Converter valve sub-module IGBT switching frequency over-limit fault protection method and converter valve sub-module IGBT switching frequency over-limit fault protection device

Abstract

The invention relates to the technical field of flexible direct-current power transmission, and particularly provides a converter valve submodule IGBT switching frequency over-limit fault protection method and device, and the method comprises the steps: carrying out the switching frequency over-limit fault diagnosis of an IGBT based on a converter valve bridge arm current effective value and the switching frequency of the IGBT in a submodule on a converter valve bridge arm; and performing switching frequency over-limit fault protection on the converter valve based on the number of the sub-modules with the switching frequency over-limit fault in the converter valve. According to the technical scheme provided by the invention, on the basis of realizing rapid judgment of a switching frequency over-limit fault, the IGBT detection completeness is improved, the valve control pressure is reasonably reduced by division of labor, and meanwhile, a protection strategy is designed to improve the availability rate of the converter valve sub-module as much as possible.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible direct current transmission, and in particular to a method and device for protecting a converter valve submodule from an IGBT switching frequency over-limit fault. Background Art

[0002] Flexible direct current (HVDC) transmission technology, utilizing a modular multilevel converter topology, is a new transmission technology enabling large-scale external transmission from the Shagohuang wind and solar power base, flexible grid interconnection, and offshore wind power grid integration. It is a strategically important technology for building a new power system and achieving a low-carbon energy transition. The converter valve submodule, the "heart" of flexible HVDC transmission, converts electrical energy through the on / off operation of IGBT devices. If the IGBT is turned on and off frequently, the resulting switching damage can cause the junction temperature of the IGBT device to rise. In severe cases, exceeding the junction temperature limit can cause overheating and damage to the IGBT device, leading to submodule failure, loss of redundancy, and even system shutdown. Therefore, designing a fast and comprehensive method for diagnosing excessive IGBT switching frequency faults in flexible HVDC submodules, as well as efficient protection methods, is crucial to the operation of flexible HVDC projects.

[0003] Patent CN 202210708501.X proposes a high-frequency protection method for flexible direct current submodules. However, its switching frequency overclocking fault judgment design is in the valve control system. As the number of submodules increases, the resource demand of the valve control system increases greatly. Moreover, in this invention patent, a bypass operation needs to be performed if the high-frequency action of the submodule occurs at most twice in a row, which greatly reduces the availability of the submodule. A temporary locking operation is performed after the first fault occurs, which can easily trigger the capacitor voltage overvoltage bypass. Summary of the Invention

[0004] In order to overcome the above-mentioned defects, the present invention proposes a method and device for protecting a converter valve submodule from an IGBT switching frequency over-limit fault.

[0005] In a first aspect, a method for protecting a converter valve submodule from an IGBT switching frequency over-limit fault is provided. The method for protecting a converter valve submodule from an IGBT switching frequency over-limit fault comprises:

[0006] Performing switching frequency over-limit fault diagnosis on the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm;

[0007] The converter valve is protected against switching frequency over-limit faults based on the number of submodules in the converter valve that have switching frequency over-limit faults.

[0008] Preferably, the converter valve adopts a half-bridge topology structure.

[0009] Furthermore, the switching frequency exceeding limit fault diagnosis of the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm includes:

[0010] When the effective value of the current of the converter valve bridge arm does not exceed the current threshold, it is determined whether the switching frequency of the IGBT in the upper sub-module of the converter valve bridge arm exceeds the first switching frequency threshold within the first preset time period. If so, the IGBT in the upper sub-module of the converter valve bridge arm has a switching frequency exceeding limit fault in the low current mode. Otherwise, the IGBT in the upper sub-module of the converter valve bridge arm has not a switching frequency exceeding limit fault in the low current mode.

[0011] Furthermore, the switching frequency exceeding limit fault diagnosis of the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm includes:

[0012] When the effective value of the current of the converter valve bridge arm exceeds the current threshold, it is determined whether the switching frequency of the IGBT in the upper sub-module of the converter valve bridge arm exceeds the second switching frequency threshold within the second preset time period. If so, the IGBT in the upper sub-module of the converter valve bridge arm has a switching frequency exceeding limit fault in the high current mode. Otherwise, the IGBT in the upper sub-module of the converter valve bridge arm has not a switching frequency exceeding limit fault in the high current mode.

[0013] Furthermore, the switching frequency over-limit fault protection of the converter valve based on the number of submodules in the converter valve that have a switching frequency over-limit fault includes:

[0014] When the number of submodules in the converter valve having a switching frequency over-limit fault does not exceed a quantity threshold, a trigger instruction is issued to the lower IGBT of the submodule in the converter valve having a switching frequency over-limit fault, and normal switching of the lower IGBT is restored after a third preset period of time;

[0015] When the number of submodules in the converter valve that have switching frequency over-limit faults exceeds a quantity threshold, the converter valve is controlled to perform a system switching operation.

[0016] Furthermore, the quantity threshold is half of the total number of submodules in the converter valve.

[0017] Furthermore, the third preset time period is 100ms.

[0018] In a second aspect, a converter valve submodule IGBT switching frequency over-limit fault protection device is provided, wherein the converter valve submodule IGBT switching frequency over-limit fault protection device comprises:

[0019] A fault diagnosis module is used to diagnose an IGBT switching frequency over-limit fault based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the sub-module on the converter valve bridge arm;

[0020] The protection module is used to protect the converter valve from switching frequency over-limit faults based on the number of submodules in the converter valve that have switching frequency over-limit faults.

[0021] In a third aspect, a computer device is provided, comprising: one or more processors;

[0022] The processor is configured to execute one or more programs;

[0023] When the one or more programs are executed by the one or more processors, the converter valve submodule IGBT switching frequency over-limit fault protection method is implemented.

[0024] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed, the converter valve submodule IGBT switching frequency over-limit fault protection method is implemented.

[0025] The above one or more technical solutions of the present invention have at least one or more of the following beneficial effects:

[0026] The present invention provides a method and device for protecting a converter valve submodule from an IGBT switching frequency over-limit fault. The method comprises: diagnosing an IGBT switching frequency over-limit fault based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBTs in the submodules in that bridge arm; and protecting the converter valve from this switching frequency over-limit fault based on the number of submodules in the converter valve experiencing the switching frequency over-limit fault. The technical solution provided by the present invention not only enables rapid diagnosis of switching frequency over-limit faults, but also improves the comprehensiveness of IGBT detection, reduces valve control pressure through rational division of labor, and designs a protection strategy to maximize the availability of the converter valve submodules. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 1 is a flow chart of the main steps of a method for protecting a converter valve submodule from an IGBT switching frequency over-limit fault according to an embodiment of the present invention;

[0028] Figure 2 This is a functional block diagram of an IGBT switching frequency over-limit protection according to an embodiment of the present invention;

[0029] Figure 3 Schematic diagram of the division of IGBT switching frequency over-limit protection functions according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0032] Example 1

[0033] See attached Figure 1 , Figure 1 This is a flow chart of the main steps of a method for protecting the IGBT switching frequency over-limit fault of a converter valve submodule according to an embodiment of the present invention. Figure 1 As shown, the converter valve submodule IGBT switching frequency over-limit fault protection method in the embodiment of the present invention mainly includes the following steps:

[0034] Step S101: performing switching frequency over-limit fault diagnosis on the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm;

[0035] Step S102: performing switching frequency over-limit fault protection on the converter valve based on the number of submodules in the converter valve that have switching frequency over-limit faults.

[0036] Wherein, the converter valve adopts a half-bridge topology structure.

[0037] In one embodiment, the step of performing a switching frequency over-limit fault diagnosis on the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm includes:

[0038] When the effective value of the current of the converter valve bridge arm does not exceed the current threshold, it is determined whether the switching frequency of the IGBT in the upper sub-module of the converter valve bridge arm exceeds the first switching frequency threshold within the first preset time period. If so, the IGBT in the upper sub-module of the converter valve bridge arm has a switching frequency exceeding limit fault in the low current mode. Otherwise, the IGBT in the upper sub-module of the converter valve bridge arm has not a switching frequency exceeding limit fault in the low current mode.

[0039] In one embodiment, the step of performing a switching frequency over-limit fault diagnosis on the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm includes:

[0040] When the effective value of the current of the converter valve bridge arm exceeds the current threshold, it is determined whether the switching frequency of the IGBT in the upper sub-module of the converter valve bridge arm exceeds the second switching frequency threshold within the second preset time period. If so, the IGBT in the upper sub-module of the converter valve bridge arm has a switching frequency exceeding limit fault in the high current mode. Otherwise, the IGBT in the upper sub-module of the converter valve bridge arm has not a switching frequency exceeding limit fault in the high current mode.

[0041] In one embodiment, the step of protecting the converter valve from a switching frequency over-limit fault based on the number of submodules in the converter valve that have a switching frequency over-limit fault includes:

[0042] When the number of submodules in the converter valve having a switching frequency over-limit fault does not exceed a quantity threshold, a trigger instruction is issued to the lower IGBT of the submodule in the converter valve having a switching frequency over-limit fault, and normal switching of the lower IGBT is restored after a third preset period of time;

[0043] When the number of submodules in the converter valve that have switching frequency over-limit faults exceeds a quantity threshold, the converter valve is controlled to perform a system switching operation.

[0044] In one embodiment, the quantity threshold is half of the total number of submodules in the converter valve.

[0045] In one embodiment, the third preset time period is 100 ms.

[0046] In a specific embodiment, Figure 2 As shown, the diagnostic process of the converter valve submodule IGBT switching frequency over-limit fault protection method includes:

[0047] (1) Currently, most of the flexible DC converter valve submodules in operation adopt half-bridge topology, such as Figure 3 As shown, each submodule contains two IGBTs, an upper IGBT (marked as D1) and a lower IGBT (marked as D2). The IGBT switching frequency over-limit fault judgment proposed in this patent is to judge both D1 and D2 at the same time.

[0048] (2) Calculate the switching frequencies f11 and f12 of the upper and lower IGBTs during time T1, compare them with the first switching frequency threshold F1, and perform a logical “OR” operation on the judgment results to obtain the IGBT switching frequency over-limit fault in the low current mode;

[0049] (3) Calculate the switching frequencies f21 and f22 of the upper and lower IGBTs during time T2, compare them with the second switching frequency threshold F2, and perform a logical “OR” operation on the judgment results to obtain an IGBT switching frequency over-limit fault in the high current mode;

[0050] (4) The valve control calculates the effective value of the bridge arm current iarm in real time and compares it with the current threshold I: if iarm < I, a low current mode is generated; otherwise, a high current mode is generated;

[0051] (5) According to the large / small current mode, the IGBT overfrequency fault in the large / small current mode determined in (2) and (3) above is selected as the sub-module IGBT overfrequency fault of the final exit;

[0052] (6) When calculating the IGBT switching frequency in (2) and (3) above, a sliding window statistical method is used to improve the detection accuracy and fast response speed. There are two typical designs: one is to follow the IGBT trigger instruction timing issued by the valve control system; the other is to implement double frequency sampling based on the sampling theorem (for example, if the valve control cycle is 50μs, then the IGBT is sampled every 25μs to determine whether it is performing an on / off operation).

[0053] The protection process of the converter valve submodule IGBT switching frequency over-limit fault protection method includes:

[0054] (1) The calculation of the effective value of the bridge arm current and the generation of the large / small current mode are configured in the valve control system, and the large / small current mode is sent to the sub-module central control board;

[0055] (2) The submodule central control board calculates the IGBT switching frequency, determines whether the switching frequency exceeds the limit in the large / small current mode, and outputs the final submodule IGBT switching frequency exceeding the limit fault according to the large / small current mode, and sends the fault to the valve control system;

[0056] (3) If the valve control system detects that only a few submodules have IGBT switching frequency exceeding the limit, it will temporarily send a triggering instruction to the lower IGBT (i.e., D2) to the submodule. The submodule will not participate in supporting the DC voltage, and the capacitor voltage will slowly discharge through the voltage-sharing resistor. After a period of time (e.g., 100ms) after temporarily sending the triggering instruction to the lower IGBT, the valve control will resume normal switching of the submodule. The submodule central control board will also start the IGBT switching frequency exceeding limit fault judgment logic. If the IGBT switching frequency exceeding limit fault occurs again, the above operation will continue to be executed.

[0057] (4) If the valve control system detects that most submodules (such as half of the redundant submodules) have IGBT overfrequency failures at the same time, the valve control system will apply for system switching operation to avoid the IGBT submodule switching frequency exceeding the limit caused by the valve control system failure, thereby improving the availability of the flexible direct current system;

[0058] (5) The parameter setting mode of the valve control system can be used to easily modify the judgment threshold of the large / small current mode, the time and threshold of the IGBT switching frequency judgment, and the time and threshold of the IGBT switching frequency judgment are then sent to the central control board for execution through the downlink communication optical fiber between the valve control system and the sub-module central control board;

[0059] (6) The above protection logic is completed by the valve control system and the sub-module central control board through division of labor and cooperation, which has little impact on the resource utilization rate of the valve control system. Even if the number of sub-modules increases, the impact on the valve control system is also small.

[0060] The above statement is for the half-bridge sub-module. If the flexible DC converter valve sub-module adopts a full-bridge sub-module (each sub-module contains 4 IGBTs) or an MMC topology with distributed energy-dissipating resistors (each sub-module contains 3 IGBTs or 5 IGBTs), the central control board needs to calculate the switching frequency of all IGBTs inside the sub-module and determine whether a frequency over-limit fault occurs.

[0061] Figure 2 In1 and In 2 represent two input ports, Se1 represents the setting port, and Out represents the output port. Figure 3 In , SM represents submodule.

[0062] Example 2

[0063] Based on the same inventive concept, the present invention further provides a converter valve submodule IGBT switching frequency over-limit fault protection device, the converter valve submodule IGBT switching frequency over-limit fault protection device comprising:

[0064] A fault diagnosis module is used to diagnose an IGBT switching frequency over-limit fault based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the sub-module on the converter valve bridge arm;

[0065] The protection module is used to protect the converter valve from switching frequency over-limit faults based on the number of submodules in the converter valve that have switching frequency over-limit faults.

[0066] Preferably, the converter valve adopts a half-bridge topology structure.

[0067] Furthermore, the switching frequency exceeding limit fault diagnosis of the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm includes:

[0068] When the effective value of the current of the converter valve bridge arm does not exceed the current threshold, it is determined whether the switching frequency of the IGBT in the upper sub-module of the converter valve bridge arm exceeds the first switching frequency threshold within the first preset time period. If so, the IGBT in the upper sub-module of the converter valve bridge arm has a switching frequency exceeding limit fault in the low current mode. Otherwise, the IGBT in the upper sub-module of the converter valve bridge arm has not a switching frequency exceeding limit fault in the low current mode.

[0069] Furthermore, the switching frequency exceeding limit fault diagnosis of the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm includes:

[0070] When the effective value of the current of the converter valve bridge arm exceeds the current threshold, it is determined whether the switching frequency of the IGBT in the upper sub-module of the converter valve bridge arm exceeds the second switching frequency threshold within the second preset time period. If so, the IGBT in the upper sub-module of the converter valve bridge arm has a switching frequency exceeding limit fault in the high current mode. Otherwise, the IGBT in the upper sub-module of the converter valve bridge arm has not a switching frequency exceeding limit fault in the high current mode.

[0071] Furthermore, the switching frequency over-limit fault protection of the converter valve based on the number of submodules in the converter valve that have a switching frequency over-limit fault includes:

[0072] When the number of submodules in the converter valve having a switching frequency over-limit fault does not exceed a quantity threshold, a trigger instruction is issued to the lower IGBT of the submodule in the converter valve having a switching frequency over-limit fault, and normal switching of the lower IGBT is restored after a third preset period of time;

[0073] When the number of submodules in the converter valve that have switching frequency over-limit faults exceeds a quantity threshold, the converter valve is controlled to perform a system switching operation.

[0074] Furthermore, the quantity threshold is half of the total number of submodules in the converter valve.

[0075] Furthermore, the third preset time period is 100ms.

[0076] Example 3

[0077] Based on the same inventive concept, the present invention also provides a computer device, comprising a processor and a memory, wherein the memory is configured to store a computer program, wherein the computer program includes program instructions, and the processor is configured to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., and is the computing core and control core of the terminal, and is adapted to implement one or more instructions, specifically, to load and execute one or more instructions in the computer storage medium to implement a corresponding method flow or corresponding function, so as to implement the steps of a method for protecting the IGBT switching frequency over-limit fault of a converter valve submodule in the above-mentioned embodiment.

[0078] Example 4

[0079] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space that stores the terminal's operating system. In addition, the storage space also stores one or more instructions suitable for being loaded and executed by the processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the converter valve submodule IGBT switching frequency over-limit fault protection method in the above embodiment.

[0080] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0081] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0082] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0083] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for protecting a converter valve submodule from an IGBT switching frequency over-limit fault, characterized in that: The method comprises: Performing switching frequency over-limit fault diagnosis on the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm; The converter valve is protected against switching frequency over-limit faults based on the number of submodules in the converter valve that have switching frequency over-limit faults.

2. The method according to claim 1, wherein The converter valve adopts a half-bridge topology structure.

3. The method according to claim 2, wherein The method of performing switching frequency over-limit fault diagnosis on the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm includes: When the effective value of the current of the converter valve bridge arm does not exceed the current threshold, it is determined whether the switching frequency of the IGBT in the upper sub-module of the converter valve bridge arm exceeds the first switching frequency threshold within the first preset time period. If so, the IGBT in the upper sub-module of the converter valve bridge arm has a switching frequency exceeding limit fault in the low current mode. Otherwise, the IGBT in the upper sub-module of the converter valve bridge arm has not a switching frequency exceeding limit fault in the low current mode.

4. The method according to claim 2, wherein The method of performing switching frequency over-limit fault diagnosis on the IGBT based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the submodule on the converter valve bridge arm includes: When the effective value of the current of the converter valve bridge arm exceeds the current threshold, it is determined whether the switching frequency of the IGBT in the upper sub-module of the converter valve bridge arm exceeds the second switching frequency threshold within the second preset time period. If so, the IGBT in the upper sub-module of the converter valve bridge arm has a switching frequency exceeding limit fault in the high current mode. Otherwise, the IGBT in the upper sub-module of the converter valve bridge arm has not a switching frequency exceeding limit fault in the high current mode.

5. The method according to claim 2, wherein The method of performing switching frequency over-limit fault protection on the converter valve based on the number of submodules in the converter valve that have switching frequency over-limit faults includes: When the number of submodules in the converter valve having a switching frequency over-limit fault does not exceed a quantity threshold, a trigger instruction is issued to the lower IGBT of the submodule in the converter valve having a switching frequency over-limit fault, and normal switching of the lower IGBT is restored after a third preset period of time; When the number of submodules in the converter valve that have switching frequency over-limit faults exceeds a quantity threshold, the converter valve is controlled to perform a system switching operation.

6. The method according to claim 5, wherein The quantity threshold is half of the total number of submodules in the converter valve.

7. The method according to claim 5, wherein The third preset time period is 100ms.

8. A device based on the converter valve submodule IGBT switching frequency over-limit fault protection method according to any one of claims 1 to 7, characterized in that: The device comprises: A fault diagnosis module is used to diagnose an IGBT switching frequency over-limit fault based on the effective value of the converter valve bridge arm current and the switching frequency of the IGBT in the sub-module on the converter valve bridge arm; The protection module is used to protect the converter valve from switching frequency over-limit faults based on the number of submodules in the converter valve that have switching frequency over-limit faults.

9. A computer device, characterized in that: include: one or more processors; The processor is configured to execute one or more programs; When the one or more programs are executed by the one or more processors, the converter valve submodule IGBT switching frequency over-limit fault protection method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that A computer program is stored thereon, and when the computer program is executed, the method for protecting the converter valve submodule IGBT switching frequency over-limit fault according to any one of claims 1 to 7 is implemented.

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