Resistance-capacitance voltage reduction device temperature rise control circuit capable of resisting higher harmonics

Abstract

The invention provides an anti-higher harmonic resistance-capacitance step-down device temperature rise control circuit. The circuit comprises an EMC circuit, a resistance-capacitance step-down loop, a rectification circuit, a TVS leakage current bypass discharge circuit, a TVS voltage stabilization and leakage current sampling circuit and a DC / DC BUCK step-down circuit which are connected in sequence. By introducing the TVS leakage current bypass discharge circuit and the TVS leakage current sampling circuit, the problem of overhigh temperature rise caused by large leakage current under harmonic waves of a TVS voltage-regulator tube in a traditional resistance-capacitance voltage reduction scheme is effectively solved, and the long-term operation reliability of the intelligent electric meter is remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power electronics, and relates to a low-power resistance-capacitance voltage reduction scheme for the field of smart grids, aiming to solve the problem of excessively high temperature rise of a TVS voltage stabilizing tube caused by on-site harmonics and improve the reliability of long-term operation of a smart meter. BACKGROUND

[0002] In the field of smart grids, a low-power resistance-capacitance voltage reduction scheme is usually used as a power supply scheme for low-end meters. The resistance-capacitance voltage reduction scheme is widely used due to its low cost, simple structure and no need for complex transformer design. However, the traditional resistance-capacitance voltage reduction scheme has some inherent defects in actual application, especially in a harsh harmonic operating environment, the TVS voltage stabilizing tube is prone to excessively high temperature rise due to excessive leakage current, which causes device failure during long-term operation, resulting in a black screen of the meter and affecting the reliability and service life of the system.

[0003] The existing solutions usually increase the heat dissipation area of the TVS tube or select a higher-power TVS tube to alleviate the temperature rise problem, but these methods increase the system cost and volume, and have limited effect, often failing to effectively control the temperature rise of the TVS tube, resulting in a decrease in system stability and even causing failure.

[0004] Therefore, there is an urgent need for a circuit design that can effectively control the temperature rise of the TVS to solve the above problems. SUMMARY

[0005] The purpose of the application is to solve the problem of excessively high temperature rise of a TVS voltage stabilizing tube caused by on-site harmonics, and to propose a resistance-capacitance voltage reduction device temperature rise control circuit resistant to high-order harmonics, which improves the long-term operation reliability of a smart meter by introducing a TVS leakage current bypass discharge circuit and a TVS leakage current sampling circuit.

[0006] The technical scheme of the application is: The application provides a resistance-capacitance voltage reduction device temperature rise control circuit resistant to high-order harmonics, comprising an EMC circuit, a resistance-capacitance voltage reduction loop, a rectifier circuit, a TVS leakage current bypass discharge circuit, a TVS voltage stabilization and leakage current sampling circuit, and a DC / DC BUCK voltage reduction circuit connected in sequence. The EMC circuit is used to obtain a three-phase four-wire input power supply signal, perform harmonic suppression and interference filtering, and obtain a filtered alternating current signal. The resistance-capacitance voltage reduction loop is used to reduce the voltage of the filtered alternating current signal and obtain a reduced alternating current signal. The rectifier circuit is a full-bridge circuit composed of rectifier diodes, which is used to convert the reduced alternating current signal into a direct current signal. The TVS leakage current bypass discharge circuit is used to receive the control signal Discharge from the microcontroller and dynamically adjust the on / off state of the transistor control circuit according to the leakage current sampling value to bypass the TVS leakage current. The TVS voltage regulator and leakage current sampling circuit is used to regulate the DC signal and sample the leakage current, and the TVS leakage current sampling value is used as the OCP sampling signal to be output to the controller. A DC / DC buck converter is used to step down a regulated DC signal and output the target voltage to the load.

[0007] Furthermore, the RC step-down circuit includes capacitors C1-C3 and resistors R6-R8. Capacitor C1 is connected in parallel with resistor R6, capacitor C2 is connected in parallel with resistor R7, and capacitor C3 is connected in parallel with resistor R8. One end of capacitors C1, C2, and C3 is connected to the A, B, and C phase output terminals of the EMC circuit, respectively, and the other end of capacitors C1, C2, and C3 is connected to the input terminal of the rectifier circuit, respectively. The N phase output terminal of the EMC circuit is connected to the input terminal of the rectifier circuit.

[0008] Furthermore, the TVS voltage regulator and leakage current sampling circuit includes a TVS diode D2, resistors R4 and R5, and capacitor C5; The output terminal of the rectifier circuit is connected to the positive terminal of diode D1, and the negative terminal of diode D1 is connected to the positive terminal of capacitor C4 and the input terminal of the TVS voltage regulator and leakage current sampling circuit. The negative terminal of capacitor C4 is grounded. The capacitor C4 is used for energy storage and filtering, and the diode D1 is used to realize the reverse power failure prevention function. That is, when the circuit is powered off, if the TVS leakage current bypass discharge circuit fails to turn off in time, it can prevent the energy stored in capacitor C4 from flowing back into the discharge circuit. The negative terminal of the TVS diode D2 is connected to the negative terminal of the diode D1 as the input terminal of the TVS voltage regulation and leakage current sampling circuit. The positive terminal of the TVS diode D2 is connected to one end of the resistors R4 and R5. The other end of the resistor R5 is connected to one end of the capacitor C5 and serves as the output of the TVS voltage regulation and leakage current sampling circuit, generating an OCP sampling signal that is connected to the corresponding input terminal of the controller. The other end of the capacitor C5 and the other end of the resistor R4 are grounded.

[0009] Furthermore, the TVS leakage current bypass discharge circuit is a single-channel or multi-channel structure; When it is a single-channel structure, a single discharge circuit includes a discharge resistor R1 and a transistor control circuit consisting of a transistor Q1, resistors R2 and R3. One end of the discharge resistor R1 is connected to the output terminal of the rectifier circuit, and the other end is connected to the collector of the transistor Q1. The base of the transistor Q1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the control signal output terminal of the microcontroller. The connection point between the resistor R2 and the base of the transistor Q1 is connected to one end of the resistor R3, and the other end of the resistor R3 is grounded.

[0010] Furthermore, the TVS leakage current bypass discharge circuit is a single-channel or multi-channel structure; When it is a multi-path structure, it includes n parallel discharge branches, n≥2; each discharge branch is composed of an independent discharge resistor and a transistor control circuit; the transistor control circuit is controlled hierarchically by the controller’s n-level threshold voltage comparison logic, so that different discharge branches are activated in a time-sharing manner according to the TVS leakage current sampling value.

[0011] Furthermore, the n-level threshold voltage comparison logic is set with n thresholds, from low to high, namely the first threshold to the nth threshold, which are matched with the corresponding parallel discharge branch; When the TVS leakage current sampling value is lower than the first threshold, all discharge branches are turned off; When the TVS leakage current sampling value is between the first threshold and the second threshold, the first discharge branch is turned on. Similarly, when the TVS leakage current sampling value is between the (n-1)th threshold and the nth threshold, the first to (n-1)th discharge branches are turned on. When the TVS leakage current sampling value is greater than the nth threshold, all discharge branches are turned on.

[0012] Furthermore, in the multi-level threshold voltage comparison logic of the controller, the shutdown time of the discharge branch does not exceed 200ms, so as to ensure that the system can quickly release its load-carrying capacity when the TVS leakage current decreases.

[0013] Furthermore, the TVS voltage regulation and leakage current sampling circuit includes a resistor R4, an RC filter circuit composed of a resistor R5 and a capacitor C5, and a TVS voltage regulator D2. The negative terminal of the TVS voltage regulator D2 is connected to the negative terminal of the diode D1, and the positive terminal of the TVS voltage regulator D2 is connected to one end of the resistor R4. The resistor R4 is the TVS leakage current sampling resistor, used to convert the TVS leakage current into a voltage signal. The other end of the resistor R4 is grounded. The resistor R5 and the capacitor C5 form an RC filter circuit, used to filter out glitches in the voltage sampling signal. The connection point of the resistor R5 and the capacitor C5 serves as the output of the TVS voltage regulation and leakage current sampling circuit, outputting an OCP sampling signal to the controller.

[0014] Furthermore, the input terminal of the DC / DC BUCK step-down circuit is connected to the output terminal of the TVS voltage regulator and leakage current sampling circuit, the output terminal of the DC / DC BUCK step-down circuit is connected to the system load, and one end of the filter capacitor C6 is connected to it, while the other end of the capacitor C6 is grounded.

[0015] Furthermore, the microcontroller executes the following control steps to dynamically adjust the on / off state of the bypass discharge circuit, including: S1. Power-on initialization: Configure the control signal of the transistor control circuit in the TVS leakage current bypass discharge circuit to a low level, and turn off the TVS leakage current bypass discharge circuit. S2. Interrupt handling: When the timer is interrupted, the ADC sampling function is called to obtain the TVS leakage current sampling value, i.e., the OCP sampling signal, in real time. The TVS leakage current sampling value is compared with a preset threshold. The control signal level is adjusted according to the comparison result to dynamically control the on / off state of the discharge branch.

[0016] If the TVS leakage current bypass discharge circuit is a single-channel structure, the discharge branch will be activated when the TVS leakage current sampling value is higher than the single-channel threshold. If the TVS leakage current bypass discharge circuit is a multi-channel structure, it adopts n-level threshold voltage comparison logic, from low to high, which are the first threshold to the nth threshold, and are matched with the corresponding parallel discharge branch. When the TVS leakage current sampling value is lower than the first threshold, all discharge branches are turned off; When the TVS leakage current sampling value is between the first threshold and the second threshold, the first discharge branch is turned on. Similarly, when the TVS leakage current sampling value is between the (n-1)th threshold and the nth threshold, the first to (n-1)th discharge branches are turned on. When the TVS leakage current sampling value is greater than the nth threshold, all discharge branches are turned on.

[0017] The beneficial effects of this invention are: This invention discloses a temperature rise control circuit for RC step-down devices that resists high-order harmonics. It addresses the problem in traditional RC step-down circuits where excessive leakage current in the TVS diode leads to excessive temperature rise, affecting device lifespan and system stability. On the hardware side, it employs an EMC circuit, an RC step-down loop, a rectifier circuit, a TVS voltage regulator and leakage current sampling circuit, a TVS leakage current bypass discharge circuit, and a DC / DC BUCK step-down circuit to construct a highly efficient temperature rise control system. The introduction of the TVS leakage current bypass discharge circuit, through a discharge resistor and a transistor control circuit, bypasses part of the TVS leakage current, significantly reducing the TVS diode's temperature rise. Simultaneously, the TVS voltage regulator and leakage current sampling circuit samples the TVS leakage current in real time, providing data support for microcontroller control.

[0018] This invention uses a TVS leakage current sampling circuit to sample the TVS leakage current in real time, converting it into a voltage signal. After RC filtering, this signal provides real-time data for the software control logic. Combined with multi-level threshold voltage comparison logic, it dynamically adjusts the on / off state of single or multiple discharge branches, achieving bypass discharge of the leakage current and effectively reducing the temperature rise of the TVS regulator. Simultaneously, the software control logic, through power-on initialization and interrupt handling, ensures a rapid response of the discharge branches and a shutdown time not exceeding 200ms, thus balancing system load capacity and stability.

[0019] This invention significantly extends the lifespan of TVS voltage regulators, improves the system's anti-interference capability and operational reliability, and is suitable for power management scenarios in high harmonic interference environments.

[0020] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0021] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0022] Figure 1 The block diagram of the temperature rise control circuit for the resistive capacitor step-down device of the present invention is shown. Figure 2 The circuit diagram of the leakage current bypass discharge circuit of the TVS with a multi-channel structure is shown. Figure 3 A control flowchart of a microcontroller according to an embodiment of the present invention is provided; Figure 4 for Figure 3 A schematic diagram showing the correspondence between the OCP signal and the Discharge1, Discharge2, and Discharge3 signals; Figure 5 This is a simulation schematic diagram of the control circuit of the present invention; Figure 6 This is a simulation waveform diagram of the discharge circuit being turned on in this invention; Figure 7 This is a simulation waveform diagram of the discharge circuit being turned off in this invention. Detailed Implementation

[0023] Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0024] Figure 1 A block diagram illustrating the principle of the temperature rise control circuit for the resistive capacitor step-down device of the present invention is shown.

[0025] like Figure 1 As shown, the present invention provides a temperature rise control circuit for a resistor-capacitor step-down device that resists high-order harmonics, including an EMC circuit, a resistor-capacitor step-down circuit, a rectifier circuit, a TVS leakage current bypass discharge circuit, a TVS voltage regulation and leakage current sampling circuit, and a DC / DC BUCK step-down circuit connected in sequence. The EMC circuit is used to acquire the three-phase four-wire input power signal, perform harmonic suppression and interference filtering, and obtain the filtered AC signal. The RC step-down circuit is used to step down the filtered AC signal to obtain a stepped-down AC signal. The rectifier circuit, which uses a full-bridge circuit composed of rectifier diodes, is used to convert the stepped-down AC signal into a DC signal. The TVS leakage current bypass discharge circuit is used to receive the control signal Discharge from the microcontroller and dynamically adjust the on / off state of the transistor control circuit according to the leakage current sampling value to bypass the TVS leakage current. The TVS voltage regulator and leakage current sampling circuit is used to regulate the DC signal and sample the leakage current, and the TVS leakage current sampling value is used as the OCP sampling signal to be output to the controller. A DC / DC buck converter is used to step down a regulated DC signal and output the target voltage to the load.

[0026] Specifically, the three-phase four-wire input consists of terminals A, B, C, and N, providing a phase voltage of 230V and a line voltage of 400V. The EMC circuit is used for lightning protection, harmonic filtering, and line interference filtering to ensure stable system operation. The RC step-down circuit uses the capacitive reactance of capacitors C1, C2, and C3 to reduce voltage, while resistors R6, R7, and R8 discharge residual voltage. The rectifier circuit, a full-bridge circuit composed of rectifier diodes, converts AC to DC. The TVS voltage regulation and leakage current sampling circuit uses TVS diode D2 for voltage regulation, resistor R4 for sampling TVS leakage current, and R5 and C5 to form an RC filter to remove glitches in the voltage sampling signal. The TVS leakage current bypass discharge circuit bypasses part of the TVS leakage current through discharge resistor R1. The transistor control circuit, composed of transistor Q1 and resistors R2 and R3, controls the on / off state of discharge resistor R1. DC / DC BUCK step-down circuit: Steps down 20.5V to 3.3V for system use; C6 is the output filter capacitor.

[0027] The working principle is as follows: the three-phase four-wire input is filtered and protected by the EMC circuit, and then enters the RC step-down circuit, where the voltage is reduced by the capacitive reactance; the rectifier circuit converts the AC power to DC power; the TVS voltage regulation and leakage current sampling circuit is used for voltage regulation and leakage current sampling; the TVS leakage current bypass discharge circuit bypasses part of the TVS leakage current through the discharge resistor R1, reducing the temperature rise of the TVS tube; the DC / DC BUCK step-down circuit reduces the voltage from 20.5V to 3.3V, providing a stable power supply for the system.

[0028] This invention aims to address the reliability problem of temperature rise of TVS tubes in traditional RC step-down solutions for low-end meters in the smart grid field under harmonics. It designs a temperature rise control circuit for RC step-down devices that resists high-order harmonics. The implementation of this control circuit includes hardware circuitry and microcontroller control steps.

[0029] The hardware implementation is as follows: Step 1: EMC circuit design and RC step-down circuit design Select capacitors C1, C2, and C3, and resistors R6, R7, and R8 to ensure specifications such as withstand voltage, power consumption, and temperature rise, ensuring the EMC circuit can effectively suppress harmonics and interference. Capacitor C1 is connected in parallel with resistor R6, capacitor C2 in parallel with resistor R7, and capacitor C3 in parallel with resistor R8. One end of each capacitor (C1, C2, C3) is connected to the A, B, and C phase output terminals of the EMC circuit, respectively, and the other end is connected to the input terminal of the rectifier circuit. The N-phase output terminal of the EMC circuit is connected to the input terminal of the rectifier circuit. Resistors R6, R7, and R8 are used to discharge residual voltage. The capacitive reactance of capacitors C1, C2, and C3 is calculated as follows:

[0030] By selecting appropriate capacitor values, the load-carrying capacity of the RC step-down circuit can be ensured to meet the requirements of the downstream load while keeping costs low.

[0031] Step 2: Rectifier Circuit Design A full-bridge circuit is constructed using rectifier diodes to convert AC to DC. The output of the rectifier circuit is then connected to the input of the TVS voltage regulator and leakage current sampling circuit.

[0032] Step 3: Design of TVS voltage regulator and leakage current sampling circuit The output terminal of the rectifier circuit is connected to the positive terminal of diode D1, and the negative terminal of diode D1 is connected to the positive terminal of capacitor C4 and the input terminal of the TVS voltage regulator and leakage current sampling circuit. The negative terminal of capacitor C4 is grounded. The capacitor C4 is used for energy storage and filtering, and the diode D1 is used to realize the reverse power failure prevention function. That is, when the circuit is powered off, if the TVS leakage current bypass discharge circuit fails to turn off in time, it can prevent the energy stored in capacitor C4 from flowing back into the discharge circuit. The negative terminal of the TVS diode D2 is connected to the negative terminal of the diode D1 as the input terminal of the TVS voltage regulation and leakage current sampling circuit. The positive terminal of the TVS diode D2 is connected to one end of the resistors R4 and R5. The other end of the resistor R5 is connected to one end of the capacitor C5 and serves as the output of the TVS voltage regulation and leakage current sampling circuit, generating an OCP sampling signal that is connected to the corresponding input terminal of the controller. The other end of the capacitor C5 and the other end of the resistor R4 are grounded.

[0033] For the regulated voltage, select the appropriate TVS diode model and resistor R4 value to sample the TVS leakage current. Select resistor R5 and capacitor C5 values ​​to form an RC filter circuit. The TVS diode leakage current is affected by the clamping voltage VTVS and the equivalent resistance RTVS. The formulas for calculating the TVS diode leakage current and power dissipation are as follows: ,

[0034] Step 4: Design of TVS Leakage Current Bypass Discharge Circuit The TVS leakage current bypass discharge circuit can be a single-channel or multi-channel structure. Taking the single-channel structure as an example, a single discharge circuit includes a discharge resistor R1 and a transistor control circuit composed of transistor Q1, resistors R2 and R3. One end of the discharge resistor R1 is connected to the output terminal of the rectifier circuit, and the other end is connected to the collector of transistor Q1. The base of transistor Q1 is connected to one end of resistor R2, and the other end of resistor R2 is connected to the control signal output terminal Discharge of the microcontroller. The connection point between resistor R2 and the base of transistor Q1 is connected to one end of resistor R3, and the other end of resistor R3 is grounded.

[0035] The discharge resistor R1 serves to bypass the leakage current of the TVS diode. The power calculation for the discharge resistor R1 is shown below: , Bypass current When selecting transistor Q1, the collector current needs to be considered to ensure that the transistor operates in the linear region. Given transistor Q1's β and base drive voltage VDischarge, the formulas for calculating the base current and collector current are as follows: ,

[0036] Step 5: DC / DC Buck Step-Down Circuit Design Select a DC / DC BUCK chip to step down the 20.5V to 3.3V. Connect the input of the DC / DC BUCK circuit to the output of the TVS regulator and leakage current sampling circuit, and connect the output to the system load. Select the appropriate capacitance value for the output filter capacitor C6 to ensure stable output voltage.

[0037] Where the input voltage is set to VIN and the output voltage to VOUT, the duty cycle of the DC / DC converter is: Assuming the switching frequency is fsw and the inductor current ripple is ΔIL, the formula for calculating the inductance value is as follows:

[0038] When the TVS leakage current bypass discharge circuit has a multi-channel structure; taking a three-channel structure as an example, such asFigure 2 As shown.

[0039] The control steps of the microcontroller are as follows: Step 1: System initialization, configure the microcontroller's GPIO pins, initialize Discharge1, Discharge2 and Discharge3 signals to low level, and disable the TVS leakage current bypass discharge circuit.

[0040] Step 2: Configure the ADC module and set the OCP signal sampling channel and sampling rate.

[0041] Step 3: OCP signal sampling. When the timer is interrupted, the ADC sampling function is called to obtain the voltage value of the OCP signal.

[0042] Step 4: OCP signal comparison and Discharge signal control; compare the OCP signal with preset high, medium, and low thresholds; for example... Figure 3 As shown in the diagram, the correspondence between the OCP signal and the Discharge signal can be divided into four cases. The first method is to set the Discharge1, Discharge2 and Discharge3 signals to high level and open the three-way discharge circuit if the OCP signal is greater than the high threshold. The second method is to set Discharge1 and Discharge2 signals to high level and Discharge3 signal to low level if the OCP signal is between the high threshold and the medium threshold, thereby opening the two discharge circuits. The third method is to set the Discharge1 signal to high level and the Discharge2 and Discharge3 signals to low level if the OCP signal is between the middle threshold and the low threshold, thus opening one discharge circuit. Fourthly, if the OCP signal is less than the low threshold, set the Discharge1, Discharge2 and Discharge3 signals to low level and shut down the three discharge circuits.

[0043] Step 5: Real-time response optimization. The OCP signal sampling and comparison logic is placed within the timer interrupt service function to ensure a response within 200ms. When the OCP signal falls below the low threshold, the discharge circuit is immediately shut down to avoid the risk of system reset.

[0044] Referring to Figure 4, the present invention was simulated and verified using the LTSpice tool. Figures 5 and 6 show the simulation results, taking a single-channel discharge circuit as an example.

[0045] Figure 5To simulate the discharge circuit being turned on, the current I(R1) through the discharge circuit is approximately 14mA, and the leakage current I(R4) through the TVS is approximately 17mA.

[0046] Figure 6 To simulate the discharge circuit being turned off, the current I(R1) through the discharge circuit is approximately 0mA, and the leakage current I(R4) through the TVS is approximately 31mA.

[0047] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A temperature rise control circuit for a resistive-capacitive step-down device that resists high-order harmonics, characterized in that, The EMC circuit, the resistance-capacitance voltage reduction circuit, the rectifier circuit, the TVS leakage current bypass discharge circuit, the TVS voltage stabilization and leakage current sampling circuit, and the DC / DC BUCK voltage reduction circuit are sequentially connected. The EMC circuit is used for obtaining three-phase four-wire input power signals, performing harmonic suppression and interference filtering, and obtaining filtered alternating current signals. The resistance-capacitance voltage reduction circuit is used for reducing the voltage of the filtered alternating current signals and obtaining reduced alternating current signals. The rectifier circuit is a full-bridge circuit composed of rectifier diodes, and is used for converting the reduced alternating current signals into direct current signals. The TVS leakage current bypass discharge circuit is used for receiving a control signal Discharge of a single-chip microcomputer, dynamically adjusting the on-off state of a triode control circuit according to a leakage current sampling value, and bypassing part of the TVS leakage current. The TVS voltage stabilization and leakage current sampling circuit is used for stabilizing the direct current signals and sampling the leakage current, and outputs a TVS leakage current sampling value as an OCP sampling signal to a controller. The DC / DC BUCK voltage reduction circuit is used for reducing the voltage of the stabilized direct current signals and outputting a target voltage to a load.

2. The high harmonic suppression resistor-capacitor voltage dropper temperature control circuit of claim 1, wherein, The resistance-capacitance voltage reduction circuit includes capacitors C1-C3 and resistors R6-R8, the capacitor C1 is connected in parallel with the resistor R6, the capacitor C2 is connected in parallel with the resistor R7, and the capacitor C3 is connected in parallel with the resistor R8; one end of each of the capacitors C1, C2 and C3 is connected to an A-phase, B-phase or C-phase output terminal of the EMC circuit, and the other end of each of the capacitors C1, C2 and C3 is connected to an input terminal of the rectifier circuit; and an N-phase output terminal of the EMC circuit is connected to the input terminal of the rectifier circuit.

3. The high harmonic suppression resistor-capacitor voltage dropper temperature control circuit of claim 1, wherein, The TVS voltage stabilization and leakage current sampling circuit includes a TVS tube D2, resistors R4 and R5, and a capacitor C5. The output terminal of the rectifier circuit is connected to the positive electrode of a diode D1, the negative electrode of the diode D1 is connected to the positive electrode of a capacitor C4 and an input terminal of the TVS voltage stabilization and leakage current sampling circuit, and the negative electrode of the capacitor C4 is grounded; the capacitor C4 is used for energy storage and filtering, and the diode D1 is used for realizing a power failure anti-reverse function, i.e., when the circuit is powered off, if the TVS leakage current bypass discharge circuit fails to turn off in time, the energy stored in the capacitor C4 can be prevented from flowing reversely into the discharge circuit; The negative electrode of the TVS tube D2 is connected to the negative electrode of the diode D1 as the input terminal of the TVS voltage stabilization and leakage current sampling circuit, the positive electrode of the TVS tube D2 is connected to one end of the resistor R4 and the resistor R5, the other end of the resistor R5 is connected to one end of the capacitor C5 and serves as the output terminal of the TVS voltage stabilization and leakage current sampling circuit, generates an OCP sampling signal and inputs the OCP sampling signal to a corresponding input terminal of a controller, and the other end of the capacitor C5 and the other end of the resistor R4 are grounded.

4. The high harmonic suppression resistor-capacitor voltage dropper temperature control circuit of claim 1, wherein, The TVS leakage current bypass discharge circuit is a single-path or multi-path structure. When it is a single-path structure, the single discharge circuit includes a discharge resistor R1 and a transistor control circuit composed of a transistor Q1, resistors R2 and R3, one end of the discharge resistor R1 is connected to the output end of the rectifier circuit, the other end is connected to the collector of the transistor Q1, one end of the resistor R2 is connected to the base of the transistor Q1, the other end of the resistor R2 is connected to the control signal output end of the single-chip microcomputer, the connection point of the resistor R2 and the base of the transistor Q1 is connected to one end of the resistor R3, the other end of the resistor R3 is grounded.

5. The high harmonic suppression resistor-capacitor voltage dropper temperature control circuit of claim 1, wherein, The TVS leakage current bypass discharge circuit is a single-path or multi-path structure; When it is a multi-path structure, n discharge branches in parallel are included, n≥2; each discharge branch is composed of an independent discharge resistor and a transistor control circuit; the transistor control circuit is controlled by the n-stage threshold voltage comparison logic of the controller, so that different discharge branches are activated according to the TVS leakage current sampling value.

6. The high harmonic suppression resistor-capacitor voltage dropper temperature control circuit of claim 5, wherein, The n-stage threshold voltage comparison logic is provided with n threshold values, which are the first threshold value to the nth threshold value from low to high, and are matched with the corresponding parallel discharge branches; When the TVS leakage current sampling value is lower than the first threshold value, all discharge branches are turned off; When the TVS leakage current sampling value is between the first threshold value and the second threshold value, the first discharge branch is turned on; By analogy, when the TVS leakage current sampling value is between the (n-1)th threshold value and the nth threshold value, the first to (n-1)th discharge branches are turned on; When the TVS leakage current sampling value is greater than the nth threshold value, all discharge branches are turned on.

7. The high harmonic suppression resistor-capacitor voltage dropper temperature control circuit of claim 6, wherein, In the multi-stage threshold voltage comparison logic of the controller, the closing time of the discharge branch is not more than 200 ms, so as to ensure that the system can quickly release the load capacity when the TVS leakage current decreases.

8. The high harmonic suppression resistor-capacitor voltage dropper temperature control circuit of claim 1, wherein: The TVS voltage stabilizing and leakage current sampling circuit includes a resistor R4, an RC filter circuit composed of a resistor R5 and a capacitor C5, and a TVS voltage stabilizing tube D2, the negative electrode of the TVS voltage stabilizing tube D2 is connected to the negative electrode of a diode D1, the positive electrode of the TVS voltage stabilizing tube D2 is connected to one end of the resistor R4, the resistor R4 is a TVS leakage current sampling resistor, which is used to convert the TVS leakage current into a voltage signal, the other end of the resistor R4 is grounded; the resistor R5 and the capacitor C5 constitute an RC filter circuit, which is used to filter glitches of the voltage sampling signal, and the connection point of the resistor R5 and the capacitor C5 serves as the output of the TVS voltage stabilizing and leakage current sampling circuit, and outputs an OCP sampling signal to the controller.

9. The high harmonic suppression resistor-capacitor voltage dropper temperature control circuit of claim 1, wherein, The input end of the DC / DC BUCK voltage reduction circuit is connected to the output end of the TVS voltage stabilizing and leakage current sampling circuit, the output end of the DC / DC BUCK voltage reduction circuit is connected to the system load, and one end of a filter capacitor C6 is connected, the other end of the capacitor C6 is grounded.

10. The high harmonic suppression resistor-capacitor voltage dropper temperature control circuit of claim 1, wherein, The single-chip microcomputer performs the following control steps to dynamically adjust the on-off state of the bypass discharge circuit, including: S1, power-on initialization, configuring the control signal of the transistor control circuit in the TVS leakage current bypass discharge circuit to be low, and closing the TVS leakage current bypass discharge circuit; S2, interrupt processing, when the timer interrupt, call ADC sampling function, real-time acquisition TVS leakage current sampling value, namely OCP sampling signal, compare the TVS leakage current sampling value with the preset threshold value; According to the comparison result adjusts the control signal level, dynamic control discharge branch state; If the TVS leakage current bypass discharge circuit is single path structure, when the TVS leakage current sampling value is higher than the single path threshold value, the discharge branch is turned on; If the TVS leakage current bypass discharge circuit is multi-path structure, n-stage threshold voltage comparison logic is adopted, from low to high, respectively, the first threshold to the nth threshold value, matched with the corresponding parallel discharge branch; When the TVS leakage current sampling value is lower than the first threshold value, all discharge branches are turned off; When the TVS leakage current sampling value is between the first threshold value and the second threshold value, the first discharge branch is turned on; By analogy, when the TVS leakage current sampling value is between the (n-1)th threshold value and the nth threshold value, the first to (n-1) discharge branches are turned on; When the TVS leakage current sampling value is greater than the nth threshold value, all discharge branches are turned on.

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