B-type leakage protection circuit breaker

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By using a combination of leakage transformer and multi-stage Butterworth low-pass filter in the leakage protection circuit breaker, the problem of difficulty in detecting complex leakage currents in the prior art is solved, and high-precision and rapid leakage detection are achieved, ensuring the safety of power supply equipment.

CN222966714UActive Publication Date: 2025-06-10INNUO POWER TECHNOLOGY (TIANJIN) CO LTD

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Patent Information

Application Number: CN202421731625.0
Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner
Filing Date: 2024-07-22
Publication Date: 2025-06-10
Estimated Expiration: 2034-07-22

AI Technical Summary

Technical Problem

Existing leakage protection circuit breakers are difficult to accurately detect complex leakage currents, especially in power supply equipment containing DC components, where detection accuracy and response speed are insufficient.

Method used

A B-type leakage protection circuit breaker is designed, using a leakage transformer in the signal acquisition module to couple the leakage current to the excitation current, and filtering out high-frequency components through a multi-stage Butterworth low-pass filter in the signal processing module, retaining the low-frequency components, and improving detection accuracy and response speed.

Benefits of technology

Accurate detection of complex leakage currents is achieved, detection accuracy and response speed are improved, malfunctions are reduced, and the safety and reliability of the power consumption environment is ensured.

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Abstract

The utility model discloses a B-type leakage protection circuit breaker, which comprises a master control module, a signal acquisition module, a signal processing module, a power supply module and a tripping module, the signal acquisition module comprises an electric leakage mutual inductor, an annular magnetic core of the electric leakage mutual inductor penetrates through a live wire and a zero wire of a power supply circuit to sense leakage current, and the leakage current is coupled to excitation current; the signal processing module comprises an operational amplifier U1B, an operational amplifier U2A, an operational amplifier U2B, an operational amplifier U2C, an operational amplifier U3A and an operational amplifier U3B; the operational amplifier U1B processes the excitation voltage signal, and the operational amplifiers U2A, U2B and U2C form a three-stage low-pass filter for filtering high-frequency components in the excitation voltage signal to obtain a leakage voltage signal; and the leakage voltage signal is raised to the magnitude which can be detected by an A / D converter of the main control module through the operational amplifiers U3A and U3B. The circuit breaker realizes the detection of complex leakage current by detecting excitation current, and has the advantages of higher response speed and lower misoperation possibility.

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Description

Technical Field

[0001] The utility model relates to the technical field of electrical safety equipment, and particularly relates to a type-B leakage protection circuit breaker, which is applicable to detecting leakage in an AC power supply system and cutting off the power line. Background Art

[0002] The residual current protection technology is widely applied in low-voltage power grids to prevent electric shock, electrical fires, personal injuries and electrical equipment damage accidents caused by grounding faults. The existing leakage protection circuit breakers are mainly divided into type-A and type-B. The type-A leakage protection circuit breaker can only detect AC leakage current, while the type-B leakage protection circuit breaker can not only detect AC leakage current, but also detect DC leakage current, and is particularly applicable to power supply equipment containing DC components, such as frequency converters, electric vehicle charging piles, etc.

[0003] With the development of smart grids and the continuous increase of electrical equipment, the types of electrical equipment are also diversified. When a device fails, the generated residual current is no longer a single power frequency sine current, but a current with pulsating DC components or even smooth DC components. In some cases, the frequency of the residual current signal is as high as 1000 Hz or even higher. This requires the leakage protection circuit breaker to accurately and reliably detect complex leakage current, have high detection accuracy, high sensitivity and response speed, and reduce misoperation. Content of the Utility Model

[0004] To overcome the deficiencies of the prior art, the technical problem to be solved by the utility model is to provide a type-B leakage protection circuit breaker.

[0005] The utility model adopts the following technical solutions to solve the above technical problems:

[0006] A type-B leakage protection circuit breaker includes a main control module, a signal acquisition module, a signal processing module, a power supply module and a tripping module; the signal acquisition module includes a leakage current transformer, and the toroidal core of the leakage current transformer passes through the live wire and the neutral wire of the power line to sense the leakage current and couple the leakage current into the exciting current; the signal processing module includes operational amplifiers U1B, U2A, U2B, U2C, U3A and U3B; the operational amplifier U1B is used to solve the problem of distortion of the exciting voltage signal, and the operational amplifiers U2A, U2B and U2C form a three-stage low-pass filter to filter out the high-frequency components in the exciting voltage signal to obtain a leakage voltage signal; the leakage voltage signal is raised to a magnitude that can be detected by the A / D converter of the main control module through the operational amplifiers U3A and U3B.

[0007] Further, the signal acquisition module further includes a first resistor to a seventh resistor, a transient suppression diode, an operational amplifier U1A, a first capacitor to a third capacitor, a first triode, and a second triode; one end of the first resistor is connected in series with the fourth resistor, the other end of the first resistor is grounded, and the other end of the fourth resistor is connected to the inverting input terminal of the operational amplifier U1A; one end of the second resistor is connected in series with the fifth resistor, the other end of the second resistor is grounded, and the other end of the fifth resistor is connected to the inverting input terminal of the operational amplifier U1A; one end of the third resistor is grounded, and the other end is connected to the non-inverting input terminal of the operational amplifier U1A and one end of the sixth resistor, and the other end of the sixth resistor is connected to the output terminal of the operational amplifier U1A; after the seventh resistor is connected in parallel with the third capacitor, one end is connected to the output terminal of the operational amplifier U1A, and the other end is connected to the bases of the first triode and the second triode. The emitters of the first triode and the second triode are commonly connected. The collector of the first triode is connected to the positive pole of the voltage source, and the collector of the second triode is connected to the negative pole of the voltage source; the leakage current transformer is connected in parallel with the transient suppression diode, one end is connected to the inverting input terminal of the operational amplifier U1A, and the other end is commonly connected to the emitters of the first triode and the second triode; one end of the first capacitor is connected to the positive power supply terminal of the operational amplifier U1A, and the other end is grounded; one end of the second capacitor is connected to the negative power supply terminal of the operational amplifier U1A, and the other end is grounded.

[0008] Further, the signal processing module further includes the eighth resistor to the thirty-first resistor, the resistor RT1 to the resistor RT4, and the fourth capacitor to the eleventh capacitor; the non-inverting input terminal of the operational amplifier U1B is simultaneously connected to one end of the first resistor, the fourth resistor, the second resistor, and the fifth resistor, the inverting input terminal of the operational amplifier U1B is connected to the output terminal, the output terminal of the operational amplifier U1B is simultaneously connected to one end of the eighth resistor, the other end of the eighth resistor is connected to one end of the ninth resistor and the fourth capacitor, the other end of the fourth capacitor is grounded, the other end of the ninth resistor is connected to one end of the fifth capacitor and the tenth resistor, the other end of the fifth capacitor is grounded, and the other end of the tenth resistor is connected to the inverting input terminal of the operational amplifier U2A; the eleventh resistor and the thirteenth resistor are connected in series and then one end is connected to one end of the tenth resistor and the other end of the ninth resistor, and the other end is connected to the output terminal of the operational amplifier U2A; the sixth capacitor is connected in parallel between the inverting input terminal and the output terminal of the operational amplifier U2A, one end of the twelfth resistor is connected to the non-inverting input terminal of the operational amplifier U2A, and the other end is grounded; one end of the sixteenth resistor is connected to the output terminal of the operational amplifier U2A, and the other end is connected to the inverting input terminal of the operational amplifier U2B; the resistor RT1 and the resistor RT2 are connected in series and then connected in parallel with the eighth capacitor, and one end of the parallel circuit is connected to the inverting input terminal of the operational amplifier U2B, and the other end is connected to the output terminal of the operational amplifier U2B; the non-inverting input terminal of the operational amplifier U2B leads out a wire and is connected to one end of the seventh capacitor and the nineteenth resistor, the other end of the seventh capacitor is grounded, and the other end of the nineteenth resistor is simultaneously connected to one end of the seventeenth resistor and the eighteenth resistor, the other end of the seventeenth resistor is connected to the power supply through the fourteenth resistor, and the other end of the eighteenth resistor is connected to the negative pole of the voltage source through the fifteenth resistor; the twentieth resistor and the twenty-first resistor are connected in series, one end is connected to the output terminal of the operational amplifier U2B, and the other end is connected to the inverting input terminal of the operational amplifier U2C; the resistor RT3 and the resistor RT4 are connected in series and then connected in parallel with the ninth capacitor, and one end of the parallel circuit is connected to the inverting input terminal of the operational amplifier U2C, and the other end is connected to the output terminal of the operational amplifier U2C, and the non-inverting input terminal of the operational amplifier U2C is grounded; one end of the twenty-fourth resistor is connected to the output terminal of the operational amplifier U2C, and the other end is simultaneously connected to one end of the twenty-fifth resistor and the inverting input terminal of the operational amplifier U3A, the other end of the twenty-fifth resistor is connected to the output terminal of the operational amplifier U3A, the output terminal of the operational amplifier U3A is simultaneously connected to one end of the twenty-sixth resistor, and the other end of the twenty-sixth resistor is connected to the main control module; one end of the twenty-second resistor and the twenty-third resistor is simultaneously connected to the non-inverting input terminal of the operational amplifier U3A, and the other end of the twenty-third resistor is grounded; the non-inverting input terminal of the operational amplifier U3B is simultaneously connected to one end of the twenty-seventh resistor and the twenty-eighth resistor, the other end of the twenty-seventh resistor inputs the working voltage, and the other end of the twenty-eighth resistor is grounded;The inverting input terminal of operational amplifier U3B is connected to one end of the twenty-ninth resistor, the thirtieth resistor, and the tenth capacitor. The other end of the twenty-ninth resistor is grounded. The other end of the thirtieth resistor is connected to the other end of the twenty-second resistor. The other end of the tenth capacitor is connected to the output terminal of operational amplifier U3B. The output terminal of operational amplifier U3B is simultaneously connected to one end of the thirty-first resistor. The other end of the thirty-first resistor is connected to the other end of the twenty-second resistor. One end of the eleventh capacitor is connected to the operating voltage input terminal of operational amplifier U3B, and the other end is grounded.

[0009] Further, the tripping module includes a rectifier bridge, the thirty-second resistor to the thirty-fourth resistor, the twelfth capacitor, an inductor, a diode, a thyristor, and a varistor. One end of the thirty-second resistor and the varistor is connected to the live wire of the power line. The other end of the thirty-second resistor is connected to the 4th pin of the rectifier bridge. The other end of the varistor and the 2nd pin of the rectifier bridge are simultaneously connected to the neutral wire of the power line. The 1st pin of the rectifier bridge is connected to one end of the inductor and the diode. The other ends of the inductor and the diode lead out wires and are simultaneously connected to one end of the thirty-third resistor and the A pin of the thyristor. The other end of the thirty-third resistor is connected to the power module. The G pin of the thyristor is connected to one end of the thirty-fourth resistor and the twelfth capacitor. The K pin is connected to the other ends of the thirty-fourth resistor and the twelfth capacitor and is connected to the 3rd pin of the rectifier bridge and grounded.

[0010] Compared with the prior art, the beneficial effects of the present utility model are:

[0011] 1. The signal acquisition module is based on the voltage-type magnetic modulation principle, couples the leakage current into the exciting current, and realizes the detection of complex leakage current by detecting the exciting current. This method overcomes the defects of traditional magnetic modulation type current detection and improves the accuracy and reliability of detection. Since the waveform of the signal output by the leakage current transformer is very complex and contains many high-frequency components with interference, it is required that the attenuation rate of the filter is as fast as possible. Therefore, the signal processing module adopts a multi-stage Butterworth low-pass filter to filter out the high-frequency components in the exciting current and retain the low-frequency components reflecting the leakage current, which can reduce the requirements for the A / D converter and the microprocessor, thereby reducing the complexity and cost of the hardware circuit. The characteristics of the Butterworth low-pass filter are between those of the Chebyshev low-pass filter and the Bessel low-pass filter, that is, it has good transient response characteristics and amplitude response characteristics, and is the flattest in the passband. At the same time, considering that the leakage current signal belongs to a weak current signal in the milliampere level, the passband ripple of the filter should be as small as possible to avoid affecting signal demodulation. Considering comprehensively, the Butterworth analog low-pass filter with the best performance is selected for signal processing.

[0012] 2. The leakage current transformer has good temperature stability and low zero drift, and is not easily affected by external magnetic fields. Therefore, this leakage protector can maintain stable detection performance during long-term use and is suitable for various complex electromagnetic environments.

[0013] 3. The utility model can realize real-time monitoring and information collection of leakage current, including alternating current leakage current, direct current leakage current, and power supply equipment containing direct current components, and can accurately judge the leakage situation. When the detected leakage current exceeds the safety threshold, the protector quickly cuts off the power line, with a faster response speed and a lower probability of misoperation, preventing electric shock accidents and ensuring the safety and reliability of the power consumption environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the overall control block diagram of the utility model;

[0015] Figure 2 is the circuit diagram of the signal acquisition module of the utility model;

[0016] Figure 3 is a part of the circuit diagram of the signal processing module of the utility model;

[0017] Figure 4 is another part of the circuit diagram of the signal processing module of the utility model;

[0018] Figure 5 is the circuit diagram of the tripping module of the utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following provides specific embodiments in conjunction with the drawings. The specific embodiments are only used to introduce the technical solutions of the utility model in detail and are not used to limit the protection scope of this application.

[0020] The utility model is a type B leakage protection circuit breaker, including a main control module, a signal acquisition module, a signal processing module, a power supply module, and a tripping module; the power supply module supplies power to the main control module, the signal acquisition module, and the signal processing module at the same time. The signal acquisition module collects the exciting current and converts it into a voltage signal. The signal processing module filters the exciting current to remove its high-frequency components and retains the low-frequency components mainly reflecting the leakage current of the power line. At the same time, the leakage current signal is converted into a voltage signal. The main control module controls the tripping module to act according to the magnitude of the leakage voltage. When the leakage voltage is greater than the set threshold, the tripping module is driven to perform a tripping action to cut off the live wire or neutral wire of the power line.

[0021] The signal acquisition module includes a first resistor R1 to a seventh resistor R7, a leakage current transformer LH1, a transient voltage suppression diode TVS1, an operational amplifier U1A, a first capacitor C1 to a third capacitor C3, a first triode Q1, and a second triode Q2;

[0022] The first resistor R1 and the fourth resistor R4 are connected in series. The other end of the first resistor R1 is grounded, and the other end of the fourth resistor R4 is connected to the inverting input terminal of the operational amplifier U1A; the second resistor R2 and the fifth resistor R5 are connected in series. The other end of the second resistor R2 is grounded, and the other end of the fifth resistor R5 is connected to the inverting input terminal of the operational amplifier U1A; one end of the third resistor R3 is grounded, and the other end is respectively connected to the non-inverting input terminal of the operational amplifier U1A and one end of the sixth resistor R6. The other end of the sixth resistor R6 is connected to the output terminal of the operational amplifier U1A; after the seventh resistor R7 is connected in parallel with the third capacitor, one end is connected to the output terminal of the operational amplifier U1A, and the other end is respectively connected to the base of the first triode Q1 and the base of the second triode Q2. The emitters of the first triode Q1 and the second triode Q2 are connected together. The collector of the first triode Q1 is connected to the positive pole VCC of the voltage source, and the collector of the second triode Q2 is connected to the negative pole VEE of the voltage source; after the leakage current transformer LH1 is connected in parallel with the transient suppression diode TVS1, one end is connected to the inverting input terminal of the operational amplifier U1A, and the other end is connected to the common connection of the emitters of the first triode Q1 and the second triode Q2. The toroidal core of the leakage current transformer LH1 passes through the live wire L and the neutral wire N of the power line at the same time; one end of the first capacitor C1 is connected to the positive power supply terminal of the operational amplifier U1A, and the other end is grounded; one end of the second capacitor C2 is connected to the negative power supply terminal of the operational amplifier U1A, and the other end is grounded. Among them, the square wave voltage output by the operational amplifier U1A is used as the excitation voltage source of the leakage current transformer LH1. Specifically, the fourth resistor R4 and the fifth resistor R5 are used as sampling resistors. When the voltage on the sampling resistor reaches the preset threshold voltage (the threshold voltage is set by the third resistor R3 and the sixth resistor R6), the polarity of the output voltage of the operational amplifier U1A will reverse, so that an excitation voltage is automatically generated on the leakage current transformer LH1. This excitation voltage is used to drive the toroidal core of the leakage current transformer LH1 to generate an alternating magnetic field. Since the toroidal core passes through the live wire L and the neutral wire N of the power line, the toroidal core can sense the leakage current of the live wire L and the neutral wire N. The collected leakage current is coupled into the excitation current through the leakage current transformer LH1, and then the excitation current signal is converted into an excitation voltage signal by the sampling resistor to realize the detection of the leakage current.

[0023] The signal processing module includes operational amplifiers U1B, U2A, U2B, U2C, U3A, U3B, the eighth resistor R8 to the thirty-first resistor R31, the resistors RT1 to RT4, and the fourth capacitor C4 to the eleventh capacitor C11;

[0024] The non-inverting input terminal of operational amplifier U1B is connected to one end of resistor R1, resistor R4, resistor R2, and resistor R5 simultaneously. The inverting input terminal of operational amplifier U1B is connected to its output terminal. The output terminal of operational amplifier U1B is connected to one end of resistor R8. The other end of resistor R8 leads out a wire and is connected to one end of resistor R9 and capacitor C4. The other end of capacitor C4 is grounded. The other end of resistor R9 is connected to one end of capacitor C5 and resistor R10. The other end of capacitor C5 is grounded. The other end of resistor R10 is connected to the inverting input terminal of operational amplifier U2A. Resistor R11 and resistor R13 are connected in series, and one end of the series connection is connected to one end of resistor R10 and the other end of resistor R9, and the other end is connected to the output terminal of operational amplifier U2A. Capacitor C6 is connected in parallel between the inverting input terminal and the output terminal of operational amplifier U2A. One end of resistor R12 is connected to the non-inverting input terminal of operational amplifier U2A, and the other end is grounded. One end of resistor R16 is connected to the output terminal of operational amplifier U2A, and the other end is connected to the inverting input terminal of operational amplifier U2B. Resistor RT1 and resistor RT2 are connected in series and then connected in parallel with capacitor C8. One end of the parallel circuit is connected to the inverting input terminal of operational amplifier U2B, and the other end is connected to the output terminal of operational amplifier U2B. The non-inverting input terminal of operational amplifier U2B leads out a wire and is connected to one end of capacitor C7 and resistor R19. The other end of capacitor C7 is grounded. The other end of resistor R19 is connected to one end of resistor R17 and resistor R18 simultaneously. The other end of resistor R17 is connected to the power supply through resistor R14. The other end of resistor R18 is connected to the negative pole VEE of the voltage source through resistor R15. Resistor R20 and resistor R21 are connected in series, and one end of the series connection is connected to the output terminal of operational amplifier U2B, and the other end is connected to the inverting input terminal of operational amplifier U2C. Resistor RT3 and resistor RT4 are connected in series and then connected in parallel with capacitor C9. One end of the parallel circuit is connected to the inverting input terminal of operational amplifier U2C, and the other end is connected to the output terminal of operational amplifier U2C. The non-inverting input terminal of operational amplifier U2C is grounded. One end of resistor R24 is connected to the output terminal of operational amplifier U2C, and the other end is connected to one end of resistor R25 and the inverting input terminal of operational amplifier U3A simultaneously. The other end of resistor R25 is connected to the output terminal of operational amplifier U3A. The output terminal of operational amplifier U3A is connected to one end of resistor R26 simultaneously. The other end of resistor R26 is connected to the main control module. One end of resistor R22 and resistor R23 is connected to the non-inverting input terminal of operational amplifier U3A simultaneously. The other end of resistor R23 is grounded.The non-inverting input terminal of operational amplifier U3B is connected to one end of the 27th resistor R27 and the 28th resistor R28 at the same time. The other end of the 27th resistor R27 inputs the working voltage, and the other end of the 28th resistor R28 is grounded. The inverting input terminal of operational amplifier U3B is connected to one end of the 29th resistor R29, the 30th resistor R30, and the 10th capacitor C10. The other end of the 29th resistor R29 is grounded. The other end of the 30th resistor R30 is connected to the other end of the 22nd resistor R22. The other end of the 10th capacitor C10 is connected to the output terminal of operational amplifier U3B. The output terminal of operational amplifier U3B is connected to one end of the 31st resistor R31 at the same time. The other end of the 31st resistor R31 is connected to the other end of the 22nd resistor R22. One end of the 11th capacitor C11 is connected to the working voltage input terminal of operational amplifier U3B, and the other end is grounded. Each operational amplifier of the signal processing module forms a multi-stage Butterworth low-pass filter, the purpose of which is to filter out the high-frequency components of the excitation voltage and obtain its low-frequency components. The excitation voltage signal collected by the signal acquisition module is processed by operational amplifier U1B, which solves the problem of signal distortion caused by insufficient driving ability of the signal acquisition module. The excitation voltage signal processed by operational amplifier U1B is then filtered by a three-stage low-pass filter composed of operational amplifiers U2A to U2C to filter out the high-frequency components and retain the detectable leakage voltage signal. Then, the leakage voltage signal is raised to a magnitude that can be detected by the A / D converter of the main control module through operational amplifiers U3A and U3B.;

[0025] The tripping module includes a rectifier bridge M1, the 32nd resistor R32 to the 34th resistor R34, the 12th capacitor C12, an inductor L1, a diode D1, a thyristor S1, and a varistor RV1. One end of the 32nd resistor R32 and the varistor RV1 is connected to the live wire L of the power line. The other end of the 32nd resistor R32 is connected to the 4th pin of the rectifier bridge M1. The other end of the varistor RV1 and the 2nd pin of the rectifier bridge M1 are connected to the neutral wire N of the power line at the same time. The 1st pin of the rectifier bridge M1 is connected to one end of the inductor L1 and the diode D1. The other ends of the inductor L1 and the diode D1 lead out wires and are connected to one end of the 33rd resistor R33 and the A pin of the thyristor S1 at the same time. The other end of the 33rd resistor R33 is connected to the power supply module. The G pin of the thyristor S1 is connected to one end of the 34th resistor R34 and the 12th capacitor C12. The K pin is connected to the other end of the 34th resistor R34 and the 12th capacitor C12 and is connected to the 3rd pin of the rectifier bridge M1 and is grounded.

[0026] The main control module uses the STM8L051F3 chip. The STM8L051F3 chip is connected to the signal processing module through the AD acquisition interface and is used to monitor whether the magnitude of the leakage voltage is normal. The PB1 pin and PB2 pin of the STM8L051F3 chip are the zero point and the 24 mA leakage calibration point respectively. PD0 is connected to the leakage indicator light, which will flash to prompt when leakage occurs and the switch is closed. The STM8L051F3 chip is connected to the tripping action module through the PC4 pin to perform leakage tripping.

[0027] The working principle and working process of the present utility model are as follows:

[0028] The leakage current collected by the leakage current transformer of the signal acquisition module is coupled into the exciting current. This process is realized through the principle of electromagnetic induction, and the change of the leakage current is converted into an exciting current proportional to it. Subsequently, the exciting current is processed by the multi-stage Butterworth low-pass filters of the signal processing module. These filters effectively filter out high-frequency interference signals, retain the low-frequency leakage current signal, and at the same time convert the leakage current signal into a voltage signal. The leakage voltage signal is transmitted to the main control module, and the main control module converts the leakage voltage signal from an analog signal into a digital signal. When the magnitude of the leakage voltage reaches the preset threshold, the main control module issues a tripping signal and drives the tripping action to perform the tripping action, disconnecting the circuit electronically, thereby disconnecting the power supply of the live wire or neutral wire to the load, achieving the purpose of protecting the circuit and equipment. The whole process ensures that in case of leakage or other abnormal current conditions, the circuit can respond quickly, cut off the power supply in time, and prevent potential safety hazards. In this way, real-time monitoring and protection of the circuit can be realized to ensure electrical safety.

[0029] Matters not described in the present utility model are applicable to the prior art.

Claims

1. A B-type leakage protection circuit breaker, comprising a main control module, a signal acquisition module, a signal processing module, a power module and a trip module; characterized in that: The signal acquisition module includes a leakage transformer, the annular magnetic core of which passes through the live wire and the neutral wire of the power line to sense the leakage current and couple the leakage current into the excitation current; The signal processing module includes an operational amplifier U1B, an operational amplifier U2A, an operational amplifier U2B, an operational amplifier U2C, an operational amplifier U3A and an operational amplifier U3B; the operational amplifier U1B is used to solve the problem of distortion of the excitation voltage signal, and the operational amplifiers U2A, U2B and U2C form a three-stage low-pass filter to filter out the high-frequency components in the excitation voltage signal to obtain a leakage voltage signal; the leakage voltage signal is raised to a level that can be detected by the A / D converter of the main control module through the operational amplifiers U3A and U3B; The signal acquisition module also includes resistors No. 1 to No. 7, a transient suppression diode, an operational amplifier U1A, capacitors No. 1 to No. 3, a transistor No. 1 and a transistor No. 2; one end of the resistor No. 1 is connected in series with the resistor No. 4, the other end of the resistor No. 1 is grounded, and the other end of the resistor No. 4 is connected to the inverting input terminal of the operational amplifier U1A; one end of the resistor No. 2 is connected in series with the resistor No. 5, the other end of the resistor No. 2 is connected to the ground, and the other end of the resistor No. 5 is connected to the inverting input terminal of the operational amplifier U1A; one end of the resistor No. 3 is grounded, and the other end is connected to the non-inverting input terminal of the operational amplifier U1A and one end of the resistor No. 6, and the other end of the resistor No. 6 is connected to the output terminal of the operational amplifier U1A; After resistor No. 7 is connected in parallel with capacitor No. 3, one end of the resistor is connected to the output end of operational amplifier U1A, and the other end is connected to the base of transistor No. 1 and the base of transistor No. 2, the emitters of transistor No. 1 and transistor No. 2 are connected in common, the collector of transistor No. 1 is connected to the positive electrode of the voltage source, and the collector of transistor No. 2 is connected to the negative electrode of the voltage source; after the leakage transformer is connected in parallel with the transient suppression diode, one end is connected to the inverting input end of operational amplifier U1A, and the other end is connected in common with the emitters of transistor No. 1 and transistor No. 2; one end of capacitor No. 1 is connected to the positive power supply end of operational amplifier U1A, and the other end is grounded; one end of capacitor No. 2 is connected to the negative power supply end of operational amplifier U1A, and the other end is grounded.

2. A B-type leakage protection circuit breaker according to claim 1, characterized in that: The signal processing module also includes resistors No. 8 to No. 31, resistors RT1 to RT4, and capacitors No. 4 to No. 11; the non-inverting input terminal of the operational amplifier U1B is simultaneously connected to resistor No. 1, resistor No. 4, one end of resistor No. 2, and one end of resistor No. 5, the inverting input terminal of the operational amplifier U1B is connected to the output terminal, the output terminal of the operational amplifier U1B is simultaneously connected to one end of resistor No. 8, the other end of resistor No. 8 is connected to one end of resistor No. 9 and capacitor No. 4, the other end of capacitor No. 4 is grounded, the other end of resistor No. 9 is connected to one end of capacitor No. 5 and resistor No. 10, the other end of capacitor No. 5 is grounded, and the other end of resistor No. 10 is connected to the inverting input terminal of the operational amplifier U2A; resistor No. 11 is connected to resistor No. 13 After the resistors are connected in series, one end is connected to one end of resistor No. 10 and the other end of resistor No. 9, and the other end is connected to the output end of operational amplifier U2A; capacitor No. 6 is connected in parallel between the inverting input and output ends of operational amplifier U2A, one end of resistor No. 12 is connected to the non-inverting input end of operational amplifier U2A, and the other end is grounded; one end of resistor No. 16 is connected to the output end of operational amplifier U2A, and the other end is connected to the inverting input end of operational amplifier U2B; resistor RT1 and resistor RT2 are connected in series and then connected in parallel with capacitor No. 8, and one end of the circuit after parallel connection is connected to the inverting input end of operational amplifier U2B, and the other end is connected to the output end of operational amplifier U2B; a lead wire from the non-inverting input end of operational amplifier U2B is connected to capacitor No. 7 and one end of resistor No. 19, the other end of capacitor No. 7 is grounded, the other end of resistor No. 19 is connected to one end of resistor No. 17 and resistor No. 18 at the same time, the other end of resistor No. 17 is connected to the power supply through resistor No. 14, and the other end of resistor No. 18 is connected to the negative electrode of the voltage source through resistor No. 15; after resistor No. 20 is connected in series with resistor No. 21, one end is connected to the output end of operational amplifier U2B, and the other end is connected to the inverting input end of operational amplifier U2C; resistor RT3 and resistor RT4 are connected in series and then connected in parallel with capacitor No. 9, one end of the parallel circuit is connected to the inverting input end of operational amplifier U2C, and the other end is connected to the output end of operational amplifier U2C, and the non-inverting input end of operational amplifier U2C is grounded; One end of resistor No. 4 is connected to the output end of operational amplifier U2C, and the other end is connected to one end of resistor No. 25 and the inverting input end of operational amplifier U3A at the same time. The other end of resistor No. 25 is connected to the output end of operational amplifier U3A. The output end of operational amplifier U3A is connected to one end of resistor No. 26 at the same time. The other end of resistor No. 26 is connected to the main control module; one end of resistor No. 22 and resistor No. 23 are connected to the positive phase input end of operational amplifier U3A at the same time, and the other end of resistor No. 23 is grounded; the positive phase input end of operational amplifier U3B is connected to one end of resistor No. 27 and resistor No. 28 at the same time. The other end of resistor No. 27 inputs the working voltage, and the other end of resistor No. 28 is grounded;The inverting input terminal of the operational amplifier U3B is connected to the No. 29 resistor, the No. 30 resistor and one end of the No. 10 capacitor. The other end of the No. 29 resistor is grounded. The other end of the No. 30 resistor is connected to the other end of the No. 22 resistor. The other end of the No. 10 capacitor is connected to the output terminal of the operational amplifier U3B. The output terminal of the operational amplifier U3B is also connected to one end of the No. 31 resistor. The other end of the No. 31 resistor is connected to the other end of the No. 22 resistor. One end of the No. 11 capacitor is connected to the working voltage input terminal of the operational amplifier U3B, and the other end is grounded. ; 3. A B-type leakage protection circuit breaker according to claim 1, characterized in that: The tripping module includes a rectifier bridge, resistors No. 32 to No. 34, capacitor No. 12, an inductor, a diode, a thyristor and a varistor; one end of the resistor No. 32 and the varistor is connected to the live wire of the power supply circuit, the other end of the resistor No. 32 is connected to pin No. 4 of the rectifier bridge, and the other end of the varistor is connected to pin No. 2 of the rectifier bridge and the neutral wire of the power supply circuit; pin No. 1 of the rectifier bridge is connected to one end of the inductor and the diode, and the other end of the inductor and the diode leads out a wire and is connected to one end of the resistor No. 33 and pin A of the thyristor at the same time, the other end of the resistor No. 33 is connected to the power module, the G pin of the thyristor is connected to one end of the resistor No. 34 and capacitor No. 12, the K pin is connected to the other end of the resistor No. 34 and capacitor No. 12 and is connected to pin No. 3 of the rectifier bridge and grounded.