WO2021208632A1 - 一种快速关断方法、光伏组件关断器和光伏系统 - Google Patents

一种快速关断方法、光伏组件关断器和光伏系统 Download PDF

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Publication number
WO2021208632A1
WO2021208632A1 PCT/CN2021/079465 CN2021079465W WO2021208632A1 WO 2021208632 A1 WO2021208632 A1 WO 2021208632A1 CN 2021079465 W CN2021079465 W CN 2021079465W WO 2021208632 A1 WO2021208632 A1 WO 2021208632A1
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WIPO (PCT)
Prior art keywords
photovoltaic module
photovoltaic
shutdown
start signal
inverter
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PCT/CN2021/079465
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English (en)
French (fr)
Inventor
杨宇
俞雁飞
王新宇
徐君
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阳光电源股份有限公司
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Application filed by 阳光电源股份有限公司 filed Critical 阳光电源股份有限公司
Priority to US17/915,396 priority Critical patent/US20230126969A1/en
Priority to EP21789183.7A priority patent/EP4138244A4/en
Priority to AU2021255244A priority patent/AU2021255244B2/en
Publication of WO2021208632A1 publication Critical patent/WO2021208632A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H02H7/122—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/20—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for electronic equipment
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/04—Arrangements for preventing response to transient abnormal conditions, e.g. to lightning or to short duration over voltage or oscillations; Damping the influence of dc component by short circuits in ac networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
    • H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for dc applications
    • 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
    • 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
    • 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 invention belongs to the technical field of photovoltaic grid-connected power generation, and more specifically, relates to a quick shut-off method, a photovoltaic module shut-off device and a photovoltaic system.
  • Photovoltaic power generation technology is widely used as a renewable energy power generation technology.
  • the photovoltaic array outputs direct current, which is converted into alternating current by an inverter and then transmitted to the grid.
  • the voltage of the series photovoltaic array is very high. In order to improve the safety of the photovoltaic system, it is required that the photovoltaic system can be turned off quickly; Whether the component realizes electric energy output or not.
  • the central controller of the system needs to continuously send a heartbeat communication signal or a periodic excitation pulse source to maintain each switch in an open state.
  • the continuous transmission of heartbeat communication signals or periodic excitation pulse sources will cause the central controller's software resources to occupy a large amount, and at the same time, the power loss is also large.
  • the purpose of the present invention is to provide a quick shutdown method, photovoltaic module shutdown device and photovoltaic system, which are used to reduce the software resource occupation and power loss of the central controller.
  • the first aspect of the present invention discloses a fast shutdown method, including:
  • the photovoltaic module shut-off device in the photovoltaic system receives the start signal
  • the photovoltaic module shut-off device controls itself to be turned on, so that the photovoltaic module connected to the photovoltaic module realizes electric energy output;
  • the photovoltaic module shutdown device detects its own state parameters, and judges whether the corresponding inverter channel in the photovoltaic system has a fault;
  • the photovoltaic module cut-off device controls itself to shut down, so that the photovoltaic module connected to it stops the electric energy output;
  • the photovoltaic module shut-off device maintains its own turn-on.
  • the photovoltaic module shutdown device judging whether the corresponding inverter channel in the photovoltaic system has a fault, including:
  • the photovoltaic module shut-off device judges whether its own state parameter is dynamically changing
  • the photovoltaic module shutdown device determines that the corresponding inverter channel is faulty
  • the photovoltaic module switcher determines that the corresponding inverter channel does not have a fault.
  • the photovoltaic module shutdown device judging whether the corresponding inverter channel in the photovoltaic system has a fault, including:
  • the photovoltaic module switch-off device judges whether there is an arc on the corresponding DC bus according to the state parameter
  • the photovoltaic module switcher determines that the corresponding inverter channel is faulty
  • the photovoltaic module switcher determines that the corresponding inverter channel does not have a fault.
  • the photovoltaic module shutdown device in the photovoltaic system receives a start signal, including:
  • the photovoltaic module shutdown device receives the startup signal during its own startup time period or an inverter failure recovery waiting time period.
  • the method further includes:
  • the photovoltaic module shut-off device After the photovoltaic module shut-off device has auxiliary power supply, it detects its own output current to determine whether the inverter in the photovoltaic system is in a working state;
  • the step of controlling the turn-on of the photovoltaic module switcher is executed.
  • the method further includes:
  • the photovoltaic module shutdown device judges whether the corresponding inverter channel continues to fail for a preset time
  • the step of controlling the shutdown of the photovoltaic module to shut off the photovoltaic module connected to the photovoltaic module is executed.
  • the preset time is greater than the step time for tracking the maximum power point of the inverter in the photovoltaic system, and is less than the required time for rapid shutdown of the photovoltaic system.
  • it also includes:
  • the inverter in the photovoltaic system applies voltage perturbation to the DC bus in the photovoltaic system to change the state parameters of the photovoltaic component shut-off device and prevent the photovoltaic component shut-off device from being turned off by mistake.
  • the second aspect of the present invention discloses a photovoltaic module shutdown device, including: a switch unit, a bypass diode, a drive unit, a parameter acquisition module, a processor, and a start signal receiving unit; wherein:
  • the parameter collection module is used to collect the state parameters of the photovoltaic module switcher, and output the collected state parameters to the processor;
  • the start signal receiving unit is configured to receive a start signal, and output the start signal to the processor;
  • the switch unit is arranged on the positive branch or the negative branch of the photovoltaic module switch, and is used to realize the on or off of the photovoltaic module switch according to the control of the processor;
  • the bypass diode is used to realize the bypass function of the photovoltaic module shut-off device when the photovoltaic module shut-off device is turned off;
  • the output terminal of the processor is connected to the control terminal of the switch unit through the drive unit; the processor is used to combine the start signal receiving unit, the parameter collection module, the drive unit, and the switch unit , So that the photovoltaic module shut-off device can realize the corresponding fast shut-off method disclosed in the first aspect of the present invention.
  • the parameter collection module includes: a voltage sampling unit and at least one current sampling unit;
  • the voltage sampling unit is configured to collect the input voltage of the photovoltaic module switch, and output the collected input voltage to the processor;
  • the current sampling unit is used to collect the input current/output current of the photovoltaic module switch, and output the collected input current/output current to the processor.
  • the start signal receiving unit is arranged on the negative branch of the photovoltaic module switch, between the anode of the bypass diode and the output terminal of the photovoltaic module switch;
  • the current sampling unit is arranged on the positive branch of the photovoltaic module switch, the cathode of the bypass diode and the output terminal of the photovoltaic module switch Or, the current sampling unit is arranged on the negative branch of the photovoltaic module switch, between the anode of the bypass diode and the start signal receiving unit;
  • the first current sampling unit is arranged on the negative branch of the photovoltaic module switcher. Between the negative pole of the input terminal of the photovoltaic module switch and the start signal receiving unit, the second current sampling unit is arranged at the connection point of the first current sampling unit and the start signal receiving unit and the side Between the anodes of the diodes.
  • the third aspect of the present invention discloses a photovoltaic system, including: at least one shutdown system and at least one inverter, the shutdown system includes: a DC bus, a start signal generator, N photovoltaic modules and N such
  • N is a positive integer, where:
  • each of the photovoltaic module shutdown devices are cascaded, and the input terminals of each photovoltaic module shutdown device are respectively connected to each photovoltaic module in a one-to-one correspondence; each of the photovoltaic module shutdown devices is cascaded
  • the rear positive pole is connected to the positive pole of the corresponding DC interface of the inverter through the positive pole of the DC bus; the negative pole of each of the photovoltaic module switches after cascading is connected to the corresponding DC of the inverter through the negative pole of the DC bus.
  • the negative pole of the interface is connected;
  • the start signal generator is used to send a start signal to each of the photovoltaic module shutdown devices in the same shutdown system.
  • start signal generator when used to send a start signal to each of the photovoltaic module shutdown devices in the same shutdown system, it is specifically used to:
  • the inverter is further configured to apply voltage disturbances to each of the DC buses to change the state parameters of the photovoltaic module shut-off device and prevent the photovoltaic module shut-off device from being turned off by mistake.
  • the activation signal is a power line carrier signal, a wireless communication signal, or an analog pulse signal.
  • the start signal when the start signal is a power line carrier signal, the start signal complies with the fast shutdown signal specification formulated by the SunSpec Alliance.
  • the start signal generator is integrated in the inverter, or is independently placed on the DC bus.
  • the present invention provides a quick shut-off method.
  • the photovoltaic module shut-off device controls itself to turn on so that the connected photovoltaic module realizes electric energy output; then, it can detect its own state parameters , To determine whether the corresponding inverter channel in the photovoltaic system is faulty; if the corresponding inverter channel in the photovoltaic system fails, it will control itself to shut down so that the photovoltaic components connected to it stop the power output; and if the corresponding inverter channel in the photovoltaic system is If the inverter channel does not fail, it will always maintain its own opening; thus, there is no need for the central controller to continuously send signals or pulses to control the opening of the photovoltaic module breaker, which reduces the software resource occupation and power loss of the central controller.
  • FIG. 1 is a flowchart of a fast shutdown method provided by an embodiment of the present invention
  • FIG. 2 is a flowchart of another fast shutdown method provided by an embodiment of the present invention.
  • FIG. 3 is a flowchart of another fast shutdown method provided by an embodiment of the present invention.
  • Fig. 4 is a schematic diagram of a photovoltaic module shut-off device provided by an embodiment of the present invention.
  • Fig. 5 is a schematic diagram of another photovoltaic module shutdown device provided by an embodiment of the present invention.
  • Fig. 6 is a schematic diagram of another photovoltaic module shutdown device provided by an embodiment of the present invention.
  • Fig. 7 is a schematic diagram of a photovoltaic system provided by an embodiment of the present invention.
  • Figure 8 is a schematic diagram of another photovoltaic system provided by an embodiment of the present invention.
  • FIG. 9 is a schematic diagram of another photovoltaic system provided by an embodiment of the present invention.
  • Figure 10 is a typical voltage and current curve diagram of photovoltaic modules provided by the implementation of the present invention.
  • Fig. 11 is a schematic diagram of another photovoltaic module shutdown device provided by an embodiment of the present invention.
  • the terms “include”, “include” or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes no Other elements clearly listed, or also include elements inherent to this process, method, article, or equipment. If there are no more restrictions, the element defined by the sentence “including a" does not exclude the existence of other identical elements in the process, method, article, or equipment that includes the element.
  • the embodiment of the present invention provides a quick shut-off method to solve the need for the central controller of the system in the prior art to continuously send a heartbeat communication signal or periodic excitation pulse source to maintain each shut-off device in an open state, which leads to the central control
  • the software resource of the device takes up a lot, and the power loss is also a big problem.
  • This fast shutdown method includes:
  • the photovoltaic module shut-off device in the photovoltaic system receives a start signal.
  • the external equipment of the photovoltaic module switcher is generated and sent by a start-up signal generator.
  • the start-up signal can be a power line carrier signal, a wireless communication signal or an analog pulse signal; Within the scope of protection applied for.
  • the SunSpec Alliance is a trade alliance composed of more than 100 solar and storage distributed energy industry participants; the SunSpec specifications set by the SunSpec Alliance apply to most solar photovoltaic system components and are Adopted worldwide, the SunSpec specification specifies a unified power line carrier communication signal for fast shutdown equipment. Therefore, when the start signal is a power carrier signal, the start signal complies with the fast shutdown signal specification formulated by the SunSpec Alliance, which enhances the compatibility of the circuit.
  • the photovoltaic module switch-off device receives the start signal, that is, the corresponding start signal is generated and sent by the device such as the start signal
  • the generator sends a start signal during the start-up time period of the photovoltaic module switcher or the waiting period of the inverter failure recovery.
  • step S102 when the photovoltaic module shutdown device receives the start signal, it indicates that the inverter connected to the photovoltaic module shutdown device allows the photovoltaic module shutdown device to enter the working state, that is, step S102 is executed.
  • step S102 is executed; in addition, the start signal may not be continuously sent.
  • step S102 is executed.
  • the photovoltaic module switch-off device controls itself to turn on, so that the photovoltaic module connected to the photovoltaic module realizes electric energy output.
  • the opening of the photovoltaic module switch-off is different from the realization of the communication function; the opening of the photovoltaic module switch-on refers to the opening of its internal connection, so that the connected photovoltaic module can realize the electric energy output, and on the photovoltaic module switch-off When there is auxiliary power supply, the photovoltaic module switcher can realize the communication function.
  • step S103 is executed.
  • the photovoltaic module shut-off device detects its own state parameters, and judges whether the corresponding inverter channel in the photovoltaic system has a fault.
  • the state parameter can be: input parameters, such as input voltage (that is, the output voltage of the corresponding photovoltaic component) and input current (that is, the output current of the corresponding photovoltaic component); it can also be: output parameters, such as output current and output voltage.
  • the faults existing in the inverter channel include the inverter's corresponding DC interface short-circuit fault, DC bus short-circuit fault, and DC bus arcing fault. If any of the above-mentioned faults exists, the inverter cannot work normally. , There is a risk of circuit safety.
  • step S104 the photovoltaic module needs to stop power output, that is, step S104; and if the corresponding inverter channel does not fail, the photovoltaic module can continue to achieve power output, that is, step S105 .
  • the photovoltaic module shut-off device controls itself to shut down, so that the photovoltaic module connected to the photovoltaic module stops the electric energy output.
  • the shutdown device of the photovoltaic module keeps itself turned on.
  • the photovoltaic module shutdown device can enter the on state after receiving the start signal, and then the photovoltaic module shutdown device detects and judges its own state parameters to determine whether to maintain the on state without the central controller continuously sending Signals or pulses are used to control the opening of the photovoltaic module switch-off. After the photovoltaic module switch-off is opened, the start signal is no longer needed, which reduces the software resource occupation and power consumption of the central controller.
  • the inverter is required to have a fault recovery time.
  • the fault recovery time is usually tens of seconds to several minutes.
  • the fault recovery time is greater than the fast shutdown time required by the system, such as the NEC 2017 30 seconds.
  • the method further includes: the photovoltaic module switcher judging whether the corresponding inverter channel continues to fail for longer than the preset time, that is, the above-mentioned fault recovery time. If the corresponding inverter channel continues to fail for as long as the preset time, step S104 is executed, and the photovoltaic module shut-off device controls itself to shut down, so that the photovoltaic module connected to it stops power output.
  • the preset time that is, the above-mentioned fault recovery time, is greater than the step time for tracking the maximum power point of the inverter in the photovoltaic system, and is less than the required time for rapid shutdown of the photovoltaic system.
  • step S103 the specific process of judging whether the corresponding inverter channel in the photovoltaic system has a failure involved in step S103 is different, specifically:
  • step S103 involves determining whether the corresponding inverter channel in the photovoltaic system is faulty, see Figure 2, including:
  • S201 The photovoltaic module shut-off device judges whether its own state parameter is dynamically changing.
  • the state parameters are the input current and the input voltage, it is determined whether the input current and the input voltage are both dynamically changing. If the status parameters are output current and output voltage, judge whether the output current and output voltage are dynamically changing.
  • whether it is in a dynamic change can be obtained by comparing the previous sampled value with the current sampled value; for example, if the previous sampled value is inconsistent with the current sampled value, it is determined that it is in a dynamic change. If the current sampling value is consistent, it is determined that it is not in dynamic change. It can also be judged whether the number of times that the previous sampled value is continuously consistent with the current sampled value is greater than or equal to the preset value. If the number of consecutively consistent times of the previous sampled value with the current sampled value is greater than or equal to the preset value, it is determined that it is not in dynamic change. If the number of consecutive times that the previous sampled value is consistent with the current sampled value is less than the preset value, it is determined that it is in dynamic change.
  • step 201 is not limited, and it depends on the actual situation, and all are within the protection scope of the present application.
  • the above state parameters are not limited to input current, input voltage, output current, and output voltage.
  • Other parameters that can characterize the output parameters/output parameters of the photovoltaic module switch are all within the protection scope of the present application.
  • the inverter in the photovoltaic system dynamically adjusts the voltage and current of the DC bus in the photovoltaic system to track the maximum power point, so that the output power of each photovoltaic component corresponding to the DC bus is maximized. Therefore, when the inverter channel is not faulty, the voltage and current of the DC bus will dynamically change. Correspondingly, the state parameters of the corresponding photovoltaic module switch will also dynamically change; that is, due to the maximum power point tracking The reason will cause the output characteristics of each photovoltaic module to fluctuate continuously. This fluctuation is an inherent characteristic of the inverter during normal operation; the photovoltaic module switcher can use this inherent characteristic to perform fault judgment.
  • the inverter in order to avoid erroneous shutdown of the photovoltaic module shutdown device, when the inverter is not tracking the maximum power point at a constant power, it can also actively adjust the voltage and current of the DC bus to make the state parameters of each photovoltaic module shutdown device. In dynamic change. Furthermore, if the photovoltaic module switcher determines that its state parameters are not dynamically changing, it means that the current state of the inverter channel does not meet the normal operating characteristics, and it can be determined that the corresponding inverter channel is faulty, and step S104 is executed.
  • step S105 is executed.
  • the photovoltaic module switcher judges whether there is an arc on the corresponding DC bus.
  • the photovoltaic module switch-off device judges whether there is a DC arcing fault based on its own input parameters (ie, photovoltaic module output voltage and output current).
  • the current noise is mainly used to determine whether an arc occurs on the corresponding DC bus, that is, a DC arc fault. If the current noise is greater than the corresponding preset value, it is determined that an arc occurs on the corresponding DC bus, that is, there is a DC arc fault. If the current noise is less than or equal to the corresponding preset value, it is determined that there is no arc on the corresponding DC bus, that is, there is no DC arc fault.
  • step S104 If an arc occurs on the corresponding DC bus, it is determined that the corresponding inverter channel is faulty and step S104 is executed; and if there is no arc on the corresponding DC bus, it is determined that the corresponding inverter channel does not have a fault, and step S105 is executed.
  • the DC arc will cause the temperature of the contact part to rise sharply.
  • the continuous arc will produce a high temperature of 3000-7000 °C, and accompanied by high temperature carbonization of the surrounding components, the lighter will fuse the fuse and the wire. Cables, the worst ones, burn down components and equipment and cause fires.
  • the photovoltaic system will have major safety issues.
  • the state parameters of the photovoltaic module switcher are used to determine whether an arc occurs on the corresponding DC bus, and then when an arc occurs on the corresponding DC bus, control itself to shut down and stop the photovoltaic module from outputting electrical energy. This avoids the occurrence of major safety issues in the photovoltaic system when the inverter does not have an arc fault interrupter or the arc fault interrupter fails to function.
  • Fig. 11 may also include: S401, the inverter in the photovoltaic system applies voltage disturbance to the DC bus in the photovoltaic system, In order to change the state parameters of the photovoltaic module shut-off device, to avoid the wrong turn-off of the photovoltaic module shut-off device.
  • the voltage and current of each DC bus in the photovoltaic system are continuously adjusted to track the maximum power point.
  • Typical operating points include open-circuit operating point, short-circuit operating point and maximum power point.
  • the output voltage of the photovoltaic module is the highest, which is the open-circuit voltage, the output current is zero, and the output power is zero;
  • the short-circuit operating point the output voltage of the photovoltaic module is zero, and the output current is the largest, which is the short-circuit current.
  • the output power is zero; at the maximum power point, the output voltage of the photovoltaic module is the maximum power point voltage, the output current is the maximum power point current, and the output power is the maximum.
  • the inverter dynamically adjusts the voltage and current of the DC bus for maximum power point tracking, so that the output power of each photovoltaic module corresponding to the DC bus is maximized.
  • the commonly used maximum power point tracking method is the hill climbing method; specifically, the inverter actively applies disturbance to the voltage on the DC bus to increase or decrease the voltage, and determine the position of the maximum power point according to the change in voltage and power after the disturbance.
  • the output condition of the control DC bus tends to be at the maximum power point.
  • the output voltage and current characteristics of the photovoltaic module are dynamically changing. When the photovoltaic module is stable, its power fluctuates around the maximum power point, such as in the range from point M to point N.
  • the photovoltaic module switcher uses its own state parameters, that is, the inherent output characteristics of the inverter during normal operation, to detect a fault in the system, and after detecting the fault, it disconnects the corresponding photovoltaic Components.
  • the inverter needs to work in a constant power state, that is, the inverter does not perform maximum power point tracking, so that the voltage and current state of the DC bus hardly change.
  • the inverter can deliberately impose a short voltage disturbance on the DC bus, so that the voltage and current of the DC bus fluctuate, and then the PV module switcher remains on.
  • the light intensity is weak, the output current of the photovoltaic module is low, and the current sampling module in the photovoltaic module switcher may be affected by accuracy and bias, and the current sampled is not accurate.
  • the inverter can also impose a short voltage disturbance on the DC bus.
  • the implementation of voltage disturbance includes the inverter suddenly increasing the output power, causing the voltage on the DC bus to drop; or suddenly reducing the output power, causing the voltage on the DC bus to increase.
  • the above-mentioned power change time is relatively short and will not have a significant impact on the average output power of the inverter.
  • voltage disturbance is applied to the DC bus in the photovoltaic system through the inverter. Even if the inverter is working in a constant power state, that is, the inverter does not track the maximum power point, the voltage disturbance is still applied to the DC bus. Change the state parameters of the photovoltaic module shut-off device to prevent the photovoltaic module shut-off device from being turned off by mistake due to the inverter working in a constant power state, and improve the diagnostic accuracy of the temperature rise and fall.
  • the embodiment of the present invention provides a photovoltaic module shut-off device, see FIG. 4, including: a switch unit 401, a bypass diode 404, a driving unit 403, a parameter collection module (the voltage sampling unit 402 and the current sampling unit shown in FIG. 4) Unit 406), processor 405, and start signal receiving unit 407; among them:
  • the parameter collection module is used to collect the state parameters of the photovoltaic module switcher, and output the collected state parameters to the processor 405.
  • the start signal receiving unit 407 is arranged on the negative branch of the photovoltaic module switch, between the anode of the bypass diode 404 and the output terminal Uout- of the photovoltaic module switch; specifically, the input terminal of the start signal receiving unit 407 is positive The pole is connected with the output terminal Uout- of the photovoltaic module switch, the input terminal of the start signal receiving unit 407 is connected to the input terminal Uin- of the photovoltaic module switch directly or through a parameter acquisition module; the start signal receiving unit 407 is used It receives the start signal and outputs the start signal to the processor 405.
  • the switch unit 401 is arranged on the negative branch (not shown); or, the switch unit 401 is arranged on the positive branch of the photovoltaic module switch. Specifically, as shown in FIG. 4, the input end of the switch unit 401 is connected to the photovoltaic module. The input terminal of the switch is connected to the anode Uin+, the output terminal of the switch unit 401 is connected to the cathode of the bypass diode 404, and the connection point is connected to the output terminal of the photovoltaic module switcher Uout+ directly or through a parameter collection module.
  • the switch unit 401 is configured to be turned on or off under the control of the processor 405, so that the connection of the photovoltaic module switch itself is turned on or off.
  • the switch unit 401 is a semiconductor switch device, that is, the switch unit 401 may be an IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor), or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor, metal Oxide Semiconductor Field Effect Transistor).
  • the switch unit 401 may be formed by a series or parallel combination of a plurality of semiconductor switch devices, which will not be repeated here, and all are within the protection scope of the present application.
  • the anode of the bypass diode 404 is connected directly or through the parameter acquisition module to the cathode of the input terminal of the start signal receiving unit 407; the bypass diode 404 is used to realize the photovoltaic module turn off when the photovoltaic module switch is off, that is, the switch unit 401 is off. Bypass function of the breaker.
  • the output terminal of the parameter acquisition module and the output terminal of the start signal receiving unit 407 are both connected to the corresponding input terminal of the processor 405; the output terminal of the processor 405 is connected to the control terminal of the switch unit 401 through the drive unit 403.
  • the photovoltaic module shutdown device is used for the fast shutdown method provided in any of the above embodiments. For details, refer to the above embodiments, and will not be repeated here.
  • the parameter collection module is used to collect the state parameters of the photovoltaic module switcher, and the processor 405 determines whether the corresponding inverter channel in the photovoltaic system is faulty; and the switch unit 401 is controlled to perform corresponding actions according to the determination result This avoids the need to continuously send heartbeat signals or analog pulses with similar functions for judgment, and reduces the software resources and power consumption of the system.
  • the parameter collection module includes: a voltage sampling unit 402 and at least one current sampling unit (406 as shown in FIG. 4 and FIG. 5, and 406a and 406b as shown in FIG. 6).
  • the positive and negative terminals of the input terminal of the voltage sampling unit 402 are respectively connected to the positive and negative terminals of the input terminal of the photovoltaic module switch, and the output terminal of the voltage sampling unit 402 is connected to the processor 405; the voltage sampling unit 402 is used to collect the input voltage of the photovoltaic module switch, And output the collected input voltage to the processor 405.
  • the current sampling unit is used to collect the input current/output current of the photovoltaic module switch, and output the collected input current/output current to the processor 405.
  • the number of current sampling units can be one or two. The two cases including one current sampling unit and two current sampling units will be described below, specifically:
  • the current sampling unit 406 is arranged on the positive branch of the photovoltaic module switch, the cathode of the bypass diode 404 and the output of the photovoltaic module switch
  • the output terminal of the specific current sampling unit 406 is connected to the processor 405; one end of the current sampling unit 406 is connected to the output terminal of the switch unit 401 and the cathode of the bypass diode 404, and the other of the current sampling unit 406 One end is connected to the output terminal positive Uout+ of the photovoltaic module switcher. Or, as shown in FIG.
  • the current sampling unit 406 is arranged on the negative branch of the photovoltaic module switcher, between the anode of the bypass diode 404 and the start signal receiving unit 407; specifically, one end of the current sampling unit 406 is connected to the start The input terminal of the signal receiving unit 407 is connected to the negative pole, and the other end of the current sampling unit 406 is respectively connected to the anode of the bypass diode 404 and the negative pole of the input terminal Uin- of the photovoltaic module switch.
  • the current sampled by the current sampling unit 406 is the output current of the photovoltaic module, that is, the input current of the photovoltaic module switch; when the switching unit 401 is turned off, the current sampling unit 406 The sampled current is the current of the bypass diode 404, that is, the output current of the photovoltaic module switch.
  • the first current sampling unit 406a is arranged on the negative branch of the photovoltaic module switch, and the input terminal Uin- of the photovoltaic module switch is connected to Between the start signal receiving unit 407, the second current sampling unit 406b is arranged between the connection point of the first current sampling unit 406a and the start signal receiving unit 407 and the anode of the bypass diode 404; specifically, the first current sampling unit 406a
  • the output end of the second current sampling unit 406b and the output end of the second current sampling unit 406b are both connected to the processor 405; one end of the second current sampling unit 406b is connected to the anode of the bypass diode 404; the other end of the second current sampling unit 406b is connected to the first One end of the current sampling unit 406a is connected to the negative input terminal of the start signal receiving unit 407; the other end of the first current sampling unit 406a is connected to the negative input terminal Uin- of the photovoltaic
  • the first current sampling unit 406a is used to sample the output current of the photovoltaic module, that is, the input current of the photovoltaic module switch, and the second current sampling unit 406b is used to sample the current of the bypass diode 404, that is, the output current of the photovoltaic module switch. .
  • the above-mentioned current collection unit may be a current sensor, or other devices capable of collecting current, which will not be repeated here, and all are within the protection scope of the present application.
  • DC arcing detection at the photovoltaic module end can be performed, and the DC arcing detection at the photovoltaic module end can detect parallel arcing faults in the system.
  • the embodiment of the present invention provides a photovoltaic system, referring to Figure 7 ( Figure 7 shows a shutdown system as an example), including: at least one shutdown system and at least one inverter 204, the shutdown system includes: DC bus 203.
  • Start signal generator 205 N photovoltaic modules 201 and N photovoltaic module shut-off devices 202, where N is a positive integer, where:
  • each photovoltaic module shutdown device 202 In the shutdown system, the output terminals of each photovoltaic module shutdown device 202 are cascaded, and the input terminals of each photovoltaic module shutdown device 202 are respectively connected to each photovoltaic module 201 in a one-to-one correspondence; after each photovoltaic module shutdown device 202 is cascaded
  • the positive pole is connected to the positive pole of the corresponding DC interface of the inverter 204 through the positive pole 2031 of the DC bus;
  • the negative pole of each photovoltaic module switch 202 after cascading is connected to the negative pole of the corresponding DC interface of the inverter 204 through the negative pole 2032 of the DC bus.
  • the photovoltaic module 201 includes at least one photovoltaic module.
  • the photovoltaic module 201 is regarded as a photovoltaic module. Its structure is shown in Figures 7 and 8.
  • the photovoltaic module 201 includes two photovoltaic modules Its structure is shown in FIG. 9, and the specific structure of the photovoltaic module 201 will not be repeated here one by one, and they are all within the protection scope of the present application.
  • Figure 8 which shows the structure of the photovoltaic system when the number of shutdown systems is 2.
  • Figures 7 and 9 are the structure of the photovoltaic system when the number of shutdown systems is 1. The other structures of the photovoltaic system will not be described here. To repeat them one by one, they are all within the protection scope of this application.
  • the positive output terminal of the first photovoltaic module shut-off device 202 is connected to the positive electrode 2031 of the DC bus; the negative output terminal of the first photovoltaic module shutdown device 202 is connected to the second photovoltaic module shutdown device
  • the output terminal of 202 is connected to the positive pole, and the negative pole of the output terminal of the second photovoltaic module shut-off device 202 is connected to the positive pole of the output terminal of the third photovoltaic module shut-off device 202.
  • the positive pole of the output terminal is connected to the negative pole of the output terminal of the N-1th photovoltaic module shut-off device 202;
  • the photovoltaic module switch-off 202 When the photovoltaic module switch-off 202 is in the on state, the photovoltaic module 201 realizes electric energy output. At this time, the voltage on the DC bus 203 is relatively high; when the photovoltaic module switch-off 202 is in the off state, the photovoltaic module 201 stops the electric energy output. At this time, the voltage on the DC bus 203 is relatively low. When all the photovoltaic module switchers 202 are in the off state, the voltage on the DC bus 203 is within a safe range, usually less than 30V, to avoid overvoltage damage to each device in the photovoltaic system .
  • photovoltaic module shut-off device 202 For the specific working process and structure of the photovoltaic module shut-off device 202, refer to the photovoltaic module shut-off device 202 provided in any of the foregoing embodiments, and will not be repeated here.
  • the start signal generator 205 is used to send a start signal to each photovoltaic module shutoff 202 in the same shutdown system.
  • the start signal is a power line carrier signal, a wireless communication signal or an analog pulse signal.
  • the start signal is a power line carrier signal
  • the start signal complies with the fast shutdown signal specification formulated by the SunSpec Alliance.
  • the start signal generator 205 is integrated in the inverter 204 (as shown in FIGS. 7-9), or is independently placed on the DC bus 203 (not shown).
  • the inverter 204 supplies power to the start signal generator 205; when it is independently placed on the DC bus 203, the start signal generator 205 is powered by other non-photovoltaic power sources, such as AC side grid power supply, or battery power supply in the energy storage system.
  • start signal generator 205 sends a start signal to the photovoltaic module switch-off 202 in the same shutdown system, there may be photovoltaic modules 201 that are blocked and unable to output voltage, causing the photovoltaic module switch-off 202 connected to it to have no auxiliary power supply. Unable to start.
  • the photovoltaic module switch-off 202 can sample its own state parameters through the built-in parameter collection module, and then according to the state parameters and the inverter 204 actively adjust the voltage and current working characteristics of the DC bus 203 to determine whether the inverter 204 is In the working state, and when the inverter 204 is in the working state, the inverter 204 is controlled to be turned on so that the corresponding photovoltaic module 201 realizes electric energy output.
  • the inverter 204 is required to have a fault recovery time.
  • the fault recovery time is usually tens of seconds to several minutes, and the fault recovery time is greater than the fast shutdown time required by the system, such as 30 seconds specified in NEC 2017.
  • the start-up signal generator 205 sends a start-up signal to the photovoltaic module switch-off 202 in the same shutdown system, the photovoltaic modules 201 realize electric energy output one by one.
  • the DC input voltage of the inverter 204 is normal, and the input undervoltage fault disappears, but the reverse The converter 204 still needs to wait for the fault recovery time before it can start working.
  • the photovoltaic module is in an open circuit state.
  • the start signal generator 205 needs to continue to send a start signal to the photovoltaic module switcher 202 in the same shutdown system until the inverter is inverted.
  • the device 204 starts to start.
  • the start-up signal generator 205 continues to send to each photovoltaic module switch-off 202 in the same shutdown system Start the signal until the corresponding inverter 204 enters the normal power generation state.
  • the auxiliary power system of the inverter 204 is powered by other non-photovoltaic power sources, for example, the AC side power grid, or the battery in the energy storage system.
  • the working process of the inverter 204 is: the inverter 204 judges whether the photovoltaic system is ready, for example, whether the grid voltage is normal, the grid frequency is normal, the impedance to the ground is normal, whether it is shut down by remote control, whether it is manually pressed quickly Turn off the button, etc.; after the inverter 204 detects that the system is ready, it commands the start signal generator 205 to send a start signal to each photovoltaic module switcher 202 in the same shutdown system; each photovoltaic module switcher 202 starts After that, the inverter 204 starts to output power and inverts the energy of the photovoltaic components to the grid; when the inverter 204 detects an abnormality in the system, it stops power output, which also ends the maximum power point tracking process of the DC bus 203.
  • the inverter 204 continuously adjusts the voltage and current of the DC bus 203 for maximum power point tracking, and the inverter 204 can also actively adjust the voltage and current of the DC bus 203, especially the inverter When the inverter 204 is working in a constant power state, it actively adjusts the voltage and current of the DC bus 203, which can continuously change the state parameters of the photovoltaic module shut-off device and prevent the photovoltaic module shut-off device from being turned off by mistake. It should be noted that when the photovoltaic system includes multiple DC buses, the inverter 204 can implement the function of actively adjusting the voltage and current for each DC bus connected to it. Within the scope of protection applied for.
  • the inverter 204 and the photovoltaic module shutdown device 202 are used to implement the fast shutdown method provided in the foregoing embodiment. For details, refer to the foregoing embodiment, and will not be repeated here.
  • the output characteristics of each photovoltaic module continue to fluctuate due to the maximum power point tracking of the inverter 204 during normal operation to determine whether the photovoltaic system is present. Failure to avoid the need to continuously send heartbeat signals or analog pulses with similar functions for judgment, which reduces the software resources and power consumption of the system.

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Abstract

提供了一种快速关断方法、光伏组件关断器和光伏系统，快速关断方法包括：光伏组件关断器在接收启动信号后，控制自身开通使所连接的光伏组件实现电能输出；然后即可通过检测自身的状态参数，来判断光伏系统中对应逆变器通道是否出现故障；若光伏系统中对应逆变器通道出现故障，则控制自身关断，使自身所连接的光伏组件停止电能输出；而若光伏系统中对应逆变器通道未出现故障，则一直维持自身开通；从而无需中央控制器持续发送信号或脉冲来控制光伏组件关断器开通。

Description

一种快速关断方法、光伏组件关断器和光伏系统
本申请要求于2020年04月16日提交中国专利局、申请号为202010297765.1、发明名称为“一种快速关断方法、光伏组件关断器和光伏系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明属于光伏并网发电技术领域，更具体的说，尤其涉及一种快速关断方法、光伏组件关断器和光伏系统。
背景技术
光伏发电技术作为一种可再生能源发电技术，得到广泛应用，光伏阵列输出直流电，经逆变器变换成交流电后传输至电网。而串联光伏阵列的电压很高，为了提高光伏系统的安全性，要求光伏系统能够快速关断；现有技术中一般为光伏组件设置关断器，以通过关断器自身的通断来使光伏组件实现电能输出与否。
现有技术中，系统的中央控制器需要持续发送心跳通讯信号或周期性激励脉冲源，来维持各个关断器处于开通状态。而持续发送的心跳通讯信号或周期性激励脉冲源，会导致中央控制器的软件资源占用较大，同时电力损耗也较大。
发明内容
有鉴于此，本发明的目的在于提供一种快速关断方法、光伏组件关断器和光伏系统，用于降低中央控制器的软件资源占用和电力损耗。
本发明第一方面公开了一种快速关断方法，包括：
光伏系统中的光伏组件关断器接收启动信号；
所述光伏组件关断器控制自身开通，使自身所连接的光伏组件实现电能输出；
所述光伏组件关断器检测自身的状态参数，判断光伏系统中对应逆变器通道是否出现故障；
若对应逆变器通道出现故障，则所述光伏组件关断器控制自身关断，使自身所连接的光伏组件停止电能输出；
若对应逆变器通道未出现故障，则所述光伏组件关断器维持自身开通。
可选的，所述光伏组件关断器判断所述光伏系统中对应逆变器通道是否出 现故障，包括：
所述光伏组件关断器判断自身的状态参数是否处于动态变化中；
若自身的状态参数未处于动态变化中，则所述光伏组件关断器判定对应逆变器通道出现故障；
若自身的状态参数处于动态变化中，则所述光伏组件关断器判定对应逆变器通道未出现故障。
可选的，所述光伏组件关断器判断所述光伏系统中对应逆变器通道是否出现故障，包括：
所述光伏组件关断器依据所述状态参数，判断对应直流总线上是否出现拉弧；
若对应直流总线上出现拉弧，则所述光伏组件关断器判定对应逆变器通道出现故障；
若对应直流总线上未出现拉弧，则所述光伏组件关断器判定对应逆变器通道未出现故障。
可选的，所述光伏系统中光伏组件关断器接收启动信号，包括：
所述光伏组件关断器在自身启动时间段或者逆变器故障恢复等待时间段内接收所述启动信号。
可选的，若所述启动信号为在自身启动时间段内接收到的，则在所述光伏组件关断器控制自身开通之前，还包括：
所述光伏组件关断器有辅助供电后，检测自身的输出电流，判断所述光伏系统中的逆变器是否处于工作状态；
若所述逆变器处于工作状态且接收到启动信号，则执行所述光伏组件关断器控制自身开通的步骤。
可选的，所述光伏组件关断器控制自身关断，使自身所连接的光伏组件停止电能输出之前，还包括：
所述光伏组件关断器判断对应逆变器通道持续出现故障的时间是否长达预设时间；
若所述对应逆变器通道持续出现故障的时间长达预设时间，则执行所述光伏组件关断器控制自身关断，使自身所连接的光伏组件停止电能输出的步骤。
可选的，所述预设时间大于所述光伏系统中的逆变器最大功率点跟踪的步长时间，且小于所述光伏系统快速关断的要求时间。
可选的，还包括：
所述光伏系统中的逆变器对所述光伏系统中的直流总线施加电压扰动，以改变所述光伏组件关断器的状态参数、避免所述光伏组件关断器误关断。
本发明第二方面公开了一种光伏组件关断器，包括：开关单元、旁路二极管、驱动单元、参数采集模块、处理器和启动信号接收单元；其中：
所述参数采集模块，用于采集光伏组件关断器的状态参数，并将采集到的所述状态参数输出至所述处理器；
所述启动信号接收单元，用于接收启动信号，并将所述启动信号输出至所述处理器；
所述开关单元，设置于所述光伏组件关断器的正极支路或者负极支路上，用于根据所述处理器的控制，实现所述光伏组件关断器的开通或关断；
所述旁路二极管，用于在所述光伏组件关断器关断时实现所述光伏组件关断器的旁路功能；
所述处理器的输出端通过所述驱动单元与所述开关单元的控制端相连；所述处理器用于结合所述启动信号接收单元、所述参数采集模块、所述驱动单元以及所述开关单元，使所述光伏组件关断器能够实现本发明第一方面公开的相应快速关断方法。
可选的，所述参数采集模块包括：电压采样单元和至少一个电流采样单元；
所述电压采样单元，用于采集所述光伏组件关断器的输入电压，并将采集到的所述输入电压输出至所述处理器；
所述电流采样单元，用于采集所述光伏组件关断器的输入电流/输出电流，并将采集到的输入电流/输出电流输出至所述处理器。
可选的，所述启动信号接收单元设置于所述光伏组件关断器的负极支路上、所述旁路二极管的阳极与所述光伏组件关断器的输出端负极之间；
若所述电流采样单元的个数为一个，则所述电流采样单元设置于所述光伏组件关断器的正极支路上、所述旁路二极管的阴极与所述光伏组件关断器的输出端正极之间；或者，所述电流采样单元设置于所述光伏组件关断器的负极支 路上、所述旁路二极管的阳极与所述启动信号接收单元之间；
若所述电流采样单元的个数为两个，分别为第一电流采样单元和第二电流采样单元，则所述第一电流采样单元设置于所述光伏组件关断器的负极支路上、所述光伏组件关断器的输入端负极与所述启动信号接收单元之间，所述第二电流采样单元设置于所述第一电流采样单元和所述启动信号接收单元的连接点与所述旁路二极管的阳极之间。
本发明第三方面公开了一种光伏系统，包括：至少一个关断系统和至少一个逆变器，所述关断系统包括：直流总线、启动信号发生器、N个光伏模块和N个如本发明第二方面公开的的光伏组件关断器，N为正整数，其中：
所述关断系统中，各个所述光伏组件关断器的输出端级联，各个光伏组件关断器的输入端分别与各个光伏模块一一对应相连；各个所述光伏组件关断器级联后的正极通过所述直流总线正极与所述逆变器的对应直流接口正极相连；各个所述光伏组件关断器级联后的负极通过所述直流总线负极与所述逆变器的对应直流接口负极相连；
所述启动信号发生器，用于发送启动信号至同一所述关断系统中各个所述光伏组件关断器。
可选的，所述启动信号发生器用于发送启动信号至同一所述关断系统中各个所述光伏组件关断器时，具体用于：
在同一所述关断系统中各个所述组件关断器的启动过程或所述逆变器的故障恢复过程时，向同一所述关断系统中各个所述光伏组件关断器持续发送所述启动信号，直至对应逆变器进入正常发电状态。
可选的，所述逆变器还用于对各个所述直流总线施加电压扰动，以改变所述光伏组件关断器的状态参数、避免所述光伏组件关断器误关断。
可选的，所述启动信号为电力线载波信号、无线通讯信号或模拟脉冲信号。
可选的，当所述启动信号为电力线载波信号时，所述启动信号符合SunSpec联盟制定的快速关断信号规范。
可选的，所述启动信号发生器集成于所述逆变器中，或者，独立置于所述直流总线上。
从上述技术方案可知，本发明提供的一种快速关断方法，光伏组件关断器 在接收启动信号后，控制自身开通使所连接的光伏组件实现电能输出；然后即可通过检测自身的状态参数，来判断光伏系统中对应逆变器通道是否出现故障；若光伏系统中对应逆变器通道出现故障，则控制自身关断，使自身所连接的光伏组件停止电能输出；而若光伏系统中对应逆变器通道未出现故障，则一直维持自身开通；从而无需中央控制器持续发送信号或脉冲来控制光伏组件关断器开通，降低了中央控制器的软件资源占用和电力损耗。
附图说明
图1是本发明实施例提供的一种快速关断方法的流程图；
图2是本发明实施例提供的另一种快速关断方法的流程图；
图3是本发明实施例提供的另一种快速关断方法的流程图；
图4是本发明实施例提供的一种光伏组件关断器的示意图；
图5是本发明实施例提供的另一种光伏组件关断器的示意图；
图6是本发明实施例提供的另一种光伏组件关断器的示意图；
图7是本发明实施例提供的一种光伏系统的示意图；
图8是本发明实施例提供的另一种光伏系统的示意图；
图9是本发明实施例提供的另一种光伏系统的示意图；
图10是本发明实施提供的光伏组件的典型电压电流曲线图；
图11是本发明实施例提供的另一种光伏组件关断器的示意图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
在本申请中，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、物品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括所述要素的过程、方法、物品或者设备中还存在另外的相同要素。
本发明实施例提供了一种快速关断方法，以解决现有技术中系统的中央控制器需要持续发送心跳通讯信号或周期性激励脉冲源来维持各个关断器处于开通状态，而导致中央控制器的软件资源占用较大，同时电力损耗也较大的问题。
该快速关断方法，参见图1，包括：
S101、光伏系统中的光伏组件关断器接收启动信号。
需要说明的是，光伏组件关断器的外部设备如启动信号发生器产生并发送的，该启动信号可以是电力线载波信号、无线通讯信号或模拟脉冲信号；在此不做具体限定，均在本申请的保护范围内。
在实际应用中，需要说明的是，SunSpec联盟是一个由100多个太阳能和存储分布式能源行业参与者组成的贸易联盟；SunSpec联盟设定的SunSpec规范适用于大多数太阳能光伏系统元件，并在全球范围内得到采用，SunSpec规范中为快速关断设备规定了统一的电力线载波通讯信号。因此，当该启动信号为电力载波信号时，该启动信号符合SunSpec联盟制定的快速关断信号规范，加强了电路的兼容性。
在实际应用中，在光伏组件关断器启动时间段或者逆变器故障恢复等待时间段内，该光伏组件关断器接收启动信号，也即，对应的启动信号产生并发送的设备如启动信号发生器，在光伏组件关断器启动时间段或者逆变器故障恢复等待时间段内发送启动信号。
需要说明的是，光伏组件关断器接收到启动信号，说明该光伏组件关断器所连接的逆变器允许该光伏组件关断器进入工作状态，即执行步骤S102。
在实际应用中，光伏系统中可能存在受遮挡而无法输出电压的光伏组件，导致所连接的的组件关断器没有辅助供电。然而，若启动信号为在光伏组件关断器启动时间段内且自身无辅助供电接收到的，则此时光伏组件关断没有辅助供电、无法启动，也即无法控制自身开通，需等待自身有辅助供电后，再执行步骤S102；另外，该启动信号可能不会被持续发送。因此，若启动信号为在光伏组件关断器启动时间段内且自身无辅助供电时接收到的，则在接收启动信号且自身恢复辅助供电后，检测自身的输出电流，判断光伏系统中的逆变器是否处于工作状态；若逆变器处于工作状态，则执行步骤S102。
S102、光伏组件关断器控制自身开通，使自身所连接的光伏组件实现电能输出。
需要说明的是，光伏组件关断器开通与实现通信功能不同；光伏组件关断器开通是指自身内部的连接开通，以使所连接的光伏组件实现电能输出，而在光伏组件关断器上电即有辅助供电时，光伏组件关断器即可实现通信功能。
在光伏组件关断器开通之后，该光伏组件关断器将有状态参数，即输入输出参数，此时执行步骤S103。
S103、光伏组件关断器检测自身的状态参数，判断光伏系统中对应逆变器通道是否出现故障。
该状态参数可以是：输入参数，如输入电压(即相应光伏组件的输出电压)和输入电流(即相应光伏组件的输出电流)；也可以是：输出参数，如输出电流和输出电压。
需要说明的是，逆变器通道存在的故障有逆变器相应直流接口短路故障、直流总线短路故障和直流总线拉弧故障，若存在上述任一种故障，则该逆变器均无法正常工作，存在电路安全的风险。
因此，若对应逆变器通道出现故障，则需要使光伏组件停止电能输出，即执行步骤S104；而若对应逆变器通道未出现故障，则可继续使光伏组件实现电能输出，即执行步骤S105。
S104、光伏组件关断器控制自身关断，使自身所连接的光伏组件停止电能输出。
S105、光伏组件关断器维持自身开通。
在本实施例中，光伏组件关断器接收启动信号之后即可进入开通状态，而后通过光伏组件关断器检测并判断自身的状态参数即可决定自身是否维持开通状态，无需中央控制器持续发送信号或脉冲来控制光伏组件关断器开通，在光伏组件关断器开通之后也不再需要启动信号，降低了中央控制器的软件资源占用和电力损耗。
需要说明的是，在某些场合中要求逆变器有一段故障恢复时间，故障恢复时间通常为几十秒至几分钟，故障恢复时间大于系统要求的快速关断时间，例如NEC 2017中规定的30秒。在光伏系统中的光伏组件逐个实现电能输出后， 光伏系统中的逆变器的直流输入电压正常，输入欠压故障消失，但逆变器还需要等待故障恢复时间后才能开始工作。在故障恢复等待期间光伏组件处于开路状态，为了维持逆变器的直流输入电压正常，在故障恢复等待期间启动信号发生器需要向光伏组件关断器持续发送启动信号，也即组件关断器持续接收到启动信号。
因此，在实际应用中，在步骤S104之前，还包括：光伏组件关断器判断对应逆变器通道持续出现故障的时间是否长达预设时间即上述故障恢复时间。若对应逆变器通道持续出现故障的时间长达预设时间，则执行步骤S104、光伏组件关断器控制自身关断，使自身所连接的光伏组件停止电能输出。该预设时间，即上述故障恢复时间，大于光伏系统中的逆变器最大功率点跟踪的步长时间，且小于光伏系统快速关断的要求时间。
需要说明的是，导致逆变器通道故障的原因不同，相应的，上述步骤S103所涉及的判断光伏系统中对应逆变器通道是否出现故障的具体过程不同，具体的：
(1)在实际应用中，在检测逆变器通道故障中的直流总线短路和逆变器相应直流接口短路时，上述步骤S103所涉及的判断光伏系统中对应逆变器通道是否出现故障，参见图2，包括：
S201、光伏组件关断器判断自身的状态参数是否处于动态变化中。
具体的，若状态参数为输入电流和输入电压，则分别判断输入电流和输入电压是否均处于动态变化中。若状态参数为输出电流和输出电压，则判断输出电流和输出电压是否处于动态变化中。
需要说明的是，是否处于动态变化可以是通过前一次采样值与当前采样值进行比较得到；例如，若前一次采样值与当前采样值不一致，则判定处于动态变化中，若前一次采样值与当前采样值一致，则判定不处于动态变化中。也可以是判断前一次采样值与当前采样值连续一致的次数是否大于等于预设值，若前一次采样值与当前采样值连续一致的次数大于等于预设值，则判定不处于动态变化中，若前一次采样值与当前采样值连续一致的次数小于预设值，则判定 处于动态变化中。
在此，不对步骤201的具体实现方式进行限定，视实际情况而定即可，均在本申请的保护范围内。上述状态参数也不仅限于输入电流、输入电压、输出电流和输出电压，能够表征光伏组件关断器输出参数/输出参数的其他参数，均在本申请的保护范围内。
需要说明的是，光伏系统中的逆变器会动态调节光伏系统中直流总线的电压和电流来进行最大功率点跟踪，使得直流总线对应的各个光伏组件的输出功率最大。因此，在逆变器通道未出现故障的情况下，直流总线的电压和电流会动态变化，相应的，对应光伏组件关断器的状态参数也会动态变化；也即，由于最大功率点跟踪的原因会导致每块光伏组件的输出特性持续波动，这一波动是逆变器正常工作时的固有特性；光伏组件关断器利用这一固有特性即可进行故障判断。另外，为了避免光伏组件关断器误关断，逆变器在恒定功率下即不进行最大功率点跟踪时，也可以主动调节直流总线的电压和电流，使各光伏组件关断器的状态参数处于动态变化中。进而，若光伏组件关断器判断出自身的状态参数未处于动态变化中，则说明逆变器通道当前的状态不符合正常的工作特性，即可判定对应逆变器通道出现故障、执行步骤S104；而若光伏组件关断器判断出自身的状态参数处于动态变化中，则说明逆变器通道当前的状态符合正常的工作特性，即可判定对应逆变器通道未出现故障、执行步骤S105。
(2)在实际应用中，在检测逆变器通道故障中的直流总线拉弧时，上述步骤S103所涉及的判断光伏系统中对应逆变器通道是否出现故障，参见图3，包括：
S301、光伏组件关断器依据状态参数，判断对应直流总线上是否出现拉弧。
光伏组件关断器依据自身输入参数(即光伏组件输出电压和输出电流)，判断是否出现直流拉弧故障。具体的，主要是通过电流噪声大小来判断对应直流总线上是否出现拉弧，即直流电弧故障，如电流噪声大于对应预设值，则判定对应直流总线上出现拉弧，即存在直流电弧故障，电流噪声小于等于对应预设值则判定对应直流总线上未出现拉弧，即不存在直流电弧故障。
若对应直流总线上出现拉弧，则判定对应逆变器通道出现故障、执行步骤 S104；而若对应直流总线上未出现拉弧，则判定对应逆变器通道未出现故障、执行步骤S105。
需要说明的是，在光伏系统运行过程中，直流拉弧会导致接触部分温度急剧升高，持续的电弧会产生3000-7000℃的高温，并伴随着高温碳化周围器件，轻者熔断保险、线缆，重者烧毁组件和设备引起火灾。当逆变器不具备电弧故障分断器或电弧故障分断器未能发挥作用时，光伏系统会出现重大安全问题。
而本实施例中，通过光伏组件关断器的状态参数，判断对应直流总线上是否出现拉弧，进而在对应直流总线上出现拉弧时，控制自身关断、使光伏组件停止电能输出，进而避免了逆变器不具备电弧故障分断器或电弧故障分断器未能发挥作用时，光伏系统会出现重大安全问题。
需要说明的是，上述步骤S201和步骤S301可以独立实现，也可以是组合实现，视实际情况而定即可，均在本申请的保护范围内。
在上述任一实施例的基础之上，参见图11(以图1的基础为例进行展示)，还可以包括：S401、光伏系统中的逆变器对光伏系统中的直流总线施加电压扰动，以改变光伏组件关断器的状态参数、避免光伏组件关断器误关断。
在逆变器工作期间持续调节光伏系统中各个直流总线的电压和电流进行最大功率点追踪。
如图10所示，其示出了光伏组件的输出电压和输出电流的曲线特性。典型的工作点包括开路工况点、短路工况点和最大功率点。在开路工况点处，光伏组件的输出电压最高，为开路电压，输出电流为零，输出功率为零；在短路工况点处，光伏组件的输出电压为零，输出电流最大，为短路电流，输出功率为零；在最大功率点处，光伏组件的输出电压为最大功率点电压，输出电流为最大功率点电流，输出功率最大。
逆变器会动态调节直流总线的电压和电流进行最大功率点跟踪，使得直流总线对应的各个光伏组件的输出功率最大。常用的最大功率点跟踪方法为爬山法；具体的，逆变器主动对直流总线上的电压施加扰动，使得电压升高或降低， 根据扰动后的电压和功率的变化判断最大功率点的位置，控制直流总线的输出工况趋向于最大功率点处。受逆变器最大功率点跟踪的影响，光伏组件的输出电压电流特性是动态变化的，光伏组件处于稳定时，其功率在最大功率点左右波动，如在M点至N点的范围内波动。
在逆变器电网侧故障或人为控制逆变器停机时，光伏组件处于开路电压状态；在逆变器输入端短路故障时，光伏组件处于短路电流状态；在直流总线上存在一个短路电阻时，光伏组件的输出状态处于某个固定的电压电流工况点。在上述任意一种情况中，光伏组件关断器利用自身的状态参数即逆变器正常工作时固有的输出特性，来检测到系统中出现故障，并在检测到故障后，断开对应的光伏组件。
需要说明的是，在某些场合中逆变器需要工作在恒定功率状态，即逆变器不进行最大功率点跟踪，使得直流总线的电压和电流状态几乎没有变化。此时，为了防止光伏组件关断器误判断，逆变器可以故意对直流总线施加短暂的电压扰动，以使直流总线的电压和电流波动，进而光伏组件关断器维持开通。在光照强度较弱时，光伏组件的输出电流较低，光伏组件关断器中的电流采样模块可能受精度和偏置的影响，采样得到的电流不准确。此时，为了防止光伏组件关断器误判断，在光伏组件功率较低时，逆变器也可以对直流总线施加短暂的电压扰动。施加电压扰动的实现方式包括逆变器突然增大输出功率，导致直流总线上的电压跌落；或者，突然降低输出功率，导致直流总线上的电压升高。另外，上述功率变化的时间较短，不会对逆变器的平均输出功率有明显影响。
在本实施中，通过逆变器对光伏系统中直流总线施加电压扰动，即便逆变器工作在恒定功率状态，即逆变器不进行最大功率点跟踪，也仍对直流总线施加电压扰动，以改变光伏组件关断器的状态参数、避免光伏组件关断器因逆变器工作作在恒定功率状态而误关断，提高温升降额的诊断精度。
本发明实施例提供了一种光伏组件关断器，参见图4，包括：开关单元401、旁路二极管404、驱动单元403、参数采集模块(如图4所示的电压采样单元402和电流采样单元406)、处理器405和启动信号接收单元407；其中：
参数采集模块，用于采集光伏组件关断器的状态参数，并将采集到的状态参数输出至处理器405。
启动信号接收单元407设置于该光伏组件关断器的负极支路上、旁路二极管404的阳极与光伏组件关断器的输出端负极Uout-之间；具体的，启动信号接收单元407的输入端正极与光伏组件关断器的输出端负极Uout-相连，启动信号接收单元407的输入端负极直接或通过参数采集模块与光伏组件关断器的输入端负极Uin-相连；启动信号接收单元407用于接收启动信号，并将启动信号输出至处理器405。
开关单元401设置于负极支路上(未进行图示)；或者，开关单元401设置于光伏组件关断器的正极支路，具体的，如图4所示，开关单元401的输入端与光伏组件关断器的输入端正极Uin+相连，开关单元401的输出端与旁路二极管404的阴极相连，连接点直接或通过参数采集模块与光伏组件关断器的输出端正极Uout+相连。开关单元401用于受处理器405控制开通或关闭，以使光伏组件关断器自身的连接开通或关断。
其中，上述开关单元401为半导体开关器件，也即，上述开关单元401可以是IGBT(Insulated Gate Bipolar Transistor，绝缘栅双极晶体管)，也可以是MOSFET(Metal-Oxide-Semiconductor Field-Effect Transistor，金属氧化物半导体场效应晶体管)。开关单元401可以由多个半导体开关器件串联或并联组合而成，在此不再一一赘述，均在本申请的保护范围内。
旁路二极管404的阳极直接或通过参数采集模块与启动信号接收单元407的输入端负极相连；旁路二极管404用于在光伏组件关断器关断即开关单元401关断时实现光伏组件官关断器的旁路功能。
参数采集模块的输出端和启动信号接收单元407的输出端均与处理器405的对应输入端相连；处理器405的输出端通过驱动单元403与开关单元401的控制端相连。
光伏组件关断器，用于上述任一实施例提供的快速关断方法，详情参见上述实施例，在此不再一一赘述。
在本实施例中，通过参数采集模块，采集光伏组件关断器的状态参数，并通过处理器405判断光伏系统中对应逆变器通道是否出现故障；并依据判断结 果控制开关单元401执行相应动作，避免了进而避免需要持续发送心跳信号，或类似功能的模拟脉冲来判断，降低了系统的软件资源和功耗。
在实际应用中，该参数采集模块包括：电压采样单元402和至少一个电流采样单元(如图4和图5所示的406，如图6所示的406a和406b)。
电压采样单元402的输入端正负极分别与光伏组件关断器的输入端正负极相连，电压采样单元402的输出端与处理器405相连；电压采样单元402用于采集光伏组件关断器的输入电压，并将采集到的输入电压输出至处理器405。
电流采样单元，用于采集光伏组件关断器的输入电流/输出电流，并将采集到的输入电流/输出电流输出至处理器405。在实际应用中，电流采样单元的个数可以是一个，也可以是两个，下面分别对包括一个电流采样单元和两个电流采样单元这两种情况进行说明，具体的：
(1)若电流采样单元的个数为1，则如图5所示，电流采样单元406设置于光伏组件关断器的正极支路上、旁路二极管404的阴极与光伏组件关断器的输出端正极Uout+之间；具体的电流采样单元406的输出端与处理器405相连；电流采样单元406的一端分别与开关单元401的输出端和旁路二极管404的阴极相连，电流采样单元406的另一端与光伏组件关断器的输出端正极Uout+相连。或者，如图4所示，电流采样单元406设置于光伏组件关断器的负极支路上、旁路二极管404的阳极与启动信号接收单元407之间；具体的，电流采样单元406的一端与启动信号接收单元407的输入端负极相连，电流采样单元406的另一端分别与旁路二极管404的阳极和光伏组件关断器的输入端负极Uin-相连。
当开关单元401开通时，旁路二极管404截止，电流采样单元406采样到的电流为光伏组件的输出电流，即光伏组件关断器的输入电流；当开关单元401关断时，电流采样单元406采样到的电流为旁路二极管404的电流，即光伏组件关断器的输出电流。
(2)若电流采样单元的个数为2，则如图6所示，第一电流采样单元406a设置于光伏组件关断器的负极支路上、光伏组件关断器的输入端负极Uin-与启 动信号接收单元407之间，第二电流采样单元406b设置于第一电流采样单元406a和启动信号接收单元407的连接点与旁路二极管404的阳极之间；具体的，第一电流采样单元406a的输出端和第二电流采样单元406b的输出端均与处理器405相连；第二电流采样单元406b的一端与旁路二极管404的阳极相连；第二电流采样单元406b的另一端分别与第一电流采样单元406a的一端和启动信号接收单元407的输入端负极相连；第一电流采样单元406a的另一端与光伏组件关断器的输入端负极Uin-相连。
第一电流采样单元406a用于采样光伏组件的输出电流，即光伏组件关断器的输入电流，第二电流采样单元406b用于采样旁路二极管404的电流，即光伏组件关断器的输出电流。
上述电流采集单元可以为电流传感器，也可以是其他能够采集电流的器件，在此不再一一赘述，均在本申请的保护范围内。
在本实施例中，通过电压采样模块和电流采样模块，可以进行光伏组件端的直流拉弧检测，该光伏组件端的直流拉弧检测可以检测到系统中出现的并联型拉弧故障。
本发明实施例提供了一种光伏系统，参加图7(图7以一个关断系统为例进行展示)，包括：至少一个关断系统和至少一个逆变器204，关断系统包括：直流总线203、启动信号发生器205、N个光伏模块201和N个光伏组件关断器202，N为正整数，其中：
关断系统中，各个光伏组件关断器202的输出端级联，各个光伏组件关断器202的输入端分别与各个光伏模块201一一对应相连；各个光伏组件关断器202级联后的正极通过直流总线正极2031与逆变器204的对应直流接口正极相连；各个光伏组件关断器202级联后的负极通过直流总线负极2032与逆变器204的对应直流接口负极相连。
该光伏模块201包括至少一个光伏组件，在光伏模块201包括一个光伏组件时，将光伏模块201视为光伏组件，其结构如图7和图8所示，在光伏模块201包括两个光伏组件时，其结构如图9所示，光伏模块201的具体结构在此不再一一赘述，均在本申请的保护范围内。参见图8，其示出了关断系统个数 为2时光伏系统的结构，图7和图9均为关断系统个数为1时光伏系统的结构，光伏系统的其他结构在此不再一一赘述，均在本申请的保护范围内。
具体的，关断系统中，第1个光伏组件关断器202的输出端正极与直流总线正极2031相连；第1个光伏组件关断器202的输出端负极与第2个光伏组件关断器202的输出端正极相连，第2个光伏组件关断器202的输出端负极与第3个光伏组件关断器202的输出端正极相连，以此类推，第N个光伏组件关断器202的输出端正极与第N-1个光伏组件关断器202的输出端负极相连；第N个光伏组件关断器202的输出端负极与直流总线负极2032相连。
光伏组件关断器202处于开通状态下，使光伏模块201实现电能输出，此时直流总线203上的电压较高；光伏组件关断器202处于关断状态下，使光伏模块201停止电能输出，此时直流总线203上的电压较低，当所有光伏组件关断器202均处于关断状态时，直流总线203上的电压处于安全范围内，通常小于30V，避免光伏系统中各个器件过压损坏。
该光伏组件关断器202的具体工作过程及结构参见上述任一实施例提供的光伏组件关断器202，在此不再一一赘述。
启动信号发生器205，用于发送启动信号至同一关断系统中各个光伏组件关断器202。
在实际应用中，该启动信号为电力线载波信号、无线通讯信号或模拟脉冲信号。当启动信号为电力线载波信号时，启动信号符合SunSpec联盟制定的快速关断信号规范。
启动信号发生器205集成于逆变器204中(如图7-图9所示)，或者，独立置于直流总线203上(未进行图示)。当启动信号发生器205集成在逆变器204中时，逆变器204向启动信号发生器205供电；当独立置于直流总线203上时，启动信号发生器205由其他非光伏电源供电，例如交流侧电网供电，或者在储能系统中由电池供电。
在启动信号发生器205向同一关断系统中的光伏组件关断器202发送启动信号时，可能存在受遮挡无法输出电压的光伏模块201，导致其所连接的光伏组件关断器202没有辅助供电无法启动，此时需等到该光伏模块201恢复电能输出，即光伏组件关断器202有辅助供电启动后，再执行相应的开通动作；但 由于启动信号发生器205不会持续发送启动信号，因此，光伏组件关断器202可以通过内置的参数采集模块采样自身的状态参数，再依据该状态参数和逆变器204主动调节直流总线203的电压和电流的工作特性，来判断逆变器204是否处于工作状态，并在逆变器204处于工作状态时，控制自身开通、使对应的光伏模块201实现电能输出。
在某些场合中要求逆变器204有一段故障恢复时间，故障恢复时间通常为几十秒至几分钟，故障恢复时间大于系统要求的快速关断时间，例如NEC 2017中规定的30秒。在启动信号发生器205向同一关断系统中的光伏组件关断器202发送启动信号后，光伏模块201逐个实现电能输出，逆变器204的直流输入电压正常，输入欠压故障消失，但逆变器204仍需要等待故障恢复时间后才能开始工作。在故障恢复等待期间光伏组件处于开路状态，为了维持直流输入电压正常，在故障恢复等待期间启动信号发生器205需要向同一关断系统中的光伏组件关断器202持续发送启动信号，直到逆变器204开始启动。
具体的，在同一关断系统中各个光伏组件关断器202的启动过程或逆变器204的故障恢复过程时，启动信号发生器205向同一关断系统中各个光伏组件关断器202持续发送启动信号，直至对应逆变器204进入正常发电状态。
逆变器204的辅助电源系统由其他非光伏电源供电，例如交流侧电网供电，或者由储能系统中电池供电。
逆变器204的工作过程为：逆变器204判断光伏系统是否准备就绪，例如，电网电压是否正常、电网频率是否正常、对地阻抗是否正常、是否被远程控制停机、是否被人为按下快速关断按键等；逆变器204在检测到系统准备就绪后，命令启动信号发生器205发送启动信号给处于同一关断系统中的各个光伏组件关断器202；各个光伏组件关断器202启动后，逆变器204开始输出功率，将光伏组件的能量逆变到电网上；当逆变器204检测到系统异常后停止功率输出，也结束了直流总线203的最大功率点跟踪过程。需要说明的是，在工作期间的逆变器204持续调节直流总线203的电压和电流进行最大功率点追踪，并且，逆变器204也可以主动调节直流总线203的电压和电流，尤其是逆变器204工作在恒定功率状态时，主动调节直流总线203的电压和电流，可以持续改变光伏组 件关断器的状态参数、避免光伏组件关断器误关断。需要说明的是，在光伏系统包括多个直流总线时，逆变器204对各个与其有连接关系的直流总线均能够实现主动调节电压和电流的功能，在此不再一一赘述，均在本申请的保护范围内。
逆变器204和光伏组件关断器202用于执行上述实施例提供的快速关断方法，详情参见上述实施例，在此不再一一赘述。
在本实施例中，光伏组件关断器202启动后，通过逆变器204正常工作时最大功率点跟踪的原因导致每块光伏组件的输出特性持续波动这一固有特性，来判断光伏系统是否出现故障，进而避免需要持续发送心跳信号，或类似功能的模拟脉冲来判断，降低了系统的软件资源和功耗。
本说明书中的各个实施例均采用递进的方式描述，各个实施例之间相同相似的部分互相参见即可，每个实施例重点说明的都是与其他实施例的不同之处。尤其，对于系统或系统实施例而言，由于其基本相似于方法实施例，所以描述得比较简单，相关之处参见方法实施例的部分说明即可。以上所描述的系统及系统实施例仅仅是示意性的，其中所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部模块来实现本实施例方案的目的。本领域普通技术人员在不付出创造性劳动的情况下，即可以理解并实施。
专业人员还可以进一步意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、计算机软件或者二者的结合来实现，为了清楚地说明硬件和软件的可互换性，在上述说明中已经按照功能一般性地描述了各示例的组成及步骤。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本发明的范围。
对所公开的实施例的上述说明，使本领域专业技术人员能够实现或使用本发明。对这些实施例的多种修改对本领域的专业技术人员来说将是显而易见 的，本文中所定义的一般原理可以在不脱离本发明的精神或范围的情况下，在其它实施例中实现。因此，本发明将不会被限制于本文所示的这些实施例，而是要符合与本文所公开的原理和新颖特点相一致的最宽的范围。

Claims (17)

  1. 一种快速关断方法，其特征在于，包括：
    光伏系统中的光伏组件关断器接收启动信号；
    所述光伏组件关断器控制自身开通，使自身所连接的光伏组件实现电能输出；
    所述光伏组件关断器检测自身的状态参数，判断光伏系统中对应逆变器通道是否出现故障；
    若对应逆变器通道出现故障，则所述光伏组件关断器控制自身关断，使自身所连接的光伏组件停止电能输出；
    若对应逆变器通道未出现故障，则所述光伏组件关断器维持自身开通。
  2. 根据权利要求1所述的快速关断方法，其特征在于，所述光伏组件关断器判断所述光伏系统中对应逆变器通道是否出现故障，包括：
    所述光伏组件关断器判断自身的状态参数是否处于动态变化中；
    若自身的状态参数未处于动态变化中，则所述光伏组件关断器判定对应逆变器通道出现故障；
    若自身的状态参数处于动态变化中，则所述光伏组件关断器判定对应逆变器通道未出现故障。
  3. 根据权利要求1所述的快速关断方法，其特征在于，所述光伏组件关断器判断所述光伏系统中对应逆变器通道是否出现故障，包括：
    所述光伏组件关断器依据所述状态参数，判断对应直流总线上是否出现拉弧；
    若对应直流总线上出现拉弧，则所述光伏组件关断器判定对应逆变器通道出现故障；
    若对应直流总线上未出现拉弧，则所述光伏组件关断器判定对应逆变器通道未出现故障。
  4. 根据权利要求1所述的快速关断方法，其特征在于，所述光伏系统中光伏组件关断器接收启动信号，包括：
    所述光伏组件关断器在自身启动时间段或者逆变器故障恢复等待时间段 内接收所述启动信号。
  5. 根据权利要求4所述的快速关断方法，其特征在于，若所述启动信号为在自身启动时间段内接收到的，则在所述光伏组件关断器控制自身开通之前，还包括：
    所述光伏组件关断器有辅助供电后，检测自身的输出电流，判断所述光伏系统中的逆变器是否处于工作状态；
    若所述逆变器处于工作状态且接收到启动信号，则执行所述光伏组件关断器控制自身开通的步骤。
  6. 根据权利要求1所述的快速关断方法，其特征在于，所述光伏组件关断器控制自身关断，使自身所连接的光伏组件停止电能输出之前，还包括：
    所述光伏组件关断器判断对应逆变器通道持续出现故障的时间是否长达预设时间；
    若所述对应逆变器通道持续出现故障的时间长达预设时间，则执行所述光伏组件关断器控制自身关断，使自身所连接的光伏组件停止电能输出的步骤。
  7. 根据权利要求6所述的快速关断方法，其特征在于，所述预设时间大于所述光伏系统中的逆变器最大功率点跟踪的步长时间，且小于所述光伏系统快速关断的要求时间。
  8. 根据权利要求1-7任一所述的快速关断方法，其特征在于，还包括：
    所述光伏系统中的逆变器对所述光伏系统中直流总线施加电压扰动，以改变所述光伏组件关断器的状态参数、避免所述光伏组件关断器误关断。
  9. 一种光伏组件关断器，其特征在于，包括：开关单元、旁路二极管、驱动单元、参数采集模块、处理器和启动信号接收单元；其中：
    所述参数采集模块，用于采集光伏组件关断器的状态参数，并将采集到的所述状态参数输出至所述处理器；
    所述启动信号接收单元，用于接收启动信号，并将所述启动信号输出至所述处理器；
    所述开关单元，设置于所述光伏组件关断器的正极支路或者负极支路上，用于根据所述处理器的控制，实现所述光伏组件关断器的开通或关断；
    所述旁路二极管，用于在所述光伏组件关断器关断时实现所述光伏组件关 断器的旁路功能；
    所述处理器的输出端通过所述驱动单元与所述开关单元的控制端相连；所述处理器用于结合所述启动信号接收单元、所述参数采集模块、所述驱动单元以及所述开关单元，使所述光伏组件关断器能够实现如权利要求1-7任一所述的快速关断方法。
  10. 根据权利要求9所述的光伏组件关断器，其特征在于，所述参数采集模块包括：电压采样单元和至少一个电流采样单元；
    所述电压采样单元，用于采集所述光伏组件关断器的输入电压，并将采集到的所述输入电压输出至所述处理器；
    所述电流采样单元，用于采集所述光伏组件关断器的输入电流/输出电流，并将采集到的输入电流/输出电流输出至所述处理器。
  11. 根据权利要求10所述的光伏组件关断器，其特征在于，所述启动信号接收单元设置于所述光伏组件关断器的负极支路上、所述旁路二极管的阳极与所述光伏组件关断器的输出端负极之间；
    若所述电流采样单元的个数为一个，则所述电流采样单元设置于所述光伏组件关断器的正极支路上、所述旁路二极管的阴极与所述光伏组件关断器的输出端正极之间；或者，所述电流采样单元设置于所述光伏组件关断器的负极支路上、所述旁路二极管的阳极与所述启动信号接收单元之间；
    若所述电流采样单元的个数为两个，分别为第一电流采样单元和第二电流采样单元，则所述第一电流采样单元设置于所述光伏组件关断器的负极支路上、所述光伏组件关断器的输入端负极与所述启动信号接收单元之间，所述第二电流采样单元设置于所述第一电流采样单元和所述启动信号接收单元的连接点与所述旁路二极管的阳极之间。
  12. 一种光伏系统，其特征在于，包括：至少一个关断系统和至少一个逆变器，所述关断系统包括：直流总线、启动信号发生器、N个光伏模块和N个如权利要求9-11任一所述的光伏组件关断器，N为正整数，其中：
    所述关断系统中，各个所述光伏组件关断器的输出端级联，各个光伏组件关断器的输入端分别与各个光伏模块一一对应相连；各个所述光伏组件关断器级联后的正极通过所述直流总线正极与所述逆变器的对应直流接口正极相连； 各个所述光伏组件关断器级联后的负极通过所述直流总线负极与所述逆变器的对应直流接口负极相连；
    所述启动信号发生器，用于发送启动信号至同一所述关断系统中各个所述光伏组件关断器。
  13. 根据权利要求12所述光伏系统，其特征在于，所述启动信号发生器用于发送启动信号至同一所述关断系统中各个所述光伏组件关断器时，具体用于：
    在同一所述关断系统中各个所述组件关断器的启动过程或所述逆变器的故障恢复过程时，向同一所述关断系统中各个所述光伏组件关断器持续发送所述启动信号，直至对应逆变器进入正常发电状态。
  14. 根据权利要求12或13所述的光伏系统，其特征在于，所述逆变器还用于对各个所述直流总线施加电压扰动，以改变所述光伏组件关断器的状态参数、避免所述光伏组件关断器误关断。
  15. 根据权利要求12或13所述的光伏系统，其特征在于，所述启动信号为电力线载波信号、无线通讯信号或模拟脉冲信号。
  16. 根据权利要求12或13所述的光伏系统，其特征在于，当所述启动信号为电力线载波信号时，所述启动信号符合SunSpec联盟制定的快速关断信号规范。
  17. 根据权利要求12或13所述的光伏系统，其特征在于，所述启动信号发生器集成于所述逆变器中，或者，独立置于所述直流总线上。
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