Power supply filter

Abstract

The utility model discloses a power supply filter, comprising a filtering processing module, a grounding detection module and a transformation rectification module, the filtering processing module is respectively electrically connected with the grounding detection module, the transformation rectification module and a live wire, a zero wire and a ground wire in a power grid system, and the grounding detection module is also electrically connected with the ground wire and the transformation rectification module; the filtering processing module generates a second alternating-current signal and a target alternating-current signal for supplying power to the electric equipment based on the first alternating-current signal; the voltage transformation and rectification module converts the second alternating-current electric signal into a direct-current electric signal; the grounding detection module outputs a first level signal used for representing grounding abnormity so as to control the filtering processing module to stop outputting the target alternating current signal. By detecting the grounding condition of the electric equipment in the power grid system and stopping outputting the target alternating current signal to the electric equipment when the grounding abnormity is detected, the performance abnormity of the electric equipment caused by the grounding abnormity is avoided, and the safety and the reliability of the power grid system are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to a power supply filter. Background Art

[0002] At present, the use of various types of electrical equipment, such as industrial and civil, is becoming more and more frequent. In order to enhance the reliability of electrical equipment, effective grounding design is usually carried out for electrical equipment.

[0003] However, in the process of connecting various types of electrical equipment to the power grid system, due to factors such as improper operation, abnormal grounding occurs in the power grid system, seriously affecting the reliability and safety of the electrical equipment connected to the power grid system. Utility Model Content

[0004] The utility model provides a power supply filter, which is used to solve the problem of abnormal grounding in the existing power grid system and improve the safety and reliability of the power grid system and electrical equipment.

[0005] The utility model provides a power supply filter, comprising a filtering processing module, a grounding detection module and a transformer rectification module, wherein:

[0006] The filtering processing module is electrically connected to the grounding detection module, the transformer and rectifier module, and the live wire, the neutral wire and the ground wire in the power grid system respectively, and the grounding detection module is also electrically connected to the ground wire in the power grid system and the transformer and rectifier module;

[0007] The filtering processing module is used to generate a second alternating current signal and a target alternating current signal based on the first alternating current signal output by the power grid system, wherein the target alternating current signal is used to provide electric energy to the electric device;

[0008] The transformer and rectifier module is used to convert the second AC power signal into a DC power signal;

[0009] The grounding detection module is used to output a first level signal for characterizing that there is an electrical device with grounding abnormality in the power grid system when receiving the DC signal, so that the filtering processing module stops outputting the target AC signal after receiving the first level signal.

[0010] In an optional embodiment, the ground detection module includes a step-down unit, a rectification and filtering unit, and an isolation unit, wherein:

[0011] The first end of the step-down unit is electrically connected to the filtering processing module, and the second end of the step-down unit is electrically connected to the first end of the rectifying and filtering unit, for stepping down the second AC signal to obtain a third AC signal;

[0012] The second end of the rectifying and filtering unit is electrically connected to the first end of the isolation unit, and the third end of the rectifying and filtering unit is electrically connected to the ground wire in the power grid system and the second end of the isolation unit, respectively, for rectifying and filtering the third AC electric signal and outputting an intermediate electric signal;

[0013] The third end of the isolation unit is electrically connected to the transformer and rectifier module for receiving the DC signal, and the fourth end of the isolation unit is electrically connected to the filter processing module for outputting the first level signal;

[0014] The isolation unit is used to generate the first level signal according to the voltage difference of the intermediate electrical signal when receiving the direct current signal.

[0015] In an optional embodiment, the voltage reduction unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, and a second capacitor, wherein:

[0016] The first resistor, the second resistor and the third resistor are electrically connected in series, and the fourth resistor, the fifth resistor and the sixth resistor are electrically connected in series;

[0017] The first end of the first resistor and the first end of the fourth resistor are electrically connected to serve as the first end of the voltage reduction unit;

[0018] The second end of the third resistor is electrically connected to the second end of the sixth resistor, the first end of the first capacitor and the first end of the second capacitor respectively;

[0019] The second end of the first capacitor is electrically connected to the second end of the second capacitor to serve as the second end of the voltage reduction unit.

[0020] In an optional embodiment, the rectification and filtering unit includes a first diode, a second diode, a seventh resistor, an eighth resistor, a third capacitor and a fourth capacitor, wherein:

[0021] The anode of the first diode and the cathode of the second diode are electrically connected to serve as the first end of the rectifying and filtering unit;

[0022] The cathode of the first diode is electrically connected to the first end of the seventh resistor;

[0023] The second end of the seventh resistor is electrically connected to the first end of the eighth resistor and the first end of the third capacitor respectively;

[0024] The second end of the eighth resistor is electrically connected to the first end of the fourth capacitor to serve as the second end of the rectifying and filtering unit;

[0025] The anode of the second diode is electrically connected to the second end of the third capacitor and the second end of the fourth capacitor respectively, serving as the third end of the rectifying and filtering unit.

[0026] In an optional embodiment, the rectification and filtering unit further includes a first transient voltage suppression diode and a voltage regulator diode, wherein:

[0027] The first end of the first transient suppression diode is electrically connected to the cathode of the voltage stabilizing diode and the second end of the seventh resistor respectively;

[0028] The second end of the first transient voltage suppression diode is electrically connected to the anode of the voltage regulator diode and the anode of the second diode respectively.

[0029] In an optional embodiment, the isolation unit includes an optical coupler, a ninth resistor, a tenth resistor, a second transient voltage suppression diode and a fifth capacitor, wherein:

[0030] The first end of the optical coupler serves as the first end of the isolation unit, the second end of the optical coupler serves as the second end of the isolation unit, the third end of the optical coupler is electrically connected to the first end of the second transient suppression diode and the ground respectively, and the fourth end of the optical coupler is electrically connected to the first end of the ninth resistor;

[0031] The second end of the ninth resistor is electrically connected to the first end of the tenth resistor, the second end of the second transient suppression diode and the first end of the fifth capacitor respectively, serving as the fourth end of the isolation unit;

[0032] The second end of the tenth resistor serves as the third end of the isolation unit;

[0033] A second terminal of the fifth capacitor is grounded.

[0034] In an optional embodiment, the filtering processing module includes a lightning protection unit, a filtering unit and a switch unit, wherein:

[0035] The first end of the lightning protection unit is electrically connected to the live wire in the power grid system, the second end of the lightning protection unit is electrically connected to the neutral wire in the power grid system, the third end of the lightning protection unit is electrically connected to the first end of the filter unit, the fourth end of the lightning protection unit is electrically connected to the second end of the filter unit, and the fifth end of the lightning protection unit is electrically connected to the ground wire in the power grid system;

[0036] The lightning protection unit is used to generate the second alternating current signal according to the first alternating current signal;

[0037] The first end of the switch unit is electrically connected to the third end of the filter unit, the second end of the switch unit is electrically connected to the ground detection module, and is used to receive the first level signal, the third end of the switch unit is electrically connected to the transformer and rectifier module, and is used to receive the DC signal, and the fourth end of the switch unit and the fourth end of the filter unit are used to output the target AC signal;

[0038] The switch unit is configured to disconnect a path between the first end of the switch unit and the fourth end of the switch unit when receiving the direct current signal and the first level signal;

[0039] The filtering unit is used to filter the second AC power signal to generate the target AC power signal.

[0040] In an optional embodiment, the lightning protection unit includes a first thermistor, a first varistor, a second varistor, a third varistor and a first discharge tube, wherein:

[0041] The first end of the first varistor is electrically connected to the first end of the second varistor, serving as the first end and the third end of the lightning protection unit; the second end of the first varistor is electrically connected to the first end of the first thermistor and the first end of the third varistor, serving as the fourth end of the lightning protection unit;

[0042] The second end of the first thermistor serves as the second end of the lightning protection unit;

[0043] The second end of the second varistor is electrically connected to the second end of the third varistor and the first end of the first discharge tube respectively;

[0044] The second end of the first discharge tube serves as the fifth end of the lightning protection unit.

[0045] In an optional embodiment, the filtering unit includes an eleventh resistor, a twelfth resistor, a sixth capacitor, a seventh capacitor and a first filter, wherein:

[0046] The first end of the eleventh resistor is electrically connected to the first end of the sixth capacitor and the first end of the first filter respectively, serving as the first end of the filtering unit, and the second end of the eleventh resistor is electrically connected to the first end of the twelfth resistor;

[0047] The second end of the twelfth resistor is electrically connected to the second end of the sixth capacitor and the second end of the first filter respectively, serving as the second end of the filtering unit;

[0048] The third end of the first filter is electrically connected to the first end of the seventh capacitor as the third end of the filter unit, and the fourth end of the first filter is electrically connected to the second end of the seventh capacitor as the fourth end of the filter unit.

[0049] In an optional embodiment, the filtering unit further includes an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor and a second filter, wherein:

[0050] The first end of the eighth capacitor is electrically connected to the first end of the seventh capacitor and the first end of the second filter respectively, and the second end of the eighth capacitor is electrically connected to the first end of the ninth capacitor and the ground line in the power grid system respectively;

[0051] The second end of the ninth capacitor is electrically connected to the second end of the seventh capacitor and the second end of the second filter respectively;

[0052] The third end of the second filter is electrically connected to the first end of the tenth capacitor, serving as the third end of the filter unit, and the fourth end of the second filter is electrically connected to the first end of the eleventh capacitor, serving as the fourth end of the filter unit;

[0053] The second end of the tenth capacitor is electrically connected to the second end of the eleventh capacitor and a ground line in the power grid system respectively.

[0054] In an optional embodiment, the switch unit includes a second thermistor, a relay and a third diode, wherein:

[0055] The first end of the second thermistor serves as the first end of the switch unit, and the second end of the second thermistor is electrically connected to the first end of the relay;

[0056] The second end of the relay is electrically connected to the anode of the third diode as the second end of the switch unit, the third end of the relay is electrically connected to the cathode of the third diode as the third end of the switch unit, and the fourth end of the relay serves as the fourth end of the switch unit.

[0057] In an optional embodiment, the filtering processing module further includes a direct elimination unit;

[0058] The DC elimination unit is electrically connected between the lightning protection unit and the filtering unit, and is used to eliminate the DC component in the second AC power signal to obtain the target AC power signal.

[0059] In an optional embodiment, the direct current elimination unit includes a fourth diode, a fifth diode, a sixth diode, a seventh diode, a twelfth capacitor and a thirteenth capacitor, wherein:

[0060] The cathode of the fourth diode is electrically connected to the anode of the fifth diode, the first end of the twelfth capacitor and the third end of the lightning protection unit, and the anode of the fourth diode is electrically connected to the cathode of the fifth diode, the second end of the twelfth capacitor and the first end of the filtering unit;

[0061] The cathode of the sixth diode is electrically connected to the anode of the seventh diode, the first end of the thirteenth capacitor and the fourth end of the lightning protection unit, and the anode of the sixth diode is electrically connected to the cathode of the seventh diode, the second end of the thirteenth capacitor and the second end of the filtering unit.

[0062] In an optional embodiment, the filtering processing module further includes an indication unit;

[0063] The first end of the indicating unit is electrically connected to the fourth end of the switch unit, and the second end of the indicating unit is electrically connected to the fourth end of the filter unit;

[0064] The indicating unit is used to indicate whether the filtering processing module outputs the target AC power signal normally.

[0065] In an optional embodiment, the indicating unit includes a thirteenth resistor, a light emitting diode and an eighth diode, wherein:

[0066] The first end of the thirteenth resistor serves as the first end of the indicating unit, and the second end of the thirteenth resistor is electrically connected to the anode of the light emitting diode and the cathode of the eighth diode respectively;

[0067] The cathode of the light emitting diode is electrically connected to the anode of the eighth diode and serves as the second end of the indicating unit.

[0068] In an optional embodiment, the transformer and rectifier module includes an AC transformer, a second discharge tube, a bridge rectifier diode, a fourteenth capacitor, a fifteenth capacitor and a sixteenth capacitor, wherein:

[0069] The first end of the AC transformer and the second end of the AC transformer are used to input the second AC signal, the third end of the AC transformer is electrically connected to the first end of the second discharge tube and the first end of the bridge rectifier diode, respectively, and the fourth end of the AC transformer is electrically connected to the second end of the second discharge tube and the second end of the bridge rectifier diode, respectively;

[0070] The third end of the bridge rectifier diode is electrically connected to the first end of the fourteenth capacitor, the first end of the fifteenth capacitor and the first end of the sixteenth capacitor respectively, for outputting the DC signal;

[0071] The fourth end of the bridge rectifier diode is electrically connected to the second end of the fourteenth capacitor, the second end of the fifteenth capacitor, the second end of the sixteenth capacitor and the ground respectively.

[0072] The technical solution provided in the embodiments of the present utility model brings at least the following beneficial effects:

[0073] In the power supply filter provided by the utility model, a grounding detection module is set to detect the grounding condition of the electrical equipment connected to the power grid system, and when it is detected that there is an electrical equipment with abnormal grounding in the power grid system, a first level signal is output to the filtering processing module to control the filtering processing module to stop outputting the target AC power signal to the electrical equipment, thereby avoiding abnormal performance of the electrical equipment due to abnormal grounding, and improving the safety and reliability of the power grid system and the electrical equipment.

[0074] In addition, other features and advantages of the utility model will be described in the subsequent description, and partly become apparent from the description, or understood by practicing the utility model. The purpose and other advantages of the utility model can be achieved and obtained by the structures specifically pointed out in the written description, claims, and drawings. It should be understood that the above general description and the detailed description below are only exemplary and explanatory, and cannot limit the utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0076] Figure 1 A schematic diagram of the module structure of a power supply filter provided by an embodiment of the utility model;

[0077] Figure 2 A schematic diagram of the internal structure of a filtering processing module provided by an embodiment of the utility model;

[0078] Figure 3 A schematic diagram of the circuit structure of a filtering processing module provided by an embodiment of the utility model;

[0079] Figure 4 A schematic diagram of the circuit structure of a transformer and rectifier module provided in an embodiment of the utility model;

[0080] Figure 5 A schematic diagram of the internal structure of a ground detection module provided by an embodiment of the utility model;

[0081] Figure 6 A schematic diagram of the circuit structure of a ground detection module provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0082] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0083] The technical solution in the embodiment of the utility model will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiment of the utility model, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text is only a description of the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiment of the utility model, "multiple" means two or more than two.

[0084] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present utility model, unless otherwise specified, "plurality" means two or more.

[0085] A power filter is a circuit device installed at the back end of a power grid system to prevent electromagnetic interference from entering the grid and to prevent noise from entering the power grid.

[0086] However, due to the popularity of various types of electrical equipment such as industrial and civil use, the uncertainty and diversity of the above-mentioned interference have increased, and grounding abnormality is also a problem that needs to be urgently solved in the power grid system. Therefore, the existing power supply filters can no longer meet the actual use requirements of the power grid system, nor can they guarantee the reliability of the power grid system.

[0087] In view of the above problems, the utility model provides a power supply filter, which filters the AC power signal output by the power grid system and detects the grounding condition of the power equipment connected to the power grid system, thereby improving the safety and reliability of the power grid system and the power equipment.

[0088] Figure 1A schematic diagram of the module structure of a power supply filter provided by an embodiment of the utility model is shown. Figure 1 As shown, the power filter 10 includes a filtering processing module 11, a grounding detection module 12 and a transformer and rectifier module 13, wherein:

[0089] The filtering processing module 11 is electrically connected to the grounding detection module 12, the transformer and rectifier module 13, and the live wire (AC_IN_L), the neutral wire (AC_IN_N) and the ground wire (PE) in the power grid system respectively. The grounding detection module 12 is also electrically connected to the ground wire (PE) in the power grid system and the transformer and rectifier module 13;

[0090] The filtering processing module 11 is used to generate a second alternating current signal (AC_1, AC_n) and a target alternating current signal (AC_out_1, AC_out_n) based on the first alternating current signal (AC_in_1, AC_in_n) output by the power grid system, wherein the target alternating current signal (AC_out_1, AC_out_n) is used to provide electric energy for the electric device;

[0091] The transformer and rectifier module 13 is used to convert the second AC signal (AC_1, AC_n) into a DC signal Vcc;

[0092] The grounding detection module 12 is used to output a first level signal for indicating that there is an electrical device with grounding abnormality in the power grid system when receiving the DC signal Vcc, so that the filtering processing module 11 stops outputting the target AC signal (AC_out_l, AC_out_n) after receiving the first level signal.

[0093] In one or more embodiments, the grounding detection module 12 is also used to output a second level signal for characterizing that the grounding of the electrical equipment in the power grid system is normal when a DC signal is received, so that the filtering processing module 11 continues to output the target AC signal after receiving the second level signal.

[0094] In a specific implementation, the filtering processing module 11 processes the first AC power signal to obtain a second AC power signal, and outputs the second AC power signal to the transformer and rectifier module 13 and the grounding detection module 12, and obtains a target AC power signal, and outputs the target AC power signal to the electrical equipment to provide AC power to the electrical equipment.

[0095] The transformer and rectifier module 13 processes the received second AC power signal to obtain a DC power signal, and sends the DC power signal to the ground detection module 12 and the filter processing module 11 to provide DC power.

[0096] The grounding detection module 12 starts working after receiving the DC signal, and detects the voltage difference between the second AC signal and the ground line (PE) of the power grid system to determine whether there is an electrical device with abnormal grounding in the power grid system.

[0097] If the grounding detection module 12 detects that there is an abnormally grounded electrical device in the power grid system, it outputs a first level signal to the filtering processing module 11 to control the filtering processing module 11 to stop outputting the target AC signal, thereby stopping power supply to the electrical device, so that the electrical device stops working;

[0098] If the grounding detection module 12 does not detect any electrical equipment with abnormal grounding in the power grid system, it outputs a second level signal to the filtering processing module 11 to control the filtering processing module 11 to continuously output the target AC signal so that the electrical equipment can operate normally.

[0099] In one or more embodiments, the first level signal is a high level signal, and the second level signal is a low level signal.

[0100] By setting a grounding detection module in the power filter, the grounding condition of the electrical equipment connected to the power grid system is detected, and when it is detected that there is an electrical equipment with abnormal grounding in the power grid system, a first level signal is output to the filter processing module to control the filter processing module to stop outputting the target AC power signal to the electrical equipment, thereby avoiding abnormal performance of the electrical equipment due to abnormal grounding, and improving the safety and reliability of the power grid system and electrical equipment.

[0101] In an optional embodiment, if Figure 2 As shown, the filtering processing module 11 includes a lightning protection unit 111, a filtering unit 112 and a switch unit 113, wherein:

[0102] The first end of the lightning protection unit 111 is electrically connected to the live wire (AC_IN_L) in the power grid system, the second end of the lightning protection unit 111 is electrically connected to the neutral wire (AC_IN_N) in the power grid system, the third end of the lightning protection unit 111 is electrically connected to the first end of the filter unit 112, the fourth end of the lightning protection unit 111 is electrically connected to the second end of the filter unit, and the fifth end of the lightning protection unit 111 is electrically connected to the ground wire (PE) in the power grid system;

[0103] The first end of the switch unit 113 is electrically connected to the third end of the filter unit 112, the second end of the switch unit 113 is electrically connected to the ground detection module 12, and is used to receive the first level signal, the third end of the switch unit 113 is electrically connected to the transformer and rectifier module 13, and is used to receive a DC signal, and the fourth end of the switch unit 113 and the fourth end of the filter unit 112 are used to output a target AC signal;

[0104] The lightning protection unit 111 is used to generate a second alternating current signal (AC_1, AC_n) according to the first alternating current signal (AC_in_1, AC_in_n);

[0105] The switch unit 113 is used to disconnect the path between the first end of the switch unit 113 and the fourth end of the switch unit 113 when receiving the DC signal Vcc and the first level signal;

[0106] The filtering unit 112 is used to filter the second alternating current signal (AC_1, AC_n) to generate a target alternating current signal (AC_out_1, AC_out_n).

[0107] In one or more embodiments, the switch unit 113 is further configured to conduct a path between the first end of the switch unit 113 and the fourth end of the switch unit 113 when receiving the DC signal Vcc and the second level signal.

[0108] In an optional embodiment, if Figure 2 As shown, the filtering processing module 11 further includes a direct elimination unit 114;

[0109] The DC elimination unit 114 is electrically connected between the lightning protection unit 111 and the filtering unit 112, and is used to eliminate the DC component in the second AC power signal (AC_1, AC_n) to obtain the target AC power signal (AC_out_1, AC_out_n).

[0110] In a specific implementation, after the lightning protection unit 111 receives the first AC signal (AC_in_1, AC_in_n) output by the power grid system, it processes it and outputs the second AC signal (AC_1, AC_n) to the DC elimination unit 114; after the DC elimination unit 114 receives the second AC signal (AC_1, AC_n), it eliminates the DC component in the second AC signal (AC_1, AC_n), and sends the AC signal with the DC component eliminated to the filtering unit 112; the filtering unit 112 performs EMI (Electromagnetic Interference) filtering on the AC signal with the DC component eliminated, and outputs the target AC signal (AC_out_1, AC_out_n);

[0111] When the switch unit 113 receives the second level signal, the path between the first end of the switch unit 113 and the fourth end of the switch unit 113 is turned on, and the target AC power signal (AC_out_l, AC_out_n) is sent to the corresponding electrical equipment to supply power to the electrical equipment; when the switch unit 113 receives the first level signal, the path between the first end of the switch unit 113 and the fourth end of the switch unit 113 is turned off, and the target AC power signal (AC_out_l, AC_out_n) cannot be sent to the corresponding electrical equipment, and the electrical equipment stops working.

[0112] In an optional embodiment, if Figure 2 As shown, the filtering processing module 11 further includes an indication unit 115;

[0113] A first end of the indicating unit 115 is electrically connected to a fourth end of the switching unit 113, and a second end of the indicating unit 115 is electrically connected to a fourth end of the filtering unit 112;

[0114] The indicating unit 115 is used to indicate whether the filtering processing module 11 outputs the target AC power signal (AC_out_1, AC_out_n) normally.

[0115] In a specific implementation, when the fourth end of the switch unit 113 outputs the target AC signal (AC_out_1, AC_out_n), the indication unit 115 generates a first indication signal to inform the staff that each electrical device in the power grid system is normally grounded. At this time, the target AC signal (AC_out_1, AC_out_n) is output normally, and the electrical device works normally;

[0116] When the fourth end of the switch unit 113 cannot output the target AC signal (AC_out_l, AC_out_n), the indication unit 115 generates a second indication signal to inform the staff that there is an electrical equipment with abnormal grounding in the power grid system. At this time, the target AC signal (AC_out_l, AC_out_n) stops being output and the electrical equipment stops working.

[0117] In an optional embodiment, if Figure 3 As shown, the lightning protection unit 111 includes a first thermistor RT1, a first varistor RV1, a second varistor RV2, a third varistor RV3 and a first discharge tube GDT1, wherein:

[0118] The first end of the first varistor RV1 is electrically connected to the first end of the second varistor RV2, serving as the first end and the third end of the lightning protection unit 111. The second end of the first varistor RV1 is electrically connected to the first end of the first thermistor RT1 and the first end of the third varistor RV3, serving as the fourth end of the lightning protection unit 111.

[0119] The second end of the first thermistor RT1 serves as the second end of the lightning protection unit 111;

[0120] The second end of the second varistor RV2 is electrically connected to the second end of the third varistor RV3 and the first end of the first discharge tube GDT1 respectively;

[0121] The second end of the first discharge tube GDT1 serves as the fifth end of the lightning protection unit 111 .

[0122] In one or more embodiments, the first discharge tube GDT1 is a gas discharge tube.

[0123] In an optional embodiment, if Figure 3 As shown, the DC elimination unit 114 includes a fourth diode D4, a fifth diode D5, a sixth diode D6, a seventh diode D7, a twelfth capacitor C12 and a thirteenth capacitor C13, wherein:

[0124] The cathode of the fourth diode D4 is electrically connected to the anode of the fifth diode D5, the first end of the twelfth capacitor C12 and the third end of the lightning protection unit 111, and the anode of the fourth diode D4 is electrically connected to the cathode of the fifth diode D5, the second end of the twelfth capacitor C12 and the first end of the filter unit 112;

[0125] The cathode of the sixth diode D6 is electrically connected to the anode of the seventh diode D7, the first end of the thirteenth capacitor C13 and the fourth end of the lightning protection unit 111, and the anode of the sixth diode D6 is electrically connected to the cathode of the seventh diode D7, the second end of the thirteenth capacitor C13 and the second end of the filtering unit 112.

[0126] In one or more embodiments, the twelfth capacitor C12 and the thirteenth capacitor C13 are both polarized capacitors, wherein the first end of the twelfth capacitor C12 is the positive electrode of the twelfth capacitor C12, and the second end of the twelfth capacitor C12 is the negative electrode of the twelfth capacitor C12; the first end of the thirteenth capacitor C13 is the positive electrode of the thirteenth capacitor C13, and the second end of the thirteenth capacitor C13 is the negative electrode of the thirteenth capacitor C13.

[0127] In actual use, if there is an inductive load in the electrical equipment, for example, the electrical equipment is a transformer, the DC component in the AC signal will cause magnetic saturation in the inductive load, thereby causing the temperature of the electrical equipment to rise, or even causing a short circuit in the electrical equipment, etc. Therefore, a DC elimination unit 114 is added to the power filter provided by the utility model to eliminate the DC component in the second AC signal (AC_l, AC_n) to avoid damage to the inductive load caused by the DC component, thereby ensuring the safety of the power system.

[0128] In an optional embodiment, if Figure 3 As shown, the filtering unit 112 includes an eleventh resistor R11, a twelfth resistor R12, a sixth capacitor C6, a seventh capacitor C7, a first filter FIL1, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11 and a second filter FIL2, wherein:

[0129] The first end of the eleventh resistor R11 is electrically connected to the first end of the sixth capacitor C6 and the first end of the first filter FIL1 respectively, serving as the first end of the filter unit 112, and the second end of the eleventh resistor R11 is electrically connected to the first end of the twelfth resistor R12;

[0130] The second end of the twelfth resistor R12 is electrically connected to the second end of the sixth capacitor C6 and the second end of the first filter FIL1 respectively, and serves as the second end of the filter unit 112;

[0131] The third end of the first filter FIL1 is electrically connected to the first end of the seventh capacitor C7, the first end of the eighth capacitor C8, and the first end of the second filter FIL2, respectively; the fourth end of the first filter FIL1 is electrically connected to the second end of the seventh capacitor C7, the second end of the ninth capacitor C9, and the second end of the second filter FIL2, respectively;

[0132] The second end of the eighth capacitor C8 is electrically connected to the first end of the ninth capacitor C9 and the ground line (PE) in the power grid system respectively;

[0133] The third end of the second filter FIL2 is electrically connected to the first end of the tenth capacitor C10, serving as the third end of the filter unit 112; the fourth end of the second filter FIL2 is electrically connected to the first end of the eleventh capacitor C11, serving as the fourth end of the filter unit 112;

[0134] The second end of the tenth capacitor C10 is electrically connected to the second end of the eleventh capacitor C11 and the ground line (PE) in the power grid system respectively.

[0135] In a specific implementation, the eleventh resistor R11, the twelfth resistor R12, the sixth capacitor C6, the seventh capacitor C7 and the first filter FIL1 constitute a first-stage π-type filter circuit, and the eighth capacitor C8, the ninth capacitor C9, the tenth capacitor C10, the eleventh capacitor C11 and the second filter FIL2 constitute a second-stage π-type filter circuit; the AC signal with the DC component eliminated is subjected to EMI filtering processing by means of two-stage π-type filter circuits connected in series to obtain the target AC signal (AC_out_l, AC_out_n).

[0136] In an optional embodiment, if Figure 3 As shown, the switch unit 113 includes a second thermistor RT2, a relay JK1 and a third diode D3, wherein:

[0137] The first end of the second thermistor RT2 serves as the first end of the switch unit 113, and the second end of the second thermistor RT2 is electrically connected to the first end of the relay JK1;

[0138] The second end of the relay JK1 is electrically connected to the anode of the third diode D3, serving as the second end of the switch unit 113. The third end of the relay JK1 is electrically connected to the cathode of the third diode D3, serving as the third end of the switch unit 113. The fourth end of the relay JK1 serves as the fourth end of the switch unit 113.

[0139] In one or more embodiments, the relay JK1 is a power relay.

[0140] In a specific implementation, the relay JK1 in the switch unit 113 starts working after receiving the DC signal Vcc output by the transformer-rectifier module 13; when the second end of the relay JK1 receives a first level signal, the path between the first end and the fourth end of the relay JK1 is disconnected, that is, the relay JK1 is disconnected, and at this time, the target AC signal (AC_out_l, AC_out_n) cannot be transmitted to the subsequent electrical equipment; when the second end of the relay JK1 receives a second level signal, the path between the first end and the fourth end of the relay JK1 is connected, that is, the relay JK1 is turned on, and at this time, the target AC signal (AC_out_l, AC_out_n) is transmitted to the subsequent electrical equipment through the relay JK1 to power the electrical equipment.

[0141] In an optional embodiment, if Figure 3 As shown, the indicating unit 115 includes a thirteenth resistor R13, a light emitting diode LED1 and an eighth diode D8, wherein:

[0142] A first end of the thirteenth resistor R13 serves as a first end of the indicating unit 115, and a second end of the thirteenth resistor R13 is electrically connected to the anode of the light emitting diode LED1 and the cathode of the eighth diode D8 respectively;

[0143] The cathode of the light emitting diode LED1 is electrically connected to the anode of the eighth diode D8 , serving as the second end of the indicating unit 115 .

[0144] In a specific implementation, when the fourth end of relay JK1 outputs the target AC signal (AC_out_l, AC_out_n), the light-emitting diode LED1 emits light, i.e., generates a first indication signal to inform the staff that each electrical device in the power grid system is normally grounded; when the fourth end of relay JK1 stops outputting the target AC signal (AC_out_l, AC_out_n), the light-emitting diode LED1 does not emit light, i.e., generates a second indication signal to inform the staff that there are electrical devices with abnormal grounding in the power grid system.

[0145] In an optional embodiment, if Figure 4 As shown, the transformer-rectifier module 13 includes an AC transformer T1, a second discharge tube TSS1, a bridge rectifier diode DD1, a fourteenth capacitor C14, a fifteenth capacitor C15 and a sixteenth capacitor C16, wherein:

[0146] The first end of the AC transformer T1 and the second end of the AC transformer T1 are used to input a second AC signal (AC_1, AC_n), the third end of the AC transformer T1 is electrically connected to the first end of the second discharge tube TSS1 and the first end of the bridge rectifier diode DD1, respectively, and the fourth end of the AC transformer T1 is electrically connected to the second end of the second discharge tube TSS1 and the second end of the bridge rectifier diode DD1, respectively;

[0147] The third end of the bridge rectifier diode DD1 is electrically connected to the first end of the fourteenth capacitor C14, the first end of the fifteenth capacitor C15 and the first end of the sixteenth capacitor C16, respectively, for outputting a direct current signal Vcc;

[0148] The fourth end of the bridge rectifier diode DD1 is electrically connected to the second end of the fourteenth capacitor C14, the second end of the fifteenth capacitor C15, the second end of the sixteenth capacitor C16 and the ground respectively.

[0149] In one or more embodiments, the second discharge tube TSS1 is a semiconductor discharge tube.

[0150] In one or more embodiments, the fourteenth capacitor C14 is a polarized capacitor, wherein the first end of the fourteenth capacitor C14 is the positive electrode of the fourteenth capacitor C14, and the second end of the fourteenth capacitor C14 is the negative electrode of the fourteenth capacitor C14.

[0151] In a specific implementation, after receiving the second AC signal (AC_l, AC_n), the AC transformer T1 performs a voltage reduction process on it, for example, converting the 220V second AC signal (AC_l, AC_n) into a 4V AC signal; then, the AC signal after the voltage reduction process is full-wave rectified by the bridge rectifier diode DD1; finally, after filtering by the filtering circuit composed of the fourteenth capacitor C14, the fifteenth capacitor C15 and the sixteenth capacitor C16, a DC signal Vcc is output, for example, the output DC signal Vcc is 5V.

[0152] In an optional embodiment, if Figure 5 As shown, the ground detection module 12 includes a step-down unit 121, a rectifier and filter unit 122, and an isolation unit 123, wherein:

[0153] The first end of the step-down unit 121 is electrically connected to the filtering processing module 11, and the second end of the step-down unit 121 is electrically connected to the first end of the rectifying and filtering unit 122;

[0154] The second end of the rectifying and filtering unit 122 is electrically connected to the first end of the isolating unit 123, and the third end of the rectifying and filtering unit 122 is electrically connected to the ground wire (PE) in the power grid system and the second end of the isolating unit 123 respectively;

[0155] The third end of the isolation unit 123 is electrically connected to the transformer and rectifier module 13 for receiving a DC signal, and the fourth end of the isolation unit 123 is electrically connected to the filter processing module 11 for outputting a first level signal;

[0156] The voltage reduction unit 121 is used to reduce the voltage of the second alternating current signal (AC_1, AC_n) to obtain a third alternating current signal;

[0157] The rectifying and filtering unit 122 is used to rectify and filter the third AC electric signal and output an intermediate electric signal;

[0158] The isolation unit 123 is configured to generate a first level signal according to the voltage difference of the intermediate electrical signal when receiving the direct current signal Vcc.

[0159] In one or more embodiments, the isolation unit 123 is further configured to generate a second level signal according to the voltage difference of the intermediate electrical signal when a direct current signal is received.

[0160] In a specific implementation, if the electrical equipment is grounded normally, a loop is formed between the first end of the isolation unit 123 and the second end of the isolation unit 123, and a voltage difference is formed between the intermediate signal received by the first end of the isolation unit 123 and the ground wire (PE) connected to the second end of the isolation unit 123, so that the path between the third end of the isolation unit 123 and the fourth end of the isolation unit 123 is turned on, and the fourth end of the isolation unit 123 outputs the second level signal to the filtering processing module 11;

[0161] If the grounding of the electrical equipment is abnormal, a loop cannot be formed between the first end of the isolation unit 123 and the second end of the isolation unit 123, and a voltage difference cannot be formed between the intermediate signal received by the first end of the isolation unit 123 and the ground wire (PE) connected to the second end of the isolation unit 123. The path between the third end of the isolation unit 123 and the fourth end of the isolation unit 123 cannot be conducted, and the fourth end of the isolation unit 123 outputs a first level signal to the filtering processing module 11.

[0162] In an optional embodiment, if Figure 6 As shown, the voltage reduction unit 121 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first capacitor C1 and a second capacitor C2, wherein:

[0163] The first resistor R1, the second resistor R2 and the third resistor R3 are electrically connected in series, and the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6 are electrically connected in series;

[0164] A first end of the first resistor R1 and a first end of the fourth resistor R4 are electrically connected to serve as a first end of the voltage reduction unit 121;

[0165] The second end of the third resistor R3 is electrically connected to the second end of the sixth resistor R6, the first end of the first capacitor C1 and the first end of the second capacitor C2 respectively;

[0166] The second end of the first capacitor C1 is electrically connected to the second end of the second capacitor C2 and serves as the second end of the voltage reduction unit 121 .

[0167] In a specific implementation, after the second alternating current signal AC_1 passes through the voltage reduction unit 121, a resistance-capacitance voltage reduction process is performed to obtain a third alternating current signal.

[0168] In an optional embodiment, if Figure 6 As shown, the rectifying and filtering unit 122 includes a first diode D1, a second diode D2, a seventh resistor R7, an eighth resistor R8, a third capacitor C3, a fourth capacitor C4, a first transient voltage suppressor (TVS) diode TVS1 and a voltage regulator diode ZD, wherein:

[0169] The anode of the first diode D1 and the cathode of the second diode D2 are electrically connected to serve as the first end of the rectifying and filtering unit 122;

[0170] The cathode of the first diode D1 is electrically connected to the first end of the seventh resistor R7;

[0171] The second end of the seventh resistor R7 is electrically connected to the first end of the first transient suppression diode TVS1, the cathode of the voltage stabilizing diode ZD, the first end of the eighth resistor R8 and the first end of the third capacitor C3 respectively;

[0172] The second end of the eighth resistor R8 is electrically connected to the first end of the fourth capacitor C4 to serve as the second end of the rectifying and filtering unit 122;

[0173] The anode of the second diode D2 is electrically connected to the second end of the first transient suppression diode TVS1 , the anode of the voltage stabilizing diode ZD, the second end of the third capacitor C3 and the second end of the fourth capacitor C4 , respectively, to serve as the third end of the rectifying and filtering unit 122 .

[0174] In a specific implementation, the first diode D1 and the second diode D2 form a half-wave rectifier circuit to rectify the third AC electrical signal output by the step-down unit 121; the first transient suppression diode TVS1 and the voltage stabilizing diode ZD form a voltage stabilizing circuit to stabilize the electrical signal after rectification; the eighth resistor R8, the third capacitor C3 and the fourth capacitor C4 form a filter circuit to filter the electrical signal after voltage stabilization to obtain an intermediate electrical signal.

[0175] In an optional embodiment, if Figure 6 As shown, the isolation unit 123 includes an optical coupler U1, a ninth resistor R9, a tenth resistor R10, a second transient suppression diode TVS2 and a fifth capacitor C5, wherein:

[0176] The first end of the optical coupler U1 serves as the first end of the isolation unit 123, the second end of the optical coupler U1 serves as the second end of the isolation unit 123, the third end of the optical coupler U1 is electrically connected to the first end of the second transient suppression diode TVS2 and the ground respectively, and the fourth end of the optical coupler U1 is electrically connected to the first end of the ninth resistor R9;

[0177] The second end of the ninth resistor R9 is electrically connected to the first end of the tenth resistor R10, the second end of the second transient suppression diode TVS2 and the first end of the fifth capacitor C5, respectively, as the fourth end of the isolation unit 123;

[0178] The second end of the tenth resistor R10 serves as the third end of the isolation unit 123;

[0179] A second terminal of the fifth capacitor C5 is grounded.

[0180] In a specific implementation, when the electrical device is normally grounded, a voltage difference is formed between the first end of the optocoupler U1 and the second end of the optocoupler U1, so that the light-emitting diode inside the optocoupler U1 emits light to conduct the path between the third end of the optocoupler U1 and the fourth end of the optocoupler U1, that is, the optocoupler U1 is turned on. At this time, the level signal GND_TECT outputted by the fourth end of the isolation unit 123 is a second level signal;

[0181] When the electrical equipment is grounded abnormally, a voltage difference cannot be formed between the first end of the optocoupler U1 and the second end of the optocoupler U1, and the light-emitting diode inside the optocoupler U1 cannot emit light. The path between the third end of the optocoupler U1 and the fourth end of the optocoupler U1 cannot be conducted, that is, the optocoupler U1 cannot be conducted. At this time, the level signal GND_TECT outputted by the fourth end of the isolation unit 123 is a first level signal.

[0182] In addition to the filtering function, the above-mentioned power filter also has added direct current elimination function and grounding detection function. On the one hand, by adding a direct current elimination unit, the direct current component in the alternating current signal is filtered out to avoid the direct current component from causing damage to electrical equipment with inductive loads, thereby ensuring the safety of the power system. On the other hand, when there are electrical equipment with abnormal grounding in the power grid system, the light-emitting diode LED1 does not emit light, and the subsequent electrical equipment stops working; when the electrical equipment in the power grid system is normally grounded, the light-emitting diode LED1 emits light, and the subsequent electrical equipment works normally. Through the above-mentioned settings, the safety hazards of the power grid system caused by abnormal grounding are avoided, and the safety and reliability of the power grid system and electrical equipment are improved.

[0183] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A power supply filter, characterized in that: It includes a filtering processing module, a grounding detection module and a transformer and rectifier module, wherein: The filtering processing module is electrically connected to the grounding detection module, the transformer and rectifier module, and the live wire, the neutral wire and the ground wire in the power grid system respectively, and the grounding detection module is also electrically connected to the ground wire in the power grid system and the transformer and rectifier module; The filtering processing module is used to generate a second alternating current signal and a target alternating current signal based on the first alternating current signal output by the power grid system, wherein the target alternating current signal is used to provide electric energy to the electric device; The transformer and rectifier module is used to convert the second AC power signal into a DC power signal; The grounding detection module is used to output a first level signal for characterizing that there is an electrical device with grounding abnormality in the power grid system when receiving the DC signal, so that the filtering processing module stops outputting the target AC signal after receiving the first level signal.

2. The power supply filter according to claim 1, characterized in that: The ground detection module includes a step-down unit, a rectification and filtering unit, and an isolation unit, wherein: The first end of the step-down unit is electrically connected to the filtering processing module, and the second end of the step-down unit is electrically connected to the first end of the rectifying and filtering unit, for stepping down the second AC signal to obtain a third AC signal; The second end of the rectifying and filtering unit is electrically connected to the first end of the isolation unit, and the third end of the rectifying and filtering unit is electrically connected to the ground wire in the power grid system and the second end of the isolation unit, respectively, for rectifying and filtering the third AC electric signal and outputting an intermediate electric signal; The third end of the isolation unit is electrically connected to the transformer and rectifier module for receiving the DC signal, and the fourth end of the isolation unit is electrically connected to the filter processing module for outputting the first level signal; The isolation unit is used to generate the first level signal according to the voltage difference of the intermediate electrical signal when receiving the direct current signal.

3. The power supply filter according to claim 2, characterized in that: The voltage reduction unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor and a second capacitor, wherein: The first resistor, the second resistor and the third resistor are electrically connected in series, and the fourth resistor, the fifth resistor and the sixth resistor are electrically connected in series; The first end of the first resistor and the first end of the fourth resistor are electrically connected to serve as the first end of the voltage reduction unit; The second end of the third resistor is electrically connected to the second end of the sixth resistor, the first end of the first capacitor and the first end of the second capacitor respectively; The second end of the first capacitor is electrically connected to the second end of the second capacitor to serve as the second end of the voltage reduction unit.

4. The power supply filter according to claim 2, characterized in that: The rectifying and filtering unit comprises a first diode, a second diode, a seventh resistor, an eighth resistor, a third capacitor and a fourth capacitor, wherein: The anode of the first diode and the cathode of the second diode are electrically connected to serve as the first end of the rectifying and filtering unit; The cathode of the first diode is electrically connected to the first end of the seventh resistor; The second end of the seventh resistor is electrically connected to the first end of the eighth resistor and the first end of the third capacitor respectively; The second end of the eighth resistor is electrically connected to the first end of the fourth capacitor to serve as the second end of the rectifying and filtering unit; The anode of the second diode is electrically connected to the second end of the third capacitor and the second end of the fourth capacitor respectively, serving as the third end of the rectifying and filtering unit.

5. The power supply filter according to claim 4, characterized in that: The rectifying and filtering unit further includes a first transient suppression diode and a voltage regulator diode, wherein: The first end of the first transient suppression diode is electrically connected to the cathode of the voltage stabilizing diode and the second end of the seventh resistor respectively; The second end of the first transient voltage suppression diode is electrically connected to the anode of the voltage regulator diode and the anode of the second diode respectively.

6. The power supply filter according to claim 2, characterized in that: The isolation unit includes an optical coupler, a ninth resistor, a tenth resistor, a second transient suppression diode and a fifth capacitor, wherein: The first end of the optical coupler serves as the first end of the isolation unit, the second end of the optical coupler serves as the second end of the isolation unit, the third end of the optical coupler is electrically connected to the first end of the second transient suppression diode and the ground respectively, and the fourth end of the optical coupler is electrically connected to the first end of the ninth resistor; The second end of the ninth resistor is electrically connected to the first end of the tenth resistor, the second end of the second transient suppression diode and the first end of the fifth capacitor respectively, serving as the fourth end of the isolation unit; The second end of the tenth resistor serves as the third end of the isolation unit; A second terminal of the fifth capacitor is grounded.

7. The power supply filter according to claim 1, characterized in that: The filtering processing module includes a lightning protection unit, a filtering unit and a switch unit, wherein: The first end of the lightning protection unit is electrically connected to the live wire in the power grid system, the second end of the lightning protection unit is electrically connected to the neutral wire in the power grid system, the third end of the lightning protection unit is electrically connected to the first end of the filter unit, the fourth end of the lightning protection unit is electrically connected to the second end of the filter unit, and the fifth end of the lightning protection unit is electrically connected to the ground wire in the power grid system; The lightning protection unit is used to generate the second alternating current signal according to the first alternating current signal; The first end of the switch unit is electrically connected to the third end of the filter unit, the second end of the switch unit is electrically connected to the ground detection module, and is used to receive the first level signal, the third end of the switch unit is electrically connected to the transformer and rectifier module, and is used to receive the DC signal, and the fourth end of the switch unit and the fourth end of the filter unit are used to output the target AC signal; The switch unit is configured to disconnect a path between the first end of the switch unit and the fourth end of the switch unit when receiving the direct current signal and the first level signal; The filtering unit is used to filter the second AC power signal to generate the target AC power signal.

8. The power supply filter according to claim 7, characterized in that: The lightning protection unit includes a first thermistor, a first varistor, a second varistor, a third varistor and a first discharge tube, wherein: The first end of the first varistor is electrically connected to the first end of the second varistor, serving as the first end and the third end of the lightning protection unit; the second end of the first varistor is electrically connected to the first end of the first thermistor and the first end of the third varistor, serving as the fourth end of the lightning protection unit; The second end of the first thermistor serves as the second end of the lightning protection unit; The second end of the second varistor is electrically connected to the second end of the third varistor and the first end of the first discharge tube respectively; The second end of the first discharge tube serves as the fifth end of the lightning protection unit.

9. The power supply filter according to claim 7, characterized in that: The filtering unit includes an eleventh resistor, a twelfth resistor, a sixth capacitor, a seventh capacitor and a first filter, wherein: The first end of the eleventh resistor is electrically connected to the first end of the sixth capacitor and the first end of the first filter respectively, serving as the first end of the filtering unit, and the second end of the eleventh resistor is electrically connected to the first end of the twelfth resistor; The second end of the twelfth resistor is electrically connected to the second end of the sixth capacitor and the second end of the first filter respectively, serving as the second end of the filtering unit; The third end of the first filter is electrically connected to the first end of the seventh capacitor as the third end of the filter unit, and the fourth end of the first filter is electrically connected to the second end of the seventh capacitor as the fourth end of the filter unit.

10. The power supply filter according to claim 9, characterized in that: The filtering unit further includes an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, and a second filter, wherein: The first end of the eighth capacitor is electrically connected to the first end of the seventh capacitor and the first end of the second filter respectively, and the second end of the eighth capacitor is electrically connected to the first end of the ninth capacitor and the ground line in the power grid system respectively; The second end of the ninth capacitor is electrically connected to the second end of the seventh capacitor and the second end of the second filter respectively; The third end of the second filter is electrically connected to the first end of the tenth capacitor, serving as the third end of the filter unit, and the fourth end of the second filter is electrically connected to the first end of the eleventh capacitor, serving as the fourth end of the filter unit; The second end of the tenth capacitor is electrically connected to the second end of the eleventh capacitor and a ground line in the power grid system respectively.

11. The power supply filter according to claim 7, characterized in that: The switch unit comprises a second thermistor, a relay and a third diode, wherein: The first end of the second thermistor serves as the first end of the switch unit, and the second end of the second thermistor is electrically connected to the first end of the relay; The second end of the relay is electrically connected to the anode of the third diode as the second end of the switch unit, the third end of the relay is electrically connected to the cathode of the third diode as the third end of the switch unit, and the fourth end of the relay serves as the fourth end of the switch unit.

12. The power supply filter according to claim 7, characterized in that: The filtering processing module also includes a direct elimination unit; The DC elimination unit is electrically connected between the lightning protection unit and the filtering unit, and is used to eliminate the DC component in the second AC power signal to obtain the target AC power signal.

13. The power supply filter according to claim 12, characterized in that: The direct current elimination unit comprises a fourth diode, a fifth diode, a sixth diode, a seventh diode, a twelfth capacitor and a thirteenth capacitor, wherein: The cathode of the fourth diode is electrically connected to the anode of the fifth diode, the first end of the twelfth capacitor and the third end of the lightning protection unit, and the anode of the fourth diode is electrically connected to the cathode of the fifth diode, the second end of the twelfth capacitor and the first end of the filtering unit; The cathode of the sixth diode is electrically connected to the anode of the seventh diode, the first end of the thirteenth capacitor and the fourth end of the lightning protection unit, and the anode of the sixth diode is electrically connected to the cathode of the seventh diode, the second end of the thirteenth capacitor and the second end of the filtering unit.

14. The power supply filter according to claim 7 or 12, characterized in that: The filtering processing module also includes an indication unit; The first end of the indicating unit is electrically connected to the fourth end of the switch unit, and the second end of the indicating unit is electrically connected to the fourth end of the filter unit; The indicating unit is used to indicate whether the filtering processing module outputs the target AC power signal normally.

15. The power supply filter according to claim 14, characterized in that: The indicating unit includes a thirteenth resistor, a light emitting diode and an eighth diode, wherein: The first end of the thirteenth resistor serves as the first end of the indicating unit, and the second end of the thirteenth resistor is electrically connected to the anode of the light emitting diode and the cathode of the eighth diode respectively; The cathode of the light emitting diode is electrically connected to the anode of the eighth diode and serves as the second end of the indicating unit.

16. The power supply filter according to claim 1, characterized in that: The transformer and rectifier module includes an AC transformer, a second discharge tube, a bridge rectifier diode, a fourteenth capacitor, a fifteenth capacitor and a sixteenth capacitor, wherein: The first end of the AC transformer and the second end of the AC transformer are used to input the second AC signal, the third end of the AC transformer is electrically connected to the first end of the second discharge tube and the first end of the bridge rectifier diode, respectively, and the fourth end of the AC transformer is electrically connected to the second end of the second discharge tube and the second end of the bridge rectifier diode, respectively; The third end of the bridge rectifier diode is electrically connected to the first end of the fourteenth capacitor, the first end of the fifteenth capacitor and the first end of the sixteenth capacitor respectively, for outputting the DC signal; The fourth end of the bridge rectifier diode is electrically connected to the second end of the fourteenth capacitor, the second end of the fifteenth capacitor, the second end of the sixteenth capacitor and the ground respectively.

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