A power module dynamic switching parameter calculation method

Abstract

A kind of power module dynamic switch parameter calculation method, comprising: using dynamic double-pulse test waveform to power module, the center point position of each pulse is calculated out;Waveform data of gate voltage waveform Vge, current waveform Ic and bus voltage waveform Vce are respectively carried out zero drift processing;According to the three waveform data obtained after eliminating zero drift, the basic parameters Vge- Pos 、Vge‑ Neg 、U dc 、I CM , first pulse turn-off Turn- off And the waveform data of second pulse turn-on Turn- on Time period in double pulse are respectively obtained, and the turn-off and turn-on process parameters are calculated, and the starting value and end value of each corresponding parameter are calculated according to the percentage of each parameter in turn-off and turn-on process, and finally the corresponding parameters are obtained.The present application does not need to use filter, and is realized based on software algorithm, which can ensure that the test data fluctuation is not too large due to waveform oscillation or waveform difference, and can make the test result close to the actual value, so as to ensure the authenticity of data.

Description

Technical Field

[0001] This invention relates to the field of power module testing and calculation, and specifically to a method for calculating dynamic switching parameters of a power module. Background Technology

[0002] Typically, semiconductor power devices undergo avalanche, static, and dynamic tests upon completion of manufacturing to ensure a high product yield. Currently, some small factories in China only perform avalanche and static tests, neglecting dynamic testing. Larger factories, while conducting dynamic testing, primarily use imported equipment, with limited domestic options and high costs. Dynamic testing mainly measures the limits, performance parameters, and product consistency of power devices during switching. It not only assesses the product yield and ensures reliability but also provides engineers with insights for further product analysis and future upgrades. Due to hardware and environmental factors, the actual sampled waveform data may exhibit oscillations, zero drift, and ripple interference, affecting the test results. The traditional approach is to increase filtering to remove oscillating waveforms and smooth them out; however, this approach generally presents several problems.

[0003] First, the filtering coefficients in the program are fixed. If the consistency between different devices is poor and the oscillation ratio is large, the fixed filtering coefficients may not be able to smooth the waveform. The waveforms will be quite different, and the test results of different devices will vary greatly.

[0004] Secondly, the position of each oscillation on the same device may be slightly off. If the filtering coefficient is too small, the oscillation may not be completely filtered out, resulting in the calculated value being either before or after the oscillation. This leads to large fluctuations in the final test results and significant deviations in the test data for the same device.

[0005] Secondly, if the filter coefficient is too large, it will cause waveform distortion, and the test results will differ significantly from the actual values, thus losing the authenticity of the test and rendering the test data unreliable for product performance and defect analysis. Summary of the Invention

[0006] Based on this, the present invention provides a method for calculating dynamic switching parameters of power modules to solve the technical problem that the existing dynamic testing methods for power devices are not reasonable enough, the test results differ greatly from the actual values, lose the authenticity of the test, and cause the test results data to lose reference value for product performance and defect analysis.

[0007] To achieve the above objectives, the present invention provides a method for calculating dynamic switching parameters of a power module, comprising the following steps:

[0008] S1. The power module is tested using a dynamic double-pulse test waveform, which consists of a gate voltage waveform Vge, a current waveform Ic, and a bus voltage waveform Vce. The three waveform data are obtained: gate voltage waveform Vge, current waveform Ic, and bus voltage waveform Vce. The center point position of each pulse is calculated.

[0009] S2. Perform zero-drift processing on the waveform data of gate voltage waveform Vge, current waveform Ic and bus voltage waveform Vce respectively.

[0010] S3. Based on the three waveform data obtained after eliminating zero drift, calculate the basic parameters Vge-Pos, Vge-Neg, Udc, and ICM. Then, obtain the waveform data of the first pulse turn-off and the second pulse turn-on time periods in the dual pulse, and calculate the turn-off and turn-on process parameters respectively. Based on the percentage of each parameter during the turn-off and turn-on processes, calculate the value of each corresponding parameter, and finally obtain the dynamic switching parameters of the power module.

[0011] As a further preferred embodiment of the present invention, the calculation of the center point position of each pulse in step S1 specifically includes:

[0012] Calculate the temporary value U1 of the bus voltage waveform Vce. U1 is the average value of the first 50 points of the Vce waveform data. Calculate U60% and U40% based on U1. U60% = 60% × U1, U40% = 40% × U1.

[0013] The system iteratively compares the current voltage value Ud of Vce. When Ud is less than or equal to U40%, the current voltage value V1 is recorded. The comparison continues, and when Ud is greater than or equal to U60%, the current voltage value V2 is recorded. The comparison continues, and when Ud is less than or equal to U40%, the current voltage value V3 is recorded. The comparison continues, and when Ud is greater than or equal to U60%, the current voltage value V4 is recorded.

[0014] Based on the recorded V1, V2, V3, V4, calculate the midpoints T1, T2, T3, T4, and T5 of the lines 0-V1, V1-V2, V2-V3, V3-V4, and V4-end. Then calculate the midpoints T1-1, T2-1, T3-1, T4-1, and T5-1 of the lines T1-V1, T2-V2, T3-V3, T4-V4, and T5-end.

[0015] As a further preferred embodiment of the present invention, step S2 involves zero-drift processing of the waveform data, specifically including:

[0016] Process the waveform:

[0017] Calculate the average values ​​of Vge from T1 to T1-1, Vge from T2 to T2-1, Vce from T2 to T2-1, and Ic from T1 to T1-1 respectively: VgeT1-T1-1, VgeT2-T2-1, VceT2-T2-1, and IcT1-T1-1.

[0018] Eliminate zero drift:

[0019] Vge zero-drift processing involves calculating the offset Vd of Vge based on the known positive input gate voltage Vge+ and negative gate voltage Vge-. The calculation formula is as follows:

[0020] Vd=(Vge+ - VgeT2-T2-1)-((Vge+ - Vge-)-(VgeT2-T2-1 -VgeT1-T1-1)) / 2

[0021] Then add the offset Vd to all the waveform data of Vge to get the new waveform data Vge-new;

[0022] Vce zero drift processing involves subtracting the offset VceT2-T2-1 from all Vce waveform data to obtain new Vce waveform data (Vce-new).

[0023] Ic zero-drift processing involves subtracting the offset IcT1-T1-1 from all Ic waveform data to obtain new Ic waveform data (Ic-new).

[0024] As a further preferred technical solution of the present invention, in step S3, based on the three waveform data obtained after eliminating zero drift, the basic parameters Vge-Pos, Vge-Neg, Udc, and ICM are calculated, specifically including:

[0025] Calculate the average values ​​of Vge-new from T1 to T1-1, Vge-new from T2 to T2-1, and Vce-new from T2 to T2-1 respectively to obtain Vge-Pos, Vge-Neg, and Udc;

[0026] Calculate the maximum value of Ic from T2 to T3 to obtain ICM.

[0027] As a further preferred technical solution of the present invention, step S3, acquiring the waveform of the first pulse turn-off process and calculating the turn-off process parameters, specifically includes:

[0028] Take the waveform data of the T2-T3 section, starting from time T2 and ending at time T3, as the waveform of the turn-off process;

[0029] Obtain the total number of waveform data from T2 to T3, and use this as the loop count to iterate. Sequentially obtain the current values ​​of the waveform data for Vge-new, Vce-new, and Ic-new, and then perform data processing calculations. During the shutdown process, each parameter is calculated as follows:

[0030] The process iteratively checks whether the current voltage value Vge is less than or equal to 90% of Vge-Pos, and takes the time ToffS for that moment. It then iteratively checks whether the current value Ic is greater than or equal to ICM. From that moment, it checks whether the current value Ic is less than or equal to 10% of ICM, taking the time Ttem for that moment. This process is repeated until time T3. The time ToffE at time Ttem is then calculated as the turn-off time using the following formula:

[0031] Toff = ToffE – ToffS;

[0032] The system iteratively checks whether the current voltage value (Vge - Pos) is less than or equal to 90% of Vge - Pos, and takes the time TdoffS for that moment. It then iteratively checks whether the current value (Ic - ICM) is greater than or equal to ICM, and from that moment onwards checks whether the current value (Ic - ICM) is less than or equal to 90% of ICM, taking the time TdoffE for that moment. The time difference between TdoffE and TdoffS is calculated as the turn-off delay time using the following formula:

[0033] Tdoff = TdoffE – TdoffS;

[0034] The process iteratively checks whether the current value at the new current moment (Ic) is greater than or equal to ICM. From that moment, it checks whether the current value at the new current moment (Ic) is less than or equal to 90% of ICM, taking the time Tf-offS. From that moment, it checks whether the current value at the new current moment (Ic) is less than or equal to 10% of ICM, taking the time Ttem. It then checks whether the current value at the new current moment (Ic) is greater than or equal to 10% of ICM. If so, the time Ttem is reset to zero, and the process repeats until the end at time T3. The time Tf-offE at time Ttem is then calculated. The time difference between Tf-offE and Tf-offS is calculated as the turn-off current fall time using the following formula:

[0035] Tf-off = Tf-offE - Tf-offS;

[0036] The loop iterates through the current values, checking whether the current value at the current instant (Ic - the new current instant) is greater than or equal to ICM. From that instant, it checks whether the current value at the current instant (Ic - the new current instant) is less than or equal to 90% of ICM, taking the current value IdidtS-off and the current time TdidtS-off. Then, it checks whether the current value at the current instant (Ic - the new current instant) is less than or equal to 50% of ICM, taking the current value IdidtE-off and the current time TdidtE-off. If a later value is larger than an earlier value during the transition from 90% ICM to 50% ICM, the loop exits. The current value IdidtE-off and the current time TdidtE-off are then taken. The slope from TdidtS-off to TdidtE-off is calculated as the rate of change of the turn-off current using the following formula:

[0037] di / dt-off = (IdidtE-off - IdidtS-off) / (TdidtE-off - TdidtS-off));

[0038] The algorithm iteratively checks whether the current voltage value at time Vce is greater than or equal to 10% of Udc, taking the time Tr-offS for that moment. It then checks whether the current voltage value at time Vce is greater than or equal to 90% of Udc, taking the time Ttem for that moment. Next, it checks whether the current voltage value at time Vce is less than or equal to 90% of Udc. If so, the time Ttem is reset to zero, and the algorithm repeats the process until time T3 ends. The time Tr-offE at time Ttem is then calculated. The time difference between Tr-offE and Tr-offS is calculated as the turn-off voltage rise time using the following formula:

[0039] Tr-off = Tr-offE - Tr-offS;

[0040] The loop iterates through the following steps: It checks if the current voltage value (Vce) is greater than or equal to 50% of Udc, taking the voltage value at that moment (UdvdtS-off) and the current time (TdvdtS-off). From that moment on, it continues to check if the current voltage value (Vce) is greater than or equal to 70% of Udc, taking the voltage value at that moment (UdvdtE-off) and the current time (TdvdtE-off). If, during the transition from 50% Udc to 70% Udc, a later value is smaller than an earlier value, the loop exits. The current voltage value (UdvdtE-off) and the current time (TdvdtE-off) are then taken. The slope from TdvdtS-off to TdvdtE-off is calculated using the following formula as the rate of change of the turn-off voltage:

[0041] dv / dt-off = (UdvdtE-off - UdvdtS-off) / (TdvdtE-off - TdvdtS-off);

[0042] The process iteratively checks whether the current voltage value of Vce-new is greater than or equal to 10% of Udc, and takes the time TEoffS for that moment. It then iteratively checks whether the current value of Ic-new is greater than or equal to ICM. From that moment, it checks whether the current value of Ic-new is less than or equal to 10% of ICM, taking the time Ttem for that moment. This process is repeated until time T3, at which point the time TEoffE is taken. The integral of the product of Vce-new and Ic-new during the time interval from TEoffS to TEoffE is the turn-off loss, calculated using the following formula: ;

[0043] The system iteratively compares the current voltage value Vce with the temporary voltage value Vtem, storing the larger value in the temporary voltage value Vtem. This process continues until the loop ends, at which point the voltage value Vtem is retrieved as the maximum turn-off peak voltage Vce-PK.

[0044] As a further preferred technical solution of the present invention, in step S3, the waveform of the second pulse turn-on process is obtained, and the turn-on process parameters are calculated, specifically including:

[0045] Take the waveform data from T3 to T4, starting from time T3 and ending at time T4, which is the waveform of the start-up process;

[0046] Obtain the total number of waveform data points from T3 to T4, and use this as the loop count to iterate. Sequentially obtain the current values ​​of the Vge-new, Vce-new, and Ic-new waveform data, and then perform data processing calculations. During the activation process, each parameter is calculated as follows:

[0047] The process iteratively checks whether the current voltage value (Vge - Pos) is greater than or equal to 10% of Vge - Pos, and takes the time TonS for that moment. It then checks whether the current value (Ic - Ic) is greater than or equal to 90% of ICM, and takes the time Ttem for that moment. This process is repeated until time T4, at which point the time TonE is taken. The difference between TonE and TonS is calculated using the following formula as the turn-on time:

[0048] Ton = TonE - TonS;

[0049] The system iteratively checks whether the current voltage value (Vge) is greater than or equal to 10% of Vge - Pos, and takes the time TdonS at that moment. It also iteratively checks whether the current current value (Ic) is greater than or equal to 10% of ICM, and takes the time TdonE at that moment. The time difference between TdonE and TdonS is calculated using the following formula as the turn-on delay time:

[0050] Tdon = TdonE – TdonS;

[0051] The process iteratively checks whether the current value at the current instant Ic is greater than or equal to 10% of ICM, taking the time Tr-onS for that instant. From that instant, it checks whether the current value at the current instant Ic is greater than or equal to 90% of ICM, taking the time Ttem for that instant. Then it checks whether the current value at the current instant Ic is less than or equal to 90% of ICM. If so, the time Ttem is reset to zero, and the process is repeated until the end of the cycle at time T4. The time Tr-onE for Ttem is then calculated. The time difference between Tr-onE and Tr-onS is calculated as the turn-on current rise time using the following formula:

[0052] Tr-on = Tr-onE - Tr-onS;

[0053] The loop iterates through the current values, checking whether the current value at the current instant (Ic - the new current value) is greater than or equal to 50% of the ICM. It takes the current value IdidtS-on at that instant and the current time TdidtS-on. From that instant, it continues to check whether the current value at the current instant (Ic - the new current value) is greater than or equal to 90% of the ICM, taking the current value IdidtE-on at that instant and the current time TdidtE-on. If, during the transition from 50% to 90% of the ICM, a later value is smaller than an earlier value, the loop exits, and the current current value IdidtE-on and the current time TdidtE-on are retrieved. The slope from TdidtS-on to TdidtE-on is calculated as the rate of change of the turn-on current.

[0054] di / dt-on = (IdidtE-on - IdidtS-on) / (TdidtE-on - TdidtS-on);

[0055] The process iteratively checks whether the current voltage value of Vce is less than or equal to 90% of Udc, taking the time Tf-onS. It then checks whether the current voltage value of Vce is less than or equal to 10% of Udc, taking the time Ttem. This process is repeated until time T4. The time Tf-onE is then taken, and the time difference between Tf-onE and Tf-onS is calculated as the turn-on voltage drop time using the following formula:

[0056] Tf-on = Tf-onE - Tf-onS;

[0057] The loop iterates through the current voltage value (Vce) to determine if it is less than or equal to 70% of Udc. It then takes the voltage value UdvdtS-on at that moment and the current time TdvdtS-on. From that moment on, it continues to determine if the current voltage value (Vce) is less than or equal to 50% of Udc. It takes the voltage value UdvdtE-on at that moment and the current time TdvdtE-on. If, during the transition from 70% Udc to 50% Udc, a later value is greater than an earlier value, the loop exits. The loop then takes the current voltage value UdvdtE-on and the current time TdvdtE-on, and calculates the slope from TdvdtS-on to TdvdtE-on as the rate of change of the turn-on voltage using the following formula:

[0058] dv / dt-on = (UdvdtE-on - UdvdtS-on) / (TdvdtE-on - TdvdtS-on);

[0059] The process iteratively checks whether the current value of Ic-new at the current moment is greater than or equal to 10% of ICM, and takes the time TEonS for that moment. Iteratively checks whether the current voltage value of Vce-new at the current moment is less than or equal to 10% of Udc, and takes the time Ttem for that moment. This process is repeated until time T4, at which point the time TEonE is taken. The integral of the product of Ic-new and Vce-new during the time interval from TEonS to TEonE is then calculated as the open-circuit loss: ;

[0060] The process iteratively checks whether the current value of Ic-new at the current moment is greater than or equal to 10% of ICM, and takes the time TIc-pkS for that moment. Iteratively checks whether the voltage value of Vce-new at the current moment is less than or equal to 2% of Udc, and takes the time Ttem for that moment. It then continues to check whether the voltage value of Vce-new at the current moment is greater than or equal to 2% of Udc. If it is, the time value Ttem is cleared to zero, and the process continues to check whether the voltage value of Vce-new at the current moment is less than or equal to 2% of Udc, and takes the time Ttem for that moment. This process is repeated until the end of time T4. The time Ttem is then taken as TIc-pkE. The maximum peak current of Ic-new during the time period from TIc-pkS to TIc-pkE is calculated as the turn-on peak current Ic-PK.

[0061] The dynamic switching parameter calculation method for power modules proposed in this invention does not require filtering and is entirely based on software algorithms. This ensures that the test data will not fluctuate significantly due to waveform oscillations or differences, and also makes the test results close to the actual values, thereby ensuring the authenticity of the data.

[0062] By adopting the above technical solution, the present invention can also achieve the following beneficial effects:

[0063] 1) The calculated parameter results are closer to the actual measured values;

[0064] 2) Stable and consistent test data is preferred;

[0065] 3) Shorten the calculation time, that is, reduce the overall time of dynamic testing. Attached Figure Description

[0066] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0067] Figure 1 It is an ideal dynamic double-pulse test waveform;

[0068] Figure 2 This is the overall flowchart of the method for calculating the dynamic switching parameters of the power module;

[0069] Figure 3 This is a flowchart of the process parameters for starting up;

[0070] Figure 4 This is a flowchart of the shutdown process parameter calculation;

[0071] Figure 5 The waveforms are taken at 60% and 40% of U1 (V1 and V3 are 40% of U1, and V2 and V4 are 60% of U1).

[0072] Figure 6 It is based on Figure 5 The waveform diagram of the midpoint values ​​calculated from V1, V2, V3, and V4;

[0073] Figure 7 The waveform represents the turn-off process.

[0074] Figure 8 The waveform for the start-up process.

[0075] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0076] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Terms such as "upper," "lower," "left," "right," "middle," and "one" used in the preferred embodiments are merely for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0077] like Figure 1 The ideal dynamic double-pulse test waveform consists of the gate voltage waveform (Vge), the current waveform (Ic), and the bus voltage waveform (Vce). In actual testing, the measured waveform may fluctuate or differ significantly from the actual value due to interference from zero drift, ripple, and oscillation. Therefore, simply calculating the values ​​and locations is insufficient; further waveform processing and calculation are required.

[0078] This invention provides a method for calculating dynamic switching parameters of a power module. The proposed dynamic pulse test parameter calculation calculates the first pulse turn-off and the second pulse turn-on time periods, as well as the various changes and parameter conditions of Vge, vce, and Ic, by calculating the pulse waveform. Table 1 provides a description of the parameters and their values ​​for the turn-on and turn-off calculations.

[0079] Table 1

[0080] 1 <![CDATA[DC power supply voltage U dc > Vce voltage before switching on 2 Gate voltage positive Vge-Pos Vge voltage when the transistor is turned on 3 Gate voltage negative Vge-Neg Vge voltage when the transistor is turned off 4 <![CDATA[Pulse maximum current I CM > Maximum value of Ic 5 Maximum peak current Ic-PK <![CDATA[From 10% of I c to 10% of V ce Peak current]]> 6 Opening time Ton <![CDATA[From 10% of V ge to 90% of I c > 7 <![CDATA[Turn-on delay Td - on > <![CDATA[From 10% of V ge to 10% of I c > 8 <![CDATA[Turn-on current rise time Tr- on > <![CDATA[From 10% of I c to 90% of I c > 9 <![CDATA[Rate of change of turn-on current di / dt - on > <![CDATA[From 50% of I c to 90% of I c > 10 <![CDATA[Turn-on voltage fall time Tf - on > <![CDATA[From 90% of V ce to 10% of V ce > 11 <![CDATA[Rate of change of turn-on voltage dv / dt - on > <![CDATA[From 70% of V ce to 50% of V ce > 12 Enabling loss (Eon) <![CDATA[From 10% of I c to 10% of V ce Integral <!-- 6 -->]]> 13 Turn-off maximum peak voltage Vce-PK Turn-off voltage spike 14 <![CDATA[Turn-off time T off > <![CDATA[From 90% of V ge to 10% of I c > 15 <![CDATA[Turn-off delay Td- off > <![CDATA[From 90% of V ge to 90% of I c > 16 <![CDATA[Turn-off current fall time Tf - off > <![CDATA[From 90% of I c to 10% of I c > 17 <![CDATA[Rate of change of turn-off current di / dt - off > From 90% Ic to 50% Ic 18 <![CDATA[Turn-off voltage rise time Tr- off > <![CDATA[From 10% of V ce to 90% of V ce > 19 <![CDATA[Rate of change of turn-off voltage dv / dt - off > <![CDATA[From 50% of V ce to 70% V ce > 20 <![CDATA[Turn-off loss E off > <![CDATA[Integrate from 10% of V ce to 10% of I c >

[0081] like Figure 2 , 3 As shown in Figure 4, the power module dynamic switching parameter calculation method of the present invention divides the overall test process into three parts: obtaining the midpoint position of the waveform pulse, waveform data zero drift processing, and parameter counting. The specific steps include:

[0082] Step S1: Apply a dynamic double-pulse test waveform to the power module. The double-pulse test waveform consists of the gate voltage waveform Vge, the current waveform Ic, and the bus voltage waveform Vce. Obtain the three waveform data of the gate voltage waveform Vge, the current waveform Ic, and the bus voltage waveform Vce, and calculate the center point position of each pulse.

[0083] Step S2: Perform zero-drift processing on the waveform data of gate voltage waveform Vge, current waveform Ic, and bus voltage waveform Vce respectively;

[0084] Step S3: Based on the three waveform data obtained after eliminating zero drift, calculate the basic parameters Vge-Pos, Vge-Neg, Udc, and ICM. Then, obtain the waveform data of the first pulse turn-off and the second pulse turn-on time periods in the dual pulse, and calculate the turn-off and turn-on process parameters respectively. Based on the percentage of each parameter during the turn-off and turn-on processes, calculate the value of each corresponding parameter, and finally obtain the dynamic switching parameters of the power module.

[0085] The values ​​of each parameter are calculated based on the percentage of each parameter during the shutdown and startup processes, as shown in Table 1. For example, from 10% Vge to 90% Ic, the starting value corresponds to 10% Vge, and the ending value corresponds to 90% Ic. The dynamic switching parameters of the power module refer to parameters such as Ic-PK, Ton, and Td-on in Table 1.

[0086] Specifically, calculating the center point position of each pulse in step S1 includes:

[0087] Calculate the temporary value U1 of the bus voltage waveform Vce. U1 is the average value of the first 50 points of the Vce waveform data. Calculate U60% and U40% based on U1. U60% = 60% × U1, U40% = 40% × U1.

[0088] The system iteratively compares the current voltage value Ud of Vce. When Ud is less than or equal to U40%, the current voltage value V1 is recorded. The comparison continues, and when Ud is greater than or equal to U60%, the current voltage value V2 is recorded. The comparison continues, and when Ud is less than or equal to U40%, the current voltage value V3 is recorded. The comparison continues, and when Ud is greater than or equal to U60%, the current voltage value V4 is recorded.

[0089] Based on the recorded V1, V2, V3, V4, calculate the midpoints T1, T2, T3, T4, and T5 of the lines 0-V1, V1-V2, V2-V3, V3-V4, and V4-end. Then calculate the midpoints T1-1, T2-1, T3-1, T4-1, and T5-1 of the lines T1-V1, T2-V2, T3-V3, T4-V4, and T5-end.

[0090] Specifically, step S2 involves zero-drift processing of the waveform data, which means processing the waveform to eliminate the zero-drift problem. This includes:

[0091] Calculate the average values ​​of Vge from T1 to T1-1, Vge from T2 to T2-1, Vce from T2 to T2-1, and Ic from T1 to T1-1 respectively: VgeT1-T1-1, VgeT2-T2-1, VceT2-T2-1, and IcT1-T1-1.

[0092] Vge zero-drift processing: Calculate the offset Vd of Vge based on the known positive input gate voltage Vge+ and negative gate voltage Vge-. The calculation formula is as follows:

[0093] Vd=(Vge+ - VgeT2-T2-1)-((Vge+ - Vge-)-(VgeT2-T2-1 -VgeT1-T1-1)) / 2

[0094] Then add the offset Vd to all the waveform data of Vge to get the new waveform data Vge-new.

[0095] Vce zero drift processing: Subtract the offset VceT2-T2-1 from all Vce waveform data to obtain new Vce waveform data (Vce-new).

[0096] Ic zero drift processing: Subtract the offset IcT1-T1-1 from all Ic waveform data to obtain the new Ic waveform data Ic-new.

[0097] Specifically, in step S3, based on the three waveform data obtained after eliminating zero drift, the basic parameters Vge-Pos, Vge-Neg, Udc, and ICM are calculated, including:

[0098] Calculate the average values ​​of Vge-new from T1 to T1-1, Vge-new from T2 to T2-1, and Vce-new from T2 to T2-1 respectively to obtain Vge-Pos, Vge-Neg, and Udc; calculate the maximum value of Ic-new from T2 to T3 to obtain ICM.

[0099] Specifically, step S3 involves acquiring the waveform of the first pulse turn-off process and calculating the turn-off process parameters, including:

[0100] Calculation of data for the first pulse turn-off process: Take the waveform data of the T2-T3 portion, starting from time T2 and ending at time T3, as follows: Figure 7 This is the waveform during the turn-off process. The total number of waveform data points from T2 to T3 is obtained and used as the loop count. The current values ​​of the Vge-new, Vce-new, and Ic-new waveform data are obtained sequentially, and then data processing and calculations are performed. During the turn-off process, each parameter is calculated as follows:

[0101] The process iteratively checks whether the current voltage value Vge is less than or equal to 90% of Vge-Pos, and takes the time (ToffS) at that moment. It then iteratively checks whether the current value Ic is greater than or equal to ICM. From that moment, it checks whether the current value Ic is less than or equal to 10% of ICM, taking the time (Ttem). This process is repeated until time T3, at which point the time Ttem is taken, and the time difference between ToffE and ToffS is calculated as the turn-off time (Toff = ToffE - ToffS).

[0102] The system iteratively checks whether the current voltage value Vge is less than or equal to 90% of Vge-Pos, and takes the time (TdoffS) at that moment. It also iteratively checks whether the current value Ic is greater than or equal to ICM, and from that moment on, it continues to check whether the current value Ic is less than or equal to 90% of ICM, taking the time (TdoffE) at that moment. The time difference between TdoffE and TdoffS is calculated as the turn-off delay time (Tdoff = TdoffE - TdoffS).

[0103] The process iteratively checks whether the current value at the new current moment (Ic) is greater than or equal to ICM. From that moment, it checks whether the current value at the new current moment (Ic) is less than or equal to 90% of ICM, and takes the time at that moment (Tf-offS). From that moment, it checks whether the current value at the new current moment (Ic) is less than or equal to 10% of ICM, and takes the time at that moment (Ttem). It then checks whether the current value at the new current moment (Ic) is greater than or equal to 10% of ICM. If so, the time value of Ttem is cleared to zero, and the process is repeated to check whether the current value at the new current moment (Ic) is less than or equal to 10% of ICM, and takes the time at that moment (Ttem). This process is repeated until the end of time T3. The time at the end of time Ttem (Tf-offE) is taken, and the time difference between Tf-offE and Tf-offS is calculated as the turn-off current drop time (Tf-off = Tf-offE - Tf-offS).

[0104] The loop iterates through the current values, checking if the current value at the current instant (Ic) is greater than or equal to ICM. From that instant, it checks if the current value at the current instant (Ic) is less than or equal to 90% of ICM, taking the current value at that instant (IdidtS-off) and the current time (TdidtS-off). From that instant, it checks if the current value at the current instant (Ic) is less than or equal to 50% of ICM, taking the current value at that instant (IdidtE-off) and the current time (TdidtE-off). If, during the transition from 90% to 50% ICM, a later value is larger than an earlier value, the loop exits, and the current current value (IdidtE-off) and current time (TdidtE-off) are taken. The slope from TdidtS-off to TdidtE-off is calculated as the rate of change of the turn-off current (di / dt-off = (IdidtE-off - IdidtS-off) / (TdidtE-off - ...). TdidtS-off).

[0105] The process iteratively checks whether the current voltage value at time Vce is greater than or equal to 10% of Udc, and takes the time at that moment (Tr-offS). Then it checks whether the current voltage value at time Vce is greater than or equal to 90% of Udc, and takes the time at that moment (Ttem). Then it checks whether the current voltage value at time Vce is less than or equal to 90% of Udc. If so, the time value of Ttem is cleared to zero, and the process is repeated to check whether the current voltage value at time Vce is greater than or equal to 90% of Udc, and takes the time at that moment (Ttem). This process is repeated until time T3 ends. The time at time Ttem (Tr-offE) is then taken. The time difference between Tr-offE and Tr-offS is calculated as the turn-off voltage rise time (Tr-off = Tr-offE - Tr-offS).

[0106] The loop iterates through the data, checking if the current voltage value (Vce) is greater than or equal to 50% of Udc, taking the voltage value at that moment (UdvdtS-off) and the current time (TdvdtS-off). From that moment, it continues checking if the current voltage value (Vce) is greater than or equal to 70% of Udc, taking the voltage value at that moment (UdvdtE-off) and the current time (TdvdtE-off). If, during the transition from 50% Udc to 70% Udc, a later value is smaller than an earlier value, the loop exits, and the current voltage value (UdvdtE-off) and current time (TdvdtE-off) are taken. The slope from TdvdtS-off to TdvdtE-off is calculated as the rate of change of the turn-off voltage (dv / dt-off = (UdvdtE-off - UdvdtS-off) / (TdvdtE-off - ...). TdvdtS-off).

[0107] The process iteratively checks whether the current voltage value of Vce-new is greater than or equal to 10% of Udc, and records the time at that moment (TEoffS). It then iteratively checks whether the current value of Ic-new is greater than or equal to ICM. From that moment, it checks whether the current value of Ic-new is less than or equal to 10% of ICM, recording the time at that moment (Ttem). This process is repeated until moment T3, at which point the time at Ttem (TEoffE) is recorded. The integral of the product of Vce-new and Ic-new during the time interval from TEoffS to TEoffE is the turn-off loss. .

[0108] The system iteratively compares the current voltage value (Vce) with the temporary voltage value (Vtem), storing the larger value in the temporary voltage value (Vtem) until the loop ends. The Vtem voltage value is then retrieved as the maximum turn-off peak voltage (Vce-PK).

[0109] Specifically, step S3 involves acquiring the waveform of the second pulse turn-on process and calculating the turn-on process parameters, including:

[0110] Second pulse activation process data calculation: Take the waveform data of the T3-T4 section, starting from time T3 and ending at time T4, such as... Figure 8 The waveform for the activation process is as follows. The total number of waveform data points from T3 to T4 is obtained and used as the loop count. The current values ​​of the Vge-new, Vce-new, and Ic-new waveform data are obtained sequentially, and then data processing and calculation are performed. During the activation process, each parameter is calculated as follows:

[0111] The system iteratively checks whether the current voltage value of Vge is greater than or equal to 10% of Vge-Pos, and then takes the time (TonS) at that moment.

[0112] The process involves sequentially checking whether the current value at the new current moment (Ic) is greater than or equal to 90% of the ICM, taking the time (Ttem) at that moment, and then checking whether the current value at the new current moment (Ic) is less than or equal to 90% of the ICM. If so, the Ttem time value is cleared to zero, and the process is repeated until the end of time T4. The Ttem time value (TonE) is then taken, and the time difference between TonE and TonS is calculated as the turn-on time (Ton = TonE - TonS).

[0113] The system iteratively checks whether the current voltage value Vge is greater than or equal to 10% of Vge-Pos and takes the time (TdonS) at that moment. It also iteratively checks whether the current current value Ic is greater than or equal to 10% of ICM and takes the time (TdonE) at that moment. The time difference between TdonE and TdonS is calculated as the turn-on delay time (Tdon = TdonE - TdonS).

[0114] The process iteratively checks whether the current value at the new current moment (Ic) is greater than or equal to 10% of ICM, and takes the time at that moment (Tr-onS). From that moment, it checks whether the current value at the new current moment (Ic) is greater than or equal to 90% of ICM, and takes the time at that moment (Ttem). Then it checks whether the current value at the new current moment (Ic) is less than or equal to 90% of ICM. If so, the time value of Ttem is cleared to zero, and the process is repeated to check whether the current value at the new current moment (Ic) is greater than or equal to 90% of ICM, and takes the time at that moment (Ttem). This process is repeated until the end at time T4. The time at time Ttem (Tr-onE) is then taken. The time difference between Tr-onE and Tr-onS is calculated as the turn-on current rise time (Tr-on = Tr-onE - Tr-onS).

[0115] The loop iterates through the current values, checking whether the current value at the current moment is greater than or equal to 50% of the ICM. It takes the current value at that moment (IdidtS-on) and the current time (TdidtS-on). From that moment on, it continues to check whether the current value at the current moment is greater than or equal to 90% of the ICM. It takes the current value at that moment (IdidtE-on) and the current time (TdidtE-on). If, during the process from 50% to 90% of the ICM, the value of the later value is smaller than the value of the earlier value, the loop exits. It takes the current value at the current moment (IdidtE-on) and the current time (TdidtE-on). The slope from TdidtS-on to TdidtE-on is calculated as the rate of change of the turn-on current (di / dt-on = (IdidtE-on - IdidtS-on) / (TdidtE-on - TdidtS-on)).

[0116] The process iteratively checks whether the current voltage value of Vce is less than or equal to 90% of Udc, and takes the time of that moment (Tf-onS). Then it checks whether the current voltage value of Vce is less than or equal to 10% of Udc, and takes the time of that moment (Ttem). Then it checks whether the current voltage value of Vce is greater than or equal to 10% of Udc. If so, the Ttem time value is cleared to zero, and the process is repeated to check whether the current voltage value of Vce is less than or equal to 10% of Udc, and takes the time of that moment (Ttem). This process is repeated until the end of time T4. The time of Ttem is then taken as (Tf-onE). The time difference between Tf-onE and Tf-onS is calculated as the turn-on voltage drop time (Tf-on = Tf-onE - Tf-onS).

[0117] The loop iterates through the following steps: It checks if the current voltage value (Vce) is less than or equal to 70% of Udc, taking the voltage value at that moment (UdvdtS-on) and the current time (TdvdtS-on). From that moment on, it checks if the current voltage value (Vce) is less than or equal to 50% of Udc, taking the voltage value at that moment (UdvdtE-on) and the current time (TdvdtE-on). If, during the transition from 70% Udc to 50% Udc, a later value is larger than an earlier value, the loop exits, and the current voltage value (UdvdtE-on) and current time (TdvdtE-on) are retrieved. The slope from TdvdtS-on to TdvdtE-on is calculated as the rate of change of the turn-on voltage (dv / dt-on = (UdvdtE-on - UdvdtS-on) / (TdvdtE-on)). -TdvdtS-on).

[0118] The process iteratively checks whether the current value of Ic-new at the current moment is greater than or equal to 10% of ICM, and records the time at that moment (TEonS). It then iteratively checks whether the current voltage value of Vce-new at the current moment is less than or equal to 10% of Udc, and records the time at that moment (Ttem). This process is repeated until moment T4, at which point the time at Ttem (TEonE) is recorded. The integral of the product of Ic-new and Vce-new during the time interval from TeonS to TeonE is the opening loss. .

[0119] The process iteratively checks whether the current value of Ic-new at the current moment is greater than or equal to 10% of ICM, and takes the time of that moment (TIc-pkS). Iteratively checks whether the voltage value of Vce-new at the current moment is less than or equal to 2% of Udc, and takes the time of that moment (Ttem). It then continues to check whether the voltage value of Vce-new at the current moment is greater than or equal to 2% of Udc. If it is, the time value of Ttem is cleared to zero, and the process continues to check whether the voltage value of Vce-new at the current moment is less than or equal to 2% of Udc, and takes the time of that moment (Ttem). This process is repeated until the end of time T4. The time of Ttem is then taken as (TIc-pkE). The maximum peak current of Ic-new during the time period from TIc-pkS to TIc-pkE is calculated as the turn-on peak current Ic-PK.

[0120] Because dynamic testing has high time requirements, the calculation of parameter data must be as time-efficient as possible. Therefore, in this invention, the three waveforms are processed simultaneously during zero-drift processing, which reduces the zero-drift processing time by 2 / 3. Furthermore, during data calculation, the data from the turn-on and turn-off processes are calculated simultaneously, reducing the data calculation time by 1 / 2. In addition, all data can be calculated in a single loop during the turn-on and turn-off processes, further reducing the overall calculation time.

[0121] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for calculating dynamic switching parameters of a power module, characterized in that, Includes the following steps: S1. The power module is tested using a dynamic double-pulse test waveform, which consists of a gate voltage waveform Vge, a current waveform Ic, and a bus voltage waveform Vce. The three waveform data are obtained: gate voltage waveform Vge, current waveform Ic, and bus voltage waveform Vce. The center point position of each pulse is calculated. S2. Perform zero-drift processing on the waveform data of gate voltage waveform Vge, current waveform Ic and bus voltage waveform Vce respectively. S3. Based on the three waveform data obtained after eliminating zero drift, calculate the basic parameters Vge-Pos, Vge-Neg, Udc, and ICM. Then, obtain the waveform data of the first pulse turn-off and the second pulse turn-on time periods in the dual-pulse process, and calculate the turn-off and turn-on process parameters respectively. Based on the percentage of each parameter during the turn-off and turn-on processes, calculate the values ​​of the corresponding parameters, and finally obtain the dynamic switching parameters of the power module; among which, Step S2 involves zero-drift processing of the waveform data, specifically including: Process the waveform: Calculate the average values ​​of Vge from T1 to T1-1, Vge from T2 to T2-1, Vce from T2 to T2-1, and Ic from T1 to T1-1 respectively: VgeT1-T1-1, VgeT2-T2-1, VceT2-T2-1, IcT1-T1-1. Eliminate zero drift: Vge zero-drift processing: Calculate the offset Vd of Vge based on the known positive input gate voltage Vge+ and negative gate voltage Vge-. The calculation formula is as follows: Vd=(Vge+ - VgeT2-T2-1)-((Vge+ - Vge-)-(VgeT2-T2-1 -VgeT1-T1-1)) / 2 Then add the offset Vd to all the waveform data of Vge to get the new waveform data Vge-new; Vce zero drift processing: Subtract the offset VceT2-T2-1 from all Vce waveform data to obtain the new Vce waveform data Vce-new; Ic zero drift processing: Subtract the offset IcT1-T1-1 from all Ic waveform data to obtain the new Ic waveform data Ic-new; In step S3, based on the three waveform data obtained after eliminating zero drift, the basic parameters Vge-Pos, Vge-Neg, Udc, and ICM are calculated, specifically including: Calculate the average values ​​of Vge-new from T1 to T1-1, Vge-new from T2 to T2-1, and Vce-new from T2 to T2-1 respectively to obtain Vge-Pos, Vge-Neg, and Udc; Calculate the maximum value of Ic from T2 to T3 to obtain ICM.

2. The method for calculating dynamic switching parameters of a power module according to claim 1, characterized in that, Step S1 calculates the center point position of each pulse, specifically including: Calculate the temporary value U1 of the bus voltage waveform Vce. U1 is the average value of the first 50 points of the Vce waveform data. Calculate U60% and U40% based on U1, where U60% = 60% × U1 and U40% = 40% × U1. The system iteratively compares the current voltage value Ud of Vce. When Ud is less than or equal to U40%, the current voltage value V1 is recorded. The comparison continues, and when Ud is greater than or equal to U60%, the current voltage value V2 is recorded. The comparison continues, and when Ud is less than or equal to U40%, the current voltage value V3 is recorded. The comparison continues, and when Ud is greater than or equal to U60%, the current voltage value V4 is recorded. Based on the recorded V1, V2, V3, V4, calculate the midpoints T1, T2, T3, T4, and T5 of the lines 0-V1, V1-V2, V2-V3, V3-V4, and V4-end. Then calculate the midpoints T1-1, T2-1, T3-1, T4-1, and T5-1 of the lines T1-V1, T2-V2, T3-V3, T4-V4, and T5-end.

3. The method for calculating dynamic switching parameters of a power module according to claim 2, characterized in that, In step S3, the waveform of the first pulse turn-off process is acquired, and the turn-off process parameters are calculated, specifically including: Take the waveform data of the T2-T3 section, starting from time T2 and ending at time T3, which is the waveform of the turn-off process; Obtain the total number of waveform data from T2 to T3, and use this as the loop count to iterate. Sequentially obtain the current values ​​of the waveform data for Vge-new, Vce-new, and Ic-new, and then perform data processing calculations. During the shutdown process, each parameter is calculated as follows: The process iteratively checks whether the current voltage value Vge is less than or equal to 90% of Vge-Pos, and takes the time ToffS for that moment. It then iteratively checks whether the current value Ic is greater than or equal to ICM. From that moment, it checks whether the current value Ic is less than or equal to 10% of ICM, taking the time Ttem for that moment. This process is repeated until time T3. The time ToffE for Ttem is then calculated, and the time difference between ToffE and ToffS is used as the turn-off time. Toff = ToffE – ToffS; The system iteratively checks whether the current voltage value (Vge - Pos) is less than or equal to 90% of Vge - Pos, and takes the time TdoffS for that moment. It also iteratively checks whether the current value (Ic - Ic) is greater than or equal to ICM, and from that moment on, it continues to check whether the current value (Ic - Ic) is less than or equal to 90% of ICM, taking the time TdoffE for that moment. The time difference between TdoffE and TdoffS is calculated as the turn-off delay time using the following formula: Tdoff = TdoffE – TdoffS; The process iteratively checks whether the current value at the new current moment (Ic) is greater than or equal to ICM. From that moment, it checks whether the current value at the new current moment (Ic) is less than or equal to 90% of ICM, taking the time Tf-offS. From that moment, it checks whether the current value at the new current moment (Ic) is less than or equal to 10% of ICM, taking the time Ttem. It then checks whether the current value at the new current moment (Ic) is greater than or equal to 10% of ICM. If so, the time Ttem is reset to zero, and the process repeats until the end at time T3. The time Tf-offE at time Ttem is then calculated. The time difference between Tf-offE and Tf-offS is calculated as the turn-off current drop time using the following formula: Tf-off = Tf-offE - Tf-offS; The loop iterates through the current values, checking whether the current value at the current instant (Ic - the new current instant) is greater than or equal to ICM. From that instant, it checks whether the current value at the current instant (Ic - the new current instant) is less than or equal to 90% of ICM, taking the current value IdidtS-off and the current time TdidtS-off. From that instant, it checks whether the current value at the current instant (Ic - the new current instant) is less than or equal to 50% of ICM, taking the current value IdidtE-off and the current time TdidtE-off. If a later value is larger than a previous value during the transition from 90% to 50% ICM, the loop exits, and the current current value IdidtE-off and the current time TdidtE-off are taken. The slope from TdidtS-off to TdidtE-off is calculated as the rate of change of the turn-off current using the following formula: di / dt-off = (IdidtE-off - IdidtS-off) / (TdidtE-off - TdidtS-off)); The algorithm iteratively checks whether the current voltage value at time Vce is greater than or equal to 10% of Udc, taking the time Tr-offS for that moment. It then checks whether the current voltage value at time Vce is greater than or equal to 90% of Udc, taking the time Ttem for that moment. Next, it checks whether the current voltage value at time Vce is less than or equal to 90% of Udc. If so, the time Ttem is reset to zero, and the algorithm repeats the process until time T3 ends. The time Tr-offE at time Ttem is then calculated. The time difference between Tr-offE and Tr-offS is calculated as the turn-off voltage rise time using the following formula: Tr-off = Tr-offE - Tr-offS; The loop iterates through the data, checking whether the current voltage value (Vce) is greater than or equal to 50% of Udc. It then takes the voltage value UdvdtS-off at that moment and the current time TdvdtS-off. From that moment on, it continues to check whether the current voltage value (Vce) is greater than or equal to 70% of Udc. It takes the voltage value UdvdtE-off at that moment and the current time TdvdtE-off. If, during the transition from 50% Udc to 70% Udc, a later value is smaller than an earlier value, the loop exits. The current voltage value UdvdtE-off and the current time TdvdtE-off are then taken. The slope from TdvdtS-off to TdvdtE-off is calculated using the following formula, representing the rate of change of the turn-off voltage: dv / dt-off = (UdvdtE-off - UdvdtS-off) / (TdvdtE-off - TdvdtS-off); The process iteratively checks whether the current voltage value of Vce-new is greater than or equal to 10% of Udc, and takes the time TEoffS for that moment. It then iteratively checks whether the current value of Ic-new is greater than or equal to ICM. From that moment on, it checks whether the current value of Ic-new is less than or equal to 10% of ICM, taking the time Ttem for that moment. This process is repeated until time T3 ends. The time Ttem is then taken, and the integral of the product of Vce-new and Ic-new during the time interval from TEoffS to TEoffE is calculated as the turn-off loss: ； The system iteratively compares the current voltage value Vce with the temporary voltage value Vtem, storing the larger value in the temporary voltage value Vtem. This process continues until the loop ends, at which point the voltage value Vtem is retrieved as the maximum turn-off peak voltage Vce-PK.

4. The method for calculating dynamic switching parameters of a power module according to claim 3, characterized in that, In step S3, the waveform of the second pulse turn-on process is obtained, and the turn-on process parameters are calculated, specifically including: Take the waveform data from T3 to T4, starting from time T3 and ending at time T4, which is the waveform of the start-up process; Obtain the total number of waveform data points from T3 to T4, and use this as the loop count to iterate. Sequentially obtain the current values ​​of the Vge-new, Vce-new, and Ic-new waveform data, and then perform data processing calculations. During the activation process, each parameter is calculated as follows: The process iteratively checks whether the current voltage value (Vge - Pos) is greater than or equal to 10% of Vge - Pos, and takes the time TonS for that moment. It then checks whether the current value (Ic - Ic) is greater than or equal to 90% of ICM, and takes the time Ttem for that moment. This process is repeated until time T4, at which point the time TonE is taken. The difference between TonE and TonS is calculated using the following formula as the turn-on time: Ton = TonE - TonS; The system iteratively checks whether the current voltage value (Vge) is greater than or equal to 10% of Vge - Pos, and takes the time TdonS at that moment. It also iteratively checks whether the current current value (Ic) is greater than or equal to 10% of ICM, and takes the time TdonE at that moment. The time difference between TdonE and TdonS is calculated using the following formula as the turn-on delay time: Tdon = TdonE–TdonS; The process iteratively checks whether the current value at the current instant Ic is greater than or equal to 10% of ICM, taking the time Tr-onS for that instant. From that instant, it checks whether the current value at the current instant Ic is greater than or equal to 90% of ICM, taking the time Ttem for that instant. Then it checks whether the current value at the current instant Ic is less than or equal to 90% of ICM. If so, the time Ttem is reset to zero, and the process is repeated until the end of the cycle at time T4. The time Tr-onE for Ttem is then calculated. The time difference between Tr-onE and Tr-onS is calculated as the turn-on current rise time using the following formula: Tr-on = Tr-onE - Tr-onS; The loop iterates through the current values, checking whether the current value at the current instant (Ic - the new current value) is greater than or equal to 50% of the ICM. It takes the current value IdidtS-on at that instant and the current time TdidtS-on. From that instant, it continues to check whether the current value at the current instant (Ic - the new current value) is greater than or equal to 90% of the ICM, taking the current value IdidtE-on at that instant and the current time TdidtE-on. If, during the transition from 50% to 90% of the ICM, a later value is smaller than an earlier value, the loop exits, and the current current value IdidtE-on and the current time TdidtE-on are retrieved. The slope from TdidtS-on to TdidtE-on is calculated as the rate of change of the turn-on current. di / dt-on = (IdidtE-on - IdidtS-on) / (TdidtE-on - TdidtS-on); The process iteratively checks whether the current voltage value of Vce is less than or equal to 90% of Udc, taking the time Tf-onS. It then checks whether the current voltage value of Vce is less than or equal to 10% of Udc, taking the time Ttem. This process is repeated until time T4. The time Tf-onE is then taken, and the time difference between Tf-onE and Tf-onS is calculated as the turn-on voltage drop time using the following formula: Tf-on = Tf-onE - Tf-onS; The loop iterates through the current voltage value (Vce) to determine if it is less than or equal to 70% of Udc. It then takes the voltage value UdvdtS-on at that moment and the current time TdvdtS-on. From that moment on, it continues to determine if the current voltage value (Vce) is less than or equal to 50% of Udc. It takes the voltage value UdvdtE-on at that moment and the current time TdvdtE-on. If, during the transition from 70% Udc to 50% Udc, a later value is greater than an earlier value, the loop exits. The loop then takes the current voltage value UdvdtE-on and the current time TdvdtE-on, and calculates the slope from TdvdtS-on to TdvdtE-on as the rate of change of the turn-on voltage using the following formula: dv / dt-on = (UdvdtE-on - UdvdtS-on) / (TdvdtE-on - TdvdtS-on); The process iteratively checks whether the current value of Ic-new at the current moment is greater than or equal to 10% of ICM, and takes the time TEonS for that moment. Iteratively checks whether the current voltage value of Vce-new at the current moment is less than or equal to 10% of Udc, and takes the time Ttem for that moment. This process is repeated until time T4, at which point the time TEonE is taken. The integral of the product of Ic-new and Vce-new during the time interval from TEonS to TEonE is then calculated as the open-circuit loss: ； The process iteratively checks whether the current value of Ic-new at the current moment is greater than or equal to 10% of ICM, and takes the time TIc-pkS for that moment. Iteratively checks whether the voltage value of Vce-new at the current moment is less than or equal to 2% of Udc, and takes the time Ttem for that moment. It then continues to check whether the voltage value of Vce-new at the current moment is greater than or equal to 2% of Udc. If it is, the time value Ttem is cleared to zero, and the process continues to check whether the voltage value of Vce-new at the current moment is less than or equal to 2% of Udc, and takes the time Ttem for that moment. This process is repeated until the end of time T4. The time Ttem is then taken as TIc-pkE. The maximum peak current of Ic-new during the time period from TIc-pkS to TIc-pkE is calculated as the turn-on peak current Ic-PK.

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