Periodic temperature fluctuation distribution calculation method and system, medium and equipment

Abstract

The invention discloses an IGBT module periodic temperature fluctuation distribution calculation method, system, medium and equipment, and the method comprises the steps: building a frequency domain finite element thermal model according to an actual three-dimensional geometric structure and material characteristics of an IGBT module, and employing a Robin boundary condition to describe a heat transfer relation between the IGBT module and a radiator; a frequency domain loss model of the IGBT module is established, modeling is carried out on conduction loss and switching loss of an IGBT chip and an FWD chip, and a frequency domain expression of periodic loss is obtained through Fourier transform; and executing an iterative calculation process, solving a steady-state heat conduction equation based on the average loss, obtaining average temperature distribution to serve as reference temperature to be substituted into the frequency domain loss model, solving temperature fluctuation response corresponding to each order of harmonic wave in the frequency domain to obtain amplitude and phase angle of each time of temperature fluctuation, and performing frequency-time domain transformation to obtain a frequency-domain loss model. And converting the temperature response in the frequency domain into periodic steady-state temperature fluctuation distribution in the time domain.

Description

Technical Field

[0001] This invention relates to the field of IGBT module testing technology, and in particular to a method, system, medium, and device for calculating the periodic temperature fluctuation distribution of an IGBT module. Background Technology

[0002] IGBT modules are core components of power electronic equipment such as wind turbine converters, photovoltaic inverters, and flexible DC transmission converter valves, and their reliability directly affects the safe and stable operation of these devices. Periodic temperature fluctuations during long-term operation are a major cause of IGBT module degradation; therefore, efficiently calculating the periodic temperature fluctuation distribution of IGBT modules is crucial for IGBT module reliability assessment.

[0003] The information disclosed in the background section is only for enhancing the understanding of the background of this invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] This invention provides a method, system, medium, and device for calculating the periodic temperature fluctuation distribution of an IGBT module, which can quickly and efficiently obtain the periodic temperature fluctuation distribution of the IGBT module.

[0005] A method for calculating the periodic temperature fluctuation distribution of an IGBT module includes:

[0006] Step 1: Establish a frequency domain finite element thermal model based on the actual three-dimensional geometric structure and material properties of the IGBT module. The governing equation of the frequency domain finite element thermal model is a steady-state heat conduction equation in frequency domain form. The boundary conditions are Robin boundary conditions to describe the heat transfer relationship between the IGBT module and the heat sink.

[0007] Step 2: Establish the frequency domain loss model of the IGBT module. This involves modeling the conduction and switching losses of the IGBT chip and the FWD chip. The total loss of the chip is the sum of the conduction and switching losses. The frequency domain expression of the periodic loss is obtained using Fourier transform, which includes the average loss, the amplitude of each harmonic loss, and the phase angle.

[0008] Step 3: Perform iterative calculation. The steady-state heat conduction equation is solved based on the average loss to obtain the average temperature distribution, which is then used as a reference temperature and substituted into the frequency domain loss model. The temperature fluctuation response corresponding to each harmonic is solved in the frequency domain to obtain the amplitude and phase angle of each temperature fluctuation. Through frequency-time domain transformation, the temperature response in the frequency domain is converted into a periodic steady-state temperature fluctuation distribution in the time domain.

[0009] In the method for calculating the periodic temperature fluctuation distribution of an IGBT module, the steady-state heat conduction equation is:

[0010] Where ρ is density, c is specific heat capacity, λ is thermal conductivity, ω is frequency, T is temperature, i is imaginary unit, and xyz is coordinate Φ. s It serves as a heat source.

[0011] In the method for calculating the periodic temperature fluctuation distribution of an IGBT module, the Robin boundary condition is used to describe the heat transfer relationship between the IGBT module and the heat sink:

[0012] h is the equivalent heat transfer coefficient, T ref This refers to the radiator temperature.

[0013] In the aforementioned method for calculating the periodic temperature fluctuation distribution of an IGBT module, the conduction losses of the IGBT chip and the FWD chip are:

[0014]

[0015] Among them, v ce , v F These are the on-state voltages of the IGBT and FWD, respectively. T i D It is the current flowing through the IGBT and FWD, M T M D It is the duty cycle, which is defined as follows:

[0016]

[0017] Where m is the modulation ratio and ω0 is the angular frequency.

[0018] Switching losses are:

[0019]

[0020] Where f sw It is the equivalent switching frequency, V C K is the average capacitor voltage of the submodule. v This is the voltage correction factor, and Uref is the reference voltage.

[0021] The total loss of a chip is the sum of its conduction loss and its switching loss.

[0022] .

[0023] In the method for calculating the periodic temperature fluctuation distribution of an IGBT module, the total loss expression in frequency domain form is as follows:

[0024]

[0025]

[0026] Where p total P is the instantaneous loss, P0 is the average loss, P k It is the amplitude of the loss after k cycles, φ k Yes, the phase angle of the k-th loss, a k and b k It can be obtained from the following formula:

[0027] .

[0028] In the aforementioned method for calculating the periodic temperature fluctuation distribution of an IGBT module, the periodic steady-state temperature fluctuation distribution is as follows:

[0029] Where T0 is the average temperature, T k Let φ be the amplitude of the k-th temperature fluctuation. k Let θ be the phase angle of the power loss at the kth time. k Let be the phase angle of the k-th temperature response caused by heat conduction.

[0030] In the method for calculating the periodic temperature fluctuation distribution of an IGBT module, the average temperature does not change with instantaneous temperature changes when solving the harmonic temperature response in the frequency domain.

[0031] A system for implementing the method includes:

[0032] The geometric modeling module is used to construct the three-dimensional geometric model of the IGBT module;

[0033] The material parameter setting module is used to input the thermal conductivity, specific heat capacity, and density of each layer of material;

[0034] The frequency domain thermal model construction module is used to establish a frequency domain finite element heat conduction model and apply boundary conditions;

[0035] The frequency domain loss calculation module is used to calculate the periodic losses of IGBTs and FWDs based on operating conditions and perform Fourier decomposition.

[0036] The iterative solution module is used to solve the average temperature field and the frequency domain harmonic temperature response sequentially.

[0037] The time-domain reconstruction module is used to generate the final periodic steady-state temperature fluctuation distribution result through frequency-time domain transformation.

[0038] A computer storage medium including computer instructions that, when run on a computer, cause the computer to perform the method.

[0039] An electronic device, the electronic device comprising:

[0040] Memory, processor, and computer programs stored in memory and executable on the processor, wherein,

[0041] The processor implements the method when executing the program.

[0042] Compared with existing technologies, the present invention has the following advantages: The present invention constructs a heat conduction equation in the frequency domain and a periodic loss input, adopts a two-step iterative strategy of first steady-state average temperature and then frequency domain harmonic disturbance, and combines frequency-time domain transformation technology to achieve efficient and high-precision simulation calculation of the periodic steady-state temperature fluctuation distribution of IGBT modules, overcoming the problems of long time consumption and difficulty in engineering application of traditional transient thermal simulation. Attached Figure Description

[0043] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0044] In the attached diagram:

[0045] Figure 1 This is a schematic diagram of the iterative calculation process of the present invention.

[0046] The present invention will be further explained below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0047] Specific embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0048] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0049] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0050] like Figure 1 As shown, the method for calculating the periodic temperature fluctuation distribution of an IGBT module includes the following steps:

[0051] Step 1: Establish a frequency domain finite element thermal model based on the actual three-dimensional geometric structure and material properties of the IGBT module. The governing equation of the frequency domain finite element thermal model is a steady-state heat conduction equation in frequency domain form. The boundary conditions are Robin boundary conditions to describe the heat transfer relationship between the IGBT module and the heat sink.

[0052] Step 2: Establish the frequency domain loss model of the IGBT module. This involves modeling the conduction and switching losses of the IGBT chip and the FWD chip. The total loss of the chip is the sum of the conduction and switching losses. The frequency domain expression of the periodic loss is obtained using Fourier transform, which includes the average loss, the amplitude and phase angle of each harmonic loss. The amplitude and phase angle of each harmonic loss are used as inputs to the frequency domain thermal model.

[0053] Step 3: Perform iterative calculation. The steady-state heat conduction equation is solved based on the average loss to obtain the average temperature distribution, which is then used as a reference temperature and substituted into the frequency domain loss model. The temperature fluctuation response corresponding to each harmonic is solved in the frequency domain to obtain the amplitude and phase angle of each temperature fluctuation. Through frequency-time domain transformation, the temperature response in the frequency domain is converted into a periodic steady-state temperature fluctuation distribution in the time domain.

[0054] In a preferred embodiment of the method for calculating the periodic temperature fluctuation distribution of an IGBT module, the steady-state heat conduction equation is:

[0055] The equation is the frequency domain heat conduction equation, which is the governing equation of the frequency domain finite element thermal model. The model also includes geometric structure, material parameters, mesh generation, boundary conditions, etc.

[0056] Where ρ is density, c is specific heat capacity, λ is thermal conductivity, ω is frequency, T is temperature, i is the imaginary unit, and xyz is the coordinate system Φ. s The heat source is used. In a preferred embodiment of the method for calculating the periodic temperature fluctuation distribution of an IGBT module, the Robin boundary condition is used to describe the heat transfer relationship between the IGBT module and the heat sink as follows:

[0057] h is the equivalent heat transfer coefficient, T ref Let n be the radiator temperature and n be the normal unit vector.

[0058] In a preferred embodiment of the method for calculating the periodic temperature fluctuation distribution of an IGBT module, the conduction losses of the IGBT chip and the FWD chip are:

[0059]

[0060] Among them, v ce , v F These are the on-state voltages of the IGBT and FWD, respectively. T i D It is the current flowing through the IGBT and FWD, M T M D It is the duty cycle, which is defined as follows:

[0061]

[0062] Where m is the modulation ratio and ω0 is the angular frequency.

[0063] Switching losses are:

[0064]

[0065] Where f sw It is the equivalent switching frequency, V C K is the average capacitor voltage of the submodule. v This is the voltage correction factor, and Uref is the reference voltage.

[0066] The total loss of a chip is the sum of its conduction loss and its switching loss.

[0067] .

[0068] In a preferred embodiment of the method for calculating the periodic temperature fluctuation distribution of an IGBT module, the total loss expression in frequency domain form is as follows:

[0069]

[0070]

[0071] Where p total P is the instantaneous loss, P0 is the average loss, P k It is the amplitude of the loss after k cycles, φ k Yes, the phase angle of the k-th loss, a k and b k It can be obtained from the following formula:

[0072] .

[0073] In a preferred embodiment of the method for calculating the periodic temperature fluctuation distribution of an IGBT module, the periodic steady-state temperature fluctuation distribution is as follows:

[0074] Where T0 is the average temperature, T k Let φ be the amplitude of the k-th temperature fluctuation. k Let θ be the phase angle of the power loss at the kth time. k Let be the phase angle of the k-th temperature response caused by heat conduction.

[0075] In a preferred embodiment of the method for calculating the periodic temperature fluctuation distribution of an IGBT module, the average temperature does not change with instantaneous temperature changes when solving the harmonic temperature response in the frequency domain.

[0076] A system for implementing the method includes:

[0077] The geometric modeling module is used to construct the three-dimensional geometric model of the IGBT module;

[0078] The material parameter setting module is used to input the thermal conductivity, specific heat capacity, and density of each layer of material;

[0079] The frequency domain thermal model construction module is used to establish a frequency domain finite element heat conduction model and apply boundary conditions;

[0080] The frequency domain loss calculation module is used to calculate the periodic losses of IGBTs and FWDs based on operating conditions and perform Fourier decomposition.

[0081] The iterative solution module is used to solve the average temperature field and the frequency domain harmonic temperature response sequentially.

[0082] The time-domain reconstruction module is used to generate the final periodic steady-state temperature fluctuation distribution result through frequency-time domain transformation.

[0083] A computer storage medium including computer instructions that, when run on a computer, cause the computer to perform the method.

[0084] An electronic device, the electronic device comprising:

[0085] Memory, processor, and computer programs stored in memory and executable on the processor, wherein,

[0086] The processor implements the method when executing the program.

[0087] In one embodiment, a three-dimensional geometric model is drawn based on the actual geometry of the IGBT module.

[0088] 2. Set material parameters according to the actual material properties of the IGBT module, including thermal conductivity, specific heat capacity, and density.

[0089] 3. Establish a frequency domain finite element model. The governing equations and boundary conditions are as follows:

[0090] The heat conduction equation in frequency domain form:

[0091]

[0092] The heat transfer interface between the IGBT module and the heat sink can be defined by Robin boundary conditions. For periodic steady-state heat conduction problems, the frequency domain expressions of these boundary conditions are as follows:

[0093]

[0094] h is the equivalent heat transfer coefficient, T ref This refers to the radiator temperature.

[0095] 4. Establish a frequency domain loss model for the IGBT module.

[0096] The conduction losses of IGBT and FWD in an IGBT module can be calculated by the following formula:

[0097]

[0098] Among them, v ce , v F These are the on-state voltages of the IGBT and FWD, respectively. T i D It is the current flowing through the IGBT and FWD, M T M D It is the duty cycle, which is defined as follows:

[0099]

[0100] Where m is the modulation ratio and ω0 is the angular frequency.

[0101] Switching losses can be calculated using the following formula.

[0102]

[0103] Where fsw It is the equivalent switching frequency, V C K is the average capacitor voltage of the submodule. v It is the voltage correction factor, and Uref is the reference voltage given in the datasheet.

[0104] The total loss of a chip is the sum of its conduction loss and its switching loss.

[0105]

[0106] The loss expression in the frequency domain can be obtained through Fourier transform:

[0107]

[0108]

[0109] Where p total P is the instantaneous loss, P0 is the average loss, P k It is the amplitude of the loss after k cycles, φ k Yes, the phase angle of the k-th loss, a k and b k It can be obtained from the following formula:

[0110]

[0111] 5. Iteratively calculate the periodic steady-state temperature fluctuation of the IGBT.

[0112] The calculation process begins with a steady-state study, calculating the average temperature distribution by measuring steady-state heat conduction. In this step, the average power loss P0 is calculated using an average power loss model, and the average temperature T0 is extracted from the average thermal model. Since the junction temperature swing of the IGBT under actual operating conditions is much smaller than the average junction temperature, the influence of the junction temperature swing on the loss can be ignored. Therefore, the harmonic temperature disturbance T can be determined by calculating the heat conduction in the frequency domain. nth In this step, the average temperature T0 is used as a reference value in the frequency domain power loss model. Finally, the temperature field in the frequency domain is converted into a periodic steady-state temperature field in the time domain through the frequency-time domain transformation shown in the following equation.

[0113]

[0114] Where T0 is the average temperature, T k Let φ be the amplitude of the k-th temperature fluctuation. k Let θ be the phase angle of the power loss at the kth time. k Let be the phase angle of the k-th temperature response caused by heat conduction. The iterative calculation process is as follows: Figure 1 As shown.

[0115] Furthermore, this invention significantly improves computational efficiency, breaking through the performance bottleneck of traditional transient simulation. Traditional IGBT module temperature fluctuation simulation typically employs time-domain transient thermal analysis methods, requiring fine-step integration over multiple complete cycles. This results in large computational loads and long processing times, making it difficult to meet the rapid evaluation needs of engineering projects, especially under high-frequency switching or complex modulation conditions. This invention transforms the problem from the time domain to the frequency domain, utilizing the harmonic characteristics of the periodic thermal response. The temperature response of each harmonic order can be obtained through a single frequency-domain finite element method, avoiding point-by-point calculations over long time sequences. Compared to traditional transient simulation, the computational speed can be improved by more than an order of magnitude, making it particularly suitable for reliability assessment scenarios involving multiple operating conditions and long cycles.

[0116] The frequency domain loss model proposed in this invention not only considers the conduction and switching losses of IGBT and FWD chips, but also explicitly expresses the periodic characteristics of the loss through operating parameters such as modulation ratio, angular frequency, and equivalent switching frequency, and obtains the frequency domain input heat source by combining Fourier transform. This method achieves a precise mapping between the electrical behavior (such as PWM modulation and load changes) and thermal response of power electronic systems, ensuring sufficient physical realism of the thermal simulation input source and improving the accuracy of temperature prediction. Since the junction temperature fluctuation amplitude of IGBT is usually much smaller than the average junction temperature (e.g., the swing is tens of degrees Celsius, while the average temperature can reach hundreds of degrees Celsius), this invention reasonably assumes that the impact of temperature fluctuation on semiconductor device losses is negligible, that is, the loss is mainly determined by the average junction temperature. Based on this, a two-stage iterative process is proposed: first, the steady-state thermal field is solved to obtain the average temperature T0T0, and then this is used as a reference temperature for frequency domain loss calculation, and the temperature response of each harmonic is solved. This strategy effectively decouples the nonlinear thermal-electric coupling problem, significantly reduces the solution complexity while ensuring calculation accuracy, and enhances the convergence and robustness of the algorithm. The established frequency-domain finite element thermal model is based on the actual three-dimensional structure of the IGBT module (including multiple layers of materials such as chip, solder layer, substrate, and base plate), and considers the physical parameters of each material such as thermal conductivity, specific heat capacity, and density. It can accurately capture the temperature response amplitude attenuation and phase hysteresis at different locations, and is particularly suitable for analyzing critical reliability areas such as local hot spots on the chip and solder joint fatigue. After obtaining the amplitude Tk and phase angle θk of each temperature harmonic in the frequency domain, combined with the loss phase φk, the junction temperature fluctuation curve T(t) at any given time can be efficiently reconstructed using the frequency-time domain transformation formula. This result can not only be used to extract key reliability indicators such as maximum junction temperature, minimum junction temperature, and junction temperature swing (ΔTj), but also as input data for lifetime prediction models (such as the Coffin-Manson model), providing strong support for the design optimization and condition monitoring of IGBT modules.

[0117] Although embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. Those skilled in the art can make many other forms based on the guidance of this specification and without departing from the scope of protection of the claims of the present invention, and all of these are within the scope of protection of the present invention.

Claims

1. A method for calculating the periodic temperature fluctuation distribution of an IGBT module, characterized in that, Includes the following steps: Step 1: Establish a frequency domain finite element thermal model based on the actual three-dimensional geometric structure and material properties of the IGBT module. The governing equation of the frequency domain finite element thermal model is a steady-state heat conduction equation in frequency domain form. The boundary conditions are Robin boundary conditions to describe the heat transfer relationship between the IGBT module and the heat sink. Step 2: Establish the frequency domain loss model of the IGBT module. This involves modeling the conduction and switching losses of the IGBT chip and the FWD chip. The total loss of the chip is the sum of the conduction and switching losses. The frequency domain expression of the periodic loss is obtained using Fourier transform, which includes the average loss, the amplitude of each harmonic loss, and the phase angle. Step 3: Perform iterative calculation. The steady-state heat conduction equation is solved based on the average loss to obtain the average temperature distribution, which is then used as a reference temperature and substituted into the frequency domain loss model. The temperature fluctuation response corresponding to each harmonic is solved in the frequency domain to obtain the amplitude and phase angle of each temperature fluctuation. Through frequency-time domain transformation, the temperature response in the frequency domain is converted into a periodic steady-state temperature fluctuation distribution in the time domain.

2. The method for calculating the periodic temperature fluctuation distribution of an IGBT module according to claim 1, characterized in that, Preferably, the steady-state heat conduction equation is: Where ρ is density, c is specific heat capacity, λ is thermal conductivity, ω is frequency, T is temperature, i is the imaginary unit, and xyz is the coordinate system Φ. s It is a heat source.

3. The method for calculating the periodic temperature fluctuation distribution of an IGBT module according to claim 1, characterized in that, The Robin boundary conditions are used to describe the heat transfer relationship between the IGBT module and the heat sink: h is the equivalent heat transfer coefficient, T ref This refers to the radiator temperature.

4. The method for calculating the periodic temperature fluctuation distribution of an IGBT module according to claim 1, characterized in that, The conduction losses of the IGBT chip and the FWD chip are, ； Among them, v ce , v F These are the on-state voltages of the IGBT and FWD, respectively. T i D It is the current flowing through the IGBT and FWD, M T M D It is the duty cycle, which is defined as follows: ； Where m is the modulation ratio and ω0 is the angular frequency. Switching losses are: ； Where f sw It is the equivalent switching frequency, V C K is the average capacitor voltage of the submodule. v This is the voltage correction factor, and Uref is the reference voltage. The total loss of a chip is the sum of its conduction loss and its switching loss. 。 5. The method for calculating the periodic temperature fluctuation distribution of an IGBT module according to claim 4, characterized in that, The total loss expression in frequency domain form: ； ； Where p total P is the instantaneous loss, P0 is the average loss, P k It is the amplitude of the loss after k cycles, φ k Yes, the phase angle of the k-th loss, a k and b k It can be obtained from the following formula: 。 6. The method for calculating the periodic temperature fluctuation distribution of an IGBT module according to claim 1, characterized in that, The periodic steady-state temperature fluctuation distribution is as follows ; Where T0 is the average temperature, T k Let φ be the amplitude of the k-th temperature fluctuation. k Let θ be the phase angle of the power loss at the kth time. k Let be the phase angle of the k-th temperature response caused by heat conduction.

7. The method for calculating the periodic temperature fluctuation distribution of an IGBT module according to claim 1, characterized in that, When solving for the harmonic temperature response in the frequency domain, the average temperature does not change with the instantaneous temperature.

8. A system for implementing the method according to any one of claims 1-7, characterized in that, It includes: The geometric modeling module is used to construct the three-dimensional geometric model of the IGBT module; The material parameter setting module is used to input the thermal conductivity, specific heat capacity, and density of each layer of material; The frequency domain thermal model construction module is used to establish a frequency domain finite element heat conduction model and apply boundary conditions; The frequency domain loss calculation module is used to calculate the periodic losses of IGBTs and FWDs based on operating conditions and perform Fourier decomposition. The iterative solution module is used to solve the average temperature field and the frequency domain harmonic temperature response sequentially. The time-domain reconstruction module is used to generate the final periodic steady-state temperature fluctuation distribution result through frequency-time domain transformation.

9. A computer storage medium, characterized in that, The storage medium includes computer instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-7.

10. An electronic device, characterized in that, The electronic device includes: Memory, processor, and computer programs stored in memory and executable on the processor, wherein, When the processor executes the program, it implements the method as described in any one of claims 1-7.

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