Control method of FRD device

Abstract

The invention provides a control method of an FRD device. According to the method, voltage signals at the two ends of an FRD device in a circuit are obtained, if it is determined that a transient pulse signal exists in the current time period according to the voltage signals and the maximum voltage value exceeds a preset voltage threshold value, energy integration in the current time period is determined, and if the energy integration is larger than a preset energy integration threshold value, energy integration is determined. If yes, a control chip in the control circuit closes a switching tube of a branch circuit where the FRD device is located in the next time period, so that the problem of overvoltage failure of the FRD device and related circuits caused by non-periodic transient pulses is effectively avoided, and overvoltage protection of the circuit provided with the FRD device is achieved.

Description

Technical Field

[0001] This application relates to data processing technology, and more particularly to a control method for an FRD device. Background Technology

[0002] In the field of power electronics technology, the three-phase inverter bridge arm circuit is a very common and critical circuit structure, widely used in many applications such as motor drive, uninterruptible power supply, and new energy power generation (such as solar inverters and wind power converters).

[0003] The core function of this circuit is to convert direct current (DC) to alternating current (AC) to meet the energy requirements of different loads. In the three-phase inverter bridge arm circuit, the fast recovery diode (FRD) is a crucial power device. The FRD is typically used in conjunction with a switching transistor, and its main function is to provide a freewheeling path for inductive loads (such as motors). When the switching transistor is turned off, the inductive load generates a back electromotive force (EMF). Without the freewheeling path provided by the FRD, the energy in the load cannot be released, resulting in extremely high voltage spikes across the switching transistor, potentially damaging it. Therefore, the performance and reliability of the FRD directly affect the normal operation of the entire three-phase inverter bridge arm circuit.

[0004] However, in practical applications, three-phase inverter bridge arm circuits face the problem of overvoltage failure. The back electromotive force generated by inductive loads (such as motors) during operation, and the voltage spikes caused by parasitic inductances in the circuit (such as line inductance, transformer leakage inductance, etc.) when the switching transistors are turned off, may exceed the reverse withstand voltage of the FRD. Once the voltage exceeds the reverse withstand voltage of the FRD, reverse breakdown will occur. At this time, the reverse leakage current of the FRD will suddenly increase; excessive current will damage the insulation layer, eventually forming a permanent short circuit, causing the entire circuit to malfunction and severely affecting the stability and reliability of the system. Summary of the Invention

[0005] This application provides a control method for an FRD device to solve the technical problem of overvoltage failure of the FRD device and related circuits caused by non-periodic transient pulses.

[0006] Firstly, this application provides a control method for an FRD device, comprising: Obtain the voltage signal across the FRD device in the circuit; If, based on the voltage signal, it is determined that a transient pulse signal exists within the current time period and the maximum voltage value exceeds a preset voltage threshold, then the energy integral within the current time period is determined. If the energy integral is greater than the preset energy integral threshold, the control chip in the circuit will turn off the switching transistor of the branch where the FRD device is located in the next time period.

[0007] Optionally, determining the presence of a transient pulse signal within the current time period based on the voltage signal includes: If the ratio of the duration of the voltage signal greater than a preset pulse voltage threshold to the duration of the current time period is greater than a preset ratio threshold, then it is determined that there is a transient pulse signal in the current time period, wherein the duration is a continuous and uninterrupted duration.

[0008] Optionally, determining the presence of a transient pulse signal within the current time period based on the voltage signal includes: If the voltage change rate of the voltage signal during the current time period is greater than a preset change rate threshold, then it is determined that there is a transient pulse signal during the current time period.

[0009] Optionally, determining the presence of a transient pulse signal within the current time period based on the voltage signal includes: If there is a local waveform in the voltage signal whose matching degree with the preset transient pulse waveform exceeds the preset matching degree, then it is determined that the transient pulse signal exists in the current time period.

[0010] Optionally, the transient pulse signal is a non-periodic transient pulse signal, wherein the non-periodicity is used to characterize that the transient pulse signal does not have a fixed period within the current time period.

[0011] Optionally, determining the energy integral within the current time period includes: The ratio between the square of the voltage signal and the load impedance of the circuit is integrated during the current time period to determine the energy integral.

[0012] Optionally, a TVS diode is connected in parallel across the two ends of the FRD device, wherein the clamping voltage of the TVS diode is less than the reverse withstand voltage threshold of the FRD device.

[0013] Secondly, this application provides a three-phase inverter bridge arm circuit, including: FRD devices disposed on each bridge arm; The FRD device is overvoltage protected by the control method of the FRD device as described in any one of the first aspects.

[0014] Thirdly, this application provides an electronic device, comprising: Processor; and, Memory for storing the executable instructions of the processor; The processor is configured to perform any of the possible methods described in the first aspect by executing the executable instructions.

[0015] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement any of the possible methods described in the first aspect.

[0016] The control method for the FRD device provided in this application obtains the voltage signal across the FRD device in the circuit. If it is determined from the voltage signal that a transient pulse signal exists in the current time period and the maximum voltage value exceeds a preset voltage threshold, the energy integral in the current time period is determined. If the energy integral is greater than the preset energy integral threshold, the control chip in the control circuit turns off the switching transistor of the branch where the FRD device is located in the next time period. This effectively avoids the problem of overvoltage failure of the FRD device and related circuits caused by non-periodic transient pulses, thereby achieving overvoltage protection for the circuit in which the FRD device is set. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] Figure 1 This is a schematic flowchart illustrating a control method for an FRD device according to an example embodiment of this application; Figure 2 This is a voltage signal waveform diagram illustrated in an example embodiment of this application; Figure 3 This is a waveform diagram of a preset transient pulse waveform shown in an example embodiment of this application; Figure 4 This is a schematic diagram of the structure of an electronic device according to an example embodiment of this application.

[0019] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0020] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0021] To provide overvoltage protection for FRDs, a common approach is to connect a TVS (Transient Voltage Suppressor) diode in parallel across the FRD. The TVS diode operates by utilizing its clamping characteristic, setting its clamping voltage (Vc) below the FRD's VRRM. When a voltage spike occurs in the circuit and exceeds the TVS diode's clamping voltage, the TVS diode quickly conducts, dissipating the overvoltage energy to ground, thus protecting the FRD from overvoltage damage.

[0022] However, existing TVS diode clamping protection schemes are mainly suitable for protecting against periodic switching noise and are insufficient for handling non-periodic transient energy. In actual operation, the three-phase inverter bridge arm circuit may encounter various non-periodic high-energy pulse situations. For example, a bridge arm short-circuit fault or abnormal motor back EMF may generate non-periodic high-energy pulses, which may release a large amount of energy (e.g., 10mJ) in a very short time (e.g., within 100μs).

[0023] Existing TVS diodes are designed with energy handling capacity in mind under periodic operating conditions. When faced with non-periodic high-energy pulses, TVS diodes are easily burned out due to energy overload, thus losing their overvoltage protection function and failing to effectively ensure the safe operation of the FRD and the entire three-phase inverter bridge arm circuit.

[0024] The embodiments of this application aim to obtain the voltage signal across the FRD device in the three-phase inverter bridge arm circuit and determine whether there is a transient pulse signal in the current time period based on the set conditions.

[0025] The judgment conditions include: the ratio of the duration of the voltage signal exceeding a preset pulse voltage threshold to the duration of the current time period being greater than a preset ratio threshold; the rate of change of the voltage signal within the current time period being greater than a preset rate of change threshold; and the presence of local waveforms in the voltage signal whose matching degree with a preset transient pulse waveform exceeds a preset matching degree. The above-mentioned judgment method can accurately identify non-periodic transient pulse signals, such as pulses generated by bridge arm short circuits or motor back electromotive force. Existing TVS diode clamping protection schemes mainly target periodic switching noise and are insufficient in handling non-periodic transient energy. The solution in this application aims to provide corresponding overvoltage protection by identifying non-periodic transient pulses, based on the TVS diode clamping protection scheme.

[0026] After confirming the presence of a transient pulse signal, the system further determines whether the maximum voltage value in the voltage signal exceeds a preset voltage threshold. If it does, the energy integral for the current time period is determined. The energy integral is obtained by integrating the ratio of the square of the voltage signal to the load impedance of the three-phase inverter bridge arm circuit over the current time period. This method, which considers both voltage amplitude and energy magnitude, is more reliable than relying solely on voltage amplitude for protection. Even if the voltage amplitude exceeds the preset voltage threshold, a small energy integral may not cause substantial damage to the FRD device or TVS diode. However, when the energy integral exceeds the preset energy integral threshold, it indicates that the transient pulse carries sufficient energy to seriously threaten the FRD device and TVS diode, triggering the protection action only at this point. This avoids frequent switching shutdowns due to misjudgment, improving the stability and reliability of the circuit.

[0027] When the energy integral exceeds a preset energy integral threshold, in the embodiments of this application, the control chip in the three-phase inverter bridge arm circuit can be controlled to turn off the switching transistor of the bridge arm where the FRD device is located in the next time period. This timely control measure can quickly cut off the current path of the bridge arm where the FRD device is located, preventing overvoltage energy from continuing to damage the FRD device. In the three-phase inverter bridge arm circuit, the reverse withstand voltage of the FRD device is limited. When encountering a high-energy transient pulse, if protective measures are not taken in time, the FRD device is prone to reverse breakdown, resulting in a sudden increase in reverse leakage current, damage to the insulation layer, and the formation of a permanent short circuit. This method, by turning off the switching transistor in time, can effectively avoid this situation, extend the service life of the FRD device, and ensure the normal operation of the entire three-phase inverter bridge arm circuit.

[0028] Existing TVS diode clamping protection schemes are prone to damage when encountering non-periodic high-energy pulses due to their limited energy handling capacity, requiring frequent TVS diode replacements, increasing maintenance costs and system downtime. The method provided in this application actively controls the shutdown of the switching transistor, preventing the FRD device from experiencing excessive overvoltage energy, thereby protecting the TVS diode connected in parallel. Therefore, the method provided in this application not only protects the FRD device but also solves the problem of existing TVS diode clamping protection schemes easily burning out due to energy overload when facing non-periodic high-energy pulses, avoiding TVS diode energy overload and reducing protection costs. Furthermore, it is worth noting that the method provided in this application only requires the existing TVS diode circuit for protecting against periodic energy, without changing the circuit structure or increasing hardware costs, to simultaneously protect against non-periodic high-energy pulses, and simultaneously protects both the FRD device and the TVS diode.

[0029] Figure 1This is a schematic flowchart illustrating a control method for an FRD device according to an example embodiment of this application. Figure 1 As shown, the control method for the FRD device provided in this embodiment includes: S101. Obtain the voltage signal across the FRD device in the circuit.

[0030] In the circuit where the FRD device is located, for example in a three-phase inverter bridge arm circuit, the two ends of the FRD device can be determined as voltage sampling points. Specifically, the sampling points can be directly connected between the positive and negative terminals of the FRD to ensure that the voltage fluctuations that the FRD experiences during actual operation can be accurately captured, including normal operating voltage and potential overvoltage pulses.

[0031] Optionally, a TVS diode is connected in parallel across the FRD device, wherein the clamping voltage of the TVS diode is less than the reverse withstand voltage threshold of the FRD device. This TVS diode clamping is mainly used to protect against periodic switching noise.

[0032] S102. If it is determined from the voltage signal that there is a transient pulse signal in the current time period and the maximum voltage value exceeds the preset voltage threshold, then determine the energy integral in the current time period.

[0033] The voltage signal across the FRD device is acquired in real time by a voltage sensor. After being processed by a signal conditioning circuit (such as filtering and amplification), the acquired voltage signal is input to the control unit (such as a microcontroller). Then, the control unit determines whether there are transient pulse signals in the voltage signal during the current time period.

[0034] In one possible implementation, if the ratio of the duration of a voltage signal greater than a preset pulse voltage threshold to the duration of the current time period is greater than a preset ratio threshold, then it is determined that a transient pulse signal exists within the current time period, wherein the aforementioned duration is a continuous and uninterrupted duration.

[0035] It is worth noting that a preset pulse voltage threshold can be set based on the reverse withstand voltage of the FRD device, for example, taking 80% of the reverse withstand voltage as the preset pulse voltage threshold. This threshold needs to be lower than the clamping voltage of the TVS diode to avoid TVS malfunction. The TVS diode is connected in parallel across the FRD device, and the clamping voltage of the TVS diode is less than the reverse withstand voltage threshold of the FRD device.

[0036] In other words, the aforementioned preset pulse voltage threshold is less than the clamping voltage of the TVS diode, and the clamping voltage of the TVS diode is less than the reverse withstand voltage threshold of the FRD device.

[0037] It is worth noting that by setting a preset pulse voltage threshold lower than the clamping voltage of the TVS diode, and under the premise that the clamping voltage of the TVS diode is lower than the reverse withstand voltage threshold of the FRD device, a multi-layered circuit protection system is formed. This hierarchical protection design allows the circuit to take corresponding protection measures according to different voltage anomalies. At the same time, it also avoids the TVS diode from malfunctioning under low voltage spikes, extending its service life. Specifically, when a voltage spike occurs in the circuit, a preliminary judgment is made based on the preset pulse voltage threshold. If the voltage exceeds the threshold but has not yet reached the clamping voltage of the TVS diode, the system can take other measures (such as adjusting the control strategy) to cope with it. Only when the voltage exceeds the clamping voltage of the TVS diode will the TVS diode conduct, discharging energy to ground, thereby protecting the FRD device from overvoltage damage.

[0038] Furthermore, because the preset pulse voltage threshold is set to be lower than the clamping voltage of the TVS diode, the TVS diode only conducts when the voltage exceeds its clamping voltage. This means that the TVS diode will not operate with every voltage spike, thereby reducing its conduction frequency and the energy surges it withstands. Reducing the conduction frequency of the TVS diode helps lower its operating temperature, improving its efficiency and reliability. At the same time, it also reduces the risk of failure that may be caused by frequent TVS diode conduction, further enhancing circuit stability.

[0039] The clamping voltage of the TVS diode is set to be lower than the reverse withstand voltage threshold of the FRD device. This ensures that when the TVS diode is turned on, the voltage across the FRD device will not exceed its reverse withstand voltage threshold, thus preventing damage to the FRD device due to reverse breakdown. This setting effectively guarantees the safe operation of the FRD device and reduces circuit failures and repair costs caused by FRD device damage.

[0040] Then, a proportional threshold is set according to the circuit's tolerance to transient pulses, for example, 5%. That is, if the duration of voltage exceeding the preset pulse voltage threshold accounts for more than 5% of the total duration of the current period, it is determined to be a transient pulse.

[0041] The aforementioned preset proportional threshold can be dynamically adjusted according to different circuit conditions and application scenarios. For example, in some circuits with low tolerance to transient pulses, a smaller proportional threshold can be set to improve detection sensitivity; while in circuits with higher tolerance, a larger proportional threshold can be set to reduce false triggering.

[0042] In another possible implementation, if the rate of change of the voltage signal in the current time period is greater than a preset rate of change threshold, then it is determined that there is a transient pulse signal in the current time period. Figure 2This is a voltage signal waveform diagram illustrated in an example embodiment of this application, such as... Figure 2 As shown, voltage signals change drastically in a very short time (such as nanoseconds to microseconds), and their rate of change is much higher than that of voltage fluctuations under normal operating conditions. Therefore, transient pulses can be distinguished from normal signals by setting a preset rate of change threshold.

[0043] In another possible implementation, if a local waveform in the voltage signal has a matching degree exceeding a preset transient pulse waveform, then a transient pulse signal is determined to exist within the current time period. Figure 3 This is a waveform diagram of a preset transient pulse waveform shown in an example embodiment of this application, such as... Figure 3 and Figure 2 As shown, there are local waveforms in the voltage signal whose matching degree with the preset transient pulse waveform exceeds the preset matching degree.

[0044] In a three-phase inverter bridge arm circuit, FRD devices may generate transient pulse overvoltages of different specific forms due to switching, motor back EMF superposition, or parasitic parameter oscillations. This step identifies transient pulses by pre-setting a transient pulse waveform template and detecting local waveforms in the voltage signal that match the template in real time, thus avoiding protection failures caused by misjudgments based on a single parameter (such as voltage change rate). Specifically, the presence of a transient pulse signal can be determined by calculating the correlation coefficient between the pre-set transient pulse waveform template and various parts of the voltage signal; alternatively, nonlinear time alignment can be used to calculate the minimum cumulative distance between the voltage signal segment and the template waveform, and then the reciprocal or normalized value of the distance can be set as the matching degree; another approach is to extract key feature parameters (such as rise time, pulse width, frequency, etc.) between the voltage signal segment and the template waveform and calculate the matching degree using weighted similarity; still another method is to transform the waveform matching problem into a binary classification problem (match / mismatch), and directly output the matching degree by training a classification model.

[0045] It is worth noting that the three possible implementation methods described above can be set individually or together, thereby constructing a detection system from the time dimension (duration), rate of change (derivative), and waveform features (template matching), respectively.

[0046] After determining the presence of a transient pulse signal within the current time period of the voltage signal, it is further possible to determine whether the maximum voltage in the voltage signal exceeds a preset voltage threshold. If the maximum voltage exceeds the preset voltage threshold, the energy integral within the current time period is determined. It is worth noting that the aforementioned preset voltage threshold is related to the reverse withstand voltage threshold of the FRD device and the clamping voltage of the TVS diode. The preset voltage threshold can be set higher than the clamping voltage of the TVS diode to prevent false triggering of the FRD protection during normal TVS operation, while being lower than the reverse withstand voltage threshold of the FRD to ensure that the FRD is not broken down before the threshold is triggered.

[0047] It is worth noting that transient pulse signals are non-periodic transient pulse signals. The term "non-periodic" is used to characterize that the transient pulse signal does not have a fixed period within the current time period.

[0048] S103. If the energy integral is greater than the preset energy integral threshold, the control chip in the control circuit will turn off the switching transistor of the branch where the FRD device is located in the next time period.

[0049] In this step, the ratio between the square of the voltage signal and the load impedance of the circuit can be integrated over the current time period to determine the energy integral mentioned above.

[0050] If the energy integral value for the current time period exceeds a preset energy integral threshold, a protection signal is triggered. This protection signal can be output to the switching transistor driver circuit via the GPIO pin of a control chip (such as the IR2110 driver chip). The driver signal goes low in the next time period (e.g., after 10μs), forcibly turning off the switching transistor. Furthermore, to prevent malfunctions, a 1ms latch is applied after the protection signal is triggered (this can be implemented using a timer), during which all voltage signal inputs are ignored. If the energy integral value for the current time period is less than or equal to the preset energy integral threshold, the switching transistor remains on.

[0051] In this embodiment, by acquiring the voltage signal across the FRD device in the circuit, if it is determined from the voltage signal that there is a transient pulse signal in the current time period and the maximum voltage value exceeds the preset voltage threshold, the energy integral in the current time period is determined. If the energy integral is greater than the preset energy integral threshold, the control chip in the control circuit will turn off the switch of the branch where the FRD device is located in the next time period, thereby effectively avoiding the problem of overvoltage failure of the FRD device and related circuits caused by non-periodic transient pulses, so as to achieve overvoltage protection for the circuit in which the FRD device is set.

[0052] In other words, existing technologies for overvoltage protection of FRD devices mainly rely on TVS diode clamping schemes. However, this scheme is primarily designed for periodic switching noise and has limited capacity to handle non-periodic transient pulse energy, easily leading to TVS diode burnout due to energy overload. The above embodiment, by acquiring the voltage signal across the FRD device in the three-phase inverter bridge arm circuit, detects the presence of transient pulse signals. When specific conditions are met (transient pulse signal with a maximum voltage exceeding a preset voltage threshold and energy integral greater than a preset energy integral threshold), the control chip in the control circuit shuts down the switch of the bridge arm containing the FRD device in the next time period. This prevents the FRD device from being subjected to excessive overvoltage energy, thereby protecting the TVS diode connected in parallel and solving the problem of TVS diode burnout under non-periodic high-energy pulses. In other words, by promptly cutting off the damage path of overvoltage energy to the FRD device, the lifespan of the FRD device and TVS diode in the three-phase inverter bridge arm circuit is effectively extended, ensuring the normal operation of the entire three-phase inverter bridge arm circuit and improving the stability and reliability of the system. Furthermore, by avoiding frequent replacement of TVS diodes, system maintenance costs and downtime can be reduced.

[0053] Figure 4 This is a schematic diagram of the structure of an electronic device according to an example embodiment of this application. For example... Figure 4 As shown, the electronic device 400 provided in this embodiment includes: a processor 401 and a memory 402; wherein: Memory 402 is used to store computer programs, and the memory may also be flash memory.

[0054] Processor 401 is used to execute the execution instructions stored in the memory to implement the various steps in the above method. For details, please refer to the relevant descriptions in the preceding method embodiments.

[0055] Alternatively, the memory 402 can be either standalone or integrated with the processor 401.

[0056] When the memory 402 is a device independent of the processor 401, the electronic device 400 may further include: Bus 403 is used to connect the memory 402 and the processor 401.

[0057] This embodiment also provides a readable storage medium storing a computer program, which, when executed by at least one processor of an electronic device, enables the electronic device to perform the methods provided in the various embodiments described above.

[0058] This embodiment also provides a program product including a computer program stored in a readable storage medium. At least one processor of an electronic device can read the computer program from the readable storage medium, and the at least one processor executes the computer program to cause the electronic device to perform the methods provided in the various embodiments described above.

[0059] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

[0060] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A control method for an FRD device, characterized in that, include: Obtain the voltage signal across the FRD device in the circuit; If, based on the voltage signal, it is determined that a transient pulse signal exists within the current time period and the maximum voltage value exceeds a preset voltage threshold, then the energy integral within the current time period is determined. If the energy integral is greater than the preset energy integral threshold, the control chip in the circuit will turn off the switching transistor of the branch where the FRD device is located in the next time period.

2. The control method for the FRD device according to claim 1, characterized in that, The step of determining the presence of a transient pulse signal within the current time period based on the voltage signal includes: If the ratio of the duration of the voltage signal greater than a preset pulse voltage threshold to the duration of the current time period is greater than a preset ratio threshold, then it is determined that there is a transient pulse signal in the current time period, wherein the duration is a continuous and uninterrupted duration.

3. The control method for the FRD device according to claim 1, characterized in that, The step of determining the presence of a transient pulse signal within the current time period based on the voltage signal includes: If the voltage change rate of the voltage signal during the current time period is greater than a preset change rate threshold, then it is determined that there is a transient pulse signal during the current time period.

4. The control method for the FRD device according to claim 1, characterized in that, The step of determining the presence of a transient pulse signal within the current time period based on the voltage signal includes: If there is a local waveform in the voltage signal whose matching degree with the preset transient pulse waveform exceeds the preset matching degree, then it is determined that the transient pulse signal exists in the current time period.

5. The control method for the FRD device according to any one of claims 1-4, characterized in that, The transient pulse signal is a non-periodic transient pulse signal, and the non-periodicity is used to characterize that the transient pulse signal does not have a fixed period within the current time period.

6. The control method for the FRD device according to claim 1, characterized in that, Determining the energy integral within the current time period includes: The ratio between the square of the voltage signal and the load impedance of the circuit is integrated during the current time period to determine the energy integral.

7. The control method for the FRD device according to claim 1, characterized in that, A TVS diode is connected in parallel across the two ends of the FRD device, wherein the clamping voltage of the TVS diode is less than the reverse withstand voltage threshold of the FRD device.

8. A three-phase inverter bridge arm circuit, characterized in that, include: FRD devices are installed on each bridge arm; The FRD device is overvoltage protected by the control method of the FRD device as described in any one of claims 1-7.

9. An electronic device, characterized in that, include: processor; as well as, Memory for storing the executable instructions of the processor; The processor is configured to execute the method of any one of claims 1 to 7 by executing the executable instructions.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1 to 7.

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