Insulation resistance test method for IGBT module

Abstract

The invention discloses an insulation resistance test method for an IGBT (Insulated Gate Bipolar Translator) module, and relates to the field of power electronic systems. The insulation resistance test method for the IGBT module comprises the following steps: determining environment variable parameters, configuring a test voltage variable, applying a test voltage to the IGBT module, recording a test time variable, and testing the voltage variable and the test time variable based on different environment variable parameters. According to the insulation resistance test method for the IGBT module, multiple voltage test variables are set, the initial voltage can be self-adapted, the strictly controlled voltage output error is matched, the absolute value of the output error does not exceed 0.5%, the leakage current is measured by adopting a four-wire method, and the current measurement error is controlled in a minimum range; the error absolute value of the current measuring instrument does not exceed 1%, and the accuracy of insulation resistance calculation is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of power electronic systems technology, specifically to a method for testing the insulation resistance of IGBT modules. Background Technology

[0002] As a key component in power electronic systems, the insulation performance of IGBT (Insulated Gate Bipolar Transistor) modules directly affects the safety and reliability of the entire system. In practical applications, IGBT modules often operate in complex and variable environments, such as different temperatures, humidity levels, and air pressures, where environmental factors can significantly impact their insulation resistance.

[0003] In the existing technology, insulation resistance testing methods are mainly divided into the following categories: Fixed voltage instantaneous test method: A single fixed voltage (such as 500V or 1000V) is applied to the IGBT module, and the leakage current is measured and the insulation resistance is calculated within a short time (usually 10-15s). This method is simple to operate and fast, and is widely used in rapid sampling inspection on production lines. However, it does not consider the dynamic effect of voltage stress on insulation performance and is difficult to reflect the insulation characteristics of the module under different voltage levels. Multi-voltage segmented testing method: This method tests using 2-3 discrete voltage values. While it expands the voltage coverage to some extent, the voltage settings lack a systematic pattern and do not adaptively adjust for the rated voltage of the IGBT module, resulting in insufficient testing specificity for high-rated voltage modules. The constant environment test method: The test is conducted in a constant temperature and humidity chamber, which ignores the fluctuation characteristics of environmental parameters in actual applications and does not establish a quantitative correlation model between environmental error and insulation resistance. Therefore, the test results deviate from the actual working conditions. Simplified error control method: Only the voltage source and ammeter are calibrated periodically, without considering the influence of the test line resistance, contact resistance and stray capacitance. Especially in high voltage test (≥1500V) scenarios, the leakage current measurement error often exceeds ±3%, resulting in insufficient accuracy of insulation resistance calculation. Traditional insulation resistance testing methods do not fully consider the interference of environmental variables on the test results, and the control precision of measurement errors during the testing process is insufficient. Furthermore, existing technologies often lack systematic error analysis and correction methods, and the judgment of insulation performance is based only on a single time point or simple indicators, making it difficult to comprehensively and accurately assess the long-term insulation stability of IGBT modules under different operating conditions. With the development of power electronics technology, the performance requirements of IGBT modules are constantly increasing, urgently requiring a testing method that can accurately measure and comprehensively evaluate insulation resistance, and effectively eliminate interference from environmental and measurement errors. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for testing the insulation resistance of IGBT modules, solving the problems of inaccurate test results due to environmental interference, imperfect error analysis and correction, and one-sided judgment of insulation performance in existing testing methods.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for testing the insulation resistance of an IGBT module, comprising the following steps: S1. Determine the environmental variable parameters, specifically including ambient temperature. Ambient humidity and ambient air pressure And set the corresponding threshold ranges, i.e., temperature threshold ranges. Humidity threshold range air pressure threshold range High-precision temperature and humidity sensors and barometric pressure sensors are used to monitor the environmental variables in real time, and the measurement error range of each sensor is recorded synchronously. , and ; S2, Configure test voltage variables The test voltage variable covers multiple discrete voltage values, which are distributed in an arithmetic or geometric manner within the range of 500V-2500V. It can also adaptively adjust the initial test voltage value according to the rated voltage of the IGBT module and record the output error of the test voltage source. The output error The absolute value does not exceed 0.5%; S3. Apply the test voltage to the IGBT module and record the test time variable. The test time variable includes three characteristic time nodes: the first time node is 30s, used for preliminary evaluation of insulation performance; the second time node is 60s, used for analyzing insulation resistance stability; and the third time node is 120s, used for detecting changes in insulation characteristics under long-term voltage stress, and the error of the time recording device. The absolute value does not exceed 0.1s; S4. Based on different environmental variables, test voltage variables, and test time variables, the corresponding leakage current is obtained using the four-wire measurement method. Insulation resistance calculation formula Calculate insulation resistance value To eliminate the influence of test circuit resistance and contact resistance, among which For the applied test voltage, The error of the current measuring instrument is used to measure the leakage current. The absolute value does not exceed 1%.

[0006] Preferably, after step S4, an environmental parameter error correction step is further provided: an environmental error correction model is established experimentally to correct the insulation resistance measurement value, wherein the correction model is: ,in , and These are error correction factors for temperature, humidity, and air pressure, respectively, which are determined through calibration experiments on standard resistors.

[0007] Preferably, an error analysis step is provided after the environmental parameter error correction step, specifically as follows: The absolute error in calculating insulation resistance according to the error propagation formula : ,in For voltage error, For current error, For testing voltage, Leakage current; The relative error of insulation resistance is calculated according to the formula. : The relative error is required. The absolute value should not exceed 5%. If it exceeds this range, the measuring instrument needs to be recalibrated and the test procedure repeated.

[0008] Preferably, a judgment logic 1 is constructed between steps S2 and S3: When the ambient temperature is The range and ambient humidity are at The range and the ambient air pressure are at When the test is within a certain range, the test environment is deemed to meet the basic requirements; simultaneously, the absolute error of the environmental parameters must meet a preset threshold. The absolute value is ≤1℃. The absolute value is ≤3%. If the absolute value is ≤50Pa, the test is terminated and the environmental parameters are adjusted using environmental control equipment.

[0009] Preferably, after the error analysis step, judgment logic 2 is constructed: For each test voltage value, when the test time reaches the first time node, if the insulation resistance value after error correction... Greater than or equal to the first resistance threshold determined according to the IGBT module's rated parameters and industry standards. And relative error If the absolute value is ≤5%, then continue the test; if Less than or If the absolute value is greater than 5%, it is preliminarily determined that the insulation performance of the IGBT module is abnormal or that the measurement system is faulty, and the preliminary fault diagnosis procedure is initiated.

[0010] Preferably, construct judgment logic 3: In the scenario where testing continues in logic 2, when the test time reaches the second time node, the insulation resistance values ​​after error correction are calculated for both time nodes. and Through the formula of rate of change Calculate the rate of change At the same time, calculate the error of the rate of change. : If the rate of change Less than or equal to the preset rate of change threshold and If the absolute value of the value is ≤1%, the insulation performance of the IGBT module is determined to be stable under the test voltage; otherwise, it is determined to be unstable.

[0011] Preferably, construct judgment logic 4: When the test reaches the third time point, calculate the insulation resistance value at the third time point after error correction. Through the descent rate formula Calculate the descent rate and the rate error. If the insulation resistance shows a continuous decreasing trend and the rate of decrease exceeds a preset threshold, and If the absolute value is ≤0.5MΩ / s, then a long-term stability problem is identified.

[0012] Preferably, the pass / fail determination is made by combining the judgment results under all test voltages: if the IGBT module meets the requirements of stable insulation performance, no preliminary abnormal judgment, no long-term stability problems under all test voltages, and the absolute value of the relative error of all measurements is ≤5%, then the insulation resistance of the IGBT module is judged to be qualified; otherwise, it is judged to be unqualified; for unqualified modules, a detailed fault report containing error analysis data and possible fault causes is generated.

[0013] Preferably, the environmental control equipment has an automatic calibration function, which can periodically correct the errors of the temperature and humidity sensors and the barometric pressure sensor, so that the corrected measurement error meets the following requirements: The absolute value is ≤0.5℃. The absolute value is ≤2%. The absolute value of the voltage is ≤30Pa; the test voltage source adopts a closed-loop feedback control mechanism to monitor the output voltage in real time and correct errors, ensuring that the output error is minimized. The absolute value of the leakage current is ≤0.2%; the leakage current measurement adopts the multiple sampling averaging method, with no less than 10 sampling times, to reduce the impact of random errors. The impact.

[0014] Preferably, for high-voltage testing scenarios of ≥1500V, the impact of stray capacitance of the high-voltage leads on current measurement needs to be additionally considered, and a capacitance compensation algorithm should be used to address this. Corrections are made to compensate for the absolute value of the error ≤ 0.5%; time node error The error calculation for the descent rate needs to be included. The corrected rate error formula is as follows: Error analysis data must be stored in real time and be traceable. The stored content includes the original data of each measurement, error parameters, and records of the correction process.

[0015] Its beneficial effects are as follows: 1. This insulation resistance testing method for IGBT modules, by setting multiple voltage test variables and adapting to the initial voltage, combined with strictly controlled voltage output error, results in a low output error. The absolute value does not exceed 0.5%, and the leakage current is measured using the four-wire method with the current measurement error controlled to a minimum. The error of the current measuring instrument... The absolute value does not exceed 1%, which greatly improves the accuracy of insulation resistance calculation.

[0016] 2. The insulation resistance test method for IGBT modules establishes an environmental error correction model. Based on the temperature, humidity, and air pressure correction coefficients determined by experiments, the measured values ​​are corrected, effectively eliminating the influence of environmental factors on insulation resistance measurement, and making the test results more consistent with the actual insulation condition of IGBT modules during operation.

[0017] 3. The insulation resistance test method for IGBT modules has a four-fold judgment logic, which gradually and comprehensively judges the insulation performance of IGBT modules from test environment judgment, preliminary insulation performance evaluation, insulation stability analysis to long-term stability testing. This greatly improves the accuracy and reliability of insulation performance evaluation and can promptly detect potential insulation abnormalities and long-term stability problems.

[0018] 4. This insulation resistance testing method for IGBT modules strictly limits various measurement errors and further reduces them through techniques such as automatic calibration, closed-loop feedback control, and multiple sampling averaging. Simultaneously, error analysis data is stored long-term for easy traceability and analysis, providing strong evidence for product quality improvement and troubleshooting. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is one of the overall process diagrams of the present invention; Figure 2 This is the second schematic diagram of the overall process of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0023] This invention discloses a method for testing the insulation resistance of IGBT modules, according to the appendix. Figure 1-2 As shown, it includes the following steps: S1. Determine the environmental variable parameters, specifically including ambient temperature. Ambient humidity and ambient air pressure And set the corresponding threshold ranges, i.e., temperature threshold ranges. Humidity threshold range air pressure threshold range High-precision temperature and humidity sensors and barometric pressure sensors are used to monitor environmental variables in real time, and the measurement error range of each sensor is recorded simultaneously. , and ; S2, Configure test voltage variables The test voltage variables cover multiple discrete voltage values, which are distributed in an arithmetic or geometric manner within the range of 500V-2500V. Furthermore, the initial test voltage value can be adaptively adjusted according to the rated voltage of the IGBT module, and the output error of the test voltage source is recorded. Output error The absolute value does not exceed 0.5%; S3. Apply a test voltage to the IGBT module and record the test time variable. The test time variable includes three characteristic time nodes: the first time node is 30s, used for preliminary assessment of insulation performance; the second time node is 60s, used for analyzing insulation resistance stability; and the third time node is 120s, used for detecting changes in insulation characteristics under long-term voltage stress. Errors in the time recording device are also considered. The absolute value does not exceed 0.1s; S4. Based on different environmental variables, test voltage variables, and test time variables, the corresponding leakage current is obtained using the four-wire measurement method. Insulation resistance calculation formula Calculate insulation resistance value To eliminate the influence of test circuit resistance and contact resistance, among which For the applied test voltage, The error of the current measuring instrument is used to measure the leakage current. The absolute value does not exceed 1%.

[0024] By setting multiple voltage test variables and adapting to the initial voltage, coupled with strictly controlled voltage output error, the output error... The absolute value does not exceed 0.5%, and the leakage current is measured using the four-wire method with the current measurement error controlled to a minimum. The error of the current measuring instrument... The absolute value does not exceed 1%, which greatly improves the accuracy of insulation resistance calculation.

[0025] Following step S4, an environmental parameter error correction step is included: an environmental error correction model is established experimentally to correct the insulation resistance measurement value. The correction model is as follows: ,in , and These are the error correction factors for temperature, humidity, and air pressure, respectively. The correction factors are determined through calibration experiments on standard resistors.

[0026] An environmental error correction model is established, and the measured values ​​are corrected based on the temperature, humidity, and air pressure correction coefficients determined by experiments. This effectively eliminates the influence of environmental factors on insulation resistance measurement, making the test results more consistent with the actual insulation condition of the IGBT module during operation.

[0027] An error analysis step is set after the environmental parameter error correction step, specifically as follows: The absolute error in calculating insulation resistance according to the error propagation formula : ,in For voltage error, For current error, For testing voltage, Leakage current; The relative error of insulation resistance is calculated according to the formula. : Relative error required The absolute value should not exceed 5%. If it exceeds this range, the measuring instrument needs to be recalibrated and the test procedure repeated.

[0028] Logic 1 for determining the relationship between steps S2 and S3: When the ambient temperature is The range and ambient humidity are at The range and the ambient air pressure are at When the test is within a certain range, the test environment is deemed to meet the basic requirements; simultaneously, the absolute error of the environmental parameters must meet a preset threshold. The absolute value is ≤1℃. The absolute value is ≤3%. If the absolute value is ≤50Pa, the test is terminated and the environmental parameters are adjusted using environmental control equipment.

[0029] After the error analysis step, construct judgment logic 2: For each test voltage value, when the test time reaches the first time node, if the insulation resistance value after error correction... Greater than or equal to the first resistance threshold determined according to the IGBT module's rated parameters and industry standards. And relative error If the absolute value is ≤5%, then continue the test; if Less than or If the absolute value is greater than 5%, it is preliminarily determined that the insulation performance of the IGBT module is abnormal or that the measurement system is faulty, and the preliminary fault diagnosis procedure is initiated.

[0030] Construct judgment logic 3: In the scenario where testing continues in logic 2, when the test time reaches the second time node, the insulation resistance values ​​after error correction are calculated for both time nodes. and Through the formula of rate of change Calculate the rate of change At the same time, calculate the error of the rate of change. : If the rate of change Less than or equal to the preset rate of change threshold and If the absolute value of the value is ≤1%, the insulation performance of the IGBT module is determined to be stable under the test voltage; otherwise, it is determined to be unstable.

[0031] Construct judgment logic 4: When the test reaches the third time point, calculate the insulation resistance value at the third time point after error correction. Through the descent rate formula Calculate the descent rate and the rate error. If the insulation resistance shows a continuous decreasing trend and the rate of decrease exceeds the preset threshold, and If the absolute value is ≤0.5MΩ / s, then a long-term stability problem is identified.

[0032] The pass / fail status is determined by combining the results of all test voltages: if the IGBT module meets the requirements of stable insulation performance, no preliminary abnormality, no long-term stability issues, and the absolute value of the relative error of all measurements is ≤5% under all test voltages, then the insulation resistance of the IGBT module is deemed qualified; otherwise, it is deemed unqualified; for unqualified modules, a detailed fault report containing error analysis data and possible causes of failure is generated.

[0033] A four-tiered judgment logic was constructed, which proceeds from test environment judgment, preliminary insulation performance assessment, insulation stability analysis to long-term stability testing, to gradually and comprehensively determine the insulation performance of IGBT modules, greatly improving the accuracy and reliability of insulation performance assessment and enabling timely detection of potential insulation anomalies and long-term stability issues.

[0034] The environmental control equipment has an automatic calibration function, which can periodically correct the errors of the temperature and humidity sensors and the barometric pressure sensor, so that the corrected measurement error meets the following requirements: The absolute value is ≤0.5℃. The absolute value is ≤2%. The absolute value of the voltage is ≤30Pa; the test voltage source adopts a closed-loop feedback control mechanism to monitor the output voltage in real time and correct errors, ensuring that the output error is minimized. The absolute value of the leakage current is ≤0.2%; the leakage current measurement adopts the multiple sampling averaging method, with no less than 10 sampling times, to reduce the impact of random errors. The impact.

[0035] For high-voltage testing scenarios (≥1500V), the impact of stray capacitance of the high-voltage leads on current measurement needs to be considered, and a capacitance compensation algorithm should be used. Corrections are made to compensate for the absolute value of the error ≤ 0.5%; time node error The error calculation for the descent rate needs to be included. The corrected rate error formula is as follows: Error analysis data must be stored in real time and be traceable. The stored content includes the original data of each measurement, error parameters, and records of the correction process.

[0036] Various measurement errors are strictly limited, and further reduced through techniques such as automatic calibration, closed-loop feedback control, and multiple sampling averaging. Simultaneously, error analysis data is stored long-term for easy traceability and analysis, providing strong evidence for product quality improvement and troubleshooting.

[0037] Overall workflow: Phase 1: Preparation Phase Based on the characteristics of IGBT modules and relevant standards, environmental variables (ambient temperature) are determined. Ambient humidity and ambient air pressure Threshold range (temperature threshold range) Humidity threshold range air pressure threshold range ), and deploy high-precision temperature, humidity, and air pressure sensors to monitor environmental parameters in real time and record measurement errors ( , and ). Configure test voltage variables Multiple discrete voltage values ​​are set in the 500V-2500V range according to an arithmetic or geometric progression, and the initial test voltage is automatically adjusted according to the rated voltage of the IGBT module, while ensuring the output error of the test voltage source. The absolute value does not exceed 0.5%.

[0038] Phase Two: Environmental Compliance Verification (Judgment Logic 1) Real-time monitoring of environmental parameters to check whether they are within preset threshold ranges. Verify the measurement error of environmental parameters ( The absolute value is ≤1℃. The absolute value is ≤3%. (Absolute value ≤ 50 Pa) If the requirements are not met, activate the environmental conditioning equipment for adjustment; if the requirements are met, proceed to the test execution phase. Phase 3: Test Execution Phase Apply a test voltage to the IGBT module and record the test time at three specific time points: 30s, 60s, and 120s. To ensure time recording error The absolute value does not exceed 0.1s. Using the four-wire measurement method, the corresponding leakage current is measured for different environmental, voltage, and time parameters. and through Calculate insulation resistance value Control current measurement error The absolute value does not exceed 1%.

[0039] Phase Four: Data Processing Phase The insulation resistance measurement value is corrected using an environmental error correction model to obtain the corrected insulation resistance value. .

[0040] The absolute error in calculating insulation resistance based on the error propagation formula. and relative error If the relative error If the absolute value exceeds 5%, the measuring instrument should be calibrated and retested; if it passes, the performance judgment stage begins.

[0041] Phase 5: Performance Assessment Based on judgment logic 2, at 30s, determine whether to continue testing or start fault diagnosis based on R correction and δR. If logic 2 allows the test to continue, at 60 seconds, based on logic 3, the insulation resistance change rate is calculated. and error Determine whether the insulation performance is stable.

[0042] Finally, at 120 seconds, based on judgment logic 4, the descent rate is calculated. and error Determine if there are any long-term stability issues. Phase Six: Comprehensive Judgment and Result Output Based on the combined results of all test voltages, if the IGBT module meets the requirements of stable insulation, no abnormalities, no long-term stability issues, and the absolute value of the relative error of all measurements is ≤5% under all test voltages, it is deemed qualified; otherwise, it is deemed unqualified, and a detailed report containing error data and fault causes is generated.

[0043] Phase Seven: Data Management and Equipment Maintenance Store raw data, error parameters, and correction records (for at least 3 years). Activate the automatic calibration function of the environmental conditioning equipment and the closed-loop feedback control of the voltage source. Stray capacitance compensation is performed for high-voltage testing scenarios.

[0044] It is important to emphasize that environmental control equipment should periodically and automatically calibrate sensors to ensure that measurement errors meet the requirements. Absolute value ≤ 0.5℃ Absolute value ≤ 2%, Absolute value ≤30Pa; the test voltage source uses closed-loop feedback control to minimize output error. The absolute value is ≤0.2%; the leakage current measurement adopts the sampling averaging method of no less than 10 times.

[0045] For high-voltage testing scenarios of ≥1500V, current measurement errors are corrected using a capacitor compensation algorithm. The absolute value of the compensation error is ≤0.5%; the time node error is compensated. By incorporating the descent rate error calculation, the corrected rate error is obtained. Simultaneously, error analysis data, including raw data, error parameters, and correction records, is stored in real time for a period of no less than 3 years.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for testing the insulation resistance of an IGBT module, characterized in that, Includes the following steps: S1. Determine the environmental variable parameters, specifically including ambient temperature. Ambient humidity and ambient air pressure And set the corresponding threshold ranges, i.e., temperature threshold ranges. Humidity threshold range air pressure threshold range High-precision temperature and humidity sensors and barometric pressure sensors are used to monitor the environmental variables in real time, and the measurement error range of each sensor is recorded synchronously. , and ; S2, Configure test voltage variables The test voltage variable covers multiple discrete voltage values, which are distributed arithmetically or geometrically within the range of 500V-2500V. It can adaptively adjust the initial test voltage value according to the rated voltage of the IGBT module and record the output error of the test voltage source. The output error The absolute value does not exceed 0.5%; S3. Apply the test voltage to the IGBT module and record the test time variable. The test time variable includes three characteristic time nodes: the first time node is 30s, used for preliminary evaluation of insulation performance; the second time node is 60s, used for analyzing insulation resistance stability; and the third time node is 120s, used for detecting changes in insulation characteristics under long-term voltage stress, and the error of the time recording device. The absolute value does not exceed 0.1s; S4. Based on different environmental variables, test voltage variables, and test time variables, the corresponding leakage current is obtained using the four-wire measurement method. Insulation resistance calculation formula Calculate insulation resistance value ,in For the applied test voltage, The error of the current measuring instrument is used to measure the leakage current. The absolute value does not exceed 1%.

2. The insulation resistance testing method for IGBT modules according to claim 1, characterized in that, Following step S4, an environmental parameter error correction step is included: an environmental error correction model is established experimentally to correct the insulation resistance measurement value. The correction model is as follows: ,in , and These are error correction factors for temperature, humidity, and air pressure, respectively, which are determined through calibration experiments on standard resistors.

3. The insulation resistance testing method for IGBT modules according to claim 2, characterized in that, An error analysis step is set after the environmental parameter error correction step, specifically as follows: The absolute error in calculating insulation resistance according to the error propagation formula : ,in For voltage error, For current error, For testing voltage, Leakage current; The relative error of insulation resistance is calculated according to the formula. : The relative error is required. The absolute value should not exceed 5%. If it exceeds this range, the measuring instrument needs to be recalibrated and the test procedure repeated.

4. The insulation resistance testing method for IGBT modules according to claim 1, characterized in that, The judgment logic 1 between steps S2 and S3 is as follows: When the ambient temperature is The range and ambient humidity are at The range and the ambient air pressure are at When the test is conducted within a certain range, the test environment is deemed to meet the basic requirements; simultaneously, the absolute error of the environmental parameters must meet a preset threshold. The absolute value is ≤1℃. The absolute value is ≤3%. If the absolute value is ≤50Pa, the test is terminated and the environmental parameters are adjusted using environmental control equipment.

5. The insulation resistance testing method for an IGBT module according to claim 3, characterized in that, After the error analysis step, construct judgment logic 2: For each test voltage value, when the test time reaches the first time node, if the insulation resistance value after error correction... Greater than or equal to the first resistance threshold And relative error If the absolute value is ≤5%, then continue the test; if Less than or If the absolute value is greater than 5%, it is preliminarily determined that the insulation performance of the IGBT module is abnormal or that the measurement system is faulty, and the preliminary fault diagnosis procedure is initiated.

6. The insulation resistance testing method for an IGBT module according to claim 5, characterized in that, Construct judgment logic 3: In the scenario where testing continues in logic 2, when the test time reaches the second time node, the insulation resistance values ​​after error correction are calculated for both time nodes. and Through the formula of rate of change Calculate the rate of change At the same time, calculate the error of the rate of change. : If the rate of change Less than or equal to the preset rate of change threshold and If the absolute value of the value is ≤1%, the insulation performance of the IGBT module is determined to be stable under the test voltage; otherwise, it is determined to be unstable.

7. The insulation resistance testing method for an IGBT module according to claim 6, characterized in that, Construct judgment logic 4: When the test reaches the third time point, calculate the insulation resistance value at the third time point after error correction. Through the descent rate formula Calculate the descent rate and the rate error. If the insulation resistance shows a continuous decreasing trend and the rate of decrease exceeds the preset threshold, and If the absolute value is ≤0.5MΩ / s, then a long-term stability problem is identified.

8. The insulation resistance testing method for IGBT modules according to claim 1, characterized in that, The pass / fail status is determined by combining the results of all test voltages: if the IGBT module meets the requirements of stable insulation performance, no preliminary abnormality, no long-term stability issues, and the absolute value of the relative error of all measurements is ≤5% under all test voltages, then the insulation resistance of the IGBT module is deemed qualified; otherwise, it is deemed unqualified; for unqualified modules, a detailed fault report containing error analysis data and possible causes of failure is generated.

9. The insulation resistance testing method for an IGBT module according to claim 4, characterized in that, The environmental control equipment has an automatic calibration function, which can periodically correct the errors of the temperature and humidity sensors and the barometric pressure sensor, so that the corrected measurement error meets the following requirements: The absolute value is ≤0.5℃. The absolute value is ≤2%. The absolute value is ≤30Pa; The test voltage source employs a closed-loop feedback control mechanism to monitor the output voltage in real time and correct for errors, thus minimizing output error. The absolute value is ≤0.2%.

10. The insulation resistance testing method for an IGBT module according to claim 1, characterized in that, For high-voltage testing scenarios ≥1500V, a capacitor compensation algorithm is used. Corrections are made to compensate for the absolute value of the error ≤ 0.5%; time node error The error calculation for the descent rate needs to be included. The corrected rate error formula is as follows: Error analysis data must be stored in real time and be traceable. The stored content includes the original data of each measurement, error parameters, and records of the correction process.

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