Frequency domain modeling method and application of thermal flow characteristics of power semiconductor devices

Abstract

The present invention provides a frequency domain modeling method and application of the thermal flow characteristics of a power semiconductor device. Based on the amplitude-frequency characteristics of the outflow heat flow of the power semiconductor device in the frequency domain, a multi-order low-pass filter model containing three characteristic frequencies is established, and the low-pass filter model is used to construct a frequency domain model of the output heat flow of the power semiconductor device, so as to realize the simulation and application of the thermal flow characteristics of the power semiconductor device. Among them, the amplitude-frequency characteristics of the low-pass filter should be as consistent as possible with the amplitude-frequency characteristics of the outflow heat flow of the device, and the characteristic frequency of the low-pass filter is 3. The total order of the low-pass filter is consistent with the number of material layers inside the power semiconductor device. At the same time, a corresponding terminal and medium are provided. The present invention can accurately characterize the thermal flow characteristics of the power semiconductor device and improve the prediction accuracy of the thermal characteristics and aging state of the power semiconductor device under working conditions.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a frequency domain modeling method and application of thermal flow characteristics of a power semiconductor device, as well as a corresponding terminal and a computer-readable storage medium. Background Art

[0002] Whether the thermal characteristics of power semiconductor devices in actual applications can be accurately predicted is an important basis for improving the reliability of power electronic systems. In recent years, various lumped thermal network models have emerged to characterize the temperature characteristics of power semiconductor devices, but the heat flow characteristics of power semiconductor devices have rarely received attention because heat flow is more complex than temperature characteristics and difficult to characterize with models. However, heat flow is a very important dimension in describing the thermal characteristics of power semiconductor devices. Accurately characterizing it can greatly improve the prediction accuracy of the thermal characteristics of power semiconductor devices in actual applications.

[0003] After searching, we found:

[0004] The Chinese invention patent "A method and system for determining thermal characteristic parameters of a power semiconductor device" with the authorization number CN107908875B first uses the Richardson-Lucy algorithm to process the thermal transient response signal of the measured power semiconductor device to obtain the thermal characteristic parameters of the Foster network model; secondly, based on the thermal characteristic parameters of the Foster network model, the thermal characteristic parameters of the Kaul network model are calculated using Mathematica software, and the thermal characteristic parameters of the Kaul network model are accumulated and derivatized according to the order to obtain the integral structure function and the differential structure function; finally, the thermal resistance parameters and thermal capacitance parameters of the measured power semiconductor device are calculated based on the integral structure function and the differential structure function. This method and system still have the following problems:

[0005] This method and system only determine the parameters of the existing lumped thermal network model. However, some existing lumped models, whether Kaul or Foster, have their limitations, that is, they only describe the temperature characteristics but cannot accurately characterize the heat flow characteristics.

[0006] At present, no description or report of similar technology to the present invention has been found, and similar information at home and abroad has not been collected yet. Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention provides a frequency domain modeling method and application of thermal flow characteristics of a power semiconductor device, and also provides a corresponding terminal and a computer-readable storage medium.

[0008] According to one aspect of the present invention, a frequency domain modeling method for thermal flow characteristics of a power semiconductor device is provided, comprising:

[0009] Based on the amplitude-frequency characteristics of the output heat flux of power semiconductor devices in the frequency domain, a multi-order low-pass filter model with three characteristic frequencies is established; where:

[0010] The amplitude-frequency characteristics of the low-pass filter are consistent with those of the heat flux flowing out of the device, and the low-pass filter has three characteristic frequencies; the total order of the low-pass filter is the same as the number of internal material layers of the power semiconductor device; according to the bandwidth frequency of the amplitude-frequency gain of the heat flux between adjacent two layers of materials inside the power semiconductor device, the amplitude-frequency characteristics of multiple heat fluxes inside the power semiconductor device are divided into three groups, and the order of the low-pass filter at each characteristic frequency is the same as the number of amplitude-frequency characteristics of the heat flux inside the power semiconductor device included in each group, and only one characteristic frequency is used for the heat flux inside the power semiconductor device included in each group, then the low-pass filter model G LPF (s) is:

[0011]

[0012] In the formula, s is the s-domain variable after Laplace transform, f1, f2 and f3 are the three characteristic frequencies of the low-pass filter, and satisfy f1 < f2 < f3; a, b and c are the orders at each characteristic frequency of the low-pass filter; the three characteristic frequencies of the low-pass filter correspond to the amplitude-frequency characteristics of the output heat flux in the low-frequency band, medium-frequency band and high-frequency band of the power semiconductor device from small to large; the orders at each characteristic frequency of the low-pass filter are determined according to the grouping results of the amplitude-frequency characteristics of the heat flux inside the power semiconductor device;

[0013] Determine the three characteristic frequencies f1, f2 and f3 of the low-pass filter to complete the frequency-domain modeling of the heat flux characteristics of the power semiconductor device.

[0014] Preferably, the power semiconductor device includes: silicon-based and non-silicon-based IGBTs, MOSFETs, transistors, thyristors and diodes, the packaging forms of the power semiconductor device include: single-tube, welded and press-fit structures, and the heat sinks of the power semiconductor device include: air-cooled or water-cooled heat dissipation structures containing thermal grease and air-cooled or water-cooled heat dissipation structures in direct contact without thermal grease.

[0015] Preferably, the method for constructing the low-pass filter model includes:

[0016] Using finite element simulation software, establish the geometric model of the power semiconductor device and perform mesh generation, and perform frequency-domain analysis and data processing on the temperature and heat flux signals in the geometric model to obtain the power semiconductor device model;

[0017] Based on the power semiconductor model, extract the internal heat flow characteristics of the power semiconductor device, and use the frequency domain simulation tool in the finite element simulation software to obtain the frequency domain amplitude gain of the heat flow of adjacent material layers inside the power semiconductor device;

[0018] The number of low-pass filter layers is obtained according to the number of material layers of the power semiconductor device, and then the multiple heat flow amplitude-frequency characteristics inside the power semiconductor device are divided into three groups according to the bandwidth frequency at which the amplitude-frequency gain of the heat flow between two adjacent layers of material inside the power semiconductor device is attenuated to -3dB. The heat flow amplitude-frequency characteristics in each group are represented by a characteristic frequency f1, f2 and f3 respectively, so as to obtain a multi-order low-pass filter model containing three characteristic frequencies.

[0019] Preferably, the orders of the low-pass filter at each characteristic frequency are: a=1, b=3, c=3.

[0020] Preferably, the three characteristic frequencies f1, f2 and f3 of the low-pass filter are determined by any one of the following methods:

[0021] -Simulation-based methods;

[0022] -Methods based on experimental measurements.

[0023] Preferably, the simulation-based method comprises:

[0024] The time domain output heat flow characteristics under simulation are extracted by setting a heat flow probe at the output position (i.e., the position where the heat flows out of the power semiconductor device along the direction of heat flow);

[0025] According to the low-pass filter model G LPF (s) Obtain an output heat flow expression, use the output heat flow expression to approximate the time-domain output heat flow characteristics under simulation, and obtain the three characteristic frequencies f1, f2 and f3 of the low-pass filter.

[0026] Preferably, the experimental measurement method comprises:

[0027] Use a temperature sensor or a heat flow sensor to measure the time domain output heat flow characteristics of the output position under simulation (i.e., the position where the heat flows out of the power semiconductor device along the direction of heat flow);

[0028] According to the low-pass filter model G LPF (s) Obtain an output heat flow expression, use the output heat flow expression to approximate the time-domain output heat flow characteristics under simulation, and obtain the three characteristic frequencies f1, f2 and f3 of the low-pass filter.

[0029] Preferably, the time-domain output heat flux characteristics of the output position under the simulation measured by a heat flux sensor are obtained by directly measuring the heat flux curve at the output position of the power semiconductor; the time-domain output heat flux characteristics of the output position under the simulation measured by a temperature sensor are estimated by placing temperature sensors on the shell surface and the heat sink surface directly below the output position of the power semiconductor, and then dividing the time-domain temperature difference step response curve of the shell minus the heat sink by the steady-state thermal resistance of the shell minus the heat sink.

[0030] Preferably, the use of the output heat flow expression to approximate the time-domain output heat flow characteristics under simulation to obtain the three characteristic frequencies f1, f2 and f3 of the low-pass filter includes:

[0031] According to the output heat flow expression, the function is approximated by using the curve fitting method to obtain the power semiconductor output heat flow P out The time domain step response fitting formula of (t) is:

[0032]

[0033] Where P in is the magnitude of the applied step loss, is the inverse Laplace transform, G LPF (s) is a low-pass filter model;

[0034] According to the time domain step response fitting formula of the power semiconductor output heat flow, the three characteristic frequencies f1, f2 and f3 of the low-pass filter are extracted.

[0035] Preferably, the method further comprises:

[0036] The heat flow characteristics of the power semiconductor device are described by the characteristic frequencies f1, f2 and f3; wherein:

[0037] The characteristic frequencies f1, f2 and f3 are combined with the lumped model to obtain transient characteristics of heat flow and temperature of the power semiconductor device, thereby achieving a description of the thermal characteristics of the power semiconductor device.

[0038] According to another aspect of the present invention, a device health status monitoring method based on the thermal flow characteristics of a power semiconductor device is provided, and the frequency domain modeling method of the thermal flow characteristics of a power semiconductor device as described in any of the above items is adopted. According to the frequency domain model of the thermal flow characteristics of the power semiconductor device, three characteristic frequencies f1, f2 and f3 are extracted, and compared with the characteristic frequencies in a healthy state. When the frequency change rate of any one or more of the characteristic frequencies f1, f2 and f3 reaches a set threshold, it is judged that aging has occurred in a group of material layers corresponding to the characteristic frequencies, and the monitoring of the device health status is completed.

[0039] According to a third aspect of the present invention, there is provided a terminal comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the terminal can be used to execute any one of the frequency domain modeling methods described above, or the device health status monitoring method described above.

[0040] According to a fourth aspect of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, can be used to execute any of the frequency domain modeling methods described above, or the device health status monitoring method described above.

[0041] Due to the adoption of the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art:

[0042] The frequency domain modeling method, application, terminal and medium of the thermal flow characteristics of a power semiconductor device provided by the present invention can accurately simulate and characterize the thermal flow characteristics of a power semiconductor device and improve the prediction accuracy of the thermal characteristics under working conditions of the power semiconductor device. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0044] Figure 1 The flowchart is a method for frequency domain modeling of thermal flow characteristics of a power semiconductor device in one embodiment of the present invention.

[0045] Figure 2 The flowchart is a method for frequency domain modeling of thermal flow characteristics of a power semiconductor device in a preferred embodiment of the present invention.

[0046] Figure 3 It is a schematic diagram of a power semiconductor device model based on finite element simulation software in a preferred embodiment of the present invention.

[0047] Figure 4 This is a frequency domain amplitude gain diagram of heat flux of adjacent layers in a preferred embodiment of the present invention.

[0048] Figure 5 It is a schematic diagram of a low-pass filter model obtained based on the grouping result in a preferred embodiment of the present invention.

[0049] Figure 6 It is a schematic diagram of simulation results of thermal flow characteristics of a power semiconductor device in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0050] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0051] Figure 1 It is a flowchart of a frequency-domain modeling method for the heat flow characteristics of a power semiconductor device provided by an embodiment of the present invention.

[0052] As Figure 1 shown, the frequency-domain modeling method for the heat flow characteristics of the power semiconductor device provided by this embodiment may include the following steps:

[0053] S100, based on the amplitude-frequency characteristics presented by the output heat flow of the power semiconductor device in the frequency domain, establish a multi-order low-pass filter model including 3 characteristic frequencies; where:

[0054] The amplitude-frequency characteristics of the low-pass filter are consistent with the amplitude-frequency characteristics of the heat flow flowing out of the device, and the characteristic frequencies of the low-pass filter are 3; the total order of the low-pass filter is consistent with the number of internal material layers of the power semiconductor device; according to the bandwidth frequency of the amplitude-frequency gain of the heat flow between two adjacent layers of materials inside the power semiconductor device, the multiple heat flow amplitude-frequency characteristics inside the power semiconductor device are divided into 3 groups, and the order of the low-pass filter at each characteristic frequency is the same as the number of heat flow amplitude-frequency characteristics inside the power semiconductor device included in each group, and only 1 characteristic frequency is used for the heat flow inside the power semiconductor device included in each group, then the low-pass filter model G LPF (s) is:

[0055]

[0056] In the formula, s is the s-domain variable after Laplace transform, f1, f2 and f3 are the 3 characteristic frequencies of the low-pass filter, and satisfy f1 < f2 < f3; a, b and c are the orders at each characteristic frequency of the low-pass filter; the 3 characteristic frequencies of the low-pass filter correspond to the amplitude-frequency characteristics of the output heat flow in the low-frequency band, medium-frequency band and high-frequency band of the power semiconductor device from small to large; the orders at each characteristic frequency of the low-pass filter are determined according to the grouping result of the heat flow amplitude-frequency characteristics inside the power semiconductor device;

[0057] S200, determine the 3 characteristic frequencies f1, f2 and f3 of the low-pass filter to complete the frequency-domain modeling of the heat flow characteristics of the power semiconductor device.

[0058] In this embodiment, as a preferred embodiment, the power semiconductor device may include: silicon-based and non-silicon-based IGBTs, MOSFETs, transistors, thyristors and diodes; the packaging forms of the power semiconductor devices include: single tube, welding and crimping structures; the heat sinks of the power semiconductor devices include: air-cooled or water-cooled heat dissipation structures containing thermal grease and air-cooled or water-cooled heat dissipation structures without direct contact with thermal grease.

[0059] In S100 of this embodiment, as a preferred embodiment, the method for constructing a low-pass filter model may include the following steps:

[0060] S101, using finite element simulation software, establishing a geometric model of a power semiconductor device and performing mesh generation, performing frequency domain analysis and data processing on temperature and heat flow signals in the geometric model, and obtaining a power semiconductor device model;

[0061] S102, based on the power semiconductor model, extracting the internal heat flow characteristics of the power semiconductor device, and using the frequency domain simulation tool in the finite element simulation software to obtain the frequency domain amplitude gain of the heat flow of adjacent material layers inside the power semiconductor device;

[0062] S103, obtaining the number of low-pass filter layers according to the number of material layers of the power semiconductor device, and then dividing the multiple heat flow amplitude-frequency characteristics inside the power semiconductor device into three groups according to the bandwidth frequency attenuated to -3dB by the amplitude-frequency gain of the heat flow between two adjacent layers of materials inside the power semiconductor device. The heat flow amplitude-frequency characteristics in each group are represented by a characteristic frequency f1, f2 and f3 respectively, that is, a multi-order low-pass filter model containing three characteristic frequencies is obtained.

[0063] In S100 of this embodiment, as a preferred embodiment, preferably, the orders of the low-pass filter at each characteristic frequency are: a=1, b=3, c=3.

[0064] In S200 of this embodiment, as a preferred embodiment, the three characteristic frequencies f1, f2 and f3 of the low-pass filter can be determined by any of the following methods:

[0065] -Simulation-based methods;

[0066] -Methods based on experimental measurements.

[0067] Further, as a preferred embodiment, the simulation-based method may include the following steps:

[0068] S2011, extracting the time-domain output heat flow characteristics under simulation by setting a heat flow probe at an output position (i.e., a position where heat flows out of the power semiconductor device along a heat flow direction);

[0069] S2012, according to the low-pass filter model GLPF (s) The output heat flow expression is obtained, and the output heat flow expression is used to approximate the time domain output heat flow characteristics under simulation to obtain the three characteristic frequencies f1, f2 and f3 of the low-pass filter.

[0070] Furthermore, as a preferred embodiment, the experimental measurement method may include the following steps:

[0071] S2021, using a temperature sensor or a heat flow sensor to measure the time domain output heat flow characteristics of an output position (i.e., a position where heat flows out of the power semiconductor device along a direction of heat flow) under simulation;

[0072] S2022, according to the low-pass filter model G LPF (s) The output heat flow expression is obtained, and the output heat flow expression is used to approximate the time domain output heat flow characteristics under simulation to obtain the three characteristic frequencies f1, f2 and f3 of the low-pass filter.

[0073] In S2021 of this embodiment, as a preferred embodiment, a heat flux sensor is used to measure the time-domain output heat flux characteristics of the output position under simulation, which is obtained by directly measuring the heat flux curve at the output position of the power semiconductor; a temperature sensor is used to measure the time-domain output heat flux characteristics of the output position under simulation, which is obtained by placing temperature sensors on the shell surface and the heat sink surface directly below the output position of the power semiconductor, respectively, and then estimating the time-domain temperature difference step response curve of the shell minus the heat sink divided by the steady-state thermal resistance of the shell minus the heat sink.

[0074] In S2022 of this embodiment, as a preferred embodiment, as a preferred embodiment, using the output heat flow expression to approximate the time domain output heat flow characteristics under simulation, to obtain three characteristic frequencies f1, f2 and f3 of the low-pass filter, can include the following steps:

[0075] S20221, according to the output heat flow expression, the function is approximated by using the curve fitting method to obtain the power semiconductor output heat flow P out The time domain step response fitting formula of (t) is:

[0076]

[0077] Where P in is the magnitude of the applied step loss, is the inverse Laplace transform, G LPF (s) is a low-pass filter model;

[0078] S20222, according to the time domain step response fitting formula of the power semiconductor output heat flow, the three characteristic frequencies f1, f2 and f3 of the low-pass filter are extracted.

[0079] In this embodiment, as a preferred embodiment, the method may further include the following steps:

[0080] S300, describing the heat flow characteristics of the power semiconductor device through characteristic frequencies f1, f2 and f3; wherein:

[0081] By combining the characteristic frequencies f1, f2 and f3 with the lumped model, the transient characteristics of the heat flow and temperature of the power semiconductor device are obtained, thereby realizing the description of the thermal characteristics of the power semiconductor device.

[0082] Figure 2 A flowchart of a frequency domain modeling method for thermal flow characteristics of a power semiconductor device provided in a preferred embodiment of the present invention.

[0083] like Figure 2 As shown, the frequency domain modeling method of the thermal flow characteristics of a power semiconductor device provided in this preferred embodiment mainly includes the following steps:

[0084] S1, establish a finite element simulation model to obtain the frequency domain characteristics of thermal flow;

[0085] S2, based on the frequency domain characteristics of heat flow, a low-pass filter model is constructed;

[0086] S3, based on the low-pass filter model, construct the output heat flow expression of the power semiconductor device;

[0087] S4, according to the constructed output heat flow expression of the power semiconductor device, the characteristic frequency of the low-pass filter model is determined to complete the frequency domain modeling of the heat flow characteristics of the power semiconductor device.

[0088] The frequency domain modeling method for thermal flow characteristics of a power semiconductor device provided in the preferred embodiment further includes the following steps:

[0089] S5, describes the heat flow characteristics of power semiconductor devices through the characteristic frequency of the low-pass filter model.

[0090] Figure 3 FIG. 1 is a schematic diagram of a power semiconductor device model based on finite element simulation software provided in a preferred embodiment of the present invention. Figure 3 As shown in the figure, the power semiconductor device model is an IGBT model established using COMSOL software, including an IGBT chip layer, a chip solder layer, an upper copper layer, a ceramic layer, a lower copper layer, a substrate solder layer, and a substrate, a total of seven layers. The main parameters of the module include the material, thickness, density, thermal conductivity, heat capacity, and thermal resistance of each layer.

[0091] Figure 4 FIG. 1 is a frequency domain amplitude gain diagram of heat flow in adjacent layers of a power semiconductor device in a preferred embodiment of the present invention. Figure 4As shown in FIG. 1 , the heat flow characteristics of the power semiconductor device can be divided into three groups according to the gain characteristics of adjacent layers. The first group includes one layer of material, the second group includes three layers of material, and the third group includes three layers of material. The grouping result indicates that the frequency domain heat flow characteristics of the corresponding layers in the same group are similar, and the heat flow characteristics of each group are represented by a parameter.

[0092] Figure 5 The figure is a schematic diagram of a low-pass filter model obtained based on the grouping result in a preferred embodiment of the present invention. Since the power semiconductor device in the preferred embodiment includes a seven-layer structure including an IGBT chip layer, a chip solder layer, an upper copper layer, a ceramic layer, a lower copper layer, a substrate solder layer and a substrate, the total order of the low-pass filter is 7. Figure 5 The total order is distributed according to the grouping results, and a low-pass filter model containing three parameters can be obtained. Its mathematical expression in the s domain is:

[0093]

[0094] Where f1, f2 and f3 are filter model parameters and satisfy f1 <f2<f3。

[0095] Figure 6 The figure is a schematic diagram of the simulation results of the heat flow characteristics of the power semiconductor device in a preferred embodiment of the present invention. When a 100W step loss is applied to the chip, the time domain step response mathematical expression of the output heat flow is:

[0096]

[0097] According to the mathematical expression, the output heat flow time domain simulation results of the finite element are fitted to obtain three parameters of the low-pass filter model: f1 is 0.2818 Hz, f2 is 16.5 Hz, and f3 is 109.4 Hz. It can be seen that the multi-order low-pass filter model provided by the above embodiment of the present invention can better restore the heat flow characteristics of the power semiconductor device.

[0098] In some embodiments of the present invention:

[0099] The amplitude-frequency characteristics of the low-pass filter should be as consistent as possible with the amplitude-frequency characteristics of the heat flow out of the power semiconductor device, and the characteristic frequency of the low-pass filter is 3. Specifically, the total order of the low-pass filter is consistent with the number of material layers inside the power semiconductor device.

[0100] The internal heat flow characteristics of power semiconductor devices can be obtained in the following ways: extract the time-domain output heat flow characteristics under simulation by setting a heat flow probe at the output position. Use the low-pass filter model to obtain the output heat flow expression, and use the output heat flow expression to approximate the time-domain output heat flow characteristics under simulation to obtain the low-pass filter model parameters.

[0101] The internal heat flow characteristics of power semiconductor devices can be obtained in the following ways: using a temperature sensor or a heat flow sensor, and measuring the time-domain output heat flow characteristics of the output position through the sensor. The output heat flow expression is obtained using the low-pass filter model, and the low-pass filter model parameters can be obtained by using the output heat flow expression to approximate the time-domain output heat flow characteristics under simulation. Furthermore, the output heat flow characteristics are measured using a temperature sensor, which can be estimated by dividing the time-domain temperature difference step response curve of the shell minus the heat sink by the thermal resistance of the shell minus the heat sink. The temperature measurement points of the shell and the heat sink should be directly below the power semiconductor device being measured, and the distance between the two measurement points should be as small as possible. The specific size is determined by the size of the device.

[0102] An embodiment of the present invention provides a device health status monitoring method based on the thermal flow characteristics of a power semiconductor device. The frequency domain modeling method of the thermal flow characteristics of a power semiconductor device in any of the above embodiments of the present invention is adopted. According to the frequency domain model of the thermal flow characteristics of the power semiconductor device, three characteristic frequencies f1, f2 and f3 are extracted and compared with the characteristic frequencies in a healthy state. When the frequency change rate of any one or more of the characteristic frequencies f1, f2 and f3 reaches a set threshold, it is judged that aging has occurred in a group of material layers corresponding to the characteristic frequencies, and the monitoring of the device health status is completed.

[0103] In some embodiments of the present invention:

[0104] The frequency domain model of the thermal flow characteristics of power semiconductor devices extracts three characteristic frequency parameters and compares them with the characteristic frequency parameters in a healthy state. When the parameter change rate reaches a certain level, it can be determined that the power semiconductor device has aged. Specifically, according to the grouping results, when any of the three characteristic frequencies changes, it can correspond to a corresponding group of material layers, and it can be determined that aging has occurred in this group of material layers. Optionally, the health status of the device can be determined by monitoring the model parameters of the low-pass filter offline or online.

[0105] Furthermore, before the aging problem occurs, appropriate control targets and control means can be selected to reduce device temperature fluctuations and control the speed of change of characteristic frequencies to delay the aging of power devices.

[0106] Furthermore, after the aging problem occurs, the aged components are promptly and accurately removed or shielded to ensure the safe operation of the entire system.

[0107] An embodiment of the present invention provides a terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it can be used to execute any one of the frequency domain modeling methods or device health status monitoring methods in the above-mentioned embodiments of the present invention.

[0108] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, it can be used to execute any one of the frequency domain modeling methods or device health status monitoring methods in the above embodiments of the present invention.

[0109] In the above two embodiments, optionally, the memory is used to store programs; the memory may include volatile memory (English: volatile memory), such as random access memory (English: random- access memory, abbreviated: RAM), such as static random access memory (English: static random-access memory, abbreviated: SRAM), double data rate synchronous dynamic random access memory (English: Double Data Rate Synchronous Dynamic RandomAccess Memory, abbreviated: DDR SDRAM), etc.; the memory may also include non-volatile memory (English: non-volatile memory), such as flash memory (English: flash memory). The memory is used to store computer programs (such as applications, functional modules, etc. that implement the above methods), computer instructions, etc., and the above computer programs, computer instructions, etc. can be partitioned and stored in one or more memories. And the above computer programs, computer instructions, data, etc. can be called by the processor.

[0110] The above-mentioned computer programs, computer instructions, etc. may be stored in one or more memories in partitions, and the above-mentioned computer programs, computer instructions, data, etc. may be called by a processor.

[0111] The processor is used to execute the computer program stored in the memory to implement the various steps in the method involved in the above embodiment. For details, please refer to the relevant description in the above method embodiment.

[0112] The processor and the memory may be independent structures or integrated structures. When the processor and the memory are independent structures, the memory and the processor may be coupled and connected via a bus.

[0113] The frequency domain modeling method, application, terminal and medium of the thermal flow characteristics of power semiconductor devices provided by the above embodiments of the present invention establish a multi-order low-pass filter model containing three characteristic frequencies based on the amplitude-frequency characteristics of the outflow heat flow of the power semiconductor device in the frequency domain, and use the low-pass filter model to construct a frequency domain model of the output heat flow of the power semiconductor device to achieve the simulation of the thermal flow characteristics of the power semiconductor device. The frequency domain modeling method, application, terminal and medium of the thermal flow characteristics of power semiconductor devices provided by the above embodiments of the present invention can accurately characterize the thermal flow characteristics of power semiconductor devices and improve the prediction accuracy of thermal characteristics under working conditions of power semiconductor devices.

[0114] Those skilled in the art know that, in addition to implementing the system and its various devices provided by the present invention in a purely computer-readable program code, the system and its various devices provided by the present invention can be made to implement the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices provided by the present invention can be considered as a hardware component, and the devices for implementing various functions included therein can also be considered as structures within the hardware component; the devices for implementing various functions can also be considered as both software modules for implementing the method and structures within the hardware component.

[0115] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A frequency domain modeling method for thermal flow characteristics of power semiconductor devices, characterized in that: Including: Based on the amplitude-frequency characteristics presented by the output heat flux of the power semiconductor device in the frequency domain, a multi-order low-pass filter model including 3 characteristic frequencies is established; where: The amplitude-frequency characteristics of the low-pass filter are consistent with the amplitude-frequency characteristics of the heat flow out of the device, and the characteristic frequency of the low-pass filter is 3; the total order of the low-pass filter is consistent with the number of internal material layers of the power semiconductor device; according to the bandwidth frequency of the amplitude-frequency gain of the heat flow between two adjacent layers of material inside the power semiconductor device, the multiple amplitude-frequency characteristics of the heat flow inside the power semiconductor device are divided into 3 groups, the order of the low-pass filter at each characteristic frequency is consistent with the number of amplitude-frequency characteristics of the internal heat flow of the power semiconductor device contained in each group, and the internal heat flow of the power semiconductor device contained in each group only uses 1 characteristic frequency, then the low-pass filter model G is constructed LPF (s) is: In the formula, s is the s-domain variable after Laplace transform, f1, f2, and f3 are the 3 characteristic frequencies of the low-pass filter, and satisfy f1 < f2 < f3; a, b, and c are the orders at each characteristic frequency of the low-pass filter; the 3 characteristic frequencies of the low-pass filter correspond to the amplitude-frequency characteristics of the output heat flux in the low-frequency band, medium-frequency band, and high-frequency band of the power semiconductor device from small to large; the order at each characteristic frequency of the low-pass filter is determined according to the grouping result of the amplitude-frequency characteristics of the internal heat flux of the power semiconductor device; Determine the 3 characteristic frequencies f1, f2, and f3 of the low-pass filter to complete the frequency-domain modeling of the heat flux characteristics of the power semiconductor device.

2. The frequency domain modeling method for thermal flow characteristics of a power semiconductor device according to claim 1, characterized in that: The power semiconductor device includes: silicon-based and non-silicon-based IGBTs, MOSFETs, transistors, thyristors, and diodes. The packaging forms of the power semiconductor device include: single-tube, welded, and press-fit structures. The heat sinks of the power semiconductor device include: air-cooled or water-cooled heat dissipation structures containing thermal grease and air-cooled or water-cooled heat dissipation structures in direct contact without thermal grease.

3. The frequency domain modeling method for thermal flow characteristics of power semiconductor devices according to claim 1, characterized in that: The construction method of the low-pass filter model includes: Using finite element simulation software, establish a geometric model of the power semiconductor device and perform mesh division, perform frequency-domain analysis and data processing on the temperature and heat flux signals in the geometric model to obtain a power semiconductor device model; Based on the power semiconductor model, extract the internal heat flux characteristics of the power semiconductor device, and use the frequency-domain simulation tool in the finite element simulation software to obtain the heat flux frequency-domain amplitude gain between adjacent material layers inside the power semiconductor device; Obtain the number of low-pass filter layers according to the number of material layers of the power semiconductor device, and then divide the multiple amplitude-frequency characteristics of the internal heat flux of the power semiconductor device into 3 groups according to the bandwidth frequency at which the amplitude-frequency gain of the heat flux between two adjacent layers of materials inside the power semiconductor device decays to -3 dB. The amplitude-frequency characteristics of each group are represented by a characteristic frequency f1, f2, and f3 respectively, that is, a multi-order low-pass filter model including 3 characteristic frequencies is obtained.

4. The frequency domain modeling method for thermal flow characteristics of a power semiconductor device according to claim 1, characterized in that: Among the orders at each characteristic frequency of the low-pass filter: a = 1, b = 3, c = 3.

5. The frequency domain modeling method for thermal flow characteristics of a power semiconductor device according to claim 1, characterized in that: The 3 characteristic frequencies f1, f2, and f3 of the low-pass filter are determined by any of the following methods: - Simulation-based method; - Experiment measurement-based method.

6. The frequency domain modeling method for thermal flow characteristics of a power semiconductor device according to claim 5, characterized in that: The simulation-based method includes: Extract the time-domain output heat flux characteristics under simulation through a heat flux probe set at the output position; According to the low-pass filter model G LPF (s) Obtain an output heat flow expression, use the output heat flow expression to approximate the time-domain output heat flow characteristics under simulation, and obtain the three characteristic frequencies f1, f2 and f3 of the low-pass filter.

7. The frequency domain modeling method for thermal flow characteristics of a power semiconductor device according to claim 5, characterized in that: The experiment measurement-based method includes: Measure the time-domain output heat flux characteristics at the output position under simulation using a temperature sensor or a heat flux sensor; According to the low-pass filter model G LPF (s) Obtain an output heat flow expression, use the output heat flow expression to approximate the time-domain output heat flow characteristics under simulation, and obtain the three characteristic frequencies f1, f2 and f3 of the low-pass filter.

8. The frequency domain modeling method for thermal flow characteristics of a power semiconductor device according to claim 1, characterized in that: The time-domain output heat flux characteristics of the output position under the simulation measured by the heat flux sensor are obtained by directly measuring the heat flux curve at the output position of the power semiconductor; the time-domain output heat flux characteristics of the output position under the simulation measured by the temperature sensor are estimated by placing temperature sensors on the shell surface and the heat sink surface directly below the output position of the power semiconductor, and then dividing the time-domain temperature difference step response curve of the shell minus the heat sink by the steady-state thermal resistance of the shell minus the heat sink.

9. The frequency domain modeling method for thermal flow characteristics of a power semiconductor device according to claim 6 or 7, characterized in that: The output heat flow expression is used to approximate the time domain output heat flow characteristics under simulation to obtain the three characteristic frequencies f1, f2 and f3 of the low-pass filter, including: According to the output heat flow expression, the function is approximated by using the curve fitting method to obtain the power semiconductor output heat flow P out The time domain step response fitting formula of (t) is: Where P in is the magnitude of the applied step loss, is the inverse Laplace transform, G LPF (s) is a low-pass filter model; According to the time domain step response fitting formula of the power semiconductor output heat flow, the three characteristic frequencies f1, f2 and f3 of the low-pass filter are extracted.

10. The frequency domain modeling method for thermal flow characteristics of a power semiconductor device according to claim 1, characterized in that: Also includes: The heat flow characteristics of the power semiconductor device are described by the characteristic frequencies f1, f2 and f3; wherein: The characteristic frequencies f1, f2 and f3 are combined with the lumped model to obtain transient characteristics of heat flow and temperature of the power semiconductor device, thereby achieving a description of the thermal characteristics of the power semiconductor device.

11. A device health status monitoring method based on thermal flow characteristics of power semiconductor devices, characterized in that: A frequency domain modeling method for the thermal flow characteristics of a power semiconductor device as described in any one of claims 1 to 10 is adopted. According to the frequency domain model of the thermal flow characteristics of the power semiconductor device, three characteristic frequencies f1, f2 and f3 are extracted and compared with the characteristic frequencies in a healthy state. When the frequency change rate of any one or more of the characteristic frequencies f1, f2 and f3 reaches a set threshold, it is judged that aging has occurred in a group of material layers corresponding to the characteristic frequencies, thereby completing the monitoring of the health status of the device.

12. A terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, it can be used to execute the method in any one of claims 1 to 10, or the method in claim 11.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, it can be used to execute the method described in any one of claims 1 to 10, or the method described in claim 11.

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