Overvoltage protection circuit

Abstract

The invention provides an overvoltage protection circuit which comprises an abnormal voltage detection module, an overvoltage protection threshold adjusting module, a comparator and an on-off control module, the input end of the abnormal voltage detection module is connected to an input power supply, the first output end of the abnormal voltage detection module is connected to the negative electrode input end of the comparator, and the second output end of the abnormal voltage detection module is connected to the negative electrode input end of the comparator. The second output end of the abnormal voltage detection module is grounded, the positive pole input end of the comparator is connected to the overvoltage protection threshold value adjusting module, the output end of the comparator is connected to the input end of the on-off control module, the first output end of the on-off control module is connected to the inversion control circuit, and the power supply end of the on-off control module is connected to an input power supply. The second output end of the on-off control module is grounded. According to the application, the overvoltage protection threshold can be adjusted through the overvoltage protection threshold adjusting module, so that the circuit adapts to diversified working scenes, and meanwhile, the cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of overvoltage protection, and in particular to an overvoltage protection circuit. Background Art

[0002] Inverter control circuits such as H-bridge drive circuits, half-bridge drive circuits, and three-phase full-bridge drive circuits are common power electronic circuits used to control the rotation direction of motors or to achieve bidirectional current drive of loads such as DC motors and stepper motors. In inverter control circuits, metal oxide field effect transistors, as key switching elements, are susceptible to transient overvoltage shocks, resulting in damage or performance degradation. Overvoltage protection is particularly important, especially in complex working environments such as power grid fluctuations, load mutations, etc.

[0003] In the prior art, the design schemes for overvoltage protection circuits of inverter control circuits mostly adopt a fixed overvoltage protection threshold. Traditional overvoltage protection circuits with fixed overvoltage protection thresholds are prone to false triggering or protection failure under different temperature conditions (such as high temperature or low temperature). This is because the characteristic parameters of the metal semiconductor field effect transistor in the inverter control circuit (such as threshold voltage, on-resistance, etc.) will change with temperature, and the fixed overvoltage protection threshold cannot adapt to such changes. Once the protection parameters of the fixed-threshold overvoltage protection circuit provided by the prior art are set, it is difficult to adjust according to actual needs and cannot meet diverse working scenarios. Ultimately, in order to adapt to different scenarios, circuit design needs to be performed one by one for each scenario, which increases costs. Summary of the invention

[0004] In view of this, the purpose of the present application is to at least provide an overvoltage protection circuit, which realizes adjustable overvoltage protection threshold through an overvoltage protection threshold adjustment module, so that the circuit can adapt to various working scenarios while reducing costs.

[0005] This application mainly includes the following aspects:

[0006] In a first aspect, an embodiment of the present application provides an overvoltage protection circuit, which includes an abnormal voltage detection module, an overvoltage protection threshold adjustment module, a comparator and an on-off control module, wherein the input end of the abnormal voltage detection module is connected to an input power supply, the first output end of the abnormal voltage detection module is connected to a negative input end of the comparator, the second output end of the abnormal voltage detection module is grounded, the positive input end of the comparator is connected to the overvoltage protection threshold adjustment module, the output end of the comparator is connected to the input end of the on-off control module, the first output end of the on-off control module is connected to an inverter control circuit, the power supply end of the on-off control module is connected to the input power supply, and the second output end of the on-off control module is grounded.

[0007] In one possible implementation, the overvoltage protection threshold adjustment module includes a sliding rheostat and a first power supply, wherein the first fixed end of the sliding rheostat is connected to the first power supply, the second fixed end of the sliding rheostat is grounded, and the sliding end of the sliding rheostat is connected to the positive input end of the comparator.

[0008] In one possible implementation, the abnormal voltage detection module includes a first voltage-dividing resistor, a second voltage-dividing resistor and a third voltage-dividing resistor, wherein one end of the first voltage-dividing resistor is connected to an input power supply, the other end of the first voltage-dividing resistor is connected to one end of the second voltage-dividing resistor, the other end of the second voltage-dividing resistor is respectively connected to one end of the third voltage-dividing resistor and the negative input end of the comparator, and the other end of the third voltage-dividing resistor is grounded.

[0009] In a possible implementation manner, the second voltage-dividing resistor is a thermistor.

[0010] In a possible implementation, the overvoltage protection circuit also includes a first current limiting resistor and a second power supply, wherein one end of the first current limiting resistor is respectively connected to the second power supply and the positive power supply input of the comparator, the other end of the first current limiting resistor is respectively connected to the output of the comparator and the input of the on-off control module, and the negative power supply input of the comparator is grounded.

[0011] In a possible implementation, the on-off control module includes a first control switch, a voltage divider unit, and a second control switch, wherein the control end of the first control switch is connected to the output end of the comparator, the first connection end of the first control switch is respectively connected to the control end of the second control switch and one end of the voltage divider unit, the second connection end of the first control switch is grounded, the first connection end of the second control switch is respectively connected to the other end of the voltage divider unit and the input power supply, and the second connection end of the second control switch is connected to the inverter control circuit.

[0012] In a possible implementation, the on-off control module further includes a second current limiting resistor, wherein one end of the second current limiting resistor is connected to the first connection end of the first control switch, and the other end of the second current limiting resistor is respectively connected to the control end of the second control switch and one end of the voltage dividing unit.

[0013] In a possible implementation, the voltage dividing unit includes a fourth voltage dividing resistor and a voltage regulator tube, one end of the fourth voltage dividing resistor is connected to the anode of the voltage regulator tube and then connected to the other end of the second current limiting resistor, and the other end of the fourth voltage dividing resistor is connected to the cathode of the voltage regulator tube and then connected to the input power supply.

[0014] In a possible implementation, the overvoltage protection circuit also includes a filter capacitor and a transient voltage suppressor, wherein one end of the filter capacitor is connected to one end of the transient voltage suppressor and then connected to an input power supply, and the other end of the filter capacitor is connected to the other end of the transient voltage suppressor and then grounded.

[0015] In a possible implementation, the inverter control circuit includes an H-bridge / half-bridge / full-bridge drive control circuit.

[0016] An overvoltage protection circuit provided by an embodiment of the present application includes an abnormal voltage detection module, an overvoltage protection threshold adjustment module, a comparator and an on-off control module, wherein the input end of the abnormal voltage detection module is connected to an input power supply, the first output end of the abnormal voltage detection module is connected to the negative input end of the comparator, the second output end of the abnormal voltage detection module is grounded, the positive input end of the comparator is connected to the overvoltage protection threshold adjustment module, the output end of the comparator is connected to the input end of the on-off control module, the first output end of the on-off control module is connected to an inverter control circuit, the power supply end of the on-off control module is connected to the input power supply, and the second output end of the on-off control module is grounded. The present application realizes that the overvoltage protection threshold is adjustable through the overvoltage protection threshold adjustment module, so that the circuit can adapt to various working scenarios while reducing costs.

[0017] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 One of the structural schematic diagrams of an overvoltage protection circuit provided in an embodiment of the present application is shown;

[0020] Figure 2 A second structural schematic diagram of an overvoltage protection circuit provided in an embodiment of the present application is shown;

[0021] Figure 3 A schematic structural diagram of an on-off control module provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0022] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowchart can be implemented out of sequence, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art, under the guidance of the content of the present application, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0023] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0024] Traditional overvoltage protection circuits with fixed overvoltage protection thresholds are prone to false triggering or protection failure under different temperature conditions (such as high or low temperature). This is because the characteristic parameters of the metal oxide field effect transistor MOSFET in the inverter control circuit (such as threshold voltage, on-resistance, etc.) will change with temperature, and the fixed overvoltage protection threshold cannot adapt to such changes, which may lead to untimely or false protection of the inverter control circuit, thereby affecting the stability and reliability of the control system in which the entire inverter control circuit is located.

[0025] Once the protection parameters of the overvoltage protection circuit with a fixed overvoltage protection threshold provided in the prior art are set, it is difficult to adjust it according to the actual operating environment requirements of the inverter control circuit, that is, it cannot meet the diverse working scenarios, reduces the user experience of the system formed by the overvoltage protection circuit combined with the inverter control circuit and the system flexibility, and increases the risk of system failure, especially in complex working environments, such as power grid fluctuations, sudden load changes, etc., which increases the risk of system failure.

[0026] Based on this, an embodiment of the present application provides an overvoltage protection circuit, which realizes adjustable overvoltage protection threshold through an overvoltage protection threshold adjustment module, so that the circuit can adapt to diversified working scenarios while reducing costs, as follows:

[0027] See also Figure 1 , Figure 1 FIG. 1 shows one of the structural schematic diagrams of an overvoltage protection circuit provided in an embodiment of the present application. Figure 1 As shown, the overvoltage protection circuit provided in the embodiment of the present application includes an abnormal voltage detection module 1, an overvoltage protection threshold adjustment module 2, a comparator U1, an on-off control module 3 and a filtering protection circuit 4.

[0028] Among them, the input end of the abnormal voltage detection module 1 is connected to the input power supply VCC1, the first output end of the abnormal voltage detection module 1 is connected to the negative input end of the comparator U1, the positive input end of the comparator U1 is connected to the overvoltage protection threshold adjustment module 2, the output end of the comparator U1 is connected to the input end of the on-off control module 3, the first output end of the on-off control module 3 is connected to the inverter control circuit 5, the second output end of the on-off control module 3 is grounded, and the power supply end of the on-off control module 3 is connected to the input power supply VCC1.

[0029] In a specific implementation, the input end of the filter protection circuit 4 is connected to the input power supply VCC1, and the output end of the filter protection circuit 4 is grounded.

[0030] In a preferred embodiment, see Figure 2 , Figure 2 FIG. 2 shows a second structural diagram of an overvoltage protection circuit provided in an embodiment of the present application. Figure 2 As shown, the overvoltage protection threshold adjustment module 2 includes a sliding resistor RN and a first power supply VCC2, wherein the first fixed end of the sliding resistor RN is connected to the first power supply VCC2, the second fixed end of the sliding resistor RN is grounded GND, and the sliding end of the sliding resistor RN is connected to the positive input end of the comparator U2.

[0031] In a preferred embodiment, the abnormal voltage detection module includes a first voltage-dividing resistor R1, a second voltage-dividing resistor R2 and a third voltage-dividing resistor R3.

[0032] Among them, one end of the first voltage-dividing resistor R1 is connected to the input power supply VCC1, the other end of the first voltage-dividing resistor R1 is connected to one end of the second voltage-dividing resistor R2, the other end of the second voltage-dividing resistor R2 is respectively connected to one end of the third voltage-dividing resistor R3 and the negative input end of the comparator U2, and the other end of the third voltage-dividing resistor R3 is grounded.

[0033] Preferably, the second voltage-dividing resistor R2 is a thermistor.

[0034] The first voltage-dividing resistor R1, the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3 form a voltage-dividing network. The input voltage V- corresponding to the negative input terminal of the comparator U2 is the midpoint voltage between the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3. Specifically:

[0035] V-=(VCC1×R3) / (R1+R2+R3), wherein the first voltage-dividing resistor R1 and the third voltage-dividing resistor R3 are ordinary resistors. As the temperature increases, the resistivity of their materials will also increase slightly, resulting in a slightly larger resistance value. The second voltage-dividing resistor R2 is a thermistor. The resistance value of the thermistor decreases as the temperature increases and increases as the temperature decreases. When the circuit temperature increases, the second voltage-dividing resistor R2 decreases, and the resistance values ​​of the first voltage-dividing resistor R1 and the third voltage-dividing resistor R3 increase, so that V- can remain stable.

[0036] In addition, if a temperature-sensitive load or sensor is connected to the overvoltage protection circuit, changes in the temperature environment of the entire circuit will lead to some non-ideal effects, such as changes in parasitic capacitance and inductance. These devices require certain temperature compensation. In this application, the resistance compensation in the corresponding temperature environment is mainly achieved by selecting the corresponding model of the second voltage-divider resistor R2 based on the characteristic that the resistance of the second voltage-divider resistor R2 changes with temperature.

[0037] For the selection of the compensation value of the second voltage-dividing resistor R2, it is necessary to test the fluctuation of V- corresponding to the overvoltage protection circuit at different temperatures in the actual application environment, so as to confirm the compensation value of the second voltage-dividing resistor R2 at the same temperature. In applications with high reliability requirements, in order to ensure the protection effect under extreme temperature conditions, you can choose a second voltage-dividing resistor with a larger resistance sliding when the unit temperature rises or falls. That is, the value of R2 decreases more with increasing temperature, the collected V- is larger, and the overvoltage protection is more easily triggered.

[0038] In applications where the accuracy of the overvoltage protection threshold is not high but there is a need for circuit stability, in order to reduce the risk of false triggering, a second voltage-dividing resistor R2 with a relatively small resistance sliding value under unit temperature rise or fall can be selected. That is, the value of R2 decreases smaller as the temperature rises, the collected V- is smaller, and it is less likely to falsely trigger the overvoltage protection.

[0039] The positive input terminal of the comparator U2 is connected to the sliding end of the sliding resistor RN. The sliding resistor RN is used to control the overvoltage protection threshold. The positive input reference voltage of the comparator U2 is: Vref = (VCC1×Ra) / R, where R is the total resistance of the sliding resistor RN, and Ra is the resistance between the sliding end of the sliding resistor RN and the ground GND.

[0040] In the comparator U2, when the positive input voltage Vref is greater than the negative input voltage V-, the comparator U2 outputs a high level, and when the negative input voltage V- is greater than the positive input voltage Vref, the comparator U2 outputs a low level.

[0041] In a preferred embodiment, the overvoltage protection circuit also includes a first current limiting resistor R4 and a second power supply VCC3, wherein one end of the first current limiting resistor R4 is respectively connected to the second power supply VCC3 and the positive power supply input terminal of the comparator U2, and the other end of the first current limiting resistor R4 is respectively connected to the output terminal of the comparator U2 and the input terminal of the on-off control module 3, and the negative power supply input terminal of the comparator U2 is grounded.

[0042] In the present application, the first power supply VCC2 can be +5V, the second power supply VCC2 can be +10V, and the first current limiting resistor R4 prevents the second power supply VCC2 and the output end of the comparator U2 from being misconnected and damaging the comparator U2. By connecting a first current limiting resistor R4 in series, the current flowing through the output end of the comparator U2 can be effectively limited to protect the comparator U2.

[0043] Preferably, see Figure 3 , Figure 3 FIG. 2 shows a schematic diagram of the structure of an on-off control module provided in an embodiment of the present application. Figure 3 As shown, the on-off control module 3 includes a first control switch K1 , a voltage dividing unit 31 and a second control switch K2 .

[0044] Among them, the control end of the first control switch K1 is connected to the output end of the comparator U2 (not shown in the figure), the first connection end of the first control switch K1 is respectively connected to the control end of the second control switch K2 and one end of the voltage dividing unit 31, the second connection end of the first control switch K1 is grounded GND, the first connection end of the second control switch K2 is respectively connected to the other end of the voltage dividing unit 31 and the input power supply VCC1, and the second connection end of the second control switch K2 is connected to the inverter control circuit 5.

[0045] In a preferred embodiment, if Figure 2 As shown, the on-off control module 3 also includes a second current limiting resistor R5, and the voltage dividing unit 31 includes a fourth voltage dividing resistor R6 and a voltage regulator D1. One end of the fourth voltage dividing resistor R6 is connected to the anode of the voltage regulator D1 and then connected to the other end of the second current limiting resistor R5 and the control end of the second control switch K2. The other end of the fourth voltage dividing resistor R6 is connected to the cathode of the voltage regulator D1 and then connected to the input power supply VCC1 and the first connection end of the second control switch K2. One end of the second current limiting resistor R5 is connected to the first connection end of the first control switch K1.

[0046] Preferably, Figure 2 As shown, the first control switch K1 can be an NPN transistor, the control end of the first control switch K1 is the base of the NPN transistor, the first connection end of the first control switch K1 is the collector of the NPN transistor, and the second connection end of the first control switch K1 is the emitter of the NPN transistor.

[0047] The second control switch K2 can be a P-type field effect transistor, the control end of the second control switch K2 is the gate of the P-type field effect transistor, the first connection end of the second control switch K2 is the source of the P-type field effect transistor, and the second connection end of the second control switch K2 is the drain of the P-type field effect transistor.

[0048] The second current limiting resistor R5 is used to limit the current of the input of the first connection end of the first control switch K1 to protect the first control switch K1 from overcurrent breakdown. The fourth voltage-dividing resistor R6 and the second current-limiting resistor R5 form a series voltage-dividing network. The voltage-dividing resistor R6 and the voltage difference VGS between the control end and the first connection end of the second control switch K2 and the voltage-stabilizing diode D1 ensure the stability of the VGS corresponding to the second control switch K2.

[0049] Preferably, the filtering protection circuit 4 also includes a filtering capacitor C and a transient voltage suppressor U1, wherein one end of the filtering capacitor C is connected to one end of the transient voltage suppressor U1 and then connected to the input power supply VCC1, and the other end of the filtering capacitor C is connected to the other end of the transient voltage suppressor U1 and then grounded GND.

[0050] Specifically, the filter capacitor C is used for filtering and decoupling to filter out high-frequency noise and ripple on the input power supply VCC1, ensure the power supply stability of the overvoltage protection circuit, ensure that the circuit can work stably, and improve reliability.

[0051] Transient voltage suppressor U1 can respond to and clamp transient overvoltage in a very short time, and lead the overvoltage energy generated by the input power supply VCC1 to the ground line to protect the subsequent circuit from damage. The filter capacitor C is connected in parallel with the transient voltage suppressor U1 to form an anti-interference circuit connected between the input power supply VCC1 and the low GND, providing a dual protection mechanism. The filter capacitor mainly handles high-frequency noise and transient current requirements, while the transient voltage suppressor U1 focuses on transient overvoltage protection. The combination of the two can more comprehensively protect the overvoltage protection circuit from various power supply interferences.

[0052] Preferably, the inverter control circuit 5 is an H-bridge / half-bridge / full-bridge drive control circuit.

[0053] In a specific embodiment, if Figure 2 As shown, taking the inverter control circuit 5 as an H-bridge drive control circuit as an example, the inverter control circuit 5 includes a first drive switch Q1, a second drive switch Q2, a third drive switch Q3, a fourth drive switch Q4, a load inductor L and a load resistor R7.

[0054] The first connection end of the first drive switch Q1 and the first connection end of the third drive switch Q3 are connected and connected to the second connection end of the second control switch K2. The second connection end of the first drive switch Q1 is respectively connected to one end of the load inductor L and the first connection end of the second drive switch Q2. The second connection end of the second drive switch Q2 is grounded. The first drive switch Q1 and the second drive switch Q2 form a group of bridge arms.

[0055] The other end of the load inductor L is connected to one end of the load resistor R7, the second connection end of the third drive switch Q3 is respectively connected to the other end of the load resistor R7 and the first connection end of the fourth drive switch Q4, and the second connection end of the fourth drive switch Q4 is grounded.

[0056] Control ends of the first drive switch Q1 , the second drive switch Q2 , the third drive switch Q3 , and the fourth drive switch Q4 are connected to the controller respectively.

[0057] Among them, Q1~Q4 can select N-type field effect transistors. Specifically, the control end of the drive switch is the gate of the N-type field effect transistor, the first connection end of the drive switch is the drain of the N-type field effect transistor, and the second connection end of the drive switch is the source of the N-type field effect transistor.

[0058] In a specific embodiment, if Figure 2 The circuit shown works as follows:

[0059] In response to a sliding operation performed on the sliding end of the sliding resistor RN, a specified overvoltage protection threshold is set.

[0060] When the circuit is working normally:

[0061] The negative input voltage V- corresponding to the negative input terminal of the comparator U2 is less than the positive input reference voltage Vref, the comparator U2 outputs a high level, the first control switch K1 is turned on, the gate of the second control switch K2 is grounded after passing through the second current limiting resistor R5, the fourth voltage dividing resistor R6 and the second current limiting resistor R5 form a voltage dividing network, through the input power supply VCC1, the fourth voltage dividing resistor R6, and the second current limiting resistor R5, the second control switch K2 is turned on, and the overvoltage protection circuit normally supplies power to the inverter control circuit 5.

[0062] When abnormal overvoltage occurs in the circuit:

[0063] The input voltage VCC1 increases, the divided voltage of the third voltage-dividing resistor R3 increases, and the negative input voltage V- corresponding to the negative input terminal of the comparator U2 increases. When the negative input voltage V- is greater than the positive input reference voltage Vref, the comparator U2 outputs a low level and cannot drive the first control switch K1 to turn on. Therefore, the first control switch K1 is turned off, the base of the first control switch K1 is disconnected from GND, the gate of the second control switch K2 is suspended, and the gate and source of the second control switch K2 cannot form a voltage difference. The second control switch K2 is turned off, the connection between VCC1 and the inverter control circuit 5 is disconnected, and the inverter control circuit 5 stops working, thereby achieving overvoltage protection for the inverter control circuit 5.

[0064] The benefits of this application are:

[0065] 1) The introduction of thermistors can automatically adjust the voltage division ratio according to changes in ambient temperature to ensure that the overvoltage protection threshold remains stable under different temperature conditions, thereby improving the safety and stability of the circuit.

[0066] 2) The sliding rheostat is used to achieve flexible adjustment of the overvoltage protection threshold, which enables the circuit to flexibly adjust the threshold according to actual application requirements, can be applied to more application scenarios, and increases the compatibility of the circuit.

[0067] 3) The combination of the transient voltage suppressor, the first control switch and the second control switch can quickly cut off the load current when an overvoltage condition is detected, preventing the field effect devices in the circuit from being damaged by transient high voltage shocks, thereby improving the safety and reliability of the circuit.

[0068] 4) The present invention solves the technical problems existing in the overvoltage protection scheme of power devices in the existing bridge circuit, such as temperature dependence, lack of flexibility of fixed threshold, slow transient overvoltage response, insufficient reliability and increased cost due to complex design, by introducing automatic temperature compensation, adjustable threshold, fast response and multi-layer protection mechanism. It improves the reliability of the circuit and provides a reliability basis for the stability of terminal applications. At the same time, it adopts relatively simple and common different devices for design, which effectively reduces the circuit design and application costs.

[0069] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In the several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0070] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0071] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0072] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0073] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An overvoltage protection circuit, characterized in that: The overvoltage protection circuit includes an abnormal voltage detection module, an overvoltage protection threshold adjustment module, a comparator and an on-off control module. Among them, the input end of the abnormal voltage detection module is connected to the input power supply, the first output end of the abnormal voltage detection module is connected to the negative input end of the comparator, the second output end of the abnormal voltage detection module is grounded, the positive input end of the comparator is connected to the overvoltage protection threshold adjustment module, the output end of the comparator is connected to the input end of the on-off control module, the first output end of the on-off control module is connected to the inverter control circuit, the power supply end of the on-off control module is connected to the input power supply, and the second output end of the on-off control module is grounded.

2. The overvoltage protection circuit according to claim 1, characterized in that: The overvoltage protection threshold adjustment module includes a sliding resistor and a first power supply. The first fixed end of the sliding rheostat is connected to the first power supply, the second fixed end of the sliding rheostat is grounded, and the sliding end of the sliding rheostat is connected to the positive input end of the comparator.

3. The overvoltage protection circuit according to claim 1, characterized in that: The abnormal voltage detection module includes a first voltage-dividing resistor, a second voltage-dividing resistor and a third voltage-dividing resistor. Among them, one end of the first voltage-dividing resistor is connected to the input power supply, the other end of the first voltage-dividing resistor is connected to one end of the second voltage-dividing resistor, the other end of the second voltage-dividing resistor is respectively connected to one end of the third voltage-dividing resistor and the negative input end of the comparator, and the other end of the third voltage-dividing resistor is grounded.

4. The overvoltage protection circuit according to claim 3, characterized in that: The second voltage-dividing resistor is a thermistor.

5. The overvoltage protection circuit according to claim 1, characterized in that: The overvoltage protection circuit also includes a first current limiting resistor and a second power supply. Among them, one end of the first current limiting resistor is respectively connected to the second power supply and the positive power input terminal of the comparator, the other end of the first current limiting resistor is respectively connected to the output terminal of the comparator and the input terminal of the on-off control module, and the negative power input terminal of the comparator is grounded.

6. The overvoltage protection circuit according to claim 1, characterized in that: The on-off control module includes a first control switch, a voltage dividing unit and a second control switch. The control end of the first control switch is connected to the output end of the comparator, the first connection end of the first control switch is respectively connected to the control end of the second control switch and one end of the voltage dividing unit, and the second connection end of the first control switch is grounded. The first connection end of the second control switch is respectively connected to the other end of the voltage dividing unit and the input power supply, and the second connection end of the second control switch is connected to the inverter control circuit.

7. The overvoltage protection circuit according to claim 6, characterized in that: The on-off control module also includes a second current limiting resistor, One end of the second current limiting resistor is connected to the first connection end of the first control switch, and the other end of the second current limiting resistor is connected to the control end of the second control switch and one end of the voltage dividing unit respectively.

8. The overvoltage protection circuit according to claim 7, characterized in that: The voltage dividing unit includes a fourth voltage dividing resistor and a voltage regulator tube. One end of the fourth voltage-dividing resistor is connected to the anode of the voltage-stabilizing tube and then connected to the other end of the second current-limiting resistor. The other end of the fourth voltage-dividing resistor is connected to the cathode of the voltage-stabilizing tube and then connected to the input power supply.

9. The overvoltage protection circuit according to any one of claims 1 to 8, characterized in that: The overvoltage protection circuit also includes a filter capacitor and a transient voltage suppressor. One end of the filter capacitor is connected to one end of the transient voltage suppressor and then connected to the input power supply, and the other end of the filter capacitor is connected to the other end of the transient voltage suppressor and then grounded.

10. The overvoltage protection circuit according to any one of claims 1 to 8, characterized in that: The inverter control circuit includes an H-bridge / half-bridge / full-bridge drive control circuit.

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