Photovoltaic turn-off device control circuit, photovoltaic turn-off device and photovoltaic power generation system

Abstract

The utility model provides a photovoltaic turn-off device control circuit, a photovoltaic turn-off device and a photovoltaic power generation system. The photovoltaic turn-off device control circuit comprises a first switch module, a second switch module and a control module, the control module is respectively connected with the first switch module and the second switch module, and the first switch module and the second switch module are connected between a photovoltaic module board and a series power generation circuit. Wherein the control module firstly controls the transistor of the first switch module to be switched on so as to connect the photovoltaic module panel and the series power generation circuit, and then controls the second switch module to be switched on and switch off the transistor of the first switch module, so that the photovoltaic module panel and the series power generation circuit are connected through the second switch module. Therefore, the second switch module can replace the transistor of the first switch module to be communicated with the photovoltaic module panel and the series power generation circuit, the transistor does not need to be heated for a long time, the service life of the transistor can be prolonged, and meanwhile photovoltaic power generation loss is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic power generation, and in particular to a photovoltaic shut-off control circuit, a photovoltaic shut-off device and a photovoltaic power generation system. Background Art

[0002] In order to meet electrical safety regulations, photovoltaic power generation systems are equipped with photovoltaic circuit breakers at the output end of photovoltaic modules. Photovoltaic circuit breakers are safety switch devices used in DC photovoltaic power generation systems. A power generation system can be obtained by connecting several photovoltaic module panels in series. When sunlight shines on the photovoltaic module panels, the photovoltaic module panels can generate direct current, which is then transmitted to the inverter circuit, which further converts the direct current into alternating current for grid-connected power generation.

[0003] When the photovoltaic power generation system generates electricity, the photovoltaic shut-off device receives a frequency shift keying (FSK) signal transmitted in the form of electric waves and continuously sent at fixed time intervals according to the Sunspec protocol. After the photovoltaic shut-off device analyzes the signal, it will maintain the state of the component panel power generation and the output port of the shut-off device being turned on. The current mainstream solution is to control the photovoltaic fast shut-off device to turn on or off through a low internal resistance transistor, such as a field effect transistor (MOSFET). Due to the working characteristics of the product, it will always be in the on state when generating electricity during the day. At the same time, the power generation current is between 10-20A, or even higher. The internal resistance of the low internal resistance transistor is generally 3-10mΩ, and there will be a significant temperature rise. If the transistor is in a high temperature working state for a long time, the reliability of the components will decrease, thereby affecting the product life, and it will bring certain power generation losses and affect the power generation efficiency. Utility Model Content

[0004] The purpose of the embodiments of the present application is to provide a photovoltaic shut-off control circuit, a photovoltaic shut-off and a photovoltaic power generation system, which are used to solve the problem in the prior art that the transistors of the photovoltaic shut-off are in a high temperature state for a long time, resulting in a short life.

[0005] In order to achieve the above-mentioned object, the first aspect of the present application provides a photovoltaic shut-off control circuit, comprising a first switch module, a second switch module and a control module, wherein the control module is connected to the first switch module and the second switch module respectively, and the first switch module and the second switch module are connected between the photovoltaic component panel and the series power generation electronic circuit; the series power generation electronic circuit comprises a wire connecting the photovoltaic component panel and the inverter circuit;

[0006] The first switch module includes a transistor, which is used to be turned on or off under the control of the control module;

[0007] The control module is used to control the transistor of the first switch module to be turned on to connect the photovoltaic component panel and the series power generation electronic circuit, and then control the second switch module to turn on and turn off the transistor of the first switch module, so that the photovoltaic component panel and the series power generation electronic circuit are connected through the second switch module.

[0008] In the embodiment of the present application, the second switch module includes a first switch tube and a first relay;

[0009] The first switch tube is connected to the control module and the first relay respectively, and the first relay is also connected to the photovoltaic component panel and the series generating electronic circuit;

[0010] Among them, the control module controls the first switch tube to be turned on and off, and then controls the first relay to be in a normally open state or a normally closed state. When the first relay is in the normally open state, the photovoltaic component panel and the series power generation electronic circuit are connected through the first relay.

[0011] In the embodiment of the present application, the first switch tube includes a first base, a first collector and a first emitter, the first base is connected to the control module, and the first emitter is grounded;

[0012] The first relay includes a first common terminal, a first normally closed terminal, a first normally open terminal, a first positive power supply terminal and a first negative power supply terminal, the first common terminal and the positive power supply terminal are connected to the positive electrode of the series-connected electronic circuit, the first normally open terminal is connected to the positive electrode of the photovoltaic module panel, and the negative power supply terminal is connected to the first collector of the first switch tube;

[0013] When the first switch tube is turned on, the first common terminal and the first normally open terminal of the first relay are closed, so that the photovoltaic component panel is connected to the series power generation electronic circuit.

[0014] In the embodiment of the present application, the difference between the on-state internal resistance of the first relay and the internal resistance of the transistor is within a preset range.

[0015] In an embodiment of the present application, a bypass module is also included, wherein two ends of the bypass module are respectively connected to the positive pole and the negative pole of the series power generation sub-circuit, and the bypass module is used to connect the positive pole and the negative pole of the series power generation sub-circuit when the first switch module and the second switch module are turned off.

[0016] In the embodiment of the present application, the bypass module includes a second switch tube and a second relay;

[0017] The second switch tube is connected to the control module and the second relay respectively, and the second relay is also connected to the positive electrode and the negative electrode of the series-connected electronic circuit;

[0018] Among them, the control module controls the second switch tube to be turned on and off, and then controls the second relay to be in a normally open state or a normally closed state. When the second relay is in a normally closed state, the positive and negative electrodes of the series generating electronic circuit are connected.

[0019] In the embodiment of the present application, the second switch tube includes a second base, a second collector and a second emitter, the second base is connected to the control module, and the second emitter is grounded;

[0020] The second relay includes a second common terminal, a second normally closed terminal, a second normally open terminal, a second positive power supply terminal and a second negative power supply terminal, the second common terminal is connected to the positive electrode of the series power generation electronic circuit, the second normally closed terminal is connected to the negative electrode of the series power generation electronic circuit, the second positive power supply terminal is connected to the positive electrode of the photovoltaic component panel, and the second negative power supply terminal is connected to the collector of the second switch tube;

[0021] Wherein, when the second switch tube is disconnected, the second common terminal and the second normally closed terminal of the second relay are closed, and the positive electrode and the negative electrode of the series generating subcircuit are connected.

[0022] A second aspect of the present application provides a photovoltaic shutdown device, comprising the photovoltaic shutdown device control circuit described above.

[0023] A third aspect of the present application provides a photovoltaic power generation system, comprising:

[0024] A plurality of the above photovoltaic shut-off devices;

[0025] A plurality of photovoltaic assembly panels, each photovoltaic assembly panel is connected to a first end of a corresponding photovoltaic disconnector;

[0026] The series power generation unit includes multiple series power generation electronic circuits, each of which corresponds to a photovoltaic component panel and is connected to the second end of the corresponding photovoltaic switch, and is used to connect multiple photovoltaic component panels in series to transmit the generated direct current to the inverter circuit.

[0027] In the embodiment of the present application, the positive electrode of each series-connected power-generating sub-circuit is connected to the negative electrode of the series-connected power-generating sub-circuit of the previous stage, and the negative electrode is connected to the positive electrode of the series-connected power-generating sub-circuit of the next stage.

[0028] The present application adds a second switch module to the photovoltaic shut-off control circuit, connects the first switch module and the second switch module between the photovoltaic module panel and the series power generation electronic circuit, and controls the second switch module to turn on and off the transistor of the first switch module after controlling the transistor of the first switch module to connect the photovoltaic module panel and the series power generation electronic circuit through the control module, so that the photovoltaic module panel and the series power generation electronic circuit are connected through the second switch module. In this way, the second switch module can replace the transistor of the first switch module to connect the photovoltaic module panel and the series power generation electronic circuit, and the transistor does not need to heat for a long time, which can extend the life of the transistor and also reduce the loss of photovoltaic power generation.

[0029] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 This is a functional module diagram of a photovoltaic shutdown control circuit according to an embodiment of the present application;

[0032] Figure 2 A schematic diagram of a circuit principle of a photovoltaic shutdown control circuit according to an embodiment of the present application;

[0033] Figure 3 This is a functional module diagram of a photovoltaic shutdown control circuit according to another embodiment of the present application;

[0034] Figure 4 A schematic diagram of a circuit principle of a photovoltaic shutdown control circuit according to another embodiment of the present application;

[0035] Figure 5 A schematic diagram of the structure of a photovoltaic power generation system according to an embodiment of the present application.

[0036] Description of Reference Numerals

[0037] 100, photovoltaic switch; 200, photovoltaic module panel; 300, series power generation unit; 110, first switch module; 120, second switch module; 130, control module; 140, bypass module; 310, series power generation electronic circuit. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0039] In the description of the present application, it should be understood that the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In the present application, the word "exemplary" is used to mean "used as an example, illustration or description". Any embodiment described as "exemplary" in the present application is not necessarily interpreted as being more preferred or more advantageous than other embodiments. In order to enable any technician in the field to implement and use the present application, the following description is given. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present application can also be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid unnecessary details that make the description of the present application obscure. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the widest range of principles and features disclosed in the present application.

[0040] Figure 1 Schematic diagram of the functional modules of a photovoltaic shutdown control circuit according to an embodiment of the present application. Figure 1 As shown, in an embodiment of the present application, a photovoltaic shut-off control circuit is provided, including a first switch module 110, a second switch module 120 and a control module 130, wherein the control module 130 is connected to the first switch module 110 and the second switch module 120 respectively, and the first switch module 110 and the second switch module 120 are connected between the photovoltaic component panel 200 and the series power generation electronic circuit 310; the series power generation electronic circuit 310 includes a wire connecting the photovoltaic component panel and the inverter circuit; the first switch module 110 includes a transistor for turning on or off under the control of the control module 130; the control module 130 is used to control the second switch module 120 to turn on and turn off the transistor of the first switch module 110 after controlling the transistor of the first switch module 110 to turn on to connect the photovoltaic component panel 200 and the series power generation electronic circuit 310, so that the photovoltaic component panel 200 and the series power generation electronic circuit 310 are connected through the second switch module 120.

[0041] Among them, the photovoltaic cut-off control circuit of the embodiment of the present application can be used in the photovoltaic cut-off of the photovoltaic power generation system, and the photovoltaic power generation system can include multiple photovoltaic cut-offs, and the photovoltaic cut-off control circuit of each photovoltaic cut-off is connected in parallel to the corresponding photovoltaic assembly panel 200. The photovoltaic assembly panel 200 can be connected to the series power generation unit through the photovoltaic cut-off. The series power generation unit includes multiple series power generation electronic circuits 310, and each series power generation electronic circuit 310 corresponds to a photovoltaic cut-off, that is, corresponds to a photovoltaic assembly panel 200. The series power generation electronic circuit 310 includes a wire connecting the photovoltaic assembly panel 200 and the inverter circuit, which is used to transmit the direct current generated by the photovoltaic assembly panel 200 to the inverter circuit, so that the inverter circuit further converts the direct current into alternating current for grid-connected power generation. In an example, each series power generation electronic circuit 310 may include two ports, a positive pole OUT+ and a negative pole OUT-, and the positive pole OUT+ of each level of the series power generation electronic circuit 310 is connected to the negative pole OUT- of the series power generation electronic circuit 310 of the previous level, and the negative pole OUT- is connected to the positive pole OUT+ of the series power generation electronic circuit 310 of the next level. That is, the negative electrode OUT- of the previous series power generation sub-circuit 310 in the series power generation unit 300 is connected to the positive electrode OUT+ of the current series power generation sub-circuit 310, and the positive electrode OUT+ of the first series power generation sub-circuit 310 and the negative electrode OUT- of the last series power generation sub-circuit 310 are respectively connected to the inverter circuit. Through the above connection method, multiple series power generation sub-circuits 310 can be connected in series to form a series power generation unit to transmit the DC power generated by multiple photovoltaic module panels 200 to the inverter circuit.

[0042] In the embodiment of the present application, for each photovoltaic shut-off control circuit, a first switch module 110, a second switch module 120 and a control module 130 may be included. The control module 130 is connected to the first switch module 110 and the second switch module 120 respectively, so as to control the on or off of the first switch module 110 and the second switch module 120. The first switch module 110 and the second switch module 120 are both connected between the photovoltaic component panel 200 and the series power generation electronic circuit 310, so that the control module 130 can choose to turn on one of the first switch module 110 and the second switch module 120 to connect the photovoltaic component panel 200 and the series power generation electronic circuit 310. In one example, the control module 130 can use a microcontroller unit (MCU). MCU has the characteristics of small size, low power consumption, high integration, easy programming and wide application.

[0043] The first switch module 110 includes a transistor, which is used to cut off or connect the photovoltaic component panel 200 and the series power generation electronic circuit 310. Among them, the transistor may include but is not limited to a triode or a field effect tube. Since the field effect tube has the characteristics of fast switching speed, small control voltage signal, high efficiency, low noise, etc., the photovoltaic shut-off control circuit usually uses a field effect tube with low internal resistance. The field effect tube may include but is not limited to: metal oxide semiconductor field effect transistor (MOSFET), junction field effect transistor (JFET), etc. When the transistor is turned on for a long time, it is in a high temperature working state for a long time, and the reliability will decrease over time, thereby affecting the product life. Therefore, the embodiment of the present application also adds a second switch module 120 that can also connect the photovoltaic component panel 200 and the series power generation electronic circuit 310, and the second switch module 120 is also connected to the control module 130. Therefore, the control module 130 can control the conduction or disconnection of the first switch module 110, and can also control the conduction or disconnection of the second switch module 120.

[0044] In the embodiment of the present application, the control module 130 first drives the transistor to turn on so that the photovoltaic module panel 200 and the series power generation electronic circuit 310 are connected; then, the second switch module 120 is controlled to turn on, which can also connect the photovoltaic module panel 200 and the series power generation electronic circuit 310. In order to reduce the working time of the transistor, the control module 130 can control the transistor of the first switch module 110 to turn off. At this time, the photovoltaic module panel 200 and the series power generation electronic circuit 310 are still connected through the second switch module 120. In this way, the transistor will not be in a working state for a long time, which greatly extends the service life of the transistor.

[0045] In the embodiment of the present application, the second switch module 120 replaces the transistor of the first switch module 110 to connect the photovoltaic component panel 200 and the series power generation electronic circuit 310. The transistor does not need to heat up for a long time, which can extend the life of the transistor and also reduce the photovoltaic power generation loss.

[0046] In the embodiment of the present application, the second switch module 120 includes a first switch tube and a first relay.

[0047] The first switch tube is connected to the control module 130 and the first relay respectively, and the first relay is also connected to the photovoltaic component panel 200 and the series power generation electronic circuit 310.

[0048] Among them, the control module 130 controls the first switch tube to be turned on and off, and then controls the first relay to be in a normally open state or a normally closed state. When the first relay is in the normally open state, the photovoltaic component panel 200 is connected to the series power generation circuit 310 through the first relay.

[0049] In the embodiment of the present application, the photovoltaic assembly panel 200 and the series power generation electronic circuit 310 can be connected by replacing the transistor with the combination of the first switch tube and the first relay. The first switch tube is used to control the switching operation of the current. In one example, the first switch tube can select a bipolar transistor (BJT). The first switch tube is connected to the control module 130 and the first relay respectively. The control module 130 drives the first switch tube so that the first switch tube is turned on. After the first switch tube is turned on, the first relay is activated and the state is switched to the normally open state. Since the first relay connects the photovoltaic assembly panel 200 and the series power generation electronic circuit 310, at this time, the first relay can connect the photovoltaic assembly panel 200 and the series power generation electronic circuit 310. In this way, by driving the first switch tube and the first relay to turn on by the control module, the transistor of the first switch module 110 can be replaced to connect the photovoltaic assembly panel 200 and the series power generation electronic circuit 310.

[0050] The following description is made by taking the transistor as a field effect transistor, the first switch tube as a bipolar transistor, and the first relay as an electromagnetic relay as an example.

[0051] Figure 2 FIG. 1 is a schematic diagram of a photovoltaic shutdown control circuit according to an embodiment of the present application. Figure 2 As shown, in the embodiment of the present application, the first switch tube Q2 includes a first base b1, a first collector c1 and a first emitter e1, the first base b1 is connected to the control module 130, and the first emitter e1 is grounded.

[0052] The first relay K1 includes a first common terminal 11, a first normally closed terminal 12, a first normally open terminal 13, a first positive power supply terminal 14 and a first negative power supply terminal 15. The first common terminal 11 and the first positive power supply terminal 14 are connected to the positive electrode OUT+ of the series power generation electronic circuit 310, the first normally open terminal 13 is connected to the positive electrode PV+ of the photovoltaic component panel 200, and the first negative power supply terminal 15 is connected to the first collector c1 of the first switch tube Q2;

[0053] When the first switch tube Q2 is turned on, the first common terminal 11 and the first normally open terminal 13 of the first relay K1 are closed, so that the photovoltaic component panel 200 is connected to the series power generation electronic circuit 310 .

[0054] In the embodiment of the present application, if the control module 130 applies a forward bias voltage to the first base b1, a forward bias is formed at the junction of the first base b1 and the first emitter e1, which can significantly increase the current from the first collector c1 to the first emitter e1. When the current of the first base b1 exceeds the starting current, the first switch tube Q2 is turned on. After the first switch tube Q2 is turned on, the formed current flows into the first relay K1. The coil of the first relay K1 includes two ends, namely, the positive pole 14 of the first power supply end and the negative pole 15 of the first power supply end, and the negative pole 15 of the first power supply end is connected to the first collector c1 of the first switch tube Q2. When the current flows through the coil of the first relay K1, a magnetic field is generated. Due to the effect of electromagnetic induction, the generated magnetic field will attract the contacts, which are made of conductive materials and include a first normally closed end 12 and a first normally open end 13. When the power is not on, the first normally closed end 12 is in a closed state, and the first normally open end 13 is in an open state. When the coil is energized, the magnetic field will attract the contacts, causing the first normally closed terminal 12 to open and the first normally open terminal 13 to close, thereby turning on the first relay K1. Since the first normally open terminal 13 is connected to the positive pole PV+ of the photovoltaic module panel, and the first common terminal 11 is connected to the positive pole OUT+ of the series power generation sub-circuit 310; therefore, when the first common terminal 11 and the first normally open terminal 13 of the first relay K1 are closed, the photovoltaic module panel 200 and the series power generation sub-circuit 310 are connected.

[0055] In the embodiment of the present application, the difference between the on-state internal resistance of the first relay K1 and the internal resistance of the field effect transistor Q1 is within a preset range.

[0056] Specifically, the embodiment of the present application can select a first relay K1 whose on-resistance is similar to the internal resistance of the field effect tube Q1, so as to ensure the stability of the photovoltaic shut-off control circuit. Therefore, the difference between the on-resistance of the first relay K1 and the internal resistance of the field effect tube Q1 can be set within a preset range. In one example, since the internal resistance of the field effect tube Q1 of the photovoltaic shut-off control circuit is generally in the range of 3-10mΩ, the internal resistance of the first relay K1 can be 3-8mΩ. In the case where the internal resistance of the relay is similar to that of the field effect tube Q1, the service life can be as long as 15-25 years. Therefore, not only the service life of the field effect tube Q1 is greatly extended, but also the stability of the photovoltaic shut-off control circuit can be improved.

[0057] Figure 3 FIG. 1 is a functional module diagram of a photovoltaic shutdown control circuit according to another embodiment of the present application. Figure 3 As shown, in an embodiment of the present application, a bypass module 140 is also included, and the two ends of the bypass module 140 are respectively connected to the positive pole and the negative pole of the series power generation sub-circuit 310. The bypass module 140 is used to connect the positive pole and the negative pole of the series power generation sub-circuit 310 when the first switch module 110 and the second switch module 120 are turned off.

[0058] For example, as an example, when the control module 130 fails, the first switch module 110 and the second switch module 120 cannot be controlled to be turned on. At this time, the first switch module 110 and the second switch module 120 are both in a disconnected state. If a certain series power generation circuit in the series power generation unit is not turned on, the photovoltaic power generation system will stop running, thereby causing economic losses. Therefore, the embodiment of the present application is also provided with a bypass module 140, and the two ends of the bypass module 140 are respectively connected to the positive and negative electrodes of the series power generation circuit 310, which is used to connect the positive and negative electrodes of the series power generation circuit 310 when the first switch module 110 and the second switch module 120 are turned off, so that the current loop of the series power generation circuit of the string can flow through the bypass module 140, which is equivalent to jumping out of the faulty photovoltaic component panel to keep the photovoltaic power generation system running.

[0059] like Figure 2 As shown, in one implementation of the embodiment of the present application, the bypass module 140 includes a bypass diode D, and the bypass diode D is connected between the positive electrode and the negative electrode of the series power generation sub-circuit.

[0060] The bypass diode is also called a protection diode or a reverse parallel diode, which is used to protect other electronic components from damage by reverse voltage. When a reverse voltage is applied to the bypass diode D, if the reverse voltage exceeds the reverse rated voltage of the diode, the bypass diode D will quickly turn on. In an embodiment of the present application, the bypass diode D can be connected between the positive and negative poles of the series power generation circuit. When the control module 130 fails, the first switch module 110 and the second switch module 120 are turned off. At this time, the current loop of the series power generation circuit can flow through the bypass diode D to ensure the continued operation of the photovoltaic power generation system.

[0061] However, the voltage drop of the bypass diode is generally between 0.3-0.5, and a current of 10-20 A flowing through it will cause serious heating. Therefore, in the embodiment of the present application, a switch tube and a relay can be used to replace the bypass diode.

[0062] Based on this, in another implementation of the embodiment of the present application, the bypass module 140 includes a second switch tube and a second relay;

[0063] The second switch tube is connected to the control module 130 and the second relay respectively, and the second relay is also connected to the positive electrode and the negative electrode of the series-connected electric circuit 310;

[0064] The control module 130 controls the second switch tube to be turned on and off, thereby controlling the second relay to be in a normally open state or a normally closed state. When the second relay is in a normally closed state, the positive and negative electrodes of the series-connected generating subcircuit 310 are connected.

[0065] In the embodiment of the present application, the second switch tube is also used to control the switch operation of the current. In one example, the second switch tube can also select a bipolar transistor (BJT). The second switch tube is connected to the control module 130 and the second relay respectively, and the second relay connects the positive and negative poles of the series power generation sub-circuit 310. When the control module 130 fails, the second switch tube is disconnected, the second relay is not activated, and the state is switched to a normally closed state. Since the second relay is connected between the positive and negative poles of the series power generation sub-circuit 310, at this time, the positive and negative poles of the series power generation sub-circuit 310 are connected. In this way, in the case of failure of the control module 130, the current loop of the series power generation sub-circuit can also remain connected to ensure the continued operation of the photovoltaic power generation system. In the embodiment of the present application, the bypass diode is replaced by the second switch tube and the second relay. Since the internal resistance of the relay is in the milliohm level, compared with the tube voltage drop of the Schottky diode, under the same current, the power consumption can be reduced by several times, which greatly reduces the heating and heating losses.

[0066] The following takes the case where the second switch tube is a bipolar transistor and the second relay is an electromagnetic relay as an example.

[0067] Figure 4 FIG. 1 is a schematic diagram of a photovoltaic shutdown control circuit according to another embodiment of the present application. Figure 4 As shown, in the embodiment of the present application, the second switch tube Q3 includes a second base b2, a second collector c2 and a second emitter e2, the second base b2 is connected to the control module 130, and the second emitter e2 is grounded (for example, through the negative pole PV-grounded of the photovoltaic component panel 200).

[0068] The second relay K2 includes a second common terminal 21, a second normally closed terminal 22, a second normally open terminal 23, a second power supply terminal positive electrode 24, and a second power supply terminal negative electrode 25. The second common terminal 21 is connected to the positive electrode OUT+ of the series power generation electronic circuit 310, the second normally closed terminal 22 is connected to the negative electrode OUT- of the series power generation electronic circuit 310, the second power supply terminal positive electrode 24 is connected to the positive electrode PV+ of the photovoltaic component panel 200, and the second power supply terminal negative electrode 25 is connected to the collector c2 of the second switch tube Q3;

[0069] When the second switch tube Q3 is disconnected, the second common terminal 21 and the second normally closed terminal 22 of the second relay K2 are closed, and the positive electrode OUT+ and the negative electrode OUT- of the series generating sub-circuit 310 are connected.

[0070] In the embodiment of the present application, if the control module 130 applies a forward bias voltage to the second base b2, a forward bias is formed at the junction of the second base b2 and the second emitter e2, which can significantly increase the current from the second collector c2 to the second emitter e2. When the current of the second base b2 exceeds the starting current, the second switch tube Q3 is turned on. After the second switch tube Q3 is turned on, the formed current flows into the second relay K2. The coil of the second relay K2 includes two ends, namely the second power supply end positive electrode 24 and the second power supply end negative electrode 25. The second power supply end negative electrode 25 is connected to the second collector c2 of the second switch tube Q3, and the second emitter e2 is grounded. When the current flows through the coil of the second relay K2, a magnetic field is generated. Due to the effect of electromagnetic induction, the generated magnetic field will attract the contacts, which are made of conductive materials and include a second normally closed end 22 and a second normally open end 23. When the power is not on, the second normally closed end 22 is in a closed state, and the second normally open end 23 is in an open state. When the coil is energized, the magnetic field will attract the contact, causing the second normally closed end 22 to be disconnected and the second normally open end 23 to be closed. Since the second normally closed end 22 is not connected to the path, when the second relay K2 is in the normally closed state, the bypass module is in the disconnected state. Therefore, in the case of failure of the control module 130, the voltage between the second base b2 and the second emitter e2 of the second switch tube Q3 is low, and there is not enough energy to push the electrons to the emitter e2, resulting in no electron flow, and the second switch tube Q3 is in the cut-off state, that is, the non-conducting state. At this time, the coil of the second relay K2 will not generate a magnetic field, and the contact will return to the second normally closed end 22. Since the second normally closed end 22 is connected to the negative pole OUT- of the series power generation sub-circuit, and the second common end 21 is connected to the positive pole OUT+ of the series power generation sub-circuit; at this time, when the second switch tube Q3 is not conducting, the second relay K2 can connect the positive pole OUT+ and the negative pole OUT- of the series power generation sub-circuit 310.

[0071] refer to Figure 3 and Figure 4In a specific embodiment of the present application, when the photovoltaic cut-off device enters normal operation, the control module 130 can first drive the second switch tube Q3 to connect the second power supply terminal negative electrode 25 of the second relay K2 to the reference ground, and the second power supply terminal positive electrode 24 of the second relay K2 is powered from the positive electrode PV+ of the photovoltaic module panel 200, and the state of the second relay K2 is switched, and the second common terminal 21 and the second normally closed terminal 22 are disconnected. Then, the control module 130 drives the field effect tube Q1 again to connect the positive electrode PV+ of the photovoltaic module panel 200 to the positive electrode OUT+ of the series power generation electronic circuit 310, and connect this photovoltaic module panel 200 to the series power generation unit. Then, the control module 130 drives the first switch tube Q2 to connect the first power supply terminal negative electrode 15 of the first relay K1 to the reference ground, and the first power supply terminal positive electrode 14 of the first relay K1 is powered from the positive electrode OUT+ of the series power generation electronic circuit 310, and the state of the first relay K1 is switched, and the first common terminal 11 and the first normally open terminal 13 are turned on. Then, the control module 130 stops driving the field effect transistor Q1, and at this time, the positive electrode PV+ of the photovoltaic module panel 200 is still connected to the positive electrode OUT+ of the series power generation electronic circuit 310. In this way, the field effect transistor Q1 will not be in a working state for a long time, which greatly prolongs its service life. Moreover, when the on-state internal resistance of the relay is 3-8mΩ, which is similar to the internal resistance of the low-resistance field effect transistor Q1, the service life can be as long as 15-25 years, which can improve the stability of the photovoltaic power generation system.

[0072] When the photovoltaic shut-off device fails, the field effect tube Q1, the first switch tube Q2 and the second switch tube Q3 all lose the drive of the control module 130. At this time, the field effect tube Q1 is in the disconnected state, and the first switch module 110 is disconnected; the first common terminal 11 and the first normally open terminal 13 of the first relay K1 are in the disconnected state, and the second switch module is also not turned on. However, the second common terminal 21 and the second normally closed terminal 23 of the second relay K2 are in the closed state, and the positive pole OUT+ and the negative pole OUT- of the series power generation sub-circuit 310 can be connected. In this way, the bypass diode is replaced by the second relay K2 and the second switch tube Q3, and the internal resistance of the relay in the milliohm level is compared with the tube voltage drop of the Schottky diode. Under the same current, the power is reduced by several times, which greatly reduces the heat generation and power generation losses.

[0073] The embodiment of the present application also provides a photovoltaic shutdown device, including the photovoltaic shutdown device control circuit mentioned above.

[0074] In addition, based on the above, if Figure 5As shown, the embodiment of the present application also provides a photovoltaic power generation system. The photovoltaic power generation system may include a plurality of the above-mentioned photovoltaic shut-off devices 100, a plurality of photovoltaic assembly panels 200, and a series power generation unit 300. Each photovoltaic assembly panel 200 is connected to the first end of the corresponding photovoltaic shut-off device 100, and the series power generation unit 300 includes a plurality of series power generation electronic circuits 310, each series power generation electronic circuit 310 corresponds to a photovoltaic assembly panel 200, and is connected to the second end of the corresponding photovoltaic shut-off device 100, and is used to connect a plurality of photovoltaic assembly panels 200 in series to transmit the generated direct current to the inverter circuit.

[0075] In an embodiment of the present application, a photovoltaic power generation system may include a plurality of photovoltaic circuit breakers 100, a plurality of photovoltaic assembly panels 200, and a series power generation unit 300. The photovoltaic circuit breaker 100 is a safety switch device used in a DC photovoltaic power generation system, and a power generation system can be obtained by connecting a plurality of photovoltaic assembly panels 200 in series. When sunlight shines on the photovoltaic assembly panel 100, the photovoltaic assembly panel can generate direct current, such as generating 50V direct current, then the positive pole PV+ of the photovoltaic assembly panel 200 is 50V, and the negative pole PV- is the reference ground. Each photovoltaic circuit breaker 100 corresponds to a photovoltaic assembly panel 200 and a series power generation electronic circuit 310. A plurality of series power generation electronic circuits 310 are connected in series to form a series power generation unit 300, and a plurality of photovoltaic assembly panels can be connected in series to transmit the generated direct current to the inverter circuit, and the inverter circuit further converts the direct current into alternating current for grid-connected power generation.

[0076] In the embodiment of the present application, the positive electrode OUT+ of each series-connected power generation sub-circuit 310 is connected to the negative electrode OUT- of the series-connected power generation sub-circuit 310 of the previous stage, and the negative electrode OUT- is connected to the positive electrode OUT+ of the series-connected power generation sub-circuit 310 of the next stage. That is, the negative electrode OUT- of the previous stage series-connected power generation sub-circuit 310 in the series-connected power generation unit 300 is connected to the positive electrode OUT+ of the current series-connected power generation sub-circuit 310. The series-connected power generation sub-circuit 310 is connected to the second end of the photovoltaic shut-off device 100, and the first end of the photovoltaic shut-off device 100 is connected to the corresponding photovoltaic assembly panel 200. In this way, the photovoltaic shut-off devices 100 can be connected in series, thereby connecting multiple photovoltaic assembly panels 200 in series. The positive electrode OUT+ of the first stage series-connected power generation sub-circuit 310 and the negative electrode OUT- of the last stage series-connected power generation sub-circuit 310 are respectively connected to the inverter circuit, so that the direct current generated by the series-connected power generation unit 300 can be transmitted to the inverter circuit.

[0077] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0078] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A photovoltaic shutdown control circuit, characterized in that: It includes a first switch module, a second switch module and a control module, wherein the control module is connected to the first switch module and the second switch module respectively, and the first switch module and the second switch module are connected between the photovoltaic component panel and the series power generation electronic circuit; the series power generation electronic circuit includes a wire connecting the photovoltaic component panel and the inverter circuit; The first switch module includes a transistor, which is used to be turned on or off under the control of the control module; The control module is used to control the second switch module to turn on and turn off the transistor of the first switch module after controlling the transistor of the first switch module to turn on to connect the photovoltaic component panel and the series power generation electronic circuit, so that the photovoltaic component panel and the series power generation electronic circuit are connected through the second switch module.

2. The photovoltaic shutoff control circuit according to claim 1, characterized in that: The second switch module includes a first switch tube and a first relay; The first switch tube is connected to the control module and the first relay respectively, and the first relay is also connected to the photovoltaic component panel and the series power generation electronic circuit; Among them, the control module controls the first switch tube to be turned on and off, and then controls the first relay to be in a normally open state or a normally closed state. When the first relay is in the normally open state, the photovoltaic component panel and the series power generation circuit are connected through the first relay.

3. The photovoltaic shutoff control circuit according to claim 2, characterized in that: The first switch tube includes a first base, a first collector and a first emitter, the first base is connected to the control module, and the first emitter is grounded; The first relay comprises a first common terminal, a first normally closed terminal, a first normally open terminal, a first positive power supply terminal and a first negative power supply terminal, the first common terminal and the first positive power supply terminal are connected to the positive electrode of the series power generation electronic circuit, the first normally open terminal is connected to the positive electrode of the photovoltaic module panel, and the first negative power supply terminal is connected to the first collector of the first switch tube; Among them, when the first switch tube is turned on, the first common end and the first normally open end of the first relay are closed, so that the photovoltaic component panel is connected to the series power generation electronic circuit.

4. The photovoltaic shutoff control circuit according to claim 2, characterized in that: A difference between an on-state internal resistance of the first relay and an internal resistance of the transistor is within a preset range.

5. The photovoltaic shutdown control circuit according to any one of claims 1 to 4, characterized in that: It also includes a bypass module, the two ends of which are respectively connected to the positive electrode and the negative electrode of the series power generation sub-circuit, and the bypass module is used to connect the positive electrode and the negative electrode of the series power generation sub-circuit when the first switch module and the second switch module are turned off.

6. The photovoltaic shutoff control circuit according to claim 5, characterized in that: The bypass module includes a second switch tube and a second relay; The second switch tube is connected to the control module and the second relay respectively, and the second relay is also connected to the positive electrode and the negative electrode of the series generating electronic circuit; Among them, the control module controls the second switch tube to be turned on and off, and then controls the second relay to be in a normally open state or a normally closed state. When the second relay is in a normally closed state, the positive and negative electrodes of the series generating subcircuit are connected.

7. The photovoltaic shutoff control circuit according to claim 6, characterized in that: The second switch tube comprises a second base, a second collector and a second emitter, the second base is connected to the control module, and the second emitter is grounded; The second relay includes a second common terminal, a second normally closed terminal, a second normally open terminal, a second positive power supply terminal and a second negative power supply terminal, the second common terminal is connected to the positive electrode of the series power generation electronic circuit, the second normally closed terminal is connected to the negative electrode of the series power generation electronic circuit, the second positive power supply terminal is connected to the positive electrode of the photovoltaic module panel, and the second negative power supply terminal is connected to the collector of the second switch tube; Wherein, when the second switch tube is disconnected, the second common terminal and the second normally closed terminal of the second relay are closed, and the positive electrode and the negative electrode of the series power generation sub-circuit are connected.

8. A photovoltaic shut-off device, characterized in that: The method comprises a photovoltaic shut-off control circuit according to any one of claims 1 to 7.

9. A photovoltaic power generation system, characterized in that: include: A plurality of photovoltaic shut-off devices according to claim 8; A plurality of photovoltaic assembly panels, each photovoltaic assembly panel is connected to a first end of a corresponding photovoltaic disconnector; The series power generation unit includes multiple series power generation sub-circuits, each of which corresponds to a photovoltaic component panel and is connected to the second end of the corresponding photovoltaic circuit breaker, and is used to connect the multiple photovoltaic component panels in series to transmit the generated direct current to the inverter circuit.

10. The photovoltaic power generation system according to claim 9, characterized in that: The positive electrode of each series-connected power generation sub-circuit is connected to the negative electrode of the series-connected power generation sub-circuit of the previous stage, and the negative electrode is connected to the positive electrode of the series-connected power generation sub-circuit of the next stage.

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