Power module coupling thermal resistance calculation method and storage medium

Abstract

The invention discloses a power module coupling thermal resistance calculation method and a storage medium, and the method comprises the steps: obtaining the physical parameters of a power module; simplifying the 3D model for simulation, removing parts irrelevant to the heat transfer direction of the power module, and only reserving parts relevant to the heat transfer direction of the power module; constructing a power module coupling thermal resistance calculation model, which comprises the following steps: generating a simulation grid by using the simplified simulation 3D model, and calculating a substrate Pinfin surface convection heat transfer coefficient according to the generated simulation grid; carrying out steady-state thermal analysis on the convection heat transfer coefficient based on the Pinfin surface, and simulating a heat transfer process changing along with time; iGBT loss and Diode loss are loaded in steady-state thermal analysis, and the highest temperature point coordinates of the IGBT and the highest temperature point coordinates of the Diode are obtained through simulation; simulating and calculating thermal resistance coupled to the Diode by taking the IGBT as a heat source; simulating and calculating the thermal resistance coupled to the IGBT by taking the Diode as a heat source; and fitting the thermal resistances Zth and jfDiode coupled to the Diode and the thermal resistances Zth and jfIGBT coupled to the IGBT to obtain the coupled thermal resistance.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors, and in particular to a method for calculating coupled thermal resistance of a power module and a storage medium. Background Art

[0002] Power modules generally refer to components used in electronic devices to process and convert electrical energy. They can be stand-alone components or modules integrated on a circuit board. Power semiconductor devices: such as IGBT (insulated gate bipolar transistor), MOSFET (metal oxide semiconductor field effect transistor), etc., are used for high-speed switching and power amplification.

[0003] IGBT (insulated gate bipolar transistor) power module is an advanced power semiconductor device that combines the simple gate drive characteristics of MOSFET with the high current and low saturation voltage capabilities of bipolar transistors. IGBT modules are usually packaged by multiple IGBT chips through a specific circuit bridge, and can be directly applied to inverters, UPS uninterruptible power supplies and other equipment. They have the characteristics of energy saving, easy installation and maintenance, and stable heat dissipation. IGBT power modules play a core role in the electric drive system of new energy vehicles. They are mainly responsible for converting the DC power released by the power battery into AC power to make the drive motor work, thereby converting electrical energy into mechanical energy. The standard package form of the IGBT module is a flat rectangular parallelepiped with multiple terminals and pins for different electrical connections. The internal structure of the IGBT module usually includes a parallel-series structure of multiple IGBT chip units, which changes the outflow direction and frequency of the current by fast disconnection, thereby outputting the required AC power.

[0004] The coupled thermal resistance of the IGBT power module refers to the phenomenon that the heat transfer between multiple power devices (such as IGBT chips) inside the module will affect each other due to the close arrangement of multiple power devices (such as IGBT chips). The thermal coupling effect will cause uneven temperature distribution inside the module, affecting the heat dissipation efficiency and overall performance of the module. The coupled thermal resistance is one of the key factors affecting the thermal management of the IGBT module. During the module design and application process, the thermal coupling effect needs to be considered to ensure that the module can operate within a safe temperature range. By optimizing the module layout, selecting appropriate packaging materials and heat dissipation design, the coupled thermal resistance can be reduced and the heat dissipation performance of the module can be improved.

[0005] For example, in an IGBT module, if the distance between two adjacent power devices is close, the heat transfer between them will be enhanced, resulting in a lower coupling thermal resistance. However, if the distance between the devices is too large, the coupling thermal resistance may increase, affecting the overall heat dissipation efficiency.

[0006] With the rapid development of the domestic electric vehicle industry, power modules, as key components of electric vehicles, have also developed significantly. The power density and voltage level have been greatly improved, and the junction temperature has become an increasingly key indicator for monitoring the reliability of power modules. At present, the junction temperature of power modules is mainly monitored by estimating using specific algorithms. In various algorithms, Zth and js are important parameters. Not only the self-thermal resistance of the chip, but also the coupled thermal resistance between chips plays an important role.

[0007] There are two main ways to solve the coupled thermal resistance: calculation and measurement:

[0008] 1. The actual test is difficult and has large errors, and the junction temperature estimation is difficult. However, the solution of measuring the coupled thermal resistance is difficult to implement technically. The measurement of the junction temperature itself is difficult, and the error of fitting the coupled thermal resistance after measuring the temperature change curve is even higher.

[0009] 2. Calculating the coupled thermal resistance by the heat diffusion angle is a common method. However, the method of calculating the coupled thermal resistance by the heat diffusion angle simplifies the process of heat transfer downward from the chip, which is quite different from the actual heat transfer process, thus introducing a large error and having little reference value.

[0010] Chinese patent CN116298749A uses actual measurement to obtain the coupled thermal resistance, with device 1 as the heat source and device 2 as the device to be measured, and uses the electrical parameter measurement method to obtain the temperature response curve of device 2 to device 1 as the heat source, and uses this curve to fit the coupled thermal resistance of device 1 to device 2. This measurement method has a large error, and there is a delay in the temperature response of device 2 to device 1 when it is a heat source, which will introduce a large error in fitting.

[0011] In summary, there is an urgent need for a solution that can quickly and accurately obtain the coupled thermal resistance of the power module. Summary of the invention

[0012] A series of simplified concepts are introduced in the Summary of the Invention, which are all simplifications of the prior art in the field, and will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention of the present invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0013] The technical problem to be solved by the present invention is to provide a calculation method and a storage medium capable of quickly and accurately obtaining the coupled thermal resistance of a power module.

[0014] In order to solve the above technical problems, the present invention provides a method for calculating the coupled thermal resistance of a power module, comprising the following steps:

[0015] S1, obtaining the physical parameters of the power module;

[0016] S2, simplifying the 3D model for simulation, removing components irrelevant to the heat transfer direction of the power module, and only retaining components relevant to the heat transfer direction of the power module;

[0017] S3, constructing a coupled thermal resistance calculation model for the power module, including: generating a simulation grid from the simplified simulation 3D model, and calculating the surface flow heat transfer coefficient of the substrate Pinfin according to the generated simulation grid;

[0018] S4, steady-state thermal analysis based on Pinfin surface flow heat transfer coefficient and simulation of heat transfer process changing with time;

[0019] S5, load IGBT loss and diode loss in steady-state thermal analysis, and obtain the coordinates of the highest temperature points of IGBT and diode respectively through simulation;

[0020] S6, using IGBT as heat source to simulate and calculate the thermal resistance coupled to the diode;

[0021] Taking diode as heat source, simulate and calculate the thermal resistance coupled to IGBT;

[0022] S7, the thermal resistance Z coupled to the diode th,jf_Diode and the thermal resistance Z coupled to the IGBT th,jf_IGBT Fitting is performed to obtain the coupled thermal resistance.

[0023] Preferably, the power module coupled thermal resistance calculation method is further improved, and the components unrelated to the heat transfer direction of the power module include: a frame, bonding wires on the chip and silicone gel;

[0024] Components related to the heat transfer direction of the power module include: chip, chip lower layer solder, DBC lower layer solder, DBC copper layer, substrate, coolant and heat dissipation water channel.

[0025] The 3D model for simulation is any one of the prior art.

[0026] Preferably, the power module coupled thermal resistance calculation method is further improved, and the implementation step S3 includes:

[0027] The simplified simulation 3D model is used to generate a simulation mesh through Ansys Workbench Mesh, and the generated simulation mesh is used to calculate the surface heat transfer coefficient of the substrate Pinfin through Ansys CFX.

[0028] Preferably, the power module coupled thermal resistance calculation method is further improved, and the implementation step S4 includes:

[0029] The Pinfin surface flow heat transfer coefficient is imported into Ansys Steady-State Thermal for steady-state thermal analysis, and the Pinfin surface flow heat transfer coefficient is imported into Transient Thermal to simulate the heat transfer process that changes with time.

[0030] Preferably, the power module coupled thermal resistance calculation method is further improved, and the implementation step S5 includes:

[0031] Obtain E under given driving conditions by double pulse test on , Eo ff 、E rev ;

[0032] E on :IGBT turn-on loss;

[0033] Eoff: IGBT turn-off loss;

[0034] Erev: Diode reverse recovery loss;

[0035] Use the following formula to calculate the IGBT loss P IGBT and the diode loss P Diode :

[0036] P IGBT =(E on +E cond +E off )*f sw ;

[0037] P Diode =(E rev +E cond )*f sw .

[0038] fsw: IGBT switching frequency.

[0039] Preferably, the power module coupled thermal resistance calculation method is further improved, and the implementation step S6 includes:

[0040] Use the calculated maximum temperature coordinates of IGBT and Diode to establish the coordinate system, insert the temperature probe, and set the initial temperature to T0;

[0041] Using IGBT or Diode as the heat source, simulate and obtain the response T of the temperature probe over time (0-10S) j (t);

[0042] The coupled thermal resistance Z is calculated using the following formula: th,jf , Z th,jf =(T j (t)-T0) / P.

[0043] Preferably, the power module coupled thermal resistance calculation method is further improved, and the implementation step S7 includes:

[0044] Diode coupling thermal resistance Z th,jf_Diode or IGBT coupling thermal resistance Z th,jf_IGBT Import into Matlab;

[0045] The fourth-order function of coupled thermal resistance is obtained by curve fitting.

[0046] In order to solve the above technical problem, the present invention provides a computer-readable storage medium, which stores a computer program therein. When the computer program is executed, it is used to implement the steps in any one of the above-mentioned methods for calculating the coupled thermal resistance of a power module.

[0047] The present invention proposes to use the finite element analysis method to find the coordinates of the highest temperature point under the IGBT+Diode loss condition for the power module; when solving the coupled thermal resistance, only device 1 is used as the heat source to obtain the temperature response curve of the coordinates of the highest temperature point found by device 2; after obtaining the corresponding curve, the coupled thermal resistance is fitted, and vice versa. The present invention adopts a simulation method, the initial parameter setting is highly adjustable, there is no temperature data sampling delay, and the error is low; the highest temperature point coordinate method is used for solving, the temperature value is fast and accurate, and the difficulty of obtaining the temperature response curve of the heat source for the measured point is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The drawings of the present invention are intended to illustrate the general characteristics of the methods, structures and / or materials used in specific exemplary embodiments of the present invention, and to supplement the description in the specification. However, the drawings of the present invention are schematic diagrams not drawn to scale, and thus may not accurately reflect the precise structure or performance characteristics of any given embodiment, and the drawings of the present invention should not be interpreted as limiting or restricting the range of values ​​or properties covered by the exemplary embodiments of the present invention. The present invention is further described in detail below in conjunction with the drawings and specific embodiments:

[0049] Figure 1 It is a schematic diagram of the process framework of the power module coupled thermal resistance calculation method of the present invention. DETAILED DESCRIPTION

[0050] The following is an explanation of the embodiments of the present invention by specific specific embodiments, and those skilled in the art can fully understand other advantages and technical effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through different specific embodiments, and the details in this specification can also be applied based on different viewpoints, and various modifications or changes can be made without deviating from the general design concept of the invention. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. The following exemplary embodiments of the present invention can be implemented in a variety of different forms and should not be interpreted as being limited to the specific embodiments described here. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the technical solutions of these exemplary specific embodiments to those skilled in the art. It should be understood that when an element is referred to as "connected" or "coupled" to another element, the element can be directly connected or coupled to another element, or there can be an intermediate element. The difference is that when an element is referred to as "directly connected" or "directly coupled" to another element, there is no intermediate element. In all the drawings, the same reference numerals always represent the same elements.

[0051] First embodiment;

[0052] refer to Figure 1 As shown, the method for calculating the coupled thermal resistance of a power module provided by the present invention comprises the following steps:

[0053] S1, obtaining the physical parameters of the power module;

[0054] S2, simplifying the 3D model for simulation, removing components irrelevant to the heat transfer direction of the power module, and retaining only components relevant to the heat transfer direction of the power module; the 3D model for simulation is any one of the prior art;

[0055] For example, a three-dimensional simulation model of a semiconductor device is established through the COMSOL Multiphysics simulation tool;

[0056] Combine PSpice and COMSOL for multi-physics transient modeling to obtain a three-dimensional simulation model of semiconductor devices;

[0057] Establish a three-dimensional simulation model of semiconductor devices through Ansys simulation;

[0058] Wolfspeed simulates ECAD symbols, package drawings and semiconductor device 3D simulation models;

[0059] Among them, the components not related to the heat transfer direction of the power module include: frame, bonding wires on the chip and silicone gel;

[0060] Components related to the heat transfer direction of the power module include: chip, chip lower layer solder, DBC lower layer solder, DBC copper layer, substrate, coolant and heat dissipation water channel.

[0061] S3, constructing a coupled thermal resistance calculation model for the power module, including: using the simplified simulation 3D model to generate a simulation mesh through Ansys Workbench Mesh, and using the generated simulation mesh to calculate the surface flow heat transfer coefficient of the substrate Pinfin through Ansys CFX.

[0062] S4, steady-state thermal analysis based on Pinfin surface flow heat transfer coefficient and simulation of heat transfer process changing with time;

[0063] For example, the Pinfin surface flow heat transfer coefficient is imported into Ansys Steady-State Thermal for steady-state thermal analysis, and the Pinfin surface flow heat transfer coefficient is imported into Transient Thermal to simulate the heat transfer process that changes with time.

[0064] Ansys Steady-State Thermal is a module in the Ansys Workbench platform that is specifically designed to perform steady-state thermal analysis. This type of analysis is suitable for evaluating the impact of heat transfer on system performance when there is no time variation.

[0065] Ansys Transient Thermal analysis is a tool for simulating time-dependent heat transfer processes. This analysis is critical for evaluating the thermal behavior of a system under non-steady-state conditions, such as equipment at startup, shutdown, or under varying load conditions.

[0066] S5, load IGBT loss and diode loss in steady-state thermal analysis, and obtain the coordinates of the highest temperature points of IGBT and diode respectively through simulation;

[0067] For example, the E under given driving conditions is obtained by double pulse testing. on , Eo ff 、E rev ;

[0068] E on :IGBT turn-on loss;

[0069] Eoff: IGBT turn-off loss;

[0070] Erev: Diode reverse recovery loss;

[0071] Use the following formula to calculate the IGBT loss P IGBT and the diode loss P Diode :

[0072] P IGBT =(E on +E cond +E off )*f sw ;

[0073] P Diode =(E rev +E cond )*f sw .

[0074] fsw: IGBT switching frequency.

[0075] S6, using IGBT as heat source to simulate and calculate the thermal resistance coupled to the diode;

[0076] Taking diode as heat source, simulate and calculate the thermal resistance coupled to IGBT;

[0077] Use the calculated maximum temperature coordinates of IGBT and Diode to establish a coordinate system in Ansys Transient Thermal, insert a temperature probe Probe in Solution, and set the initial temperature to T0;

[0078] Take IGBT or Diode as the heat source and simulate the response T of the temperature probe Probe over time (for example, 0-10S). j (t);

[0079] The coupled thermal resistance Z is calculated using the following formula: th,jf , Z th,jf =(T j (t)-T0) / P.

[0080] S7, the thermal resistance Z coupled to the diode th,jf_Diode and the thermal resistance Z coupled to the IGBT th,jf_IGBT Fitting is performed to obtain the coupled thermal resistance, including:

[0081] Diode coupling thermal resistance Z th,jf_Diode or IGBT coupling thermal resistance Z th,jf_IGBT Import into Matlab;

[0082] The fourth-order function of coupled thermal resistance is obtained by curve fitting.

[0083] Second embodiment;

[0084] The present invention provides a computer-readable storage medium, which stores a computer program therein. When the computer program is executed, it is used to implement the steps in the method for calculating the coupled thermal resistance of a power module described in the first embodiment.

[0085] The computer-readable medium includes permanent and non-permanent, removable and non-removable media and can be implemented by any method or technology to store information. Information can be computer-readable instructions, data structures, modules of programs or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include non-transitory media such as modulated data signals and carrier waves.

[0086] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. It will also be understood that, unless expressly defined herein, terms such as those defined in general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not interpreted in an ideal or overly formal sense.

[0087] The present invention has been described in detail above through specific implementation modes and embodiments, but these do not constitute limitations of the present invention. Without departing from the principles of the present invention, those skilled in the art may also make many variations and improvements, which should also be regarded as the protection scope of the present invention.

Claims

1. A method for calculating coupled thermal resistance of a power module, characterized in that: The following steps are involved: S1, obtaining the physical parameters of the power module; S2, simplifying the 3D model for simulation, removing components irrelevant to the heat transfer direction of the power module, and only retaining components relevant to the heat transfer direction of the power module; S3, constructing a coupled thermal resistance calculation model for the power module, including: generating a simulation grid from the simplified simulation 3D model, and calculating the surface flow heat transfer coefficient of the substrate Pinfin according to the generated simulation grid; S4, steady-state thermal analysis based on Pinfin surface flow heat transfer coefficient and simulation of heat transfer process changing with time; S5, load IGBT loss and diode loss in steady-state thermal analysis, and obtain the coordinates of the highest temperature points of IGBT and diode respectively through simulation; S6, using IGBT as heat source to simulate and calculate the thermal resistance coupled to the diode; Taking diode as heat source, simulate and calculate the thermal resistance coupled to IGBT; S7, the thermal resistance Z coupled to the diode th,jf_Diode and the thermal resistance Z coupled to the IGBT th,jf_IGBT Fitting is performed to obtain the coupled thermal resistance.

2. The method for calculating coupled thermal resistance of a power module according to claim 1, wherein: Components not related to the heat transfer direction of the power module include: frame, bonding wires on the chip and silicone gel; Components related to the heat transfer direction of the power module include: chip, chip lower layer solder, DBC lower layer solder, DBC copper layer, substrate, coolant and heat dissipation water channel.

3. The method for calculating the coupled thermal resistance of a power module according to claim 1, wherein: The implementation step S3 includes: The simplified simulation 3D model is used to generate a simulation mesh through Ansys Workbench Mesh, and the generated simulation mesh is used to calculate the surface heat transfer coefficient of the substrate Pinfin through Ansys CFX. a. Import the calculated Pinfin convection heat transfer coefficient into Ansys Steady-State Thermal and Ansys Transient Thermal.

4. The method for calculating the coupled thermal resistance of a power module according to claim 1, wherein: The implementation step S4 includes: The Pinfin surface flow heat transfer coefficient is imported into Ansys Steady-State Thermal for steady-state thermal analysis, and the Pinfin surface flow heat transfer coefficient is imported into Transient Thermal to simulate the heat transfer process that changes with time.

5. The method for calculating coupled thermal resistance of a power module according to claim 1, wherein: The implementation step S5 includes: Obtain E under given driving conditions by double pulse test on , Eo ff 、E rev ; E on :IGBT turn-on loss; Eoff: IGBT turn-off loss; Erev: Diode reverse recovery loss; Use the following formula to calculate the IGBT loss P IGBT and the diode loss P Diode : P IGBT =(And on +E cond +E off )*f sw ; Q Diode =(E rev +E cond )*f sw . fsw: IGBT switching frequency.

6. The method for calculating the coupled thermal resistance of a power module according to claim 5, characterized in that: The implementation step S6 includes: Use the calculated maximum temperature coordinates of IGBT and Diode to establish the coordinate system, insert the temperature probe, and set the initial temperature to T0; Using IGBT or Diode as heat source, simulate the response of temperature probe over time. j (t); The coupled thermal resistance Z is calculated using the following formula: th,jf , Z th,jf =(T j (t)-T0) / P.

7. The method for calculating the coupled thermal resistance of a power module according to claim 6, wherein: The implementation step S7 includes: The diode coupling thermal resistance Z th,jf_Diode or IGBT coupling thermal resistance Z th,jf_IGBT Import into Matlab; The fourth-order function of coupled thermal resistance is obtained by curve fitting.

8. A computer-readable storage medium, characterized in that: A computer program is stored therein, and when the computer program is executed, it is used to implement the steps in the power module coupling thermal resistance calculation method according to any one of claims 1-2.

Images