Shutdown circuit and control method thereof, shutoff device and photovoltaic module shutoff system

Abstract

The present invention provides a shutdown circuit and a control method thereof, a circuit breaker, and a photovoltaic component shutdown system, including a main circuit and a signal circuit; one end of a first capacitor C1 is a first input end of the main circuit, and one end of the first capacitor C1 is respectively connected to the negative electrode of a diode D and one end of a second capacitor C2; the other end of the first capacitor C1 is a second output end of the main circuit, and the other end of the first capacitor C1 is connected to one end of a switch Q; the other end of the switch Q is respectively connected to the positive electrode of the diode D, the other end of the second capacitor C2, and one end of an inductor L; the other end of the inductor L is respectively the first output end and the second input end of the main circuit; the signal circuit controls the switch Q; the main circuit can control the opening and closing of the photovoltaic component to be connected according to the controlled switch Q. The present invention solves the loss problem caused by photovoltaic cables and the difficulty in installing three-part components by adopting a new installation method and circuit structure, and realizes convenient installation of the circuit breaker and high-efficiency operation.

Description

Technical Field

[0001] The present invention relates to the technical field of shutdown systems, and in particular to a shutdown circuit and a control method thereof, a shutdown device, and a photovoltaic module shutdown system. Background Art

[0002] Due to the renewable and clean nature of solar energy, photovoltaic grid-connected power generation technology has developed rapidly. Currently, photovoltaic systems usually consist of multiple photovoltaic modules connected in series to form a string, which is then connected to an inverter to convert DC to AC and connected to the grid.

[0003] Chinese invention patent publication number CN109638786A discloses a photovoltaic module shutdown protection circuit and a module circuit breaker, comprising: a current detection circuit for detecting the output current of a photovoltaic module connected to the module circuit breaker and generating a current detection signal; a backflow detection circuit having an input end connected to the output end of the current detection circuit, for generating a backflow signal when determining, based on the current detection signal, that the photovoltaic module has entered a backflow state; and a backflow control circuit having an input end connected to the output end of the backflow detection circuit and an output end connected to the control end of a switch tube in the module circuit breaker, for controlling the conduction of the switch tube upon receiving the backflow signal.

[0004] like Figure 1 and Figure 2 As shown, the voltage output of the photovoltaic module is turned on and off by the MOS tube, but the current loop of the traditional solution is that the output line OUT+ of the next shutdown device passes through the output line OUT-, then passes through the inductor L1, the switch tube Q1, and then passes through the input line IN-, passes through the photovoltaic module, passes through the shutdown device input line IN+, and then passes through the shutdown device output line to connect to the output line OUT- of the next shutdown device.

[0005] Regarding the above-mentioned related technologies, the inventor believes that the entire circuit includes the losses of the two input lines and two output lines of the circuit breaker. If the component is a three-part component, the output cable of the component is very short, and the input line of the circuit breaker needs to be equipped with an extension cable, which increases the cost, makes installation difficult, and causes large cable losses, and the losses caused by the circuit breaker are also large. Summary of the Invention

[0006] In view of the defects in the prior art, the object of the present invention is to provide a shutdown circuit and a control method thereof, a shutdown device and a photovoltaic module shutdown system.

[0007] A shutdown circuit provided according to the present invention includes a main circuit and a signal circuit;

[0008] The main circuit includes a first capacitor C1, a switch Q, a diode D, a second capacitor C2 and an inductor L;

[0009] One end of the first capacitor C1 is the first input end of the main circuit, and one end of the first capacitor C1 is connected to the cathode of the diode D and one end of the second capacitor C2 respectively;

[0010] The other end of the first capacitor C1 is the second output end of the main circuit, and the other end of the first capacitor C1 is connected to one end of the switch Q;

[0011] The other end of the switch Q is respectively connected to the anode of the diode D, the other end of the second capacitor C2 and one end of the inductor L;

[0012] The other ends of the inductor L are respectively the first output end and the second input end of the main circuit;

[0013] The signal circuit controls the switch Q;

[0014] The main circuit can control the on and off of the photovoltaic components to be connected according to the controlled switch Q.

[0015] Preferably, the signal circuit includes a signal coupling and amplification circuit, a comparison output pulse signal circuit, a CPU, a pulse rectification circuit and a switch tube driving circuit;

[0016] The input of the signal coupling and amplification circuit is connected to one end and the other end of the inductor L respectively;

[0017] The output of the signal coupling and amplifying circuit is connected to the input of the comparison output pulse signal circuit;

[0018] The output of the comparison output pulse signal circuit is connected to the input of the CAP port of the CPU and the input of the pulse rectification circuit respectively;

[0019] The IO port output of the CPU is connected to the first input enable pin EN1 of the switch tube drive circuit;

[0020] The output of the pulse rectifier circuit is connected to the second input enable pin EN2 of the switch tube drive circuit;

[0021] The output of the switch tube driving circuit controls the on and off of the switch Q.

[0022] Preferably, the inductor L is a PLC inductor.

[0023] Preferably, the main circuit further includes a first input line IN+, a second input line IN-, a first output line OUT+ and a second output line OUT-;

[0024] The first input terminal is connected to the first input line IN+;

[0025] The second input terminal is connected to the second input line IN-;

[0026] The first output terminal is connected to the first output line OUT+;

[0027] The second output terminal is connected to the second output line OUT-;

[0028] Preferably, when the shutdown circuits are connected to each other, the first output terminals and the first input terminals between adjacent main circuits are connected to each other through the first output line OUT+ and the first input line IN+.

[0029] According to the present invention, a shutdown circuit control method is provided, comprising the following steps:

[0030] Signal coupling and amplification steps: decoupling and amplifying the PLC signal;

[0031] Comparison output step: converting the PLC signal into a square wave signal;

[0032] Determining step: obtaining a determination result according to the square wave signal;

[0033] Switch tube control step: controlling the on and off of the switch Q according to the judgment result.

[0034] Preferably, the judging step includes the following steps:

[0035] CPU step: collecting the square wave signal, analyzing whether the square wave signal is a start signal, and generating a first enable signal if the start signal is correct; and not generating the first enable signal if the start signal is incorrect;

[0036] Pulse rectification step: converting the square wave signal into a DC signal, generating a second enable signal if the DC signal meets a first predetermined condition, and not generating the second enable signal if the DC signal does not meet the second predetermined condition.

[0037] Preferably, in the switch tube control step, if both the first enable signal and the second enable signal are generated, the switch Q is controlled to be turned on;

[0038] If only one of the first enable signal and the second enable signal is generated or neither is generated, the switch Q is controlled to be turned off.

[0039] A circuit breaker provided according to the present invention includes a circuit breaker circuit and a housing, wherein the circuit breaker circuit is arranged in the housing.

[0040] According to the present invention, a photovoltaic module shutdown system is provided, comprising a plurality of photovoltaic modules, an inverter, a signal controller and a plurality of switch-off devices; the photovoltaic modules and the switch-off devices are arranged in a one-to-one correspondence;

[0041] The positive pole of the first photovoltaic module is respectively connected to the first input terminal of the first main circuit and one end of the inverter, and the positive poles of the remaining photovoltaic modules are respectively connected to the second input terminal of the main circuit corresponding to the previous photovoltaic module;

[0042] The negative electrodes of the photovoltaic modules are respectively connected to the second output terminals of the corresponding main circuits;

[0043] The first input terminals and the first output terminals of adjacent main circuits are connected to each other;

[0044] The second input end of the main circuit is connected to the other end of the inverter;

[0045] The signal controller controls the opening and closing of the circuit breaker.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The present invention adopts a new installation method and circuit structure to solve the loss problem caused by photovoltaic cables and the difficulty in installing three-part components, making the circuit breaker easy to install and working efficiently;

[0048] 2. The present invention solves the CPU failure problem by adopting hardware and software dual redundant control, achieving a safer and more reliable effect;

[0049] 3. The present invention adopts a new main circuit topology scheme to realize that the circuit breaker has only a switch tube, and the PLC inductor is connected in series in the loop, thereby achieving high efficiency of the photovoltaic module shutdown system. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0051] Figure 1 This is a schematic diagram of the overall system of the traditional solution;

[0052] Figure 2 This is a schematic diagram of the shutdown circuit of a traditional shutdown device;

[0053] Figure 3 Schematic diagram of the main circuit in the shutdown circuit of the shutdown device of the present invention;

[0054] Figure 4 This is a schematic diagram highlighting a signal circuit in a shutdown circuit according to the present invention;

[0055] Figure 5 is a schematic diagram of a photovoltaic module shutdown system of the present invention;

[0056] Figure 6 Schematic diagram of a partial circuit of the photovoltaic module shutdown system of the present invention. DETAILED DESCRIPTION

[0057] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0058] The first embodiment of the present invention discloses a shutdown circuit, such as Figure 3 As shown, it includes a main circuit. The main circuit includes a first input line IN+, a second input line IN-, a first output line OUT+, a second output line OUT-, a first capacitor C1, a switch Q (switch tube), a diode D, a second capacitor C2, and an inductor L. One end of the first capacitor C1 is the first input end of the main circuit; and one end of the first capacitor C1 is respectively connected to the cathode of the diode D and one end of the second capacitor C2; the other end of the first capacitor C1 is the second output end of the main circuit, and the other end of the first capacitor C1 is connected to one end of the switch Q; the other end of the switch Q is respectively connected to the anode of the diode D, the other end of the second capacitor C2, and one end of the inductor L; the other end of the inductor L is respectively the first output end and the second input end of the main circuit. The first input end is connected to the first input line IN+; the second input end is connected to the second input line IN-; the first output end is connected to the first output line OUT+; and the second output end is connected to the second output line OUT-.

[0059] When the shutdown circuits are interconnected, the first output terminals and first input terminals of adjacent main circuits are interconnected via the connected first output line OUT+ and first input line IN+. In traditional solutions, if the module is a three-part module, the module's output cable is very short, and the shutdown circuit input line also requires an extension cable, which increases costs and makes installation difficult. By interconnecting the first output terminals and first input terminals of adjacent main circuits via the connected first output line OUT+ and first input line IN+, a new installation method is adopted and applied to the photovoltaic module shutdown system, solving the problems of photovoltaic cable losses and the difficulty of installing three-part modules, making the shutdown circuit installation convenient and efficient.

[0060] The first capacitor C1 is the input filter capacitor. The inductor L is the PLC inductor. The second capacitor C2 is the output capacitor. The diode D is a freewheeling diode. The main circuit controls the on and off of the photovoltaic module. The first capacitor C1 is connected across the first input line IN+ and the second output line OUT-. The switch Q and the inductor L are connected in series and are respectively connected to the second output line OUT- and the second input line IN-. One end of the switch Q is connected to the second output line OUT-, and the other end of the switch Q is connected to one end of the inductor L. The other end of the inductor L is connected to the second input line IN-. The diode D is connected in parallel with the output capacitor C2. The anode of the diode D is connected to the series connection point of the switch Q and the inductor L. The cathode of the diode D is connected to the first input line IN+, and the first output line OUT+ is connected to the second input line IN-.

[0061] The main circuit realizes the opening and closing functions through the switch Q, and realizes the collection of PLC signals through the inductor L. The diode D provides a freewheeling circuit for the circuit breaker. The first capacitor C1 is an input filter capacitor to avoid high voltage spikes when the switch Q is turned off. The second capacitor C2 provides a circuit for the PLC signal when the circuit breaker is turned off.

[0062] On the basis of the first embodiment, the second embodiment of the present invention further discloses a shutdown circuit, such as Figure 4 As shown, the shutdown circuit also includes a signal circuit. The signal circuit controls the opening and closing of the main circuit. The signal circuit opens and closes the main circuit. The input end of the signal circuit is connected to the two ends of the inductor L. The output end of the signal circuit is connected to the switch Q. The input end of the signal circuit is the input of the signal coupling and amplification circuit, and the output end of the signal circuit is the output of the switch tube drive circuit. The switch tube drive circuit includes a drive circuit built with an ordinary triode. The signal circuit includes a signal coupling and amplification circuit (PLC signal decoupling and amplification circuit), a comparison output pulse signal circuit, a CPU, a pulse rectifier circuit, and a switch tube drive circuit. The inputs of the signal coupling and amplification circuit are connected to one end and the other end of inductor L, respectively. The inputs of the signal coupling and amplification circuit are also connected to the two ends of inductor L in the main circuit. The output of the signal coupling and amplification circuit is connected to the input of the comparison output pulse signal circuit. The output of the comparison output pulse signal circuit is connected to the CPU's CAP port and the input of the pulse rectifier circuit, respectively. The output of the CPU's IO port is connected to the first input enable pin EN1 of the switch driver circuit, and the output of the pulse rectifier circuit is connected to the second input enable pin EN2 of the switch driver circuit. The output of the switch driver circuit controls the on and off of switch Q. The signal coupling and amplification circuit uses an op amp and capacitors for decoupling and amplification. The CPU is a NUVOTON MS51FB9AE. The comparison output pulse signal circuit is implemented using a comparator. The pulse rectifier circuit uses conventional diode rectification. The signal circuit controls switch Q; the main circuit can control the on and off of the connected photovoltaic panels based on the control of switch Q.

[0063] On the basis of the first or second embodiment, the third embodiment of the present invention further discloses a shutdown circuit control method, such as Figure 3 and Figure 4 As shown, the process includes the following steps: a signal coupling and amplification step: collecting and amplifying the PLC signal. a comparison and output step: converting the PLC signal into a square wave signal. a judgment step: obtaining a judgment result based on the square wave signal. The judgment step includes the following steps: a CPU step: collecting the square wave signal and analyzing whether the square wave signal is a start signal. If the start signal is correct, a first enable signal is generated; if the start signal is incorrect, the first enable signal is not generated. a pulse rectification step: converting the square wave signal into a DC signal. If the DC signal meets the first predetermined condition, a second enable signal is generated. If the DC signal does not meet the second predetermined condition, the second enable signal is not generated. a switch tube control step: controlling the on and off of the switch Q according to the judgment result. If both the first enable signal and the second enable signal are generated, the switch Q is controlled to be on. If only one of the first enable signal and the second enable signal is generated or neither is generated, the switch Q is controlled to be off.

[0064] The signal coupling and amplification circuit collects PLC signals and amplifies them to the required value. The comparison output pulse signal circuit converts the PLC signal into a square wave signal. The CPU collects the square wave signal and analyzes whether it is an on signal. If the signal is correct, the switch driver is enabled and the circuit breaker is activated. If the signal is incorrect, the switch driver is disabled after a period of time, and the circuit breaker does not operate. The pulse rectifier circuit converts the square wave signal into a DC signal used to enable the switch driver. The switch driver circuit drives the switch.

[0065] The signal circuit realizes dual redundant control of the hardware circuit and the CPU. After decoupling and amplifying the PLC signal, it is approximated as a square wave signal through a comparator. One path is input to the CAP port of the CPU, and the other path is input to the pulse rectifier circuit. The CPU will control the opening and closing of the circuit breaker switch tube by checking whether the collected pulse signal frequency (for example, 131k and 143K) meets the requirements. The pulse rectifier circuit converts the pulse signal into a DC voltage. When the DC voltage is higher than a first preset value (greater than 1.5V to enable), the switch tube is enabled to turn on. When the DC voltage is lower than a second preset value (less than 0.7V to disable), the switching of switch Q is prohibited, that is, switch Q is turned off. The switch tube is turned on only when both the CPU and the pulse rectifier circuit are enabled, otherwise the switch tube is turned off. In this way, dual redundant control of the switch tube is realized, which has good safety and high reliability.

[0066] On the basis of the first or second embodiment, the fourth embodiment of the present invention further discloses a circuit breaker, such as Figure 5 and Figure 6 As shown, it includes a shutoff circuit and a shell, and the shutoff circuit is arranged in the shell.

[0067] Based on the fourth embodiment, the present invention also discloses a photovoltaic module shutdown system, such as Figure 5 and Figure 6 As shown, it includes multiple photovoltaic modules PV, inverters, signal controllers (PLC signal controllers) and multiple circuit breakers; the photovoltaic modules and the circuit breakers are set in a one-to-one correspondence.

[0068] The positive pole of the first photovoltaic module is connected to the first input end of the first main circuit and one end of the inverter respectively; the positive poles of the remaining photovoltaic modules are connected to the second input end of the main circuit corresponding to the previous photovoltaic module; the negative pole of the photovoltaic module is connected to the second output end of the corresponding main circuit; the first input end and the first output end of adjacent main circuits are connected to each other; the second input end of the last main circuit is connected to the other end of the inverter; the signal controller controls the opening and closing of the circuit breaker.

[0069] The circuit breaker is detachable. The first input terminal IN+ of the circuit breaker and the second input terminal IN- of the circuit breaker are both provided with male connectors, and the first output line OUT+ of the circuit breaker and the second output line OUT- of the circuit breaker are both provided with female connectors. The positive pole of the first photovoltaic module is provided with a female to two male connector, the positive poles of the remaining photovoltaic modules are provided with male connectors, and the negative poles of the photovoltaic modules are provided with female connectors. One end of the inverter is provided with a female connector, and the other end of the inverter is provided with a male connector. The one female to two male connector of the positive pole of the first photovoltaic module is respectively connected to the female connector of the first input line IN+ of the first circuit breaker and the female connector of one end of the inverter, and the male connectors of the positive poles of the remaining photovoltaic modules are respectively connected to the female connector of the second input line IN- of the circuit breaker corresponding to the previous photovoltaic module. n represents the number.

[0070] The female connector at the negative pole of each PV module is connected to the male connector of the second output line OUT- of the corresponding circuit breaker. The female connectors of the first input line IN+ between adjacent circuit breakers are connected to the male connectors of the first output line OUT+. The first output line OUT+ of the final circuit breaker is connected to a plug (blocked with a waterproof plug) or a male connector, which is connected to a female connector. The waterproof plug is an MC4 waterproof plug. The male connector at the other end of the inverter is connected to the female connector of the second input terminal IN- of the final circuit breaker. The male and female connectors plug into each other according to the connection structure of the PV module shutdown system. The one-female to two-male connector plugs into the corresponding female connector according to the connection structure of the PV module shutdown system.

[0071] The first input line, IN+, connects to the first output line, OUT+, of the previous PV module, while the second output line, OUT-, connects to the negative terminal of the previous PV module. This way, the first input line, IN+, and the second output line, OUT-, serve as the positive and negative terminals of the previous module, respectively, providing power to the entire PV module. Diode D provides a freewheeling circuit for the module, and switch Q switches the module on and off. The second input line, IN-, connects to the positive terminal of the next PV module. The current loop between the two modules follows the second input line, IN-, through inductor L. Switch Q then flows to the second output line, OUT-, the negative terminal of the previous PV module, bypassing the first output line, OUT+, and the first input line, IN+. Since the PV module is installed between the two modules, the PV cables for the second output lines, OUT-, and IN- essentially do not need to be extended. For different PV modules, the entire PV module eliminates the losses associated with PV cables, achieving high efficiency. The first input line, IN+, IN-, OUT+, and OUT- are cables.

[0072] A drawback of traditional solutions is the high photovoltaic cable losses, especially in triplicate modules, which require external extension cables. The new solution changes the circuit structure, placing the switch in series between the two modules. This eliminates photovoltaic cable losses and improves efficiency. This invention utilizes a novel main circuit topology, with the switch as the only switch in the circuit breaker, and the PLC inductor in series within the loop, achieving high system efficiency. Furthermore, the signal circuit is driven by dual-enabling switches, EN1 and EN2, for high reliability.

[0073] PV panels receive energy and output it to the inverter; a circuit breaker connects or disconnects the PV panel's energy output; the inverter inverts the energy to the grid; and a signal controller controls the opening and closing of the circuit breaker. The PV panels serve as input, the circuit breaker disconnects the PV panel's output, the inverter inverts the PV panel's energy to the grid, and the controller sends a PLC signal to open and close the circuit breaker. The PLC signal is coupled to the PV cable via a magnetic ring for transmission.

[0074] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0075] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A shutdown circuit, characterized in that: Including main circuit and signal circuit; The main circuit includes a first capacitor C1, a switch Q, a diode D, a second capacitor C2 and an inductor L; One end of the first capacitor C1 is the first input end of the main circuit, and one end of the first capacitor C1 is connected to the cathode of the diode D and one end of the second capacitor C2 respectively; The other end of the first capacitor C1 is the second output end of the main circuit, and the other end of the first capacitor C1 is connected to one end of the switch Q; The other end of the switch Q is respectively connected to the anode of the diode D, the other end of the second capacitor C2 and one end of the inductor L; The other ends of the inductor L are respectively the first output end and the second input end of the main circuit; The signal circuit controls the switch Q; The main circuit can control the opening and closing of the photovoltaic assembly to be connected according to the controlled switch Q; The signal circuit includes a signal coupling and amplification circuit, a comparison output pulse signal circuit, a CPU, a pulse rectification circuit and a switch tube driving circuit; The input of the signal coupling and amplification circuit is connected to one end and the other end of the inductor L respectively; The output of the signal coupling and amplifying circuit is connected to the input of the comparison output pulse signal circuit; The output of the comparison output pulse signal circuit is connected to the input of the CAP port of the CPU and the input of the pulse rectification circuit respectively; The IO port output of the CPU is connected to the first input enable pin EN1 of the switch tube drive circuit; The output of the pulse rectifier circuit is connected to the second input enable pin EN2 of the switch tube drive circuit; The output of the switch tube driving circuit controls the on and off of the switch Q; The switch tube driving circuit is configured to: drive the switch Q to turn on when both the first input enable pin EN1 and the second input enable pin EN2 receive an enable signal; and drive the switch Q to turn off when at least one of the first input enable pin EN1 and the second input enable pin EN2 does not receive an enable signal; The main circuit further includes a first input line IN+, a second input line IN-, a first output line OUT+ and a second output line OUT-; The first input terminal is connected to the first input line IN+; The second input terminal is connected to the second input line IN-; The first output end is connected to the first output line OUT+; The second output terminal is connected to the second output line OUT-; When the shutdown circuits are connected to each other, the first output terminals and the first input terminals between adjacent main circuits are connected to each other through the connected first output line OUT+ and the first input line IN+.

2. The shutdown circuit according to claim 1, characterized in that: The inductor L is a PLC inductor.

3. A shutdown circuit control method, characterized in that: The shutdown circuit according to any one of claims 1 to 2 is applied, comprising the following steps: Signal coupling and amplification steps: decoupling and amplifying the PLC signal; Comparison output step: converting the PLC signal into a square wave signal; Determining step: obtaining a determination result according to the square wave signal; Switch tube control step: controlling the on and off of the switch Q according to the judgment result.

4. The shutdown circuit control method according to claim 3, characterized in that: The judging step comprises the following steps: CPU step: collecting the square wave signal, analyzing whether the square wave signal is a start signal, and generating a first enable signal if the start signal is correct; and not generating the first enable signal if the start signal is incorrect; Pulse rectification step: converting the square wave signal into a DC signal, generating a second enable signal if the DC signal meets a first predetermined condition, and not generating the second enable signal if the DC signal does not meet the second predetermined condition.

5. The shutdown circuit control method according to claim 4, characterized in that: In the switch tube control step, if both the first enable signal and the second enable signal are generated, the switch Q is controlled to be turned on; If only one of the first enable signal and the second enable signal is generated or neither is generated, the switch Q is controlled to be turned off.

6. A circuit breaker with a shutdown circuit according to any one of claims 1 to 2, characterized in that: The invention comprises a shutoff circuit and a shell, wherein the shutoff circuit is arranged in the shell.

7. A photovoltaic module shutdown system with the shutdown device according to claim 6, characterized in that: It includes a plurality of photovoltaic modules, an inverter, a signal controller and a plurality of circuit breakers; the photovoltaic modules and the circuit breakers are arranged in a one-to-one correspondence; The positive pole of the first photovoltaic module is respectively connected to the first input terminal of the first main circuit and one end of the inverter, and the positive poles of the remaining photovoltaic modules are respectively connected to the second input terminal of the main circuit corresponding to the previous photovoltaic module; The negative electrodes of the photovoltaic modules are respectively connected to the second output terminals of the corresponding main circuits; The first input terminals and the first output terminals of adjacent main circuits are connected to each other; The second input end of the main circuit is connected to the other end of the inverter; The signal controller controls the opening and closing of the circuit breaker.

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