WO2022082769A1 - 组串式光伏逆变器反灌缓起电路 - Google Patents

组串式光伏逆变器反灌缓起电路 Download PDF

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Publication number
WO2022082769A1
WO2022082769A1 PCT/CN2020/123400 CN2020123400W WO2022082769A1 WO 2022082769 A1 WO2022082769 A1 WO 2022082769A1 CN 2020123400 W CN2020123400 W CN 2020123400W WO 2022082769 A1 WO2022082769 A1 WO 2022082769A1
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Prior art keywords
current
switch
photovoltaic
converter
feed
Prior art date
Application number
PCT/CN2020/123400
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English (en)
French (fr)
Inventor
曹震
石磊
刘云峰
崇锋
樊华龙
贺佳佳
侯少攀
张�杰
Original Assignee
华为数字能源技术有限公司
国家电投集团青海光伏产业创新中心有限公司
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Application filed by 华为数字能源技术有限公司, 国家电投集团青海光伏产业创新中心有限公司 filed Critical 华为数字能源技术有限公司
Priority to CN202080007538.9A priority Critical patent/CN114667678B/zh
Priority to PCT/CN2020/123400 priority patent/WO2022082769A1/zh
Priority to EP20958351.7A priority patent/EP4220941A4/en
Publication of WO2022082769A1 publication Critical patent/WO2022082769A1/zh
Priority to US18/305,215 priority patent/US20230327543A1/en

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    • 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
    • H02S50/00—Monitoring or testing of PV systems, e.g. load balancing or fault identification
    • H02S50/10—Testing of PV devices, e.g. of PV modules or single PV cells
    • 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
    • H02M1/36—Means for starting or stopping converters
    • 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
    • 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
    • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S50/00—Monitoring or testing of PV systems, e.g. load balancing or fault identification
    • H02S50/10—Testing of PV devices, e.g. of PV modules or single PV cells
    • H02S50/15—Testing of PV devices, e.g. of PV modules or single PV cells using optical means, e.g. using electroluminescence
    • 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
    • H02J2300/26—The renewable source being solar energy of photovoltaic origin involving maximum power point tracking control for photovoltaic sources
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Definitions

  • the present application relates to power electronics technology, and in particular, to a back-feed and slow-start circuit of a string-type photovoltaic inverter.
  • Photovoltaic power generation refers to the use of the photovoltaic effect of semiconductor materials to convert solar radiation energy into electrical energy, such as generating direct current under sunlight through photovoltaic modules.
  • Photovoltaic modules are the core part of photovoltaic power generation systems. Several single solar cells are connected in series and parallel and then packaged into a single module, which is used to convert solar energy into electrical energy, which can also be called photovoltaic cell modules. Since the quality of photovoltaic modules directly determines the power generation performance of the photovoltaic power generation system, and there are factors such as device aging and loss, it is necessary to test the photovoltaic modules in the photovoltaic power generation system.
  • the detection of photovoltaic modules in photovoltaic power generation systems generally utilizes the electroluminescent effect (Electroluminescent, EL).
  • DC reverse current is generated by applying DC voltage to PV modules or PV module strings. Therefore, PV modules will generate a certain intensity of infrared light.
  • Imaging devices such as Charge Coupled Device (CCD) cameras or other photosensitive devices can be used. Capture imaging of infrared light generated by photovoltaic modules. Among them, defective photovoltaic modules show obvious dark spots during imaging, so that defective photovoltaic modules can be identified by using this feature, and then provide a basis for photovoltaic module improvement and photovoltaic power station maintenance.
  • a common practice is to use a rectifier to convert the AC power in the external power supply or mobile power supply into DC power, and transmit the DC power to the PV module through the power port on the PV module, that is, DC reverse current.
  • a string-type photovoltaic inverter directly connects a string-type solution component composed of several photovoltaic components to the inverter.
  • the DC power output by the components of the string scheme is boosted by the DC/DC converter to achieve Maximum Power Point Tracking (MPPT), that is, the power generation voltage is detected in real time and the highest voltage and current value are tracked to achieve maximum power point tracking (MPPT). power output.
  • MPPT Maximum Power Point Tracking
  • the DC voltage boosted by the DC/DC converter is converted into an AC voltage by the DC/AC converter and then integrated into the power grid for transmission.
  • each photovoltaic module is affected by different external factors such as light and environment, and its output power changes differently, multi-channel MPPT and multi-channel DC/DC converters are required to perform power tracking for each photovoltaic module.
  • the DC/DC converter may use a unidirectional boost converter, that is, the reverse transmission of voltage and current cannot be performed. For this reason, when the DC reverse current is supplied to the components of the string solution, the unidirectional DC/DC converter needs to be processed through an external bypass switch, and the bus voltage from the reverse rectification of the DC/AC converter is relatively high. , at the moment of external bypass switch switching, a large inrush current will be generated on the input side of the DC/DC converter, thereby causing damage to the inverter.
  • a string-type photovoltaic inverter that uses a string-type solution to output DC power needs to test multiple photovoltaic modules at the same time, which brings challenges such as large equipment, difficult operation, and safety risks under high-voltage operation.
  • the purpose of the present application is to provide a back-feed slow-start circuit of a photovoltaic inverter.
  • the back-feed buffer circuit is connected between the DC input side of the DC/AC converter of the photovoltaic inverter and the output side of the solar photovoltaic array.
  • the back-feed slow-start circuit includes: a plurality of branch switches, wherein the solar photovoltaic array includes a plurality of photovoltaic components, the plurality of branch switches are in one-to-one correspondence with the plurality of photovoltaic components, and the plurality of When the branch switches are closed, the corresponding photovoltaic modules are connected to the back-feeding slow-start circuit; the main switch, wherein one end of the plurality of branch switches is connected to the corresponding photovoltaic modules and the other ends are connected to the main switch; wherein , the main switch is closed after the branch switch is closed, so that the reverse-injection current generated by the reverse rectification of the DC/AC converter passes through the DC input side of the DC/AC converter and the reverse-injection buffer
  • the start-up circuit is connected to the photovoltaic module connected to the back-feed buffer start-up circuit.
  • an embodiment of the present application provides a back-feed buffer circuit for a photovoltaic inverter.
  • the back-feed buffer circuit is connected between the DC input side of the DC/AC converter of the photovoltaic inverter and the output side of the solar photovoltaic array.
  • the back-feed slow-start circuit includes: a plurality of branch switches, wherein the solar photovoltaic array includes a plurality of photovoltaic components, the plurality of branch switches are in one-to-one correspondence with the plurality of photovoltaic components, and the plurality of When the branch switches are closed, the corresponding photovoltaic modules are connected to the back-feeding slow-start circuit; the main switch, wherein one end of the plurality of branch switches is connected to the corresponding photovoltaic modules and the other ends are connected to the main switch; wherein , the main switch is closed after the branch switch is closed, so that the reverse-injection current generated by the reverse rectification of the DC/AC converter passes through the DC input side of the DC/AC converter and the reverse-injection buffer
  • the start-up circuit is connected to the photovoltaic module connected to the back-feed buffer start-up circuit.
  • the technical solution described in the first aspect by selectively controlling the closing and opening of a plurality of branch switches, is beneficial to flexibly configure the combination and quantity of photovoltaic modules participating in the detection, and at the same time pass the main switch and the branch switches.
  • the operation of the circuit switch can effectively suppress the sudden change of the reverse current so as to avoid the damage of the inverter caused by the inrush current.
  • the back-feed slow-start circuit further includes a current-limiting switch and a current-limiting resistor, wherein the current-limiting switch and the current-limiting resistor are connected in series with the current-limiting resistor.
  • the main switch is connected in parallel, the current limit switch is closed after the branch switch is closed, the main switch is closed after the current limit switch is closed for a first time, and the current limit switch is closed after the main switch The switch is turned off after being closed for a second time, the second time being determined according to the bus voltage on the DC input side of the DC/AC converter.
  • the operation of the main switch, the branch switch and the current limiting switch can effectively suppress the sudden change of the reverse current so as to avoid the damage of the inverter caused by the inrush current, and also maintain the energy utilization efficiency.
  • the back-feed slow-start circuit further includes a current-limiting inductor, and the current-limiting switch and the current-limiting resistor are connected in series with the main switch and then connected in parallel. connected in series with the current limiting inductor.
  • the back-feed slow-start circuit further includes a current-limiting switch and a current-limiting resistor, wherein the current-limiting switch and the current-limiting resistor are connected in parallel with the current-limiting resistor.
  • the main switch is connected in series, the main switch is closed after the branch switch is closed, and the current limiting switch is closed after the main switch is closed for a first time.
  • the operation of the main switch, the branch switch and the current limiting switch can effectively suppress the sudden change of the reverse current so as to avoid the damage of the inverter caused by the inrush current, and also maintain the energy utilization efficiency.
  • the back-feed slow-start circuit further includes a current-limiting inductor, the current-limiting inductor is connected in series with the main switch, and the main switch is in the branch The circuit switch is closed after a first time has elapsed, and the first time is determined according to the inductance value of the current limiting inductor and the quantity of the photovoltaic modules connected to the back-feed buffer circuit.
  • the back-feed slow-up circuit further includes a step-down conversion circuit
  • the step-down conversion circuit includes an inductor and a switch transistor, and the inductor and the switch transistor After being connected in series, it is connected in series with the main switching switch, and the switch tube of the step-down conversion circuit is kept closed under the control of the pulse width modulation signal, so that the reverse current flows through the step-down conversion circuit.
  • the magnitude of the reverse sink current is adjusted according to the bus voltage on the DC input side of the DC/AC converter.
  • the magnitude of the reverse sink current can be dynamically adjusted according to the bus voltage.
  • the bus voltage on the DC input side of the DC/AC converter is adjusted to a minimum value before the detection starts and before the detection ends.
  • the branch switch is turned off after the main switch is turned off, so that the photovoltaic module connected to the reverse irrigation buffer circuit is connected to the inverter.
  • the slow down circuit is disconnected.
  • an embodiment of the present application provides a photovoltaic inverter, the photovoltaic inverter includes a plurality of bidirectional DC/DC converters, and the plurality of bidirectional DC/DC converters are connected to a plurality of solar photovoltaic arrays A photovoltaic assembly, wherein the photovoltaic inverter applies the reverse rectified voltage to the corresponding photovoltaic assembly through the pulsed control of the plurality of bidirectional DC/DC converters under the pulse width modulation signal.
  • the technical solution described in the second aspect effectively suppresses the sudden change of the reverse current by controlling a plurality of bidirectional DC/DC converters.
  • embodiments of the present application provide a method for electroluminescence detection of a solar photovoltaic array, where the solar photovoltaic array includes a plurality of photovoltaic components, and a photovoltaic inverter connected to the solar photovoltaic array includes a DC/ AC converter, a back-feed buffer circuit is connected between the DC input side of the DC/AC converter of the photovoltaic inverter and the output side of the solar photovoltaic array, and the back-feed buffer circuit includes a
  • the plurality of photovoltaic modules are in one-to-one correspondence with a plurality of branch switches and a main switch, and one end of the plurality of branch switches is connected to the corresponding photovoltaic module, and the other ends are both connected to the main switch.
  • the method includes: closing one or more of the plurality of branch switches to connect the corresponding photovoltaic components to the backflow buffer circuit; after closing one or more of the plurality of branch switches Closing the main switch, so that the reverse sink current generated by the reverse rectification of the DC/AC converter passes through the DC input side of the DC/AC converter and the reverse sink buffer circuit to the access point. and detecting a defective photovoltaic module according to the electroluminescence effect of the photovoltaic module connected to the back-feed buffering circuit under the action of the back-feed current.
  • the back-feed slow-start circuit further includes a current-limiting switch and a current-limiting resistor, and the current-limiting switch and the current-limiting resistor are connected in series with the main switch
  • the switches are connected in parallel
  • the closing of the main switch after closing one or more of the plurality of branch switches includes: closing one or more of the plurality of branch switches and then closing the current limiting switch , the main switch is closed after closing the current-limiting switch for a first time, and the current-limiting switch is disconnected after closing the main switch for a second time, wherein the second time is based on the DC/ The bus voltage on the DC input side of the AC converter is determined.
  • the operation of the main switch, the branch switch and the current limiting switch can effectively suppress the sudden change of the reverse current so as to avoid the damage of the inverter caused by the inrush current, and also maintain the energy utilization efficiency.
  • the back-feed slow-start circuit further includes a current-limiting switch and a current-limiting resistor, wherein the current-limiting switch and the current-limiting resistor are connected in parallel with the The main switch is connected in series, and the closing of the main switch after closing one or more of the plurality of branch switches includes: closing one or more of the plurality of branch switches and then closing the main switch switching switch; closing the current limiting switch after the first time has elapsed after closing the main switching switch.
  • the operation of the main switch, the branch switch and the current limiting switch can effectively suppress the sudden change of the reverse current so as to avoid the damage of the inverter caused by the inrush current, and also maintain the energy utilization efficiency.
  • the back-feed slow-start circuit further includes a current-limiting inductor, the current-limiting inductor is connected in series with the main switch, and the multiple branches are closed. Closing the main switch after one or more of the switches includes closing one or more of the plurality of branch switches and closing the main switch after a first time, wherein the first time is based on The inductance value of the current-limiting inductor and the number of photovoltaic modules connected to the back-feed buffering circuit are determined.
  • the magnitude of the reverse sink current is adjusted according to the bus voltage on the DC input side of the DC/AC converter.
  • the magnitude of the reverse sink current can be dynamically adjusted according to the bus voltage.
  • the bus voltage on the DC input side of the DC/AC converter is adjusted to the lowest value before the detection starts and before the detection ends.
  • the main switch is turned off at the end of the detection, and then the branch switch is turned off, so that the photovoltaic module connected to the back-feed buffer circuit is connected to all the The backwash buffer circuit is disconnected.
  • FIG. 1 shows a schematic diagram of a reverse-feed and slow-start circuit of a string-type photovoltaic inverter according to an implementation manner provided by an embodiment of the present application.
  • FIG. 2 shows a schematic diagram of a reverse-feed and slow-start circuit of a string-type photovoltaic inverter according to another implementation manner provided by an embodiment of the present application.
  • FIG. 3 shows a schematic diagram of a back-feed and slow-start circuit of a string-type photovoltaic inverter according to another implementation manner provided by an embodiment of the present application.
  • FIG. 4 shows a schematic diagram of a reverse-feed and slow-start circuit of a string-type photovoltaic inverter according to another implementation manner provided by an embodiment of the present application.
  • FIG. 5 shows a schematic diagram of a string photovoltaic inverter of another implementation manner provided by the embodiment of the present application.
  • the embodiments of the present application provide a back-feed and start-up circuit of a photovoltaic inverter.
  • the back-feed buffer circuit is connected between the DC input side of the DC/AC converter of the photovoltaic inverter and the output side of the solar photovoltaic array.
  • the back-feed slow-start circuit includes: a plurality of branch switches, wherein the solar photovoltaic array includes a plurality of photovoltaic components, the plurality of branch switches are in one-to-one correspondence with the plurality of photovoltaic components, and the plurality of When the branch switches are closed, the corresponding photovoltaic modules are connected to the back-feeding slow-start circuit; the main switch, wherein one end of the plurality of branch switches is connected to the corresponding photovoltaic modules and the other ends are connected to the main switch; wherein , the main switch is closed after the branch switch is closed, so that the reverse-injection current generated by the reverse rectification of the DC/AC converter passes through the DC input side of the DC/AC converter and the reverse-injection buffer
  • the start-up circuit is connected to the photovoltaic module connected to the back-feed buffer start-up circuit.
  • the embodiments of the present application can be used in the following application scenarios, such as a photovoltaic power generation system, etc., where it is necessary to detect photovoltaic panels or solar photovoltaic arrays formed by multiple photovoltaic modules in series and parallel.
  • FIG. 1 shows a schematic diagram of a reverse-feed and slow-start circuit of a string-type photovoltaic inverter according to an implementation manner provided by an embodiment of the present application.
  • the string-type photovoltaic inverter outputs DC power through a string-type solution module composed of multiple photovoltaic modules.
  • the DC voltages output by multiple photovoltaic modules are boosted by their corresponding DC/DC converters and then connected in parallel to the same DC/AC converter, so that the maximum power point tracking can be realized according to the individual situation of each photovoltaic module. Real-time detection of the power generation voltage of individual photovoltaic modules and achieve maximum power output.
  • the DC output port of each photovoltaic module is connected to the DC input side of the corresponding DC/DC converter, so that the DC power output by each photovoltaic module is boosted by the DC/DC converter, that is, DC/DC
  • the DC voltage at the DC input side of the converter is smaller than the DC voltage at the DC output side of the DC/DC converter.
  • the assembly 151 of the string solution includes a plurality of photovoltaic assemblies numbered 1 to N, including a first photovoltaic assembly 100 , a second photovoltaic assembly 101 and an Nth photovoltaic assembly 102 .
  • a positive integer N is used to represent the total number of photovoltaic modules in the string solution module 151.
  • the DC output port of each PV module has a positive terminal and a negative terminal.
  • the positive and negative terminals of the DC output port of the first photovoltaic module 100 are PV1+ and PV1-, respectively
  • the positive and negative terminals of the DC output port of the second photovoltaic module 101 are PV2+ and PV2-, respectively
  • the The positive and negative terminals of the DC output port are PVN+ and PVN-, respectively.
  • the DC output port of each photovoltaic module is connected to the DC input side of the corresponding DC/DC converter.
  • the positive terminal PV1+ and the negative terminal PV1- of the DC output port of the first photovoltaic module 100 are respectively connected to the positive terminal and the negative terminal of the DC input side of the DC/DC converter 110;
  • the positive terminal PV2+ of the DC output port of the second photovoltaic module 101 and the negative terminal PV2- are respectively connected to the positive terminal and the negative terminal of the DC input side of the DC/DC converter 111;
  • the positive terminal PVN+ and the negative terminal PVN- of the DC output port of the Nth photovoltaic module 102 are respectively connected to the DC/DC converter positive terminal and negative terminal of the DC input side of the device 112 .
  • the DC/DC converter part 152 of the photovoltaic inverter is composed together with a plurality of DC/DC converters corresponding to the plurality of photovoltaic modules in the string solution module 151 one-to-one. It should be understood that the DC power output by the string solution component 151 is boosted by the DC/DC converter part 152 , and then converted into AC power by the DC/AC converter 120 and then transmitted to the AC outlet terminal 130 . Each of the N photovoltaic modules has a corresponding DC/DC converter for boost processing in order to achieve maximum power point tracking. For this reason, when the string solution module 151 includes N photovoltaic modules to be detected, the DC/DC converter part 152 also has N DC/DC converters correspondingly.
  • the positive terminals of the DC output terminals of the N DC/DC converters are all connected to the positive terminals of the DC input side of the DC/AC converter 120, and the negative terminals of the DC output terminals of the N DC/DC converters are all connected to the DC/AC The negative terminal of the DC input side of the converter 120 .
  • a DC bus Between the DC/DC converter portion 152 of the photovoltaic inverter and the DC/AC converter 120 is a DC bus (not shown), and the positive DC bus connects the positive terminal of the DC input side of the DC/AC converter 120,
  • the negative DC bus is connected to the negative terminal of the DC input side of the DC/AC converter 120 .
  • the positive DC bus voltage is identified by BUS+
  • the negative DC bus voltage is identified by BUS-.
  • the DC/AC converter 120 takes a three-phase inverter as an example, and the output three-phase voltages are Va, Vb, and Vc, respectively.
  • the AC outlet terminal 130 is used as an external output interface, which can directly output the electric energy to the load or return the electric energy to the power grid.
  • the backfeed buffer circuit 153 is arranged between the DC output terminal of the string scheme component 151 and the DC input side of the DC/AC converter 120 . Because the DC/DC converter part 152 is also arranged between the DC output terminal of the string scheme component 151 and the DC input side of the DC/AC converter 120, the back-feed buffer circuit 153 and the DC/DC converter part 152 As a whole, it is an alternative, that is, when photovoltaic module detection is required, the DC/DC converter part 152 can be shielded by a bypass switch, so that the DC/AC converter 120 is reverse rectified and the DC/DC converter 120 is reversely rectified.
  • the back-feed slow-up circuit 153 includes a plurality of switches, which are respectively numbered K1, K2 and KN.
  • the string solution component 151 includes N photovoltaic components to be detected, there are N switches and N photovoltaic components in one-to-one correspondence.
  • Each switch has one end connected to the positive terminal of the DC output terminal of the corresponding photovoltaic module.
  • the switch K1 is connected to the positive terminal PV1+ of the DC output port of the first photovoltaic module 100 ; the switch K2 is connected to the positive terminal PV2+ of the DC output port of the second photovoltaic module 101 ; the switch KN is connected to the positive terminal of the DC output port of the Nth photovoltaic module 102 PVN+.
  • the other end of each switch is connected in parallel, that is, each of the N switches K1, K2...KN has one end connected to the positive terminal of the DC output terminals of the N photovoltaic modules, and the other end is connected to the same junction.
  • the back-feed slow-up circuit 153 further includes a current detector 140 for detecting the magnitude of the DC current flowing through the back-feed slow-up circuit 153 .
  • the N switches K1 , K2 . . . KN are connected to the same junction point and then connected in series with the current detector 140 and other devices to form the main loop of the back-feed buffer circuit 153 .
  • all or part of the photovoltaic modules in the string solution module 151 can receive the reverse current through the reverse sink circuit 153, that is, The combination and quantity of PV modules participating in the inspection can be flexibly configured.
  • the current flowing through the current detector 140 is transmitted to the photovoltaic module to be detected through the switch in the closed state after passing through other devices of the back-feed buffer circuit 153, that is to say, one or more corresponding switches are in the closed state.
  • the photovoltaic module is incorporated into the main loop of the backfeed buffer circuit 153 and shunts the current flowing through the current detector 140 .
  • the backfeed slow-up circuit 153 further includes a main switch Kc, a current-limiting inductor Ls, a current-limiting resistor Rs, and a current-limiting switch Ks.
  • the current limiting resistor Rs and the current limiting switch Ks are connected in series, and then connected in parallel with the main switch Kc to form a switchable loop structure, and then connected with the junction of the N switches K1, K2...KN, the current limiting inductor Ls and The current detectors 140 are connected in series.
  • the loop of the current limiting resistor Rs and the current limiting switch Ks can be selectively bypassed through the closing and opening operations of the main switch Kc.
  • the DC/AC converter 120 can work in the state of reverse rectification, that is, the three-phase alternating current at the AC output side of the DC/AC converter 120 is rectified and converted into DC/AC conversion DC bus voltage Vbus at the DC input side of the converter 120 .
  • the DC bus voltage Vbus represents the voltage difference between the positive DC bus and the negative DC bus.
  • the switch K1 corresponding to the first photovoltaic module 100 is closed for a period of time, and then the current limiting switch Ks is closed. After the current limiting switch Ks is closed for a period of time t1, the main switch is closed again. Kc, after the main switch Kc is closed for a period of time t2, the current-limiting switch Ks is turned off, so that the reverse current passes through the current detector 140, the current-limiting inductor Ls, the main switch Kc, and the switch K1 and then transmitted to the first The photovoltaic module 100 realizes detection based on the electroluminescence effect.
  • the main switch Kc When the detection ends, the main switch Kc is first turned off, and after the main switch Kc is turned off for a period of time t3, the switch K1 is turned off. Assuming that there are multiple photovoltaic modules to be detected, for example, the first photovoltaic module 100, the second photovoltaic module 101 and the Nth photovoltaic module 102 all need to be detected, then the corresponding switches K1, K2 and KN are closed first, and then disconnected after the detection is completed. Switches K1, K2 and KN. In this way, according to the combination and quantity of the photovoltaic modules to be detected, the switches corresponding to the photovoltaic modules to be detected among the N switches K1, K2...
  • the photovoltaic modules that need to be tested also ensure the safety of operation in a high-voltage environment.
  • these switches are turned off at the end, that is, when the back-feed slow-start circuit is cut out, the main switch is turned off first, and then the switches corresponding to the photovoltaic modules are turned off, which is beneficial to protect the equipment.
  • this setting can make the reverse current pass through the current-limiting switch Ks and the current-limiting resistor Rs in series
  • the loop formed by connecting the loop effectively suppresses the sudden increase of the current through the loop connected in series by the current limiting resistor Rs and the current limiting inductor Ls, thereby reducing the damage of the inrush current to the inverter.
  • the current-limiting switch Ks is turned off after the main switch Kc is closed for a period of time t2, and the time t2 is related to the DC bus voltage Vbus, that is, it is adjusted and maintained before the current-limiting switch Ks is turned off according to the magnitude of the DC bus voltage Vbus Keep the duration of the main switch Kc closed, so as to effectively avoid the damage to the inverter caused by the inrush current generated at the moment of the switch.
  • the role of the current limiting inductor Ls is to suppress a sudden increase in current.
  • the magnitude of the reverse current is mainly determined by the DC bus voltage Vbus.
  • the DC bus voltage Vbus can be adjusted to the lowest value before the detection starts and before the detection is completed, thereby further reducing the impact of the inrush current.
  • the reverse current may also be called reverse sink current, which refers to the current applied to the photovoltaic module after reverse rectification by the DC/AC converter 120 in order to detect the photovoltaic module.
  • reverse sink current refers to the current applied to the photovoltaic module after reverse rectification by the DC/AC converter 120 in order to detect the photovoltaic module.
  • the DC/DC converter of the DC/DC converter section 152 employs a unidirectional boost converter, ie, is not suitable for Reverse transmission from DC output to DC input.
  • an external bypass switch (not shown) is also included to bypass the unidirectional DC/DC converter.
  • a filter may also be included between the DC/AC converter 120 and the AC outlet 130 .
  • the filter can be used to suppress the switching high-frequency harmonics caused by a specific control method, or it can be a grid-connected filter, or it can be an adjustable filter with adjustable parameters to cope with changing output frequency and equivalent impedance.
  • FIG. 2 shows a schematic diagram of a reverse-feed and slow-start circuit of a string-type photovoltaic inverter according to another implementation manner provided by an embodiment of the present application.
  • the string-type photovoltaic inverter outputs DC power through a string-type solution module composed of multiple photovoltaic modules.
  • the DC voltages output by multiple photovoltaic modules are boosted by their corresponding DC/DC converters and then connected in parallel to the same DC/AC converter, so that the maximum power point tracking can be realized according to the individual situation of each photovoltaic module. Real-time detection of the power generation voltage of individual photovoltaic modules and achieve maximum power output.
  • the DC output port of each photovoltaic module is connected to the DC input side of the corresponding DC/DC converter, so that the DC power output by each photovoltaic module is boosted by the DC/DC converter, that is, DC/DC
  • the DC voltage at the DC input side of the converter is smaller than the DC voltage at the DC output side of the DC/DC converter.
  • the string solution module 251 includes a plurality of photovoltaic modules numbered 1 to N, including a first photovoltaic module 200 , a second photovoltaic module 201 and an Nth photovoltaic module 202 .
  • a positive integer N is used to represent the total number of photovoltaic modules in the string solution module 251 .
  • the DC output port of each PV module has a positive terminal and a negative terminal.
  • the positive and negative terminals of the DC output port of the first photovoltaic module 200 are PV1+ and PV1-, respectively
  • the positive and negative terminals of the DC output port of the second photovoltaic module 201 are PV2+ and PV2-, respectively
  • the The positive and negative terminals of the DC output port are PVN+ and PVN-, respectively.
  • the DC output port of each photovoltaic module is connected to the DC input side of the corresponding DC/DC converter.
  • the positive terminal PV1+ and the negative terminal PV1- of the DC output port of the first photovoltaic module 200 are respectively connected to the positive terminal and the negative terminal of the DC input side of the DC/DC converter 210;
  • the positive terminal PV2+ of the DC output port of the second photovoltaic module 201 and the negative terminal PV2- are respectively connected to the positive terminal and the negative terminal of the DC input side of the DC/DC converter 211;
  • the positive terminal PVN+ and the negative terminal PVN- of the DC output port of the Nth photovoltaic module 202 are respectively connected to the DC/DC converter positive terminal and negative terminal of the DC input side of the device 212 .
  • a DC/DC converter part 252 of the photovoltaic inverter is composed together with a plurality of DC/DC converters corresponding to the plurality of photovoltaic modules in the string solution module 251 one-to-one. It should be understood that the DC power output by the string solution component 251 is boosted by the DC/DC converter part 252 , and then converted into AC power by the DC/AC converter 220 and then transmitted to the AC outlet terminal 230 .
  • Each of the N photovoltaic modules has a corresponding DC/DC converter for boost processing in order to achieve maximum power point tracking. For this reason, when the string solution component 251 includes N photovoltaic components to be detected, the DC/DC converter part 252 also has N DC/DC converters correspondingly.
  • the positive terminals of the DC output terminals of the N DC/DC converters are all connected to the positive terminals of the DC input side of the DC/AC converter 220, and the negative terminals of the DC output terminals of the N DC/DC converters are all connected to the DC/AC The negative terminal of the DC input side of the converter 220 .
  • a DC bus Between the DC/DC converter portion 252 of the photovoltaic inverter and the DC/AC converter 220 is a DC bus (not shown), and the positive DC bus connects the positive terminal of the DC input side of the DC/AC converter 220, The negative DC bus is connected to the negative terminal of the DC input side of the DC/AC converter 220 .
  • the positive DC bus voltage is identified by BUS+
  • the negative DC bus voltage is identified by BUS-.
  • the DC/AC converter 220 takes a three-phase inverter as an example, and the output three-phase voltages are Va, Vb, and Vc, respectively.
  • the AC outlet terminal 230 is used as an external output interface, which can directly output the electric energy to the load or return the electric energy to the power grid.
  • the backfeed buffer circuit 253 is arranged between the DC output terminal of the string scheme component 251 and the DC input side of the DC/AC converter 220 . Because the DC/DC converter part 252 is also arranged between the DC output terminal of the string scheme component 251 and the DC input side of the DC/AC converter 220, the back-feed buffer circuit 253 and the DC/DC converter part 252 It is an alternative as a whole, that is to say, when photovoltaic module detection is required, the DC/DC converter part 252 can be shielded by a bypass switch, so that the DC/AC converter 220 is reverse rectified and the DC/DC converter 220 is reversely rectified.
  • the back-feed slow-up circuit 253 includes a plurality of switches, which are respectively numbered K1, K2 and KN.
  • the string solution component 251 includes N photovoltaic components to be detected, there are N switches and N photovoltaic components in one-to-one correspondence.
  • Each switch has one end connected to the positive terminal of the DC output terminal of the corresponding photovoltaic module.
  • the switch K1 is connected to the positive terminal PV1+ of the DC output port of the first photovoltaic module 200; the switch K2 is connected to the positive terminal PV2+ of the DC output port of the second photovoltaic module 201; the switch KN is connected to the positive terminal of the DC output port of the Nth photovoltaic module 202 PVN+.
  • the other end of each switch is connected in parallel, that is, each of the N switches K1, K2...KN has one end connected to the positive terminal of the DC output terminals of the N photovoltaic modules, and the other end is connected to the same junction.
  • the back-feed slow-up circuit 253 further includes a current detector 240 for detecting the magnitude of the DC current flowing through the back-feed slow-up circuit 253 .
  • the N switches K1 , K2 . . . KN are connected to the same junction point, they are connected in series with the current detector 240 and other devices to form the main loop of the back-feed buffer circuit 253 .
  • all or part of the photovoltaic modules in the string solution module 251 can receive the reverse sink current through the reverse sink buffer circuit 253, that is, The combination and quantity of PV modules participating in the inspection can be flexibly configured.
  • the current flowing through the current detector 240 is transmitted to the photovoltaic module to be detected through the switch in the closed state after passing through other devices of the back-feed buffer circuit 253, that is, one or more corresponding switches are in the closed state.
  • the photovoltaic module is incorporated into the main loop of the backfeed buffer circuit 253 and shunts the current flowing through the current detector 240 .
  • the backfeed slow-up circuit 253 further includes a main switch Kc, a current-limiting resistor Rs, and a current-limiting switch Ks.
  • the current limiting resistor Rs and the current limiting switch Ks are connected in parallel, and then connected in series with the main switch Kc to form an adjustable loop structure, and then connected in series with the junctions of the N switches K1, K2...KN and the current detector 240 connect.
  • the current limiting resistor Rs can be selectively incorporated into the main loop.
  • the DC/AC converter 120 can work in the state of reverse rectification, that is, the three-phase alternating current at the AC output side of the DC/AC converter 220 is rectified and converted into DC/AC conversion DC bus voltage Vbus at the DC input side of the converter 220 .
  • the DC bus voltage Vbus represents the voltage difference between the positive DC bus and the negative DC bus.
  • the switch K1 corresponding to the first photovoltaic module 200 is closed for a period of time, then the main switch Kc is closed, and after the main switch Kc is closed for a period of time t1, the current limiting switch is closed again Ks, so that the reverse current passes through the current detector 140, the current limiting switch Ks, the main switch Kc, and the switch K1 and then is transmitted to the first photovoltaic module 200 to realize detection based on the electroluminescence effect.
  • the main switch Kc is first turned off, and after the main switch Kc is turned off for a period of time, the switch K1 is turned off.
  • the switches K1, K2 and KN are first closed, and then the detection is completed and finally disconnected Switches K1, K2 and KN.
  • the photovoltaic modules that need to be tested also ensure the safety of operation in a high-voltage environment. At the end of the test, these switches are opened at the end, which is beneficial to protect the equipment.
  • the switch corresponding to the photovoltaic module performing the detection is turned off after the main switch Kc is turned off, so that the photovoltaic modules connected to the back-feed slow-up circuit 253 are turned off. It is disconnected from the back-feeding slow-start circuit 253, so as to avoid the damage to the photovoltaic components caused by the surge current and voltage that may be generated at the end of the detection, which is beneficial to protect the equipment.
  • this setting can make the reverse current pass through the current limiting resistor Rs first, thereby suppressing the sudden increase of the current through the current limiting resistor Rs, thereby reducing the impact of the inrush current on the reverse current. damage to the transformer. Then, the current limiting switch Ks is closed again, which is equivalent to bypassing or bypassing the current limiting resistor Rs, so that the reverse current is delivered to the photovoltaic module without passing through the current limiting resistor Rs, which is beneficial to improve the energy utilization efficiency.
  • the main switch Kc when the main switch Kc is closed for a period of time t1, because the current limiting resistor Rs is incorporated into the main circuit at this time, the sudden increase of the reverse current can be effectively avoided, and the effect of slowing the reverse current can be realized.
  • the role of the current limiting inductor Ls is to suppress a sudden increase in current.
  • the magnitude of the reverse current is mainly determined by the DC bus voltage Vbus. Therefore, the DC bus voltage Vbus can be adjusted to the lowest value before the detection starts and before the detection is completed, thereby further reducing the impact of the inrush current.
  • the reverse current may also be referred to as a reverse sink current, which refers to the current applied to the photovoltaic module after reverse rectification by the DC/AC converter 220 in order to detect the photovoltaic module.
  • a reverse sink current refers to the current applied to the photovoltaic module after reverse rectification by the DC/AC converter 220 in order to detect the photovoltaic module.
  • the DC/DC converter of the DC/DC converter section 252 employs a unidirectional boost converter, which is not suitable for Reverse transmission from DC output to DC input.
  • an external bypass switch (not shown) is also included to bypass the unidirectional DC/DC converter.
  • a filter may also be included between the DC/AC converter 220 and the AC outlet 230 .
  • the filter can be used to suppress the switching high-frequency harmonics caused by a specific control method, or it can be a grid-connected filter, or it can be an adjustable filter with adjustable parameters to cope with changing output frequency and equivalent impedance.
  • FIG. 3 shows a schematic diagram of a reverse-feed and slow-start circuit of a string-type photovoltaic inverter according to another implementation manner provided by an embodiment of the present application.
  • the string-type photovoltaic inverter outputs DC power through a string-type solution module composed of multiple photovoltaic modules.
  • the DC voltages output by multiple photovoltaic modules are boosted by their corresponding DC/DC converters and then connected in parallel to the same DC/AC converter, so that the maximum power point tracking can be realized according to the individual situation of each photovoltaic module. Real-time detection of the power generation voltage of individual photovoltaic modules and achieve maximum power output.
  • the DC output port of each photovoltaic module is connected to the DC input side of the corresponding DC/DC converter, so that the DC power output by each photovoltaic module is boosted by the DC/DC converter, that is, DC/DC
  • the DC voltage at the DC input side of the converter is smaller than the DC voltage at the DC output side of the DC/DC converter.
  • the string solution module 351 includes a plurality of photovoltaic modules numbered 1 to N, including a first photovoltaic module 300 , a second photovoltaic module 301 and an Nth photovoltaic module 302 .
  • a positive integer N is used to represent the total number of photovoltaic modules in the string solution module 351 .
  • the DC output port of each PV module has a positive terminal and a negative terminal.
  • the positive and negative terminals of the DC output port of the first photovoltaic module 300 are PV1+ and PV1-, respectively
  • the positive and negative terminals of the DC output port of the second photovoltaic module 301 are PV2+ and PV2-, respectively
  • the The positive and negative terminals of the DC output port are PVN+ and PVN-, respectively.
  • the DC output port of each photovoltaic module is connected to the DC input side of the corresponding DC/DC converter.
  • the positive terminal PV1+ and the negative terminal PV1- of the DC output port of the first photovoltaic module 300 are respectively connected to the positive terminal and the negative terminal of the DC input side of the DC/DC converter 310;
  • the positive terminal PV2+ of the DC output port of the second photovoltaic module 301 and the negative terminal PV2- are respectively connected to the positive terminal and the negative terminal of the DC input side of the DC/DC converter 311;
  • the positive terminal PVN+ and the negative terminal PVN- of the DC output port of the Nth photovoltaic module 302 are respectively connected to the DC/DC converter positive terminal and negative terminal of the DC input side of the device 312 .
  • a DC/DC converter part 352 of the photovoltaic inverter is composed together with a plurality of DC/DC converters corresponding to a plurality of photovoltaic modules in the string solution module 351 one-to-one. It should be understood that the DC power output by the string solution component 351 is boosted by the DC/DC converter part 352 , and then converted into AC power by the DC/AC converter 320 and then transmitted to the AC outlet terminal 330 . Each of the N photovoltaic modules has a corresponding DC/DC converter for boost processing in order to achieve maximum power point tracking. For this reason, when the string solution component 351 includes N photovoltaic components to be detected, the DC/DC converter part 352 also has N DC/DC converters correspondingly.
  • the positive terminals of the DC output terminals of the N DC/DC converters are all connected to the positive terminals of the DC input side of the DC/AC converter 320, and the negative terminals of the DC output terminals of the N DC/DC converters are all connected to the DC/AC The negative terminal of the DC input side of the converter 320 .
  • a DC bus Between the DC/DC converter portion 352 of the photovoltaic inverter and the DC/AC converter 320 is a DC bus (not shown), and the positive DC bus connects the positive terminal of the DC input side of the DC/AC converter 320, The negative DC bus is connected to the negative terminal of the DC input side of the DC/AC converter 320 .
  • the positive DC bus voltage is identified by BUS+
  • the negative DC bus voltage is identified by BUS-.
  • the DC/AC converter 320 takes a three-phase inverter as an example, and the output three-phase voltages are Va, Vb, and Vc, respectively.
  • the AC outlet 330 is used as an external output interface, which can directly output the electric energy to the load or return the electric energy to the power grid.
  • the backfeed buffer circuit 353 is arranged between the DC output terminal of the string scheme component 351 and the DC input side of the DC/AC converter 320 . Because the DC/DC converter part 352 is also arranged between the DC output terminal of the string scheme component 351 and the DC input side of the DC/AC converter 320, the back-feed buffer circuit 353 and the DC/DC converter part 352 As a whole, it is an alternative, that is to say, when the photovoltaic module detection is required, the DC/DC converter part 352 can be shielded by the bypass switch, so that the DC/AC converter 320 is reverse rectified and the DC/DC converter 320 is reversely rectified.
  • the back-feed slow-up circuit 353 includes a plurality of switches, which are respectively numbered K1, K2 and KN.
  • the string solution component 351 includes N photovoltaic components to be detected, there are N switches and N photovoltaic components in one-to-one correspondence.
  • Each switch has one end connected to the positive terminal of the DC output terminal of the corresponding photovoltaic module.
  • the switch K1 is connected to the positive terminal PV1+ of the DC output port of the first photovoltaic module 300; the switch K2 is connected to the positive terminal PV2+ of the DC output port of the second photovoltaic module 301; the switch KN is connected to the positive terminal of the DC output port of the Nth photovoltaic module 302 PVN+.
  • the other end of each switch is connected in parallel, that is, each of the N switches K1, K2...KN has one end connected to the positive terminal of the DC output terminals of the N photovoltaic modules, and the other end is connected to the same junction.
  • the back-feed slow-up circuit 353 further includes a current detector 340 for detecting the magnitude of the DC current flowing through the back-feed slow-up circuit 353 .
  • the N switches K1 , K2 . . . KN are connected to the same junction point, they are connected in series with the current detector 340 and other devices to form the main loop of the back-feed buffer circuit 353 .
  • the N switches K1, K2 . . . KN are connected in series with the current detector 340 and other devices to form the main loop of the back-feed buffer circuit 353 .
  • all or part of the photovoltaic modules in the string solution module 351 can receive the reverse current through the reverse sink circuit 353, that is,
  • the combination and quantity of PV modules participating in the inspection can be flexibly configured.
  • the current flowing through the current detector 340 is transmitted to the photovoltaic module to be detected through the switch in the closed state after passing through other devices of the back-feed buffer circuit 353, that is, one or more of the corresponding switches are in the closed state.
  • the photovoltaic module is incorporated into the main loop of the backfeed buffer circuit 353 and shunts the current flowing through the current detector 340 .
  • the backfeed slow-up circuit 353 further includes a main switch Kc and a current limiting inductor Ls.
  • the current limiting inductor Ls and the main switch Kc are connected in series, and then connected in series with the junction of the N switches K1 , K2 . . . KN and the current detector 340 .
  • the main loop including the current limiting inductance Ls can be set to be in a conducting state or a non-conducting state.
  • the DC/AC converter 320 can work in the state of reverse rectification, that is, the three-phase alternating current at the AC output side of the DC/AC converter 320 is rectified and converted into DC/AC conversion DC bus voltage Vbus at the DC input side of the converter 320 .
  • the DC bus voltage Vbus represents the voltage difference between the positive DC bus and the negative DC bus.
  • the switch K1 corresponding to the first photovoltaic module 300 is closed for a period of time t1, and then the main switch Kc is closed, so that the reverse current passes through the current detector 340, the current limiting inductor Ls, The main switch Kc and the switch K1 are then transmitted to the first photovoltaic module 300 to realize detection based on the electroluminescence effect.
  • the main switch Kc is first turned off, and after the main switch Kc is turned off for a period of time, the switch K1 is turned off.
  • the switches K1, K2 and KN are closed first, and finally disconnected after the detection is completed Switches K1, K2 and KN.
  • the photovoltaic modules that need to be tested also ensure the safety of operation in a high-voltage environment. At the end of the test, these switches are opened at the end, which is beneficial to protect the equipment.
  • the switch corresponding to the photovoltaic module to be detected is turned off after the main switch Kc is turned off, so that the photovoltaic modules connected to the back-feed slow-up circuit 353 are turned off. It is disconnected from the back-feeding slow-start circuit 353, so as to avoid the damage to the photovoltaic components caused by the surge current and voltage that may be generated at the end of the detection, which is beneficial to protect the equipment.
  • the main switch Kc By closing the main switch Kc after the switch K1 is closed for a period of time t1, the main loop is turned on.
  • This setting can suppress the sudden increase of the current through the current limiting inductor Ls, that is to say, the more the inductance value of the current limiting inductor is If it is large, it has a stronger inhibitory effect on the sudden increase of the current.
  • the time t1 is related to the inductance value of the current limiting inductor Ls, and the time t1 is also related to the number of PV modules to be detected. The more PV modules to be detected, the longer the time t1. When there are more PV modules to be tested, more switches in the N switches K1, K2...KN need to be closed for a period of time t1 at the beginning of detection, which means that a longer waiting time is required to meet the increased energy requirements.
  • the magnitude of the reverse current is mainly determined by the DC bus voltage Vbus, so the DC bus voltage Vbus can be adjusted to the lowest value before the detection starts and before the detection is completed, thereby further reducing the impact of the inrush current.
  • the reverse current may also be called reverse sink current, which refers to the current applied to the photovoltaic module after reverse rectification by the DC/AC converter 320 in order to detect the photovoltaic module.
  • reverse sink current refers to the current applied to the photovoltaic module after reverse rectification by the DC/AC converter 320 in order to detect the photovoltaic module.
  • the DC/DC converter of the DC/DC converter section 352 employs a unidirectional boost converter, which is not suitable for Reverse transmission from DC output to DC input.
  • an external bypass switch (not shown) is also included to bypass the unidirectional DC/DC converter.
  • a filter may also be included between the DC/AC converter 320 and the AC outlet 330 .
  • the filter can be used to suppress the switching high-frequency harmonics caused by a specific control method, or it can be a grid-connected filter, or it can be an adjustable filter with adjustable parameters to cope with changing output frequency and equivalent impedance.
  • FIG. 4 shows a schematic diagram of a back-feed and slow-start circuit of a string-type photovoltaic inverter according to another implementation manner provided by an embodiment of the present application.
  • the string-type photovoltaic inverter outputs DC power through a string-type solution module composed of multiple photovoltaic modules.
  • the DC voltages output by multiple photovoltaic modules are boosted by their corresponding DC/DC converters and then connected in parallel to the same DC/AC converter, so that the maximum power point tracking can be realized according to the individual situation of each photovoltaic module. Real-time detection of the power generation voltage of individual photovoltaic modules and achieve maximum power output.
  • the DC output port of each photovoltaic module is connected to the DC input side of the corresponding DC/DC converter, so that the DC power output by each photovoltaic module is boosted by the DC/DC converter, that is, DC/DC
  • the DC voltage at the DC input side of the converter is smaller than the DC voltage at the DC output side of the DC/DC converter.
  • the string solution module 451 includes a plurality of photovoltaic modules numbered 1 to N, including a first photovoltaic module 400 , a second photovoltaic module 401 and an Nth photovoltaic module 402 .
  • a positive integer N is used to represent the total number of photovoltaic modules in the string solution module 451 .
  • the DC output port of each PV module has a positive terminal and a negative terminal.
  • the positive and negative terminals of the DC output port of the first photovoltaic module 400 are PV1+ and PV1-, respectively
  • the positive and negative terminals of the DC output port of the second photovoltaic module 401 are PV2+ and PV2-, respectively
  • the The positive and negative terminals of the DC output port are PVN+ and PVN-, respectively.
  • the DC output port of each photovoltaic module is connected to the DC input side of the corresponding DC/DC converter.
  • the positive terminal PV1+ and the negative terminal PV1- of the DC output port of the first photovoltaic module 400 are respectively connected to the positive terminal and the negative terminal of the DC input side of the DC/DC converter 410;
  • the positive terminal PV2+ of the DC output port of the second photovoltaic module 401 and the negative terminal PV2- are respectively connected to the positive terminal and the negative terminal of the DC input side of the DC/DC converter 411;
  • the positive terminal PVN+ and the negative terminal PVN- of the DC output port of the Nth photovoltaic module 402 are respectively connected to the DC/DC converter positive terminal and negative terminal of the DC input side of the device 412 .
  • a DC/DC converter part 452 of the photovoltaic inverter is composed together with a plurality of DC/DC converters corresponding to a plurality of photovoltaic modules in the string solution module 451 one-to-one. It should be understood that the DC power output by the string solution component 451 is boosted by the DC/DC converter part 452, and then converted into AC power by the DC/AC converter 420, and then transmitted to the AC outlet 430. Each of the N photovoltaic modules has a corresponding DC/DC converter for boost processing in order to achieve maximum power point tracking. For this reason, when the string solution component 451 includes N photovoltaic components to be detected, the DC/DC converter part 452 also has N DC/DC converters correspondingly.
  • the positive terminals of the DC output terminals of the N DC/DC converters are all connected to the positive terminals of the DC input side of the DC/AC converter 420, and the negative terminals of the DC output terminals of the N DC/DC converters are all connected to the DC/AC The negative terminal of the DC input side of the converter 420 .
  • a DC bus Between the DC/DC converter portion 452 of the photovoltaic inverter and the DC/AC converter 420 is a DC bus (not shown), and the positive DC bus connects the positive terminal of the DC input side of the DC/AC converter 420, The negative DC bus is connected to the negative terminal of the DC input side of the DC/AC converter 420 .
  • the positive DC bus voltage is identified by BUS+
  • the negative DC bus voltage is identified by BUS-.
  • the DC/AC converter 420 takes a three-phase inverter as an example, and the output three-phase voltages are Va, Vb, and Vc, respectively.
  • the AC outlet terminal 430 is used as an external output interface, which can directly output the electric energy to the load or return the electric energy to the power grid.
  • the backfeed buffer circuit 453 is arranged between the DC output terminal of the string scheme component 451 and the DC input side of the DC/AC converter 420 . Because the DC/DC converter part 452 is also arranged between the DC output terminal of the string scheme component 451 and the DC input side of the DC/AC converter 420, the back-feed buffer circuit 453 and the DC/DC converter part 452 It is an alternative as a whole, that is to say, when PV module detection is required, the DC/DC converter part 452 can be shielded by a bypass switch, so that the DC/AC converter 420 is reverse rectified and the DC/DC converter 420 is reversely rectified.
  • the back-feeding slow-up circuit 453 includes a plurality of switches, which are respectively numbered K1, K2 and KN.
  • the string solution component 451 includes N photovoltaic components to be detected, there are N switches and N photovoltaic components in one-to-one correspondence.
  • Each switch has one end connected to the positive terminal of the DC output terminal of the corresponding photovoltaic module.
  • the switch K1 is connected to the positive terminal PV1+ of the DC output port of the first photovoltaic module 400; the switch K2 is connected to the positive terminal PV2+ of the DC output port of the second photovoltaic module 401; the switch KN is connected to the positive terminal of the DC output port of the Nth photovoltaic module 402 PVN+.
  • the other end of each switch is connected in parallel, that is, each of the N switches K1, K2...KN has one end connected to the positive terminal of the DC output terminals of the N photovoltaic modules, and the other end is connected to the same junction.
  • the back-feed slow-up circuit 453 further includes a current detector 440 for detecting the magnitude of the DC current flowing through the back-feed slow-up circuit 453 .
  • the N switches K1 , K2 . . . KN are connected to the same junction point and then connected in series with the current detector 440 and other devices to form the main loop of the back-feed buffer circuit 453 .
  • all or part of the photovoltaic modules in the string solution module 451 can receive the reverse current through the reverse sink circuit 453, that is, The combination and quantity of PV modules participating in the inspection can be flexibly configured.
  • the current flowing through the current detector 440 is transmitted to the photovoltaic module to be detected through the switch in the closed state after passing through other devices of the back-feed buffer circuit 453, that is to say, one or more of the corresponding switches are in the closed state.
  • the photovoltaic module is incorporated into the main loop of the back-feed buffer circuit 453 and shunts the current flowing through the current detector 440 .
  • the back-feed buffer circuit 453 further includes a main switch Kc and a step-down conversion circuit 454 .
  • the buck converter circuit 454 may also be referred to as a buck converter (Buck Converter) or a Buck circuit.
  • the step-down conversion circuit 454 includes a diode Db, an inductor Lb and a switch Qb. The inductor Lb and the switch Qb are connected in series, and then connected in series with the main switch Kc, and then connected in series with the junction of the N switches K1 , K2 . . . KN and the current detector 440 .
  • the cathode of the diode Db is connected between the inductor Lb and the switch Qb, and the anode is connected to the negative DC bus, that is, the negative terminal of the DC input side of the DC/AC converter 420 .
  • PWM Pulse Width Modulation
  • the DC/AC converter 420 can work in the state of reverse rectification, that is, the three-phase alternating current at the AC output side of the DC/AC converter 420 is rectified and converted into DC/AC conversion DC bus voltage Vbus at the DC input side of the converter 420 .
  • the DC bus voltage Vbus represents the voltage difference between the positive DC bus and the negative DC bus.
  • the switch K1 corresponding to the first photovoltaic module 400 is closed for a period of time t1, and then the main switch Kc is closed, and after the main switch Kc is closed for a period of time t1, the step-down
  • the switch Qb of the conversion circuit 454 sends a PWM control signal to keep the switch Qb closed so that the voltage on the photovoltaic module to be detected increases slowly, so that the reverse current passes through the current detector 440, the main switch Kc, and the step-down conversion circuit.
  • the switch Qb, the inductor Lb, and the switch K1 of 454 are then transmitted to the first photovoltaic module 400 to realize detection based on the electroluminescence effect.
  • the main switch Kc When the detection ends, the main switch Kc is first turned off, and after the main switch Kc is turned off for a period of time, the switch K1 and the switch Qb of the step-down conversion circuit 454 are turned off. Assuming that there are multiple photovoltaic modules to be detected, for example, the first photovoltaic module 400, the second photovoltaic module 401 and the Nth photovoltaic module 402 all need to be detected, then the corresponding switches K1, K2 and KN are closed first, and finally disconnected after the detection is completed Switches K1, K2 and KN. In this way, according to the combination and quantity of the photovoltaic modules to be detected, the switches corresponding to the photovoltaic modules to be detected among the N switches K1, K2...
  • the photovoltaic modules that need to be tested also ensure the safety of operation in a high-voltage environment. At the end of the test, these switches are opened at the end, which is beneficial to protect the equipment. That is to say, when the detection is over and the back-feed slow-up circuit 453 is switched off, the switch corresponding to the photovoltaic module that is being detected is turned off after the main switch Kc is turned off, so that the photovoltaic modules connected to the back-feed slow-up circuit 453 are turned off. It is disconnected from the back-feeding slow-start circuit 453, so as to avoid the damage to the photovoltaic components caused by the surge current and voltage that may be generated at the end of the detection, which is beneficial to protect the equipment.
  • the reverse current may also be referred to as a reverse sink current, which refers to the current applied to the photovoltaic module after reverse rectification by the DC/AC converter 420 in order to detect the photovoltaic module.
  • the reverse-feed slow-start circuit 453 by operating the reverse-feed slow-start circuit 453, the sudden change of the reverse current can be effectively suppressed when the photovoltaic module is detected, so as to avoid the damage of the inverter caused by the inrush current, and at the same time, the energy utilization efficiency can be effectively maintained.
  • the DC/DC converter of the DC/DC converter section 452 employs a unidirectional boost converter, which is not suitable for voltage and current from DC/DC converters. Reverse transmission from DC output to DC input.
  • an external bypass switch (not shown) is also included to bypass the unidirectional DC/DC converter.
  • a filter may also be included between the DC/AC converter 420 and the AC outlet 430 .
  • the filter can be used to suppress the switching high-frequency harmonics caused by a specific control method, or it can be a grid-connected filter, or it can be an adjustable filter with adjustable parameters to cope with changing output frequency and equivalent impedance.
  • the plurality of switches K1 , K2 . . . KN corresponding to the plurality of photovoltaic modules one-to-one may be mechanical switches such as relays, contactors, etc., or may be electronic Switches switching transistors such as IGBTs, MOSFETs, etc.
  • FIG. 5 shows a schematic diagram of a string photovoltaic inverter of another implementation manner provided by the embodiment of the present application.
  • the string-type photovoltaic inverter outputs DC power through a string-type solution component 501 composed of a plurality of photovoltaic modules.
  • the DC voltages output by the multiple photovoltaic modules are boosted by their corresponding DC/DC converters and then connected in parallel to the same DC/AC converter 512, so that the maximum power point tracking can be realized according to the individual situation of each photovoltaic module. That is, the power generation voltage of individual photovoltaic modules is detected in real time and the maximum power output is achieved.
  • each photovoltaic module is connected to the DC input side of the corresponding DC/DC converter, so that the DC power output by each photovoltaic module is boosted by the DC/DC converter, that is, DC/DC
  • the DC voltage at the DC input side of the converter is smaller than the DC voltage at the DC output side of the DC/DC converter.
  • a plurality of DC/DC converters in a one-to-one correspondence with a plurality of photovoltaic modules in the string solution module 501 together constitute a DC/DC converter part 511 of the photovoltaic inverter.
  • the DC/DC converter of the DC/DC converter part 511 adopts a bidirectional transformer, that is, it can be used for reverse transmission from the DC output terminal to the DC input terminal.
  • the DC/DC converter part 511 and the DC/AC converter 512 together constitute the reverse rectifier 502 of the photovoltaic inverter.
  • the reverse rectifier 502 for example, by applying PWM pulsed control to the DC/DC converter of the DC/DC converter section 511, it is possible to apply the reverse rectified voltage to the photovoltaic module slowly increasing.
  • a filter may also be included between the DC/AC converter 512 and the AC outlet 503 .
  • the filter can be used to suppress the switching high-frequency harmonics caused by a specific control method, or it can be a grid-connected filter, or it can be an adjustable filter with adjustable parameters to cope with changing output frequency and equivalent impedance.
  • a string-type solution component composed of a plurality of photovoltaic components may be a solar photovoltaic array.
  • the DC/DC converter and the DC/AC converter can be integrated in one device or divided into multiple devices.
  • This application does not limit the specific physical forms of the DC/DC converter and the DC/AC converter, that is, the inverter may be composed of a DC/DC converter plus a DC/AC converter, or only a DC/AC converter, DC/DC converter not included.
  • the photovoltaic inverter consists of a DC/DC converter plus a DC/AC converter.
  • the photovoltaic inverter includes only DC/AC converters.
  • the specific embodiments provided herein may be implemented in any one or combination of hardware, software, firmware or solid state logic circuits, and may be implemented in conjunction with signal processing, control and/or special purpose circuits.
  • the apparatus or apparatus provided by the specific embodiments of the present application may include one or more processors (eg, microprocessor, controller, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA) ), etc.), these processors process various computer-executable instructions to control the operation of a device or apparatus.
  • the device or apparatus provided by the specific embodiments of the present application may include a system bus or a data transmission system that couples various components together.
  • a system bus may include any one or a combination of different bus structures, such as a memory bus or memory controller, a peripheral bus, a universal serial bus, and/or processing utilizing any of a variety of bus architectures device or local bus.
  • the equipment or apparatus provided by the specific embodiments of the present application may be provided independently, may also be a part of a system, or may be a part of other equipment or apparatus.
  • Embodiments provided herein may include or be combined with computer-readable storage media, such as one or more storage devices capable of providing non-transitory data storage.
  • the computer-readable storage medium/storage device may be configured to hold data, programmers and/or instructions that, when executed by the processors of the apparatuses or apparatuses provided by the specific embodiments of the present application, cause these apparatuses Or the device realizes the relevant operation.
  • Computer-readable storage media/storage devices may include one or more of the following characteristics: volatile, non-volatile, dynamic, static, read/write, read-only, random access, sequential access, location addressability, File addressability and content addressability.
  • the computer-readable storage medium/storage device may be integrated into the device or apparatus provided by the specific embodiments of the present application or belong to a public system.
  • Computer readable storage media/storage devices may include optical storage devices, semiconductor storage devices and/or magnetic storage devices, etc., and may also include random access memory (RAM), flash memory, read only memory (ROM), erasable and programmable Read Only Memory (EPROM), Electrically Erasable Programmable Read Only Memory (EEPROM), Registers, Hard Disk, Removable Disk, Recordable and/or Rewritable Compact Disc (CD), Digital Versatile Disc (DVD), Mass storage media device or any other form of suitable storage media.
  • RAM random access memory
  • ROM read only memory
  • EPROM erasable and programmable Read Only Memory
  • EEPROM Electrically Erasable Programmable Read Only Memory
  • CD Compact Disc
  • DVD Digital Versatile Disc
  • Mass storage media device or any other form of suitable storage media.

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Abstract

一种光伏逆变器的反灌缓起电路（153）。所述反灌缓起电路（153）包括：多个支路开关（K1、K2、……KN），其中，所述太阳能光伏阵列包括多个光伏组件（100、101、……102），所述多个支路开关（K1、K2、……KN）与所述多个光伏组件（100、101、……102）一一对应，所述多个支路开关（K1、K2、……KN）闭合时对应的光伏组件（100、101、……102）接入所述反灌缓起电路；主切换开关（Kc），其中，所述多个支路开关（K1、K2、……KN）的一端连接对应的光伏组件（100、101、……102），另一端均连接所述主切换开关（Kc）；其中，所述主切换开关（Kc）在所述支路开关（K1、K2、……KN）闭合之后闭合。

Description

组串式光伏逆变器反灌缓起电路 技术领域
本申请涉及电力电子技术，具体涉及组串式光伏逆变器反灌缓起电路。
背景技术
新能源技术比如光伏发电得到了快速发展。光伏发电指的是利用半导体材料的光伏效应将太阳光辐射能转换为电能，例如通过光伏组件在光照下产生直流电。光伏组件是光伏发电系统的核心部分，是将若干个单体太阳能电池以串并联的形式连接后封装成单个组件，用来将太阳能转化成电能，也可以称作光伏电池组件。由于光伏组件质量的优劣直接决定了光伏发电系统的发电性能，且存在器件老化和损耗的因素，因此需要对光伏发电系统中的光伏组件进行检测。
对光伏发电系统中的光伏组件进行检测通常利用电致发光效应(Electroluminescent，EL)。通过对光伏组件或者光伏组件组串施加直流电压从而产生直流反灌电流，因此光伏组件会产生一定强度的红外光，可以利用电荷耦合元件(Charge Coupled Device，CCD)相机或者其他感光器件等成像设备对光伏组件产生的红外光进行捕获成像。其中，有缺陷的光伏组件在成像时呈现出明显的暗斑，从而可以利用这个特性识别有缺陷的光伏组件，进而为光伏组件改进和光伏电站维护提供依据。常见做法是利用整流器将外接电源或移动电源中的交流电转换成直流电，并通过光伏组件上的电源端口将直流电输送至光伏组件，也就是直流反灌电流。
现有技术中，组串式光伏逆变器将若干个光伏组件构成的组串式方案组件直接跟逆变器相连。其中，组串式方案组件输出的直流电经过DC/DC变换器进行升压以实现最大功率点跟踪(Maximum Power Point Tracking，MPPT)，也即实时侦测发电电压并追踪最高电压电流值从而实现最大功率输出。经过DC/DC变换器升压后的直流电压再经过DC/AC变换器转换成交流电压后并入电网进行输送。因为每个光伏组件受到的光照和环境等外界因素影响不同，各自输出的功率变化不同，所以需要多路MPPT和多路DC/DC变换器针对每个光伏组件进行功率跟踪。而受限于成本的考量，DC/DC变换器可能采用单向升压变换器，也就是不能进行电压电流的反向传输。为此，向组串式方案组件输送直流反灌电流时，需要对单向的DC/DC变换器通过外部旁路开关进行处理，而由于DC/AC变换器反向整流过来的母线电压较高，在外部旁路开关切换瞬间会在DC/DC变换器的输入侧产生较大的冲击电流，从而给逆变器造成损坏。并且，采用组串式方案组件输出直流电的组串式光伏逆变器需要同时对多个光伏组件进行检测，从而带来设备庞大、操作困难及高压操作下安全性风险等挑战。
发明内容
本申请的目的在于提供一种光伏逆变器的反灌缓起电路。所述反灌缓起电路连接在所述光伏逆变器的DC/AC变换器的直流输入侧和太阳能光伏阵列的输出侧之间。所述反灌缓起电路包括：多个支路开关，其中，所述太阳能光伏阵列包括多个光伏组件，所述多个支 路开关与所述多个光伏组件一一对应，所述多个支路开关闭合时对应的光伏组件接入所述反灌缓起电路；主切换开关，其中，所述多个支路开关的一端连接对应的光伏组件另一端均连接所述主切换开关；其中，所述主切换开关在所述支路开关闭合之后闭合以使得所述DC/AC变换器反向整流产生的反灌电流经过所述DC/AC变换器的直流输入侧和所述反灌缓起电路到所述接入所述反灌缓起电路的光伏组件。如此，通过选择性地控制多个支路开关的闭合和断开，有利于灵活配置参与检测的光伏组件的组合和数量，同时通过所述主切换开关和所述支路开关的操作实现了有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏。
第一方面，本申请实施例提供了一种光伏逆变器的反灌缓起电路。所述反灌缓起电路连接在所述光伏逆变器的DC/AC变换器的直流输入侧和太阳能光伏阵列的输出侧之间。所述反灌缓起电路包括：多个支路开关，其中，所述太阳能光伏阵列包括多个光伏组件，所述多个支路开关与所述多个光伏组件一一对应，所述多个支路开关闭合时对应的光伏组件接入所述反灌缓起电路；主切换开关，其中，所述多个支路开关的一端连接对应的光伏组件另一端均连接所述主切换开关；其中，所述主切换开关在所述支路开关闭合之后闭合以使得所述DC/AC变换器反向整流产生的反灌电流经过所述DC/AC变换器的直流输入侧和所述反灌缓起电路到所述接入所述反灌缓起电路的光伏组件。
第一方面所描述的技术方案，通过选择性地控制多个支路开关的闭合和断开，有利于灵活配置参与检测的光伏组件的组合和数量，同时通过所述主切换开关和所述支路开关的操作实现了有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏。
根据第一方面，在一种可能的实现方式中，所述反灌缓起电路还包括限流开关和限流电阻，其中，所述限流开关和所述限流电阻串联连接后与所述主切换开关并联连接，所述限流开关在所述支路开关闭合之后闭合，所述主切换开关在所述限流开关闭合经过第一时间之后闭合，所述限流开关在所述主切换开关闭合经过第二时间之后断开，所述第二时间根据所述DC/AC变换器的直流输入侧的母线电压确定。
如此，通过所述主切换开关、所述支路开关和所述限流开关的操作实现了有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏，同时也保持了能量利用效率。
根据第一方面，在一种可能的实现方式中，所述反灌缓起电路还包括限流电感，所述限流开关和所述限流电阻串联连接后与所述主切换开关并联连接再与所述限流电感串联连接。
如此，通过限流电感有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏。
根据第一方面，在一种可能的实现方式中，所述反灌缓起电路还包括限流开关和限流电阻，其中，所述限流开关和所述限流电阻并联连接后与所述主切换开关串联连接，所述主切换开关在所述支路开关闭合之后闭合，所述限流开关在所述主切换开关闭合经过第一时间之后闭合。
如此，通过所述主切换开关、所述支路开关和所述限流开关的操作实现了有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏，同时也保持了能量利用效率。
根据第一方面，在一种可能的实现方式中，所述反灌缓起电路还包括限流电感，所述限流电感串联连接于所述主切换开关，所述主切换开关在所述支路开关闭合经过第一时间 之后闭合，所述第一时间根据所述限流电感的电感值和所述接入所述反灌缓起电路的光伏组件的数量确定。
如此，通过限流电感有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏。
根据第一方面，在一种可能的实现方式中，所述反灌缓起电路还包括降压式变换电路，所述降压式变换电路包括电感和开关管，所述电感和所述开关管串联连接后与所述主切换开关串联连接，所述降压式变换电路的开关管在脉冲宽度调制信号控制下保持闭合以使得所述反灌电流经过所述降压式变换电路。
如此，通过降压式变换电路有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏。
根据第一方面，在一种可能的实现方式中，所述反灌电流的大小根据所述DC/AC变换器的直流输入侧的母线电压调节。
如此，实现了根据母线电压动态调节反灌电流大小。
根据第一方面，在一种可能的实现方式中，所述DC/AC变换器的直流输入侧的母线电压在检测开始前和检测结束前调节到最低值。
如此，通过调节母线电压到最低值有效抑制了开关瞬间产生的冲击电流对逆变器造成的损坏。
根据第一方面，在一种可能的实现方式中，所述支路开关在所述主切换开关断开之后断开从而使得所述接入所述反灌缓起电路的光伏组件与所述反灌缓起电路断开连接。
如此，通过在反灌缓起电路切出时先断开主切换开关再断开支路开关，有利于保护设备。
第二方面，本申请实施例提供了一种光伏逆变器，所述光伏逆变器包括多个双向DC/DC变换器，所述多个双向DC/DC变换器连接太阳能光伏阵列的多个光伏组件，所述光伏逆变器通过所述多个双向DC/DC变换器在脉冲宽度调制信号下的脉冲式控制从而将反向整流电压施加到对应的光伏组件。
第二方面所描述的技术方案，通过控制多个双向DC/DC变换器有效抑制反灌电流的突然变化。
第三方面，本申请实施例提供了一种对太阳能光伏阵列进行电致发光检测的方法，所述太阳能光伏阵列包括多个光伏组件，与所述太阳能光伏阵列连接的光伏逆变器包括DC/AC变换器，反灌缓起电路连接在所述光伏逆变器的DC/AC变换器的直流输入侧和所述太阳能光伏阵列的输出侧之间，所述反灌缓起电路包括与所述多个光伏组件一一对应的多个支路开关和主切换开关，所述多个支路开关的一端连接对应的光伏组件另一端均连接所述主切换开关。所述方法包括：闭合所述多个支路开关中的一个或多个以将对应的光伏组件接入所述反灌缓起电路；闭合所述多个支路开关中的一个或多个之后闭合所述主切换开关，以使得所述DC/AC变换器反向整流产生的反灌电流经过所述DC/AC变换器的直流输入侧和所述反灌缓起电路到所述接入所述反灌缓起电路的光伏组件；和根据所述接入所述反灌缓起电路的光伏组件在所述反灌电流作用下的电致发光效应检测出有缺陷的光伏组件。
第三方面所描述的技术方案，通过选择性地控制多个支路开关的闭合和断开，有利于灵活配置参与检测的光伏组件的组合和数量，同时通过所述主切换开关和所述支路开关的操作实现了有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏。
根据第三方面，在一种可能的实现方式中，所述反灌缓起电路还包括限流开关和限流电阻，所述限流开关和所述限流电阻串联连接后与所述主切换开关并联连接，所述闭合所述多个支路开关中的一个或多个之后闭合所述主切换开关包括：闭合所述多个支路开关中的一个或多个之后闭合所述限流开关，闭合所述限流开关经过第一时间之后闭合所述主切换开关，闭合所述主切换开关经过第二时间之后断开所述限流开关，其中，所述第二时间根据所述DC/AC变换器的直流输入侧的母线电压确定。
如此，通过所述主切换开关、所述支路开关和所述限流开关的操作实现了有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏，同时也保持了能量利用效率。
根据第三方面，在一种可能的实现方式中，所述反灌缓起电路还包括限流开关和限流电阻，其中，所述限流开关和所述限流电阻并联连接后与所述主切换开关串联连接，所述闭合所述多个支路开关中的一个或多个之后闭合所述主切换开关包括：闭合所述多个支路开关中的一个或多个之后闭合所述主切换开关；闭合所述主切换开关经过第一时间后闭合所述限流开关。
如此，通过所述主切换开关、所述支路开关和所述限流开关的操作实现了有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏，同时也保持了能量利用效率。
根据第三方面，在一种可能的实现方式中，所述反灌缓起电路还包括限流电感，所述限流电感串联连接于所述主切换开关，所述闭合所述多个支路开关中的一个或多个之后闭合所述主切换开关包括：闭合所述多个支路开关中的一个或多个经过第一时间之后闭合所述主切换开关，其中，所述第一时间根据所述限流电感的电感值和所述接入所述反灌缓起电路的光伏组件的数量确定。
如此，通过限流电感有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏。
根据第三方面，在一种可能的实现方式中，所述反灌电流的大小根据所述DC/AC变换器的直流输入侧的母线电压调节。
如此，实现了根据母线电压动态调节反灌电流大小。
根据第三方面，在一种可能的实现方式中，在检测开始前和检测结束前调节所述DC/AC变换器的直流输入侧的母线电压到最低值。
如此，通过调节母线电压到最低值有效抑制了开关瞬间产生的冲击电流对逆变器造成的损坏。
根据第三方面，在一种可能的实现方式中，检测结束时断开所述主切换开关之后断开所述支路开关从而使得所述接入所述反灌缓起电路的光伏组件与所述反灌缓起电路断开连接。
如此，通过在反灌缓起电路切出时先断开主切换开关再断开支路开关，有利于保护设备。
附图说明
为了说明本申请实施例或背景技术中的技术方案，下面将对本申请实施例或背景技术中所需要使用的附图进行说明。
图1示出了本申请实施例提供的一种实现方式的组串式光伏逆变器反灌缓起电路的原理图。
图2示出了本申请实施例提供的另一种实现方式的组串式光伏逆变器反灌缓起电路的原理图。
图3示出了本申请实施例提供的另一种实现方式的组串式光伏逆变器反灌缓起电路的原理图。
图4示出了本申请实施例提供的另一种实现方式的组串式光伏逆变器反灌缓起电路的原理图。
图5示出了本申请实施例提供的另一种实现方式的组串式光伏逆变器的原理图。
具体实施方式
本申请实施例提供了一种光伏逆变器的反灌缓起电路。所述反灌缓起电路连接在所述光伏逆变器的DC/AC变换器的直流输入侧和太阳能光伏阵列的输出侧之间。所述反灌缓起电路包括：多个支路开关，其中，所述太阳能光伏阵列包括多个光伏组件，所述多个支路开关与所述多个光伏组件一一对应，所述多个支路开关闭合时对应的光伏组件接入所述反灌缓起电路；主切换开关，其中，所述多个支路开关的一端连接对应的光伏组件另一端均连接所述主切换开关；其中，所述主切换开关在所述支路开关闭合之后闭合以使得所述DC/AC变换器反向整流产生的反灌电流经过所述DC/AC变换器的直流输入侧和所述反灌缓起电路到所述接入所述反灌缓起电路的光伏组件。如此，通过选择性地控制多个支路开关的闭合和断开，有利于灵活配置参与检测的光伏组件的组合和数量，同时通过所述主切换开关和所述支路开关的操作实现了有效抑制反灌电流的突然变化从而避免冲击电流造成逆变器损坏。
本申请实施例可用于以下应用场景，光伏发电系统等需要对多个光伏组件串并联形成的光伏面板或者太阳能光伏阵列进行检测的场景。
本申请实施例可以依据具体应用环境进行调整和改进，此处不做具体限定。
为了使本技术领域的人员更好地理解本申请方案，下面将结合本申请实施例中的附图，对本申请的实施例进行描述。
请参阅图1，图1示出了本申请实施例提供的一种实现方式的组串式光伏逆变器反灌缓起电路的原理图。组串式光伏逆变器通过由多个光伏组件构成的组串式方案组件输出直流电。其中，多个光伏组件输出的直流电压经过各自对应的DC/DC变换器升压后并联连接于同一个DC/AC变换器，从而可以针对每一个光伏组件的个别情况实现最大功率点跟踪也即实时侦测个别光伏组件的发电电压并实现最大功率输出。为此，每一个光伏组件的直流电输出端口连接于对应的DC/DC变换器的直流输入侧，使得每个光伏组件各自输出的直流电经过DC/DC变换器升压，也就是说，DC/DC变换器的直流输入侧的直流电压要小于DC/DC变换器的直流输出侧的直流电压。如图1所示，组串式方案组件151包括多个光伏组件编号为1到N，其中有第1光伏组件100、第2光伏组件101和第N光伏组件102。这 里，正整数N用来表示组串式方案组件151中光伏组件的总数。每个光伏组件的直流电输出端口有正极端和负极端。第1光伏组件100的直流输出端口的正极端和负极端分别为PV1+和PV1-，第2光伏组件101的直流输出端口的正极端和负极端分别为PV2+和PV2-，第N光伏组件102的直流输出端口的正极端和负极端分别为PVN+和PVN-。每一个光伏组件的直流电输出端口连接于对应的DC/DC变换器的直流输入侧。第1光伏组件100的直流输出端口正极端PV1+和负极端PV1-分别连接于DC/DC变换器110的直流输入侧的正极端和负极端；第2光伏组件101的直流输出端口的正极端PV2+和负极端PV2-分别连接于DC/DC变换器111的直流输入侧的正极端和负极端；第N光伏组件102的直流输出端口的正极端PVN+和负极端PVN-分别连接于DC/DC变换器112的直流输入侧的正极端和负极端。与组串式方案组件151中的多个光伏组件一一对应的多个DC/DC变换器一起组成光伏逆变器的DC/DC变换器部分152。应当理解的是，组串式方案组件151输出的直流电经过DC/DC变换器部分152升压后，再经过DC/AC变换器120转换成交流电后传输到交流出线端130。N个光伏组件的每一个都有对应的DC/DC变换器用来进行升压处理以便实现最大功率点跟踪。为此，当组串式方案组件151包括N个需要进行检测的光伏组件，DC/DC变换器部分152也相应的有N个DC/DC变换器。N个DC/DC变换器的直流输出端的正极端都连接于DC/AC变换器120的直流输入侧的正极端，而N个DC/DC变换器的直流输出端的负极端都连接于DC/AC变换器120的直流输入侧的负极端。在光伏逆变器的DC/DC变换器部分152和DC/AC变换器120之间是直流母线(未示出)，并且正极直流母线连接DC/AC变换器120的直流输入侧的正极端，负极直流母线连接DC/AC变换器120的直流输入侧的负极端。图1中以BUS+标识正极直流母线电压，和BUS-标识负极直流母线电压。DC/AC变换器120以三相逆变器为例，输出三相电压分别为Va、Vb、Vc。交流出线端130作为对外输出接口，可以将电能直接输出向负载也可能将电能返回电网。
请继续参阅图1，反灌缓起电路153布置在组串式方案组件151的直流输出端和DC/AC变换器120的直流输入侧之间。因为DC/DC变换器部分152也是布置在组串式方案组件151的直流输出端和DC/AC变换器120的直流输入侧之间，所以反灌缓起电路153与DC/DC变换器部分152整体上看是替代式的，也就是说，当需要进行光伏组件检测时，DC/DC变换器部分152可以通过旁路开关而屏蔽掉，这样通过DC/AC变换器120反向整流而在DC/AC变换器120的直流输入侧产生的母线电压会经过反灌缓起电路153的回路而施加在光伏组件上，从而利用电致发光效应生成检测图像。其中，反灌缓起电路153包括多个开关，分别编号为K1、K2一直到KN。这里，当组串式方案组件151包括N个需要进行检测的光伏组件，则有N个开关与N个光伏组件一一对应。每一个开关均有一端连接于对应的光伏组件的直流输出端的正极端。例如，开关K1连接第1光伏组件100的直流输出端口正极端PV1+；开关K2连接第2光伏组件101的直流输出端口的正极端PV2+；开关KN连接第N光伏组件102的直流输出端口的正极端PVN+。每一个开关的另一端并联连接，也就是说，N个开关K1、K2…KN各自有一端与N个光伏组件的直流输出端的正极端连接，而另一端则连接于同一个结合点。反灌缓起电路153还包括电流检测器140用于检测流经反灌缓起电路153的直流电流的大小。N个开关K1、K2…KN在连接于同一个结合点之后再跟电流检测器140和其它器件串联连接而形成反灌缓起电路153的主要回路。如此，通 过选择性地控制N个开关K1、K2…KN的闭合和断开，可以让组串式方案组件151中的全部或者部分光伏组件通过反灌缓起电路153接收反灌电流，也就是可以灵活配置参与检测的光伏组件的组合和数量。另外，流经电流检测器140的电流经过反灌缓起电路153其它器件后再通过处于闭合状态的开关传输到待检测的光伏组件，也就是说，对应的开关处于闭合状态的一个或多个光伏组件并入反灌缓起电路153的主要回路并分流流经电流检测器140的电流。
请继续参阅图1，反灌缓起电路153还包括主切换开关Kc，限流电感Ls，限流电阻Rs，以及限流开关Ks。其中，限流电阻Rs和限流开关Ks串联连接在一起，然后和主切换开关Kc并联连接组成可切换的回路结构，再跟N个开关K1、K2…KN的结合点、限流电感Ls以及电流检测器140串联连接。通过主切换开关Kc的闭合和断开操作，可以选择性地绕过限流电阻Rs和限流开关Ks的回路。当需要输送反向电流到光伏组件，DC/AC变换器120可以工作在反向整流的状态，也就是将DC/AC变换器120的交流输出侧的三相交流电整流后转换成DC/AC变换器120的直流输入侧的直流母线电压Vbus。这里，直流母线电压Vbus表示正极直流母线和负极直流母线之间的压差。在检测开始时，N个开关K1、K2…KN，主切换开关Kc以及限流开关Ks的初始状态均是断开状态，这意味着反灌缓起电路153在光伏逆变器正常工作时处于断路的状态，并不干扰正常工作。假设第1光伏组件100需要进行检测，则与第1光伏组件100对应的开关K1先闭合一段时间，然后再闭合限流开关Ks，等限流开关Ks闭合一段时间t1之后，再闭合主切换开关Kc，等主切换开关Kc闭合一段时间t2之后，再断开限流开关Ks，这样反向电流经过电流检测器140，限流电感Ls，主切换开关Kc，还有开关K1之后传输到第1光伏组件100实现基于电致发光效应的检测。当检测结束时，首先断开主切换开关Kc，等主切换开关Kc断开一段时间t3之后，再断开开关K1。假设有多个光伏组件需要检测，例如第1光伏组件100、第2光伏组件101和第N光伏组件102均需要检测，则首先闭合对应的开关K1、K2和KN，等检测结束后最后断开开关K1、K2和KN。如此，根据要进行检测的光伏组件的组合和数量，首先闭合N个开关K1、K2…KN中与这些要检测的光伏组件对应的开关，同时保持其它开关处于断开状态，从而有利于灵活配置需要检测的光伏组件同时保证了高压环境下操作的安全性。而在检测结束时，则在最后才断开这些开关，也即在反灌缓起电路切出时先断开主切换开关再断开与光伏组件对应的这些开关，从而有利于保护设备。通过先闭合限流开关Ks一段时间t1之后，再闭合主切换开关Kc一段时间t2，然后再断开限流开关Ks，如此设置可以使得反向电流先通过限流开关Ks和限流电阻Rs串联连接组成的回路，从而通过限流电阻Rs和限流电感Ls串联连接的回路有效抑制电流的突然增大，从而减少冲击电流对逆变器的损坏。这里，在闭合限流开关Ks一段时间t1的期间，因为限流电阻Rs此时被并入了主回路，可以有效避免反向电流的突然增大，实现反向电流缓起的效果。然后再闭合主切换开关Kc从而等效于绕过了限流电阻Rs，从而让反向电流不经过限流电阻Rs而输送到光伏组件，从而有利于提高能量利用效率。这里，在闭合主切换开关Kc一段时间t2之后才断开限流开关Ks，而时间t2与直流母线电压Vbus有关，也就是根据直流母线电压Vbus的大小而调节保持在断开限流开关Ks之前保持主切换开关Kc闭合的持续时间的长短，如此可以有效避免开关瞬间产生的冲击电流给逆变器带来的损坏。另外，限流电感Ls的作 用是抑制电流突然增大。而反向电流的大小主要由直流母线电压Vbus来决定，因此在开始检测前和检测结束前，可以将直流母线电压Vbus调节到最低值，从而进一步减少冲击电流的影响。这里，反向电流也可以称作反灌电流，指的是为了检测光伏组件而通过DC/AC变换器120进行反向整流后施加在光伏组件上的电流。如此，通过操作反灌缓起电路153，实现了在检测光伏组件时能够有效抑制反向电流的突然变化从而避免冲击电流造成逆变器损坏，同时又有效保持能量利用效率。
请继续参阅图1，在一些示例性实施例中，DC/DC变换器部分152的DC/DC变换器采用单向升压变换器，也就是不适合用于电压电流从DC/DC变换器的直流输出端到直流输端的反向传输。为此，还包括外部旁路开关(未示出)来对单向的DC/DC变换器进行旁路处理。
请继续参阅图1，在一些示例性实施例中，还可以在DC/AC变换器120和交流出线端130之间包括滤波器(未示出)。滤波器可以用来抑制因为采用特定控制方式而产生的开关高频谐波，或者可以是并网滤波器，或者可以是参数可调的可调式滤波器从而应对变化的输出频率和等效阻抗。
请参阅图2，图2示出了本申请实施例提供的另一种实现方式的组串式光伏逆变器反灌缓起电路的原理图。组串式光伏逆变器通过由多个光伏组件构成的组串式方案组件输出直流电。其中，多个光伏组件输出的直流电压经过各自对应的DC/DC变换器升压后并联连接于同一个DC/AC变换器，从而可以针对每一个光伏组件的个别情况实现最大功率点跟踪也即实时侦测个别光伏组件的发电电压并实现最大功率输出。为此，每一个光伏组件的直流电输出端口连接于对应的DC/DC变换器的直流输入侧，使得每个光伏组件各自输出的直流电经过DC/DC变换器升压，也就是说，DC/DC变换器的直流输入侧的直流电压要小于DC/DC变换器的直流输出侧的直流电压。如图2所示，组串式方案组件251包括多个光伏组件编号为1到N，其中有第1光伏组件200、第2光伏组件201和第N光伏组件202。这里，正整数N用来表示组串式方案组件251中光伏组件的总数。每个光伏组件的直流电输出端口有正极端和负极端。第1光伏组件200的直流输出端口的正极端和负极端分别为PV1+和PV1-，第2光伏组件201的直流输出端口的正极端和负极端分别为PV2+和PV2-，第N光伏组件202的直流输出端口的正极端和负极端分别为PVN+和PVN-。每一个光伏组件的直流电输出端口连接于对应的DC/DC变换器的直流输入侧。第1光伏组件200的直流输出端口正极端PV1+和负极端PV1-分别连接于DC/DC变换器210的直流输入侧的正极端和负极端；第2光伏组件201的直流输出端口的正极端PV2+和负极端PV2-分别连接于DC/DC变换器211的直流输入侧的正极端和负极端；第N光伏组件202的直流输出端口的正极端PVN+和负极端PVN-分别连接于DC/DC变换器212的直流输入侧的正极端和负极端。与组串式方案组件251中的多个光伏组件一一对应的多个DC/DC变换器一起组成光伏逆变器的DC/DC变换器部分252。应当理解的是，组串式方案组件251输出的直流电经过DC/DC变换器部分252升压后，再经过DC/AC变换器220转换成交流电后传输到交流出线端230。N个光伏组件的每一个都有对应的DC/DC变换器用来进行升压处理以便实现最大功率点跟踪。为此，当组串式方案组件251包括N个需要进行检测的光伏组件， DC/DC变换器部分252也相应的有N个DC/DC变换器。N个DC/DC变换器的直流输出端的正极端都连接于DC/AC变换器220的直流输入侧的正极端，而N个DC/DC变换器的直流输出端的负极端都连接于DC/AC变换器220的直流输入侧的负极端。在光伏逆变器的DC/DC变换器部分252和DC/AC变换器220之间是直流母线(未示出)，并且正极直流母线连接DC/AC变换器220的直流输入侧的正极端，负极直流母线连接DC/AC变换器220的直流输入侧的负极端。图2中以BUS+标识正极直流母线电压，和BUS-标识负极直流母线电压。DC/AC变换器220以三相逆变器为例，输出三相电压分别为Va、Vb、Vc。交流出线端230作为对外输出接口，可以将电能直接输出向负载也可能将电能返回电网。
请继续参阅图2，反灌缓起电路253布置在组串式方案组件251的直流输出端和DC/AC变换器220的直流输入侧之间。因为DC/DC变换器部分252也是布置在组串式方案组件251的直流输出端和DC/AC变换器220的直流输入侧之间，所以反灌缓起电路253与DC/DC变换器部分252整体上看是替代式的，也就是说，当需要进行光伏组件检测时，DC/DC变换器部分252可以通过旁路开关而屏蔽掉，这样通过DC/AC变换器220反向整流而在DC/AC变换器220的直流输入侧产生的母线电压会经过反灌缓起电路253的回路而施加在光伏组件上，从而利用电致发光效应生成检测图像。其中，反灌缓起电路253包括多个开关，分别编号为K1、K2一直到KN。这里，当组串式方案组件251包括N个需要进行检测的光伏组件，则有N个开关与N个光伏组件一一对应。每一个开关均有一端连接于对应的光伏组件的直流输出端的正极端。例如，开关K1连接第1光伏组件200的直流输出端口正极端PV1+；开关K2连接第2光伏组件201的直流输出端口的正极端PV2+；开关KN连接第N光伏组件202的直流输出端口的正极端PVN+。每一个开关的另一端并联连接，也就是说，N个开关K1、K2…KN各自有一端与N个光伏组件的直流输出端的正极端连接，而另一端则连接于同一个结合点。反灌缓起电路253还包括电流检测器240用于检测流经反灌缓起电路253的直流电流的大小。N个开关K1、K2…KN在连接于同一个结合点之后再跟电流检测器240和其它器件串联连接而形成反灌缓起电路253的主要回路。如此，通过选择性地控制N个开关K1、K2…KN的闭合和断开，可以让组串式方案组件251中的全部或者部分光伏组件通过反灌缓起电路253接收反灌电流，也就是可以灵活配置参与检测的光伏组件的组合和数量。另外，流经电流检测器240的电流经过反灌缓起电路253其它器件后再通过处于闭合状态的开关传输到待检测的光伏组件，也就是说，对应的开关处于闭合状态的一个或多个光伏组件并入反灌缓起电路253的主要回路并分流流经电流检测器240的电流。
请继续参阅图2，反灌缓起电路253还包括主切换开关Kc，限流电阻Rs，以及限流开关Ks。其中，限流电阻Rs和限流开关Ks并联连接在一起，然后和主切换开关Kc串联连接组成可调整的回路结构，再跟N个开关K1、K2…KN的结合点以及电流检测器240串联连接。通过限流开关Ks的闭合和断开操作，可以选择性地将限流电阻Rs并入主回路。当需要输送反向电流到光伏组件，DC/AC变换器120可以工作在反向整流的状态，也就是将DC/AC变换器220的交流输出侧的三相交流电整流后转换成DC/AC变换器220的直流输入侧的直流母线电压Vbus。这里，直流母线电压Vbus表示正极直流母线和负极直流母线之间的压差。在检测开始时，N个开关K1、K2…KN，主切换开关Kc以及限流开关Ks的 初始状态均是断开状态，这意味着反灌缓起电路253在光伏逆变器正常工作时处于断路的状态，并不干扰正常工作。假设第1光伏组件200需要进行检测，则与第1光伏组件200对应的开关K1先闭合一段时间，然后再闭合主切换开关Kc，等主切换开关Kc闭合一段时间t1之后，再闭合限流开关Ks，这样反向电流经过电流检测器140，限流开关Ks，主切换开关Kc，还有开关K1之后传输到第1光伏组件200实现基于电致发光效应的检测。当检测结束时，首先断开主切换开关Kc，等主切换开关Kc断开一段时间之后，再断开开关K1。假设有多个光伏组件需要检测，例如第1光伏组件200、第2光伏组件201和第N光伏组件202均需要检测，则首先闭合对应的开关K1、K2和KN，等检测结束后最后断开开关K1、K2和KN。如此，根据要进行检测的光伏组件的组合和数量，首先闭合N个开关K1、K2…KN中与这些要检测的光伏组件对应的开关，同时保持其它开关处于断开状态，从而有利于灵活配置需要检测的光伏组件同时保证了高压环境下操作的安全性。而在检测结束时，则在最后才断开这些开关，从而有利于保护设备。也就是说，当检测结束而反灌缓起电路253切出时，与进行检测的光伏组件对应的开关在主切换开关Kc断开之后断开从而使得接入反灌缓起电路253的光伏组件与反灌缓起电路253断开连接，从而避免了检测结束时可能产生的冲击电流电压对光伏组件产生伤害，有利于保护设备。通过先闭合主切换开关Kc一段时间，再闭合限流开关Ks，如此设置可以使得反向电流先通过限流电阻Rs，从而通过限流电阻Rs抑制电流的突然增大，从而减少冲击电流对逆变器的损坏。然后再闭合限流开关Ks从而等效于绕过了或者旁路了限流电阻Rs，从而让反向电流不经过限流电阻Rs而输送到光伏组件，从而有利于提高能量利用效率。这里，在闭合主切换开关Kc一段时间t1的期间，因为限流电阻Rs此时被并入了主回路，可以有效避免反向电流的突然增大，实现反向电流缓起的效果。另外，限流电感Ls的作用是抑制电流突然增大。而反向电流的大小主要由直流母线电压Vbus来决定，因此在开始检测前和检测结束前，可以将直流母线电压Vbus调节到最低值，从而进一步减少冲击电流的影响。这里，反向电流也可以称作反灌电流，指的是为了检测光伏组件而通过DC/AC变换器220进行反向整流后施加在光伏组件上的电流。如此，通过操作反灌缓起电路253，实现了在检测光伏组件时能够有效抑制反向电流的突然变化从而避免冲击电流造成逆变器损坏，同时又有效保持能量利用效率。
请继续参阅图2，在一些示例性实施例中，DC/DC变换器部分252的DC/DC变换器采用单向升压变换器，也就是不适合用于电压电流从DC/DC变换器的直流输出端到直流输端的反向传输。为此，还包括外部旁路开关(未示出)来对单向的DC/DC变换器进行旁路处理。
请继续参阅图2，在一些示例性实施例中，还可以在DC/AC变换器220和交流出线端230之间包括滤波器(未示出)。滤波器可以用来抑制因为采用特定控制方式而产生的开关高频谐波，或者可以是并网滤波器，或者可以是参数可调的可调式滤波器从而应对变化的输出频率和等效阻抗。
请参阅图3，图3示出了本申请实施例提供的另一种实现方式的组串式光伏逆变器反灌缓起电路的原理图。组串式光伏逆变器通过由多个光伏组件构成的组串式方案组件输出 直流电。其中，多个光伏组件输出的直流电压经过各自对应的DC/DC变换器升压后并联连接于同一个DC/AC变换器，从而可以针对每一个光伏组件的个别情况实现最大功率点跟踪也即实时侦测个别光伏组件的发电电压并实现最大功率输出。为此，每一个光伏组件的直流电输出端口连接于对应的DC/DC变换器的直流输入侧，使得每个光伏组件各自输出的直流电经过DC/DC变换器升压，也就是说，DC/DC变换器的直流输入侧的直流电压要小于DC/DC变换器的直流输出侧的直流电压。如图3所示，组串式方案组件351包括多个光伏组件编号为1到N，其中有第1光伏组件300、第2光伏组件301和第N光伏组件302。这里，正整数N用来表示组串式方案组件351中光伏组件的总数。每个光伏组件的直流电输出端口有正极端和负极端。第1光伏组件300的直流输出端口的正极端和负极端分别为PV1+和PV1-，第2光伏组件301的直流输出端口的正极端和负极端分别为PV2+和PV2-，第N光伏组件302的直流输出端口的正极端和负极端分别为PVN+和PVN-。每一个光伏组件的直流电输出端口连接于对应的DC/DC变换器的直流输入侧。第1光伏组件300的直流输出端口正极端PV1+和负极端PV1-分别连接于DC/DC变换器310的直流输入侧的正极端和负极端；第2光伏组件301的直流输出端口的正极端PV2+和负极端PV2-分别连接于DC/DC变换器311的直流输入侧的正极端和负极端；第N光伏组件302的直流输出端口的正极端PVN+和负极端PVN-分别连接于DC/DC变换器312的直流输入侧的正极端和负极端。与组串式方案组件351中的多个光伏组件一一对应的多个DC/DC变换器一起组成光伏逆变器的DC/DC变换器部分352。应当理解的是，组串式方案组件351输出的直流电经过DC/DC变换器部分352升压后，再经过DC/AC变换器320转换成交流电后传输到交流出线端330。N个光伏组件的每一个都有对应的DC/DC变换器用来进行升压处理以便实现最大功率点跟踪。为此，当组串式方案组件351包括N个需要进行检测的光伏组件，DC/DC变换器部分352也相应的有N个DC/DC变换器。N个DC/DC变换器的直流输出端的正极端都连接于DC/AC变换器320的直流输入侧的正极端，而N个DC/DC变换器的直流输出端的负极端都连接于DC/AC变换器320的直流输入侧的负极端。在光伏逆变器的DC/DC变换器部分352和DC/AC变换器320之间是直流母线(未示出)，并且正极直流母线连接DC/AC变换器320的直流输入侧的正极端，负极直流母线连接DC/AC变换器320的直流输入侧的负极端。图3中以BUS+标识正极直流母线电压，和BUS-标识负极直流母线电压。DC/AC变换器320以三相逆变器为例，输出三相电压分别为Va、Vb、Vc。交流出线端330作为对外输出接口，可以将电能直接输出向负载也可能将电能返回电网。
请继续参阅图3，反灌缓起电路353布置在组串式方案组件351的直流输出端和DC/AC变换器320的直流输入侧之间。因为DC/DC变换器部分352也是布置在组串式方案组件351的直流输出端和DC/AC变换器320的直流输入侧之间，所以反灌缓起电路353与DC/DC变换器部分352整体上看是替代式的，也就是说，当需要进行光伏组件检测时，DC/DC变换器部分352可以通过旁路开关而屏蔽掉，这样通过DC/AC变换器320反向整流而在DC/AC变换器320的直流输入侧产生的母线电压会经过反灌缓起电路353的回路而施加在光伏组件上，从而利用电致发光效应生成检测图像。其中，反灌缓起电路353包括多个开关，分别编号为K1、K2一直到KN。这里，当组串式方案组件351包括N个需要进行检测的光伏组件，则有N个开关与N个光伏组件一一对应。每一个开关均有一端连接于对应 的光伏组件的直流输出端的正极端。例如，开关K1连接第1光伏组件300的直流输出端口正极端PV1+；开关K2连接第2光伏组件301的直流输出端口的正极端PV2+；开关KN连接第N光伏组件302的直流输出端口的正极端PVN+。每一个开关的另一端并联连接，也就是说，N个开关K1、K2…KN各自有一端与N个光伏组件的直流输出端的正极端连接，而另一端则连接于同一个结合点。反灌缓起电路353还包括电流检测器340用于检测流经反灌缓起电路353的直流电流的大小。N个开关K1、K2…KN在连接于同一个结合点之后再跟电流检测器340和其它器件串联连接而形成反灌缓起电路353的主要回路。如此，通过选择性地控制N个开关K1、K2…KN的闭合和断开，可以让组串式方案组件351中的全部或者部分光伏组件通过反灌缓起电路353接收反灌电流，也就是可以灵活配置参与检测的光伏组件的组合和数量。另外，流经电流检测器340的电流经过反灌缓起电路353其它器件后再通过处于闭合状态的开关传输到待检测的光伏组件，也就是说，对应的开关处于闭合状态的一个或多个光伏组件并入反灌缓起电路353的主要回路并分流流经电流检测器340的电流。
请继续参阅图3，反灌缓起电路353还包括主切换开关Kc和限流电感Ls。其中，限流电感Ls和主切换开关Kc串联连接在一起，然后再跟N个开关K1、K2…KN的结合点以及电流检测器340串联连接。通过主切换开关Kc的闭合和断开操作，可以设置包括限流电感Ls的主回路处于导通或者不导通的状态。当需要输送反向电流到光伏组件，DC/AC变换器320可以工作在反向整流的状态，也就是将DC/AC变换器320的交流输出侧的三相交流电整流后转换成DC/AC变换器320的直流输入侧的直流母线电压Vbus。这里，直流母线电压Vbus表示正极直流母线和负极直流母线之间的压差。在检测开始时，N个开关K1、K2…KN，主切换开关Kc的初始状态均是断开状态，这意味着反灌缓起电路353在光伏逆变器正常工作时处于断路的状态，并不干扰正常工作。假设第1光伏组件300需要进行检测，则与第1光伏组件300对应的开关K1先闭合一段时间t1，然后再闭合主切换开关Kc，这样反向电流经过电流检测器340，限流电感Ls，主切换开关Kc，还有开关K1之后传输到第1光伏组件300实现基于电致发光效应的检测。当检测结束时，首先断开主切换开关Kc，等主切换开关Kc断开一段时间之后，再断开开关K1。假设有多个光伏组件需要检测，例如第1光伏组件300、第2光伏组件301和第N光伏组件302均需要检测，则首先闭合对应的开关K1、K2和KN，等检测结束后最后断开开关K1、K2和KN。如此，根据要进行检测的光伏组件的组合和数量，首先闭合N个开关K1、K2…KN中与这些要检测的光伏组件对应的开关，同时保持其它开关处于断开状态，从而有利于灵活配置需要检测的光伏组件同时保证了高压环境下操作的安全性。而在检测结束时，则在最后才断开这些开关，从而有利于保护设备。也就是说，当检测结束而反灌缓起电路353切出时，与进行检测的光伏组件对应的开关在主切换开关Kc断开之后断开从而使得接入反灌缓起电路353的光伏组件与反灌缓起电路353断开连接，从而避免了检测结束时可能产生的冲击电流电压对光伏组件产生伤害，有利于保护设备。通过在闭合开关K1一段时间t1之后才闭合主切换开关Kc从而让主回路导通，如此设置可以通过限流电感Ls来实现对电流突然增大的抑制，也就是说限流电感的电感值越大则对电流突然增大的变化有更强的抑制作用。时间t1与限流电感Ls的电感值有关，时间t1也与需要进行检测的光伏组件的个数有关，需要检测的 光伏组件数量越多则时间t1更长。当有更多的光伏组件需要进行检测，则N个开关K1、K2…KN中会有更多的开关在开始检测时需要闭合一段时间t1，这意味着需要更长的等待时间来满足增加的能量需求。另外，反向电流的大小主要由直流母线电压Vbus来决定，因此在开始检测前和检测结束前，可以将直流母线电压Vbus调节到最低值，从而进一步减少冲击电流的影响。这里，反向电流也可以称作反灌电流，指的是为了检测光伏组件而通过DC/AC变换器320进行反向整流后施加在光伏组件上的电流。如此，通过操作反灌缓起电路353，实现了在检测光伏组件时能够有效抑制反向电流的突然变化从而避免冲击电流造成逆变器损坏，同时又有效保持能量利用效率。
请继续参阅图3，在一些示例性实施例中，DC/DC变换器部分352的DC/DC变换器采用单向升压变换器，也就是不适合用于电压电流从DC/DC变换器的直流输出端到直流输端的反向传输。为此，还包括外部旁路开关(未示出)来对单向的DC/DC变换器进行旁路处理。
请继续参阅图3，在一些示例性实施例中，还可以在DC/AC变换器320和交流出线端330之间包括滤波器(未示出)。滤波器可以用来抑制因为采用特定控制方式而产生的开关高频谐波，或者可以是并网滤波器，或者可以是参数可调的可调式滤波器从而应对变化的输出频率和等效阻抗。
请参阅图4，图4示出了本申请实施例提供的另一种实现方式的组串式光伏逆变器反灌缓起电路的原理图。组串式光伏逆变器通过由多个光伏组件构成的组串式方案组件输出直流电。其中，多个光伏组件输出的直流电压经过各自对应的DC/DC变换器升压后并联连接于同一个DC/AC变换器，从而可以针对每一个光伏组件的个别情况实现最大功率点跟踪也即实时侦测个别光伏组件的发电电压并实现最大功率输出。为此，每一个光伏组件的直流电输出端口连接于对应的DC/DC变换器的直流输入侧，使得每个光伏组件各自输出的直流电经过DC/DC变换器升压，也就是说，DC/DC变换器的直流输入侧的直流电压要小于DC/DC变换器的直流输出侧的直流电压。如图4所示，组串式方案组件451包括多个光伏组件编号为1到N，其中有第1光伏组件400、第2光伏组件401和第N光伏组件402。这里，正整数N用来表示组串式方案组件451中光伏组件的总数。每个光伏组件的直流电输出端口有正极端和负极端。第1光伏组件400的直流输出端口的正极端和负极端分别为PV1+和PV1-，第2光伏组件401的直流输出端口的正极端和负极端分别为PV2+和PV2-，第N光伏组件402的直流输出端口的正极端和负极端分别为PVN+和PVN-。每一个光伏组件的直流电输出端口连接于对应的DC/DC变换器的直流输入侧。第1光伏组件400的直流输出端口正极端PV1+和负极端PV1-分别连接于DC/DC变换器410的直流输入侧的正极端和负极端；第2光伏组件401的直流输出端口的正极端PV2+和负极端PV2-分别连接于DC/DC变换器411的直流输入侧的正极端和负极端；第N光伏组件402的直流输出端口的正极端PVN+和负极端PVN-分别连接于DC/DC变换器412的直流输入侧的正极端和负极端。与组串式方案组件451中的多个光伏组件一一对应的多个DC/DC变换器一起组成光伏逆变器的DC/DC变换器部分452。应当理解的是，组串式方案组件451输出的直流电经过DC/DC变换器部分452升压后，再经过DC/AC变换器420转换成交流电后传输到交 流出线端430。N个光伏组件的每一个都有对应的DC/DC变换器用来进行升压处理以便实现最大功率点跟踪。为此，当组串式方案组件451包括N个需要进行检测的光伏组件，DC/DC变换器部分452也相应的有N个DC/DC变换器。N个DC/DC变换器的直流输出端的正极端都连接于DC/AC变换器420的直流输入侧的正极端，而N个DC/DC变换器的直流输出端的负极端都连接于DC/AC变换器420的直流输入侧的负极端。在光伏逆变器的DC/DC变换器部分452和DC/AC变换器420之间是直流母线(未示出)，并且正极直流母线连接DC/AC变换器420的直流输入侧的正极端，负极直流母线连接DC/AC变换器420的直流输入侧的负极端。图4中以BUS+标识正极直流母线电压，和BUS-标识负极直流母线电压。DC/AC变换器420以三相逆变器为例，输出三相电压分别为Va、Vb、Vc。交流出线端430作为对外输出接口，可以将电能直接输出向负载也可能将电能返回电网。
请继续参阅图4，反灌缓起电路453布置在组串式方案组件451的直流输出端和DC/AC变换器420的直流输入侧之间。因为DC/DC变换器部分452也是布置在组串式方案组件451的直流输出端和DC/AC变换器420的直流输入侧之间，所以反灌缓起电路453与DC/DC变换器部分452整体上看是替代式的，也就是说，当需要进行光伏组件检测时，DC/DC变换器部分452可以通过旁路开关而屏蔽掉，这样通过DC/AC变换器420反向整流而在DC/AC变换器420的直流输入侧产生的母线电压会经过反灌缓起电路453的回路而施加在光伏组件上，从而利用电致发光效应生成检测图像。其中，反灌缓起电路453包括多个开关，分别编号为K1、K2一直到KN。这里，当组串式方案组件451包括N个需要进行检测的光伏组件，则有N个开关与N个光伏组件一一对应。每一个开关均有一端连接于对应的光伏组件的直流输出端的正极端。例如，开关K1连接第1光伏组件400的直流输出端口正极端PV1+；开关K2连接第2光伏组件401的直流输出端口的正极端PV2+；开关KN连接第N光伏组件402的直流输出端口的正极端PVN+。每一个开关的另一端并联连接，也就是说，N个开关K1、K2…KN各自有一端与N个光伏组件的直流输出端的正极端连接，而另一端则连接于同一个结合点。反灌缓起电路453还包括电流检测器440用于检测流经反灌缓起电路453的直流电流的大小。N个开关K1、K2…KN在连接于同一个结合点之后再跟电流检测器440和其它器件串联连接而形成反灌缓起电路453的主要回路。如此，通过选择性地控制N个开关K1、K2…KN的闭合和断开，可以让组串式方案组件451中的全部或者部分光伏组件通过反灌缓起电路453接收反灌电流，也就是可以灵活配置参与检测的光伏组件的组合和数量。另外，流经电流检测器440的电流经过反灌缓起电路453其它器件后再通过处于闭合状态的开关传输到待检测的光伏组件，也就是说，对应的开关处于闭合状态的一个或多个光伏组件并入反灌缓起电路453的主要回路并分流流经电流检测器440的电流。
请继续参阅图4，反灌缓起电路453还包括主切换开关Kc和降压式变换电路454。降压式变换电路454，也可以称作降压变换器(Buck Converter)或者Buck电路。降压式变换电路454包括二极管Db，电感Lb和开关Qb。其中，电感Lb和开关Qb串联连接后再跟主切换开关Kc串联连接在一起，然后再跟N个开关K1、K2…KN的结合点以及电流检测器440串联连接。二极管Db的阴极接在电感Lb和开关Qb之间，而阳极连接负极直流母线，也就是DC/AC变换器420的直流输入侧的负极端。通过施加脉冲宽度调制(Pulse  Width Modulation，PWM)信号到降压式变换电路454的开关Qb，可以实现受控的降压式直流到直流的转换。当需要输送反向电流到光伏组件，DC/AC变换器420可以工作在反向整流的状态，也就是将DC/AC变换器420的交流输出侧的三相交流电整流后转换成DC/AC变换器420的直流输入侧的直流母线电压Vbus。这里，直流母线电压Vbus表示正极直流母线和负极直流母线之间的压差。在检测开始时，N个开关K1、K2…KN，主切换开关Kc的初始状态均是断开状态，这意味着反灌缓起电路453在光伏逆变器正常工作时处于断路的状态，并不干扰正常工作。假设第1光伏组件400需要进行检测，则与第1光伏组件400对应的开关K1先闭合一段时间t1，然后再闭合主切换开关Kc，等主切换开关Kc闭合一段时间t1之后，向降压式变换电路454的开关Qb发送PWM控制信号，让开关Qb保持闭合状态从而让待检测的光伏组件上的电压缓慢增加，这样反向电流经过电流检测器440，主切换开关Kc，降压式变换电路454的开关Qb和电感Lb，还有开关K1之后传输到第1光伏组件400实现基于电致发光效应的检测。当检测结束时，首先断开主切换开关Kc，等主切换开关Kc断开一段时间之后，再断开开关K1和降压式变换电路454的开关Qb。假设有多个光伏组件需要检测，例如第1光伏组件400、第2光伏组件401和第N光伏组件402均需要检测，则首先闭合对应的开关K1、K2和KN，等检测结束后最后断开开关K1、K2和KN。如此，根据要进行检测的光伏组件的组合和数量，首先闭合N个开关K1、K2…KN中与这些要检测的光伏组件对应的开关，同时保持其它开关处于断开状态，从而有利于灵活配置需要检测的光伏组件同时保证了高压环境下操作的安全性。而在检测结束时，则在最后才断开这些开关，从而有利于保护设备。也就是说，当检测结束而反灌缓起电路453切出时，与进行检测的光伏组件对应的开关在主切换开关Kc断开之后断开从而使得接入反灌缓起电路453的光伏组件与反灌缓起电路453断开连接，从而避免了检测结束时可能产生的冲击电流电压对光伏组件产生伤害，有利于保护设备。通过降压式变换电路454的受控操作，可以实现降压式的直流到直流转换以及让光伏组件上的电压缓慢增加。另外，反向电流的大小主要由直流母线电压Vbus来决定，因此在开始检测前和检测结束前，可以将直流母线电压Vbus调节到最低值，从而进一步减少冲击电流的影响。这里，反向电流也可以称作反灌电流，指的是为了检测光伏组件而通过DC/AC变换器420进行反向整流后施加在光伏组件上的电流。如此，通过操作反灌缓起电路453，实现了在检测光伏组件时能够有效抑制反向电流的突然变化从而避免冲击电流造成逆变器损坏，同时又有效保持能量利用效率。
请继续参阅图4，在一些示例性实施例中，DC/DC变换器部分452的DC/DC变换器采用单向升压变换器，也就是不适合用于电压电流从DC/DC变换器的直流输出端到直流输端的反向传输。为此，还包括外部旁路开关(未示出)来对单向的DC/DC变换器进行旁路处理。
请继续参阅图4，在一些示例性实施例中，还可以在DC/AC变换器420和交流出线端430之间包括滤波器(未示出)。滤波器可以用来抑制因为采用特定控制方式而产生的开关高频谐波，或者可以是并网滤波器，或者可以是参数可调的可调式滤波器从而应对变化的输出频率和等效阻抗。
请参阅图1至图4，在一些示例性实施例中，与多个光伏组件一一对应的多个开关K1、K2…KN可以采用机械式开关例如继电器、接触器等，或者可以采用电子式开关例如IGBT、MOSFET等开关晶体管。
请参阅图5，图5示出了本申请实施例提供的另一种实现方式的组串式光伏逆变器的原理图。如图5所示，组串式光伏逆变器通过由多个光伏组件构成的组串式方案组件501输出直流电。其中，多个光伏组件输出的直流电压经过各自对应的DC/DC变换器升压后并联连接于同一个DC/AC变换器512，从而可以针对每一个光伏组件的个别情况实现最大功率点跟踪也即实时侦测个别光伏组件的发电电压并实现最大功率输出。为此，每一个光伏组件的直流电输出端口连接于对应的DC/DC变换器的直流输入侧，使得每个光伏组件各自输出的直流电经过DC/DC变换器升压，也就是说，DC/DC变换器的直流输入侧的直流电压要小于DC/DC变换器的直流输出侧的直流电压。这里，与组串式方案组件501中的多个光伏组件一一对应的多个DC/DC变换器一起组成光伏逆变器的DC/DC变换器部分511。DC/DC变换器部分511的DC/DC变换器采用双向变压器，也就是可以用于从直流输出端到直流输入端的反向传输。DC/DC变换器部分511和DC/AC变换器512一起组成光伏逆变器的反向整流器502。通过反向整流器502的内部控制，例如通过对DC/DC变换器部分511的DC/DC变换器施加PWM脉冲式控制，可以实现反向整流的电压缓慢增加地施加到光伏组件上。
请继续参阅图5，在一些示例性实施例中，还可以在DC/AC变换器512和交流出线端503之间包括滤波器(未示出)。滤波器可以用来抑制因为采用特定控制方式而产生的开关高频谐波，或者可以是并网滤波器，或者可以是参数可调的可调式滤波器从而应对变化的输出频率和等效阻抗。
请参阅图1至图5，由多个光伏组件构成的组串式方案组件可以是太阳能光伏阵列。DC/DC变换器和DC/AC变换器可以集成在一个设备中，也可以分为多个设备。本申请不限定DC/DC变换器和DC/AC变换器的具体物理形式，即逆变器可以由DC/DC变换器加DC/AC变换器组成，也可以仅由DC/AC变换器组成，不包括DC/DC变换器。在一些示例性实施例中，光伏逆变器由DC/DC变换器加DC/AC变换器组成。在另一些示例性实施例中，光伏逆变器仅包括DC/AC变换器。
本申请提供的具体实施例可以用硬件，软件，固件或固态逻辑电路中的任何一种或组合来实现，并且可以结合信号处理，控制和/或专用电路来实现。本申请具体实施例提供的设备或装置可以包括一个或多个处理器(例如，微处理器，控制器，数字信号处理器(DSP)，专用集成电路(ASIC)，现场可编程门阵列(FPGA)等)，这些处理器处理各种计算机可执行指令从而控制设备或装置的操作。本申请具体实施例提供的设备或装置可以包括将各个组件耦合在一起的系统总线或数据传输系统。系统总线可以包括不同总线结构中的任何一种或不同总线结构的组合，例如存储器总线或存储器控制器，外围总线，通用串行总线和/或利用多种总线体系结构中的任何一种的处理器或本地总线。本申请具体实施例提供 的设备或装置可以是单独提供，也可以是系统的一部分，也可以是其它设备或装置的一部分。
本申请提供的具体实施例可以包括计算机可读存储介质或与计算机可读存储介质相结合，例如能够提供非暂时性数据存储的一个或多个存储设备。计算机可读存储介质/存储设备可以被配置为保存数据，程序器和/或指令，这些数据，程序器和/或指令在由本申请具体实施例提供的设备或装置的处理器执行时使这些设备或装置实现有关操作。计算机可读存储介质/存储设备可以包括以下一个或多个特征：易失性，非易失性，动态，静态，可读/写，只读，随机访问，顺序访问，位置可寻址性，文件可寻址性和内容可寻址性。在一个或多个示例性实施例中，计算机可读存储介质/存储设备可以被集成到本申请具体实施例提供的设备或装置中或属于公共系统。计算机可读存储介质/存储设备可以包括光存储设备，半导体存储设备和/或磁存储设备等等，也可以包括随机存取存储器(RAM)，闪存，只读存储器(ROM)，可擦可编程只读存储器(EPROM)，电可擦可编程只读存储器(EEPROM)，寄存器，硬盘，可移动磁盘，可记录和/或可重写光盘(CD)，数字多功能光盘(DVD)，大容量存储介质设备或任何其他形式的合适存储介质。
以上是本申请实施例的实施方式，应当指出，本申请具体实施例描述的方法中的步骤可以根据实际需要进行顺序调整、合并和删减。在上述实施例中，对各个实施例的描述都各有侧重，某个实施例中没有详细描述的部分，可以参见其他实施例的相关描述。可以理解的是，本申请实施例以及附图所示的结构并不构成对有关装置或系统的具体限定。在本申请另一些实施例中，有关装置或系统可以包括比具体实施例和附图更多或更少的部件，或者组合某些部件，或者拆分某些部件，或者具有不同的部件布置。本领域技术人员将理解，在不脱离本申请具体实施例的精神和范围的情况下，可以对具体实施例记载的方法和设备的布置，操作和细节进行各种修改或变化；在不脱离本申请实施例原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也视为本申请的保护范围。

Claims (17)

  1. 一种光伏逆变器的反灌缓起电路，所述反灌缓起电路连接在所述光伏逆变器的DC/AC变换器的直流输入侧和太阳能光伏阵列的输出侧之间，其特征在于，所述反灌缓起电路包括：
    多个支路开关，其中，所述太阳能光伏阵列包括多个光伏组件，所述多个支路开关与所述多个光伏组件一一对应，所述多个支路开关闭合时对应的光伏组件接入所述反灌缓起电路；
    主切换开关，其中，所述多个支路开关的一端连接对应的光伏组件另一端均连接所述主切换开关；
    其中，所述主切换开关在所述支路开关闭合之后闭合以使得所述DC/AC变换器反向整流产生的反灌电流经过所述DC/AC变换器的直流输入侧和所述反灌缓起电路到所述接入所述反灌缓起电路的光伏组件。
  2. 根据权利要求1所述的反灌缓起电路，其特征在于，所述反灌缓起电路还包括限流开关和限流电阻，其中，所述限流开关和所述限流电阻串联连接后与所述主切换开关并联连接，所述限流开关在所述支路开关闭合之后闭合，所述主切换开关在所述限流开关闭合经过第一时间之后闭合，所述限流开关在所述主切换开关闭合经过第二时间之后断开，所述第二时间根据所述DC/AC变换器的直流输入侧的母线电压确定。
  3. 根据权利要求2所述的反灌缓起电路，其特征在于，所述反灌缓起电路还包括限流电感，所述限流开关和所述限流电阻串联连接后与所述主切换开关并联连接再与所述限流电感串联连接。
  4. 根据权利要求1所述的反灌缓起电路，其特征在于，所述反灌缓起电路还包括限流开关和限流电阻，其中，所述限流开关和所述限流电阻并联连接后与所述主切换开关串联连接，所述主切换开关在所述支路开关闭合之后闭合，所述限流开关在所述主切换开关闭合经过第一时间之后闭合。
  5. 根据权利要求1所述的反灌缓起电路，其特征在于，所述反灌缓起电路还包括限流电感，所述限流电感串联连接于所述主切换开关，所述主切换开关在所述支路开关闭合经过第一时间之后闭合，所述第一时间根据所述限流电感的电感值和所述接入所述反灌缓起电路的光伏组件的数量确定。
  6. 根据权利要求1所述的反灌缓起电路，其特征在于，所述反灌缓起电路还包括降压式变换电路，所述降压式变换电路包括电感和开关管，所述电感和所述开关管串联连接后与所述主切换开关串联连接，所述降压式变换电路的开关管在脉冲宽度调制信号控制下保持闭合以使得所述反灌电流经过所述降压式变换电路。
  7. 根据权利要求1-6任一项所述的反灌缓起电路，其特征在于，所述反灌电流的大小根据所述DC/AC变换器的直流输入侧的母线电压调节。
  8. 根据权利要求7所述的反灌缓起电路，其特征在于，所述DC/AC变换器的直流输入侧的母线电压在检测开始前和检测结束前调节到最低值。
  9. 根据权利要求1-8任一项所述的反灌缓起电路，其特征在于，所述支路开关在所述主切换开关断开之后断开从而使得所述接入所述反灌缓起电路的光伏组件与所述反灌缓起电路断开连接。
  10. 一种光伏逆变器，其特征在于，所述光伏逆变器包括多个双向DC/DC变换器，所述多个双向DC/DC变换器连接太阳能光伏阵列的多个光伏组件，所述光伏逆变器通过所述多个双向DC/DC变换器在脉冲宽度调制信号下的脉冲式控制从而将反向整流电压施加到对应的光伏组件。
  11. 一种对太阳能光伏阵列进行电致发光检测的方法，所述太阳能光伏阵列包括多个光伏组件，与所述太阳能光伏阵列连接的光伏逆变器包括DC/AC变换器，反灌缓起电路连接在所述光伏逆变器的DC/AC变换器的直流输入侧和所述太阳能光伏阵列的输出侧之间，所述反灌缓起电路包括与所述多个光伏组件一一对应的多个支路开关和主切换开关，所述多个支路开关的一端连接对应的光伏组件另一端均连接所述主切换开关，其特征在于，所述方法包括：
    闭合所述多个支路开关中的一个或多个以将对应的光伏组件接入所述反灌缓起电路；
    闭合所述多个支路开关中的一个或多个之后闭合所述主切换开关，以使得所述DC/AC变换器反向整流产生的反灌电流经过所述DC/AC变换器的直流输入侧和所述反灌缓起电路到所述接入所述反灌缓起电路的光伏组件；和
    根据所述接入所述反灌缓起电路的光伏组件在所述反灌电流作用下的电致发光效应检测出有缺陷的光伏组件。
  12. 根据权利要求11所述的方法，其特征在于，所述反灌缓起电路还包括限流开关和限流电阻，所述限流开关和所述限流电阻串联连接后与所述主切换开关并联连接，所述闭合所述多个支路开关中的一个或多个之后闭合所述主切换开关包括：
    闭合所述多个支路开关中的一个或多个之后闭合所述限流开关，
    闭合所述限流开关经过第一时间之后闭合所述主切换开关，
    闭合所述主切换开关经过第二时间之后断开所述限流开关，
    其中，所述第二时间根据所述DC/AC变换器的直流输入侧的母线电压确定。
  13. 根据权利要求11所述的方法，其特征在于，所述反灌缓起电路还包括限流开关和限流电阻，其中，所述限流开关和所述限流电阻并联连接后与所述主切换开关串联连接，所述闭合所述多个支路开关中的一个或多个之后闭合所述主切换开关包括：
    闭合所述多个支路开关中的一个或多个之后闭合所述主切换开关；
    闭合所述主切换开关经过第一时间后闭合所述限流开关。
  14. 根据权利要求11所述的方法，其特征在于，所述反灌缓起电路还包括限流电感，所述限流电感串联连接于所述主切换开关，所述闭合所述多个支路开关中的一个或多个之后闭合所述主切换开关包括：
    闭合所述多个支路开关中的一个或多个经过第一时间之后闭合所述主切换开关，其中，所述第一时间根据所述限流电感的电感值和所述接入所述反灌缓起电路的光伏组件的数量确定。
  15. 根据权利要求11-14任一项所述的方法，其特征在于，所述反灌电流的大小根据所述DC/AC变换器的直流输入侧的母线电压调节。
  16. 根据权利要求15所述的方法，其特征在于，所述方法还包括：
    在检测开始前和检测结束前调节所述DC/AC变换器的直流输入侧的母线电压到最低值。
  17. 根据权利要求11-16任一项所述的方法，其特征在于，所述方法还包括：
    检测结束时断开所述主切换开关之后断开所述支路开关从而使得所述接入所述反灌缓起电路的光伏组件与所述反灌缓起电路断开连接。
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