A method, apparatus and system for voltage overshoot protection of a double pulse test

Abstract

The application provides a double-pulse test voltage overshoot protection method, device and system, relates to the technical field of module testing, and is characterized in that the method comprises the following steps: determining a test working condition of double-pulse automatic testing, testing a plurality of preset working condition points under the test working condition, collecting load current, load voltage and turn-off speed of each test, wherein the load voltage under the test of any working condition point does not exceed a threshold value; determining a change curve of the turn-off speed with the load current under the test working condition according to the test of the preset working condition points and performing curve fitting, and further calculating the stray inductance under each test to fit; obtaining real-time load current corresponding to a target working condition point, and determining a target turn-off speed; wherein the target working condition point is a working condition point after the plurality of preset working condition points; determining a target load voltage; when the target load voltage exceeds the threshold value, stopping the test of the target working condition point, and solving the problem that voltage overshoot may occur in the existing double-pulse test process and there is a great safety hazard.

Description

Technical Field

[0001] This invention relates to the field of module testing technology, and in particular to a voltage overshoot protection method, device and system for dual-pulse automatic testing. Background Technology

[0002] Double-pulse testing is a widely used method for evaluating the characteristics of power devices such as Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) and Insulated-Gate Bipolar Transistors (IGBTs). This test can assess the suitability of drive resistor values, the need for snubber circuits, and measure the performance of the switching transistor in actual circuits, including reverse recovery, turn-off voltage spikes, and turn-on / off times. However, during automated double-pulse testing, voltage overshoot may occur during turn-off, exceeding the power device's withstand voltage and potentially damaging the device, posing a significant safety hazard during the testing process. Summary of the Invention

[0003] In order to overcome the above-mentioned technical defects, the present invention aims to provide a voltage overshoot protection method, device and system for double pulse testing, which aims to solve the problem that voltage overshoot occurs in the existing double pulse testing process, posing a significant safety hazard.

[0004] This invention discloses a voltage overshoot protection method for dual-pulse testing, comprising:

[0005] A test condition for the double-pulse test is determined, wherein the test condition involves adjusting the load current under a certain driving resistor and a certain bus voltage.

[0006] Under the test conditions, multiple preset operating points were tested, and the load current, load voltage and turn-off speed were collected for each test. Under any operating point, the load voltage did not exceed the threshold.

[0007] Based on the test at the preset operating points, the curve of the turn-off speed versus the load current under the test conditions is determined and the curve is fitted. The stray inductance under each test is also calculated to fit the target stray inductance.

[0008] Obtain the real-time load current corresponding to the target operating point, and determine the target turn-off speed based on the curve of the turn-off speed versus the load current; wherein, the target operating point is an operating point after multiple preset operating points.

[0009] The target load voltage is determined based on the bus voltage, the target turn-off speed, and the target stray inductance.

[0010] When the target load voltage exceeds the threshold, the test of the target operating point is stopped.

[0011] Preferably, an objective function is established to determine the relationship between bus voltage, load voltage, turn-off speed, and stray inductance, in order to calculate the stray inductance under each test or to determine the target load voltage.

[0012] Preferably, the objective function is to obtain the load voltage by summing the product of the turn-off speed and stray inductance with the bus voltage.

[0013] Preferably, when the target load voltage does not exceed the threshold, the target operating point test is performed to obtain the real-time load voltage and real-time shutdown speed corresponding to the target load current.

[0014] Based on the real-time shutdown speed, the curve of the shutdown speed versus load current is fitted.

[0015] The real-time stray inductance is calculated based on the real-time load voltage and real-time turn-off speed, and the target stray inductance is fitted and adjusted.

[0016] Preferably, the curve of the turn-off speed versus load current is fitted based on the load current, bus voltage, and drive resistance.

[0017] Preferably, the driving resistor and / or the bus voltage are adjusted to perform tests under different test conditions.

[0018] Preferably, the stray inductance is calculated based on tests at multiple operating points under different test conditions, and the target stray inductance is fitted and adjusted.

[0019] The present invention also provides a voltage overshoot protection device for dual-pulse testing, comprising:

[0020] The data acquisition module is used to determine a test condition for the dual-pulse test, wherein the test condition is to adjust the load current for testing under a certain driving resistor and a certain bus voltage; under the test condition, multiple preset test points are performed, and the load current, load voltage and turn-off speed are collected for each test, wherein the load voltage does not exceed the threshold under any test point.

[0021] The calculation module is used to determine the curve of the turn-off speed versus load current under the test conditions based on the test at the preset operating points and to perform curve fitting. It also calculates the stray inductance under each test to fit and obtain the target stray inductance.

[0022] The processing module is used to acquire the real-time load current corresponding to the target operating point, and determine the target turn-off speed according to the curve of the turn-off speed changing with the load current; wherein, the target operating point is the operating point after multiple preset operating points; the target load voltage is determined according to the bus voltage, the target turn-off speed and the target stray inductance; when the target load voltage exceeds the threshold, the test of the target operating point is stopped.

[0023] The present invention also provides a dual-pulse testing system, which applies the voltage overshoot protection device of the aforementioned dual-pulse automatic testing to automatically perform dual-pulse testing.

[0024] Compared with existing technologies, the above technical solution has the following advantages:

[0025] The voltage overshoot protection method, device, and system for dual-pulse testing provided in this application, by configuring the test condition sequence of dual-pulse testing, calculating the fitting turn-off speed and module stray inductance online, can predict online whether there will be voltage overshoot at the next operating point based on the test results of historical operating points, thereby providing online safety protection for automated dual-pulse testing. It can also be calibrated based on the feedback parameters of the actual test, providing accurate safety warnings and solving the problem that voltage overshoot may occur in the existing dual-pulse testing process, which poses a safety hazard. Attached Figure Description

[0026] Figure 1 This is a flowchart of a first embodiment of the voltage overshoot protection method, device and system for dual-pulse testing according to the present invention;

[0027] Figure 2 This is a graph showing the change in turn-off speed with load current in Embodiment 1 of the voltage overshoot protection method, device and system for dual-pulse testing according to the present invention.

[0028] Figure 3 This is a stray inductance fitting curve diagram in Embodiment 1 of the voltage overshoot protection method, device and system for dual-pulse testing described in this invention;

[0029] Figure 4 This is a schematic diagram of a module in Embodiment 2 of the voltage overshoot protection method, device and system for dual-pulse testing according to the present invention.

[0030] Figure label:

[0031] 6- Voltage overshoot protection device for double pulse test; 61- Data acquisition module; 62- Calculation module; 63- Processing module. Detailed Implementation

[0032] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0033] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0034] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0035] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0036] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0038] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0039] Example 1: This example discloses a voltage overshoot protection method for dual-pulse testing, used to detect voltage overshoot during the turn-off process in dual-pulse testing to prevent damage to the module chip due to exceeding its withstand voltage value. Figure 1 As shown, it includes:

[0040] S100: Determine a test condition for the double pulse test, wherein the test condition is to adjust the load current for testing under a certain driving resistor and a certain bus voltage;

[0041] As an explanation, a large voltage is generated when the module performs a shutdown operation during the double-pulse test, which is the load voltage in this embodiment. Voltage overshoot indicates that the load voltage exceeds the threshold at the moment of shutdown. When it exceeds the module's maximum withstand voltage, it will cause damage to the module. This is related to the bus voltage, shutdown speed, and stray inductance of the module. The shutdown speed is also affected by the drive resistor, bus voltage, and load current. The stray inductance of the module is determined by the module itself. Therefore, it is necessary to first determine the impact of the drive resistor, bus voltage, and load current (i.e., the current test condition) on the shutdown speed, and then determine the change in load voltage. By planning the test condition sequence of the double-pulse test, the shutdown speed and module stray inductance are calculated and fitted online. Based on the test results of previous operating points, the load voltage of the next operating point is predicted online to determine whether voltage overshoot may occur, thereby achieving circuit protection during the test process.

[0042] Specifically, as described above, the double-pulse test can be used to evaluate switching characteristics, i.e., the switching process of the module from the on state to the off state and from the off state to the on state. It can acquire the dynamic response of the component under different operating states, including on time, off time, rise time, and fall time. The driving resistor can limit the pulse current and affect the rise and fall times of the test pulse, thereby affecting the switching speed and characteristics of the module. The magnitude of the bus voltage and load current also affects the module's response, thus affecting the module's turn-off speed. The driving resistor and / or the bus voltage can be adjusted to perform tests under different test conditions (i.e., adjusting the driving resistor and / or the bus voltage, iteratively executing S100-S500). Therefore, in this embodiment, any two parameters among the driving resistor, bus voltage, and load current are controlled as fixed values, and the other parameter is a variable to form multiple test conditions. For ease of operation, as an example, the driving resistor and the bus voltage (e.g., 190V, 300V, 420V) are controlled as constant values ​​under each condition, and the turn-off speed is determined by changing the load current.

[0043] S200: Under the test conditions, multiple preset operating points are tested, and the load current, load voltage and turn-off speed are collected for each test. Under any operating point, the load voltage does not exceed the threshold.

[0044] In this implementation, it is necessary to predict online whether there is overshoot in the load voltage at a certain operating point, so as to provide accurate online safety margin protection for the double-pulse test. When performing the double-pulse test, under a certain operating condition, the load current is gradually increased at different operating points to determine the change of the turn-off speed with the load current. Under the initial preset test conditions, the load current is small, and the corresponding load voltage should also be small. At this time, it does not exceed the threshold, that is, there will be no voltage overshoot. Under this condition, the parameters (i.e., the load current, load voltage, and turn-off speed mentioned above) are obtained by using the open circuit in the actual test. The curve of the change of the turn-off speed with the load current is determined by the actual obtained load current and turn-off speed for prediction in subsequent steps. As mentioned above, the load voltage is also related to the stray inductance. Furthermore, the stray inductance is calculated based on the actual obtained load voltage and turn-off speed. Since the stray inductance may fluctuate in value in each test, it is also necessary to fit it for calculation in subsequent steps.

[0045] S300: Based on the test of the preset operating points, determine the curve of the change of the turn-off speed with the load current under the test conditions and perform curve fitting. Also calculate the stray inductance under each test to fit and obtain the target stray inductance.

[0046] Specifically, the curve of the turn-off speed versus load current is fitted based on the load current, bus voltage, and drive resistance, i.e., fitted according to the function di / dt = f(Iload, Vdc, Rg) (see [reference]). Figure 2 The curves represent the change in turn-off speed with load current under different bus voltages (e.g., 190V, 300V, 420V) for the same drive resistor, where Iload is the load current, Rg is the drive resistor, and Vdc is the bus voltage. As mentioned above, under a certain operating condition (i.e., the operating condition described above), the bus voltage and drive resistor are constant, forming a curve of the change in turn-off speed with load current. The trends of the curves of the change in turn-off speed with load current are different under different bus voltages and / or different drive resistors. For example, the larger the bus voltage, the steeper the slope of the curve, and the smaller the slope of the curve, the flatter the curve, and the larger the drive resistor, the gentler the slope of the curve.

[0047] Based on the above, in this embodiment, the actual collected parameter values ​​obtained at the beginning of the double pulse test (i.e., the preset operating point) are used to obtain the curve of the change of the turn-off speed with the load current, determine the influence of the load current change on the turn-off speed, and then predict the turn-off speed of the next operating point under this operating condition, so as to predict the load voltage according to the predicted turn-off speed. When the predicted load voltage exceeds the threshold, it stops to perform protection.

[0048] As mentioned above, the load voltage is related to the bus voltage, turn-off speed, and stray inductance of the module. Therefore, an objective function is established to determine the relationship between the bus voltage, load voltage, turn-off speed, and stray inductance, in order to calculate the stray inductance under each test, or to determine the target load voltage as described below. Specifically, the objective function is to obtain the load voltage by summing the product of the turn-off speed and the stray inductance with the bus voltage, according to the following formula: Vover=Vdc+Ls*di / dt; where Vover is the load voltage; Vdc is the bus voltage; Ls is the stray inductance; and di / dt is the turn-off speed.

[0049] For clarification, the stray inductance calculated for each test is based on the actual bus voltage, turn-off speed, and load voltage obtained at the preset operating point. The target load voltage described below is calculated based on the bus voltage, the stray inductance calculated and fitted above, and the turn-off speed corresponding to the target operating point predicted from the curve of turn-off speed versus load current. Since the stray inductance calculated from multiple tests may fluctuate, fitting is also necessary. The stray inductance value obtained after each test, after fitting, represents a straight line with a certain value (see [reference]). Figure 3 ,).

[0050] S400: Obtain the real-time load current corresponding to the target operating point, and determine the target turn-off speed based on the curve of the turn-off speed versus the load current; wherein, the target operating point is an operating point after multiple preset operating points.

[0051] In this embodiment, as described above, during the double-pulse test, the load voltage at subsequent operating points is predicted based on real-time parameter values ​​obtained from multiple initial operating points under a certain operating condition. As in the above steps, calculating the target load voltage requires pre-predicting the turn-off speed corresponding to that operating point (i.e., the target operating point) based on the curve of turn-off speed versus load current. The execution of the target operating point occurs after multiple preset operating points have been executed, meaning the real-time load current is greater than the load current corresponding to the multiple preset operating points, potentially leading to a risk of voltage overshoot.

[0052] S500: Determine the target load voltage based on the bus voltage, target turn-off speed, and target stray inductance; when the target load voltage exceeds the threshold, stop the test of the target operating point.

[0053] In the above steps, the target load voltage is calculated according to the objective function. The threshold is the maximum voltage that the module can withstand. Exceeding the threshold may damage the module. The target stray inductance and the target turn-off speed are obtained by fitting the actual data of historical (i.e. preset) operating points. At the target operating point, if the target load voltage generated by the load current is predicted to exceed the threshold, it indicates that the load current is too large. Therefore, the test process is automatically stopped, realizing accurate online safety protection of the double pulse test process.

[0054] Furthermore, in this embodiment, when the target load voltage does not exceed the threshold, it indicates that the load current corresponding to the target operating point is not too large, and the test can continue. In order to achieve precise control of safety protection, the parameter values ​​tested at the target operating point are collected again, and the above-mentioned curve fitting of the turn-off speed with load current and the fitting process of stray inductance are added in reverse, so that the next operating point is used as the target operating point.

[0055] Specifically, when the target load voltage does not exceed the threshold, a target operating point test is performed to obtain the real-time load voltage and real-time turn-off speed corresponding to the target load current. Based on the real-time turn-off speed, a curve fitting is performed on the curve of the turn-off speed versus the load current. The real-time stray inductance is calculated based on the real-time load voltage and the real-time turn-off speed to adjust the target stray inductance. For reference, the acquired real-time turn-off speed and load current are directly curve-fitted, while the real-time inductance is calculated using the aforementioned objective function.

[0056] In this embodiment, as described above, multiple test conditions can be formed by using any two parameters among the control drive resistor, bus voltage, and load current as fixed parameters and the third parameter as a variable. Different test conditions correspond to different situations leading to voltage overshoot (i.e., different load currents), meaning the predicted results for whether the target operating point is tested differ. Each test condition corresponds to a unique curve showing the change in turn-off speed with load current. However, since stray inductance is related to the module itself, for the same double-pulse test object, the value of stray inductance will eventually fit to a certain value. Therefore, calculating the stray inductance based on tests at multiple operating points under different test conditions and fitting and adjusting the target stray inductance makes the calculated stray inductance more accurate, thereby making the target load voltage calculated based on the stray inductance more accurate during the prediction process, resulting in a more precise protection effect.

[0057] The voltage overshoot protection method for dual-pulse testing provided in this embodiment, by configuring the test condition sequence of dual-pulse testing, calculating the fitting turn-off speed and module stray inductance online, can predict online whether there will be voltage overshoot at the next operating point based on historical test data, thereby providing online safety protection for automated dual-pulse testing and reducing the need for manual monitoring of the testing process; at the same time, it can also perform closed-loop calibration based on the feedback parameters of the actual test, providing accurate prediction results, and can also provide operators with quantitative voltage overshoot margin information based on the target load voltage, that is, by determining the difference between the target load voltage and the threshold.

[0058] Example 2: The present invention also provides a voltage overshoot protection device 6 for dual-pulse testing, which performs the voltage overshoot protection method for dual-pulse testing described in Example 1 above. For details, please refer to... Figure 4 ,include:

[0059] Data acquisition module 61 is used to determine a test condition for dual-pulse automatic testing, wherein the test condition is to adjust the load current for testing under a certain driving resistor and a certain bus voltage; under the test condition, multiple preset test points are performed, and the load current, load voltage and turn-off speed of each test are collected, wherein the load voltage does not exceed the threshold under any test point.

[0060] It should be noted that the online real-time voltage protection provided in this embodiment during the dual-pulse test predicts the load voltage at subsequent operating points (target operating points) based on parameter values ​​obtained from historical (i.e., preset operating points) tests. Therefore, it is necessary to collect parameter values ​​from historical tests. Specifically, during testing, the load current is gradually increased at different operating points to determine how the turn-off speed changes with the load current. In the initial preset operating points, the load current is relatively small, and the corresponding load voltage should also be relatively small, so there will be no voltage overshoot. Therefore, the turn-off speed and module stray inductance are fitted based on the parameters obtained from the actual test to predict the load voltage at the target operating point.

[0061] The calculation module 62 is used to determine the curve of the turn-off speed versus load current under the test conditions based on the test at the preset operating points and to perform curve fitting. It also calculates the stray inductance under each test to fit and obtain the target stray inductance.

[0062] In the above module, the load voltage is related to the bus voltage, turn-off speed, and stray inductance of the module. The turn-off speed is also affected by the drive resistance, bus voltage, and load current. Therefore, based on the parameters obtained from the above acquisition module, the curve of the turn-off speed versus the load current and the stray inductance are fitted. The curve of the turn-off speed versus the load current is fitted based on the turn-off speed and load current obtained from actual tests. The stray inductance needs to be fitted after establishing an objective function calculated based on the turn-off speed and bus voltage. The objective function is the load voltage obtained by summing the product of the turn-off speed and the stray inductance with the bus voltage. Since the stray inductance calculated from multiple tests may have numerical fluctuations, it needs to be fitted. The fitted stray inductance value is a straight line that is approximately located at a certain value.

[0063] Processing module 63 is used to obtain the load current corresponding to the target operating point, and determine the target turn-off speed according to the curve of the turn-off speed changing with the load current; wherein, the target operating point is the operating point after multiple preset operating points; the target load voltage is determined according to the bus voltage, the target turn-off speed and the target stray inductance; when the target load voltage exceeds the threshold, the test of the target operating point is stopped.

[0064] In this module, the turn-off speed at the target operating point is predicted based on the curve of the turn-off speed changing with the load current. Then, the target load voltage is calculated using the objective function. This threshold is the maximum voltage that the module can withstand. Exceeding this threshold may damage the module. Therefore, the test process is stopped to protect the module.

[0065] Furthermore, this module can also perform the following steps: if the target load voltage does not exceed the threshold, indicating that the load current corresponding to the target operating point is not too large, the test can continue. The module collects the parameter values ​​tested at the target operating point and reverses the aforementioned curve fitting process of turn-off speed versus load current and stray inductance fitting, while simultaneously determining the next target operating point. Thus, by calculating and fitting the turn-off speed and module stray inductance online, and based on the actual test results of historical (preset operating points), it predicts online whether there will be voltage overshoot at the next operating point, thereby providing online safety protection for dual-pulse automated testing.

[0066] Example 3: This invention also provides a dual-pulse testing system, which applies the voltage overshoot protection device for dual-pulse testing described in Example 2 to automatically perform dual-pulse testing. Dual-pulse testing is a testing method used to evaluate the performance and characteristics of semiconductor components (such as transistors, diodes, etc.). It also includes other components and / or modules used to perform dual-pulse testing, which will not be elaborated here. It is used to perform operations such as switching characteristic evaluation, dynamic response analysis, energy consumption evaluation, life and reliability testing, performance parameter extraction, and fault diagnosis. The test condition sequence of dual-pulse testing can be pre-planned for automatic testing. During this process, the voltage overshoot protection device for dual-pulse testing described in Example 2 executes the voltage overshoot protection method described in Example 1. During the dual-pulse testing process, it autonomously predicts whether there will be overshoot at each subsequent operating point. If there is a possibility of overshoot, the test is stopped to improve the safety of the dual-pulse testing process and reduce the possibility of module damage due to voltage overshoot.

[0067] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A voltage overshoot protection method using a dual-pulse test, characterized in that, include: A test condition for a double-pulse test is determined, wherein the test condition is to adjust the load current under a certain driving resistor and a certain bus voltage. Multiple test conditions are formed by controlling any two parameters of the driving resistor, bus voltage and load current as fixed parameters and the other parameter as a variable. Under the test conditions, multiple preset operating points were tested, and the load current, load voltage and turn-off speed were collected for each test. Under any operating point, the load voltage did not exceed the threshold. Based on the tests at the multiple preset operating points, the curve of the turn-off speed versus the load current under the test conditions is determined and curve fitting is performed. The stray inductance under each test is also calculated to fit and obtain the target stray inductance. Obtain the real-time load current corresponding to the target operating point, and determine the target turn-off speed based on the curve of the turn-off speed versus the load current; wherein, the target operating point is an operating point after multiple preset operating points. The target load voltage is determined based on the bus voltage, the target turn-off speed, and the target stray inductance. When the target load voltage exceeds the threshold, the test of the target operating point is stopped; Establish an objective function to determine the relationship between bus voltage, load voltage, turn-off speed, and stray inductance, in order to calculate the stray inductance for each test or determine the target load voltage; The objective function is to obtain the load voltage by summing the product of the turn-off speed and stray inductance with the bus voltage; If the target load voltage does not exceed the threshold, the target operating point test is performed to obtain the real-time load voltage and real-time shutdown speed corresponding to the target load current. Based on the real-time shutdown speed, the curve of the shutdown speed versus load current is fitted. The real-time stray inductance is calculated based on the real-time load voltage and real-time turn-off speed, and the target stray inductance is fitted and adjusted.

2. The voltage overshoot protection method according to claim 1, characterized in that: The curve of the turn-off speed versus load current is fitted based on the load current, bus voltage, and drive resistance.

3. The voltage overshoot protection method according to claim 1, characterized in that: Adjust the driving resistor / bus voltage to conduct tests under different test conditions.

4. The voltage overshoot protection method according to claim 3, characterized in that: The stray inductance is calculated based on the test results at multiple operating points under different test conditions, and the target stray inductance is fitted and adjusted.

5. A voltage overshoot protection device for dual-pulse testing, characterized in that, include: The data acquisition module is used to determine a test condition for the dual-pulse test, wherein the test condition involves adjusting the load current under a certain driving resistor and a certain bus voltage; under the test condition, multiple preset test points are tested, and the load current, load voltage and turn-off speed are collected for each test, wherein the load voltage does not exceed the threshold under any test point. Multiple test conditions are formed by controlling any two parameters of the driving resistor, bus voltage and load current as quantitative and the other parameter as variable. The calculation module is used to determine the curve of the turn-off speed versus load current under the test conditions based on the test of the multiple preset operating conditions and to perform curve fitting. It also calculates the stray inductance under each test to fit and obtain the target stray inductance. The processing module is used to acquire the real-time load current corresponding to the target operating point, and determine the target turn-off speed based on the curve of the turn-off speed versus the load current; wherein, the target operating point is an operating point after multiple preset operating points; the target load voltage is determined based on the bus voltage, the target turn-off speed, and the target stray inductance; when the target load voltage exceeds the threshold, the test of the target operating point is stopped. Establish an objective function to determine the relationship between bus voltage, load voltage, turn-off speed, and stray inductance, in order to calculate the stray inductance for each test or determine the target load voltage; The objective function is to obtain the load voltage by summing the product of the turn-off speed and stray inductance with the bus voltage; If the target load voltage does not exceed the threshold, the target operating point test is performed to obtain the real-time load voltage and real-time shutdown speed corresponding to the target load current. Based on the real-time shutdown speed, the curve of the shutdown speed versus load current is fitted. The real-time stray inductance is calculated based on the real-time load voltage and real-time turn-off speed, and the target stray inductance is fitted and adjusted.

6. A dual-pulse testing system, characterized in that: The voltage overshoot protection device for the double-pulse test as described in claim 5 is used to automatically perform the double-pulse test.

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