Dual protection type lightning protection circuit

Abstract

The utility model discloses a dual-protection type lightning protection circuit. The dual-protection type lightning protection circuit comprises a differential-mode discharge unit, a first common-mode discharge unit and a second common-mode discharge unit, the differential mode discharge unit comprises a first surge protection module and a first low-pass filtering module; the first common-mode discharge unit comprises a second surge protection module and a second low-pass filtering module; the second common-mode discharge unit comprises a third surge protection module and a third low-pass filtering module. According to the dual-protection type lightning protection circuit provided by the utility model, the first surge protection module, the first low-pass filtering module, the second surge protection module, the second low-pass filtering module, the third surge protection module and the third low-pass filtering module are arranged, so that differential-mode and common-mode lightning surge can be effectively discharged; and meanwhile, before the surge protection module is started, high-frequency surge can be filtered out through the low-pass filtering module, so that double protection is carried out on equipment, and the electronic equipment is effectively prevented from being damaged by lightning surge.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to a double-protection lightning protection circuit. Background Art

[0002] Lightning disasters are listed as one of the ten most serious natural disasters by the United Nations. Every year, lightning poses a serious threat to people's personal and property safety. Since induced lightning spreads in all directions, it is easy to invade equipment along the power line or ground line. Electronic equipment is particularly vulnerable to damage. How to effectively protect electronic equipment from lightning strikes has become an important issue.

[0003] The existing technology generally increases the grounding grid to minimize the grounding resistance and discharge the lightning current. The actual result is that a lot of manpower and financial resources are spent, the lightning protection effect is not satisfactory, and there are endless cases of equipment being damaged by lightning. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides a practical double protection lightning protection circuit technology, which aims to improve the shortcomings of relying on ground grid lightning protection. The specific technical solution is:

[0005] A double protection lightning protection circuit is used to be connected between a power supply and a device, wherein the power supply includes a phase line terminal, a neutral line terminal and a ground line terminal, and the double protection lightning protection circuit includes:

[0006] A differential mode discharge unit, comprising a first surge protection module and a first low-pass filter module, wherein one end of the first surge protection module is connected to the phase line end, and the other end is connected to the neutral line end, and the first low-pass filter module is connected to the first surge protection module;

[0007] A first common-mode discharge unit includes a second surge protection module and a second low-pass filter module, one end of the second surge protection module is connected to the phase line terminal, and the other end is connected to the ground line terminal, and the second low-pass filter module is connected to the second surge protection module;

[0008] A second common-mode discharge unit includes a third surge protection module and a third low-pass filter module, one end of the third surge protection module is connected to the neutral line end, and the other end is connected to the ground line end, and the third low-pass filter module is connected to the third surge protection module;

[0009] The first low-pass filtering module, the second low-pass filtering module and the third low-pass filtering module are used to filter out signal components with a frequency higher than 50 Hz.

[0010] Preferably,

[0011] The first low-pass filter module includes at least one inductor element and two capacitor elements, one end of the inductor element is connected to the phase line end to form a first input end, and the other end is connected to the device to form a first output end, and the two capacitor elements are connected to the first input end and the first output end respectively;

[0012] The second low-pass filter module includes at least one inductor and two capacitors, one end of the inductor is connected to the phase line end to form a second input end, and the other end is connected to the device to form a second output end, and the two capacitors are connected to the second input end and the second output end respectively;

[0013] The third low-pass filter module includes at least one inductor element and two capacitor elements, one end of the inductor element is connected to the neutral line end to form a third input end, and the other end is connected to the device to form a third output end, and the two capacitor elements are respectively connected to the third input end and the third output end.

[0014] Preferably, the first low-pass filtering module and the second low-pass filtering module share at least one inductor element.

[0015] Preferably,

[0016] The first low-pass filter module includes a first inductor, a first input-side capacitor and a first output-side capacitor, wherein a first end of the first input-side capacitor is connected to a first end of the first inductor, a second end of the first input-side capacitor is connected to the neutral line, a first end of the first output-side capacitor is connected to a second end of the first inductor, and a second end of the first output-side capacitor is connected to the neutral line;

[0017] The second low-pass filter module includes the first inductor, a second input-side capacitor and a second output-side capacitor, wherein a first end of the second input-side capacitor is connected to a first end of the first inductor, a second end of the second input-side capacitor is connected to the ground terminal, a first end of the second output-side capacitor is connected to a second end of the first inductor, and a second end of the second output-side capacitor is connected to the neutral terminal;

[0018] The third low-pass filtering module includes a third inductor element, a third input side capacitor element and a third output side capacitor element, the first end of the third input side capacitor element is connected to the first end of the third inductor element, the second end of the third input side capacitor element is connected to the ground terminal, the first end of the third output side capacitor element is connected to the second end of the third inductor element, and the second end of the third output side capacitor element is connected to the ground terminal.

[0019] Preferably,

[0020] The first surge protection module comprises a first input-side surge protector and a first output-side surge protector, wherein a first end of the first input-side surge protector is connected to a first end of the first inductor element, a second end of the first input-side surge protector is connected to the neutral line end, a first end of the first output-side surge protector is connected to a second end of the first inductor element, and a second end of the first output-side surge protector is connected to the neutral line end;

[0021] The second surge protection module comprises a second input-side surge protector and a second output-side surge protector, wherein a first end of the second input-side surge protector is connected to a first end of the first inductor element, a second end of the second input-side surge protector is connected to the ground terminal, a first end of the second output-side surge protector is connected to a second end of the first inductor element, and a second end of the second output-side surge protector is connected to the ground terminal;

[0022] The third surge protection module includes a third input-side surge protector and a third output-side surge protector, wherein the first end of the third input-side surge protector is connected to the first end of the third inductor element, the second end of the third input-side surge protector is connected to the ground terminal, the first end of the third output-side surge protector is connected to the second end of the third inductor element, and the second end of the third output-side surge protector is connected to the ground terminal.

[0023] Preferably,

[0024] The maximum continuous operating voltage of the first input-side surge protector is greater than the maximum continuous operating voltage of the first output-side surge protector;

[0025] The maximum continuous operating voltage of the second input-side surge protector is greater than the maximum continuous operating voltage of the second output-side surge protector;

[0026] The maximum continuous operating voltage of the third input-side surge protector is greater than the maximum continuous operating voltage of the third output-side surge protector.

[0027] Preferably,

[0028] The second ends of the first input-side capacitive element and the first input-side surge protector are connected to the first end of the third inductive element;

[0029] The second ends of the first output-side capacitive element and the first output-side surge protector are connected to the second end of the third inductive element.

[0030] Preferably,

[0031] The ground terminal includes an input side ground terminal and an output side ground terminal;

[0032] The second input side capacitor element, the second input side surge protector, the third input side capacitor element and the second end of the third input side surge protector are connected to the input side ground terminal;

[0033] The second output-side capacitive element, the second output-side surge protector, the third output-side capacitive element, and the second end of the third output-side surge protector are connected to the output-side ground terminal.

[0034] Preferably, an inductive device is connected between the ground terminal and the first common-mode discharge unit and the second common-mode discharge unit.

[0035] The utility model provides a double protection lightning protection circuit, which effectively discharges differential mode and common mode lightning surges by arranging a first surge protection module and a first low-pass filter module between the phase line terminal and the neutral line terminal, arranging a second surge protection module and a second low-pass filter module between the phase line terminal and the ground line terminal, and arranging a third surge protection module and a third low-pass filter module between the neutral line terminal and the ground line terminal. At the same time, before the surge protection module is started, the high-frequency surge can be filtered out by the low-pass filter module, thereby performing double protection on the equipment and effectively avoiding damage to the electronic equipment by lightning surges. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A schematic block diagram of a double protection lightning protection circuit provided by an embodiment of the utility model;

[0038] Figure 2 A circuit diagram of a double protection lightning protection circuit provided in an embodiment of the utility model.

[0039] Reference numerals

[0040] 100-phase line terminal; 200-neutral line terminal; 300-ground line terminal; 310-input side ground line terminal; 320-output side ground line terminal;

[0041] 1-differential mode discharge unit; 11-first surge protection module; 111-first input side surge protector; 112-first output side surge protector; 12-first low-pass filter module; 121-first inductor element; 122-first input side capacitor element; 123-first output side capacitor element;

[0042] 2-first common mode discharge unit; 21-second surge protection module; 211-second input side surge protector; 212-second output side surge protector; 22-second low-pass filter module; 222-second input side capacitor element; 223-second output side capacitor element;

[0043] 3-second common-mode discharge unit; 31-third surge protection module; 311-third input side surge protector; 312-third output side surge protector; 32-third low-pass filter module; 321-third inductor element; 322-third input side capacitor element; 323-third output side capacitor element. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the technical solution of the utility model, the utility model is described in detail below in conjunction with the accompanying drawings. The description in this part is only exemplary and explanatory and should not have any limiting effect on the protection scope of the utility model.

[0045] It should be noted that similar reference numerals denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition and explanation in the subsequent drawings.

[0046] It should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", etc. are only used to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0047] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0048] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] See also Figure 1 and Figure 2 This embodiment provides a double protection lightning protection circuit, which is used to be connected between a power supply and a device. The power supply includes a phase line terminal 100, a neutral line terminal 200 and a ground line terminal 300. The double protection lightning protection circuit includes a differential mode discharge unit 1, a first common mode discharge unit 2 and a second common mode discharge unit 3.

[0050] The differential mode discharge unit 1 includes a first surge protection module 11 and a first low-pass filter module 12 . One end of the first surge protection module 11 is connected to the phase line terminal 100 , and the other end is connected to the neutral line terminal 200 . The first low-pass filter module 12 is connected to the first surge protection module 11 .

[0051] The first common-mode discharge unit 2 includes a second surge protection module 21 and a second low-pass filter module 22 . One end of the second surge protection module 21 is connected to the phase line terminal 100 , and the other end is connected to the ground line terminal 300 . The second low-pass filter module 22 is connected to the second surge protection module 21 .

[0052] The second common mode discharge unit 3 includes a third surge protection module 31 and a third low pass filter module 32 . One end of the third surge protection module 31 is connected to the neutral line terminal 200 , and the other end is connected to the ground line terminal 300 . The third low pass filter module 32 is connected to the third surge protection module 31 .

[0053] The first low-pass filtering module 12 , the second low-pass filtering module 22 and the third low-pass filtering module 32 are used to filter out signal components with a frequency higher than 50 Hz.

[0054] Among them, the phase line terminal 100 is the live line terminal, and the neutral line terminal 200 is the neutral line terminal. Lightning surges can be divided into differential mode and common mode. Differential mode refers to the way in which a signal is transmitted or processed through two opposite conductors in a circuit. The differential mode signal consists of a forward signal and a reverse signal, which are transmitted on the wire with equal but opposite amplitudes; the common mode refers to the way in which a signal is transmitted or processed in the same way through two conductors in a circuit. The common mode signal is the signal on the two conductors changing at the same time with the same amplitude. Specifically, the differential mode lightning surge will flow into the device through the phase line terminal 100 and then flow back to the neutral line terminal 200, and the common mode lightning surge will flow into the device through the phase line terminal 100 and the neutral line terminal 200 respectively. Therefore, when performing lightning protection, it is necessary to protect the differential mode and common mode lightning surges at the same time.

[0055] For differential mode lightning surges, the first surge protection module 11 can discharge high-energy surges, and before the surge voltage reaches the starting voltage of the first surge protection module 11, and during the period from reaching the starting voltage to requiring starting time, the high-frequency surge is filtered out by the first low-pass filter module 12.

[0056] For common-mode lightning surges, the second surge protection module 21 can discharge high-energy surges on the phase line terminal 100, and the third surge protection module 31 can discharge surges on the neutral line terminal 200. Similarly, before the surge voltage reaches the starting voltage of the second surge protection module 21 and the third surge protection module 31, and during the period from reaching the starting voltage to requiring starting time, the high-frequency surge is filtered out by the second low-pass filter module 22 and the third low-pass filter module 32.

[0057] The present embodiment provides a double protection lightning protection circuit, which effectively discharges differential mode and common mode lightning surges by arranging a first surge protection module and a first low-pass filter module between the phase line terminal and the neutral line terminal, a second surge protection module and a second low-pass filter module between the phase line terminal and the ground line terminal, and a third surge protection module and a third low-pass filter module between the neutral line terminal and the ground line terminal. At the same time, before the surge protection module is started, the high-frequency surge can be filtered out by the low-pass filter module, thereby providing double protection for the equipment and effectively avoiding damage to the electronic equipment by lightning surges.

[0058] Furthermore, in the examples provided in this embodiment:

[0059] The first low-pass filter module 12 includes at least one inductor and two capacitors. One end of the inductor is connected to the phase line terminal 100 to form a first input end, and the other end is connected to the device to form a first output end. The two capacitors are connected to the first input end and the first output end respectively.

[0060] The second low-pass filter module 22 includes at least one inductor and two capacitors. One end of the inductor is connected to the phase line terminal 100 to form a second input terminal, and the other end is connected to the device to form a second output terminal. The two capacitors are connected to the second input terminal and the second output terminal respectively.

[0061] The third low-pass filter module 32 includes at least one inductor and two capacitors. One end of the inductor is connected to the neutral line terminal 200 to form a third input terminal, and the other end is connected to the device to form a third output terminal. The two capacitors are connected to the third input terminal and the third output terminal respectively.

[0062] Among them, the inductor element and the two capacitor elements are arranged to form a π-type low-pass filter, which can generate high impedance at high frequencies and low impedance at low frequencies, thereby reducing the high-frequency components in the signal, narrowing the output signal relative to the input signal frequency range, and effectively controlling the cut-off frequency. The π-type filter is a common technical means in this field, so this embodiment is not described in detail. The size of the cut-off frequency can be accurately controlled by reasonably selecting the value of the capacitor or inductor. In this embodiment, the π-type low-pass filter, that is, the cut-off frequency of the first low-pass filter module 12, the second low-pass filter module 22 and the third low-pass filter module 32 is 50Hz, so that the mains power of 50Hz frequency can pass through with negligible influence, and the high-frequency surge is filtered out.

[0063] Furthermore, the first low-pass filtering module 12 and the second low-pass filtering module 22 share at least one inductor element.

[0064] Among them, the first low-pass filter module 12 and the second low-pass filter module 22 can both filter out high-frequency surges at the phase line terminal 100, and both are composed of inductors and capacitors, so the two can share an inductor, and connect their capacitors to the neutral line terminal 200 and the ground line terminal 300 respectively to filter out high-frequency surges in differential mode and common mode.

[0065] For further information, see Figure 2 , in the examples provided in this implementation:

[0066] The first low-pass filter module 12 includes a first inductor element 121, a first input side capacitor element 122 and a first output side capacitor element 123, wherein the first end of the first input side capacitor element 122 is connected to the first end of the first inductor element 121, the second end of the first input side capacitor element 122 is connected to the neutral line terminal 200, the first end of the first output side capacitor element 123 is connected to the second end of the first inductor element 121, and the second end of the first output side capacitor element 123 is connected to the neutral line terminal 200.

[0067] The second low-pass filter module 22 includes a first inductor element 121, a second input side capacitor element 222 and a second output side capacitor element 223, wherein the first end of the second input side capacitor element 222 is connected to the first end of the first inductor element 121, the second end of the second input side capacitor element 222 is connected to the ground terminal 300, the first end of the second output side capacitor element 223 is connected to the second end of the first inductor element 121, and the second end of the second output side capacitor element 223 is connected to the neutral line terminal 200.

[0068] The third low-pass filter module 32 includes a third inductor element 321, a third input side capacitor element 322 and a third output side capacitor element 323, wherein the first end of the third input side capacitor element 322 is connected to the first end of the third inductor element 321, the second end of the third input side capacitor element 322 is connected to the ground terminal 300, the first end of the third output side capacitor element 323 is connected to the second end of the third inductor element 321, and the second end of the third output side capacitor element 323 is connected to the ground terminal 300.

[0069] The first input terminal and the second input terminal are the first terminal of the first inductor element 121 , the first output terminal and the second output terminal are the second terminal of the first inductor element 121 ; the third input terminal is the first terminal of the third inductor element 321 , and the third output terminal is the second terminal of the third inductor element 321 .

[0070] Specifically, the first inductor element 121, the first input side capacitor element 122 and the first output side capacitor element 123 together constitute a π-type low-pass filter, which is arranged between the phase line terminal 100 and the neutral line terminal 200, and can effectively filter out high-frequency surges in the differential mode; the first inductor element 121, the second input side capacitor element 222 and the second output side capacitor element 223 together constitute a π-type filter, which is arranged between the phase line terminal 100 and the ground line terminal 300, and can effectively filter out high-frequency surges flowing through the phase line terminal 100 in the common-share mode; the third inductor element 321, the third input side capacitor element 322 and the third output side capacitor element 323 together constitute a π-type filter, which is arranged between the neutral line terminal 200 and the ground line terminal 300, and can effectively filter out high-frequency surges flowing through the neutral line 200 in the common-share mode.

[0071] For further information, see Figure 2 , in the examples provided in this implementation:

[0072] The first surge protection module 11 includes a first input-side surge protector 111 and a first output-side surge protector 112, wherein the first end of the first input-side surge protector 111 is connected to the first end of the first inductor element 121, the second end of the first input-side surge protector 111 is connected to the neutral line terminal 200, the first end of the first output-side surge protector 112 is connected to the second end of the first inductor element 121, and the second end of the first output-side surge protector 112 is connected to the neutral line terminal 200.

[0073] The second surge protection module 21 includes a second input-side surge protector 211 and a second output-side surge protector 212, wherein the first end of the second input-side surge protector 211 is connected to the first end of the first inductor element 121, the second end of the second input-side surge protector 211 is connected to the ground terminal 300, the first end of the second output-side surge protector 212 is connected to the second end of the first inductor element 121, and the second end of the second output-side surge protector 212 is connected to the ground terminal 300.

[0074] The third surge protection module 31 includes a third input side surge protector 311 and a third output side surge protector 312, wherein the first end of the third input side surge protector 311 is connected to the first end of the third inductor element 321, the second end of the third input side surge protector 311 is connected to the ground terminal 300, the first end of the third output side surge protector 312 is connected to the second end of the third inductor element 321, and the second end of the third output side surge protector 312 is connected to the ground terminal 300.

[0075] Among them, the wiring method of the first input side surge protector 111 and the first output side surge protector 112 is a discharge gap type, that is, a surge protector is set between the phase line and the neutral line, and a surge protector is set between the neutral line and the ground line. In a high-current grounding system, and in the case of high-voltage and low-voltage common grounding, if a high-side fault may cause a high potential on the low-voltage side, if the distribution system surge protector does not adopt this wiring method, it will cause devastating damage and electrical failure in this fault state. Therefore, this wiring method is mostly used in surge protectors in high-current grounding systems.

[0076] Specifically, the first input side surge protector 111 is arranged before the first inductor element 121, and the first output side surge protector 112 is arranged after the first inductor element 121, and the first input side surge protector 111 and the first output side surge protector 112 are both connected to the phase line terminal 100 and the neutral line terminal 200 to discharge the lightning surge in the differential mode. The lightning surge is discharged by the surge protectors on both sides of the first inductor element 121, which can more effectively protect the equipment; the second input side surge protector 211 is arranged before the first inductor element 121, and the second output side surge protector 212 is arranged after the first inductor element 121, and the second input side surge protector 211 and the second output side surge protector 212 Both are connected to the phase line terminal 100 and the ground line terminal 300 to discharge the lightning surge of the phase line terminal 100 in the common-sharing mode, and the lightning surge is discharged by the surge protectors on both sides of the first inductor element 121, which can more effectively protect the equipment; the third input side surge protector 311 is arranged before the third inductor element 321, and the third output side surge protector 312 is arranged after the third inductor element 321, and the third input side surge protector 311 and the third output side surge protector 312 are both connected to the neutral line terminal 200 and the ground line terminal 300 to discharge the lightning surge of the neutral line terminal 200 in the common-sharing mode. The lightning surge is discharged by the surge protectors on both sides of the third inductor element 321, which can more effectively protect the equipment.

[0077] Furthermore, in the examples provided in this embodiment:

[0078] The maximum continuous operating voltage of the first input-side surge protector 111 is greater than the maximum continuous operating voltage of the first output-side surge protector 112 .

[0079] The maximum continuous operating voltage of the second input-side surge protector 211 is greater than the maximum continuous operating voltage of the second output-side surge protector 212 .

[0080] The maximum continuous operating voltage of the third input-side surge protector 311 is greater than the maximum continuous operating voltage of the third output-side surge protector 312 .

[0081] Among them, the maximum continuous working voltage of the surge protector is the starting voltage of the surge protector. Specifically, two surge protectors are provided at the front and rear ends of the first inductor element 121 and the third inductor element 321. The specification of the surge protector at the rear end is smaller than that of the surge protector at the front end to effectively discharge the residual surge.

[0082] Furthermore, in the examples provided in this embodiment:

[0083] The first input side capacitor 122 and the second end of the first input side surge protector 111 are connected to the first end of the third inductor 321; the first output side capacitor 123 and the second end of the first output side surge protector 112 are connected to the second end of the third inductor 321. The first inductor 121 and the third inductor 321 are located between the first input side surge protector 111 and the first output side surge protector 112, so that the first output side surge protector 112 can more easily discharge the residual lightning surge.

[0084] Furthermore, in the examples provided in this embodiment:

[0085] The ground terminal 300 includes an input-side ground terminal 310 and an output-side ground terminal 320 .

[0086] Second ends of the second input-side capacitive element 222 , the second input-side surge protector 211 , the third input-side capacitive element 322 , and the third input-side surge protector 311 are connected to the input-side ground terminal 310 .

[0087] The second output-side capacitive element 223 , the second output-side surge protector 212 , the third output-side capacitive element 323 , and the second end of the third output-side surge protector 312 are connected to the output-side ground terminal 320 .

[0088] Furthermore, an inductive device is connected between the ground terminal 300 and the first common-mode discharge unit 2 and the second common-mode discharge unit 3 .

[0089] Specifically, the inductive device may be an inductor. When a surge invades the ground line, the inductor's characteristic of passing direct current and blocking alternating current can effectively prevent high-frequency surges from entering the device.

[0090] Working principle:

[0091] For the lightning surge in differential mode, the first inductor element 121, the first input side capacitor element 122 and the first output side capacitor element 123 form a π-type low-pass filter, and the cut-off frequency is designed to be greater than 50Hz, so that the AC power can pass through with negligible influence, and the surge is filtered out. Before the first input side surge protector 111 and the second input side surge protector 112 reach the starting voltage, or during the period when the starting voltage is reached but the starting time is still required, the high-frequency surge is filtered out by the π-type low-pass filter. When the surge protector is started, the discharge of the high-energy surge is completed by the surge protector, and the voltage is clamped within the set range;

[0092] For the lightning surge in the common-mode, the first inductor element 121, the second input-side capacitor element 222 and the second output-side capacitor element 223 form a π-type low-pass filter for filtering the lightning surge on the phase line terminal 100, and the third inductor element 321, the third input-side capacitor element 322 and the third output-side capacitor element 323 form a π-type low-pass filter for filtering the lightning surge on the neutral line terminal 200. The filtering principle is the same as above.

[0093] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes 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 apparatus.

[0094] This article uses specific examples to illustrate the principles and implementation methods of the utility model. The description of the above embodiments is only used to help understand the method and core ideas of the utility model. The above are only preferred implementation methods of the utility model. It should be pointed out that due to the limitations of textual expression, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principle of the utility model, they can also make several improvements, embellishments or changes, and can also combine the above technical features in an appropriate manner; these improvements, embellishments, changes or combinations, or the direct application of the concept and technical solution of the utility model to other occasions without improvement, should be regarded as the protection scope of the utility model.

Claims

1. A double protection lightning protection circuit, used to connect between a power supply and a device, characterized in that: The power supply comprises a phase line terminal (100), a neutral line terminal (200) and a ground line terminal (300), and the double protection lightning protection circuit comprises: A differential mode discharge unit (1) comprises a first surge protection module (11) and a first low-pass filter module (12), wherein one end of the first surge protection module (11) is connected to the phase line end (100), and the other end is connected to the neutral line end (200), and the first low-pass filter module (12) is connected to the first surge protection module (11); A first common-mode discharge unit (2), comprising a second surge protection module (21) and a second low-pass filter module (22), wherein one end of the second surge protection module (21) is connected to the phase line terminal (100), and the other end is connected to the ground line terminal (300), and the second low-pass filter module (22) is connected to the second surge protection module (21); A second common-mode discharge unit (3), comprising a third surge protection module (31) and a third low-pass filter module (32), wherein one end of the third surge protection module (31) is connected to the neutral line terminal (200), and the other end is connected to the ground line terminal (300), and the third low-pass filter module (32) is connected to the third surge protection module (31); The first low-pass filtering module (12), the second low-pass filtering module (22) and the third low-pass filtering module (32) are used to filter out signal components with a frequency higher than 50 Hz.

2. The double protection lightning protection circuit according to claim 1 is characterized in that: The first low-pass filter module (12) comprises at least one inductor element and two capacitor elements, one end of the inductor element is connected to the phase line end (100) to form a first input end, and the other end is connected to the device to form a first output end, and the two capacitor elements are respectively connected to the first input end and the first output end; The second low-pass filter module (22) comprises at least one inductor element and two capacitor elements, one end of the inductor element is connected to the phase line end (100) to form a second input end, and the other end is connected to the device to form a second output end, and the two capacitor elements are connected to the second input end and the second output end respectively; The third low-pass filter module (32) comprises at least one inductor element and two capacitor elements, one end of the inductor element is connected to the neutral line end (200) to form a third input end, and the other end is connected to the device to form a third output end, and the two capacitor elements are respectively connected to the third input end and the third output end.

3. The double protection lightning protection circuit according to claim 2 is characterized in that: The first low-pass filter module (12) and the second low-pass filter module (22) share at least one inductor element.

4. The double protection lightning protection circuit according to claim 3 is characterized in that: The first low-pass filter module (12) comprises a first inductor element (121), a first input-side capacitor element (122) and a first output-side capacitor element (123); a first end of the first input-side capacitor element (122) is connected to a first end of the first inductor element (121); a second end of the first input-side capacitor element (122) is connected to the neutral line terminal (200); a first end of the first output-side capacitor element (123) is connected to a second end of the first inductor element (121); and a second end of the first output-side capacitor element (123) is connected to the neutral line terminal (200); The second low-pass filter module (22) comprises the first inductor element (121), a second input-side capacitor element (222) and a second output-side capacitor element (223), wherein a first end of the second input-side capacitor element (222) is connected to a first end of the first inductor element (121), a second end of the second input-side capacitor element (222) is connected to the ground terminal (300), a first end of the second output-side capacitor element (223) is connected to a second end of the first inductor element (121), and a second end of the second output-side capacitor element (223) is connected to the neutral terminal (200); The third low-pass filter module (32) comprises a third inductor element (321), a third input side capacitor element (322) and a third output side capacitor element (323); the first end of the third input side capacitor element (322) is connected to the first end of the third inductor element (321), the second end of the third input side capacitor element (322) is connected to the ground terminal (300), the first end of the third output side capacitor element (323) is connected to the second end of the third inductor element (321), and the second end of the third output side capacitor element (323) is connected to the ground terminal (300).

5. The double protection lightning protection circuit according to claim 4 is characterized in that: The first surge protection module (11) comprises a first input-side surge protector (111) and a first output-side surge protector (112); the first end of the first input-side surge protector (111) is connected to the first end of the first inductor element (121); the second end of the first input-side surge protector (111) is connected to the neutral line end (200); the first end of the first output-side surge protector (112) is connected to the second end of the first inductor element (121); and the second end of the first output-side surge protector (112) is connected to the neutral line end (200); The second surge protection module (21) comprises a second input-side surge protector (211) and a second output-side surge protector (212); the first end of the second input-side surge protector (211) is connected to the first end of the first inductor element (121), the second end of the second input-side surge protector (211) is connected to the ground terminal (300), the first end of the second output-side surge protector (212) is connected to the second end of the first inductor element (121), and the second end of the second output-side surge protector (212) is connected to the ground terminal (300); The third surge protection module (31) comprises a third input-side surge protector (311) and a third output-side surge protector (312); a first end of the third input-side surge protector (311) is connected to a first end of the third inductor element (321); a second end of the third input-side surge protector (311) is connected to a ground terminal (300); a first end of the third output-side surge protector (312) is connected to a second end of the third inductor element (321); and a second end of the third output-side surge protector (312) is connected to the ground terminal (300).

6. The double protection lightning protection circuit according to claim 5, characterized in that: The maximum continuous operating voltage of the first input-side surge protector (111) is greater than the maximum continuous operating voltage of the first output-side surge protector (112); The maximum continuous operating voltage of the second input-side surge protector (211) is greater than the maximum continuous operating voltage of the second output-side surge protector (212); The maximum continuous operating voltage of the third input-side surge protector (311) is greater than the maximum continuous operating voltage of the third output-side surge protector (312).

7. The double protection lightning protection circuit according to claim 5, characterized in that: The second ends of the first input-side capacitive element (122) and the first input-side surge protector (111) are connected to the first end of the third inductive element (321); The second ends of the first output-side capacitive element (123) and the first output-side surge protector (112) are connected to the second end of the third inductive element (321).

8. The double protection lightning protection circuit according to claim 7 is characterized in that: The ground terminal (300) comprises an input side ground terminal (310) and an output side ground terminal (320); The second input side capacitor element (222), the second input side surge protector (211), the third input side capacitor element (322) and the second end of the third input side surge protector (311) are connected to the input side ground terminal (310); The second output side capacitor element (223), the second output side surge protector (212), the third output side capacitor element (323) and the second end of the third output side surge protector (312) are connected to the output side ground terminal (320).

9. The double protection lightning protection circuit according to any one of claims 1 to 8, characterized in that: An inductive device is connected between the ground wire terminal (300) and the first common-mode discharge unit (2) and the second common-mode discharge unit (3).

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