Return difference overvoltage protection circuit

Abstract

The utility model provides a return difference overvoltage protection circuit, and belongs to the technical field of overvoltage protection. The return difference overvoltage protection circuit comprises a first overvoltage detection module, a second overvoltage detection module and a main control module, the first overvoltage detection module comprises a first comparison circuit and a first return difference circuit; the second overvoltage detection module comprises a second comparison circuit and a second return difference circuit; the first end of the first comparison circuit is used for connecting a positive bus, the second end of the first comparison circuit is connected with the first end of the first comparison circuit through the first return difference circuit, and the third end of the first comparison circuit is connected with the main control module; the first end of the second comparison circuit is used for connecting a negative bus, the second end of the second comparison circuit is connected with the first end of the second comparison circuit through the second return difference circuit, and the third end of the second comparison circuit is connected with the main control module. The problem that the bus voltage oscillates back and forth near the overvoltage value can be solved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of overvoltage protection, and particularly relates to a hysteresis overvoltage protection circuit. BACKGROUND

[0002] In a single-stage energy storage module adopting an "I" type three-level topology, there is an inherent problem of midpoint voltage imbalance. Especially in industrial and commercial energy storage application scenarios, the battery side is generally not equipped with a neutral line, and the N line of the module AC side is directly connected at the midpoint of the bus capacitor of the module itself. When the load side experiences a mutation or imbalance, the midpoint of the bus capacitor is more likely to be unbalanced. This imbalance may cause the voltage of one side of the bus to be too high, which not only affects the output waveform quality, but also may cause the bus capacitor and IGBT to be damaged due to overvoltage.

[0003] Current overvoltage protection technology has deficiencies in dealing with such problems. For example, when the module loop adjustment speed is fast, the bus voltage will oscillate around the overvoltage value. This oscillation cannot effectively achieve the protection function. CONTENT OF THE UTILITY MODEL

[0004] Embodiments of the present disclosure provide a hysteresis overvoltage protection circuit to solve the problem of bus voltage oscillating around the overvoltage value.

[0005] Embodiments of the present disclosure provide a hysteresis overvoltage protection circuit, comprising: a first overvoltage detection module, a second overvoltage detection module and a main control module;

[0006] The first overvoltage detection module and the second overvoltage detection module are connected with the main control module;

[0007] The first overvoltage detection module is used for detecting a positive bus voltage, and the second overvoltage detection module is used for detecting a negative bus voltage;

[0008] The first overvoltage detection module comprises a first comparison circuit and a first hysteresis circuit;

[0009] The second overvoltage detection module comprises a second comparison circuit and a second hysteresis circuit;

[0010] A first end of the first comparison circuit is used for connecting a positive bus, a second end of the first comparison circuit is connected with the first end of the first comparison circuit through the first hysteresis circuit, and a third end of the first comparison circuit is connected with the main control module;

[0011] A first end of the second comparison circuit is used for connecting a negative bus, a second end of the second comparison circuit is connected with the first end of the second comparison circuit through the second hysteresis circuit, and a third end of the second comparison circuit is connected with the main control module.

[0012] In an example embodiment of the present disclosure, the first overvoltage detection module further comprises a first sampling circuit;

[0013] The second overvoltage detection module further comprises a second sampling circuit;

[0014] The first end of the first sampling circuit is connected to the positive bus, and the second end of the first sampling circuit is connected to the first end of the first comparison circuit;

[0015] The first end of the second sampling circuit is connected to the negative bus, and the second end of the second sampling circuit is connected to the first end of the second comparison circuit.

[0016] In an example embodiment of the present disclosure, the circuit structures of the first comparison circuit and the second comparison circuit are the same;

[0017] The first comparison circuit comprises a resistor R10, a resistor R11, an operational amplifier U1C, and a diode D10;

[0018] The first end of the resistor R10 is connected to the positive bus, the second end of the resistor R10 is grounded through the resistor R11, the second end of the resistor R10 is connected to the non-inverting input terminal of the operational amplifier U1C, the inverting input terminal of the operational amplifier U1C is connected to a reference voltage, the output terminal of the operational amplifier U1C is connected to the first return difference circuit, the output terminal of the operational amplifier U1C is connected to the anode of the diode D10, and the cathode of the diode D10 is connected to the master control module.

[0019] In an example embodiment of the present disclosure, the circuit structures of the first return difference circuit and the second return difference circuit are the same;

[0020] The first return difference circuit comprises a resistor R1 and a diode D11;

[0021] The first end of the resistor R1 is connected to the second end of the first comparison circuit, the second end of the resistor R1 is connected to the anode of the diode D11, and the cathode of the diode D11 is connected to the first end of the first comparison circuit.

[0022] In an example embodiment of the present disclosure, the circuit structures of the first sampling circuit and the second sampling circuit are the same;

[0023] The first sampling circuit comprises a resistor R9, a resistor R18, a resistor R2, an operational amplifier U1D, and a resistor R19;

[0024] The first end of the resistor R9 is connected to the positive bus, the second end of the resistor R9 is connected to the non-inverting input of the operational amplifier U1D, the second end of the resistor R9 is grounded through the resistor R2, the inverting input of the operational amplifier U1D is connected to the zero line through the resistor R18, the output of the operational amplifier U1D is connected to the inverting input of the operational amplifier U1D through the resistor R19, and the output of the operational amplifier U1D is connected to the input of the first comparison circuit.

[0025] In an exemplary embodiment of the present disclosure, further comprising: a reference voltage circuit for generating a reference voltage;

[0026] The reference voltage circuit comprises a resistor R22, a resistor R24 and a capacitor C2.

[0027] The first end of the resistor R22 is connected to the first power supply, the second end of the resistor R22 is grounded through the resistor R24, the capacitor C2 is connected in parallel with the resistor R24, and the second end of the resistor R22 is used to output the reference voltage.

[0028] In an exemplary embodiment of the present disclosure, further comprising: a fault clearing circuit;

[0029] The fault clearing circuit comprises a resistor R23, a resistor R25, a transistor Q1, a resistor R21, a diode D12 and a diode D13.

[0030] The first end of the resistor R23 is connected to the master control module, the second end of the resistor R23 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the second power supply through the resistor R21, the collector of the transistor Q1 is respectively connected to the cathode of the diode D12 and the diode D13, the anode of the diode D12 is connected to the first end of the first comparison circuit, and the anode of the diode D13 is connected to the first end of the second comparison circuit.

[0031] The emitter of the transistor Q1 is connected to the base of the transistor Q1 through the resistor R25, and the emitter of the transistor Q1 is grounded.

[0032] The back difference overvoltage protection circuit provided by the embodiment of the present disclosure has the beneficial effects that: the first overvoltage detection module detects the positive bus voltage, the second overvoltage detection module detects the negative bus voltage, and both are connected with the main control module, thereby realizing effective monitoring and information transmission of the bus voltage. The first comparison circuit in the first overvoltage detection module can obtain the real-time voltage of the positive bus as a judgment basis, cooperate with the first back difference circuit, notify the main control module to execute the protection such as envelope when the positive bus voltage reaches the overvoltage protection value, and use the back difference characteristic, only when the voltage is lower than the back difference value, it is determined that the overvoltage is removed, thereby avoiding voltage oscillation, ensuring the loop adjustment speed and the stability of the module. The second overvoltage detection module is the same. The main control module accurately judges the overvoltage removal opportunity according to the back difference condition, ensures that the energy storage module can quickly protect and stably recover normal operation when facing the bus overvoltage, and avoids damage of components and system hazards caused by overvoltage. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative labor.

[0034] Figure 1 is a structural block diagram of the back difference overvoltage protection circuit provided by the embodiment of the present disclosure;

[0035] Figure 2 is a circuit diagram of the back difference overvoltage protection circuit provided by the embodiment of the present disclosure. DETAILED DESCRIPTION

[0036] In order to make the personnel in the technical field better understand the present scheme, the technical solutions in the embodiments of the present scheme will be clearly described below in combination with the drawings in the embodiments of the present scheme. Obviously, the described embodiments are only some of the embodiments of the present scheme, not all. Based on the embodiments in the present scheme, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present scheme.

[0037] The terms "include", and other any variations thereof, in the specification and claims of the present scheme and the above-mentioned drawings, refer to "include but not limited to", and are intended to cover non-exclusive inclusion, and are not limited to the examples listed in the text. In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order.

[0038] The implementation of the present disclosure will be described in detail below in combination with specific drawings:

[0039] Figure 1A structural schematic diagram of a return difference overvoltage protection circuit is provided for the embodiments of the present disclosure. Referring to Figure 1 The return difference overvoltage protection circuit includes a first overvoltage detection module, a second overvoltage detection module, and a main control module. The first overvoltage detection module and the second overvoltage detection module are connected to the main control module. The first overvoltage detection module is used to detect the positive bus voltage, and the second overvoltage detection module is used to detect the negative bus voltage. The first overvoltage detection module includes a first comparison circuit and a first return difference circuit. The second overvoltage detection module includes a second comparison circuit and a second return difference circuit. The first end of the first comparison circuit is used to connect the positive bus, the second end of the first comparison circuit is connected to the first end of the first comparison circuit through the first return difference circuit, and the third end of the first comparison circuit is connected to the main control module. The first end of the second comparison circuit is used to connect the negative bus, the second end of the second comparison circuit is connected to the first end of the second comparison circuit through the second return difference circuit, and the third end of the second comparison circuit is connected to the main control module.

[0040] In the present embodiment, the return difference overvoltage protection circuit is mainly composed of a first overvoltage detection module, a second overvoltage detection module, and a main control module. The first overvoltage detection module is responsible for detecting the positive bus voltage, and the second overvoltage detection module is responsible for detecting the negative bus voltage. Both of the overvoltage detection modules are connected to the main control module to transmit the detected voltage information to the main control module for subsequent judgment and control operations.

[0041] The first comparison circuit is used to obtain the real-time voltage value of the positive bus. This real-time voltage value will be the basis for the subsequent comparison and judgment. For example, when the circuit is running normally, the positive bus voltage is within a reasonable set interval, and the first comparison circuit can continuously monitor the change of this voltage. The second end is connected to the first end of the first comparison circuit through the first return difference circuit. This connection constitutes a key part of the return difference characteristic. The return difference circuit will feed back a corresponding voltage signal to the comparison circuit based on the current voltage and the set return difference parameters. When the first comparison circuit compares the positive bus voltage with the reference voltage (a voltage value used for comparison and judgment formed by the return difference circuit and other factors), if it is determined that the positive bus voltage has reached the set overvoltage condition, it can send a corresponding signal to the main control module to notify the main control module that the positive bus has an overvoltage condition.

[0042] The first back-difference circuit is used to introduce back-difference characteristics for overvoltage detection. When the positive bus voltage rises and reaches a set overvoltage protection value (for example, the set positive bus overvoltage protection value is V1), the first comparison circuit detects this situation and sends a signal to the main control module, and the main control module performs a protection operation such as envelope closing, so that the bus voltage begins to drop. Without back-difference, in the case of fast module loop adjustment speed, once the bus voltage drops to close to V1, the circuit may misjudge that the bus voltage has returned to normal and restart the related operation, and such repeated operations will cause the voltage to oscillate around V1. With the first back-difference circuit, the overvoltage condition will only be determined to be removed when the positive bus voltage drops below a set back-difference value (for example, V2, and V2

[0043] In the present embodiment, the second overvoltage detection module includes a second comparison circuit and a second back-difference circuit, and the working principles of the second comparison circuit and the second back-difference circuit are the same as those of the first comparison circuit and the first back-difference circuit, which will not be described in detail here.

[0044] The main control module receives overvoltage signals sent from the first overvoltage detection module and the second overvoltage detection module. Once the relevant signals of positive bus or negative bus overvoltage are received, the main control module will start the corresponding protection action, such as performing an envelope closing operation, to prevent the circuit from continuing to operate in the original state, so that the bus voltage begins to drop, avoiding overvoltage damage to the bus capacitor and IGBT elements. In addition, the main control module will determine when the overvoltage condition is truly removed according to the back-difference conditions set by the back-difference circuits of the two overvoltage detection modules, and then decide when to let the module return to normal operation, so as to ensure that the entire energy storage module can quickly and effectively implement protection when facing bus overvoltage conditions, and stably return to the normal working state, avoiding harm to the entire system caused by overvoltage and subsequent unstable conditions.

[0045] From the above, the embodiment can detect the positive bus voltage by the first overvoltage detection module, detect the negative bus voltage by the second overvoltage detection module, and be connected with the main control module to realize effective monitoring and information transmission of the bus voltage. The first comparison circuit in the first overvoltage detection module can obtain the real-time voltage of the positive bus as the basis for judgment, cooperate with the first back difference circuit, and notify the main control module to execute the protection such as envelope when the positive bus voltage reaches the overvoltage protection value. Moreover, only when the voltage drops below the back difference value, the overvoltage is determined to be removed, which avoids voltage oscillation and ensures the loop adjustment speed and module stability. The second overvoltage detection module is the same. The main control module accurately judges the overvoltage removal opportunity according to the back difference condition, ensures that the energy storage module can quickly protect and stably recover normal operation when facing bus overvoltage, and avoids component overvoltage damage and system hazards.

[0046] As shown in Figure 1 In an embodiment of the present disclosure, the first overvoltage detection module further comprises a first sampling circuit, and the second overvoltage detection module further comprises a second sampling circuit. The first end of the first sampling circuit is used for connecting the positive bus, and the second end of the first sampling circuit is connected to the first end of the first comparison circuit. The first end of the second sampling circuit is used for connecting the negative bus, and the second end of the second sampling circuit is connected to the first end of the second comparison circuit.

[0047] In the embodiment, the first sampling circuit and the second sampling circuit are used to adjust the proportion and output the buffer.

[0048] The first end of the first sampling circuit can obtain the voltage signal of the positive bus. The second end thereof is connected to the first end of the first comparison circuit, so as to transmit the collected positive bus voltage information to the first comparison circuit.

[0049] In actual application, the positive bus voltage has a high amplitude or a specific voltage range, and the first sampling circuit can scale the positive bus voltage according to a certain proportion. For example, if the positive bus voltage is too high, direct input into the comparison circuit may exceed the processing range of the comparison circuit or affect the comparison accuracy. Through the proportional adjustment function of the sampling circuit, the voltage is adjusted to an appropriate level, so that the first comparison circuit can accurately compare and judge based on the adjusted voltage value and the reference voltage (formed by the first back difference circuit and the like).

[0050] The positive bus voltage may fluctuate or change rapidly, and the first sampling circuit as a buffer link can smooth the change of the voltage signal to a certain extent. This helps to avoid interference to the first comparison circuit caused by instantaneous mutation of the voltage, makes the voltage signal received by the first comparison circuit more stable and reliable, and further ensures the accuracy and stability of overvoltage detection.

[0051] In the embodiment, the second sampling circuit and the first sampling circuit have the same working principle, which will not be described in detail here.

[0052] From the above, the first sampling circuit and the second sampling circuit are connected to the positive bus and the negative bus respectively and the corresponding comparison circuit, which can play the role of adjusting the proportion and output buffering. For the positive bus voltage and the negative bus voltage with high amplitude or in a specific range, the sampling circuit can scale in proportion, so that the voltage is in the appropriate processing range of the comparison circuit, guarantees the comparison accuracy, and is beneficial to the reference voltage formed by the comparison with the differential circuit. At the same time, they can buffer the fluctuation and rapid change of the voltage, avoid the interference of instantaneous mutation on the comparison circuit, and enhance the accuracy and stability of the overvoltage detection.

[0053] As shown in Figure 2 , in an embodiment of the present disclosure, the circuit structures of the first comparison circuit and the second comparison circuit are the same; the first comparison circuit comprises: a resistor R10, a resistor R11, an operational amplifier U1C, and a diode D10; the first end of the resistor R10 is used for connecting the positive bus, the second end of the resistor R10 is grounded through the resistor R11, the second end of the resistor R10 is connected to the non-inverting input end of the operational amplifier U1C, the inverting input end of the operational amplifier U1C is connected to the reference voltage, the output end of the operational amplifier U1C is connected to the first differential circuit, the output end of the operational amplifier U1C is connected to the anode of the diode D10, and the cathode of the diode D10 is connected to the main control module.

[0054] In the embodiment, the resistor R10, the resistor R11, the operational amplifier U1C, and the diode D10 constitute the first comparison circuit (hysteresis comparator), and the output end outputs through the D10, as shown in Figure 2 , the output results of the operational amplifier U1C and the operational amplifier U1B are in an or relationship, mainly providing the differential voltage for overvoltage protection and protection results, and when the output of the operational amplifier U1C or the operational amplifier U1B is high, overvoltage protection is performed, and when the output is low, the circuit is normal and no operation is performed.

[0055] As shown in Figure 2 , the resistor R35, the resistor R45, the operational amplifier U1B, and the diode D6 constitute the second comparison circuit (hysteresis comparator), and the working principle of the second comparison circuit and the first comparison circuit is the same, which will not be described in detail here.

[0056] From the above, in the embodiment, the positive bus, the ground, and the reference voltage are connected reasonably, which can accurately compare the positive bus voltage with the reference voltage. The output end is connected to the main control module through the diode D10, and the output of the operational amplifier U1B is in an or relationship, and when the output of the two is high, overvoltage protection is triggered, and when the output is low, the circuit is normal. Thus, a reliable differential voltage and protection result judgment mechanism are provided for overvoltage protection, which effectively guarantees the safe and stable operation of the circuit.

[0057] As Figure 2 shown, in an embodiment of the present disclosure, the circuit structures of the first and second return difference circuits are the same; the first return difference circuit comprises a resistor R1 and a diode D11; a first end of the resistor R1 is connected to a second end of the first comparison circuit, a second end of the resistor R1 is connected to an anode of the diode D11, and a cathode of the diode D11 is connected to a first end of the first comparison circuit.

[0058] In the embodiment, when the voltage at the in-phase input end of the operational amplifier U1C is lower than the reference voltage, the operational amplifier U1C outputs a low level, that is, the positive bus is normal; when the voltage at the in-phase input end of the operational amplifier U1C is higher than the reference voltage, the operational amplifier U1C outputs a high level, the positive bus is overvoltage, and a protection action is performed; after the operational amplifier U1C outputs a high level, the output end (pin 8) of the operational amplifier U1C is connected to the in-phase input end of pin 8 through the resistor R1 and the diode D2, so as to further raise the voltage at the in-phase input end, and thus the voltage at the positive bus needs to be lowered to a certain extent to make the voltage at the in-phase input end of the operational amplifier U1C lower than the reference voltage, thereby realizing overvoltage return difference protection.

[0059] As can be seen from the above, when the operational amplifier U1C judges the voltage at the positive bus, the output is a low level under normal voltage, and once the positive bus is overvoltage, the output is a high level and a protection action is performed. Moreover, after the operational amplifier U1C outputs a high level, the voltage at the in-phase input end can be further raised through the resistor R1 and the diode D11, so that only when the voltage at the positive bus is lowered to a certain extent, the voltage at the in-phase input end of the operational amplifier U1C is lower than the reference voltage, thereby effectively realizing overvoltage return difference protection and avoiding frequent misjudgments caused by voltage fluctuations near the critical value, and ensuring stable operation of the circuit.

[0060] In the embodiment, the working principles of the first and second return difference circuits are the same, and thus will not be described herein.

[0061] As Figure 2 shown, in an embodiment of the present disclosure, the circuit structures of the first and second sampling circuits are the same; the first sampling circuit comprises a resistor R9, a resistor R18, a resistor R2, an operational amplifier U1D and a resistor R19; a first end of the resistor R9 is used for connecting the positive bus, a second end of the resistor R9 is connected to the in-phase input end of the operational amplifier U1D, the second end of the resistor R9 is connected to the ground through the resistor R2, the inverting input end of the operational amplifier U1D is connected to the zero line through the resistor R18, the output end of the operational amplifier U1D is connected to the inverting input end of the operational amplifier U1D through the resistor R19, and the output end of the operational amplifier U1D is connected to the input end of the first comparison circuit.

[0062] In the embodiment, the resistor R9, the resistor R18, the resistor R2, the operational amplifier U1D and the resistor R19 constitute a differential sampling circuit, which plays a role of adjusting proportion and output buffering.

[0063] In the first sampling circuit, one end of resistor R9 is connected to the positive bus to obtain a voltage signal, the second end of resistor R9 is connected to the non-inverting input terminal of operational amplifier U1D and grounded through resistor R2, and the inverting input terminal of operational amplifier U1D is connected to the zero line through resistor R18, so that a differential input form is formed. This connection mode can process the difference signal between the positive bus voltage and the zero line voltage by using the differential principle. By reasonably selecting the values of resistors R9, R18 and R2, the voltage ratio input to operational amplifier U1D can be changed. For example, according to the circuit design requirements, the resistance values of these resistors are adjusted, and the positive bus voltage with a higher amplitude is scaled by a certain ratio, so that the voltage signal output subsequently is suitable for the first comparison circuit to process. The output end of operational amplifier U1D is connected to the inverting input terminal of itself through resistor R19, forming a negative feedback loop. When the positive bus voltage fluctuates, this negative feedback structure can make the output of operational amplifier U1D relatively stable. Because the negative feedback has the function of suppressing changes, it can buffer the instantaneous mutation or rapid change of the voltage, so as to output a smooth and stable voltage to the first comparison circuit, avoiding the interference of voltage fluctuation on the comparison circuit.

[0064] In this embodiment, the working principles of the first sampling circuit and the second sampling circuit are the same, and will not be described here.

[0065] As shown in FIG. 1, Figure 2 As shown in FIG. 1,

[0066] In this embodiment, according to the series resistance voltage division principle, after the power supply voltage passes through the series connection of resistor R22 and resistor R24, a specific voltage value will be generated at the connection node of resistor R22 and resistor R24 (that is, the second end of resistor R22), which is the reference voltage output by the reference voltage circuit. The capacitor C2 is connected in parallel with the resistor R24, which mainly plays a filtering role. The reference voltage output at the second end of resistor R22 is smoother and more stable, so as to ensure that the subsequent circuit (such as a comparison circuit) which compares and judges by taking the reference voltage as a reference can work more accurately, avoiding misjudgment and other situations caused by unstable reference voltage.

[0067] As shown in FIG. 1, Figure 2As shown, in an embodiment of the present disclosure, further comprising: a fault clearing circuit; the fault clearing circuit comprises: a resistor R23, a resistor R25, a triode Q1, a resistor R21, a diode D12 and a diode D13; a first end of the resistor R23 is connected to the master control module, a second end of the resistor R23 is connected to a base of the triode Q1, a collector of the triode Q1 is connected to a second power supply through the resistor R21, the collector of the triode Q1 is connected to cathodes of the diode D12 and the diode D13 respectively, an anode of the diode D12 is connected to a first end of the first comparison circuit, and an anode of the diode D13 is connected to a first end of the second comparison circuit; an emitter of the triode Q1 is connected to the base of the triode Q1 through the resistor R25, and the emitter of the triode Q1 is grounded.

[0068] In the embodiment, the resistor R23, the resistor R25, the triode Q1, the resistor R21, the diode D12 and the diode D13 constitute the fault clearing circuit, the collector of the triode Q1 is connected to the non-inverting input terminal of the operational amplifier U1C and the operational amplifier U1B through the diode D12 and the diode D13 respectively, when the triode Q1 is turned on, the non-inverting input terminals of the operational amplifier U1C and the operational amplifier U1B are pulled to low level, at this time, no matter what state the protection circuit is in, the circuit will not alarm. When the triode Q1 is turned off, the collector of the triode Q1 is high level, and the circuit has no effect.

[0069] From the above, when the triode Q1 is turned on, the non-inverting input terminals of the operational amplifier U1C and the operational amplifier U1B are pulled to low level through the diode D12 and the diode D13, so no matter what state the protection circuit is in, the circuit will not alarm, which is very practical when manual clearing of faults or stopping the alarm function under certain conditions is needed, and can effectively avoid unnecessary alarm interference. When the triode Q1 is turned off, the collector of the triode Q1 is high level, which has no effect on the normal operation of the circuit, and ensures the integrity and stability of the circuit function.

[0070] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than limit them; although the foregoing embodiments of the present disclosure have been described in detail, those skilled in the art should understand: the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A backoff overvoltage protection circuit, characterized by, include: The system comprises a first overvoltage detection module, a second overvoltage detection module, and a main control module. Both the first overvoltage detection module and the second overvoltage detection module are connected to the main control module; The first overvoltage detection module is used to detect the positive bus voltage, and the second overvoltage detection module is used to detect the negative bus voltage. The first overvoltage detection module includes: a first comparison circuit and a first hysteresis circuit; The second overvoltage detection module includes: a second comparison circuit and a second hysteresis circuit; The first terminal of the first comparison circuit is used to connect to the positive bus, the second terminal of the first comparison circuit is connected to the first terminal of the first comparison circuit through the first hysteresis circuit, and the third terminal of the first comparison circuit is connected to the main control module. The first terminal of the second comparison circuit is used to connect to the negative bus, the second terminal of the second comparison circuit is connected to the first terminal of the second comparison circuit through the second hysteresis circuit, and the third terminal of the second comparison circuit is connected to the main control module.

2. The hysteresis overvoltage protection circuit as described in claim 1, characterized in that, The first overvoltage detection module further includes: a first sampling circuit; The second overvoltage detection module further includes: a second sampling circuit; The first terminal of the first sampling circuit is used to connect to the positive bus, and the second terminal of the first sampling circuit is connected to the first terminal of the first comparison circuit. The first terminal of the second sampling circuit is used to connect to the negative bus, and the second terminal of the second sampling circuit is connected to the first terminal of the second comparison circuit.

3. A differential voltage overvoltage protection circuit as defined in claim 1, wherein The first comparison circuit and the second comparison circuit have the same circuit structure; The first comparator circuit includes: resistor R10, resistor R11, operational amplifier U1C, and diode D10; The first end of resistor R10 is used to connect to the positive bus, the second end of resistor R10 is grounded through resistor R11, the second end of resistor R10 is connected to the non-inverting input of operational amplifier U1C, the inverting input of operational amplifier U1C is connected to the reference voltage, the output of operational amplifier U1C is connected to the first hysteresis circuit, the output of operational amplifier U1C is connected to the anode of diode D10, and the cathode of diode D10 is connected to the main control module.

4. A differential voltage overvoltage protection circuit as defined in claim 1, wherein The first hysteresis circuit and the second hysteresis circuit have the same circuit structure; The first hysteresis circuit includes a resistor R1 and a diode D11; The first end of the resistor R1 is connected to the second end of the first comparator circuit, the second end of the resistor R1 is connected to the anode of the diode D11, and the cathode of the diode D11 is connected to the first end of the first comparator circuit.

5. A differential voltage overvoltage protection circuit as defined in claim 2, wherein The first sampling circuit and the second sampling circuit have the same circuit structure; The first sampling circuit includes: resistor R9, resistor R18, resistor R2, operational amplifier U1D, and resistor R19; The first end of the resistor R9 is connected to the positive bus, the second end of the resistor R9 is connected to the non-inverting input of the operational amplifier U1D, the second end of the resistor R9 is grounded through the resistor R2, the inverting input of the operational amplifier U1D is connected to the zero line through the resistor R18, the output of the operational amplifier U1D is connected to the inverting input of the operational amplifier U1D through the resistor R19, and the output of the operational amplifier U1D is connected to the input of the first comparison circuit.

6. A differential voltage overvoltage protection circuit as defined in claim 1, wherein Further comprising: a reference voltage circuit for generating a reference voltage; The reference voltage circuit comprises a resistor R22, a resistor R24 and a capacitor C2; The first end of the resistor R22 is connected to the first power supply, the second end of the resistor R22 is grounded through the resistor R24, the capacitor C2 is connected in parallel with the resistor R24, and the second end of the resistor R22 is used to output the reference voltage.

7. A differential voltage overvoltage protection circuit as defined in claim 1, wherein Further comprising: a fault clearing circuit; The fault clearing circuit comprises a resistor R23, a resistor R25, a transistor Q1, a resistor R21, a diode D12 and a diode D13; The first end of the resistor R23 is connected to the main control module, the second end of the resistor R23 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the second power supply through the resistor R21, the collector of the transistor Q1 is respectively connected to the cathode of the diode D12 and the diode D13, the anode of the diode D12 is connected to the first end of the first comparison circuit, and the anode of the diode D13 is connected to the first end of the second comparison circuit; The emitter of the transistor Q1 is connected to the base of the transistor Q1 through the resistor R25, and the emitter of the transistor Q1 is grounded.

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