A circuit with lightning protection and photovoltaic storage inverter

Abstract

The present application discloses a circuit with lightning protection and a photovoltaic storage inverter. The circuit with lightning protection includes: a lightning protection sub-circuit and a target circuit; the first end of the lightning protection sub-circuit is electrically connected to the target circuit, and the second end of the lightning protection sub-circuit is electrically connected to the ground, and is used to transmit the target voltage to the ground when the target circuit is impacted by the target voltage. The target circuit includes at least one circuit in the photovoltaic storage inverter, and the target voltage includes at least one of a peak voltage and a surge voltage. The embodiment of the present application can prevent the target circuit from damaging the devices in the target circuit when a peak voltage and a surge voltage are generated, thereby achieving the lightning protection effect of the target circuit.

Description

Technical Field

[0001] The present application belongs to the field of power electronics technology, and in particular relates to a circuit with lightning protection and a photovoltaic storage inverter. Background Art

[0002] In the photovoltaic storage inverter system, in thunderstorm weather, the photovoltaic circuit board is easily struck by lightning, resulting in abnormal current and even damage to the circuit board.

[0003] Therefore, how to design a circuit with lightning protection function for the photovoltaic storage inverter has become a hot issue in the current research on photovoltaic storage inverter system technology. Utility Model Content

[0004] The embodiments of the present application provide a circuit and a photovoltaic storage inverter with lightning protection, which can prevent the devices in the target circuit from being damaged when a peak voltage and a surge voltage are generated in the target circuit, thereby achieving a lightning protection effect for the target circuit.

[0005] In the first aspect, an embodiment of the present application provides a circuit with lightning protection, and the circuit with lightning protection includes: a lightning protection sub-circuit and a target circuit; the first end of the lightning protection sub-circuit is electrically connected to the target circuit, and the second end of the lightning protection sub-circuit is electrically connected to the earth, and is used for transmitting the target voltage to the earth when the target circuit is impacted by the target voltage, and the target circuit includes at least one circuit in a photovoltaic storage inverter, and the target voltage includes at least one of a peak voltage and a surge voltage.

[0006] According to the implementation scheme of the first aspect of the present application, the target circuit is electrically connected to the bus input terminal, and the target circuit includes at least one of the insulation impedance detection circuit, the bus current detection circuit and the bus current protection circuit in the photovoltaic storage inverter. The insulation impedance detection circuit is used to detect the insulation impedance of the bus input terminal to the earth, the bus current detection circuit is used to detect the current at the bus input terminal, and the bus current protection circuit is used to output a level signal indicating whether the photovoltaic storage inverter is faulty according to the magnitude of the current at the bus input terminal. The photovoltaic storage inverter includes the target circuit; the first end of the lightning protection sub-circuit is electrically connected to the bus input terminal, and the second end of the lightning protection sub-circuit is electrically connected to the earth. The lightning protection sub-circuit is used to transmit the target voltage to the earth when the target voltage is input to the bus input terminal.

[0007] According to any of the aforementioned embodiments of the first aspect of the present application, the bus input end includes the bus positive pole, the bus negative pole and the bus midpoint, and the lightning protection sub-circuit includes N surge protectors, N≥3; there is at least one surge protector between the bus positive pole and the ground; there is at least one surge protector between the bus negative pole and the ground; there is at least one surge protector between the bus midpoint and the ground.

[0008] According to any of the aforementioned embodiments of the first aspect of the present application, N surge protectors include: a first surge protector, wherein the first end of the first surge protector is electrically connected to the positive pole of the bus, and the second end of the first surge protector is electrically connected to the midpoint of the bus; a second surge protector, wherein the first end of the second surge protector is electrically connected to the negative pole of the bus, and the second end of the second surge protector is electrically connected to the second end of the first surge protector and the midpoint of the bus; and a third surge protector, wherein the first end of the third surge protector is electrically connected to the midpoint of the bus, the second end of the first surge protector and the second end of the second surge protector, and the second end of the third surge protector is electrically connected to the ground.

[0009] According to any of the aforementioned embodiments of the first aspect of the present application, the lightning protection sub-circuit also includes: at least one gas discharge tube, and the second end of the first surge protector, the second end of the second surge protector and the second end of the third surge protector are all connected to the ground through the gas discharge tube.

[0010] According to any of the aforementioned embodiments of the first aspect of the present application, the lightning protection sub-circuit also includes: a lightning protection status feedback branch, the lightning protection status feedback branch is electrically connected to at least one surge protector, the first end of the lightning protection status feedback branch is electrically connected to the signal input end, and the second end of the lightning protection status feedback branch is electrically connected to the ground end; when the target voltage passes through the surge protector, the lightning protection status feedback branch outputs a first level, and when the target voltage does not pass through the surge protector, the lightning protection status feedback branch outputs a second level.

[0011] According to any of the aforementioned embodiments of the first aspect of the present application, the lightning protection status feedback branch includes: a pull-up module, a first end of the pull-up module is electrically connected to the signal input end, and is used to pull up the input signal of the signal input end to a high level; a buffer module, a first end of the buffer module is electrically connected to the first end of the pull-up module and the signal input end, respectively, and the second end of the buffer module is the output end.

[0012] According to any of the aforementioned embodiments of the first aspect of the present application, the circuit with lightning protection also includes: a filtering module, a first end of the filtering module is electrically connected to the positive pole of the bus, and a second end of the filtering module is electrically connected to the earth; and / or, a first end of the filtering module is electrically connected to the negative pole of the bus, and a second end of the filtering module is electrically connected to the earth.

[0013] According to any of the aforementioned embodiments of the first aspect of the present application, the target circuit includes a Hall detection circuit, a first end of the Hall detection circuit is electrically connected to the first phase, the second phase and the third phase of the photovoltaic storage inverter, a second end of the Hall detection sub-circuit is electrically connected to the digital processor, and the Hall detection sub-circuit is used to detect the leakage current of the first phase, the second phase and the third phase; a first end of the lightning protection sub-circuit is electrically connected to the first phase, the second phase and the third phase, a second end of the lightning protection sub-circuit is electrically connected to the ground, and the lightning protection sub-circuit is used to transmit the target voltage to the ground when the target voltage is input to the first phase, the second phase and the third phase.

[0014] In a second aspect, an embodiment of the present application provides a photovoltaic storage inverter, which includes a circuit with lightning protection as in the first aspect.

[0015] The circuit with lightning protection and the photovoltaic storage inverter of the embodiment of the present application, the circuit with lightning protection includes a lightning protection sub-circuit and a target circuit. In thunder and lightning weather, when the target circuit is easily struck by lightning, spike voltage and / or surge voltage will often be generated, resulting in a high probability of circuit damage. The first end of the lightning protection sub-circuit of the present application is electrically connected to the target circuit, and the second end is connected to the ground. When at least one of the spike voltage and surge voltage is input to the target circuit, it can be transmitted to the ground, so that the spike voltage and surge voltage will not damage the devices in the target circuit, thereby achieving a lightning protection effect on the target circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 This is a schematic diagram of a circuit structure with a lightning protection circuit provided in an embodiment of the present application;

[0018] Figure 2 This is another schematic diagram of a circuit structure with a lightning protection circuit provided in an embodiment of the present application;

[0019] Figure 3 This is a schematic diagram of a circuit structure of a lightning protection sub-circuit provided in an embodiment of the present application;

[0020] Figure 4 This is another circuit structure schematic diagram of the lightning protection sub-circuit provided in the embodiment of the present application;

[0021] Figure 5 This is another circuit structure schematic diagram of the lightning protection sub-circuit provided in the embodiment of the present application;

[0022] Figure 6This is another circuit structure schematic diagram of the lightning protection sub-circuit provided in the embodiment of the present application;

[0023] Figure 7 This is another circuit structure schematic diagram of the lightning protection sub-circuit provided in the embodiment of the present application;

[0024] Figure 8 This is a circuit structure diagram of a lightning protection state feedback branch provided in an embodiment of the present application;

[0025] Fig. 9 This is a circuit structure diagram of an insulation impedance detection circuit provided in an embodiment of the present application;

[0026] Fig.10 This is a circuit structure diagram of a bus current detection circuit provided in an embodiment of the present application;

[0027] Fig.11 This is a circuit structure diagram of a bus current protection circuit provided in an embodiment of the present application;

[0028] Fig.12 This is another circuit structure schematic diagram of a lightning protection circuit provided in an embodiment of the present application;

[0029] Fig.13 This is another circuit structure schematic diagram of a lightning protection circuit provided in an embodiment of the present application;

[0030] Fig.14 It is a circuit structure schematic diagram of the Hall detection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0032] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" 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 includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0033] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0034] In the embodiments of the present application, the term “electrically connected” may refer to a direct electrical connection between two components, or may refer to an electrical connection between two components via one or more other components.

[0035] It is obvious to those skilled in the art that various modifications and changes can be made in the present application without departing from the spirit or scope of the present application. Therefore, the present application is intended to cover modifications and changes of the present application that fall within the scope of the corresponding claims (technical solutions for protection) and their equivalents. It should be noted that the implementation methods provided in the embodiments of the present application can be combined with each other without contradiction.

[0036] In order to solve the related technical problems, the embodiments of the present application provide a circuit with lightning protection and a photovoltaic storage inverter. The circuit with lightning protection in the embodiments of the present application is first introduced below.

[0037] Figure 1 FIG. 1 is a schematic diagram showing a circuit structure of a lightning protection circuit provided by an embodiment of the present application. Figure 1 As shown, the circuit 100 with lightning protection may include a lightning protection sub-circuit 10 and a target circuit 20 .

[0038] The first end of the lightning protection sub-circuit 10 is electrically connected to the target circuit 20, and the second end of the lightning protection sub-circuit 10 is electrically connected to the earth PE, and is used to transmit the target voltage to the earth PE when the target circuit 20 is impacted by the target voltage. The target circuit 20 includes at least one circuit in the photovoltaic storage inverter, and the target voltage includes at least one of a peak voltage and a surge voltage.

[0039] The circuit 100 with lightning protection of the embodiment of the present application includes a lightning protection sub-circuit 10 and a target circuit 20. In thunder and lightning weather, when the target circuit 20 is easily struck by lightning, a spike voltage and / or a surge voltage is often generated, resulting in a high probability of circuit damage. The first end of the lightning protection sub-circuit 10 of the present application is electrically connected to the target circuit 20, and the second end is connected to the earth PE. When at least one of the spike voltage and the surge voltage is input to the target circuit, it can be transmitted to the earth PE, so that the spike voltage and the surge voltage will not damage the devices in the target circuit 20, thereby achieving a lightning protection effect on the target circuit 20.

[0040] In some embodiments, the target circuit 20 is electrically connected to the bus input terminal, and the target circuit 20 includes at least one of an insulation impedance detection circuit, a bus current detection circuit, and a bus current protection circuit in the photovoltaic inverter. For the specific structures of the insulation impedance detection circuit, the bus current detection circuit, and the bus current protection circuit, see Fig. 9 , 10 , 11 and 12 parts are explained in detail.

[0041] Among them, the insulation impedance detection circuit is used to detect the insulation impedance of the bus input terminal to the ground, the bus current detection circuit is used to detect the current at the bus input terminal, and the bus current protection circuit is used to output a level signal indicating whether the photovoltaic storage inverter is faulty according to the size of the current at the bus input terminal. The photovoltaic storage inverter includes a target circuit 20.

[0042] The first end of the lightning protection sub-circuit 10 is electrically connected to the bus input end, and the second end of the lightning protection sub-circuit is electrically connected to the earth PE. The lightning protection sub-circuit 10 is used to transmit the target voltage to the earth PE when the target voltage is input to the bus input end.

[0043] When there are multiple target circuits, the multiple target circuits can share one lightning protection sub-circuit, or a lightning protection sub-circuit can be set for each target circuit. Multiple target circuits can share one lightning protection sub-circuit, which can save costs. Each target circuit is set with a lightning protection sub-circuit, which can improve the lightning protection effect of the target circuit.

[0044] Figure 2 is another circuit structure schematic diagram of a lightning protection circuit provided in an embodiment of the present application, such as Figure 2As shown, the bus input terminal includes a bus positive electrode BUS+, a bus negative electrode BUS- and a bus midpoint BUSN. The bus input terminal is electrically connected to the lightning protection sub-circuit 10 and the target circuit 20 respectively.

[0045] In some embodiments, the circuit with lightning protection further includes: a filtering module 30 .

[0046] The filter module 30, the first end of the filter module 30 is electrically connected to the bus positive pole BUS+, and the second end of the filter module 30 is electrically connected to the earth PE; and / or, the first end of the filter module 30 is electrically connected to the bus negative pole BUS-, and the second end of the filter module 30 is electrically connected to the earth PE.

[0047] The filter module 30 can filter the bus input, eliminate common-mode interference, and protect the subsequent circuit.

[0048] exist Figure 2 In this example, taking the filter module 30 including the first filter module 301 and the second filter module 302 as an example, the first end of the first filter module 301 is electrically connected to the positive pole of the bus BUS+, and the second end of the first filter module 301 is electrically connected to the earth PE; the first end of the second filter module 302 is electrically connected to the negative pole of the bus BUS-, and the second end of the second filter module 302 is electrically connected to the earth PE.

[0049] For example, the first filter module 301 may be a first safety capacitor C1, and the second filter module 302 may be a second safety capacitor C2. After the safety capacitor fails, it will not cause electric shock and will not endanger personal safety.

[0050] In some embodiments, the lightning protection subcircuit includes N surge protectors, N≥3; at least one surge protector is provided between the bus positive pole BUS+ and the earth PE; at least one surge protector is provided between the bus negative pole BUS- and the earth PE; at least one surge protector is provided between the bus midpoint BUSN and the earth PE. The surge protector may include a lightning arrester.

[0051] like Figure 3 As shown, Figure 3 This is a schematic diagram of a circuit structure of a lightning protection sub-circuit provided in an embodiment of the present application; Figure 3 For example, there is a surge protector between the bus positive pole BUS+, the bus negative pole BUS- and the bus midpoint BUSN and the earth PE. The N surge protectors include a first surge protector F1, a second surge protector F2 and a third surge protector F3.

[0052] The first end of the first surge protector F1 is electrically connected to the bus positive pole BUS+; the first end of the second surge protector F2 is electrically connected to the bus midpoint BUSN, the first end of the third surge protector F3 is electrically connected to the bus negative pole BUS-, and the second ends of the first surge protector F1, the second surge protector F2 and the third surge protector F3 are all electrically connected to the earth PE.

[0053] This is not intended to limit the present application, and the bus positive pole BUS+, bus negative pole BUS-, bus midpoint BUSN and earth PE may also have multiple surge protectors. Figure 4 , Figure 5 and Figure 6 .

[0054] It should be noted that although the present application only takes the circuit structure of the lightning protection sub-circuit including a surge protector as an example, technical personnel in this field can design the structure of the lightning protection sub-circuit into other forms based on the present application, and the lightning protection sub-circuit in the embodiment of the present application may also include other circuit structures with lightning protection functions.

[0055] Figure 4 is another circuit structure diagram of the lightning protection sub-circuit provided in the embodiment of the present application, such as Figure 4 As shown, the first end of the first surge protector F1 is electrically connected to the bus positive pole BUS+, and the second end of the first surge protector F1 is electrically connected to the bus midpoint BUSN; the first end of the second surge protector F2 is electrically connected to the bus negative pole BUS-, and the second end of the second surge protector F2 is electrically connected to the second end of the first surge protector F1 and the bus midpoint BUSN; the first end of the third surge protector F3 is electrically connected to the bus midpoint BUSN, the second end of the first surge protector F1 and the second end of the second surge protector F2, and the second end of the third surge protector F3 is electrically connected to the earth PE.

[0056] Figure 4 By using three surge protectors, there are two surge protectors from the bus positive pole BUS+ and the bus negative pole BUS- to the ground, which improves the voltage resistance of the bus positive pole BUS+ and the bus negative pole BUS-. The bus midpoint BUSN is also guaranteed to have a surge protector to achieve lightning protection function.

[0057] Figure 5 Another circuit structure diagram of the lightning protection sub-circuit provided in the embodiment of the present application is as follows: Figure 5As shown, the N surge protectors include a first surge protector F1, a second surge protector F2, a third surge protector F3 and a fourth surge protector F4. The four surge protectors are connected in parallel first and then in series, so that there are two surge protectors between the bus positive pole BUS+, the bus negative pole BUS- and the bus midpoint BUSN and the earth PE. While increasing the withstand voltage value of each branch, not too many surge protectors are used, reducing costs.

[0058] Figure 6 is another circuit structure diagram of the lightning protection sub-circuit provided in the embodiment of the present application, such as Figure 6 As shown, the lightning protection sub-circuit 10 further includes: at least one gas discharge tube Q, and the second end of the first surge protector F1, the second end of the second surge protector F2 and the second end of the third surge protector F3 are all connected to the earth PE through the gas discharge tube Q. Figure 6 Taking the lightning protection sub-circuit 10 including a gas discharge tube Q as an example, this is not intended to limit the present application.

[0059] Gas discharge tube refers to a lightning arrester or antenna switch tube used for overvoltage protection. There are two or more electrodes in the tube, which is filled with a certain amount of inert gas. Gas discharge tube is a gap-type lightning protection element, commonly used in lightning protection of communication systems.

[0060] By adding the gas discharge tube Q, the lightning protection capability of the lightning protection sub-circuit 10 can be further improved.

[0061] Figure 7 is another circuit structure diagram of the lightning protection sub-circuit provided in the embodiment of the present application, such as Figure 7 As shown, in some embodiments, the lightning protection sub-circuit 10 further includes: a lightning protection state feedback branch L, the lightning protection state feedback branch L is electrically connected to at least one surge protector, the first end of the lightning protection state feedback branch L is electrically connected to the signal input end, and the second end of the lightning protection state feedback branch L is electrically connected to the ground end GND. The lightning protection state feedback branch L is used to feedback the state of the connected surge protector.

[0062] Figure 7 Taking the lightning protection state feedback branch L connected to each surge protector as an example, this is not intended to limit the present application, and multiple lightning protection state feedback branches may also be provided, each lightning protection state feedback branch being electrically connected to one of the surge protectors. In this way, each lightning protection state feedback branch can feedback the state of the connected surge protector.

[0063] When the target voltage passes through the surge protector, the lightning protection state feedback branch L outputs a first level. When the target voltage does not pass through the surge protector, the lightning protection state feedback branch L outputs a second level.

[0064] Exemplarily, when the target circuit 20 is struck by lightning, the target circuit 20 will generate at least one of a spike voltage and a surge voltage. At this time, the surge protector in the lightning protection subcircuit 10 will be turned on to transmit the spike voltage and surge voltage to the earth PE. When the surge protector passes the spike voltage and / or surge voltage, the surge protector controls the connection of the lightning protection state feedback branch L to be disconnected, and the lightning protection state feedback branch outputs a first level. When the surge protector does not pass the spike voltage and / or surge voltage, the connection of the lightning protection state feedback branch L is normal, and the lightning protection state feedback branch L is connected to the ground terminal GND through the connected surge protector, and outputs a second level.

[0065] Figure 8 is a circuit structure diagram of a lightning protection state feedback branch provided in an embodiment of the present application, such as Figure 8 As shown, in some embodiments, the lightning protection state feedback branch L may include: a pull-up module 810 and a buffer module 820 .

[0066] The first end of the pull-up module 810 is electrically connected to the signal input end, and is used to pull up the input signal of the signal input end to a high level; the first end of the buffer module 820 is electrically connected to the first end of the pull-up module 810 and the signal input end respectively, and the second end of the buffer module 820 is the output end.

[0067] In this embodiment, the first level is a high level, and the second level is a low level. When the surge protector is not struck by lightning, the lightning protection state feedback branch L is normally connected to the surge protector, the lightning protection state feedback branch L is connected to the ground terminal GND, and a low level is output; when the surge protector is struck by lightning, the surge protector is turned on, and the lightning protection state feedback branch L connected to the turned-on surge protector is controlled to be disconnected. The lightning protection state feedback branch L is disconnected and cannot be connected to the ground terminal GND, and is pulled up to a high potential by the pull-up module 810, and a high level is output. This realizes the function of feedback of the state of the connected surge protector.

[0068] exist Figure 8 In this example, the pull-up module 810 includes a power supply terminal 5VA and a resistor R6. The power supply terminal 5VA and the resistor R6 are connected in series to pull up the lightning protection feedback signal to a high level when the lightning protection state feedback branch is not connected to the ground terminal GND due to lightning strike.

[0069] The buffer module 820 includes a Schmitt buffer trigger, which is electrically connected to the signal input terminal and is used to buffer the signal.

[0070] The lightning protection state feedback branch may further include a first diode D1, a second diode D2, a third diode D3, resistors R3-R7, capacitors C3-C7 and an inductor I1.

[0071] The first end of the capacitor C3 is electrically connected to the second end of the resistor R6 and the signal input end, the second end of the capacitor C3 is electrically connected to the ground terminal GND, and the capacitor C3 is used for filtering; the first end of the resistor R3 is electrically connected to the first end of the capacitor C3, the second end of the resistor R3 is electrically connected to the first end of the capacitor C4, and the resistor R3 is used for current limiting; the second end of the capacitor C4 is electrically connected to the ground terminal GND, and the capacitor C4 is used for filtering.

[0072] The anode of the first diode D1 is electrically connected to the ground terminal, the cathode of the first diode D1 is electrically connected to the anode of the second diode D2 and the second end of the resistor R3, the cathode of the second diode D2 is electrically connected to the power supply terminal 5VA, and the first diode D1 and the second diode D2 are used to protect the lightning protection sub-circuit.

[0073] An anode of the third diode D3 is electrically connected to the second end of the resistor R3 , and a cathode of the third diode D3 is electrically connected to the resistor R4 . The third diode D3 is used to prevent reverse connection.

[0074] The second end of the resistor R4 is electrically connected to the first end of the Schmitt buffer trigger for current limiting. The capacitor C5 and the resistor R7 are connected in parallel between the second end of the resistor R4 and the ground terminal GND, and the capacitor C5 and the resistor R7 are used for filtering.

[0075] The inductor l1 is connected in series between the power supply terminal 5VA and the Schmitt trigger, the capacitor C7 is connected in series between the ground terminal and the Schmitt trigger, the resistor R5 and the capacitor C6 are connected in series between the Schmitt trigger and the ground terminal GND, and the second end of the resistor R5 is the output end.

[0076] Fig. 9 is a circuit structure diagram of an insulation impedance detection circuit provided in an embodiment of the present application, such as Fig. 9 As shown, the target circuit 20 includes an insulation impedance detection circuit. In the insulation impedance detection circuit, the bus positive electrode BUS+ and the bus negative electrode BUS- are connected to the ground with resistors respectively, wherein RPX and RPN are the insulation impedance of the bus input end to the ground, that is, the resistance value that we can obtain through calculation.

[0077] Among them, resistance values ​​R8-R15 are known resistance values ​​in the circuit, R11 and R12 are disturbance resistors, whose resistance values ​​are smaller than those of other resistors, and K1 and K2 are relays. The digital processor of the whole machine sends driving signals to the two relays K1 and K2 respectively to drive the two relays to close and open, and the two relays will not be opened and closed at the same time.

[0078] When K1 is closed and K2 is open, the bus positive pole BUS+ disturbance resistor R11 is connected to the circuit; when K1 is open and K2 is closed, the bus negative pole BUS- disturbance resistor R12 is connected to the circuit; since the resistance values ​​of R11 and R12 are known, two equations are listed according to the principle of resistor voltage division, RPX and RPN are unknowns, that is, the values ​​of RPX and RPN can be obtained by solving the set of equations.

[0079] When the target circuit 20 is an insulation impedance detection circuit, the lightning protection sub-circuit 10 can effectively prevent natural factors such as lightning from damaging the insulation impedance detection circuit and ensure its stable operation.

[0080] Fig.10 is a circuit structure diagram of a bus current detection circuit provided in an embodiment of the present application, such as Fig.10 As shown, the target circuit 20 may include a bus current detection circuit. In the bus current detection circuit, a Hall current detection circuit is used. The Hall device has the characteristics of primary and secondary isolation, high detection accuracy, strong anti-interference, and simple use. The bus input of the photovoltaic storage inverter is converted into a voltage signal through the Hall, and output to the bus current protection circuit through the operational amplifier. Bus current protection circuit see Fig.11 Since the Hall sensor has zero-point drift, which will lead to detection accuracy deviation, the photovoltaic storage inverter needs to check and correct the current zero drift when it is powered on for the first time.

[0081] Fig.11 is a circuit structure diagram of a bus current protection circuit provided in an embodiment of the present application, such as Fig.11 As shown in the figure, in the bus current protection circuit, because the voltage input to the digital processor (DSP) needs to be between 0 and 3.3V, the DC current is forward biased by a certain voltage and outputs an analog signal to the digital processor (DSP) through a voltage follower and RC filtering. At the same time, the biased signal is compared with the set high reference voltage and low reference voltage, and a high-level normal signal or a low-level level signal is output to the DSP. If the DSP receives the level signal, it will make a corresponding fault protection control strategy to protect the photovoltaic storage inverter system.

[0082] Fig.12 is another circuit structure diagram of a lightning protection circuit provided in an embodiment of the present application, such as Fig.12 As shown, in some embodiments, the target circuit 20 is composed of a bus current detection circuit and a bus current protection circuit connected in series. The lightning protection sub-circuit 10 can implement lightning protection for the target circuit 20.

[0083] based on Fig.12The embodiment of the present application is used to protect the system circuit of the photovoltaic storage inverter system when the busbar is overcurrent and in harsh working environments such as lightning, thereby reducing the failure rate of the system. In addition, the circuit topology is simple and has few components, which reduces the PCB area and the cost of circuit design.

[0084] In some embodiments, the target circuit 20 includes a Hall detection circuit, the first end of the Hall detection circuit is electrically connected to the first phase L1, the second phase L2 and the third phase L3 of the photovoltaic storage inverter, the second end of the Hall detection subcircuit is electrically connected to the digital processor, and the Hall detection subcircuit is used to detect the leakage current of the first phase L1, the second phase L2 and the third phase L3; the specific structure of the Hall detection circuit is shown in Fig.14 .

[0085] Fig.13 is another circuit structure diagram of a lightning protection circuit provided in an embodiment of the present application, such as Fig.13 As shown, the first end of the lightning protection sub-circuit 10 is electrically connected to the first phase L1, the second phase L2 and the third phase L3 respectively, and the second end of the lightning protection sub-circuit is electrically connected to the earth PE. The lightning protection sub-circuit 10 is used to transmit the target voltage to the earth PE when the target voltage is input to the first phase L1, the second phase L2 and the third phase L3.

[0086] The Hall detection circuit is also called a leakage current detection circuit. The embodiment of the present application provides a leakage current detection circuit with a lightning protection function, which is used to protect the entire circuit of the photovoltaic storage inverter in harsh working environments such as lightning. The leakage current data can be detected by the leakage current sensor, and the change of the leakage current can be monitored by the detection control system to make timely processing. The safety capacitor circuit can also filter the grid input, eliminate common mode interference, and protect the subsequent circuit. There are fewer circuit components, which can reduce the PCB area and improve the system power density.

[0087] When the lightning protection sub-circuit 10 performs lightning protection on the Hall detection circuit, the connection method is different from the connection method when connecting the insulation impedance detection circuit. Other than that, the structure of the lightning protection sub-circuit 10 is the same. That is, there is at least one surge protector between the first phase L1 and the earth PE; there is at least one surge protector between the second phase L2 and the earth PE; there is at least one surge protector between the third phase L3 and the earth. In addition, the lightning protection sub-circuit 10 also has a lightning protection status feedback branch, which is used to feedback the function of the connected surge protector. For a structural schematic diagram of the lightning protection status feedback branch, see Figure 8 .

[0088] Fig.14 is a circuit structure diagram of a Hall detection circuit provided in an embodiment of the present application, such as Fig.14As shown, the leakage current of the first phase L1, the second phase L2 and the third phase L3 of the photovoltaic storage inverter is collected by the leakage current sensor, and a reference signal and an output signal are output based on the collected signals of the first phase L1, the second phase L2 and the third phase L3, which are converted into the current size we need. Fig.14 The capacitors in the circuit are used for filtering, and the resistors R2 and R3 are used for current limiting.

[0089] Exemplarily, the leakage current is the ratio of the output signal to the reference signal. The reference signal voltage is 1.5V, the output signal is 3V, and the leakage current is 2A.

[0090] The embodiment of the present application further provides a photovoltaic storage inverter, which includes the circuit with lightning protection provided by any of the above embodiments. The photovoltaic storage inverter can achieve lightning protection and prevent the generation of surge voltage and peak voltage.

[0091] It should be understood that the specific structures of the circuits provided in the drawings of the embodiments of the present application are merely examples and are not intended to limit the present application. In addition, the above embodiments provided in the present application may be combined with each other if there is no contradiction.

[0092] It should be clear that each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. According to the embodiments described above in this application, these embodiments do not describe all the details in detail, nor do they limit the application to only the specific embodiments described. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the application, so that technicians in the relevant technical field can make good use of the application and the modified use based on the application. The application is only limited by the claims and their full scope and equivalents.

[0093] Those skilled in the art should understand that the above embodiments are exemplary rather than restrictive. Different technical features appearing in different embodiments can be combined to achieve beneficial effects. Based on the study of the drawings, the specification and the claims, those skilled in the art should be able to understand and implement other variations of the disclosed embodiments. In the claims, the term "comprising" does not exclude other structures; the quantity involves "one" but does not exclude multiple; the terms "first" and "second" are used to indicate names rather than to indicate any specific order. Any figure marks in the claims should not be understood as limiting the scope of protection. The appearance of certain technical features in different dependent claims does not mean that these technical features cannot be combined to achieve beneficial effects.

Claims

1. A circuit with lightning protection, characterized in that: include: Lightning protection sub-circuit and target circuit; The first end of the lightning protection sub-circuit is electrically connected to the target circuit, and the second end of the lightning protection sub-circuit is electrically connected to the ground, and is used to transmit the target voltage to the ground when the target circuit is impacted by the target voltage. The target circuit includes at least one circuit in a photovoltaic storage inverter, and the target voltage includes at least one of a peak voltage and a surge voltage.

2. The circuit with lightning protection according to claim 1, characterized in that: The target circuit is electrically connected to the bus input terminal, and includes at least one of an insulation impedance detection circuit, a bus current detection circuit, and a bus current protection circuit in the photovoltaic storage inverter. The insulation impedance detection circuit is used to detect the insulation impedance of the bus input terminal to the earth, the bus current detection circuit is used to detect the current of the bus input terminal, and the bus current protection circuit is used to output a level signal indicating whether the photovoltaic storage inverter is faulty according to the magnitude of the current of the bus input terminal. The photovoltaic storage inverter includes the target circuit; The first end of the lightning protection subcircuit is electrically connected to the bus input end, and the second end of the lightning protection subcircuit is electrically connected to the ground. The lightning protection subcircuit is used to transmit the target voltage to the ground when the target voltage is input to the bus input end.

3. The circuit with lightning protection according to claim 2, characterized in that: The bus input end includes a bus positive pole, a bus negative pole and a bus midpoint, and the lightning protection subcircuit includes N surge protectors, N ≥ 3; There is at least one surge protector between the positive pole of the busbar and the ground; There is at least one surge protector between the negative pole of the busbar and the ground; There is at least one surge protector between the midpoint of the busbar and the ground.

4. The circuit with lightning protection according to claim 3, characterized in that: The N surge protectors include: a first surge protector, wherein a first end of the first surge protector is electrically connected to the positive electrode of the busbar, and a second end of the first surge protector is electrically connected to a midpoint of the busbar; a second surge protector, wherein a first end of the second surge protector is electrically connected to the negative pole of the busbar, and a second end of the second surge protector is electrically connected to the second end of the first surge protector and a midpoint of the busbar; A third surge protector, wherein a first end of the third surge protector is electrically connected to the busbar midpoint, a second end of the first surge protector and a second end of the second surge protector, and a second end of the third surge protector is electrically connected to the ground.

5. The circuit with lightning protection according to claim 4, characterized in that: The lightning protection sub-circuit also includes: At least one gas discharge tube, the second end of the first surge protector, the second end of the second surge protector and the second end of the third surge protector are all connected to the ground through the gas discharge tube.

6. The circuit with lightning protection according to claim 3, characterized in that: The lightning protection sub-circuit also includes: A lightning protection state feedback branch, wherein the lightning protection state feedback branch is electrically connected to at least one of the surge protectors, a first end of the lightning protection state feedback branch is electrically connected to a signal input end, and a second end of the lightning protection state feedback branch is electrically connected to a ground end; When the target voltage passes through the surge protector, the lightning protection state feedback branch outputs a first level, and when the target voltage does not pass through the surge protector, the lightning protection state feedback branch outputs a second level.

7. The circuit with lightning protection according to claim 6, characterized in that: The lightning protection status feedback branch comprises: A pull-up module, a first end of which is electrically connected to the signal input end, and is used to pull up the input signal of the signal input end to a high level; A buffer module, wherein a first end of the buffer module is electrically connected to a first end of the pull-up module and the signal input end respectively, and a second end of the buffer module is an output end.

8. The circuit with lightning protection according to claim 3, characterized in that: The circuit with lightning protection also includes: A filter module, wherein a first end of the filter module is electrically connected to the positive electrode of the busbar, and a second end of the filter module is electrically connected to the earth; And / or, a first end of the filter module is electrically connected to the negative pole of the busbar, and a second end of the filter module is electrically connected to the ground.

9. The circuit with lightning protection according to claim 1, characterized in that: The target circuit includes a Hall detection circuit, a first end of the Hall detection circuit is electrically connected to the first phase, the second phase and the third phase of the photovoltaic storage inverter respectively, a second end of the Hall detection circuit is electrically connected to the digital processor, and the Hall detection circuit is used to detect the leakage current of the first phase, the second phase and the third phase; The first end of the lightning protection sub-circuit is electrically connected to the first phase, the second phase and the third phase respectively, and the second end of the lightning protection sub-circuit is electrically connected to the ground. The lightning protection sub-circuit is used to transmit the target voltage to the ground when the target voltage is input to the first phase, the second phase and the third phase.

10. A photovoltaic energy storage inverter, characterized in that: The photovoltaic energy storage inverter comprises a circuit with lightning protection as described in any one of claims 1-9.

Images