Method and system for acquiring breakdown voltage of turning thyristor

Abstract

The invention discloses a breakdown voltage acquisition method and system for a turning thyristor, and the method comprises the steps: carrying out the multiple discharge voltage application tests of the turning thyristor through changing the first capacity value of a capacitor module, and obtaining a data pair composed of a plurality of pairs of first capacity values and corresponding clamping voltages; based on the multiple data pairs, constructing a protection voltage-capacitor capacity relation function of the turning thyristor; wherein the relation function is used for representing a mapping relation between the clamping voltage and the first capacity value, or a mapping relation between the breakdown voltage and the second capacity value; and taking the capacity value of the preset capacitor as a second capacity value, inputting the second capacity value into the relation function, and calculating to obtain a target breakdown voltage when the preset capacitor applies pressure to the turning thyristor. According to the method, the breakdown voltage formed when the large capacitor applies pressure to the turning thyristor can be accurately calculated on the premise that the turning thyristor is not damaged.

Description

Technical Field

[0001] The present invention relates to the technical field of power semiconductor devices, and in particular to a method and system for obtaining the breakdown voltage of a thyristor. Background Art

[0002] In UHVDC flexible transmission projects, the proper operation of bypass switches is crucial, ensuring the safety and reliability of the entire power system. To overcome the problem of bypass switches failing to operate at critical moments due to faulty circuitry, a highly reliable bypass technology is implemented by configuring precise voltage-controlled thyristors (SCRs) at the AC ports of power modules. This bypass technology effectively addresses the potential for power system lockout or tripping caused by a single module failure in the flexible DC converter valve.

[0003] When a power system fault occurs, the voltage deviates from the normal range. At this point, the bypass system's turnaround thyristors, leveraging their precise voltage turnaround characteristics, can quickly perform a hard turnaround when the voltage reaches the preset value, providing reliable short-circuit protection. This not only meets the bypass protection requirements in fault situations, but also meets the engineering requirements for long-term stable current flow.

[0004] However, achieving this efficient bypass protection requires precise calibration of the breakdown voltage of the thyristor. Directly measuring the breakdown voltage of the thyristor can damage the device. Therefore, accurately measuring the breakdown voltage of the thyristor without damaging it has become a pressing challenge. Summary of the Invention

[0005] The purpose of the embodiments of the present invention is to provide a method and system for obtaining the breakdown voltage of a turning thyristor. By measuring the clamping voltage of a small capacitor, a relationship function between protection voltage and capacitor capacitance is constructed, so that the breakdown voltage formed when a large capacitor applies pressure to the turning thyristor can be accurately calculated without damaging the turning thyristor.

[0006] A first embodiment of the present invention provides a method for obtaining a breakdown voltage of a thyristor, comprising: By changing the first capacitance value of the capacitor module, multiple discharge pressure tests are performed on the turning thyristor to obtain multiple data pairs consisting of first capacitance values ​​and corresponding clamping voltages; wherein the first capacitance value is in the microfarad range; Based on the plurality of data pairs, a relationship function between the protection voltage of the thyristor and the capacitor capacity is constructed; wherein the protection voltage includes: a clamping voltage or a breakdown voltage; the capacitor capacity includes: a first capacity value and a second capacity value; the relationship function is used to represent a mapping relationship between the clamping voltage and the first capacity value, or a mapping relationship between the breakdown voltage and the second capacity value; The capacitance value of a preset capacitor is used as the second capacitance value and input into the relationship function to calculate the target breakdown voltage when the preset capacitor applies pressure to the turning thyristor; wherein the second capacitance value is a millifarad capacitance.

[0007] Optionally, constructing a relationship function between the protection voltage of the transition thyristor and the capacitor capacity based on the plurality of data pairs includes: Inputting a plurality of pairs of the data into a polynomial fitting model to solve the polynomial coefficients, and obtaining a polynomial function of the clamping voltage-first capacity value of the transition thyristor; The polynomial function is used as a relationship function between protection voltage and capacitor capacity.

[0008] Optionally, the relationship function is specifically: ; in, To protect the voltage; is the capacitor capacity; 、 、 and are polynomial coefficients.

[0009] Optionally, the step of performing multiple discharge pressure tests on the turning thyristor by changing the first capacitance value of the capacitor module to obtain multiple data pairs consisting of the first capacitance value and the corresponding clamping voltage includes: charging the capacitor module based on a specified power supply voltage; After charging is completed, capacitor units with different first capacitance values ​​are selected through a built-in switch unit in the capacitor module; The turning thyristor is discharged and pressurized based on the selected capacitor unit to obtain the clamping voltage corresponding to the first capacitance value and form the data pair.

[0010] Optionally, the first capacitance value is less than 200 μF.

[0011] Optionally, the specified power supply voltage is set within a preset voltage range centered around 1.3 times the repetitive peak voltage of the transition thyristor.

[0012] Optionally, the discharge pressure test is performed by a voltage clamp test circuit; wherein the voltage clamp test circuit includes: a capacitor charging module, the capacitor module, a discharge switch and the turning thyristor; The capacitor charging module is used to provide a specified power supply voltage to the capacitor module for charging; The capacitor module is configured to select capacitor units having different first capacitance values ​​through a built-in switch unit; The discharge switch is used to control the discharge operation of the selected capacitor unit on the turning thyristor.

[0013] Optionally, the clamp voltage test circuit further includes: an RC loop; The RC circuit is used to control the rising voltage of the transition thyristor when the selected capacitor unit is discharged.

[0014] Optionally, the capacitor module includes: N capacitor units and N switch units; wherein N≥1; The capacitor units are connected in series with the corresponding switch units, and all the capacitor units are connected in parallel.

[0015] A second embodiment of the present invention provides a system for obtaining a breakdown voltage of a thyristor, comprising: a test data acquisition module, configured to perform multiple discharge and pressure tests on the turning thyristor by varying the first capacitance value of the capacitor module, and acquire multiple data pairs consisting of the first capacitance value and the corresponding clamping voltage; wherein the first capacitance value is in the microfarad range; a relationship function construction module, configured to construct a relationship function between the protection voltage of the thyristor and the capacitor capacity based on a plurality of pairs of the data; wherein the protection voltage includes: a clamping voltage or a breakdown voltage; the capacitor capacity includes: a first capacity value and a second capacity value; and the relationship function is configured to represent a mapping relationship between the clamping voltage and the first capacity value, or a mapping relationship between the breakdown voltage and the second capacity value; A breakdown voltage calculation module is used to input the capacitance value of a preset capacitor as the second capacitance value into the relationship function to calculate the target breakdown voltage when the preset capacitor applies pressure to the turning thyristor; wherein the second capacitance value is a millifarad capacitance.

[0016] Compared with the prior art, the embodiments of the present invention provide a method and system for obtaining the breakdown voltage of a turn thyristor. The method includes: performing multiple discharge pressure tests on the turn thyristor by changing the first capacitance value of the capacitor module to obtain multiple pairs of data consisting of the first capacitance value and the corresponding clamping voltage; based on the multiple pairs of data, constructing a relationship function between the protection voltage of the turn thyristor and the capacitance of the capacitor; wherein the relationship function is used to characterize the mapping relationship between the clamping voltage and the first capacitance value, or the mapping relationship between the breakdown voltage and the second capacitance value; the capacitance value of a preset capacitor is used as the second capacitance value and input into the relationship function to calculate the target breakdown voltage when the preset capacitor applies pressure to the turn thyristor. The present invention can accurately calculate the breakdown voltage formed when a large capacitor applies pressure to the turn thyristor without damaging the turn thyristor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of an embodiment of a method for obtaining the breakdown voltage of a transition thyristor provided by the present invention; Figure 2 1 is a schematic structural diagram of an embodiment of a voltage clamping test circuit based on a transition thyristor provided by the present invention; Figure 3 1 is a schematic diagram of another embodiment of a voltage clamping test circuit based on a transition thyristor provided by the present invention; Figure 4 1 is a schematic diagram of an embodiment of a breakdown test circuit based on a thyristor provided by the present invention; Figure 5 The figure is a structural diagram of an embodiment of a system for obtaining the breakdown voltage of a thyristor provided by the present invention. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this technical field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0019] See also Figure 1 , is a flow chart of an embodiment of a method for obtaining the breakdown voltage of a transition thyristor provided by the present invention.

[0020] The first embodiment of the present invention provides a method for obtaining the breakdown voltage of a thyristor, including steps S1 to S3, which are specifically as follows: Step S1: performing multiple discharge and pressure tests on the thyristor by varying the first capacitance value of the capacitor module to obtain multiple data pairs consisting of first capacitance values ​​and corresponding clamping voltages; wherein the first capacitance value is in the microfarad range; Step S2: constructing a relationship function between the protection voltage of the thyristor and the capacitor capacity based on the plurality of data pairs; wherein the relationship function is used to represent a mapping relationship between the clamping voltage and the first capacity value, or a mapping relationship between the breakdown voltage and the second capacity value; Step S3: inputting the capacitance value of a preset capacitor as the second capacitance value into the relationship function to calculate the target breakdown voltage when the preset capacitor applies pressure to the turning thyristor; wherein the second capacitance value is in the millifarad range.

[0021] It should be noted that in actual engineering applications, large-capacity capacitors will directly break down the transition thyristor during discharge. However, when the inventors conducted discharge pressure tests on the transition thyristor using small-capacity capacitors (i.e., capacitor units in a capacitor module), they found that within a certain voltage range, the transition thyristor exhibited significant voltage clamping and was not damaged by the applied voltage. Furthermore, the inventors also found that in discharge pressure tests on small capacitors with different capacitance values ​​(first capacitance value), the clamping voltage values ​​of the transition thyristor showed a certain regularity.

[0022] In addition, the inventors also tested the breakdown voltage of the thyristor caused by the discharge breakdown of the large-capacity capacitor. Based on multiple experiments, they found that there is a correlation between the clamping voltage formed by the discharge of the small-capacity capacitor (i.e., the capacitor unit in the capacitor module) and the breakdown voltage caused by the discharge of the large-capacity capacitor (i.e., the preset capacitor). Specifically, by using multiple pairs of data consisting of first capacitance values ​​and corresponding clamping voltages, a "clamping voltage-first capacitance value mapping function" is constructed for the small-capacity capacitor. This mapping function can also be characterized as a "breakdown voltage-second capacitance value mapping function" for the large-capacity capacitor. In the embodiments of the present invention, the above mapping functions are collectively referred to as "protection voltage-capacitor capacitance relationship functions"; wherein the protection voltage includes: clamping voltage or breakdown voltage; the capacitor capacitance includes: first capacitance value or second capacitance value.

[0023] In a specific implementation, the first capacitance value of the capacitor module is changed (i.e., replacing a small-capacity capacitor) to obtain multiple data pairs consisting of the first capacitance value and the corresponding clamping voltage. Next, a relationship function between the protection voltage and the capacitor capacitance is constructed based on these data pairs. Finally, the capacitance value of the preset capacitor is input into the relationship function to accurately calculate the breakdown voltage of the preset capacitor (i.e., the large-capacity capacitor) when it discharges and applies pressure to the turning thyristor. Based on this, the embodiment of the present invention can accurately calculate the breakdown voltage formed when a large capacitor applies pressure to the turning thyristor without damaging the turning thyristor.

[0024] In an optional embodiment, constructing a relationship function between the protection voltage of the thyristor and the capacitor capacity based on the plurality of data pairs includes: Inputting a plurality of pairs of the data into a polynomial fitting model to solve the polynomial coefficients, and obtaining a polynomial function of the clamping voltage-first capacity value of the transition thyristor; The polynomial function is used as a relationship function between protection voltage and capacitor capacity.

[0025] Furthermore, the relationship function is specifically: ; in, To protect the voltage; is the capacitor capacity; 、 、 and are polynomial coefficients.

[0026] It should be noted that the protection voltage includes: clamping voltage or breakdown voltage; the capacitor capacity includes: first capacity value or second capacity value. The clamping voltage formed by the discharge of the small-capacity capacitor (i.e., the capacitor unit in the capacitor module) and the breakdown voltage caused by the discharge of the large-capacity capacitor (i.e., the preset capacitor) are fitted with the following polynomials to the corresponding capacitor capacities: ;in, Indicates the clamping voltage formed by the discharge of a small-capacity capacitor (i.e., the capacitor unit in the capacitor module), or the breakdown voltage caused by the discharge of a large-capacity capacitor (i.e., the preset capacitor).

[0027] In other words, the “relationship function of protection voltage-capacitor capacitance” = “polynomial function of clamping voltage-first capacitance value” = “mapping function of breakdown voltage-second capacitance value”.

[0028] Therefore, the embodiment of the present invention uses the characteristic that a small-capacity capacitor can generate a clamping voltage within a certain voltage range without causing the turning thyristor to break down when applying a voltage to the turning thyristor, tests the data pairs consisting of the first capacitance value of each small-capacity capacitor and the corresponding clamping voltage, and then obtains the relationship function between the protection voltage and the capacitor capacitance, and infers the breakdown voltage of the large-capacity capacitor that breaks down the turning thyristor.

[0029] In an optional embodiment, the step of performing multiple discharge pressure tests on the turning thyristor by changing the first capacitance value of the capacitor module to obtain multiple data pairs consisting of the first capacitance value and the corresponding clamping voltage includes: charging the capacitor module based on a specified power supply voltage; After charging is completed, capacitor units with different first capacitance values ​​are selected through a built-in switch unit in the capacitor module; The turning thyristor is discharged and pressurized based on the selected capacitor unit to obtain the clamping voltage corresponding to the first capacitance value and form the data pair.

[0030] It should be noted that when multiple discharge and pressure tests are performed on the turning thyristor, the same specified power supply voltage is provided to the capacitor module for charging.

[0031] In an optional embodiment, the first capacitance value is less than 200 μF.

[0032] Furthermore, the specified power supply voltage is set within a preset voltage range centered around 1.3 times the repetitive peak voltage of the transition thyristor.

[0033] It should be noted that after multiple experimental tests, the inventors have found that when the first capacitance value of the capacitor unit in the capacitor module is less than 200 μF and its capacitor voltage is approximately 1.3 times the repetitive peak voltage of the turn thyristor, the voltage applied by the capacitor unit to the turn thyristor during discharge can effectively generate a clamping voltage without causing breakdown damage to the thyristor. Furthermore, the capacitor voltage of the capacitor unit is provided by a specified power supply voltage.

[0034] See also Figure 2 , is a structural diagram of an embodiment of a voltage clamping test circuit based on a transition thyristor provided by the present invention.

[0035] In an optional embodiment, the discharge pressure test is performed by a voltage clamp test circuit; wherein the voltage clamp test circuit includes: a capacitor charging module 100, the capacitor module 200, a discharge switch 300 and the turning thyristor 400; The capacitor charging module 100 is used to provide a specified power supply voltage to the capacitor module 200 for charging; The capacitor module 200 is configured to select capacitor units having different first capacitance values ​​through a built-in switch unit; The discharge switch 300 is used to control the discharge operation of the selected capacitor unit on the turning thyristor 400.

[0036] It should be noted that at the start of the voltage clamp test on the turning thyristor 400, the capacitor charging module 100 is first activated to provide a specified power supply voltage to the capacitor module 200, ensuring that the voltage of each capacitor unit in the capacitor module 200 reaches the required test voltage level. After charging is completed, the capacitor module 200 uses a built-in switch unit to flexibly select capacitor units with different first capacitance values ​​for testing. After selecting a capacitor unit, the discharge switch 300 (typically a high-speed electronic switch) is triggered, controlling the capacitor unit to discharge into the turning thyristor 400. During the discharge process, the capacitor unit applies a voltage to the turning thyristor 400, causing the thyristor to generate a clamping voltage.

[0037] In an optional embodiment, the voltage clamp test circuit further includes: an RC loop 500; The RC circuit 500 is used to control the rising voltage of the turning thyristor 400 when the selected capacitor unit is discharged.

[0038] It should be noted that the RC circuit 500 adjusts the voltage rise rate of the turning thyristor 400 by adjusting the settings of the resistor and capacitor, thereby ensuring that the thyristor can withstand rapid voltage changes without being damaged, that is, avoiding the electrical shock that may be caused to the thyristor by a sudden voltage rise.

[0039] In order for the capacitor module 200 to be able to select capacitor units with different first capacitance values ​​through the built-in switch unit: In a first embodiment, the capacitor module 200 includes: N capacitor units and a multi-way switch; wherein the multi-way switch includes but is not limited to a switch tube, a switch array, and a multiplexer.

[0040] In a second embodiment, the capacitor module 200 includes: N capacitor units and N switch units; wherein N≥1; The capacitor units are connected in series with the corresponding switch units, and all the capacitor units are connected in parallel.

[0041] In order to further demonstrate the technical effects achieved by the method for obtaining the breakdown voltage of a transition thyristor provided by the present invention, the technical effects of the present invention are described below in conjunction with an application example of obtaining the breakdown voltage of a transition thyristor during the research and development process of the inventor.

[0042] See also Figure 3 , is a schematic diagram of another embodiment of a voltage clamping test circuit based on a transition thyristor provided by the present invention. Figure 3 ① is a capacitor charging module 100, ② is a capacitor module 200 (i.e., a parallel capacitor switching component), ③ is a discharge switch 300 (i.e., a high-speed electronic switch / fast isolation switch), ④ is an RC circuit 500, and ⑤ is a turning thyristor 400.

[0043] The steps for the clamping test of the thyristor are as follows: Step 1: Test the repetitive peak voltage V0 of the turn-on thyristor at junction temperature.

[0044] Step 2: Adjust the power supply voltage U1 to 1.3 times V0; open S1, disconnect S2, S3 and S4, and connect the capacitor C1 to the discharge circuit; start testing the turning thyristor at junction temperature, trigger the fast isolation switch, discharge the capacitor C1 to apply pressure to the turning thyristor, and test the clamping voltage value VB1 across the turning thyristor.

[0045] Step 3: Repeat step 2 and adjust the power supply voltage U1 to 1.3 times V0; open S2, disconnect S1, S3, and S4, and connect capacitor C2 to the discharge circuit; start testing the turning thyristor at junction temperature, trigger the fast isolation switch, discharge capacitor C2, and test the clamping voltage value VB2 across the turning thyristor.

[0046] Step 4: Repeat step 3 to test the clamping voltage value VB3 at both ends of the turning thyristor corresponding to the discharge of capacitor C3; similarly, test the clamping voltage value VB4 at both ends of the turning thyristor corresponding to the discharge of capacitor C4.

[0047] Step 5: Calculate the discharge breakdown voltage of the large-capacity capacitor through VB1, VB2, VB3, VB4 and the corresponding capacitor capacity. , as follows: (1) Substitute (C1, VB1), (C2, VB2), (C3, VB3) and (C4, VB4) into the polynomial fitting model Solve for the polynomial coefficients 、 、 and , the fitting polynomial is obtained and used as the relationship function between protection voltage and capacitor capacity.

[0048] (2) Substitute the second capacitance value of the preset capacitor (large capacitance capacitor) into the final relationship function to obtain the target breakdown voltage when the preset capacitor applies pressure to the turning thyristor. .

[0049] Example of clamp pressure calculation experiment: The clamping voltage value VB1 of the turning thyristor corresponding to the discharge of the 2uF capacitor of the turning thyristor is 4263V. The clamping voltage value VB2 of the turning thyristor corresponding to the discharge of the 10uF capacitor of the turning thyristor is 4269V. The clamping voltage value VB3 of the turning thyristor corresponding to the discharge of the 50uF capacitor of the turning thyristor is 4278V. The clamping voltage value VB4=4282V at both ends of the turning thyristor corresponding to the discharge of the 100uF capacitor of the turning thyristor is measured.

[0050] Solve the parameter values ​​in the relationship function between protection voltage and capacitor capacity through VB1, VB2, VB3, and VB4 、 、 and , that is, the final relationship function is: .

[0051] The second capacitance value of the preset capacitor is 24mF=24000uF, which is calculated by the above final relationship function. .

[0052] In order to verify the accuracy of the results of the clamping voltage estimation experiment example, the inventors also provide a breakdown experiment example of a transition thyristor.

[0053] See also Figure 4 , is a schematic diagram of an embodiment of a breakdown test circuit based on a transition thyristor provided by the present invention. Figure 4 ⑥ is a capacitor charging module, ⑦ is a preset capacitor (a large-capacity capacitor, that is, the second capacitance value is 24mF=24000uF), ⑧ is a resistor (resistance is less than 0.1Ω), and ⑨ is a turning thyristor.

[0054] During the breakdown test of the turning thyristor, the capacitor charging module is first started to charge the preset capacitor and the voltage is continuously increased until the turning thyristor is broken down.

[0055] Measured breakdown voltage .

[0056] The actual breakdown voltage is compared with the test inferred voltage as follows: Error precision = ; Error precision = ; Error precision = 0.09.

[0057] See also Figure 5 , is a structural diagram of an embodiment of a system for obtaining the breakdown voltage of a transition thyristor provided by the present invention.

[0058] A second aspect of the present invention provides a system for obtaining a breakdown voltage of a turn-on thyristor, for implementing the method for obtaining a breakdown voltage of a turn-on thyristor described in any one of the first aspects of the present invention. The system includes: The test data acquisition module 11 is configured to perform multiple discharge and pressure tests on the thyristor by varying the first capacitance value of the capacitor module, thereby acquiring multiple data pairs consisting of first capacitance values ​​and corresponding clamping voltages; wherein the first capacitance value is in the microfarad range; A relationship function construction module 12 is configured to construct a relationship function between the protection voltage of the thyristor and the capacitor capacity based on the plurality of data pairs; wherein the protection voltage includes: a clamping voltage or a breakdown voltage; the capacitor capacity includes: a first capacity value and a second capacity value; and the relationship function is configured to represent a mapping relationship between the clamping voltage and the first capacity value, or a mapping relationship between the breakdown voltage and the second capacity value. The breakdown voltage calculation module 13 is used to input the capacitance value of the preset capacitor as the second capacitance value into the relationship function to calculate the target breakdown voltage when the preset capacitor applies pressure to the turning thyristor; wherein the second capacitance value is millifarad capacitance.

[0059] It should be noted that the breakdown voltage acquisition system for the turning thyristor provided in the embodiment of the second aspect of the present invention can realize all the processes of the breakdown voltage acquisition method for the turning thyristor described in the embodiment of the first aspect above. The functions of each module in the system and the technical effects achieved are respectively the same as the functions and technical effects achieved by the breakdown voltage acquisition method for the turning thyristor described in the embodiment of the first aspect above, and will not be repeated here.

[0060] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for obtaining the breakdown voltage of a thyristor, characterized in that: include: By changing the first capacitance value of the capacitor module, the turning thyristor is subjected to multiple discharge pressure tests to obtain multiple pairs of data consisting of first capacitance values ​​and corresponding clamping voltages; wherein the first capacitance value is a microfarad capacitance; Based on the plurality of pairs of data, a relationship function between the protection voltage of the turn thyristor and the capacitor capacity is constructed; wherein the protection voltage includes: a clamping voltage or a breakdown voltage; the capacitor capacity includes: a first capacity value and a second capacity value; the relationship function is used to characterize a mapping relationship between the clamping voltage and the first capacity value, or a mapping relationship between the breakdown voltage and the second capacity value; The capacitance value of a preset capacitor is used as the second capacitance value and input into the relationship function to calculate the target breakdown voltage when the preset capacitor applies pressure to the turning thyristor; wherein the second capacitance value belongs to the millifarad level capacitance.

2. The method for obtaining the breakdown voltage of a thyristor according to claim 1, characterized in that: The step of constructing a relationship function between the protection voltage of the transition thyristor and the capacitor capacity based on the plurality of data pairs includes: Inputting a plurality of pairs of the data into a polynomial fitting model to solve the polynomial coefficients, and obtaining a polynomial function of the clamping voltage-first capacity value of the transition thyristor; The polynomial function is used as a relationship function between protection voltage and capacitor capacity.

3. The method for obtaining the breakdown voltage of a thyristor according to claim 1, characterized in that: The relationship function is specifically: ； in, To protect the voltage; is the capacitor capacity; , , and are polynomial coefficients.

4. The method for obtaining the breakdown voltage of a thyristor according to claim 1, characterized in that: The method of changing the first capacitance value of the capacitor module and performing multiple discharge pressure tests on the turning thyristor to obtain multiple pairs of data consisting of the first capacitance value and the corresponding clamping voltage includes: Based on a specified power supply voltage, charging the capacitor module; After charging is completed, capacitor units with different first capacitance values ​​are selected through a switch unit built into the capacitor module; Based on the selected capacitor unit, the turning thyristor is discharged and pressurized to obtain the clamping voltage corresponding to the first capacitance value and form the data pair.

5. The method for obtaining the breakdown voltage of a thyristor according to claim 1, characterized in that: The first capacitance value is less than 200 μF.

6. The method for obtaining the breakdown voltage of a thyristor according to claim 4, characterized in that: The specified power supply voltage is set within a preset voltage range centered around 1.3 times the repetitive peak voltage of the transition thyristor.

7. The method for obtaining the breakdown voltage of a thyristor according to claim 1, characterized in that: The discharge pressure test is performed by a clamping voltage test circuit; wherein the clamping voltage test circuit comprises: a capacitor charging module, the capacitor module, a discharge switch and the turning thyristor; The capacitor charging module is used to provide a specified power supply voltage for charging the capacitor module; The capacitor module is used to select capacitor units with different first capacitance values ​​through a built-in switch unit; The discharge switch is used to control the discharge operation of the selected capacitor unit to the transition thyristor.

8. The method for obtaining the breakdown voltage of a thyristor according to claim 7, characterized in that: The clamp voltage test circuit also includes: an RC loop; The RC circuit is used to control the rising voltage of the transition thyristor when the selected capacitor unit is discharged.

9. The method for obtaining the breakdown voltage of a thyristor according to claim 7, characterized in that: The capacitor module comprises: N capacitor units and N switch units; wherein N≥1; The capacitor units are connected in series with the corresponding switch units, and all the capacitor units are connected in parallel.

10. A system for obtaining a breakdown voltage of a thyristor, characterized in that: include: A test data acquisition module, used to perform multiple discharge pressure tests on the turning thyristor by changing the first capacity value of the capacitor module, and obtain multiple pairs of data consisting of the first capacity value and the corresponding clamping voltage; wherein the first capacity value belongs to the microfarad level capacity; A relationship function construction module, used to construct a relationship function of the protection voltage of the turn thyristor-capacitor capacity based on multiple pairs of the data; wherein the protection voltage includes: a clamping voltage or a breakdown voltage; the capacitor capacity includes: a first capacity value and a second capacity value; the relationship function is used to characterize the mapping relationship between the clamping voltage and the first capacity value, or the mapping relationship between the breakdown voltage and the second capacity value; The breakdown voltage calculation module is used to input the capacitance value of a preset capacitor as the second capacitance value into the relationship function to calculate the target breakdown voltage when the preset capacitor applies pressure to the turning thyristor; wherein the second capacitance value belongs to the millifarad level capacitance.

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