Method and system for obtaining breakdown voltage of turn-on thyristor

Abstract

The present invention discloses a method and system for obtaining the breakdown voltage of a turn thyristor, the method comprising: performing multiple discharge pressure tests on the turn thyristor by changing the first capacity value of the capacitor module, obtaining multiple pairs of data consisting of the first capacity value and the corresponding clamping voltage; constructing a relationship function of the protection voltage-capacitor capacity of the turn thyristor based on the multiple pairs of data; wherein 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 capacity value of a preset capacitor is used as the second capacity value, input into the relationship function, and the target breakdown voltage when the preset capacitor presses the turn thyristor is calculated. The present invention can accurately calculate the breakdown voltage formed when a large capacitor presses the turn thyristor without damaging the turn thyristor.

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 the UHV flexible DC transmission project, the normal operation of the bypass switch is crucial, as it ensures the safety and reliability of the entire power system. In order to overcome the problem of the bypass switch refusing to operate due to its own reasons at critical moments, a high-reliability bypass technology is implemented by configuring a precise voltage turning thyristor at the AC port of the power module. This bypass technology effectively solves the problem of power system locking or tripping that may occur due to a single module failure of the flexible DC converter valve.

[0003] When a fault occurs in the power system, the voltage will deviate from the normal range. At this time, the turn-over thyristor in the bypass system can quickly make a hard turn when the voltage reaches the preset voltage value, forming a reliable short-circuit protection, relying on its precise voltage turn-over characteristics. This not only meets the bypass protection requirements in the event of a fault, but also meets the engineering requirements of long-term stable current flow.

[0004] However, to achieve this efficient bypass protection, the breakdown voltage of the turn-on thyristor needs to be accurately calibrated. Directly measuring the breakdown voltage of the turn-on thyristor will cause damage to the device. Therefore, how to accurately measure the breakdown voltage of the turn-on thyristor without damaging it has become a challenge that needs to be solved urgently. 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 the protection voltage and the capacitor capacity is constructed, so as to accurately calculate the breakdown voltage formed when a large capacitor applies pressure to the turning thyristor without damaging the turning thyristor.

[0006] A first aspect of the present invention provides a method for obtaining a breakdown voltage of a thyristor, comprising:

[0007] 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;

[0008] 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;

[0009] 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.

[0010] 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:

[0011] 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;

[0012] The polynomial function is used as a relationship function between protection voltage and capacitor capacity.

[0013] Optionally, the relationship function is specifically:

[0014] ;

[0015] in, To protect the voltage; is the capacitor capacity; , , and are polynomial coefficients.

[0016] Optionally, the step of changing the first capacity 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 capacity value and the corresponding clamping voltage includes:

[0017] Based on a specified power supply voltage, charging the capacitor module;

[0018] After charging is completed, capacitor units with different first capacitance values ​​are selected through a switch unit built into the capacitor module;

[0019] 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.

[0020] Optionally, the first capacitance value is less than 200 μF.

[0021] 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.

[0022] Optionally, the discharge pressure test is performed by a clamp voltage test circuit; wherein the clamp voltage test circuit comprises: a capacitor charging module, the capacitor module, a discharge switch and the turning thyristor;

[0023] The capacitor charging module is used to provide a specified power supply voltage for charging the capacitor module;

[0024] The capacitor module is used to select capacitor units with different first capacitance values ​​through a built-in switch unit;

[0025] The discharge switch is used to control the discharge operation of the selected capacitor unit to the transition thyristor.

[0026] Optionally, the clamp voltage test circuit further includes: an RC loop;

[0027] The RC circuit is used to control the rising voltage of the transition thyristor when the selected capacitor unit is discharged.

[0028] Optionally, the capacitor module comprises: N capacitor units and N switch units; wherein N≥1;

[0029] The capacitor units are connected in series with the corresponding switch units, and all the capacitor units are connected in parallel.

[0030] A second aspect of the present invention provides a system for obtaining a breakdown voltage of a thyristor, comprising:

[0031] 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;

[0032] 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;

[0033] 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.

[0034] Compared with the prior art, the embodiment of the present invention provides a method and system for obtaining the breakdown voltage of a turning thyristor, the method comprising: by changing the first capacity value of the capacitor module, performing multiple discharge pressure tests on the turning thyristor, obtaining multiple pairs of data consisting of the first capacity value and the corresponding clamping voltage; based on the multiple pairs of data, constructing a relationship function between the protection voltage of the turning thyristor and the capacitor capacity; wherein 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 capacity value of the preset capacitor is used as the second capacity value, input into the relationship function, and the target breakdown voltage when the preset capacitor presses the turning thyristor is calculated. The present invention can accurately calculate the breakdown voltage formed when a large capacitor presses the turning thyristor without damaging the turning thyristor. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of an embodiment of a method for obtaining the breakdown voltage of a thyristor provided by the present invention;

[0036] Figure 2 It is a structural schematic diagram of an embodiment of a voltage clamping test circuit based on a transition thyristor provided by the present invention;

[0037] 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;

[0038] Figure 4 It is a schematic diagram of an embodiment of a breakdown test circuit based on a transition thyristor provided by the present invention;

[0039] Figure 5 It is a structural schematic diagram of an embodiment of a system for obtaining a breakdown voltage of a thyristor provided by the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this technical field without creative work are within the scope of protection of the present invention.

[0041] 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.

[0042] The first aspect 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:

[0043] Step S1: by changing the first capacitance value of the capacitor module, performing multiple discharge pressure tests on the turning thyristor, and obtaining multiple pairs of data consisting of the first capacitance value and the corresponding clamping voltage; wherein the first capacitance value is a microfarad capacitance;

[0044] Step S2: constructing a relationship function between the protection voltage of the turn thyristor and the capacitor capacity based on a plurality of pairs of the data; wherein 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;

[0045] Step S3: inputting the capacitance value of a preset capacitor as the second capacitance value into the relationship function, and calculating the target breakdown voltage when the preset capacitor applies pressure to the turning thyristor; wherein the second capacitance value is in the millifarad level.

[0046] It should be noted that in actual engineering applications, large-capacity capacitors will directly break down the transition thyristor when discharging. However, when the inventors conducted a discharge pressure test on the transition thyristor with a small-capacity capacitor (i.e., the capacitor unit in the capacitor module), they found that within a certain voltage range, the transition thyristor would show obvious voltage clamping phenomenon and would not be damaged by the applied voltage breakdown. Furthermore, the inventors also found that in the discharge pressure test of small capacitors with different capacitance values ​​(first capacitance value), the clamping voltage value of the transition thyristor showed a certain regularity.

[0047] In addition, the inventors also tested the breakdown voltage of the thyristor caused by the discharge breakdown of the large-capacity capacitor, and based on multiple experiments, 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, a "mapping function of clamping voltage-first capacity value" of the small-capacity capacitor is constructed by a plurality of data pairs consisting of the first capacity value and the corresponding clamping voltage, and the mapping function can also be characterized as a "mapping function of breakdown voltage-second capacity value" of the large-capacity capacitor. The embodiment of the present invention collectively refers to the above-mentioned mapping functions as "relationship functions of protection voltage-capacitor capacity"; wherein the protection voltage includes: clamping voltage or breakdown voltage; the capacitor capacity includes: first capacity value or second capacity value.

[0048] In the specific implementation, firstly, by changing the first capacitance value of the capacitor module (i.e., replacing a small capacitance capacitor), a plurality of data pairs consisting of the first capacitance value and the corresponding clamping voltage are obtained; then, based on these data pairs, a relationship function between the protection voltage and the capacitance of the capacitor is constructed; finally, the capacitance value of the preset capacitor is input into the relationship function, and the breakdown voltage when the preset capacitor (i.e., the large capacitance capacitor) discharges and presses the turning thyristor is accurately calculated. Based on this, the embodiment of the present invention can accurately calculate the breakdown voltage formed when the large capacitor presses the turning thyristor without damaging the turning thyristor.

[0049] In an optional embodiment, constructing a relationship function between the protection voltage of the transition thyristor and the capacitor capacity based on the plurality of data pairs includes:

[0050] 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;

[0051] The polynomial function is used as a relationship function between protection voltage and capacitor capacity.

[0052] Furthermore, the relationship function is specifically:

[0053] ;

[0054] in, To protect the voltage; is the capacitor capacity; , , and are polynomial coefficients.

[0055] 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) fit the following polynomial to the corresponding capacitor capacity:

[0056] ;in, It 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).

[0057] In other words, “the relationship function between protection voltage and capacitor capacitance” = “the polynomial function between clamping voltage and first capacitance value” = “the mapping function between breakdown voltage and second capacitance value”.

[0058] 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, and tests the data pairs consisting of the first capacitance value of each small-capacity capacitor and the corresponding clamping voltage, thereby obtaining the relationship function between the protection voltage and the capacitor capacitance, and inferring the breakdown voltage of the large-capacity capacitor that breaks down the turning thyristor.

[0059] In an optional embodiment, the first capacitance value of the capacitor module is changed, and the discharge pressure test is performed on the turning thyristor for multiple times to obtain multiple pairs of data consisting of the first capacitance value and the corresponding clamping voltage, including:

[0060] Based on a specified power supply voltage, charging the capacitor module;

[0061] After charging is completed, capacitor units with different first capacitance values ​​are selected through a switch unit built into the capacitor module;

[0062] 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.

[0063] It should be noted that when the turning thyristor is subjected to multiple discharge pressure tests, the capacitor module is provided with the same specified power supply voltage for charging.

[0064] In an optional embodiment, the first capacitance value is less than 200 μF.

[0065] 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.

[0066] It should be noted that the inventors have found through multiple experimental tests that when the first capacitance value of the capacitor unit in the capacitor module is less than 200 μF, and its capacitance voltage is near 1.3 times the repetitive peak voltage of the turning thyristor, the voltage applied by the capacitor unit to the turning thyristor during the discharge process can effectively generate a clamping voltage without causing breakdown damage to the thyristor. In addition, the capacitance voltage of the capacitor unit is provided by a specified power supply voltage.

[0067] See also Figure 2 , is a structural schematic diagram of an embodiment of a voltage clamping test circuit based on a transition thyristor provided by the present invention.

[0068] 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;

[0069] The capacitor charging module 100 is used to provide a specified power supply voltage for charging the capacitor module 200;

[0070] The capacitor module 200 is used to select capacitor units with different first capacitance values ​​through a built-in switch unit;

[0071] The discharge switch 300 is used to control the discharge operation of the selected capacitor unit to the turning thyristor 400 .

[0072] It should be noted that at the beginning of the clamping test of the turning thyristor 400, the capacitor charging module 100 is first started to provide a specified power supply voltage to the capacitor module 200, so that the voltage of each capacitor unit in the capacitor module 200 can reach the voltage level required for the test. After the charging is completed, the capacitor module 200 flexibly selects capacitor units with different first capacitance values ​​for testing through the built-in switch unit. After the capacitor unit is selected, the discharge switch 300 (usually a high-speed electronic switch) is triggered to control the capacitor unit to discharge to the turning thyristor 400. During the discharge process, the capacitor unit applies a voltage to the turning thyristor 400, which causes the thyristor to generate a clamping voltage.

[0073] In an optional embodiment, the clamp voltage test circuit further includes: an RC loop 500;

[0074] The RC loop 500 is used to control the rising voltage of the transition thyristor 400 when the selected capacitor unit is discharged.

[0075] It should be noted that the RC loop 500 adjusts the voltage rise rate of the turning thyristor 400 by adjusting the settings of the resistor and the capacitor, thereby ensuring that the thyristor can withstand rapid voltage changes without being damaged, that is, avoiding electrical shocks to the thyristor caused by sudden voltage rise.

[0076] 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:

[0077] In the first embodiment, the capacitor module 200 includes: N capacitor units and 1 multi-way switch; wherein the multi-way switch includes but is not limited to a switch tube, a switch array, and a multiplexer.

[0078] In a second embodiment, the capacitor module 200 includes: N capacitor units and N switch units; wherein N≥1;

[0079] The capacitor units are connected in series with the corresponding switch units, and all the capacitor units are connected in parallel.

[0080] In order to further reflect the technical effect achieved by the method for obtaining the breakdown voltage of a turning thyristor provided by the present invention, the technical effect of the present invention is described below in conjunction with an application example of obtaining the breakdown voltage of a turning thyristor by the inventor during the research and development process.

[0081] 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 isolating switch), ④ is an RC circuit 500, and ⑤ is a turning thyristor 400.

[0082] The steps for the clamping test of the thyristor are as follows:

[0083] Step 1: Test the repetitive peak voltage V0 of the turning thyristor at junction temperature.

[0084] Step 2: Adjust the power supply voltage U1 to 1.3 times V0; open S1, disconnect S2, S3 and S4, and connect the C1 capacitor to the discharge circuit; start testing the turning thyristor at the junction temperature, trigger the fast isolating switch, discharge the C1 capacitor to put pressure on the turning thyristor, and test the clamping voltage value VB1 at both ends of the turning thyristor.

[0085] Step 3: Repeat step 2 and adjust the power supply voltage U1 to 1.3 times of V0; turn on 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 isolating switch, discharge capacitor C2, and test the clamping voltage value VB2 across the turning thyristor.

[0086] 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 in turn; similarly, test the clamping voltage value VB4 at both ends of the turning thyristor corresponding to the discharge of capacitor C4.

[0087] Step 5: Calculate the discharge breakdown voltage of the large-capacity capacitor through VB1, VB2, VB3, VB4 and the corresponding capacitor capacity. , as follows:

[0088] (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.

[0089] (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. .

[0090] Example of clamp pressure calculation experiment:

[0091] The measured voltage across the thyristor 2uF capacitor discharge corresponds to the clamping voltage VB1=4263V.

[0092] The measured voltage across the 10uF capacitor of the turning thyristor is VB2=4269V.

[0093] The measured voltage across the 50uF capacitor of the turning thyristor is VB3=4278V.

[0094] The measured clamping voltage value VB4=4282V across the turning thyristor corresponding to the discharge of the 100uF capacitor of the turning thyristor.

[0095] 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:

[0096] .

[0097] The second capacitance value of the preset capacitor is 24mF=24000uF, which is calculated by the above final relationship function. .

[0098] 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.

[0099] 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 capacity value is 24mF=24000uF), ⑧ is a resistor (the resistance value is less than 0.1Ω), and ⑨ is a turning thyristor.

[0100] 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.

[0101] Measured breakdown voltage .

[0102] The actual breakdown voltage is compared with the test inferred voltage as follows:

[0103] Error accuracy = ;

[0104] Error accuracy = ;

[0105] Error precision = 0.09.

[0106] See also Figure 5 , is a structural schematic diagram of an embodiment of a system for acquiring a breakdown voltage of a transition thyristor provided by the present invention.

[0107] A second aspect of the present invention provides a system for obtaining a breakdown voltage of a turn-on thyristor, which is used to implement the method for obtaining a breakdown voltage of a turn-on thyristor described in any one of the embodiments of the first aspect. The system includes:

[0108] The test data acquisition module 11 is 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;

[0109] A relationship function construction module 12 is used to construct a relationship function of the protection voltage of the turning thyristor-capacitor capacity based on multiple pairs of the 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; 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;

[0110] 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 belongs to the millifarad level capacitance.

[0111] It should be noted that the breakdown voltage acquisition system of the turning thyristor provided in the second aspect embodiment of the present invention can realize all the processes of the breakdown voltage acquisition method of the turning thyristor described in the above-mentioned first aspect embodiment. 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 of the turning thyristor described in the above-mentioned first aspect embodiment, and will not be repeated here.

[0112] 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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