Igct overvoltage protection method, device, controller and converter system

Abstract

The application provides an IGCT overvoltage protection method, device, controller and converter system, and relates to the technical field of high-voltage direct current transmission. The method comprises the following steps: obtaining a first signal of an IGCT device power supply state in a feedback submodule and a second signal of a feedback trigger state; when the converter valve is in an operation stage, if the input du / dt of the submodule exceeds a threshold, the driving power supply is determined to be faulty according to the first signal, and the trigger circuit for triggering the IGCT device is determined to be faulty according to the second signal, a first control instruction is generated to enable a first device for executing transient voltage protection; when the converter valve is in a starting stage, if the input du / dt exceeds a second threshold or the driving power supply is determined to have no output according to the first signal, a second control instruction is generated to enable a second device for executing transient voltage protection. The above method overcomes the defect that the IGCT is mis-triggered due to the transient voltage effect of the converter valve.

Description

Technical Field

[0001] This application belongs to the field of high voltage direct current transmission technology, specifically relating to an IGCT overvoltage protection method, an IGCT overvoltage protection device, a controller, a converter system, and a machine-readable storage medium. Background Technology

[0002] The design of high-voltage DC converter valves based on IGCT devices mainly revolves around the safe operation of the IGCT devices, including drive power supply design, control and protection circuit design, and clamping circuit parameter design. Achieving the required voltage stress level is a key focus. A good voltage stress level refers to the converter valve achieving good voltage withstand capability and du / dt withstand capability.

[0003] If the IGCT device is subjected to transient voltage, a displacement current will be generated internally under the influence of high du / dt. This displacement current may cause the IGCT device to be falsely triggered, leading to the false opening of the high-voltage DC converter valve. For the high-voltage DC converter valve during startup, since the anode-cathode voltage can only be established after the IGCT drive power supply is fully established, a rapid change in the converter valve voltage will prevent the drive from quickly drawing power, putting the IGCT device at significant risk. Furthermore, during converter valve operation, if the IGCT drive power supply or drive malfunctions, a transient converter valve voltage will be applied across the IGCT device, causing it to be damaged due to its inability to withstand the voltage. Summary of the Invention

[0004] The purpose of this application is to provide an IGCT overvoltage protection method, an IGCT overvoltage protection device, a controller, a converter system, and a machine-readable storage medium to overcome the technical problem in the prior art where transient voltages acting on converter valves cause false triggering and damage to IGCT devices.

[0005] To achieve the above objectives, a first aspect of this application provides an IGCT overvoltage protection method, comprising: acquiring a first signal that feeds back the power supply status of an IGCT device within a converter valve submodule and a second signal that feeds back the trigger status of the IGCT device; when the converter valve is in operation, if the input voltage change rate of the submodule exceeds a threshold, and a fault is determined based on the first signal to be a fault in the drive power supply used to drive the IGCT device, and a fault is determined based on the second signal to be a fault in the trigger circuit used to trigger the IGCT device, then generating a first control command to enable a first device for performing transient voltage protection; when the converter valve is in startup, if the input voltage change rate exceeds a second threshold or the first signal determines that the drive power supply has no output, then generating a second control command to enable a second device for performing transient voltage protection; wherein the first threshold is less than the second threshold, and the first device and the second device are located in the bypass of the IGCT device.

[0006] In a specific embodiment of this application, the IGCT overvoltage protection method further includes: if the input voltage change rate exceeds the threshold value, and the IGCT device is successfully powered based on the first signal, then a third control command is generated to control the IGCT device to trigger protectively.

[0007] In a specific embodiment of this application, the IGCT overvoltage protection method further includes: when the converter valve is in operation, if at least one of a first trigger condition, a second trigger condition, a third trigger condition, and a fourth trigger condition is met, a fourth control command is generated to enable the second device performing transient voltage protection and lock out the submodule. The first trigger condition is: the input voltage change rate exceeds a second threshold. The second trigger condition is: a circuit fault used to feed back the second signal. The third trigger condition is: the input voltage change rate exceeds a threshold, and the drive power supply is faulty, or the control unit in the trigger circuit is faulty, or the drive circuit in the trigger circuit is faulty. The control unit is used to generate a positive trigger signal to control the IGCT device to open and to generate a reverse trigger signal to control the IGCT device to close. The drive circuit is used to open the IGCT device according to the positive trigger signal and close the IGCT device according to the reverse trigger signal. The fourth trigger condition is: there is no voltage between the anode and cathode of the IGCT device, and the converter valve has an operating voltage.

[0008] In a specific embodiment of this application, the first signal includes a drive power status signal and a voltage status signal, wherein the voltage status signal reflects the voltage status applied to the anode of the IGCT device; determining a drive power failure for driving power supply to the IGCT device based on the first signal includes: if the IGCT device loses power, determining the factors causing the IGCT device to lose power based on the timing relationship between the drive power status signal and the voltage status signal, wherein the factors are a drive power failure or a failure of the IGCT device itself.

[0009] In a specific embodiment of this application, the second signal includes a trigger feedback signal and a shutdown feedback signal; determining a trigger circuit fault for triggering the IGCT device based on the second signal includes: if at least one of the following judgment conditions is met based on the trigger feedback signal and the shutdown feedback signal, then a trigger circuit fault including a drive circuit and a control unit is determined:

[0010] Based on the trigger feedback signal, it is determined that the drive circuit has not received a positive trigger signal from the control unit for controlling the IGCT device; based on the trigger feedback signal, it is determined that the positive trigger signal processed by the drive circuit has not been successfully applied between the gate and cathode of the IGCT device; based on the shutdown feedback signal, it is determined that the drive circuit has not received a reverse trigger signal from the control unit; based on the shutdown feedback signal, it is determined that the reverse trigger signal processed by the drive circuit has not been successfully applied between the gate and cathode of the IGCT device.

[0011] In a specific embodiment of this application, the IGCT overvoltage protection method further includes: if a fault is determined in the body of the IGCT device according to the first signal, then controlling the IGCT device to open; if a fault is determined in the drive circuit of the trigger circuit according to the second signal, then controlling the IGCT device to close and controlling the gate clamping circuit connected to the IGCT device to disconnect.

[0012] In a specific embodiment of this application, generating a second control command to enable a second device for performing transient voltage protection includes: generating a second control command to close the target bypass of the submodule to isolate the submodule; wherein the target bypass is provided with a second device.

[0013] A second aspect of this application provides an IGCT overvoltage protection device, comprising: a first module, configured to acquire a first signal for feedback of the power supply status of an IGCT device within a converter valve submodule and a second signal for feedback of the trigger status of the IGCT device; and a second module, configured to, when the converter valve is in operation, determine whether the input voltage change rate of the submodule exceeds a threshold, and, based on the first signal, determine whether the drive power supply for driving the IGCT device is faulty, and, based on the second signal, determine whether the trigger circuit for triggering the IGCT device is faulty. If the input voltage change rate of the submodule exceeds a threshold, and based on the first signal, the drive power supply for driving the IGCT device is faulty, the second module determines whether the trigger circuit for triggering the IGCT device is faulty. If the drive power supply for the IGCT device fails, and the trigger circuit for triggering the IGCT device is determined to be faulty according to the second signal, a first control command is generated to enable the first device for performing transient voltage protection; and if the commutation valve is in the startup phase, it is determined whether the input voltage change rate exceeds a two-stage threshold and whether the drive power supply has an output according to the first signal. If the input voltage change rate exceeds the two-stage threshold or the drive power supply has no output according to the first signal, a second control command is generated to enable the second device for performing transient voltage protection; wherein the first-stage threshold is less than the second-stage threshold, and the first device and the second device are located in the bypass of the IGCT device.

[0014] A third aspect of this application provides a controller including a memory and a processor. The memory is configured to store instructions, and the processor is configured to retrieve the instructions from the memory and, when executing the instructions, to implement the IGCT overvoltage protection method according to a first aspect of this application.

[0015] A fourth aspect of this application provides a converter system including a converter submodule based on an IGCT device and a controller, wherein the submodule is electrically connected to the controller, and the controller is used to execute the IGCT overvoltage protection method described in the first aspect of this application.

[0016] In a specific embodiment of this application, the converter system further includes a first MOV device, a first device, a Zener diode, and a second device; the anode of the IGCT device is connected to the first end of the first MOV device, the first end of the first device, and the first end of the second device, respectively; the cathode of the Zener diode is connected to the second end of the first MOV device; and the cathode of the IGCT device is connected to the positive electrode of the Zener diode, the second end of the first device, and the second end of the second device, respectively.

[0017] In a specific embodiment of this application, the first device is a transition device, which switches from a forward blocking state to a forward conducting state when its operating voltage rises to a predefined transition voltage.

[0018] In a specific embodiment of this application, the transition device is a bidirectional transition thyristor or a second MOV device.

[0019] In specific embodiments of the application, the type of the second device includes at least one of a bypass switch, a bypass thyristor, an IGBT device, and a transition diode.

[0020] The fifth aspect of this application provides a machine-readable storage medium storing instructions that, when executed by a processor, configure the processor to perform the IGCT overvoltage protection method according to the first aspect of this application.

[0021] Through the above technical solution, a transient voltage protection strategy for the submodule operation and startup phases is formulated based on the first signal reflecting the power supply status of the IGCT device, the second signal reflecting the triggering status of the IGCT device, and the preset du / dt first and second thresholds. This overcomes the problem of IGCT device false triggering caused by displacement current of the IGCT device under the action of transient voltage of the converter valve, avoids damage to the IGCT device caused by transient voltage, and improves the operational reliability of the converter valve.

[0022] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings:

[0024] Figure 1 The diagram shown is a first flowchart of an IGCT overvoltage protection method according to an embodiment of this application.

[0025] Figure 2 The diagram shown is a timing relationship diagram between the drive power supply status signal and the voltage status signal according to an embodiment of this application;

[0026] Figure 3 The diagram shown is a second flowchart of an IGCT overvoltage protection method according to an embodiment of this application.

[0027] Figure 4 The diagram shown is a schematic representation of some protection strategies according to embodiments of this application;

[0028] Figure 5 The diagram shown is a third flowchart of an IGCT overvoltage protection method according to an embodiment of this application.

[0029] Figure 6 The diagram shown is a fourth flowchart of an IGCT overvoltage protection method according to an embodiment of this application.

[0030] Figure 7 The diagram shown is an internal structure diagram of a computer device according to an embodiment of this application;

[0031] Figure 8 The diagram shown is a schematic diagram of a converter system according to an embodiment of this application. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0033] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0034] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0035] To overcome the technical problem of false triggering and damage of IGCT devices caused by transient voltage in high-voltage DC converter valves based on IGCT devices (referred to as converter valves in the embodiments of this application), various solutions have been proposed in the prior art. Examples are illustrated below.

[0036] In one existing technology, drawing on the overvoltage protection design of traditional thyristors, an RC circuit is connected in parallel across the two ends of the IGCT device. The principle of the capacitor in the RC circuit to mitigate voltage surges is used to suppress du / dt. It has the advantages of simple structure and low cost, and is suitable for most medium and low voltage scenarios. It can effectively suppress displacement current and prevent false triggering. The disadvantage is that in high frequency or high voltage scenarios, the charging and discharging of the capacitor may introduce additional losses.

[0037] In another existing technology, a capacitor is connected in parallel between the gate and the cathode to bypass the displacement current caused by du / dt to the cathode, thus preventing the thyristor from being triggered. The advantage of this approach is that it precisely suppresses the displacement current, reducing the risk of false triggering of the thyristor. The disadvantage is that the capacitor value needs to be precisely matched; an improper value may affect the normal trigger signal, and accurately determining the capacitor value is one of the challenges. Furthermore, for a thyristor with a specific capacitor value, it is difficult to apply it to diverse high-voltage direct current transmission scenarios.

[0038] Another existing technology employs intelligent detection and dynamic protection, dynamically adjusting the overvoltage protection threshold by real-time detection of the du / dt value. The advantages of this approach are strong adaptability; for example, the protection threshold decreases as du / dt increases, making it suitable for complex scenarios such as high-voltage DC converter valves. The disadvantages are the need for additional detection circuitry, increasing system complexity, and potential response delays that could affect the real-time performance of overvoltage protection.

[0039] Unlike the prior art, this application provides an IGCT overvoltage protection method that achieves overvoltage protection for IGCT devices through the following technical approach: acquiring a first signal indicating the power supply status of the IGCT device within the feedback converter valve submodule and a second signal indicating the trigger status of the IGCT device; when the converter valve is in operation, if the input voltage change rate of the submodule exceeds a threshold, and the drive power supply for powering the IGCT device is determined to be faulty based on the first signal, and the trigger circuit for triggering the IGCT device is determined to be faulty based on the second signal, then a first control command is generated to activate a first device for transient voltage protection; when the converter valve is in startup, if the input voltage change rate exceeds a second threshold or the drive power supply is determined to have no output based on the first signal, then a second control command is generated to activate a second device for transient voltage protection. The first threshold is less than the second threshold. Both the first and second devices are located in the bypass circuit of the IGCT device, i.e., both the first and second devices are bypass devices for the IGCT device.

[0040] It is important to understand that the drive power supply used to power the IGCT device can also be called the submodule power supply or the drive power supply. The trigger circuit for triggering the IGCT device refers to the control unit that generates a positive trigger signal acting on the gate of the IGCT device and a reverse trigger signal (turn-off signal) acting on the cathode of the IGCT device, and the drive circuit that receives and processes the positive trigger signal and the turn-off signal to drive the IGCT device. Unlike valve control and pole control outside the submodule, the control unit described above can also be called the central control unit. A trigger circuit failure can be a central control unit failure or a drive circuit failure. When multiple drive circuits exist, a drive circuit failure refers to the simultaneous failure of all multiple drive circuits. For example, when the IGCT device uses dual-path drive, the drive circuit failure refers to the simultaneous failure of both drive paths.

[0041] It is important to understand that the first threshold is less than the second threshold. The first and second thresholds refer to different levels of du / dt protection thresholds. Exceeding the first threshold means exceeding the first limit, and exceeding the second threshold means exceeding the second limit. The first and second thresholds refer to different du / dt fluctuation ranges.

[0042] In the above-mentioned technical approach of this application, the coordinated monitoring of the first signal and the second signal is used as the basis. The first signal feeds back the power supply status of the IGCT device, and the second signal feeds back the trigger status of the IGCT device. Based on this, and combined with the operating status of the IGCT device based on the first and second signals and the two du / dt thresholds, a transient voltage protection strategy for the start-up and operation phases of the converter valve is formulated. The transient voltage protection strategy is also called the du / dt over-limit protection strategy. It overcomes the problem of false triggering of the IGCT device caused by the displacement current of the IGCT device under the action of transient voltage of the converter valve, and avoids damage to the IGCT device caused by transient voltage.

[0043] Meanwhile, the transient voltage protection strategies differ between the start-up and operation phases of the converter valve, specifically differentiating the du / dt over-limit protection strategies for these two operating conditions. The aforementioned two different du / dt over-limit protection strategies correspond to the du / dt over-limit protection trigger conditions under each condition. Specifically, during the converter valve start-up phase, transient voltage protection based on the second device is triggered when du / dt exceeds the second stage limit (input voltage change rate exceeds the second stage threshold), and when there is no output from the drive power supply. During the converter valve operation phase, the condition for triggering transient voltage protection based on the first device includes at least a du / dt first stage limit exceedance (input voltage change rate exceeds the first stage threshold). It is evident that the du / dt over-limit protection strategies and strengths differ between the two operating conditions. In practical applications, this difference can prevent frequent on / off switching of the converter valve caused by a "one-size-fits-all" approach.

[0044] Furthermore, unlike the aforementioned existing technologies, it effectively addresses the combined risks caused by du / dt over-limit and drive power supply failure, thereby improving the reliability of the converter valve.

[0045] Figure 1 The diagram shown is a schematic flowchart of the IGCT overvoltage protection method provided in a specific embodiment of this application. Figure 1 As shown, the IGCT overvoltage protection method provided in Embodiment 1 includes the following steps 202 to 204.

[0046] Step 202: Obtain a first signal indicating the power supply status of the IGCT device within the feedback converter valve submodule and a second signal indicating the trigger status of the IGCT device.

[0047] The first signal reflects the power supply status of the IGCT device. In some embodiments, the first signal includes at least a drive power status signal and a voltage status signal, wherein the voltage status signal reflects the voltage status applied to the anode of the IGCT device. The voltage applied to the anode of the IGCT device is also called the IGCT device drive voltage, and the voltage status type applied to the anode of the IGCT device can be minimum voltage, normal voltage, threshold protection voltage, and breakdown voltage.

[0048] In some embodiments, the first signal includes a drive power supply status signal, a voltage status signal, and a power harvesting signal. The power harvesting signal is fed back to the operating status of the online power harvesting circuit of the drive power supply. The online power harvesting circuit is typically a high-potential, high-capacity online power harvesting circuit, which usually includes a power harvesting capacitor, etc.

[0049] In some embodiments, the second signal includes a trigger feedback signal and a shutdown feedback signal. The trigger feedback signal is used to provide feedback on whether the drive circuit for driving the IGCT device has received a positive trigger signal from the control unit for controlling the IGCT device to turn on, and to provide feedback on whether the gate-to-cathode area of ​​the IGCT device has been successfully processed by the drive circuit. The shutdown feedback signal is used to provide feedback on whether the drive circuit has received a reverse trigger signal from the control unit for controlling the IGCT device to turn off, and to provide feedback on whether the gate-to-cathode area of ​​the IGCT device has been successfully processed by the drive circuit.

[0050] Step 204, perform the following overvoltage protection operation:

[0051] The first operation: When the converter valve is in operation, if the input voltage change rate of the converter valve submodule exceeds a threshold, and the drive power supply for powering the IGCT device is determined to be faulty according to the first signal, and the trigger circuit for triggering the IGCT device is determined to be faulty according to the second signal, then a first control command is generated to enable the first device to perform transient voltage protection.

[0052] The second operation: When the converter valve is in the start-up phase, if the input voltage change rate exceeds the second threshold as mentioned above, or if the first signal determines that the drive power supply has no output as mentioned above, a second control command is generated to enable the second device to perform transient voltage protection.

[0053] Specifically, in this application, the first-stage threshold and the second-stage threshold are set based on the tolerance capability of the IGCT device and the extreme operating conditions of the converter valve. For example, after determining the application scenario of the converter valve, the tolerance capability of the selected IGCT device or the IGCT device that meets the design requirements and the extreme operating conditions under that application scenario are set. It should be understood that, in order to improve the accuracy of the first-stage threshold and the second-stage threshold, it is not limited to the two considerations mentioned above, that is, it is not limited to only considering the tolerance capability of the IGCT device and the extreme operating conditions of the converter valve. Other considerations can also be introduced based on experience or with theoretical support, but without departing from the protection scope of this application.

[0054] In some embodiments, when the converter valve is in operation, the specific steps of generating a first control command to enable the first device to perform transient voltage protection include:

[0055] Step a1: Generate a first control command to enable a first device connected in parallel with the IGCT device, the first device being a transient voltage protection device.

[0056] The transient voltage protection device can be an existing bypass overvoltage protection device for IGCT devices, or it can be an overvoltage protection device that is commonly used in overvoltage protection of ordinary thyristors, and it is added to the converter submodule so that it can be activated after the first control command is generated.

[0057] In some embodiments, when the converter valve is in operation, the specific steps of generating a first control command to enable the first device to perform transient voltage protection include:

[0058] Step b1: Generate a first control command to enable the first device connected in parallel with the IGCT device. When the operating voltage of the first device rises to a predefined breakover voltage, the first device changes from a forward blocking state to a forward conducting state.

[0059] Because the values ​​of the du / dt threshold may differ for different application scenarios, unlike the overvoltage protection device connected to the IGCT device in a typical embodiment, this device, by adopting a first device based on the transition voltage when the operating state changes, can adapt to transient voltage protection requirements when the input voltage change rate exceeds the du / dt threshold.

[0060] As an example, the first device is a transition thyristor or MOV device.

[0061] In some embodiments, the specific steps of generating a second control command to enable a second device for performing transient voltage protection when the converter valve is in the startup phase include:

[0062] Step c1: Generate a second control command to close the target bypass of the converter valve submodule to isolate the submodule. A second device is installed in the target bypass.

[0063] As an example, the second device can be one of a bypass switch, a bypass thyristor, an IGBT device, and a transition diode.

[0064] Based on the above-mentioned target bypass settings, step c1 may include:

[0065] Step c11 generates a second control command, which causes the target bypass of the submodule to close immediately, thereby achieving the isolation of the submodule.

[0066] In some embodiments, the first signal includes a drive power status signal and a voltage status signal. The specific steps for determining a drive power failure for supplying power to the IGCT device based on the first signal include:

[0067] Step d1: If the IGCT device loses power, the factor causing the IGCT device to lose power is determined based on the timing relationship between the drive power status signal and the voltage status signal. This factor is either a drive power failure or an IGCT device failure.

[0068] Specifically, the steps for determining the factors causing the power failure of the IGCT device based on the timing relationship between the drive power status signal and the voltage status signal include: if the voltage status signal indicates that the anode voltage of the IGCT device has dropped, and after the anode voltage of the IGCT device drops, the drive power status signal indicates that the output voltage of the drive power supply has dropped, then the factor causing the power failure of the IGCT device is determined to be a fault in the IGCT device itself; if the drive power status signal indicates that the output voltage of the drive power supply has dropped, and the voltage status signal indicates that after the output voltage of the drive power supply has dropped, the anode voltage of the IGCT device is normal, then the factor causing the power failure of the IGCT device is determined to be a fault in the drive power supply.

[0069] Combination Figure 2 As shown, according to the working principle of the submodule, when the IGCT device voltage is generated, the voltage synchronization state of the IGCT device can be identified based on the voltage state signal. However, the capacitor voltage of the submodule cannot change abruptly. Therefore, during the startup phase, it is generated along with the voltage state signal of the IGCT device. When the voltage reaches the threshold, the drive power supply state signal also changes accordingly. When the voltage suddenly drops, the voltage state signal of the IGCT device changes immediately, while the submodule capacitor voltage cannot change immediately. However, due to the lack of energy replenishment, its voltage state also decreases, and the drive power supply state signal will also remain for a period of time with the presence of the submodule capacitor voltage, until the drive power supply's own capacitor voltage can no longer be maintained. This demonstrates... Figure 2 The timing relationship is shown. When the voltage of the IGCT device suddenly drops, or when the voltage of the IGCT device itself drops suddenly due to a fault such as breakdown, it will be reflected in the submodule capacitor voltage or the drive power supply status signal. Conversely, if the voltage driving the IGCT device is normal, the corresponding IGCT device voltage status signal and the submodule capacitor voltage status will also be normal.

[0070] As an example, power loss in an IGCT device can be caused by factors such as a drive power supply failure or a fault in the IGCT device itself. The drive power supply failure and the IGCT device itself can be distinguished by comparing the timing relationship between the drive power supply status signal and the voltage status signal. A drive power supply failure may manifest as severe electromagnetic interference or insufficient peak power.

[0071] In some embodiments, if it is determined from the drive power supply status signal that there is no voltage at the output terminal of the drive power supply, then it can be determined that the drive power supply has no output.

[0072] In some embodiments, the second signal includes a trigger feedback signal and a shutdown feedback signal. The specific steps for determining a trigger circuit fault for triggering the IGCT device based on the trigger feedback signal and the shutdown feedback signal include:

[0073] Step e1: If at least one of the following judgment conditions is met based on the trigger feedback signal and the shutdown feedback signal, then a trigger circuit fault, including the drive circuit and the control unit, is determined to be present:

[0074] The trigger feedback signal indicates that the drive circuit has not received a positive trigger signal from the control unit.

[0075] The positive trigger signal after the gate-cathode of the IGCT device was not successfully processed by the drive circuit is determined based on the trigger feedback signal;

[0076] The shutdown feedback signal indicates that the drive circuit did not receive the reverse trigger signal from the control unit.

[0077] The reverse trigger signal of the IGCT device after the gate-cathode interface was not successfully processed by the drive circuit is determined based on the turn-off feedback signal.

[0078] It is important to understand that the forward and reverse trigger signals are applied between the gate and cathode to control the IGCT device to turn on via the forward trigger signal or to control the IGCT device to turn off via the reverse trigger signal. Therefore, a forward trigger signal that has not been successfully processed by the drive circuit between the gate and cathode refers to the gate-cathode failing to receive the processed forward trigger signal, and a reverse trigger signal that has not been successfully processed by the drive circuit between the gate and cathode refers to the gate-cathode failing to receive the processed reverse trigger signal. Successful reception of the forward trigger signal by the gate-cathode indicates that the current for turning on the IGCT device has been successfully sent to the IGCT device. Successful reception of the reverse trigger signal by the gate-cathode indicates that the current for turning off the IGCT device has been successfully sent to the IGCT device.

[0079] like Figure 3 and Figure 4 As shown, the difference between the IGCT overvoltage protection method provided in Embodiment 2 of this application and other embodiments of this application is that the overvoltage protection operation performed in step 204 further includes: a third operation.

[0080] The third operation refers to: if the input voltage change rate exceeds a threshold and the IGCT device is successfully powered according to the first signal, a third control command is generated to control the IGCT device to trigger protectively.

[0081] In the second embodiment described above, the triggering condition for the protective triggering of the IGCT device is: the input voltage change rate exceeds a threshold, and the IGCT device can successfully extract power, meaning the drive circuit still has an extraction voltage. As mentioned earlier, the triggering condition comprehensively considers the du / dt over-limit situation and the extraction state of the IGCT device to generate a control strategy to cope with the transient voltage of the converter valve. This control strategy differs from the first operation described above. One of the triggering conditions for the first operation is also that the input voltage change rate exceeds a threshold, but when the IGCT device still has an extraction voltage, transient voltage protection is not triggered. The reason is that when the IGCT device still has an extraction voltage, the impact of the transient voltage of the converter valve on the safety of the IGCT device is lower than when the drive power supply and trigger circuit fail simultaneously. It can be seen that based on the differentiated operating states of the IGCT, the corresponding control strategy and protection strength are differentiated. In practical applications, this avoids the phenomenon of frequent on / off switching of the converter valve caused by a "one-size-fits-all" approach, thus improving the operational reliability of the converter valve.

[0082] In one comparative example, based on a predefined protective trigger voltage, if the input voltage of the submodule exceeds the protective trigger voltage, the IGCT device is controlled to trigger protectively, i.e., the IGCT device is controlled to open to prevent damage from overvoltage. Unlike the aforementioned comparative example, Example 2 is an IGCT device protective trigger based on du / dt first-stage over-limit start-up. This avoids potential damage to the IGCT device that might result from failure to implement protective triggering when the input du / dt first stage of the submodule exceeds the limit, thereby improving the operational reliability of the converter valve.

[0083] The third operation described above can serve as a supplement to the comparative example above. By combining du / dt and protective trigger voltage, it strengthens overvoltage protection for IGCT devices and improves the operational reliability of the converter valve.

[0084] Combination Figure 4 and Figure 5 As shown, the IGCT overvoltage protection method provided in Embodiment 3 of this application differs from the above embodiments in that the overvoltage protection operation performed in step 204 further includes a fourth operation.

[0085] The fourth operation refers to: when the converter valve is in operation, if at least one of the first triggering condition, the second triggering condition, the third triggering condition, and the fourth triggering condition is met, a fourth control command is generated to enable the second device to perform transient voltage protection and lock out the submodule.

[0086] The first triggering condition is: the input voltage change rate exceeds a second threshold. The second triggering condition is: a circuit fault used to feed back the second signal. The third triggering condition is: the input voltage change rate exceeds a first threshold, and there is a fault in the drive power supply, the control unit in the triggering circuit, or the drive circuit in the triggering circuit. The fourth triggering condition is: there is no voltage between the anode and cathode of the IGCT device, and the commutation valve has an operating voltage.

[0087] A circuit fault used for feedback of the second signal refers to: after the control unit issues a positive trigger signal, the acquired second signal lacks a trigger feedback signal, or the trigger feedback signal lacks at least a signal indicating the reception status of the positive trigger signal issued by the control unit by the feedback drive circuit, or a signal indicating the status of the positive trigger signal after the gate-to-cathode area of ​​the IGCT device has been processed by the drive circuit; and / or; after the control unit issues a reverse trigger signal, the acquired second signal lacks an interruption feedback signal, or the interruption feedback signal lacks at least a signal indicating the reception status of the reverse trigger signal issued by the control unit by the feedback drive circuit, or a signal indicating the status of the reverse trigger signal after the gate-to-cathode area of ​​the IGCT device has been processed by the drive circuit. The trigger feedback signal is used at least to determine whether the drive circuit has received a positive trigger signal and whether the gate-to-cathode area of ​​the IGCT device has been successfully processed by the drive circuit. The interruption feedback signal is used at least to determine whether the drive circuit has received a reverse trigger signal and whether the gate-to-cathode area of ​​the IGCT device has been successfully processed by the drive circuit.

[0088] In the above embodiment three, a fourth operation, distinct from the first to third operations, is proposed. Specifically, unlike the second operation, a lockout of the submodule is added. This is because, during the converter valve operation phase, when the input voltage change rate exceeds the second threshold, or when a circuit fault occurs in the feedback second signal, the transient voltage of the converter valve has a more severe impact on the safety of the IGCT device. Therefore, based on the differentiated IGCT operating states, corresponding control strategies and protection strengths are differentiated. In practical applications, this avoids the phenomenon of frequent on / off switching of the converter valve caused by a "one-size-fits-all" approach, improving the operational reliability of the converter valve.

[0089] like Figure 6 As shown, the IGCT overvoltage protection method provided in Embodiment 4 of this application differs from the above embodiments in that the overvoltage protection operation performed in step 204 further includes:

[0090] If a fault is determined in the IGCT device itself based on the first signal, the following first fault protection scheme is executed: control the IGCT device to open;

[0091] If a fault is determined in the drive circuit of the trigger circuit based on the second signal, the following second fault protection scheme is executed: control the IGCT device to shut down and control the gate clamping circuit connected to the IGCT device to disconnect.

[0092] Analysis of the first fault protection scheme for IGCT device failure and the second fault protection scheme for drive circuit failure reveals that the protection scheme for IGCT device failure differs from that for drive circuit failure. This is because, among the various faults in the converter valve submodule, drive power supply failure and drive circuit failure have the most severe impact. This differentiated fault-tolerant operation mechanism enhances the protection capability against submodule failures and improves the operational reliability of the converter valve.

[0093] The protection principle of the above-mentioned overvoltage protection strategy for drive circuit faults is as follows: by turning off the IGCT device and disconnecting the gate clamping circuit of the IGCT device, a current discharge path can be generated to prevent overcurrent damage caused by the IGCT device being turned on by mistake.

[0094] In an improved embodiment, the first fault protection scheme further includes: before the control submodule is turned off, blocking the positive trigger signal output from the trigger circuit to the gate of the IGCT device for turning on the IGCT device and blocking the reverse trigger signal output to the cathode of the IGCT device for turning off the IGCT device, and performing a judgment on whether to generate a control command for triggering a protection action. The protection action is to activate the first device for performing transient voltage protection, or activate the second device for performing transient voltage protection, or protectively trigger the IGCT device, or activate the second device for performing transient voltage protection and lock out the submodule. That is, performing a judgment on whether to generate the above-mentioned first to fourth control commands. It should be understood that in the first fault protection scheme, which of the above-mentioned first to fourth operations is triggered is determined based on whether the triggering conditions of each operation are met.

[0095] In the above improved embodiment, in order to implement overvoltage protection for the IGCT device under fault conditions, the first fault protection scheme initiates two protections for the IGCT device. The first protection is to open the IGCT device, and the second protection is a protection based on control commands. This avoids the high voltage breakdown phenomenon that may occur in the IGCT device when the submodule is in the off state. By blocking the gate cathode pulse of the IGCT device and the second protection, the possible short circuit current is blocked, thereby improving the operational reliability of the converter valve.

[0096] In some embodiments, the process of determining an IGCT device body fault based on the first signal is described in step d1 above.

[0097] In some embodiments, the specific steps for determining a drive circuit fault based on the second signal include:

[0098] Step f1: If at least one of the following judgment conditions is met based on the trigger feedback signal and the turn-off feedback signal, then the drive circuit is determined to be faulty:

[0099] When the control unit sends a positive trigger signal, it is determined from the trigger feedback signal that the gate of the IGCT device has not successfully received the positive trigger signal processed by the drive circuit.

[0100] When the control unit issues a reverse trigger signal, the cathode of the IGCT device is determined to have failed to receive the reverse trigger signal processed by the drive circuit based on the shutdown feedback signal.

[0101] In some embodiments, the fault of the drive circuit can also be determined based on the monitoring feedback for the drive circuit included in the second signal.

[0102] In some embodiments, when there are multiple drive circuits, if one or more of the drive circuits are determined to be faulty based on the second signal, the second fault protection scheme further includes: locking out the drive circuits that have not experienced a fault. By locking out the drive circuits that have not experienced a fault, they are prevented from suffering du / dt damage.

[0103] Corresponding to the IGCT overvoltage protection methods in the above embodiments, this application also provides an IGCT overvoltage protection device, which includes a first module and a second module.

[0104] The first module is used to acquire a first signal indicating the power supply status of the IGCT device within the feedback converter valve submodule and a second signal indicating the trigger status of the IGCT device.

[0105] The second module is configured to, when the converter valve is in operation, generate a first control command to enable the first device for performing transient voltage protection if the input voltage change rate of the submodule exceeds a threshold, and a fault is determined based on the first signal to supply power to the IGCT device, and a fault is determined based on the second signal to trigger the IGCT device; and when the converter valve is in startup, generate a second control command to enable the second device for performing transient voltage protection if the input voltage change rate exceeds a second threshold or the first signal determines that the drive power supply has no output.

[0106] In this configuration, one threshold is less than the second threshold, and the first and second devices are located in the bypass of the IGCT device.

[0107] As an embodiment of this application, the IGCT overvoltage protection device can achieve the following: Figure 1 The embodiments shown and other related method embodiments in this application. The process by which each module in the IGCT overvoltage protection device provided in this application implements its respective function can be specifically referred to the foregoing. Figure 1 The descriptions of the embodiments shown and other related method embodiments are not repeated here.

[0108] It should be noted that the information interaction and execution process between the above modules are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, which will not be repeated here.

[0109] The IGCT overvoltage protection device includes a processor and a memory. The first module and the second module are both stored in the memory as program units, and the processor executes the program modules stored in the memory to implement the corresponding functions.

[0110] The processor contains a kernel, which retrieves the corresponding program unit from memory. One or more kernels can be configured, and the IGCT overvoltage protection method described in the above embodiments can be implemented by adjusting the kernel parameters.

[0111] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0112] This application provides a machine-readable storage medium storing a program that, when executed by a processor, implements the above-described IGCT overvoltage protection method.

[0113] This application provides a processor for running a program, wherein the program executes the above-described IGCT overvoltage protection method during runtime.

[0114] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 7As shown, the computer device includes a processor A01, a network interface A02, a display screen A04, an input device A05, and a memory (not shown) connected via a system bus. The processor A01 provides computing and control capabilities. The memory includes internal memory A03 and a non-volatile storage medium A06. The non-volatile storage medium A06 stores an operating system B01 and a computer program B02. The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 stored in the non-volatile storage medium A06. The network interface A02 is used for communication with external terminals via a network connection. When the computer program is executed by the processor A01, it implements an IGCT overvoltage protection method. The display screen A04 can be a liquid crystal display (LCD) or an e-ink display. The input device A05 can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0115] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0116] In one embodiment, the IGCT overvoltage protection device provided in this application can be implemented as a computer program, which can be implemented in the form of, for example... Figure 7 The computer device shown operates on this device. The computer device's memory can store various program modules that constitute the IGCT overvoltage protection device, such as a first module and a second module. The computer program composed of these program modules causes the processor to execute the steps in the IGCT overvoltage protection methods of the various embodiments of this application described in this specification.

[0117] This application provides an apparatus including a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it implements the IGCT overvoltage protection method described in the above method embodiments.

[0118] This application also provides a computer program product that, when executed on a data processing device, is adapted to execute a program that initializes the IGCT overvoltage protection method steps included in the above-described method embodiments.

[0119] This application also provides a controller, including a memory and a processor. The memory is used to store instructions, and the processor is used to call the instructions from the memory and to implement the above-described IGCT overvoltage protection method when executing the instructions.

[0120] This application provides a converter system, including a converter submodule based on an IGCT device and the aforementioned controller, wherein the converter submodule is electrically connected to the controller.

[0121] In some embodiments, the converter system further includes a first MOV device, a first device, a Zener diode, and a second device; the anode of the IGCT device is connected to the first end of the MOV device, the first end of the first device, and the first end of the second device, respectively; the cathode of the Zener diode is connected to the second end of the first MOV device; and the cathode of the IGCT device is connected to the positive electrode of the Zener diode, the second end of the first device, and the second end of the second device, respectively.

[0122] In one specific embodiment, the first device is a transition device, which switches from a forward blocking state to a forward conducting state when its operating voltage rises to a predefined transition voltage.

[0123] For example, the transition device may be a transition thyristor or a second MOV device.

[0124] In one specific embodiment, the type of the second device includes at least one of the following: a bypass switch, a bypass thyristor, an IGBT device, and a transition diode.

[0125] Combination Figure 8 As shown, in a specific application example, the first device adopts the following... Figure 8 The bidirectional thyristor shown, the second device adopts as follows Figure 8 The bypass switch shown.

[0126] Combination Figure 8As shown in the above application example, the overvoltage protection circuit for the IGCT device includes an active overvoltage protection execution circuit triggered by a first control command, a second control command, and a fourth control command, as well as a passive overvoltage protection execution circuit. The passive overvoltage protection execution circuit includes an MOV device and a Zener diode, which are connected in series in a bypass circuit of the IGCT device. Specifically, the overvoltage protection process of the active overvoltage protection execution circuit is described as follows: First, the current direction is determined based on the current measuring coil. Then, based on the triggering of active protection, the bidirectional turnaround thyristor (shown in the diagram) or the bypass switch is triggered. Specifically, the first control command triggers the bidirectional turnaround thyristor to activate, and the second and fourth control commands trigger the bypass switch to close. The passive overvoltage protection process of the passive overvoltage protection execution circuit is described as follows: If the active overvoltage protection fails, and the input voltage of the current submodule is greater than a first threshold (e.g., the input voltage is still very high), the bypass switch is driven to operate through the voltage division of the MOV device and the Zener diode, thus achieving passive overvoltage protection.

[0127] Figure 8 In this circuit, the current measuring coil is connected to the anode of the IGCT device, i.e., the electrical port of the submodule, to measure the direction of the current flowing into the IGCT device.

[0128] For example, if the active protection action is active and the bidirectional switching thyristor is triggered for a first preset time, such as 3ms, the bypass switch in the figure is actively triggered, so that the current is transferred from the bidirectional switching thyristor to the bypass switch.

[0129] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0130] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations 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, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0131] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0132] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0133] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0134] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, like read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0135] Computer-readable media include both permanent and non-permanent, removable and non-removable media, which can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0136] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0137] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. An overvoltage protection method for an IGCT, characterized in that, include: Acquire a first signal that provides feedback on the power supply status of the IGCT device within the converter valve submodule and a second signal that provides feedback on the trigger status of the IGCT device; When the converter valve is in operation, if the input voltage change rate of the submodule exceeds a threshold, and a drive power supply failure is determined according to the first signal, and a trigger circuit failure is determined according to the second signal, then a first control command is generated to enable the first device to perform transient voltage protection. When the converter valve is in the start-up phase, if the input voltage change rate exceeds the second threshold or if it is determined from the first signal that the drive power supply has no output, a second control command is generated to enable the second device to perform transient voltage protection. Wherein, the first threshold is less than the second threshold, and the first device and the second device are located in the bypass of the IGCT device.

2. The IGCT overvoltage protection method according to claim 1, characterized in that, Also includes: If the rate of change of the input voltage exceeds the threshold value, and the first signal determines that the IGCT device has successfully gained power, a third control command is generated to control the protective triggering of the IGCT device.

3. The IGCT overvoltage protection method according to claim 1, characterized in that, Also includes: When the converter valve is in operation, if at least one of the first triggering condition, the second triggering condition, the third triggering condition, and the fourth triggering condition is met, a fourth control command is generated to enable the second device to perform transient voltage protection and lock out the submodule. The first triggering condition is: the rate of change of the input voltage exceeds a second threshold. The second triggering condition is a circuit fault used to provide feedback on the second signal; The third triggering condition is as follows: the input voltage change rate exceeds a threshold, and the drive power supply fails, or the control unit in the triggering circuit fails, or the drive circuit in the triggering circuit fails. The control unit is used to generate a positive trigger signal to control the IGCT device to turn on and to generate a reverse trigger signal to control the IGCT device to turn off. The drive circuit is used to turn on the IGCT device according to the positive trigger signal and to turn off the IGCT device according to the reverse trigger signal. The fourth triggering condition is that there is no voltage between the anode and cathode of the IGCT device, and the converter valve has an operating voltage.

4. The IGCT overvoltage protection method according to claim 1, characterized in that, The first signal includes a drive power status signal and a voltage status signal, the voltage status signal reflecting the voltage status applied to the anode of the IGCT device; determining a drive power supply fault for driving the IGCT device based on the first signal includes: If the IGCT device loses power, the factors causing the power loss of the IGCT device are determined based on the timing relationship between the drive power status signal and the voltage status signal. The factors are either drive power failure or IGCT device failure.

5. The IGCT overvoltage protection method according to claim 1, characterized in that, The second signal includes a trigger feedback signal and a turn-off feedback signal; Determining a fault in the trigger circuit used to trigger the IGCT device based on the second signal includes: If at least one of the following conditions is met based on the trigger feedback signal and the shutdown feedback signal, then a trigger circuit including the drive circuit and the control unit is determined to be faulty: Based on the trigger feedback signal, it is determined that the drive circuit has not received a positive trigger signal from the control unit; The positive trigger signal after the driving circuit processing was not successfully applied between the gate and cathode of the IGCT device, as determined by the trigger feedback signal. Based on the shutdown feedback signal, it is determined that the drive circuit has not received the reverse trigger signal from the control unit; The reverse trigger signal after the drive circuit processing was not successfully applied between the gate and cathode of the IGCT device is determined based on the shutdown feedback signal.

6. The IGCT overvoltage protection method according to any one of claims 1 to 5, characterized in that, Also includes: If a fault is determined in the IGCT device based on the first signal, then the IGCT device is controlled to open. If a fault is determined in the drive circuit of the trigger circuit based on the second signal, the IGCT device is controlled to shut down and the gate clamping circuit connected to the IGCT device is controlled to disconnect.

7. The IGCT overvoltage protection method according to claim 1, characterized in that, Generating a second control command to enable a second device for performing transient voltage protection includes: A second control command is generated to close the target bypass of the submodule, thereby isolating the submodule; A second device is provided on the target bypass.

8. An IGCT overvoltage protection device, characterized in that, include: The first module is used to acquire a first signal that feeds back the power supply status of the IGCT device in the feedback converter valve submodule and a second signal that feeds back the trigger status of the IGCT device. The second module is used to determine whether the input voltage change rate of the submodule exceeds a threshold when the converter valve is in operation, and to determine whether the drive power supply for driving the IGCT device is faulty according to the first signal, and to determine whether the trigger circuit for triggering the IGCT device is faulty according to the second signal. If the input voltage change rate of the submodule exceeds a threshold, and the drive power supply for driving the IGCT device is determined to be faulty according to the first signal, and the trigger circuit for triggering the IGCT device is determined to be faulty according to the second signal, then a first control command is generated to enable the first device for performing transient voltage protection. And when the converter valve is in the start-up phase, determine whether the input voltage change rate exceeds the second threshold and determine whether the drive power supply has output according to the first signal. If the input voltage change rate exceeds the second threshold or the drive power supply has no output according to the first signal, generate a second control command to enable the second device to perform transient voltage protection. Wherein, the first threshold is less than the second threshold, and the first device and the second device are located in the bypass of the IGCT device.

9. A controller, characterized in that, include: The memory is configured to store instructions; as well as The processor is configured to retrieve the instructions from the memory and, when executing the instructions, to implement the IGCT overvoltage protection method according to any one of claims 1 to 7.

10. A converter system, characterized in that, The device includes a converter submodule based on an IGCT device and a controller, the submodule being electrically connected to the controller, the controller being used to execute the IGCT overvoltage protection method according to any one of claims 1 to 7.

11. The converter system according to claim 10, characterized in that, The converter system further includes a first MOV device, a first device, a Zener diode, and a second device; the anode of the IGCT device is connected to the first end of the first MOV device, the first end of the first device, and the first end of the second device, respectively; the cathode of the Zener diode is connected to the second end of the first MOV device; and the cathode of the IGCT device is connected to the positive electrode of the Zener diode, the second end of the first device, and the second end of the second device, respectively.

12. The converter system according to claim 11, characterized in that, The first device is a transition device, which switches from a forward blocking state to a forward conducting state when its operating voltage rises to a predefined transition voltage.

13. The converter system according to claim 12, characterized in that, The transition device is a bidirectional transition thyristor or a second MOV device.

14. The converter system according to claim 11, characterized in that, The second device includes at least one of the following: a bypass switch, a bypass thyristor, an IGBT device, and a transition diode.

15. A machine-readable storage medium storing instructions thereon, characterized in that, When executed by a processor, this instruction causes the processor to be configured to perform the IGCT overvoltage protection method according to any one of claims 1 to 7.

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