Multi-IGBT parallel overvoltage detection circuit

Abstract

The invention relates to the technical field of semiconductors, in particular to a multi-IGBT parallel overvoltage detection circuit, which comprises a voltage acquisition module, a voltage analysis module and an overvoltage hardware protection module, wherein the voltage acquisition module is used for acquiring first voltage signals of positive direct current ends of a plurality of IGBTs which are connected in parallel; the voltage analysis module is used for analyzing and calculating the first voltage signal based on the driving protection requirement to obtain a calculated and analyzed second voltage signal; and the overvoltage hardware protection module is used for sending an overvoltage protection signal to the IGBT driving circuit under the condition that the second voltage signal meets the overvoltage protection requirement, so that the IGBT driving circuit adjusts the on-off states of the plurality of IGBTs according to the second voltage signal. By the adoption of the scheme, overvoltage suppression and feedback protection can be achieved when a plurality of IGBTs connected in parallel are driven.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a multi-IGBT parallel overvoltage detection circuit. Background Art

[0002] Insulate-Gate Bipolar Transistor (IGBT) combines the advantages of Giant Transistor (GTR) and Power MOSFET, has good characteristics, and is widely used. However, in the prior art, when driving multiple IGBTs connected in parallel, the overvoltage suppression and feedback protection of multiple IGBTs in parallel are not considered, resulting in frequent burnout of IGBT devices due to overvoltage. Summary of the invention

[0003] The present disclosure provides a multi-IGBT parallel overvoltage detection circuit, the main purpose of which is to achieve overvoltage suppression and feedback protection when driving multiple IGBTs connected in parallel.

[0004] According to one aspect of the present disclosure, a multi-IGBT parallel overvoltage detection circuit is provided, comprising: a voltage acquisition module, a voltage analysis module and an overvoltage hardware protection module; wherein,

[0005] The voltage acquisition module is used to acquire a first voltage signal of a positive DC terminal of a plurality of IGBTs connected in parallel;

[0006] The voltage analysis module is used to analyze and calculate the first voltage signal based on the driving protection requirement to obtain a second voltage signal after calculation and analysis;

[0007] The overvoltage hardware protection module is used to send an overvoltage protection signal to the IGBT drive circuit when the second voltage signal meets the overvoltage protection requirements, so that the IGBT drive circuit adjusts the on and off states of the multiple IGBTs according to the second voltage signal.

[0008] Optionally, in one embodiment of the present disclosure, the voltage analysis module includes a voltage acquisition unit, an intelligent control chip and a voltage logic output unit; wherein,

[0009] The voltage acquisition unit is used to convert the first voltage signal into a third voltage signal that meets the requirements of the intelligent control chip;

[0010] The intelligent control chip is used to analyze and calculate the third voltage signal based on the driving protection requirement to obtain a fourth voltage signal after calculation and analysis, wherein the fourth voltage signal is a digital signal;

[0011] The voltage logic output unit is used to convert the fourth voltage signal into an analog signal to obtain the second voltage signal.

[0012] Optionally, in an embodiment of the present disclosure, the voltage acquisition unit, the intelligent control chip and the voltage logic output unit are integrated in an intelligent voltage detection output logic control unit.

[0013] Optionally, in one embodiment of the present disclosure, the intelligent voltage detection output logic control unit is a programmable voltage acquisition processing controller.

[0014] Optionally, in an embodiment of the present disclosure, the voltage acquisition module includes N first resistors, where N is a positive integer; wherein,

[0015] The first end of the first first resistor is grounded, the second end of the first first resistor is connected to the first voltage input terminal of the voltage analysis module and the first end of the second first resistor, the first end of the Nth first resistor is connected to the second end of the N-1th first resistor and the N-1th voltage input terminal of the voltage analysis module, and the second end of the Nth first resistor is connected to the Nth voltage input terminal of the voltage analysis module and the positive DC terminals of multiple IGBTs connected in parallel.

[0016] Optionally, in an embodiment of the present disclosure, the resistance value and quantity of the first resistors are determined by the driving protection requirement.

[0017] Optionally, in an embodiment of the present disclosure, the overvoltage hardware protection module includes a second resistor, a third resistor, a first capacitor, and a first diode; wherein,

[0018] The first end of the second resistor is connected to the first output end of the voltage analysis module, the second end of the second resistor is connected to the first end of the first capacitor, the connection point between the second end of the first capacitor, the positive electrode of the first diode and the first end of the third resistor is connected to the second output end of the voltage analysis module, and the connection point between the negative electrode of the first diode and the second end of the third resistor is connected to the IGBT drive circuit.

[0019] Optionally, in one embodiment of the present disclosure, the overvoltage hardware protection module further includes:

[0020] A plurality of overvoltage hardware protection units, wherein a first end of the overvoltage hardware protection unit is connected to a gate of the IGBT in a one-to-one correspondence, and a second end of the overvoltage hardware protection unit is connected to a second end of the first capacitor, an anode of the first diode, a first end of the third resistor, and a second output end of the voltage analysis module;

[0021] In a case where the second voltage signal meets the overvoltage forced protection requirement, the multiple IGBTs are controlled to be in an on state through the multiple overvoltage hardware protection units.

[0022] Optionally, in one embodiment of the present disclosure, the overvoltage hardware protection unit includes a second diode; wherein,

[0023] The anode of the second diode is respectively connected to the second end of the first capacitor, the anode of the first diode, the first end of the third resistor and the second output end of the voltage analysis module, and the cathode of the second diode is connected to the gate of the IGBT.

[0024] In summary, the multi-IGBT parallel overvoltage detection circuit provided by the embodiment of the present disclosure analyzes and calculates the first voltage signal based on the driving protection requirements through the voltage analysis module to obtain the second voltage signal after calculation and analysis. When the second voltage signal meets the overvoltage protection requirements, the overvoltage hardware protection module sends an overvoltage protection signal to the IGBT driving circuit, so that the IGBT driving circuit adjusts the on and off states of the multiple IGBTs according to the second voltage signal, thereby achieving the purpose of reducing the overvoltage, and realizing overvoltage suppression and feedback protection when driving multiple IGBTs connected in parallel.

[0025] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0027] Figure 1 A schematic diagram of a multi-IGBT parallel overvoltage detection circuit provided by an embodiment of the present disclosure;

[0028] Figure 2 A schematic structural diagram of a multi-IGBT parallel overvoltage detection circuit provided by another embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] Some embodiments of the present disclosure will be described in detail here, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. Various changes, modifications and equivalents of the structures described herein will become apparent after understanding the present disclosure. For example, the connection relationships of the structures described herein are merely examples and are not limited to those connection relationships set forth herein, but can be changed as becomes apparent after understanding the present disclosure, except for connections that must be made with specific connection relationships. In addition, for clarity and brevity, descriptions of features known in the art may be omitted.

[0030] The embodiments described in some embodiments of the present disclosure below do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of structures consistent with some aspects of the present disclosure as detailed in the appended claims.

[0031] It should be noted that IGBT power semiconductor devices are fully controlled devices with high voltage sensitivity, and are easily burned or exploded due to overvoltage. Considering the barrel effect of IGBT drive circuits and other issues, the industry usually increases the voltage resistance and current redundancy of IGBT devices, which results in poor economic efficiency after parallel connection. High-precision drive protection circuits, methods, and digital controllers are needed to solve the above problems.

[0032] The present disclosure is described in detail below with reference to specific embodiments.

[0033] Figure 1 This is a schematic diagram of a multi-IGBT parallel overvoltage detection circuit provided by an embodiment of the present disclosure. Figure 1 As shown, the multi-IGBT parallel overvoltage detection circuit includes: a voltage acquisition module, a voltage analysis module and an overvoltage hardware protection module; wherein,

[0034] A voltage acquisition module, used for acquiring a first voltage signal of a positive DC terminal of a plurality of IGBTs connected in parallel;

[0035] A voltage analysis module, used to analyze and calculate the first voltage signal based on the driving protection requirement to obtain a second voltage signal after calculation and analysis;

[0036] The overvoltage hardware protection module is used to send an overvoltage protection signal to the IGBT drive circuit when the second voltage signal meets the overvoltage protection requirements, so that the IGBT drive circuit adjusts the on-off state of multiple IGBTs according to the second voltage signal.

[0037] According to some embodiments, the drive protection requirement can be determined according to the actual application scenario. For example, the corresponding output voltage can be set according to different IGBT drive circuits and sampling voltage levels for IGBT drive control protection and status signal feedback.

[0038] In some embodiments, the overvoltage protection requirement can also be determined according to the actual application scenario. For example, the overvoltage protection requirement can be that the voltage value corresponding to the second voltage signal is greater than the first voltage threshold. The first voltage threshold does not specifically refer to a fixed threshold. The first voltage threshold can be determined, for example, according to the actual application scenario.

[0039] According to some embodiments, when the IGBT driving circuit adjusts the on / off states of multiple IGBTs according to the second voltage signal, the problem of overvoltage at the positive DC terminal of the IGBT can be suppressed, for example, by reducing the switching frequency of the output driving signal. The IGBT overvoltage can also be reduced by reducing the operating current to protect the device from damage. The specific method used can be determined according to the actual application scenario.

[0040] It should be noted that when the IGBT among the multiple IGBTs is an N-type IGBT, the positive DC terminal of the IGBT is the collector and the negative DC terminal is the emitter; when the IGBT among the multiple IGBTs is a P-type IGBT, the positive DC terminal of the IGBT is the emitter and the negative DC terminal is the collector.

[0041] It is easy to understand that the voltage analysis module analyzes and calculates the first voltage signal based on the driving protection requirements to obtain the second voltage signal after calculation and analysis. When the second voltage signal meets the overvoltage protection requirements, the overvoltage hardware protection module sends an overvoltage protection signal to the IGBT drive circuit, so that the IGBT drive circuit adjusts the on and off states of multiple IGBTs according to the second voltage signal, thereby achieving the purpose of reducing overvoltage and realizing overvoltage suppression and feedback protection when driving multiple IGBTs connected in parallel.

[0042] Optionally, in one embodiment of the present disclosure, Figure 2 This is a schematic diagram of a multi-IGBT parallel drive signal synchronization circuit provided by an embodiment of the present disclosure. Figure 2 As shown, the multi-IGBT parallel drive signal synchronization circuit includes M N-type IGBTs from IGBT1 to IGBTM, where M is a positive integer greater than 1. The collectors of the M N-type IGBTs are all connected to the positive DC power supply DC+, and the emitters of the M N-type IGBTs are all connected to the negative DC power supply DC-, thereby realizing parallel connection of the N IGBTs.

[0043] According to some embodiments, the gate of the IGBT is used to receive a drive signal input by the IGBT drive circuit. The drive signals received by different IGBTs may be the same or different, which may be determined according to the actual application scenario. The IGBT may be turned on and off according to the received drive signal.

[0044] In some embodiments, if the multiple IGBTs connected in parallel are P-type IGBTs, the emitters of the P-type IGBTs are all connected to the positive DC power supply DC+, and the collectors of the P-type IGBTs are all connected to the negative DC power supply DC-.

[0045] Optionally, in one embodiment of the present disclosure, the voltage analysis module includes a voltage acquisition unit, an intelligent control chip and a voltage logic output unit; wherein,

[0046] A voltage acquisition unit, used to convert the first voltage signal into a third voltage signal that meets the requirements of the intelligent control chip;

[0047] An intelligent control chip, used for analyzing and calculating the third voltage signal based on the driving protection requirement to obtain a fourth voltage signal after the calculation and analysis, wherein the fourth voltage signal is a digital signal;

[0048] The voltage logic output unit is used to convert the fourth voltage signal into an analog signal to obtain a second voltage signal.

[0049] According to some embodiments, the smart control chip requirement is used to indicate a voltage range that the smart control chip can accept.

[0050] In some embodiments, the intelligent control chip may be, for example, a high-speed intelligent control chip.

[0051] According to some embodiments, Figure 2 As shown, the voltage acquisition unit, the intelligent control chip and the voltage logic output unit are integrated in the intelligent voltage detection output logic control unit.

[0052] In some embodiments, the intelligent voltage detection output logic control unit may be a programmable voltage acquisition processing controller.

[0053] It is easy to understand that by designing a digital output high-speed voltage analysis module, the alarm value, first-level fault value and second-level fault value can be flexibly set according to different voltage levels, and the protection setting value can be flexibly adjusted, which can improve the flexibility and reliability of multi-IGBT parallel overvoltage detection.

[0054] Optionally, in one embodiment of the present disclosure, Figure 2 As shown, the voltage acquisition module includes N first resistors R1, where N is a positive integer; wherein,

[0055] The first end of the first first resistor R11 is grounded, the second end of the first first resistor R11 is connected to the first voltage input terminal Uin1 of the voltage analysis module and the first end of the second first resistor R12, the first end of the Nth first resistor R1N is connected to the second end of the N-1th first resistor R1N-1 and the N-1th voltage input terminal UinN-1 of the voltage analysis module, and the second end of the Nth first resistor R1N is connected to the Nth voltage input terminal UinN of the voltage analysis module and the positive DC terminals of multiple IGBTs connected in parallel.

[0056] According to some embodiments, the resistance value and number of the first resistors R1 are determined by the driving protection requirement.

[0057] In some embodiments, the first resistor R1 may be a precision sampling resistor with an accuracy level of ±1‰, thereby improving the accuracy of voltage sampling.

[0058] Taking a scenario as an example, a high-power wind power converter includes multiple stages of parallel-connected IGBT devices. The IGBT device is a power semiconductor device in the main circuit of the converter and is responsible for power conversion. Therefore, the drive protection requirement can be designed based on the main circuit voltage level of the high-power wind power converter and the protection voltage threshold required by the circuit, and then the resistance value and quantity of the first resistor R1 can be determined.

[0059] Optionally, in one embodiment of the present disclosure, Figure 2 As shown, the overvoltage hardware protection module includes a second resistor R2, a third resistor R3, a first capacitor C1, and a first diode D1; wherein,

[0060] The first end of the second resistor R2 is connected to the first output end of the voltage analysis module, the second end of the second resistor R2 is connected to the first end of the first capacitor C1, the connection point between the second end of the first capacitor C1, the positive electrode of the first diode D1 and the first end of the third resistor R3 is connected to the second output end of the voltage analysis module, and the connection point between the negative electrode of the first diode D1 and the second end of the third resistor R3 is connected to the IGBT drive circuit.

[0061] In some embodiments, the first end of the second resistor R2 is connected to the first output end Uout1 of the intelligent voltage detection output logic control unit, and the connection point between the second end of the first capacitor C1, the positive electrode of the first diode D1 and the first end of the third resistor R3 is connected to the second output end Uout2 of the intelligent voltage detection output logic control unit.

[0062] It should be noted that when the second voltage signal meets the overvoltage protection requirements, the second voltage signal can be fed back to the input end of the IGBT drive circuit through the second resistor R2, the third resistor R3, the first capacitor C1, and the first diode D1, and then the IGBT drive circuit controls the on and off of the IGBT to play a protective role.

[0063] Optionally, in one embodiment of the present disclosure, the overvoltage hardware protection module further includes:

[0064] Multiple overvoltage hardware protection units, the first end of the overvoltage hardware protection unit is connected to the gate of the IGBT in a one-to-one correspondence, and the second end of the overvoltage hardware protection unit is connected to the second end of the first capacitor C1, the anode of the first diode D1, the first end of the third resistor R3 and the second output end of the voltage analysis module.

[0065] In some embodiments, the second end of the overvoltage hardware protection unit is connected to the second end of the first capacitor C1, the anode of the first diode D1, the first end of the third resistor R3, and the second output end Uout2 of the intelligent voltage detection output logic control unit.

[0066] According to some embodiments, when the second voltage signal meets the overvoltage mandatory protection requirement, multiple IGBTs are controlled to be in an on state through multiple secondary overvoltage hardware protection circuits.

[0067] In some embodiments, the voltage mandatory protection requirement refers to the requirement adopted when the IGBT overvoltage cannot be reduced by adjusting the on-off state of multiple IGBTs according to the second voltage signal by the IGBT driving circuit alone, and mandatory measures are required. The overvoltage protection requirement can be, for example, that the voltage value corresponding to the second voltage signal is greater than the second voltage threshold. The second voltage threshold does not specifically refer to a fixed threshold. The second voltage threshold can be determined, for example, according to the actual application scenario.

[0068] According to some embodiments, Figure 2 As shown, the overvoltage hardware protection unit includes a second diode D2; wherein,

[0069] The anode of the second diode D2 is respectively connected to the second end of the first capacitor C1, the anode of the first diode D1, the first end of the third resistor R3 and the second output end of the voltage analysis module, and the cathode of the second diode D2 is connected to the gate of the IGBT.

[0070] In some embodiments, the second diode in the first overvoltage hardware protection unit in the multi-IGBT parallel overvoltage detection circuit is D21; the second diode in the Nth overvoltage hardware protection unit is D2N. Figure 2As shown, the positive electrode of D21 is connected to the second end of the first capacitor C1, the positive electrode of the first diode D1, the first end of the third resistor R3 and the second output end Uout2 of the intelligent voltage detection output logic control unit, and the negative electrode of D21 is connected to the gate of IGBT1; the positive electrode of D2N is connected to the second end of the first capacitor C1, the positive electrode of the first diode D1, the first end of the third resistor R3 and the second output end Uout2 of the intelligent voltage detection output logic control unit, and the negative electrode of D2N is connected to the gate of IGBTN.

[0071] It should be noted that after the overvoltage detection circuit detects that the voltage corresponding to the positive DC terminal is greater than the first voltage threshold and controls the on and off states of multiple IGBTs through the IGBT drive circuit, if the voltage corresponding to the positive DC terminal is still rising and rises to be greater than the second voltage threshold, multiple overvoltage hardware protection units can be set up to interlock with the IGBT drive circuit, drive the IGBT drive circuit to forcibly block the IGBT drive pulse, directly apply the trigger point to the control gate of the IGBT, and then turn on the IGBT, thereby reducing the overvoltage, thereby ensuring equipment safety and improving the reliability of the multi-IGBT parallel overvoltage detection circuit.

[0072] Optionally, in one embodiment of the present disclosure, the components involved in the multi-IGBT parallel overvoltage detection circuit, including but not limited to the first resistor R1, the second resistor R2, the third resistor R3, the first capacitor C1, the first diode D1, the second diode D2, etc., can all adopt high-precision devices, thereby further improving the accuracy of multi-IGBT parallel overvoltage detection.

[0073] In addition, the word "exemplary" is used herein to indicate serving as an example, instance, or diagram. Any aspect or design described as "exemplary" in this article is not necessarily understood to be advantageous compared to other aspects or designs. On the contrary, the use of the word exemplary is intended to present concepts in a specific way. As used herein, the term "or" is intended to represent an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X applies A or B" is intended to represent any one of the natural inclusive arrangements. That is, if X applies A; X applies B; or X applies both A and B, "X applies A or B" is satisfied under any of the aforementioned examples. In addition, unless otherwise specified or clearly pointed to a singular form from the context, the articles "one" and "an" as used in this application and the appended claims are generally understood to mean "one or more".

[0074] Likewise, although the present disclosure has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art after reading and understanding the specification and drawings. The present disclosure includes all such modifications and variations and is limited only by the scope of the claims. In particular, with respect to the various functions performed by the components (e.g., elements, resources, etc.) described above, unless otherwise noted, the terms used to describe such components are intended to correspond to any component (functionally equivalent) that performs the specific functions of the described components, even if the structure is not equivalent to the disclosed structure. In addition, although the specific features of the present disclosure may have been disclosed with respect to only one of several implementations, such features may be combined with one or more other features of other implementations as may be desired and conducive to any given or specific application. In addition, with respect to "including", "having", "having", "having", or variations thereof used in the specific embodiments or claims, such terms are intended to be inclusive in a manner similar to the term "comprising".

[0075] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0076] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A multi-IGBT parallel overvoltage detection circuit, characterized in that: include: Voltage acquisition module, voltage analysis module and overvoltage hardware protection module; among them, The voltage acquisition module is used to acquire a first voltage signal of a positive DC terminal of a plurality of IGBTs connected in parallel; The voltage analysis module is used to analyze and calculate the first voltage signal based on the driving protection requirement to obtain a second voltage signal after calculation and analysis; The overvoltage hardware protection module is used to send an overvoltage protection signal to the IGBT drive circuit when the second voltage signal meets the overvoltage protection requirements, so that the IGBT drive circuit adjusts the on and off states of the multiple IGBTs according to the second voltage signal.

2. The multi-IGBT parallel overvoltage detection circuit according to claim 1, characterized in that: The voltage analysis module includes a voltage acquisition unit, an intelligent control chip and a voltage logic output unit; wherein, The voltage acquisition unit is used to convert the first voltage signal into a third voltage signal that meets the requirements of the intelligent control chip; The intelligent control chip is used to analyze and calculate the third voltage signal based on the driving protection requirement to obtain a fourth voltage signal after calculation and analysis, wherein the fourth voltage signal is a digital signal; The voltage logic output unit is used to convert the fourth voltage signal into an analog signal to obtain the second voltage signal.

3. The multi-IGBT parallel overvoltage detection circuit according to claim 2, characterized in that: The voltage acquisition unit, the intelligent control chip and the voltage logic output unit are integrated in an intelligent voltage detection output logic control unit.

4. The multi-IGBT parallel overvoltage detection circuit according to claim 3, characterized in that: The intelligent voltage detection output logic control unit is a programmable voltage acquisition processing controller.

5. The multi-IGBT parallel overvoltage detection circuit according to claim 1, characterized in that: The voltage acquisition module includes N first resistors, where N is a positive integer; wherein, The first end of the first first resistor is grounded, the second end of the first first resistor is connected to the first voltage input terminal of the voltage analysis module and the first end of the second first resistor, the first end of the Nth first resistor is connected to the second end of the N-1th first resistor and the N-1th voltage input terminal of the voltage analysis module, and the second end of the Nth first resistor is connected to the Nth voltage input terminal of the voltage analysis module and the positive DC terminals of multiple IGBTs connected in parallel.

6. The multi-IGBT parallel overvoltage detection circuit according to claim 5, characterized in that: The resistance value and quantity of the first resistors are determined by the driving protection requirement.

7. The multi-IGBT parallel overvoltage detection circuit according to claim 1, characterized in that: The overvoltage hardware protection module includes a second resistor, a third resistor, a first capacitor, and a first diode; wherein, The first end of the second resistor is connected to the first output end of the voltage analysis module, the second end of the second resistor is connected to the first end of the first capacitor, the connection point between the second end of the first capacitor, the positive electrode of the first diode and the first end of the third resistor is connected to the second output end of the voltage analysis module, and the connection point between the negative electrode of the first diode and the second end of the third resistor is connected to the IGBT drive circuit.

8. The multi-IGBT parallel overvoltage detection circuit according to claim 7, characterized in that: The overvoltage hardware protection module also includes: A plurality of overvoltage hardware protection units, wherein a first end of the overvoltage hardware protection unit is connected to a gate of the IGBT in a one-to-one correspondence, and a second end of the overvoltage hardware protection unit is connected to a second end of the first capacitor, an anode of the first diode, a first end of the third resistor, and a second output end of the voltage analysis module; In a case where the second voltage signal meets the overvoltage forced protection requirement, the multiple IGBTs are controlled to be in an on state through the multiple overvoltage hardware protection units.

9. The multi-IGBT parallel overvoltage detection circuit according to claim 8, characterized in that: The overvoltage hardware protection unit includes a second diode; wherein, The anode of the second diode is respectively connected to the second end of the first capacitor, the anode of the first diode, the first end of the third resistor and the second output end of the voltage analysis module, and the cathode of the second diode is connected to the gate of the IGBT.

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