Lightning protection circuit, power supply system and electric equipment

Abstract

The utility model provides a lightning protection circuit, a power supply system and electric equipment. The lightning protection circuit comprises a first piezoresistor, a second piezoresistor and a filter inductance unit, the first piezoresistor comprises a first end electrically connected with the first input end of the filter inductor unit and a second end electrically connected with the second input end of the filter inductor unit; the second piezoresistor comprises a first end electrically connected with the first output end of the filter inductor unit and a second end electrically connected with the second output end of the filter inductor unit; and the starting threshold voltage of the second piezoresistor is smaller than that of the first piezoresistor. Due to the fact that the residual voltage flowing out of the first piezoresistor is smaller than the input lightning stroke voltage, the starting threshold voltage of the second piezoresistor is smaller than that of the first piezoresistor, and the second piezoresistor can absorb the residual voltage flowing out of the first piezoresistor more reliably.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply, in particular to a lightning protection circuit, a power supply system and an electrical equipment. BACKGROUND

[0002] The lightning protection circuit is mainly used for preventing the input lightning strike voltage from flowing to the subsequent device or component in the power supply system, so as to protect the subsequent device or component.

[0003] In the conventional lightning protection circuit for lightning strike, a pressure sensitive resistor is usually used to achieve the lightning protection purpose. However, with the increasing requirement of lightning strike resistance, the conventional scheme can only absorb a certain lightning strike voltage with one pressure sensitive resistor, but when the input lightning strike voltage is too high, the residual voltage from the pressure sensitive resistor to the subsequent stage is still high, which can easily cause damage to the device or component in the subsequent stage, so that the power supply cannot work normally. CONTENT OF THE INVENTION

[0004] In view of the deficiencies in the prior art, the present application provides a lightning protection circuit, a power supply system and an electrical equipment.

[0005] In a first aspect, in one embodiment, the present application provides a lightning protection circuit, comprising:

[0006] a first pressure sensitive resistor, a second pressure sensitive resistor and a filter inductor unit;

[0007] The first pressure sensitive resistor comprises a first end electrically connected to a first input end of the filter inductor unit, and a second end electrically connected to a second input end of the filter inductor unit; the second pressure sensitive resistor comprises a first end electrically connected to a first output end of the filter inductor unit, and a second end electrically connected to a second output end of the filter inductor unit;

[0008] The starting threshold voltage of the second pressure sensitive resistor is less than that of the first pressure sensitive resistor.

[0009] In one embodiment, the lightning protection circuit further comprises:

[0010] a temperature fuse tube;

[0011] The temperature fuse tube comprises a first end electrically connected to the second end of the second pressure sensitive resistor, and a second end electrically connected to the second output end of the filter inductor unit.

[0012] The temperature fuse tube is used for sensing the temperature of the second pressure sensitive resistor and disconnecting when the temperature of the second pressure sensitive resistor exceeds a preset temperature.

[0013] In one embodiment, the release current of the second pressure sensitive resistor is less than that of the first pressure sensitive resistor.

[0014] The release current represents the energy release capability.

[0015] In one embodiment, the lightning protection circuit further comprises:

[0016] a third varistor and a fourth varistor;

[0017] a first end of the third varistor is electrically connected with a first end of the first varistor and a first input end of the filter inductor unit respectively, and a second end of the third varistor is grounded;

[0018] a first end of the fourth varistor is electrically connected with a second end of the first varistor and a second input end of the filter inductor unit respectively, and a second end of the third varistor is grounded.

[0019] In one embodiment, the lightning protection circuit further comprises:

[0020] a current limiting resistor;

[0021] a first end of the current limiting resistor is electrically connected with a second end of the third varistor and a second end of the fourth varistor respectively, and a second end of the current limiting resistor is grounded.

[0022] In one embodiment, the filter inductor unit comprises a first common mode inductor and a second common mode inductor;

[0023] a first input end of the first common mode inductor is electrically connected with a first end of the first varistor, a second input end of the first common mode inductor is electrically connected with a second end of the first varistor, a first output end of the first common mode inductor is electrically connected with a first input end of the second common mode inductor, and a second output end of the first common mode inductor is electrically connected with a second input end of the second common mode inductor;

[0024] a first output end of the second common mode inductor is electrically connected with a first end of the second varistor, and a second output end of the second common mode inductor is electrically connected with a second end of the second varistor.

[0025] In one embodiment, the filter inductor unit further comprises a filter capacitor:

[0026] a first end of the filter capacitor is electrically connected with a first output end of the first common mode inductor and a first input end of the second common mode inductor respectively, and a second end of the filter capacitor is electrically connected with a second output end of the first common mode inductor and a second input end of the second common mode inductor respectively.

[0027] In one embodiment, the filter inductor unit further comprises a bleeder resistor;

[0028] a first end of the bleeder resistor is electrically connected with a first output end of the first common mode inductor and a first input end of the second common mode inductor respectively, and a second end of the bleeder resistor is electrically connected with a second output end of the first common mode inductor and a second input end of the second common mode inductor respectively.

[0029] In a second aspect, in one embodiment, the utility model provides a power supply system, including the lightning protection circuit of any one of above embodiment.

[0030] In a third aspect, in one embodiment, the utility model provides a power -using equipment, including the power supply system of any one of above embodiment.

[0031] In the lightning protection circuit, power supply system and power -using equipment, the residual voltage of the first voltage -dependent resistor is absorbed by setting the second voltage -dependent resistor after the first voltage -dependent resistor, thereby realizing the secondary absorption of the lightning voltage, so that when the input lightning voltage is too high, the voltage of the device or component flowing to the rear stage can be controlled in the safe range, thereby reducing the risk of damage of the device or component in the rear stage, and in addition, since the residual voltage of the first voltage -dependent resistor is smaller than the input lightning voltage, the starting threshold voltage of the second voltage -dependent resistor is relatively smaller than the first voltage -dependent resistor, so that the second voltage -dependent resistor can more reliably absorb the residual voltage of the first voltage -dependent resistor. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] Figure 1 The structure diagram of a lightning protection circuit provided by one embodiment of the present application is shown in the figure.

[0034] Figure 2 The structure diagram of a lightning protection circuit containing temperature fuse tube provided by one embodiment of the present application is shown in the figure.

[0035] Figure 3 The structure diagram of a lightning protection circuit containing voltage -dependent resistor for common mode lightning protection provided by one embodiment of the present application is shown in the figure.

[0036] Figure 4 The structure diagram of a lightning protection circuit containing filter inductance unit specific structure provided by one embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0038] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly limited as an example. In the present application, the word "exemplary" is used to mean "serving as an example, instance, or illustration". Any embodiment described as "exemplary" in the present application is not necessarily construed as preferred or advantageous over other embodiments. In order to enable any person skilled in the art 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 those skilled in the art can realize the present application without using these specific details. In other examples, well-known structures and processes will not be described in detail to avoid unnecessary details making 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 broadest scope consistent with the principles and characteristics disclosed.

[0039] In one embodiment, the present application provides a lightning protection circuit, comprising a first MOV 101, a second MOV 104 and a filter inductor unit U1. Figure 1

[0040] In the present application, the first MOV 101 comprises a first end electrically connected to the first input end of the filter inductor unit U1 and a second end electrically connected to the second input end of the filter inductor unit U1, and the second MOV 104 comprises a first end electrically connected to the first output end of the filter inductor unit U1 and a second end electrically connected to the second output end of the filter inductor unit U1. Figure 1

[0041] ​​The inductor in the filter inductor unit U1 is a passive component that primarily stores and releases electrical energy. The inductor is composed of one or more coils, and when the current through the inductor changes, a magnetic field is generated. This magnetic field stores electrical energy and releases it when the current changes, thereby achieving the effects of filtering and current stabilization.

[0042] Firstly, because the inductor has a high impedance to high-frequency signals, it can prevent high-frequency noise from entering the subsequent circuit through the inductor, thereby reducing noise interference in the power supply.

[0043] Secondly, the inductor can smooth the changes in current; when the power supply voltage changes, the inductor stores electrical energy and releases it when the voltage changes, thereby keeping the current relatively stable; this is very important for some devices that require stable current, such as electric motors and LED drivers.

[0044] In this embodiment, based on the characteristic that the voltage across the inductor cannot change abruptly, the voltage isolation effect is achieved, and most of the lightning strike voltage can be discharged through the first MOV 101 in the front stage.

[0045] Wherein, the inductor in the filter inductor unit U1, whether it is a differential mode inductor or a common mode inductor, has the voltage isolation effect involved in this embodiment.

[0046] Wherein, the starting threshold voltage of the second MOV 104 is less than that of the first MOV 101.

[0047] Wherein, the MOV is a special resistor device whose resistance value changes with voltage. The starting threshold voltage of the MOV is the lowest voltage at which the nonlinear resistance characteristic of the resistor device begins to appear. The nonlinear resistance characteristic of the MOV is determined by the internal semiconductor material and structure of the MOV. When the voltage is below the starting threshold voltage, the resistance of the MOV is very high, almost an open circuit state, with only a very small leakage current passing through. But when the voltage exceeds the starting threshold voltage, the resistance of the MOV will drop rapidly and become very low to protect the circuit from overvoltage damage.

[0048] Based on the above analysis, the input lightning voltage is released through the first MOV 101, and the residual voltage flowing to the second MOV 104 is relatively small. If the starting threshold voltage of the second MOV 104 is the same as or greater than that of the first MOV 101, it will be difficult or impossible for the second MOV 102 to release the input residual voltage, or the release effect will be poor, thereby causing the voltage flowing to the device or component in the subsequent stage to be relatively high, thereby reducing the lightning protection effect. Therefore, in view of this situation, the starting threshold voltage of the second MOV 104 is controlled to be less than that of the first MOV 101, so that the second MOV 104 can fully release the residual voltage flowing out of the first MOV 101.

[0049] Through the above lightning protection circuit, the second MOV is arranged in the subsequent stage of the first MOV, and the second MOV can absorb the residual voltage flowing out of the first MOV, thereby realizing secondary absorption of lightning voltage. When the input lightning voltage is too high, the voltage flowing to the device or component in the subsequent stage can be controlled within a safe range, thereby reducing the risk of damage to the device or component in the subsequent stage. In addition, since the residual voltage flowing out of the first MOV is relatively small relative to the input lightning voltage, the starting threshold voltage of the second MOV is relatively small relative to the first MOV, so that the second MOV can more reliably absorb the residual voltage flowing out of the first MOV.

[0050] As shown in Figure 2 , in one embodiment, the lightning protection circuit further comprises a temperature fuse tube FNTC101.

[0051] In Figure 2 , the temperature fuse tube FNTC101 comprises a first end electrically connected to the second end of the second MOV 104 and a second end electrically connected to the second output end of the filter inductor unit U1.

[0052] The temperature fuse tube FNTC101 is used to sense the temperature of the second MOV 104 and is disconnected when the temperature of the second MOV 104 exceeds a preset temperature.

[0053] In which, the temperature fuse tube FNTC101 is an electronic component for overheat protection. It is usually made of a metal wire or alloy wire wrapped in an insulating tube. The working principle of the temperature fuse tube FNTC101 is based on thermal expansion effect. When the temperature in the circuit exceeds the rated temperature of the temperature fuse tube FNTC101, the metal wire in the temperature fuse tube FNTC101 will break due to thermal expansion, thereby cutting off the circuit.

[0054] The temperature fuse tube FNTC 101 needs to be arranged close to the second pressure-sensitive resistor MOV 104 to sense the temperature thereof. Due to the arrangement position, there is a certain difference between the temperature sensed by the temperature fuse tube FNTC 101 and the actual temperature of the second pressure-sensitive resistor MOV 104. Therefore, when the temperature fuse tube FNTC 101 is determined, the rated temperature needs to be reasonable. Specifically, the preset temperature mentioned above is used to represent whether the temperature of the second pressure-sensitive resistor MOV 104 will cause a safety hazard. That is, when the temperature of the second pressure-sensitive resistor MOV 104 exceeds the preset temperature, the temperature sensed by the temperature fuse tube FNTC 101 also needs to exceed the rated temperature, so as to ensure that the circuit in which the second pressure-sensitive resistor MOV 104 is located can be disconnected.

[0055] For the above, it needs to be explained that according to the requirement of the third edition of the safety regulation UL26368, the pressure-sensitive resistor needs to be tested by inputting a multiple of the alternating voltage. For example, if the input alternating voltage is 240Vac, 480Vac input voltage is applied. At this time, if the pressure-sensitive resistor does not melt the shell due to heating, it is considered to meet the safety regulation requirement. In this scenario, the starting threshold voltage of the pressure-sensitive resistor needs to be at least 620Vdc or above to avoid this risk.

[0056] In the present application, the starting threshold voltage of the pressure-sensitive resistor needs to be as small as possible to ensure that the lightning voltage can be fully released.

[0057] In summary, in the scenario where the input alternating voltage is 240Vac, the starting threshold voltage of the first pressure-sensitive resistor MOV 101 cannot be lower than 620Vdc. In order to ensure the release of lightning voltage, the starting threshold voltage of the first pressure-sensitive resistor MOV 101 is set to 620Vdc. The second pressure-sensitive resistor MOV 104 arranged in the rear stage needs to fully release the residual voltage flowing out of the first pressure-sensitive resistor MOV 101. Therefore, the starting threshold voltage of the second pressure-sensitive resistor MOV 104 needs to be less than 620Vdc. According to the safety regulation requirement, the corresponding temperature fuse tube FNTC 101 needs to be arranged and connected in series with the second pressure-sensitive resistor MOV 104.

[0058] That is, the temperature fuse tube FNTC 101 is arranged in the present embodiment, which can not only make the starting threshold voltage of the second pressure-sensitive resistor MOV 104 smaller than that of the first pressure-sensitive resistor MOV 101 when the starting threshold voltage of the first pressure-sensitive resistor MOV 101 is the smallest, but also meet the safety regulation requirement.

[0059] In Figure 1 or Figure 2 In one embodiment, the release current of the second pressure-sensitive resistor MOV 104 is less than that of the first pressure-sensitive resistor MOV 101.

[0060] The release current represents the energy release capability.

[0061] The release current is positively correlated with the energy release capability. The greater the release current, the stronger the corresponding energy release capability. In an ideal case, the greater the energy release capability of the pressure-sensitive resistor, the higher the cost. In the embodiment, the second pressure-sensitive resistor MOV104 is used to release the residual voltage of the first pressure-sensitive resistor MOV101. The corresponding energy is relatively small relative to the lightning voltage (release object of the first pressure-sensitive resistor MOV101), so the second pressure-sensitive resistor MOV104 does not need to have a release current greater than or equal to that of the first pressure-sensitive resistor MOV101.

[0062] In summary, the starting threshold voltage and the release current of the second pressure-sensitive resistor MOV104 are both smaller than those of the first pressure-sensitive resistor MOV101. For example, the first pressure-sensitive resistor MOV101 uses a pressure-sensitive resistor of model 10D621, whose starting threshold voltage is 620Vdc, and the energy release capability corresponds to a release current of 3500A. The second pressure-sensitive resistor MOV104 uses a pressure-sensitive resistor of model 10D561, whose starting threshold voltage is 560Vdc, and the energy release capability corresponds to a release current of 2000A. Of course, without considering the cost, the release current corresponding to the energy release capability of the second pressure-sensitive resistor MOV104 can also be 3500A, but a smaller specification is generally used under the pressure of cost.

[0063] As shown in FIG. 1, in one embodiment, the lightning protection circuit further includes a third pressure-sensitive resistor MOV102 and a fourth pressure-sensitive resistor MOV103. Figure 3

[0064] The third pressure-sensitive resistor MOV102 includes a first end electrically connected to the first end of the first pressure-sensitive resistor MOV101 and the first input end of the filter inductor unit U1, and a second end grounded through a current-limiting resistor FDG101. Figure 3

[0065] The fourth pressure-sensitive resistor MOV103 includes a first end electrically connected to the second end of the first pressure-sensitive resistor MOV101 and the second input end of the filter inductor unit U1, and a second end grounded through a current-limiting resistor FDG101. Figure 3

[0066] The first pressure-sensitive resistor MOV101 and the second pressure-sensitive resistor MOV104 are used to absorb and release the differential mode lightning voltage, and the third pressure-sensitive resistor MOV102 and the fourth pressure-sensitive resistor MOV103 are used to absorb and release the common mode lightning voltage.

[0067] ​​​Among them, the third varistor MOV102 and the fourth varistor MOV103 can both be varistors of model 14D621.

[0068] like Figure 4 As shown, in one embodiment, the filter inductor unit U1 includes a first common-mode inductor LF101 and a second common-mode inductor LF102.

[0069] Among them, Figure 4 In the first common-mode inductor LF101, there are a first input terminal electrically connected to the first terminal of the first varistor MOV101, a second input terminal electrically connected to the second terminal of the first varistor MOV101, a first output terminal electrically connected to the first input terminal of the second common-mode inductor LF102, and a second output terminal electrically connected to the second input terminal of the second common-mode inductor LF102.

[0070] Among them, Figure 4 In the second common-mode inductor LF102, there are also a first output terminal electrically connected to the first terminal of the second varistor MOV104 and a second output terminal electrically connected to the second terminal of the second varistor MOV104.

[0071] The filter structure based on two common-mode inductors can better isolate the voltage effect, thereby enabling the first varistor MOV101 to more fully absorb and release the lightning voltage.

[0072] like Figure 4 As shown, in one embodiment, the filter inductor unit U1 further includes a filter capacitor CX1.

[0073] Among them, Figure 4 In the filter capacitor CX1, there is a first end that is electrically connected to the first output terminal of the first common-mode inductor LF101 and the first input terminal of the second common-mode inductor LF102, and a second end that is electrically connected to the second output terminal of the first common-mode inductor LF101 and the second input terminal of the second common-mode inductor LF102.

[0074] Among them, the filter capacitor CX1 is used to achieve filtering. Its specific function and principle can be referred to the relevant existing technology, and will not be elaborated here.

[0075] like Figure 4 As shown, in one embodiment, the filter inductor unit U1 further includes bleed resistors R1, R2, R3, and R4.

[0076] Among them, Figure 4In the above, the bleeder resistors R3 and R4 each include a first terminal electrically connected to the first output terminal of the first common-mode inductor LF101 and the first input terminal of the second common-mode inductor LF102, and a second terminal electrically connected to the first terminal of the bleeder resistor R1 and the first terminal of the bleeder resistor R2, respectively.

[0077] Among them, Figure 4 In the process, the bleeder resistors R1 and R2 also include a first terminal that is electrically connected to the second terminal of the bleeder resistor R3 and the second terminal of the bleeder resistor R4, respectively, and a second terminal that is electrically connected to the second output terminal of the first common-mode inductor LF101 and the second input terminal of the second common-mode inductor LF102, respectively.

[0078] Among them, the bleed resistors R1, R2, R3 and R4 are all used to provide a bleed circuit so that the energy on the filter capacitor CX1, the first common mode inductor LF101 and the second common mode inductor LF102 can be discharged.

[0079] In one embodiment, the surge protection circuit further includes a first fuse and a second fuse.

[0080] The first fuse is used to provide overcurrent protection for the current entering from the input terminal and flowing to the first varistor, and the second fuse is used to provide overcurrent protection for the current entering from the first varistor and flowing to the first common-mode inductor.

[0081] like ​ As shown, the lightning strike voltage is applied to the first varistor MOV101 through the power input terminal (specifically, the L line or N line in single-phase AC; and the A line, B line, C line, or N line in three-phase AC). Because the lightning strike voltage amplitude is very high, exceeding the start-up threshold voltage of the first varistor MOV101, it does not completely discharge the lightning strike voltage, thus forming a primary residual voltage. This primary residual voltage is applied to the second varistor MOV104 through the first common-mode inductor LF101, the second common-mode inductor LF102, and the thermal fuse FNTC101. After being discharged by the second varistor MOV104, the primary residual voltage is further reduced. Although the second varistor MOV104 also forms a secondary residual voltage, its amplitude is very low and will not damage downstream devices or components, thus providing lightning protection for the power supply.

[0082] Secondly, in one embodiment, the present invention provides a power supply system including the surge protection circuit in any of the above embodiments.

[0083] In the power supply system, in addition to the lightning protection circuit, a rectifier bridge, a high-voltage electrolytic capacitor, a high-voltage MOS tube, a power supply PWM control chip and the like are electrically connected in the rear stage of the lightning protection circuit.

[0084] Through the power supply system, the second varistor is arranged in the rear stage of the first varistor, and the second varistor can absorb the residual voltage flowing out of the first varistor, thereby realizing secondary absorption of the lightning strike voltage, and when the input lightning strike voltage is too high, the voltage flowing to the device or component in the rear stage can be controlled in a safe range, thereby reducing the risk of damage of the device or component in the rear stage.

[0085] In a third aspect, in one embodiment, the utility model provides a kind of electric equipment, including the power supply system in any one of the above embodiments.

[0086] In the electric equipment, in addition to the power supply system, an electric load such as a motor, a display and the like is electrically connected in the rear stage of the power supply system.

[0087] Through the electric equipment, the second varistor is arranged in the rear stage of the first varistor, and the second varistor can absorb the residual voltage flowing out of the first varistor, thereby realizing secondary absorption of the lightning strike voltage, and when the input lightning strike voltage is too high, the voltage flowing to the device or component in the rear stage can be controlled in a safe range, thereby reducing the risk of damage of the device or component in the rear stage.

[0088] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the detailed description of other embodiments above, which will not be repeated here.

[0089] The lightning protection circuit, the power supply system and the electric equipment provided by the present application are described in detail above, and the principles and implementation modes of the present application are described by applying specific examples; the above embodiment descriptions are only used to help understand the method and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range can be changed, and the above description should not be understood as limiting the present application.

[0090] The technical features of the above embodiments can be combined in any manner. For the sake of brevity, not all possible combinations of the technical features described above are described, however, it is to be understood that any combination of the technical features is within the scope of the present specification, provided that the combination is not clearly contradictory or impossible.

Claims

1. A lightning protection circuit, characterized in that, The lightning protection circuit comprises: a first voltage-dependent resistor, a second voltage-dependent resistor, and a filter inductor unit; the first voltage-dependent resistor comprises a first end electrically connected to a first input end of the filter inductor unit and a second end electrically connected to a second input end of the filter inductor unit; and the second voltage-dependent resistor comprises a first end electrically connected to a first output end of the filter inductor unit and a second end electrically connected to a second output end of the filter inductor unit; wherein a starting threshold voltage of the second voltage-dependent resistor is less than that of the first voltage-dependent resistor; the lightning protection circuit further comprises: a temperature fuse tube; the temperature fuse tube comprises a first end electrically connected to the second end of the second voltage-dependent resistor and a second end electrically connected to the second output end of the filter inductor unit; the temperature fuse tube is used to sense the temperature of the second voltage-dependent resistor and is disconnected when the temperature of the second voltage-dependent resistor exceeds a preset temperature; a release current of the second voltage-dependent resistor is less than that of the first voltage-dependent resistor; wherein the release current represents an energy release capability.

2. The lightning protection circuit of claim 1, wherein, The lightning protection circuit further comprises: a third voltage-dependent resistor and a fourth voltage-dependent resistor; a first end of the third voltage-dependent resistor is electrically connected to the first end of the first voltage-dependent resistor and the first input end of the filter inductor unit respectively, and a second end of the third voltage-dependent resistor is grounded; a first end of the fourth voltage-dependent resistor is electrically connected to the second end of the first voltage-dependent resistor and the second input end of the filter inductor unit respectively, and a second end of the fourth voltage-dependent resistor is grounded.

3. The lightning protection circuit of claim 2, wherein, The lightning protection circuit further comprises: a current-limiting resistor; a first end of the current-limiting resistor is electrically connected to the second end of the third voltage-dependent resistor and the second end of the fourth voltage-dependent resistor respectively, and a second end of the current-limiting resistor is grounded.

4. The lightning protection circuit of claim 1, wherein, The filter inductor unit comprises a first common-mode inductor and a second common-mode inductor; a first input end of the first common-mode inductor is electrically connected to the first end of the first voltage-dependent resistor, a second input end of the first common-mode inductor is electrically connected to the second end of the first voltage-dependent resistor, a first output end of the first common-mode inductor is electrically connected to a first input end of the second common-mode inductor, and a second output end of the first common-mode inductor is electrically connected to a second input end of the second common-mode inductor; a first output end of the second common-mode inductor is electrically connected to the first end of the second voltage-dependent resistor, and a second output end of the second common-mode inductor is electrically connected to the second end of the second voltage-dependent resistor.

5. The lightning protection circuit of claim 4, wherein, The filter inductor unit further comprises a filter capacitor; a first end of the filter capacitor is electrically connected to the first output end of the first common-mode inductor and the first input end of the second common-mode inductor respectively, and a second end of the filter capacitor is electrically connected to the second output end of the first common-mode inductor and the second input end of the second common-mode inductor respectively.

6. The lightning protection circuit of claim 4, wherein, The filter inductor unit further comprises a bleeder resistor; a first end of the bleeder resistor is electrically connected to the first output end of the first common-mode inductor and the first input end of the second common-mode inductor respectively, and a second end of the bleeder resistor is electrically connected to the second output end of the first common-mode inductor and the second input end of the second common-mode inductor respectively.

7. A power supply system characterized by comprising: The lightning protection circuit comprises any one of claims 1 to 5.

8. An electric device, characterized by The power supply system according to claim 7. The power supply system according to claim 7.

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