦合连接电网4的ABC相中的C相，电压补偿装置3的电能输入端子中的另一个电能输入端子耦合连接电网4的N线，实现在CN之间取电。此外，电压补偿装置3的电能输入端子中的一个电能输入端子也可以通过耦合连接A相或者B相，另一个电能输入端子耦合连接N线，实现从AN或者BN之间取电。在一种实现方式中，图5为本发明实施例提供的一种通过耦合连接电网中的两相获取电能的结构示意图，图5仅表示电压补偿装置3的电能输入端子与电网4之间的耦合连接关系，光伏发电系统中的其余结构可以参见图4，此图中不做描述。如图5所示，电压补偿装置3的电能输入端子中的一个电能输入端子耦合连接电网4中的B相，电压补偿装置3的电能输入端子中的另一个电能输入端子耦合连接电网4中的C相，这样，电压补偿装置3可以从BC之间取电。此外，电压补偿装置3的电能输入端子中的电能输入端子还可以分别耦合连接ABC相中的任意两相，实现从AB、AC之间取电。进一步地，电压补偿装置3还可以在耦合连接ABC相中任意两相的基础上，耦合连接电网4的N线，实现从ABN、ACN、BCN之间取电，其中，电压补偿装置3也可以依据实际情况选择不连接N线。
在一种实现方式中，图6为本发明实施例提供的一种通过耦合连接电网中的三相获取电能的结构示意图，图6仅表示电压补偿装置3的电能输入端子与电网4之间的耦合连接关系，光伏发电系统中的其余结构可以参见图4，此图中不做描述。如图6所示，电压补偿装置3的电能输入端子中的三个电能输入端子分别耦合连接电网4中的A、B、C三相，这样，电压补偿装置3可以从ABC之间取电。此外，电压补偿装置3还可以在耦合连接ABC相的基础上，耦合连接电网4的N线，实现从ABCN之间取电。
如果电网为LN相电网，则如图7所示，光伏发电系统中的其余结构可以参见图4，此图中不做描述，电压补偿装置3的电能输入端需要连接电网的L相与N线。
电压补偿装置3的电能输入端子与电网4的具体连接方式，可以根据实际需求进 行选取，当电压补偿装置3与逆变器2为两个独立器件时，这样，电压补偿装置3的接线方式可以更加灵活。
光伏电池板组串1可以根据实际需要采用相应的类型，例如P型光伏电池板组串、N型光伏电池板组串。对于不同类型的光伏电池板组串1，其与PE之间存在的偏置电压的类型也不同，因此，用于补偿所产生的偏置电压的补偿电压的类型也就不同。例如：如果光伏电池板组串1为P型光伏电池板组串，则通常光伏电池板组串1的电能输出端子与PE之间存在为负向电压的偏置电压；对于大部分N型光伏电池板组串，通常光伏电池板组串1的电能输出端子与PE之间也存在为负向电压的偏置电压；但是，对于少数N型光伏电池板组串，也会有光伏电池板组串1的电能输出端子与PE之间存在为正向电压的偏置电压。
为了能够准确补偿光伏电池板组串1的电能输出端子对PE产生的偏置电压，就需要保证电压补偿装置3采用相适应的接线方式，以满足与偏置电压相匹配的补偿电压的类型，具体如下：
在一种实现方式中，如果光伏电池板组串1对应的类型为P型或者大部分N型光伏电池板组串，则说明光伏电池板组串1的电能输出端子对PE产生为负向电压的偏置电压，根据PID可逆原理，此时需要的补偿电压为正向电压。那么，为了获得为正向电压的补偿电压，需要电压补偿装置3的电能输出端子的正极耦合连接光伏电池板组串1的电能输出端子，和/或逆变器2的电能输入端子，和/或逆变器2中逆变单元21的电能输入端，和/或逆变器2的电能输入端子与逆变单元21的电能输入端之间的回路。例如，图4以电压补偿装置3的电能输出端子的正极耦合连接光伏电池板组串1的电能输出端子的负极PV-，再由电压补偿装置3的电能输出端子的负极耦合连接电网4的N线为例，此时，由电压补偿装置3的电能输出端子的正极与光伏电池板组串1的电能输出端子的负极PV-之间的通路、分压电路11、PE、电压补偿装置3的电能输出端子的负极与N线之间的通路、N线与PE之间的通路形成电压补偿回路，进而可以通过该电压补偿回路将电能施加在光伏电池板组串1的电能输出端子的PV-与PE之间，在光伏电池板组串1的电能输出端子的PV-与PE之间形成正向电压，从而利用该正向电压对光伏电池板组串1的电能输出端子的PV-与PE之间的偏置电压起到补偿的作用。
其中，当电压补偿装置3的电能输出端子的正极耦合连接光伏电池板组串1的电能输出端子时，可以耦合连接光伏电池板组串1的电能输出端子的正极PV+、负极PV-或者同时耦合连接正极和负极；当电压补偿装置3的电能输出端子的正极耦合连接逆变器2的电能输入端子时，可以耦合连接逆变器2的电能输入端子的正极、负极、或者同时耦合连接正极和负极；当电压补偿装置3的电能输出端子的正极耦合连接逆变器2中逆变单元21的电能输入端时，可以耦合连接逆变单元21的电能输入端的正极、负极、或者同时耦合连接逆变单元21的电能输入端的正极和负极；当电压补偿装置3的电能输出端子的正极耦合连接逆变器2的电能输入端子与逆变单元21的电能输入端之间的回路时，可以耦合连接逆变器2的电能输入端子的正极对应的回路、负极对应的回路或者同时耦合连接正极与负极对应的回路。
在另一种实现方式中，如果光伏电池板组串1对应的类型为少数N型光伏电池板 组串，则说明光伏电池板组串1的电能输出端子对PE产生为正向电压的偏置电压，根据PID可逆原理，此时需要的补偿电压为负向电压。图8为本发明实施例提供的一种光伏发电系统的结构示意图，如图8所示，为了获得负向电压的补偿电压，需要电压补偿装置3的电能输出端子的负极耦合连接光伏电池板组串1的电能输出端子，和/或逆变器2的电能输入端子，和/或逆变器2中逆变单元21的电能输入端，和/或逆变器2的电能输入端子与逆变单元21的电能输入端之间的回路。
图8中以耦合连接光伏电池板组串1的电能输出端子的负极PV-为例，再由电压补偿装置3的电能输出端的正极耦合连接电网4的N线。此时，由电压补偿装置3的电能输出端子的负极与光伏电池板组串1的电能输出端子的负极PV-之间的通路、分压电路11、PE、电压补偿装置3的电能输出端子的正极与N线之间的通路、N线与PE之间的通路形成电压补偿回路，进而可以通过该电压补偿回路将得到的电能施加在光伏电池板组串1的电能输出端子的PV-与PE之间，在光伏电池板组串1的电能输出端子的PV-与PE之间形成负向电压，从而利用该负向电压对光伏电池板组串1的电能输出端子的PV-与PE之间的偏置电压起到补偿的作用。
可选地，也可以将电压补偿装置3的电能输出端的负极耦合连接在如上一实现方式中所提供的耦合连接位置，此处不再赘述。
实施例2
图9为本发明实施例提供的一种光伏发电系统的结构示意图，实施例2与实施例1的主要区别在于，如图9所示，在逆变装置7中，电压补偿装置3与逆变单元21等组件一同封装于逆变器2的外壳22内部，这样，逆变器2相当于一个带有电压补偿功能的逆变器，此时，电压补偿装置3与逆变器2中各器件和耦合回路之间的接线为逆变器2的内部接线，电压补偿装置3与光伏电池板组串1的电能输出端子之间的接线为逆变器2的外部接线，此时，只要用户选择具有合适的内部接线结构的逆变器2，在使用逆变器2时，就可以节省逆变器2内部的接线操作，只需要进行逆变器2的外部接线操作即可。
本实施例提供的光伏发电系统包括光伏电池板组串1和逆变装置7，所述逆变装置7包括逆变器2和电压补偿装置3；所述光伏电池板组串1的电能输出端子耦合连接所述逆变器2的电能输入端子；所述逆变器2的电能输出端子耦合连接电网4；所述电压补偿装置3的电能输入端子耦合连接所述电网4，用于从所述电网4获取电能；所述电压补偿装置3的电能输出端子的一极可以耦合连接所述光伏电池板组串1的电能输出端子，和/或所述逆变器2的电能输入端子，和/或所述逆变器2中的逆变单元21的电能输入端，和/或所述逆变器2的电能输入端子与所述逆变单元21的电能输入端之间的回路。在一种实现方式中，电压补偿装置3的电能输出端子的一极可以只耦合连接光伏电池板组串1的电能输出端子、逆变器2的电能输入端子、逆变器2中的逆变单元21的电能输入端、逆变器2的电能输入端子与逆变单元21的电能输入端之间的回路。在另一种实现方式中，电压补偿装置3的电能输出端子的一极也可以同时耦合连接光伏电池板组串1的电能输出端子、逆变器2的电能输入端子、逆变器2中的逆变单元21的电能输入端、逆变器2的电能输入端子与逆变单元21的电能输入端之间的回路中的任意两个或两个以上的位置。
图9以电压补偿装置3的电能输出端子的一极耦合连接逆变器2中的逆变单元21的电能输入端，例如耦合连接直流母线，所述电压补偿装置3的电能输出端子的另一极耦合连接所述电网4的N线为例，这样可以将从所述电网4获取的电能施加在所述光伏电池板组串的电能输出端子与大地之间。
对应于本实施例，图10为本发明实施例提供的一种逆变器的结构示意图，图10所提供的逆变器将电压补偿装置的接线全部设置为逆变器的内部接线，如图10所示，逆变器2包括：逆变单元21、外壳22、并网开关单元23、电能输入端子24、电能输出端子25和电压补偿装置3，还可以包括DC/DC直流变压单元26。其中，电能输入端子24、电能输出端子25设置于外壳22上，电能输入端子24用于耦合连接光伏电池板组串1的电能输出端子，电能输出端子25用于耦合连接电网4，逆变单元21的电能输入端耦合连接电能输入端子24，当存在DC/DC直流变压单元26时，电能输入端子24耦合连接DC/DC直流变压单元26的电能输入端，DC/DC直流变压单元26的电能输出端耦合连接逆变单元21的电能输入端，其中，DC/DC直流变压单元26用于接收光伏电池板组串1传输的直流电，并将该直流电逆变为电压符合标准的电压，进而将逆变后的直流电传输至逆变单元21，逆变单元21的电能输出端通过并网开关单元23耦合连接电能输出端子25。
逆变器2通过电能输入端子24与光伏电池板组串1的电能输出端子耦合连接，以接收光伏电池板组串1输入的电能。逆变器2通过电能输出端子25与电网4耦合连接，以将逆变后的电流输入电网4。逆变器中还包含并网开关单元23，并网开关单元23设置于逆变单元21的电能输出端与电能输出端子25之间的耦合回路上，用于控制逆变单元21与电网4之间的连接与断开。另外，为了满足逆变器2的正常工作需要，逆变器2中还可以包括其它组件，例如电容、电感等，本实施例中不一一展示。
在实施例2中，电压补偿装置3的取电连线方式为：如图10所示，电压补偿装置3的电能输入端子耦合连接并网开关单元23与电能输出端子25之间的回路。与实施例1的区别在于，实施例2中所提供的电压补偿装置3的取电接线方式为逆变器2的内部接线，因此，用户在安装该逆变器时，可以省略电压补偿装置3与电网4之间的接线操作，只需要根据实际的连线需要，选择对应的逆变器产品。
电压补偿装置3的电能输出端子的一极可以耦合连接与电网4的N线耦合连接的电能输出端子,和/或耦合连接与电网4的N线耦合连接的电能输出端子在逆变器2内对应的耦合回路，图10以电压补偿装置3的电能输出端子的一极耦合连接与电网4的N线耦合连接的电能输出端子在逆变器2内对应的耦合回路为例。
电压补偿装置3的电能输出端子的另一极可以耦合连接逆变器2的电能输入端子，和/或逆变器2中的逆变单元21的电能输入端，和/或逆变器2的电能输入端子与逆变单元21的电能输入端之间的回路。例如，图11给出了以电压补偿装置3的电能输出端子的另一极耦合连接电能输入端子24的示例，图9给出了电压补偿装置3的电能输出端子的另一极耦合连接逆变器2中的逆变单元21的电能输入端的示例，例如连接直流母线，其中，DC/DC直流变压单元26与逆变单元21之间的耦合连接线称为直流母线(BUS)，DC/DC直流变压单元26的电能输出端的正极与逆变单元21之间的耦合连接线即为BUS+，DC/DC直流变压单元26的电能输出端的负极与逆变单元21之间的耦 合连接线即为BUS-。图12给出了以电压补偿装置3的电能输出端子的另一极耦合连接逆变器2的电能输入端子与逆变单元21的电能输入端之间的回路的示例，图12中不具体公开DC/DC直流变压单元26的内部连线结构，仅通过DC/DC直流变压单元26代表逆变器2的电能输入端子与逆变单元21的电能输入端之间的回路。其中，与电压补偿装置3的电能输出端子采用哪一极与上述耦合接线对象的哪一极进行连接的具体选择方法可以参见实施例1中的描述，此处不再赘述。
在实施例2中，逆变器2也可以根据电网的类型选择如图10所示的三相逆变器，也可以选择如图13所示的单相逆变器。例如电网为ABC相类型，则选择三相逆变器，电网为LN相类型，则选择单相逆变器。
在实施例1和实施例2中，电压补偿装置3包括功率变换模块，功率变换模块分别与电压补偿装置3的电能输入端子和电压补偿装置3的电能输出端子耦合，用于将从电网4获取的电能变换为可供光伏电池板组串1侧适用的电流类型，在一种实现方式中，功率变换模块为AC/DC变换单元，这样，可以将从电网4获取到的交流电变换为光伏电池板组串1侧电路适用的直流电。进一步地，功率变换模块为隔离AC/DC变换单元，这样，可以有效隔离电网4与光伏电池板组串1，进而降低电网4对光伏电池板组串1的干扰和影响，从而提高光伏电池板组串1的使用稳定性和安全性，有效实现电流类型的转换。
在实施例1与实施例2中提到的耦合连接可以为直接耦合连接、通过开关器件耦合连接、通过限流组件耦合连接、通过开关器件和限流组件耦合连接中的任意一种连接方式。其中，直接耦合连接即两个器件之间直接通过连线连接；通过开关器件耦合连接，即两个器件之间通过连线连接，并且通过开关器件进行连接与断开的控制；通过限流组件耦合连接，即两个器件之间通过连线连接，并且通过限流组件来限制两个器件之间流通的电流值，从而保护两个电路及器件的安全性；通过开关器件和限流组件耦合连接，即两个器件之间通过连线连接，并通过开关器件进行连接与断开的控制，同时通过限流组件来限制两个器件之间流通的电流值。用户可以根据实际使用需求选择适合的耦合连接方式，此处不做限制。
可选的，所述开关器件可以为半导体开关、继电器、接触器、断路器、机械开关中的一种或者几种的组合。限流组件可以为电阻、电感或者限流电路。
在实施例1和实施例2中，功率变换模块中还可以包括用于辅助AC/DC变换单元实现功率变换功能的组件，例如开关、电阻等，AC/DC变换单元与这些组件之间可以采用多种接线方式，并最终与电压补偿装置3的电能输入端子以及电能输出端子耦合(为简便描述，下文将省略描述功率变换模块的内部组件与电能输出端子32之间的耦合连接，简化为功率变换模块的内部组件与电网4之间的对应关系)，具体如下：
在一种实现方式中，图14为本发明实施例提供的一种功率变换模块的内部结构示意图，如图14所示，所述功率变换模块包括AC/DC变换单元、第一开关、第二开关、第三开关和第四开关(图14中第一开关-第四开关分别对应K1-K4，其中，第一、第二、第三、第四的描述只为方便说明，并不限定具体的功能，也不会对方案的保护范围构成限制)。其中，图14对应的电网4为ABC相电网，AC/DC变换单元的电能输入端通过第一开关与电压补偿装置3的电能输出端子中与电网ABC相耦合连接的电能输 出端子耦合，AC/DC变换单元的电能输入端通过第二开关与电压补偿装置3的电能输出端子中与电网4中的N线耦合连接的电能输出端子耦合，如图14所示，AC/DC变换单元的电能输入端分别耦合与电网4中的B相和N线耦合连接的电压补偿装置3的电能输出端子(如果电网为LN相电网，则AC/DC变换单元的电能输入端通过第一开关与电网4中的L相耦合连接，并且通过第二开关与电网4中的N线耦合连接)，从而可以实现从电网4中取电。如图14所示，AC/DC变换单元与其它器件的耦合连接为通过开关器件耦合连接，这样，可以通过K1-K4对不同的连接线路进行连通和断开的控制。值得注意的是，第一开关的数量可以为1个或者多个，第一开关的具体数量与功率变换模块31耦合连接的电网4类型，以及接线取电类型相关，例如，如果电网4为LN相电网，则第一开关为1个，且设置在AC/DC变换单元的输入端子与电网4的L相的连线上，此时，第二开关为连通状态；如果电网4为ABC型电网，且采用的接线取电类型为从BC相之间取电，则第一开关为2个，且分别设置在AC/DC变换单元的电能输入端与电网4的B相和C相的连线上，此时，第二开关为断开状态；又或者接线取电类型为从BN相之间取电，则如图14所示，第一开关为1个，且设置在AC/DC变换单元的电能输入端与电网4的B相的连线上，第二开关为连通状态。保证AC/DC变换单元的电能输入端与电压补偿装置3的电能输出端子之间用于取电的每一条连线上均设置对应的第一开关，这样，可以通过每一个第一开关控制其所在连线的连通和断开，从而有效控制电流的流通，以及防止电流异常等问题对光伏发电系统的损害。
进一步地，AC/DC变换单元也可以与和电网4中的各相对应的电压补偿装置3的电能输出端子之间均建立连线，并通过每一条连线上设置的第一开关实现该条线路的连通和断开，以控制取电的相。
AC/DC变换单元的电能输出端的一极通过第三开关与电压补偿装置3的电能输入端子耦合，这样，可以通过控制第三开关来控制AC/DC变换单元与电压补偿装置3的电能输入端子之间的连通与断开，进而可以在AC/DC变换单元或者电网4出现异常时，可以及时断开与光伏电池板组串1之间的耦合连接，从而保护光伏电池板组串1一侧组件的安全。
AC/DC变换单元的电能输出端的另一极通过所述第四开关与电网4的N线耦合连接，从而实现接地。
在一种情况中，如图14所示，AC/DC变换单元的电能输出端接入电网4的N线的耦合连接点在AC/DC变换单元与第二开关之间的连线上。这样，可以通过一个开关，即第二开关，实现同时对取电和接地形成电压补偿回路两个线路的连通与断开的控制，这样，在线路出现故障等较为紧急的情况下，可以更加快速及时地控制电路。
在另一种情况中，图15为本发明实施例提供的一种功率变换模块的内部结构示意图，图15与图14的区别在于，DC/AC变换单元的电能输出端接入电网4的N线的耦合连接点在第二开关与电网4的N线的耦合连接线上。可见，第二开关仅控制AC/DC变换单元与电网4之间取电的连通和断开，在这种情况下，可以有效实现对取电和接地形成电压补偿回路两个线路的连通与断开的控制的解耦，令第二开关的控制更加有针对性。
结合上文对开关器件的选择，本实施例中的第一开关、第二开关、第三开关和第 四开关也可以根据实际需求，例如安装方式、控制方式、空间占用量、成本、安全性等，采用半导体开关、继电器、接触器、断路器、机械开关中的一种或者几种的组合。例如，如果想要提高控制的自动化，就可以采用继电器。
在如图14和图15所示的功率变换模块中，如果从电网4接入的电能较高，在AC/DC变换单元、第四开关形成的回路，或者AC/DC变换单元、第四开关、第二开关形成的回路中，就会一直流通较高的电能，对回路中的组件造成多次损伤。图16为本发明提供的一种功率变换模块的内部结构示意图，如图16所示，为了降低对各组件的损伤，可以采用通过限流组件的耦合连接方式，即在AC/DC变换单元与电网4的N线之间设置限流组件，以降低从各个组件中流过的电流，保护各个组件。其中，如图16所示，限流组件可以设置于第四开关与电网的N线之间，当然，限流组件也可以设置于第四开关与AC/DC变换单元之间。结合上文对限流组件的选择，可以根据实际需求，选择电阻、电感、限流电路中的任一种作为限流组件，在图16中选择电阻作为限流组件。
在实施例1和实施例2的基础上，为了提高光伏发电系统的工作效率和质量，可以在光伏发电系统内增设控制器，图17为本发明实施例提供的一种带有控制器的光伏发电系统的结构示意图，如图17所示，图17以逆变器2和电压补偿装置3为两个独立器件的光伏发电系统为例，控制器5分别与逆变器2和电压补偿装置3耦合通信。如果光伏电池板组串1产生电能，则说明光伏电池板组串1处于工作状态，此时，光伏发电系统处于发电工作情况，不能进行电压补偿操作，因此，控制器5控制开启逆变器2，并关闭电压补偿装置3；如果光伏电池板组串1未产生电能，则说明光伏电池板组串1未处于工作状态，此时，可以对光伏电池板组串1进行电压补偿操作，因此，控制器5控制关闭逆变器2，并开启电压补偿装置3。这样，可以通过控制器5对光伏发电系统实现自动控制，以减轻人力，同时提高光伏发电系统的工作效率和质量。
基于实施例2，为了提高逆变器2对电压补偿过程的自动控制，如图18所示，在逆变器2中设置有控制单元6，控制单元6分别与逆变单元21、所述DC/DC直流变压单元26、所述并网开关单元23、所述电压补偿装置3耦合。这样就可以通过控制单元6实现对逆变单元21、DC/DC直流变压单元26、并网开关单元23以及电压补偿装置3的自动控制，从而提高对逆变器2的控制精确度。当然，如果逆变器2中包含控制单元6，那么控制单元6也与控制器5耦合通信，并受到控制器5的控制。
以上的具体实施方式，对本发明的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上仅为本发明的具体实施方式而已，并不用于限定本发明的保护范围，凡在本发明的技术方案的基础之上，所做的任何修改、等同替换、改进等，均应包括在本发明的保护范围之内。

Claims (15)

  1. 一种电压补偿装置，包括功率变换模块，所述功率变换模块分别耦合连接所述电压补偿装置的电能输入端子和所述电压补偿装置的电能输出端子，其特征在于，
    所述电压补偿装置的电能输入端子耦合连接电网，用于从所述电网获取电能；
    所述电压补偿装置的电能输出端子的一极耦合连接光伏电池板组串的电能输出端子，和/或逆变器的电能输入端子，和/或所述逆变器中逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的另一极耦合连接所述电网的N线，用于将从所述电网获取的电能施加在所述光伏电池板组串的电能输出端子与大地之间。
  2. 根据权利要求1所述的电压补偿装置，其特征在于，如果所述电压补偿装置设置于所述逆变器的内部，则所述电压补偿装置的电能输入端子耦合连接所述逆变器内并网开关单元与所述逆变器的电能输出端子之间的回路。
  3. 根据权利要求1所述的电压补偿装置，其特征在于，如果所述电压补偿装置设置于所述逆变器的外部，则所述电压补偿装置的电能输入端子耦合连接所述逆变器的电能输出端子或者耦合连接位于所述逆变器外部的电网。
  4. 根据权利要求1-3中任一所述的电压补偿装置，其特征在于，所述电压补偿装置的电能输入端子分别耦合连接所述电网的ABC相中至少一相和所述电网的N线；
    或者，所述电压补偿装置的电能输入端子连接所述电网的ABC相中至少两相；
    或者，所述电压补偿装置的电能输入端子耦合连接所述电网的L相与所述电网的N线。
  5. 根据权利要求1-4中任一所述的电压补偿装置，其特征在于，如果所述光伏电池板组串对应的补偿电压为正向电压，则所述电压补偿装置的电能输出端子的正极耦合连接所述光伏电池板组串的电能输出端子，和/或所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的负极耦合连接所述电网的N线；
    或者，如果所述光伏电池板组串对应的补偿电压为负向电压，则所述电压补偿装置的电能输出端子的负极耦合连接所述光伏电池板组串的电能输出端子，和/或所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的正极耦合连接所述电网的N线。
  6. 根据权利要求1-5中任一所述的电压补偿装置，其特征在于，所述功率变换模块为隔离AC/DC变换单元。
  7. 根据权利要求1-6中任一所述的电压补偿装置，其特征在于，耦合连接为直接耦合连接、通过开关器件耦合连接、通过限流组件耦合连接、通过开关器件和限流组件耦合连接中的至少一种连接方式。
  8. 根据权利要求7所述的电压补偿装置，其特征在于，所述开关器件为半导体开关、继电器、接触器、断路器、机械开关中的一种或者几种的组合。
  9. 根据权利要求7或8所述的电压补偿装置，其特征在于，所述限流组件为电 阻、电感或者限流电路。
  10. 一种逆变装置，其特征在于，所述逆变装置包括：逆变器和如权利要求1-2、4-9中任一所述的电压补偿装置；
    所述逆变器包括外壳、电能输入端子、电能输出端子、逆变单元和并网开关单元；
    所述电能输入端子和所述电能输出端子设置于所述外壳上，所述电能输入端子用于耦合连接光伏电池板组串的电能输出端子，所述电能输出端子用于耦合连接电网；
    所述逆变单元、所述并网开关单元和所述电压补偿装置均设置于所述逆变器的内部；
    所述逆变单元的电能输入端耦合连接所述电能输入端子；
    所述逆变单元的电能输出端通过所述并网开关单元耦合连接所述电能输出端子；
    所述电压补偿装置的电能输入端子耦合连接所述并网开关单元与所述电能输出端子之间的回路；
    所述电压补偿装置的电能输出端子的一极耦合连接与所述电网的N线耦合连接的电能输出端子,和/或耦合连接与所述电网的N线耦合连接的电能输出端子在所述逆变器内对应的耦合回路，所述电压补偿装置的电能输出端子的另一极耦合连接所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述电能输入端子与所述逆变单元的电能输入端之间的回路。
  11. 根据权利要求10所述的逆变装置，其特征在于，如果所述光伏电池板组串对应的补偿电压为正向电压，则所述电压补偿装置的电能输出端子的正极耦合连接所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的负极耦合连接与所述电网的N线耦合连接的电能输出端子,和/或耦合连接与所述电网的N线耦合连接的电能输出端子在所述逆变器内对应的耦合回路；
    或者，如果所述光伏电池板组串对应的补偿电压为负向电压，则所述电压补偿装置的电能输出端子的负极耦合连接所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的正极耦合连接与所述电网的N线耦合连接的电能输出端子,和/或耦合连接与所述电网的N线耦合连接的电能输出端子在所述逆变器内对应的耦合回路。
  12. 根据权利要求10或11所述的逆变装置，其特征在于，所述逆变器还包括DC/DC直流变压单元；
    所述DC/DC直流变压单元的输入端子耦合连接所述电能输入端子；
    所述DC/DC直流变压单元的输出端子耦合连接所述逆变单元的输入端子。
  13. 根据权利要求12所述的逆变装置，其特征在于，所述逆变器还包括控制单元；
    所述控制单元分别与所述逆变单元、所述DC/DC直流变换单元、所述并网开关单元和所述电压补偿装置耦合连接。
  14. 一种光伏发电系统，其特征在于，所述光伏发电系统包括：光伏电池板组串 和逆变装置，所述逆变装置包括逆变器和如权利要求1-9中任一所述的电压补偿装置；
    所述光伏电池板组串的电能输出端子耦合连接所述逆变器的电能输入端子；
    所述逆变器的电能输出端子耦合连接电网；
    所述电压补偿装置的电能输入端子耦合连接所述电网，用于从所述电网获取电能；
    所述电压补偿装置的电能输出端子的一极耦合连接所述光伏电池板组串的电能输出端子，和/或所述逆变器的电能输入端子，和/或所述逆变器中的逆变单元的电能输入端，和/或所述逆变器的电能输入端子与所述逆变单元的电能输入端之间的回路，所述电压补偿装置的电能输出端子的另一极耦合连接所述电网的N线，用于将从所述电网获取的电能施加在所述光伏电池板组串的电能输出端子与大地之间。
  15. 根据权利要求14所述的光伏发电系统，其特征在于，所述光伏发电系统还包括控制器；
    所述控制器分别与所述逆变器和所述电压补偿装置耦合通信。
PCT/CN2021/087595 2020-07-24 2021-04-15 一种电压补偿装置、逆变装置及光伏发电系统 WO2022016919A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP21845320.7A EP4184743A4 (en) 2020-07-24 2021-04-15 VOLTAGE COMPENSATION DEVICE, REVERSAL DEVICE AND PHOTOVOLTAIC ELECTRICITY GENERATION SYSTEM
US18/156,558 US20230155382A1 (en) 2020-07-24 2023-01-19 Voltage compensation apparatus, inverter apparatus, and photovoltaic power generation system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202010721883.0 2020-07-24
CN202010721883.0A CN111969646B (zh) 2020-07-24 2020-07-24 一种电压补偿装置、逆变装置及光伏发电系统

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/156,558 Continuation US20230155382A1 (en) 2020-07-24 2023-01-19 Voltage compensation apparatus, inverter apparatus, and photovoltaic power generation system

Publications (1)

Publication Number Publication Date
WO2022016919A1 true WO2022016919A1 (zh) 2022-01-27

Family

ID=73362632

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/087595 WO2022016919A1 (zh) 2020-07-24 2021-04-15 一种电压补偿装置、逆变装置及光伏发电系统

Country Status (4)

Country Link
US (1) US20230155382A1 (zh)
EP (1) EP4184743A4 (zh)
CN (2) CN115085263A (zh)
WO (1) WO2022016919A1 (zh)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115085263A (zh) * 2020-07-24 2022-09-20 华为数字能源技术有限公司 一种逆变装置及光伏发电系统
CN115575852A (zh) * 2022-10-11 2023-01-06 华为数字能源技术有限公司 一种机壳接地检测方法及逆变器

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203166494U (zh) * 2013-03-26 2013-08-28 阳光电源（上海）有限公司 一种解决电势诱导衰减的装置
CN105871324A (zh) * 2016-04-11 2016-08-17 厦门科华恒盛股份有限公司 一种多路输入光伏逆变系统的独立mppt跟踪方法
EP3337022A1 (en) * 2016-12-15 2018-06-20 DET International Holding Limited Control of a multiple input solar power inverter
CN110932667A (zh) * 2019-12-13 2020-03-27 阳光电源股份有限公司 一种双极性的pid修复装置及光伏系统
CN111969646A (zh) * 2020-07-24 2020-11-20 华为技术有限公司 一种电压补偿装置、逆变装置及光伏发电系统

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203218893U (zh) * 2013-04-24 2013-09-25 阳光电源（上海）有限公司 一种解决电势诱导衰减的设备
CN103326398B (zh) * 2013-06-09 2016-01-20 阳光电源（上海）有限公司 电压补偿装置及包含该装置的变流器、光伏发电系统
CN103337874B (zh) * 2013-06-09 2015-05-20 阳光电源股份有限公司 光伏发电系统及应用于该系统的电压补偿装置、变流器
CN104201981B (zh) * 2014-09-25 2017-01-11 阳光电源股份有限公司 一种反电势诱导衰减的控制方法及控制系统
CN106463967B (zh) * 2014-09-30 2019-04-09 阳光电源股份有限公司 一种并网逆变器安全检测装置及方法
CN107086601B (zh) * 2017-05-18 2020-04-21 华为技术有限公司 一种光伏发电系统及电压补偿方法
JP7101333B2 (ja) * 2018-04-05 2022-07-15 日新電機株式会社 電源システム
CN109638808A (zh) * 2018-12-21 2019-04-16 华为数字技术（苏州）有限公司 电势诱导衰减的补偿电路、方法、功率模块及光伏系统

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203166494U (zh) * 2013-03-26 2013-08-28 阳光电源（上海）有限公司 一种解决电势诱导衰减的装置
CN105871324A (zh) * 2016-04-11 2016-08-17 厦门科华恒盛股份有限公司 一种多路输入光伏逆变系统的独立mppt跟踪方法
EP3337022A1 (en) * 2016-12-15 2018-06-20 DET International Holding Limited Control of a multiple input solar power inverter
CN110932667A (zh) * 2019-12-13 2020-03-27 阳光电源股份有限公司 一种双极性的pid修复装置及光伏系统
CN111969646A (zh) * 2020-07-24 2020-11-20 华为技术有限公司 一种电压补偿装置、逆变装置及光伏发电系统

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4184743A4

Also Published As

Publication number Publication date
CN115085263A (zh) 2022-09-20
CN111969646B (zh) 2022-07-22
US20230155382A1 (en) 2023-05-18
EP4184743A4 (en) 2024-01-31
CN111969646A (zh) 2020-11-20
EP4184743A1 (en) 2023-05-24

Similar Documents

Publication Publication Date Title
WO2022016919A1 (zh) 一种电压补偿装置、逆变装置及光伏发电系统
US20140177293A1 (en) Distribution transformer interface apparatus and methods
US20220360106A1 (en) Providing Positional Awareness Information and Increasing Power Quality of Parallel Connected Inverters
WO2014047327A1 (en) Serially connected micro-inverter system with trunk and drop cabling
US20230046346A1 (en) Power System
US20220200290A1 (en) Power System
TW200533039A (en) Power converter of a hybrid power filter
CN203984337U (zh) 一种小型光伏汇流箱
US11955836B2 (en) Power device terminal backup switch unit
CN106684927A (zh) 一种孤网系统中大型发电机组并网系统及并网方法
EP4068548B1 (en) Direct current power supply system, photovoltaic system and energy storage system
US10116204B1 (en) Distribution transformer interface apparatus and methods
WO2022170578A1 (zh) 逆变装置及逆变系统
TWI443927B (zh) 具相位切換裝置之線材系統
CN112491089A (zh) 一种微网并离网混合切换系统及方法
JPS6350941B2 (zh)
US10992168B2 (en) Apparatus of power distribution and method of power distribution
CN217607699U (zh) 一种三相并网星接链式换流器的缓启动装置
WO2023210326A1 (ja) 電源システム
CN113241734B (zh) 一种光伏面板负极接地检测及保护装置
CN221227378U (zh) 一种海上模块式逆变器
CN213879668U (zh) 无功变流器
CN211579928U (zh) 一种用于家庭光伏的多功能即插即用装置
WO2022021347A1 (zh) 固态变压器与供电系统
Zhang et al. Research on high permeability photovoltaic access distribution network architecture and protection configuration

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: 21845320

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2021845320

Country of ref document: EP

Effective date: 20230216