An FFT-based short-circuit failure simulation model frequency domain evaluation method for IGBT devices

Abstract

The application belongs to the technical field of semiconductor, and particularly relates to a frequency domain evaluation method for an IGBT device short-circuit failure simulation model based on FFT. The method comprises the following steps: S1, obtaining a fundamental frequency according to a short-circuit duration; S2, performing simulation waveform analysis on voltage and current waveforms in the short-circuit duration process to obtain a total harmonic content THD 仿真 ; S3, comparing the total harmonic content THD 仿真 obtained by simulation waveform analysis with the total harmonic content THD 实测 obtained by actual waveform analysis, as a quantitative index for consistency between the short-circuit failure simulation model and actual device short-circuit characteristics. The application provides a clear quantitative index, improves the evaluation capability of the IGBT short-circuit failure model, provides better support for full working condition design and selection of devices such as frequency converters, improves the design efficiency, and reduces the research and development cycle and cost.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically a frequency domain evaluation method for a simulation model of short-circuit failure of IGBT devices based on FFT. Background Technology

[0002] IGBTs, semiconductor devices, possess advantages such as fully controllable switching, high withstand voltage ratings, large current carrying capacity, high switching frequency, and low drive power, making them the most widely used power electronic switching devices in medium- and high-power applications such as frequency converters. During the use of IGBTs, to ensure device failure, it is necessary to adhere to the IGBT's safe operating areas, including: the forward-biased safe operating area, the reverse-biased safe operating area, and the short-circuit safe operating area. IGBTs are most susceptible to damage during short-circuit switching. While numerous studies have simulated and analyzed the short-circuit switching process of IGBTs, suitable quantitative indicators are lacking for evaluating the accuracy of short-circuit failure simulation models.

[0003] IGBT short-circuit failure simulation models are used to analyze the voltage and current stress changes of IGBT devices during short-circuit processes. When applying these models to short-circuit simulation tests on devices such as frequency converters, it's possible to better analyze the electrical stress changes of IGBT devices under various operating conditions, thus providing guidance for IGBT device selection and circuit design during device design. Currently, there is no effective quantitative indicator for evaluating the accuracy of IGBT short-circuit failure simulation models. Most literature only compares the peak values ​​and shapes of voltage and current curves during short-circuit processes. While this comparison without quantitative indicators may be sufficient under the normal steady-state operating conditions of frequency converters, it is insufficient to intuitively and comprehensively reflect the accuracy of short-circuit failure simulation models when studying the switching characteristics of IGBT devices under all operating conditions of frequency converters, especially during short-circuit processes. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a frequency domain evaluation method for a simulation model of short-circuit failure of IGBT devices based on FFT.

[0005] This invention adopts the following technical solution: a frequency domain evaluation method for a simulation model of short-circuit failure of IGBT devices based on FFT, comprising:

[0006] S1: The fundamental frequency is obtained based on the duration of the short circuit;

[0007] S2: Simulate and analyze the voltage and current waveforms during the short-circuit duration to obtain the total harmonic distortion (THD). 仿真 ;

[0008] S3: The total harmonic content (THD) obtained from the simulation waveform analysis仿真 Total Harmonic Distortion (THD) obtained from measured waveform analysis 实测 The comparison is used as a quantitative indicator of the consistency between the short-circuit failure simulation model and the short-circuit characteristics of the actual device.

[0009] In some embodiments, in step S1, the fundamental frequency is 1 / T X T X =t e -t s , where t s t is the start time of the short circuit continuation. e This is the end point of the short circuit duration.

[0010] In some embodiments, the starting time is voltage V. ce The moment when the voltage first begins to drop to 90% of the rated voltage; the end moment is the voltage V. ce The peak of the fluctuation after the highest value is when it is less than 30% of the highest point.

[0011] In some embodiments, in step S2, the highest frequency of the FFT analysis is 100 times the fundamental frequency.

[0012] In some embodiments, in step S2, the total harmonic content (THD) 仿真 Includes: THD 仿真电压 and THD 仿真电流 .

[0013] In some embodiments, in step S3, the total harmonic content (THD) 实测 Includes: THD 实测电压 and THD 实测电流 .

[0014] In some embodiments, step S3 includes:

[0015] S31: Calculate the overlap of voltage waveforms overlap with current waveform ,

[0016]

[0017] ;

[0018] S32: Calculate the accuracy of the final device transient model P , ;

[0019] Model accuracy P The smaller the value, the closer the IGBT short-circuit failure simulation model is to the actual characteristics of the IGBT device.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] Compared to the current method of manually comparing short-circuit characteristic curves, this invention proposes clear quantitative indicators, which improves the evaluation capability of IGBT short-circuit failure models, provides better support for the full-condition design and selection of devices such as frequency converters, improves design efficiency, and reduces the R&D cycle and cost.

[0022] This invention provides a method for controlling the collector-emitter voltage V during a short circuit. ce and collector current I c The method of performing FFT analysis separately, and using the overlap of the harmonic content (THD) as a quantitative index for short-circuit failure model evaluation, improves the evaluation capability of IGBT short-circuit failure model.

[0023] This invention provides better support for the design and selection of devices such as frequency converters under all operating conditions, improves design efficiency, and reduces the development cycle and cost. Attached Figure Description

[0024] Figure 1 This invention provides simulated and measured voltage and current waveforms of an IGBT device during a short circuit process.

[0025] Figure 2 The simulated and measured voltage and current waveforms during the short-circuit process of Model 2;

[0026] Figure 3 The present invention provides an FFT analysis spectrum and THD value of the measured voltage during the short-circuit process of an IGBT device.

[0027] Figure 4 The present invention provides an FFT analysis spectrum and THD value of the simulated voltage during the short-circuit process of an IGBT device.

[0028] Figure 5 The present invention provides an FFT analysis spectrum and THD value of the measured current during the short-circuit process of an IGBT device.

[0029] Figure 6 The present invention provides an FFT analysis spectrum and THD value of the simulated current during the short-circuit process of an IGBT device.

[0030] Figure 7 The voltage FFT analysis spectrum and THD value for Model 2;

[0031] Figure 8 The current FFT analysis spectrum and THD value for Model 2;

[0032] Figure 9This is a flowchart of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] A frequency domain evaluation method for short-circuit failure simulation models of IGBT devices based on FFT, comprising:

[0035] S1: The fundamental frequency is obtained based on the duration of the short circuit.

[0036] Figure 1 The curve in the middle represents the short-circuit failure process of an IGBT device, including V obtained from simulation model testing and actual device testing. ce and I c The fundamental period set for the FFT analysis is the duration T of the device's short-circuit state from the start to the end. X The initial time is the voltage V. ce The moment t when the voltage first begins to drop to 90% of the rated voltage s The end time is the voltage V. ce The time t when the peak of the fluctuation after the highest value is less than 30% of the highest point. e Then T X =t e -t s The fundamental frequency is 1 / T X .

[0037] S2: Simulate and analyze the voltage and current waveforms during the short-circuit duration to obtain the total harmonic distortion (THD). 仿真 .

[0038] Considering the degree of overlap of high-frequency oscillations during the short-circuit process, in order to improve the accuracy of the analysis, the highest frequency of the FFT analysis is set to 100 times the fundamental frequency.

[0039] S3: The total harmonic content (THD) obtained from the simulation waveform analysis 仿真 Total Harmonic Distortion (THD) obtained from measured waveform analysis 实测 The comparison is used as a quantitative indicator of the consistency between the short-circuit failure simulation model and the short-circuit characteristics of the actual device.

[0040] Figures 2-5 These are the spectrum and THD content obtained from FFT analysis of the IGBT device during the short circuit process, respectively.实测电压 THD 仿真电压 THD 实测电流 and THD 仿真电流 .

[0041] This patent proposes a simulated curve for THD. 仿真 THD of content versus measured curve 实测 The closer the value is to the actual short-circuit failure model, the higher the accuracy of the model and the more it matches the actual short-circuit characteristics of the device.

[0042] The overlap of voltage waveforms is The overlap of the current waveforms is :

[0043] (1)

[0044] (2)

[0045] Accuracy of the final device transient model for:

[0046] (3)

[0047] Accuracy P The smaller the value, the closer the IGBT short-circuit failure simulation model is to the actual characteristics of the IGBT device.

[0048] This invention primarily focuses on frequency domain evaluation of short-circuit failure models for semiconductor IGBT devices. For short-circuit failure models of other similar semiconductor devices, including those with different packaging forms, voltage levels, and capacity levels, the method provided in this patent can be referenced.

[0049] A short-circuit failure simulation model was established for a certain type of IGBT. Model 1 is an improved version of the Hefner model, which has been verified and is superior to Model 2. Model 2 is the classic Hefner model. Taking Model 1 and Model 2 as examples, the short-circuit failure simulation waveform of Model 1 is as follows: Figure 1 The short-circuit failure simulation waveform of Model 2 is as follows: Figure 2 :

[0050] like Figure 2 As shown, the initial time is the voltage V. ce The first time the voltage begins to drop to 90% of the rated voltage is 1.6µs; the end time is when the voltage V... ce The time when the peak value of the fluctuation after the highest value is less than 30% of the highest point is 12.49 μs. Therefore, the short-circuit duration is T. X =9.6us, set the fundamental frequency to 83.4KHz.

[0051] Voltage and current FFT analysis of the true short-circuit characteristics of the device, as follows: Figure 3 and Figure 5 As shown.

[0052] The voltage and current FFT analysis of Model 1 is as follows: Figure 4 and Figure 6 As shown.

[0053] The voltage and current FFT analysis of Model 2 is as follows: Figure 7 , 8 As shown.

[0054] The actual voltage waveform (THD) of an IGBT device under short-circuit conditions. 实测电压 The actual current waveform THD is 599.18%. 实测电流 The total harmonic distortion (THD) is 129.77%. The THD indices for Model 1 and Model 2 are summarized in the table below:

[0055]

[0056] Model 1 P The metric is clearly superior to Model 2. P The performance indicators show that short-circuit failure simulation model 1 is actually superior to short-circuit failure model 2. Verification has shown that the frequency domain evaluation method for the IGBT device short-circuit failure simulation model based on FFT proposed in this patent can validate the effectiveness of the IGBT device short-circuit failure model.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A frequency domain evaluation method for short-circuit failure simulation models of IGBT devices based on FFT, characterized in that, include: S1: The fundamental frequency is obtained based on the duration of the short circuit; The fundamental frequency is 1 / T X T X =t e -t s , where t s t is the start time of the short circuit continuation. e This is the moment when the short circuit ends. The initial time is the voltage V ce The moment when the voltage first begins to drop to 90% of the rated voltage; The end time is the voltage V ce The moment when the peak of the fluctuation after the highest value is less than 30% of the highest point; S2: Simulate and analyze the voltage and current waveforms during the short-circuit duration to obtain the total harmonic distortion (THD). 仿真 ; S3: The total harmonic content (THD) obtained from the simulation waveform analysis 仿真 Total Harmonic Distortion (THD) obtained from measured waveform analysis 实测 The comparison is used as a quantitative indicator of the consistency between the short-circuit failure simulation model and the short-circuit characteristics of the actual device.

2. The frequency domain evaluation method for IGBT device short-circuit failure simulation model based on FFT according to claim 1, characterized in that, In step S2, the highest frequency of the FFT analysis is 100 times the fundamental frequency.

3. The frequency domain evaluation method for IGBT device short-circuit failure simulation model based on FFT according to claim 1, characterized in that, In step S2, the total harmonic content (THD) 仿真 Includes: THD 仿真电压 and THD 仿真电流 .

4. The frequency domain evaluation method for IGBT device short-circuit failure simulation model based on FFT according to claim 3, characterized in that, In step S3, the total harmonic content (THD) 实测 Includes: THD 实测电压 and THD 实测电流 .

5. The frequency domain evaluation method for IGBT device short-circuit failure simulation model based on FFT according to claim 4, characterized in that, Step S3 includes: S31: Calculate the overlap of voltage waveforms overlap with current waveform , ； S32: Calculate the accuracy of the final device transient model P , ; Accuracy P The smaller the value, the closer the IGBT short-circuit failure simulation model is to the actual characteristics of the IGBT device.

Images