Non-contact working parameter measurement method for IGBT (Insulated Gate Bipolar Translator) chip

Abstract

The invention belongs to the technical field of IGBT chips, and discloses a non-contact working parameter measurement method for an IGBT chip, and the method comprises the following specific steps: 1, building a simulation model, building an electromagnetic field model of the IGBT chip through modeling software, simulating the electromagnetic field distribution under different working conditions according to the built electromagnetic field model of the IGBT chip, and recording the electromagnetic field distribution; according to the method, non-contact electromagnetic method measurement of the IGBT chip is achieved by establishing the IGBT chip electromagnetic field model, damage or interference possibly caused by physical contact is avoided, working parameters are indirectly obtained by continuously monitoring electromagnetic field changes in the normal working process of the IGBT chip in real time, and the reliability of the IGBT chip is improved. Therefore, weak electromagnetic field changes in the switching transient process can be detected and converted into accurate electric signals, meanwhile, the wide frequency range of the IGBT chip from low frequency to high frequency can be covered, and the measurement requirements of the IGBT chip under different working conditions are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of IGBT chips, and specifically relates to a non-contact working parameter measurement method for IGBT chips. Background Art

[0002] As a core power semiconductor device in new energy systems, IGBT (Insulated Gate Bipolar Transistor) is like the "heart" of the new energy industry, playing a crucial role in the conversion and control of electrical energy. In a photovoltaic power generation system, the IGBT module precisely regulates the direct current generated by photovoltaic cells, efficiently converting it into stable alternating current and integrating it into the power grid; in the field of wind power generation, with its excellent fast-switching characteristics and high-power processing capabilities, IGBT ensures that wind turbines can stably output high-quality electrical energy under complex and variable wind speed conditions; in the field of new energy vehicles, IGBT is an indispensable key component in the motor drive and battery management systems, directly determining the vehicle's power performance, driving range, and charging efficiency.

[0003] The accurate measurement of IGBT chip working parameters is crucial for device performance evaluation, reliability analysis, and system optimization. However, as IGBT chips develop towards higher voltages, larger currents, and higher frequencies, traditional measurement methods are no longer applicable. Currently, IGBT working parameter measurement techniques mainly rely on contact measurements, directly contacting the chip surface or pins through physical probes, relying on equipment such as oscilloscopes, shunt resistors, and thermocouples. However, the insertion of probes will introduce parasitic inductance and capacitance, resulting in measurement signal distortion, especially significant errors in high-frequency switching states. In addition, the bandwidth of traditional instruments is limited, making it difficult to capture nanosecond-level switching transient processes. Moreover, for modularly packaged IGBTs, the internal chip parameters cannot be directly measured, and the module needs to be disassembled, which is likely to damage the device structure. Therefore, it is necessary to improve the measurement method. Summary of the Invention

[0004] The purpose of the present invention is to provide a non-contact working parameter measurement method for IGBT chips to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A non-contact working parameter measurement method for IGBT chips, the specific steps are as follows:

[0006] Step 1: Establish a simulation model

[0007] Use modeling software to establish an electromagnetic field model of the IGBT chip, and then, based on the established electromagnetic field model of the IGBT chip, simulate the electromagnetic field distribution under different working conditions and record it;

[0008] Step 2: Prepare the test environment

[0009] Select a suitable test site and measurement equipment, then arrange the test platform and fix the IGBT chip on the test platform;

[0010] Step 3: Determine the measurement positions

[0011] Select suitable measurement positions around the IGBT chip and place the measurement equipment prepared in Step 2;

[0012] Step 4: Measure the changes in the electromagnetic field

[0013] Use the measurement equipment to measure the changes in the electromagnetic field around the IGBT chip when it is working. According to Faraday's law of electromagnetic induction, when a coil is in a changing magnetic field, an induced electromotive force will be generated in the coil. By measuring the induced electromotive force, the rate of change of the magnetic field can be calculated, and then the magnetic field strength can be obtained;

[0014] Step 5: Establish the relationship between the electromagnetic field and the operating parameters of the IGBT chip

[0015] Based on the electromagnetic field theory, analyze the relationship between the changes in the electromagnetic field when the IGBT chip is working and its voltage and current operating parameters;

[0016] Step 6: Calculate the operating parameters of the IGBT chip

[0017] Calculate the operating parameters of the IGBT chip according to the relationship between the electromagnetic field and the operating parameters of the IGBT chip established in Step 5.

[0018] As a preferred technical solution of the present invention, the modeling software described in step one uses COMSOL Multiphysics. When modeling, import the pre-drawn IGBT chip CAD file to create the IGBT chip geometric model. When performing static electric field analysis, the mesh size is set to 0.1 μm in the gate region and 10 μm in other regions; the boundary conditions are set to anode / cathode Ohmic contact and gate voltage excitation; the solver is the MUMPS direct solver; when performing transient switching characteristic analysis, the mesh size is set to 0.5 μm in the channel region and 5 μm in other regions; the boundary conditions are set to anode pulse voltage, cathode grounded, and gate drive signal; the solver is BDF time stepping + GMRES iteration. After the IGBT chip geometric model is created, select the electromagnetic field module in COMSOL Multiphysics to analyze and establish the electromagnetic field model of the IGBT chip. Finally, simulate the electromagnetic field distributions under the two different operating conditions of conduction and turn-off and record them. After the simulation is completed, use the measuring device described in step two to actually measure the electromagnetic field intensity under the same simulation conditions, and then compare the measured value with the simulation result to verify the model accuracy. If the results are consistent, it indicates that the electromagnetic field model of the IGBT chip is successfully established, and the electromagnetic field model of the IGBT chip is verified to be qualified. If the results are inconsistent, repeat the operations in step one to re-model.

[0019] As a preferred technical solution of the present invention, the test site described in step two is an electromagnetic shielding room. The measuring device described in step two includes a detection coil, a spectrum analyzer, an oscilloscope, and a low-pass filter. The spectrum analyzer sets the measurement frequency range according to the operating frequency of the IGBT chip before use. The oscilloscope sets the sampling rate according to the measurement requirements before use. The detection coil is calibrated with a standard source with a known electromagnetic field intensity and a frequency range of 10 Hz to 100 kHz, a frequency stability of ≤ ±1×10 -6 、amplitude accuracy of ≤ ±0.05%, and an electromagnetic field intensity within 0.1 mT to 1 T before use. During calibration, measure 3 to 5 times at each calibration point and take the average value. Set the sensitivity error within ±1%, the linearity error within ±0.5%, and the repeatability error within ±0.2%. If the measured value is within the range, it indicates that the calibration is successful. If it exceeds the range, check for coil aging and loose connections, and re-calibrate after repair.

[0020] As a preferred technical solution of the present invention, the measurement positions described in step three are selected according to the IGBT chip electromagnetic field model established in step one. Select the best electromagnetic field measurement points according to the recorded electromagnetic field distribution of the IGBT chip electromagnetic field model. At the same time, when selecting the measurement positions, three measurement points need to be arranged, and the consistency of the results is ensured by comparing the measurement results of the three measurement points.

[0021] As a preferred technical solution of the present invention, the specific method for measuring the change of the electromagnetic field in step four is as follows: First, perform static field measurement: Apply a static voltage to the IGBT chip, and after measurement by the measuring device, record the electric field strength; then perform dynamic field measurement: Record the switching transient magnetic field waveform through the measuring device, and finally obtain multiple sets of change data of the electromagnetic field around the IGBT chip during operation.

[0022] As a preferred technical solution of the present invention, before starting the test of measuring the change of the electromagnetic field in step four, it is necessary to measure the electromagnetic background noise of the test environment when the IGBT chip is not working, as the reference for subsequent measurement. When performing subsequent calculations, subtract the measured data from the electromagnetic background noise to obtain the measurement data without interference from the test environment.

[0023] As a preferred technical solution of the present invention, the relationship between the electromagnetic field and the operating parameters of the IGBT chip in step five is obtained through simulation analysis of the IGBT chip electromagnetic field model in step one. Through simulation analysis, the collector current of the IGBT chip in the relationship model is expressed as:

[0024] lc = a * H + b

[0025] Where lc is the IGBT collector current, H is the peak value of the electromagnetic field strength of the IGBT chip, and a and b are constant values obtained through simulation. By calculating the fitting linear coefficients of multiple sets of simulation data, the values of a and b can be obtained.

[0026] As a preferred technical solution of the present invention, the switching voltage of the IGBT chip in the relationship model is expressed as:

[0027] Vce = d * H + e

[0028] Where Vce represents the switching voltage of the IGBT chip, H is the peak value of the electromagnetic field strength of the IGBT chip, and d and e are constant values obtained through simulation. By calculating the fitting linear coefficients of multiple sets of simulation data, the values of d and e can be obtained.

[0029] As a preferred technical solution of the present invention, the specific method for the operating parameters of the IGBT chip in step six is as follows: Select the electromagnetic field parameters related to the relationship model from the measurement data, remove the high-frequency noise with a low-pass filter, and then extract the peak value. The cut-off frequency of the low-pass filter is set according to the operating frequency of the IGBT.

[0030]

[0031] Where f c is the cut-off frequency of the low-pass filter, and f IGBT is twice the operating frequency of the IGBT chip.

[0032] Then, the extracted peak data is normalized, and the extracted peak data is mapped to [0, 1] to eliminate the dimension difference and improve the model training efficiency. The specific method is Min - Max normalization.

[0033]

[0034] Among them, X min is the minimum value of the data, and X max is the maximum value of the data. For each data point X i , calculate the normalized value X norm , where b is 1 and a is 0.

[0035] After removing the maximum and minimum values, calculate the average value of the peak data. Finally, substitute the processed peak data into the relationship model for calculation to obtain the key operating parameters of the IGBT chip.

[0036] The beneficial effects of the present invention are as follows:

[0037] By establishing an electromagnetic field model of the IGBT chip, the present invention realizes non - contact electromagnetic measurement of the IGBT chip, avoiding possible damage or interference caused by physical contact. By continuously monitoring the electromagnetic field changes during the normal operation of the IGBT chip in real time, the operating parameters can be indirectly obtained. Furthermore, it can detect weak electromagnetic field changes during the switching transient process and convert them into accurate electrical signals, and can cover a wide frequency range from low frequency to high frequency of the IGBT chip, meeting the measurement requirements of the IGBT chip under different working conditions. Compared with traditional contact measurement methods, it is more suitable for the development needs of IGBT chips. Description of the Drawings

[0038] Figure 1 is the flow chart of the present invention:

[0039] Figure 2 is the comparison measurement table of key parameters in the on / off state of the present invention;

[0040] Figure 3 is the measurement comparison table before and after H peak noise deduction of the present invention;

[0041] Figure 4 is the measurement comparison table before and after Vce noise deduction of the present invention. Detailed Embodiments

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] As Figure 1 shown, the embodiment of the present invention provides a non-contact working parameter measurement method for an IGBT chip, and the specific steps are as follows:

[0044] Step 1: Establish a simulation model

[0045] Use modeling software to establish an electromagnetic field model of the IGBT chip, and then, according to the established electromagnetic field model of the IGBT chip, simulate the electromagnetic field distribution under different working conditions and record it;

[0046] Step 2: Prepare the test environment

[0047] Select a suitable test site and measurement equipment, and then arrange the test platform and fix the IGBT chip on the test platform;

[0048] Step 3: Determine the measurement position

[0049] Select a suitable measurement position around the IGBT chip and place the measurement equipment prepared in Step 2;

[0050] Step 4: Measure the change in the electromagnetic field

[0051] Use the measurement equipment to measure the change in the electromagnetic field around the IGBT chip during operation. According to Faraday's law of electromagnetic induction, when a coil is in a changing magnetic field, an induced electromotive force will be generated in the coil. By measuring the induced electromotive force, the change rate of the magnetic field can be calculated, and then the magnetic field strength can be obtained;

[0052] Step 5: Establish the relationship between the electromagnetic field and the working parameters of the IGBT chip

[0053] Based on the electromagnetic field theory, analyze the relationship between the change in the electromagnetic field and the voltage and current working parameters of the IGBT chip during operation;

[0054] Step 6: Calculate the working parameters of the IGBT chip

[0055] Calculate the working parameters of the IGBT chip according to the relationship between the electromagnetic field and the working parameters of the IGBT chip established in Step 5.

[0056] Through the simulation of the IGBT chip in Step 1, the electromagnetic field model of the IGBT chip can be obtained. After preparing the test environment, the electromagnetic field distribution of the IGBT chip under different working conditions can be simulated according to the established electromagnetic field model of the IGBT chip, so as to provide data support for the determination of the measurement position. Finally, according to the measured electromagnetic field change, the specific value can be calculated according to the established relationship between the electromagnetic field and the working parameters of the IGBT chip, thus realizing the non-contact electromagnetic method measurement of the working parameters of the IGBT chip.

[0057] Among them, the modeling software in Step 1 uses COMSOL Multiphysics. When modeling, the pre-drawn CAD file of the IGBT chip is imported to create the geometric model of the IGBT chip. When performing static electric field analysis, the mesh division is set to 0.1μm in the gate region and 10μm in other regions; the boundary conditions are set to anode / cathode ohmic contact and gate voltage excitation; the solver is the MUMPS direct solver; when performing transient switching characteristic analysis, the mesh division is set to 0.5μm in the channel region and 5μm in other regions; the boundary conditions are set to anode pulse voltage, cathode grounded, and gate drive signal; the solver is BDF time stepping + GMRES iteration. After the geometric model of the IGBT chip is created, select the electromagnetic field module in COMSOL Multiphysics to analyze and establish the electromagnetic field model of the IGBT chip. Finally, simulate and record the electromagnetic field distributions under the two different working conditions of conduction and turn-off. After the simulation is completed, use the measurement device in Step 2 to actually measure the electromagnetic field intensity under the same simulation conditions, and then compare the measured value with the simulation result to verify the model accuracy. If the results are consistent, it means that the electromagnetic field model of the IGBT chip is successfully established, and the electromagnetic field model of the IGBT chip is verified to be qualified. If the results are inconsistent, repeat the operation in Step 1 to re-model.

[0058] COMSOL Multiphysics is a powerful multi-physics simulation software that provides multiple physical field modules such as structural mechanics, fluid flow, heat transfer, electromagnetic field, acoustics, and chemical reactions, and can handle the interactions between multiple physical fields. Users can select appropriate modules for simulation according to their needs. In addition, COMSOL Multiphysics has built-in various solvers that can meet the solution requirements of different types of problems.

[0059] Among them, the test site in step two is selected as an electromagnetic shielding room. The measuring equipment in step two includes a detection coil, a spectrum analyzer, an oscilloscope, and a low-pass filter. The spectrum analyzer sets the measurement frequency range according to the operating frequency of the IGBT chip before use. The oscilloscope sets the sampling rate according to the measurement needs before use. Before use, the detection coil is calibrated with a standard source whose known electromagnetic field strength and frequency range are from 10 Hz to 100 kHz, the frequency stability is ≤ ±1×10 -6 -6 , the amplitude accuracy is ≤ ±0.05%, and the electromagnetic field strength is within 0.1 mT to 1 T. During calibration, each calibration point is measured 3 to 5 times, and the average value is taken. The sensitivity error is set within ±1%, the linearity error is within ±0.5%, and the repeatability error is within ±0.2%. If the measured value is within the range, it indicates that the calibration is successful. If it exceeds the range, the coil aging and loose connection are checked, and after repair, the calibration is performed again.

[0060] When selecting an electromagnetic shielding room, it is necessary to ensure that the test site is far away from equipment such as high-voltage wires, high-power motors, and radio transmissions to prevent electromagnetic interference. At the same time, when using measuring equipment such as detection coils, spectrum analyzers, and oscilloscopes, all test equipment needs to be grounded to reduce ground loop interference. At the same time, the grounding wire should use a low-impedance wire to ensure good grounding. The coil diameter of the detection coil is 0.5 mm, and the material is a non-magnetic coil wound with copper Litz wire. The number of turns is 50 turns. The model of the spectrum analyzer selected is Tektronix RSA5100A, and the parameter settings are: RBW: 100 kHz; VBW: 10 kHz; Span: 1 GHz; Center Frequency: 5 GHz. The model of the oscilloscope selected is Keysight DSOX92004A: bandwidth 2 GHz, 4 channels, sampling rate 20 GSa / s.

[0061] Among them, the measurement position in step three is selected according to the IGBT chip electromagnetic field model established in step one. The best electromagnetic field measurement points are selected according to the electromagnetic field distribution of the recorded IGBT chip electromagnetic field model. At the same time, when selecting the measurement position, three measurement points need to be arranged, and the consistency of the results is ensured by comparing the measurement results of the three measurement points.

[0062] Through the simulation of the IGBT chip electromagnetic field model under different operating conditions, the magnetic field strength at the upper left corner of the IGBT chip is the largest at the moment of turn-off. Therefore, the detection coil is preferably arranged at this position. At the same time, after the measurement position is selected, verification and adjustment are required to prevent the signal from being too weak or the interference from being too large at a certain position.

[0063] Among them, the specific method for measuring the electromagnetic field change in Step 4 is as follows: First, perform static field measurement: Apply a static voltage to the IGBT chip, and after measurement by the measuring device, record the electric field strength; then perform dynamic field measurement: Record the switching transient magnetic field waveform through the measuring device, and finally obtain multiple sets of data on the electromagnetic field change around the IGBT chip during operation.

[0064] When obtaining the measurement data, it is necessary to use a low-pass filter to remove low-frequency drift and high-frequency noise, and then compare it with the standard source to ensure that the linearity error is less than one percent. At the same time, take the average value of the measurement data at three measurement points to ensure the consistency of the comparison results.

[0065] Among them, before starting the test of measuring the electromagnetic field change in Step 4, it is necessary to measure the electromagnetic background noise of the test environment when the IGBT chip is not working, which serves as the benchmark for subsequent measurements. When performing subsequent calculations, subtract the measured data from the electromagnetic background noise to obtain the measurement data without interference from the test environment.

[0066] By recording the spectral characteristics of the background noise, it is convenient to subtract the noise influence from the measurement results, thereby improving the accuracy of the calculation results.

[0067] Among them, the relationship between the electromagnetic field and the operating parameters of the IGBT chip in Step 5 is obtained through simulation analysis of the IGBT chip electromagnetic field model in Step 1. Through simulation analysis, the collector current of the IGBT chip in the relationship model is expressed as:

[0068] lc = a * H + b

[0069] Among them, lc is the IGBT collector current, H is the peak value of the electromagnetic field strength of the IGBT chip, and a and b are constant values obtained from the simulation.

[0070] The values of a and b are obtained through the solver built in COMSOL Multiphysics. By performing multiple simulations of the IGBT chip electromagnetic field model, the specific values of a and b can be obtained. By calculating the fitting linear coefficients of multiple sets of simulation data, the values of a and b can be obtained.

[0071] Among them, the switching voltage of the IGBT chip in the relationship model is expressed as:

[0072] Vce = d * H + e

[0073] Among them, Vce represents the switching voltage of the IGBT chip, H is the peak value of the electromagnetic field strength of the IGBT chip, and d and e are constant values obtained from the simulation. By calculating the fitting linear coefficients of multiple sets of simulation data, the values of d and e can be obtained.

[0074] The switching voltage of the IGBT chip involves the gate-emitter voltage, which is a key parameter for controlling the conduction and cutoff of the IGBT. When a positive voltage is applied between the gate and the emitter and this voltage is higher than the threshold voltage, the IGBT enters the conduction state. When a negative gate voltage is applied, the IGBT will turn off.

[0075] Among them, the specific method for the IGBT chip operating parameters in step six is as follows: Select the electromagnetic field parameters related to the relationship model from the measurement data, remove the high-frequency noise with a low-pass filter, and then extract the peak value. The cut-off frequency of the low-pass filter is set according to the operating frequency of the IGBT.

[0076]

[0077] Among them, f c is the cut-off frequency of the low-pass filter, and f IGBT is twice the operating frequency of the IGBT chip.

[0078] Then, normalize the extracted peak value data, map the extracted peak value data to [0, 1] to eliminate the dimension difference and improve the model training efficiency. The specific method is Min-Max normalization.

[0079]

[0080] Among them, X min is the minimum value of the data, X max is the maximum value of the data. For each data point X i , calculate the normalized value X norm , where b is 1 and a is 0.

[0081] After removing the maximum and minimum values, calculate the average value of the peak value data. Finally, substitute the processed peak value data into the relationship model for calculation to obtain the key operating parameters of the IGBT chip.

[0082] When calculating the IGBT chip operating parameters, it is necessary to ensure that the unit of lc is A, the unit of H is T, and the unit of Vce is V. At the same time, it is also necessary to re-calibrate the coefficients a, b and d, e according to the change of the IGBT operating conditions to ensure the dynamic calibration relationship model.

[0083] As Figure 2 shown, Figure 2 is the key parameter measurement comparison table of the IGBT chip of model Infineon IKW40N120T2 (1200V / 40A). The measurement conditions are: bus voltage 600V, load inductance 100μH, and the calculation formula is: Among them, t rise = 50ns, I c = 20A;

[0084] As Figure 3 and Figure 4 shown Figure 3 and Figure 4 are the data comparisons before and after background noise deduction, indicating that after noise deduction, the electromagnetic method for measuring the key parameters of IGBTs in the present invention has a high degree of coincidence with the traditional measurement method.

[0085] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0086] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A non-contact working parameter measurement method for IGBT chips, characterized in that, The specific steps are as follows: Step 1: Establish a simulation model Use modeling software to establish the electromagnetic field model of the IGBT chip, and then, based on the established electromagnetic field model of the IGBT chip, simulate the electromagnetic field distribution under different working conditions and record it; Step 2: Prepare the test environment Select a suitable test site and measurement equipment, then arrange the test platform and fix the IGBT chip on the test platform; Step 3: Determine the measurement positions Select suitable measurement positions around the IGBT chip and place the measurement equipment prepared in Step 2; Step 4: Measure the change in the electromagnetic field Use the measurement equipment to measure the change in the electromagnetic field around the IGBT chip during operation. According to Faraday's law of electromagnetic induction, when a coil is in a changing magnetic field, an induced electromotive force will be generated in the coil. By measuring the induced electromotive force, the rate of change of the magnetic field can be calculated, and then the magnetic field strength can be obtained; Step 5: Establish the relationship between the electromagnetic field and the operating parameters of the IGBT chip Based on electromagnetic field theory, analyze the relationship between the change in the electromagnetic field and the voltage and current operating parameters of the IGBT chip during operation; Step 6: Calculate the operating parameters of the IGBT chip Calculate the operating parameters of the IGBT chip according to the relationship between the electromagnetic field and the operating parameters of the IGBT chip established in Step 5.

2. The non-contact working parameter measurement method for IGBT chips according to claim 1, wherein: The modeling software mentioned in Step 1 uses COMSOL Multiphysics. When modeling, import the pre-drawn CAD file of the IGBT chip to create the geometric model of the IGBT chip. In the static electric field analysis, the mesh size is set to 0.1 μm in the gate region and 10 μm in other regions; the boundary conditions are set as Ohmic contacts at the anode / cathode and gate voltage excitation; the solver is the MUMPS direct solver; in the transient switching characteristic analysis, the mesh size is set to 0.5 μm in the channel region and 5 μm in other regions; the boundary conditions are set as anode pulse voltage, cathode grounded, and gate drive signal; the solver is BDF time stepping + GMRES iteration. After the geometric model of the IGBT chip is created, select the electromagnetic field module in COMSOL Multiphysics to analyze and establish the electromagnetic field model of the IGBT chip. Finally, simulate and record the electromagnetic field distributions under the two different working conditions of conduction and turn-off. After the simulation is completed, use the measurement equipment in Step 2 to actually measure the electromagnetic field strength under the same simulation conditions, and then compare the measured values with the simulation results to verify the model accuracy. If the results are consistent, it means that the electromagnetic field model of the IGBT chip is successfully established, and the electromagnetic field model of the IGBT chip is verified to be qualified. If the results are inconsistent, repeat the operation in Step 1 to re-model.

3. A non-contact working parameter measurement method for IGBT chips according to claim 1, characterized in that: In Step 2, the test site is selected as an electromagnetic shielding room. The measuring equipment in Step 2 includes a detection coil, a spectrum analyzer, an oscilloscope, and a low-pass filter. Before use, the spectrum analyzer sets the measurement frequency range according to the operating frequency of the IGBT chip. Before use, the oscilloscope sets the sampling rate according to the measurement requirements. Before use, the detection coil is calibrated with a standard source with a known electromagnetic field strength, a frequency range of 10 Hz to 100 kHz, a frequency stability of ≤ ±1×10 -6 , an amplitude accuracy of ≤ ±0.05%, and an electromagnetic field strength within 0.1 mT to 1 T. During calibration, each calibration point is measured 3 to 5 times, and the average value is taken. The sensitivity error is set within ±1%, the linearity error is within ±0.5%, and the repeatability error is within ±0.2%. If the measured value is within the range, it indicates that the calibration is successful. If it exceeds the range, check for coil aging and loose connections, and after repair, perform the calibration again.

4. A non-contact working parameter measurement method for an IGBT chip according to claim 1, characterized in that: The measurement positions mentioned in Step 3 are selected according to the electromagnetic field model of the IGBT chip established in Step 1. Select the best measurement points for the electromagnetic field according to the recorded electromagnetic field distribution of the electromagnetic field model of the IGBT chip. At the same time, when selecting the measurement positions, three measurement points need to be arranged, and the consistency of the results is ensured by comparing the measurement results of the three measurement points.

5. A non-contact working parameter measurement method for IGBT chips according to claim 1, characterized in that: The specific method for measuring the electromagnetic field change described in Step 4 is as follows: First, perform static field measurement: Apply a static voltage to the IGBT chip, and after measurement by the measuring device, record the electric field strength. Then, perform dynamic field measurement: Record the switching transient magnetic field waveform through the measuring device. Finally, obtain multiple sets of data on the change of the electromagnetic field around the IGBT chip during operation.

6. A non-contact working parameter measurement method for an IGBT chip according to claim 1, characterized in that: Before starting the test of measuring the electromagnetic field change described in Step 4, it is necessary to measure the electromagnetic background noise of the test environment when the IGBT chip is not operating, which serves as the benchmark for subsequent measurements. When performing subsequent calculations, subtract the measured data from the electromagnetic background noise to obtain the measurement data without interference from the test environment.

7. A non-contact working parameter measurement method for IGBT chips according to claim 1, characterized in that: The relationship between the electromagnetic field and the operating parameters of the IGBT chip described in Step 5 is obtained through simulation analysis of the IGBT chip electromagnetic field model in Step 1. Through simulation analysis, the collector current of the IGBT chip in the relationship model is expressed as: lc = a*H + b where lc is the IGBT collector current, H is the peak value of the electromagnetic field strength of the IGBT chip, and a and b are constant values obtained from the simulation. By calculating the fitting linear coefficients of multiple sets of simulation data, the values of a and b can be obtained.

8. A non-contact working parameter measurement method for IGBT chips according to claim 7, characterized in that: The switching voltage of the IGBT chip in the relationship model is expressed as: Vce = d*H + e where Vce represents the switching voltage of the IGBT chip, H is the peak value of the electromagnetic field strength of the IGBT chip, and d and e are constant values obtained from the simulation. By calculating the fitting linear coefficients of multiple sets of simulation data, the values of d and e can be obtained.

9. A non-contact working parameter measurement method for an IGBT chip according to claim 1, characterized in that: The specific method for the operating parameters of the IGBT chip described in Step 6 is as follows: Select the electromagnetic field parameters related to the relationship model from the measurement data, remove the high-frequency noise using a low-pass filter, and then extract the peak value. The cut-off frequency of the low-pass filter is set according to the operating frequency of the IGBT. where f c is the cut-off frequency of the low-pass filter, and f IGBT is twice the operating frequency of the IGBT chip Then, perform normalization processing on the extracted peak value data, map the extracted peak value data to [0, 1] to eliminate the dimension difference and improve the model training efficiency. The specific method is Min-Max normalization. Among them, X min is the minimum value of the data, and X max is the maximum value of the data. For each data point X i , calculate the normalized value X norm , where b is 1 and a is 0; After removing the maximum and minimum values, calculate the average value of the peak value data. Finally, substitute the processed peak value data into the relationship model for calculation to obtain the key operating parameters of the IGBT chip.

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