IGBT overvoltage protection device and method

Abstract

The present invention relates to the technical field of high-voltage power transmission, and disclosed are an IGBT overvoltage protection device and method. The IGBT overvoltage protection device comprises: a controller, an overvoltage determination unit, a voltage collection unit, and a drive circuit. The voltage collection unit is used for collecting a voltage between a collector and an emitter of an IGBT; the overvoltage determination unit is used for comparing the collected voltage with a plurality of reference voltages and then outputting a plurality of overvoltage determination results; the drive circuit is used for controlling on / off of the IGBT on the basis of a drive signal; and the controller determines the current operation condition of the IGBT, then selects an overvoltage determination result corresponding to the current operation condition, and drives, on the basis of the overvoltage determination result, the drive circuit to perform overvoltage protection on the IGBT. According to the present invention, on the basis of the working condition of an IGBT, a voltage comparison result corresponding to said working condition is selected, and the IGBT is controlled to be turned on for a corresponding time period on the basis of the voltage comparison result, thereby implementing controllable and rapid overvoltage protection of the IGBT.

Description

IGBT overvoltage protection device and method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202410123496.5 and application date of January 29, 2024, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application in its entirety. Technical Field

[0003] The present invention relates to the technical field of high-voltage power transmission, and in particular to an IGBT overvoltage protection device and method. Background Art

[0004] Insulated Gate Bipolar Transistors (IGBTs) are core components for energy conversion and transmission, and are widely used in power electronics. During operation, IGBTs can experience collector-emitter overvoltages due to primary circuit faults or surge voltages during shutdown, ultimately leading to IGBT failure.

[0005] To address surge overvoltages that occur during IGBT turn-off, a common solution is to connect an RCD snubber circuit in parallel across the IGBT to absorb and clamp the overvoltage, or to employ soft shutdown or active clamping circuits to reduce the voltage spike at turn-off. However, in some high-voltage transmission applications, the design of a parallel snubber circuit is difficult due to primary circuit parameter requirements, or protection against busbar overvoltages caused by primary circuit faults is required. Therefore, a fast IGBT collector-emitter overvoltage protection method is needed to quickly turn on the IGBT when an overvoltage occurs at the collector-emitter terminal, thereby rapidly reducing the collector-emitter voltage. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to solve the problem that the prior art cannot provide overvoltage protection for the IGBT under different working states of the IGBT and its control circuit, thereby providing an IGBT overvoltage protection device and method.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides an IGBT overvoltage protection device, comprising: a controller, an overvoltage judgment unit, a voltage acquisition unit and a drive circuit, wherein the voltage acquisition unit is connected to the IGBT and is also connected to the controller and the overvoltage judgment unit, and is used to acquire the voltage between the collector and emitter of the IGBT and send the acquired voltage to the controller and the overvoltage judgment unit; the overvoltage judgment unit is connected to the controller and is used to compare the acquired voltage with multiple reference voltages and output multiple overvoltage judgment results to the controller; the drive circuit is connected to the controller and the gate of the IGBT and is used to control the on and off of the IGBT based on the drive signal sent by the controller; the controller is connected to the control system of the IGBT and obtains the working status of the control system; each reference voltage is equal to the normal working voltage of the IGBT under one operating condition; the controller judges the current operating condition of the IGBT based on the acquired voltage and the working status of the control system, selects the overvoltage judgment result corresponding to the current operating condition, and drives the drive circuit to perform overvoltage protection on the IGBT based on the overvoltage judgment result.

[0009] The IGBT overvoltage protection device provided by the present invention first stores the normal operating voltage of the IGBT under various working conditions as a reference voltage, compares the real-time voltage of the IGBT with multiple reference voltages, and outputs multiple comparison results. Then, the working condition of the IGBT is judged according to the real-time voltage of the IGBT and the working state of the control system, thereby selecting the overvoltage judgment result corresponding to the working condition, judging whether the IGBT is overvoltage under the current working condition, and thus performing rapid overvoltage protection on the IGBT. The overvoltage conditions of the IGBT under various working conditions can be monitored, and the protection range is comprehensive and the protection response speed is fast.

[0010] In an optional embodiment, the overvoltage judgment unit includes multiple voltage comparison circuits; each voltage comparison circuit inputs a sampled voltage and a reference voltage and is connected to a controller; the voltage comparison circuit is used to compare the sampled voltage with a reference voltage and output an overvoltage judgment result corresponding to the reference voltage.

[0011] The IGBT overvoltage protection device provided by the present invention sets different reference voltages according to different operating conditions of the IGBT, thereby improving the accuracy of overvoltage judgment under different operating conditions.

[0012] In an optional embodiment, the voltage comparison circuit includes: an operational amplifier, which inputs a sampled voltage and a reference voltage and is connected to a controller; the operational amplifier is used to compare the sampled voltage with a reference voltage and output an overvoltage judgment result corresponding to the reference voltage.

[0013] In an optional embodiment, the IGBT overvoltage protection device also includes: multiple reference voltage generating circuits; each reference voltage generating circuit is connected to a voltage comparison circuit; each reference voltage generating circuit is used to generate a reference voltage equal to the normal operating voltage of the IGBT under one operating condition.

[0014] In an optional embodiment, the IGBT overvoltage protection device further includes: a control system monitoring unit, which is connected to the control system and the controller, and is used to monitor the working status of the control system and send the working status of the control system to the controller.

[0015] The IGBT overvoltage protection device provided by the present invention can quickly obtain the working condition of the IGBT by obtaining the working state of the control system.

[0016] In an optional implementation, the IGBT overvoltage protection device further includes: a driving circuit configured to send the operating status of the IGBT to the controller.

[0017] In a second aspect, the present invention provides an IGBT overvoltage protection method, which is applied to the IGBT overvoltage protection device of the first aspect, and the method includes: a controller obtains the collected voltage of the IGBT, the working state of the control system, and multiple overvoltage judgment results generated by the overvoltage judgment unit; the controller judges the current operating condition of the IGBT based on the collected voltage and the working state of the control system; after the controller selects the overvoltage judgment result corresponding to the current operating condition of the IGBT, the controller drives the driving circuit to perform overvoltage protection on the IGBT based on the overvoltage judgment result.

[0018] The IGBT overvoltage protection method provided by the present invention first stores the normal operating voltage of the IGBT under various working conditions as a reference voltage, compares the real-time voltage of the IGBT with multiple reference voltages, and outputs multiple comparison results. Then, the working condition of the IGBT is judged according to the real-time voltage of the IGBT and the working state of the control system, thereby selecting the overvoltage judgment result corresponding to the working condition, judging whether the IGBT is overvoltage under the current working condition, and thus performing rapid overvoltage protection on the IGBT. The overvoltage conditions of the IGBT under various working conditions can be monitored, and the protection range is comprehensive and the protection response speed is fast.

[0019] In an optional embodiment, the process of the controller selecting the overvoltage judgment result corresponding to the current operating condition of the IGBT includes: the controller determines the standard operating voltage of the IGBT under the current operating condition; the controller selects a reference voltage that is the same as the standard operating voltage, and obtains the overvoltage judgment result output by the voltage comparison circuit under the action of the reference voltage.

[0020] In an optional embodiment, the process of driving the driving circuit to perform overvoltage protection on the IGBT based on the overvoltage judgment result includes: the controller determines whether overvoltage occurs in the IGBT under the current working conditions based on the overvoltage judgment result; if it is determined that overvoltage occurs, the controller controls the driving circuit to trigger the IGBT to turn on, thereby performing overvoltage protection on the IGBT; if it is determined that no overvoltage occurs, the controller controls the driving circuit to maintain the IGBT locked state.

[0021] In an optional embodiment, the process of the controller controlling the drive circuit to trigger the IGBT to turn on includes: after the controller obtains the triggering duration of the IGBT under the current working condition, the controller controls the drive circuit to trigger the IGBT to turn on according to the triggering duration.

[0022] The IGBT overvoltage protection method provided by the present invention controls the corresponding conduction time of the IGBT under corresponding working conditions according to different overvoltage judgment results. The overvoltage control means corresponds to the working conditions of the IGBT, and can accurately perform overvoltage protection on the IGBT. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] FIG1 is a composition diagram of a specific example of an IGBT overvoltage protection device according to an embodiment of the present invention;

[0025] FIG2 is a structural diagram of a specific circuit of an IGBT overvoltage protection device according to an embodiment of the present invention;

[0026] FIG3 is a flow chart of an IGBT overvoltage protection method according to an embodiment of the present invention;

[0027] FIG4 is an overvoltage protection logic diagram of an IGBT overvoltage protection method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components; wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0031] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] This embodiment provides an IGBT overvoltage protection device, as shown in Figure 1, including: a controller 1, an overvoltage judgment unit 2, a voltage acquisition unit 3 and a drive circuit 4. It should be noted that this embodiment is not limited to overvoltage protection for IGBTs, but can also be used for overvoltage protection of other power devices, which is not limited here.

[0033] As shown in FIG1 , the voltage acquisition unit 3 is connected to the IGBT, and is also connected to the controller 1 and the overvoltage judgment unit 2. It is used to collect the voltage between the collector and emitter of the IGBT and then collect the voltage V CE The overvoltage judgment unit 2 is connected to the controller 1 and is used to collect the voltage V CE After comparing with multiple reference voltages (Vref<1)~Vref(n)), multiple overvoltage judgment results are output. To controller 1; a drive circuit 4, which is connected to the controller 1 and the gate of the IGBT, and is used to control the on and off of the IGBT based on the drive signal sent by the controller 1; a controller 1, which is connected to the control system of the IGBT and obtains the working status of the control system.

[0034] In Figure 1, each reference voltage is equal to the normal working voltage of the IGBT under a certain operating condition; the controller 1 is based on the collected voltage V CE(i.e., IGBT emitter-collector voltage) and the working state of the control system, after judging the current operating condition of the IGBT, the overvoltage judgment result corresponding to the current operating condition is selected, and the driving circuit 4 is driven based on the overvoltage judgment result to perform overvoltage protection on the IGBT.

[0035] Specifically, in FIG1 , the voltage acquisition unit 3 acquires the collector-emitter voltage of the IGBT in real time and then acquires the voltage V CE The control system is used to control the IGBT operation according to the preset parameters. The controller 1 monitors the working state of the control system and collects the voltage V CE , the current operating condition of the IGBT can be determined, thereby obtaining the normal operating voltage of the IGBT under the current operating condition. At the same time, by testing the IGBT under various operating conditions, the normal operating voltage of the IGBT under each operating condition is stored as the reference voltage (Vref(1)~Vref(n)) in the overvoltage judgment unit 2. The overvoltage judgment unit 2 will receive the collected voltage V CE After comparing with each reference voltage (Vref(1) to Vref(n)), the overall overvoltage judgment result is output. To controller 1.

[0036] Specifically, in Figure 1, the controller 1 finds the normal operating voltage of the IGBT under the current operating condition of the IGBT, selects a reference voltage equal to the normal operating voltage, and obtains an overvoltage judgment result output based on the reference voltage. If it is identified that the IGBT is overvoltage-prone according to the overvoltage judgment result, the controller 1 drives the drive circuit 4 to perform corresponding overvoltage protection on the IGBT under the operating condition; if it is identified that the IGBT is not overvoltage-prone according to the overvoltage judgment result, the controller 1 does not send a drive signal to the drive circuit 4, so that the IGBT maintains the current working state.

[0037] For example, in FIG1 , if the selected reference voltage is Vref( 1 ), an overvoltage judgment result S( 1 ) output according to the reference voltage Vref( 1 ) is obtained, and whether an overvoltage occurs in the IGBT is judged according to the overvoltage judgment result S( 1 ).

[0038] For example, in FIG1 , the first reference value is the maximum withstand voltage of the IGBT specified by the manufacturer. The reference voltage Vref(1) of the first reference value can be generated by a voltage divider circuit, V ref (1)=0.85V CEmax The second reference value is the analog signal converted from the digital signal output by the FPGA by the DA chip. The FPGA calculates the rate of change of the voltage across the IGBT through the current bus current value: dV CE / dt=i / C, where dV CE / dt is the rate of change of IGBT collector-emitter voltage, i is the bus current value, and C is the equivalent capacitance value at both ends of IGBT. ref (2) = 0.8 V CEmax -td×dV CE / dt, determine the reference voltage Vref(2) of the second reference value taking into account the protection delay, where td is the delay time of the controller 1.

[0039] For example, in FIG1 , when the system is operating under normal conditions, Vref(1) is selected as the reference voltage. When the IGBT collector-emitter voltage exceeds this reference voltage, the IGBT is turned on for a fixed duration. When the controller 1 detects that the current bus current value exceeds a certain threshold, or the communication link between the controller 1 and the remote is disconnected, or the average value of the IGBT collector-emitter voltage in a short period of time exceeds 0.8 times the maximum withstand voltage of the IGBT, Vref(2) is selected as the reference voltage. When the IGBT collector-emitter voltage exceeds Vref(2), the IGBT is turned on. The on-time is determined by the current bus current and the operating status of the controller communication link.

[0040] Exemplarily, the overvoltage protection methods corresponding to different operating conditions of the IGBT include but are not limited to the corresponding overvoltage protection durations under different operating conditions.

[0041] Exemplarily, determining the IGBT operating condition includes processing IGBT collector-emitter voltage information and control system status information, and performing a logical judgment on the processing results. The processing of IGBT voltage information and control system status information includes, but is not limited to, calculating analog quantities such as the IGBT collector-emitter voltage change rate, IGBT junction temperature, and IGBT operating power consumption, as well as Boolean quantities such as determining whether the communication link with the remote controller is functioning properly and whether the local control system is functioning properly. The operating condition is determined based on the aforementioned processing results, and the judgment criteria include, but are not limited to, determining whether the analog quantity results exceed or fall below a set threshold, determining the Boolean quantity results, or performing a combined logical operation on the aforementioned determination results.

[0042] Exemplarily, the voltage acquisition method of the voltage acquisition unit includes but is not limited to using methods such as resistor voltage division, capacitor voltage division, resistor-capacitor voltage division, magnetic coupling, or AD conversion circuit.

[0043] The IGBT overvoltage protection device provided in this embodiment first stores the normal working voltage of the IGBT under various working conditions as a reference voltage, and compares the real-time voltage of the IGBT with multiple reference voltages and outputs multiple comparison results. It then judges the working condition of the IGBT based on the real-time voltage of the IGBT and the working state of the control system, thereby selecting the overvoltage judgment result corresponding to the working condition, and judging whether the IGBT is overvoltage under the current working condition, thereby performing rapid overvoltage protection on the IGBT. It can monitor the overvoltage conditions of the IGBT under various working conditions, with a comprehensive protection range and a fast protection response speed.

[0044] In some optional embodiments, the overvoltage judgment unit includes multiple voltage comparison circuits. As shown in FIG2 , the voltage comparison circuit is composed of an operational amplifier U, whose input is the collected voltage V CE And a reference voltage Vref(i), and connected to the controller 1; the operational amplifier U is used to collect the voltage V CE After comparison with a reference voltage Vref(i), an overvoltage judgment result S(i) corresponding to the reference voltage Vref(i) is output, where i is any number from 1 to n, and n is the number of operating conditions of the IGBT.

[0045] In Figure 2, the IGBT overvoltage protection device also includes: multiple reference voltage generation circuits (#1-#n); each reference voltage generation circuit is connected to an operational amplifier U; each reference voltage generation circuit is used to generate a reference voltage equal to the normal operating voltage of the IGBT under a specific operating condition. Controller 1 is also used to obtain the triggering duration of the IGBT under the current operating condition and control drive circuit 4 to trigger the IGBT to conduct according to the triggering duration.

[0046] Specifically, in FIG2 , the reference voltage generated by each reference voltage generating circuit (#1 to #n) is adjustable, and the output reference voltage can be set according to different operating conditions of different IGBTs, which is highly flexible and can be used to generate a stable DC reference voltage.

[0047] For example, in FIG2 , each operational amplifier U is used to convert the reference voltage Vref(i) at the two input terminals into the sampling voltage V CE Compare; when the sampling voltage V CE When the voltage V is greater than or equal to the reference voltage Vref(i), the high-level overvoltage judgment result S(i) is output. The controller 1 recognizes that the IGBT is overvoltage based on the high-level overvoltage judgment result S(i). At the same time, the controller 1 obtains the corresponding triggering time according to the current working condition of the IGBT, and controls the driving circuit 4 to trigger the IGBT to turn on according to the triggering time to perform overvoltage protection. When the collected voltage V CEWhen it is less than the reference voltage Vref(i), a low-level overvoltage judgment result S(i) is output. Based on the low-level overvoltage judgment result S(i), the controller 1 recognizes that the IGBT is not overvoltage-prone. The controller 1 does not send a driving signal to the driving circuit 4, so that the IGBT maintains its current working state.

[0048] Illustratively, the form of the overvoltage determination result includes, but is not limited to, a level signal, a differential signal, a code complying with a specific communication protocol, and the like.

[0049] Exemplarily, the types of controllers include but are not limited to processors such as ARM, FPGA, CPLD, DSP, and microcomputer.

[0050] Exemplarily, the circuit form of the reference voltage generating circuit includes but is not limited to a voltage divider circuit composed of passive components such as fixed or adjustable resistors, or a D / A conversion circuit, or a voltage-regulated power supply circuit with a fully controlled power electronic switch, or a low dropout regulator (LDO), etc.

[0051] In some optional embodiments, as shown in FIG2 , the IGBT overvoltage protection device further includes: a control system monitoring unit 5 connected to the control system and the controller 1, configured to monitor the operating state of the control system and send the operating state of the control system to the controller 1. The drive circuit is configured to send the operating state of the IGBT to the controller.

[0052] For example, the drive circuit can execute the commands of the controller, generate reliable and accurate trigger pulses for turning on / off the IGBT, and can also transmit the working status information of the IGBT back to the controller. The returned status information includes but is not limited to gate power failure, turn-on failure, turn-off failure, etc.

[0053] Exemplarily, the monitoring content of the system monitoring unit includes but is not limited to the power status of the local or remote control system, the operating status of each control unit of the local or remote control system, the communication status within the local or remote control system, the communication status between the local and remote control systems, the primary system voltage or current parameters sent to the controller by the remote control system via the communication link, etc.

[0054] This embodiment provides an IGBT overvoltage protection method, which is applied to the IGBT overvoltage protection device of the above embodiment and any optional implementation manner thereof, as shown in FIG3 , and includes:

[0055] Step S1: The controller obtains the collected voltage of the IGBT, the working state of the control system, and multiple overvoltage judgment results generated by the overvoltage judgment unit.

[0056] Specifically, referring to FIG2 , the process of generating multiple overvoltage judgment results includes: (1) the controller 1 judges the standard operating voltage of the IGBT under the current operating conditions; (2) the controller 1 selects a reference voltage that is the same as the standard operating voltage, and obtains the overvoltage judgment result output by the voltage comparison circuit under the action of the reference voltage.

[0057] Step S2: The controller determines the current operating condition of the IGBT based on the collected voltage and the operating status of the control system.

[0058] Step S3: After the controller selects the overvoltage judgment result corresponding to the current operating condition of the IGBT, it drives the driving circuit to perform overvoltage protection on the IGBT based on the overvoltage judgment result.

[0059] Specifically, referring to FIG2 , the process of overvoltage protection includes: (1) the controller 1 determines whether an overvoltage occurs in the IGBT under the current working condition based on the overvoltage judgment result; (2) if it is determined that an overvoltage occurs, the controller 1 controls the drive circuit 4 to trigger the IGBT to turn on, thereby performing overvoltage protection on the IGBT; (3) if it is determined that no overvoltage occurs, the controller 1 controls the drive circuit 4 to maintain the IGBT locked state.

[0060] For example, FIG4 is a logic diagram of the overvoltage protection method. The overvoltage judgment, protection method and protection logic involved in this embodiment are consistent with those described in the above embodiment and any optional implementation manner thereof, and are not repeated here.

[0061] The IGBT overvoltage protection method provided in this embodiment first stores the normal operating voltage of the IGBT under various working conditions as a reference voltage, compares the real-time voltage of the IGBT with multiple reference voltages, and outputs multiple comparison results. Then, the working condition of the IGBT is judged according to the real-time voltage of the IGBT and the working state of the control system, thereby selecting the overvoltage judgment result corresponding to the working condition, and judging whether the IGBT is overvoltage under the current working condition, thereby performing rapid overvoltage protection on the IGBT. The overvoltage conditions of the IGBT under various working conditions can be monitored, and the protection range is comprehensive and the protection response speed is fast.

[0062] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An IGBT overvoltage protection device, comprising: Controller, overvoltage judgment unit, voltage acquisition unit and drive circuit, wherein, a voltage acquisition unit connected to the IGBT, and further connected to the controller and the overvoltage judgment unit, configured to acquire the voltage between the collector and emitter of the IGBT and send the acquired voltage to the controller and the overvoltage judgment unit; an overvoltage judgment unit connected to the controller, configured to compare the collected voltage with a plurality of reference voltages and output a plurality of overvoltage judgment results to the controller; a drive circuit connected to the controller and the gate of the IGBT, and configured to control the on and off of the IGBT based on a drive signal sent by the controller; A controller connected to the IGBT control system and acquiring the operating status of the control system; Each of the reference voltages is respectively equal to the normal operating voltage of the IGBT under one operating condition; The controller determines the current operating condition of the IGBT based on the collected voltage and the working state of the control system, selects an overvoltage judgment result corresponding to the current operating condition, and drives the drive circuit to perform overvoltage protection on the IGBT based on the overvoltage judgment result.

2. The IGBT overvoltage protection device according to claim 1, wherein: The overvoltage judgment unit includes a plurality of voltage comparison circuits; Each of the voltage comparison circuits inputs a sampled voltage and a reference voltage and is connected to the controller; The voltage comparison circuit is used to compare the collected voltage with a reference voltage and output an overvoltage judgment result corresponding to the reference voltage.

3. The IGBT overvoltage protection device according to claim 2, wherein: The voltage comparison circuit comprises: An operational amplifier is input with a sampled voltage and a reference voltage and is connected to the controller; the operational amplifier is used to compare the sampled voltage with a reference voltage and output an overvoltage judgment result corresponding to the reference voltage.

4. The IGBT overvoltage protection device according to claim 2, wherein: Also included are: a plurality of reference voltage generating circuits; Each of the reference voltage generating circuits is connected to one of the voltage comparison circuits; each of the reference voltage generating circuits is used to generate a reference voltage that is equal to the normal operating voltage of the IGBT under one operating condition.

5. The IGBT overvoltage protection device according to claim 1, wherein: Also includes: A control system monitoring unit is connected to the control system and the controller, and is used to monitor the working status of the control system and send the working status of the control system to the controller.

6. The IGBT overvoltage protection device according to claim 1, wherein: Also includes: The driving circuit is used to send the working status of the IGBT to the controller.

7. An IGBT overvoltage protection method, the method being applied to the IGBT overvoltage protection device according to any one of claims 1 to 6, the method comprising: The controller obtains the collected voltage of the IGBT, the working state of the control system and multiple overvoltage judgment results generated by the overvoltage judgment unit; The controller determines the current operating condition of the IGBT based on the collected voltage and the operating state of the control system; After the controller selects the overvoltage judgment result corresponding to the current operating condition of the IGBT, it drives the driving circuit to perform overvoltage protection on the IGBT based on the overvoltage judgment result.

8. The IGBT overvoltage protection method according to claim 7, wherein: The process of the controller selecting the overvoltage judgment result corresponding to the current operating condition of the IGBT includes: The controller determines the standard operating voltage of the IGBT under the current operating conditions; The controller selects a reference voltage that is the same as the standard operating voltage, and obtains an overvoltage judgment result output by the voltage comparison circuit under the action of the reference voltage.

9. The IGBT overvoltage protection method according to claim 7, wherein: The process of driving the driving circuit to perform overvoltage protection on the IGBT based on the overvoltage judgment result includes: The controller determines whether the IGBT is overvoltage-prone under the current working condition based on the overvoltage judgment result; If it is determined that an overvoltage occurs, the controller controls the drive circuit to trigger the IGBT to turn on, thereby performing overvoltage protection on the IGBT; If it is determined that no overvoltage occurs, the controller controls the drive circuit to maintain the IGBT locked state.

10. The IGBT overvoltage protection method according to claim 9, wherein: The process in which the controller controls the drive circuit to trigger the IGBT to turn on includes: After acquiring the triggering duration of the IGBT under the current working condition, the controller controls the driving circuit to trigger the IGBT to turn on according to the triggering duration.

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