Fretting wear failure simulation method and system for spring type crimping IGBT (Insulated Gate Bipolar Translator) device

Abstract

The invention discloses a spring type crimping IGBT device fretting wear failure simulation method and system, and relates to the technical field of semiconductor devices.The spring type crimping IGBT device fretting wear failure simulation method comprises the steps that a spring type crimping IGBT finite element model and a multi-physics field coupling model are established based on COMSOL, and electric field, thermal field and mechanical field boundary conditions are set; calculating the wear depth of the contact surface according to an Archard model, and circularly updating the relative roughness and the relative surface slope parameter of the contact surface based on the fretting wear power; and monitoring junction temperature, saturation voltage drop of a collector and an emitter and thermal resistance in real time, and judging fretting wear failure of the spring type crimping IGBT device based on failure conditions. According to the method, through multi-physics field finite element modeling and fretting wear loss calculation, contact surface relative roughness and relative surface slope changes caused by fretting wear are simulated, then electrical and thermal performance parameter change trends of a device are analyzed, and deviation caused by single physics field analysis is avoided; by setting failure conditions, the fretting wear failure of the device can be automatically judged in the analogue simulation process.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and specifically to a simulation method and system for fretting wear failure of a spring-type press-fit IGBT device. Background Art

[0002] With the rapid development of flexible DC transmission (VSC-HVDC) technology, the performance requirements for power devices are getting higher and higher. Press-pack insulated gate bipolar transistor (Press-pack IGBT) modules have gradually become the preferred devices in high-voltage and high-current DC transmission systems due to their advantages such as high reliability, high power density, and fail-safe short-circuit mode. Among them, the spring-type press-fit IGBT module has greater advantages and application potential in the assembly of multiple sub-modules and higher current rating scenarios due to its pressure balance and assembly flexibility.

[0003] However, during the long-term operation of spring-type press-fit IGBT devices, fretting wear failure has become one of their typical failure modes. Fretting wear refers to the friction and wear phenomenon that occurs between the contact interface materials under small relative movements. At present, the research on fretting wear failure mainly focuses on experimental tests and simple simulation analyses, lacking an in-depth understanding of the multi-physical field coupling effect inside the device and the fretting wear mechanism. First, most of the existing methods only consider the influence of a single physical field and ignore the interaction between multi-physical fields, resulting in a large deviation between the simulation results and the actual situation; second, the existing methods do not have an in-depth understanding of the fretting wear mechanism, usually only considering the calculation of the wear amount, while ignoring the change in the surface topography of the contact surface during the wear process and its influence on the device performance parameters. Summary of the Invention

[0004] In view of the above problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is that the existing simulation methods for fretting wear failure of spring-type press-fit IGBT devices lack multi-physical field coupling analysis and an in-depth understanding of the fretting wear mechanism.

[0006] To solve the above technical problem, the present invention provides the following technical solution: A simulation method for fretting wear failure of a spring-type press-fit IGBT device, including establishing a finite element model and a multi-physical field coupling model of the spring-type press-fit IGBT based on COMSOL software, and setting the boundary conditions of the electric field, thermal field, and mechanical field; calculating the wear depth of the contact surface according to the Archard model, and updating the relative roughness and relative surface slope parameters of the contact surface based on the fretting wear power cycle; real-time monitoring of the junction temperature, collector-emitter saturation voltage drop, and thermal resistance, and judging the fretting wear failure of the spring-type press-fit IGBT device based on the failure conditions.

[0007] As a preferred solution of the method for simulating fretting wear failure of a spring-type press-fit IGBT device according to the present invention, the finite element model of the spring-type press-fit IGBT includes an emitter copper layer, a spring structure, a copper pillar, an emitter aluminum layer, an emitter molybdenum layer, a gate, an IGBT chip, and a collector molybdenum layer; the multi-physics field coupling model includes thermal field-mechanical field coupling, electric field-thermal field coupling, and mechanical field-electric field coupling; the thermal field-mechanical field coupling includes, the thermal field-mechanical field coupling taking into account thermal deformation and contact thermal resistance, calculating the thermal deformation amount of the spring-type press-fit IGBT, expressed as:

[0008] ε=α·(TT ref )

[0009] Where ε represents the deformation, α represents the thermal expansion coefficient, T represents the real-time temperature, and T ref represents the initial reference temperature; the contact thermal resistance of the spring-type press-fit IGBT finite element model is calculated as:

[0010]

[0011] Among them, R th-thermal represents the contact thermal resistance, A represents the contact area, k con represents thermal conductivity, m represents the relative surface slope between contact surfaces, σ represents the relative roughness of the contact surface, P represents the contact pressure, H c Represents the microhardness value of the material with low microhardness; the electric field-thermal field coupling includes, the electric field-thermal field coupling takes into account Joule heat and heat conduction, then the Joule heat of the electric field-thermal field coupling is expressed as:

[0012] Q j =J·E

[0013] Where J represents the current density vector, E represents the electric field vector, and the heat conduction of the electric field-thermal field coupling is expressed as:

[0014]

[0015] Where ρ represents density, C p represents specific heat capacity, κ(T) represents thermal conductivity, Q j represents Joule heat, ΔT represents temperature gradient; the mechanical field-electric field coupling includes, the mechanical field-electric field coupling considers the influence of pressure on the contact resistance of the spring-type press-fit IGBT device, and the calculation formula of pressure on the contact resistance of the spring-type press-fit IGBT device is expressed as:

[0016]

[0017] where σ1 and σ2 represent the resistivity of the contact material.

[0018] As a preferred embodiment of the simulation method for fretting wear failure of the spring - type press - fit IGBT device according to the present invention, the setting of the boundary conditions of the electric field, thermal field, and mechanical field includes applying pressure and conduction current on the collector side, fixing and grounding the emitter side, and setting the water - cooling heat dissipation coefficient, ambient temperature, power cycle period, and duty ratio; the spring - type press - fit IGBT chip adopts refined mesh division, the spring structure adopts coarsened mesh division, and the conventional mesh division built in COMSOL is selected for each layer of material in the spring - type press - fit IGBT device.

[0019] As a preferred embodiment of the simulation method for fretting wear failure of the spring - type press - fit IGBT device according to the present invention, the calculation of the wear depth of the contact surface includes dividing the contact surface into a copper layer - emitter aluminum layer, emitter aluminum - emitter molybdenum layer, emitter molybdenum layer - chip emitter side, and chip collector side - collector molybdenum layer, and calculating the wear amount per single cycle, which is expressed as:

[0020]

[0021] where Δl w represents the wear amount within a cycle period Δt, P represents the contact pressure, H c is the micro - hardness value of the material with a smaller micro - hardness between the contact surfaces, v s represents the relative sliding speed between the contact materials, and ρ k represents the probability of wear occurring between the contact surfaces.

[0022] The probability ρ of wear occurring between the contact surfaces k is from 1×10 -4 to 4×10 -4 , and in the embodiments of the present application, ρ k takes the value of 4×10 -4 .

[0023] Through the accumulation formula, the wear depth of the material after the Nth power cycle is calculated, which is expressed as:

[0024] l N =l N-1 +Δl w

[0025] where l N represents the total wear depth, and l N-1 represents the wear depth of the material after the (N - 1)th cycle.

[0026] As a preferred embodiment of the method for simulating the fretting wear failure of a spring - pressed IGBT device according to the present invention, wherein: the step of updating the relative surface roughness and relative surface slope parameters of the contact surface based on fretting wear power cycling includes that during the fretting wear process of the contact surface, if the material with a lower micro - hardness shows wear loss, then after the Nth cycle, the relative surface roughness of the contact surface inside the spring - pressed IGBT device is expressed as:

[0027]

[0028] wherein, σ r_N represents the relative surface roughness of the contact surface inside the spring - pressed IGBT device after the Nth cycle, σ h_i represents the initial surface roughness of the material with a higher micro - hardness between the contact surfaces of the spring - pressed IGBT device, and σ s_i represents the initial surface roughness of the material with a lower micro - hardness between the contact surfaces of the spring - pressed IGBT device; converting the surface slope and surface roughness of the material, after the Nth cycle, the relative surface slope between the contact surfaces inside the spring - pressed IGBT device is expressed as:

[0029]

[0030] wherein, m h_i represents the initial surface slope of the material with a higher micro - hardness between the contact surfaces of the spring - pressed IGBT device, and m s_N represents the value of the surface slope of the material with a lower micro - hardness between the contact surfaces of the spring - pressed IGBT device after the Nth cycle.

[0031] As a preferred embodiment of the method for simulating the fretting wear failure of a spring - pressed IGBT device according to the present invention, wherein: the step of real - time monitoring the junction temperature, collector - emitter saturation voltage drop, and thermal resistance includes that in the COMSOL software, every time a power cycle of the simulation of the fretting wear failure of the spring - pressed IGBT device is completed, the simulation parameters are extracted in real - time; the simulation parameters include the junction temperature, collector - emitter saturation voltage drop, and thermal resistance parameters.

[0032] As a preferred solution of the simulation method for fretting wear failure of a spring - type press - fit IGBT device according to the present invention, the fretting wear failure judgment of the spring - type press - fit IGBT device based on failure conditions includes: based on the junction temperature, collector - emitter saturation voltage drop, and thermal resistance parameters monitored in real - time, when any simulation parameter reaches the failure condition, the solver is interrupted and the current number of cycles and the parameter change trend are output; and an analysis report is generated according to the junction temperature, collector - emitter saturation voltage drop, and thermal resistance value of the last effective cycle to clarify the main factors of failure; the failure conditions include that the junction temperature rises by more than 20%, the collector - emitter saturation voltage drop rises by more than 5%, and the thermal resistance rises by more than 20%.

[0033] Another object of the present invention is to provide a simulation system for fretting wear failure of a spring - type press - fit IGBT device, which can solve the problem that the existing technology ignores the interaction between multiple physical fields, resulting in a large deviation between the simulation results and the actual situation by constructing a multi - physical - field coupling model.

[0034] As a preferred solution of the simulation system for fretting wear failure of a spring - type press - fit IGBT device according to the present invention, it includes a model construction module, a power cycle module, and a failure judgment module; the model construction module is used to establish a finite - element model and a multi - physical - field coupling model of the spring - type press - fit IGBT based on COMSOL software and set the boundary conditions of the electric field, thermal field, and mechanical field; the power cycle module is used to calculate the wear depth of the contact surface according to the Archard model and update the relative roughness and relative surface slope parameters of the contact surface based on the fretting wear power cycle; the failure judgment module is used to monitor the junction temperature, collector - emitter saturation voltage drop, and thermal resistance in real - time and judge the fretting wear failure of the spring - type press - fit IGBT device based on the failure conditions.

[0035] A computer device includes a memory and a processor, the memory stores a computer program, and the processor executes the computer program to implement the steps of the simulation method for fretting wear failure of a spring - type press - fit IGBT device.

[0036] A computer - readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the simulation method for fretting wear failure of a spring - type press - fit IGBT device are implemented.

[0037] Advantages of the present invention: The method for simulating the fretting wear failure of a spring - pressed IGBT device provided by the present invention can, through multi - physical - field finite - element modeling and fretting wear loss calculation, simulate the changes in the relative roughness and relative surface slope of the contact surface caused by fretting wear during the long - term fretting wear power cycle of the spring - pressed IGBT device, and further analyze the changing trends of the electrical and thermal performance parameters of the device, avoiding the deviation caused by single - physical - field analysis; by setting failure conditions, it can automatically determine the occurrence of fretting wear failure of the device during the simulation process and analyze the failure reasons; by simulating the failure time and service life of the device, unnecessary device replacement and maintenance can be avoided, thereby reducing the use cost of the device; by considering the changes in the surface topography of the contact surface during the wear process, such as the increase in surface roughness and its impact on thermal resistance, the failure risk of the device can be more comprehensively evaluated. Brief Description of the Drawings

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for description in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0039] Figure 1 It is the overall flowchart of a method for simulating the fretting wear failure of a spring - pressed IGBT device provided by the first embodiment of the present invention.

[0040] Figure 2 It is the finite - element model diagram of a spring - pressed IGBT for a method for simulating the fretting wear failure of a spring - pressed IGBT device provided by the first embodiment of the present invention.

[0041] Figure 3 It is the boundary - condition setting diagram of the finite - element model of a spring - pressed IGBT for a method for simulating the fretting wear failure of a spring - pressed IGBT device provided by the first embodiment of the present invention.

[0042] Figure 4 It is the contact - surface division diagram of a spring - pressed IGBT device for a method for simulating the fretting wear failure of a spring - pressed IGBT device provided by the second embodiment of the present invention.

[0043] In the figure, contact surface 1 is between the copper layer and the emitter aluminum layer, contact surface 2 is between the emitter aluminum layer and the emitter molybdenum layer, contact surface 3 is between the emitter molybdenum layer and the emitter side of the IGBT chip, and contact surface 4 is between the collector side of the IGBT chip and the collector molybdenum layer.

[0044] Figure 5The graph showing the changing trend of the simulated junction temperature during power cycling of the spring-type press-fit IGBT device for the micro-motion wear failure simulation method provided in the second embodiment of the present invention.

[0045] Figure 6 The graph showing the changing trends of the micro-motion wear failure junction temperature and the saturation voltage drop between the collector and the emitter for the micro-motion wear failure simulation method of the spring-type press-fit IGBT device provided in the second embodiment of the present invention.

[0046] Figure 7 The graph showing the changing trend of the relative roughness of each contact surface for the micro-motion wear failure simulation method of the spring-type press-fit IGBT device provided in the second embodiment of the present invention.

[0047] Figure 8 The overall flowchart of the micro-motion wear failure simulation system of the spring-type press-fit IGBT device provided in the third embodiment of the present invention. Detailed implementation manners

[0048] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the drawings in the specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0049] Embodiment 1, referring to Figures 1 - 3 , which is an embodiment of the present invention, provides a micro-motion wear failure simulation method for a spring-type press-fit IGBT device, including:

[0050] S1: Establish a finite element model and a multi-physics field coupling model of the spring-type press-fit IGBT based on COMSOL software, and set the boundary conditions of the electric field, thermal field, and mechanical field.

[0051] Furthermore, referring to Figure 2 , the finite element model of the spring-type press-fit IGBT includes an emitter copper layer, a spring structure, a copper column, an emitter aluminum layer, an emitter molybdenum layer, a gate, an IGBT chip, and a collector molybdenum layer.

[0052] The multi-physics field coupling model includes thermal field-mechanical field coupling, electric field-thermal field coupling, and mechanical field-electric field coupling; the thermal field-mechanical field coupling includes considering thermal deformation and contact thermal resistance in the thermal field-mechanical field coupling, and calculating the thermal deformation amount of the spring-type press-fit IGBT, expressed as:

[0053] ε = α·(T - T ref )

[0054] Among them, ε represents the deformation amount, α represents the coefficient of thermal expansion, T represents the real-time temperature, and T ref represents the initial reference temperature; calculating the contact thermal resistance of the spring-type press-fit IGBT finite element model, which is expressed as:

[0055]

[0056] Among them, R th-thermal represents the contact thermal resistance, A represents the contact area, k con represents the thermal conductivity, m represents the relative surface slope of the contact, σ represents the relative roughness of the contact surface, P represents the contact pressure, and H c represents the microhardness value of the material with smaller microhardness; the electric field-thermal field coupling includes that the electric field-thermal field coupling considers Joule heat and heat conduction, then the Joule heat of the electric field-thermal field coupling is expressed as:

[0057] Q j = J·E

[0058] Among them, J represents the current density vector, and E represents the electric field vector; the heat conduction of the electric field-thermal field coupling is expressed as:

[0059]

[0060] Among them, ρ represents the density, C p represents the specific heat capacity, κ(T) represents the thermal conductivity, Q j represents the Joule heat, and ΔT represents the temperature gradient; the mechanical field-electric field coupling includes that the mechanical field-electric field coupling considers the influence of pressure on the contact resistance of the spring-type press-fit IGBT device, then the calculation formula for the influence of pressure on the contact resistance of the spring-type press-fit IGBT device is expressed as:

[0061]

[0062] Among them, σ1 and σ2 represent the resistivity of the contact materials.

[0063] It should be noted that referring to Figure 3 , setting the electric field, thermal field and mechanical field boundary conditions includes applying pressure and conducting current on the collector side, fixing and grounding the emitter side, and setting the water-cooling heat dissipation coefficient, ambient temperature, power cycle period and duty ratio; the spring-type press-fit IGBT chip adopts refined mesh division, the spring structure adopts coarsened mesh division, and each layer of material in the spring-type press-fit IGBT device selects the built-in conventional mesh division of COMSOL.

[0064] It should also be noted that the number of mesh division units of the spring-type press-fit IGBT device is 53605.

[0065] S2: Calculate the wear depth of the contact surface according to the Archard model, and update the relative roughness and relative surface slope parameters of the contact surface based on the fretting wear power cycle.

[0066] Furthermore, calculating the wear depth of the contact surface includes dividing the contact surface into copper layer-emitter aluminum layer, emitter aluminum-emitter molybdenum layer, emitter molybdenum layer-chip emitter side, and chip collector side-collector molybdenum layer, and calculating the wear amount per cycle, expressed as:

[0067]

[0068] where, Δl w represents the wear amount within a cycle period Δt, P represents the contact pressure, H c is the microhardness value of the material with a smaller microhardness between the contact surfaces, v s represents the relative sliding speed between the contact materials, ρ k represents the probability of wear occurring between the contact surfaces; through the accumulation formula, calculate the wear depth of the material after the Nth power cycle, expressed as:

[0069] l N = l N-1 +Δl w

[0070] where, l N represents the total wear depth, l N-1 represents the wear depth of the material after the (N - 1)th cycle.

[0071] It should also be noted that updating the relative roughness and relative surface slope parameters of the contact surface based on the fretting wear power cycle includes, during the fretting wear process of the contact surface, if the material with a smaller microhardness shows wear loss, then after the Nth cycle, the relative roughness of the contact surface within the spring-type press-fit IGBT device is expressed as:

[0072]

[0073] where, σ r_N represents the relative roughness of the contact surface within the spring-type press-fit IGBT device after the Nth cycle, σ h_i represents the initial surface roughness of the material with a larger microhardness between the contact surfaces within the spring-type press-fit IGBT device, σ s_i represents the initial surface roughness of the material with a smaller microhardness between the contact surfaces within the spring-type press-fit IGBT device.

[0074] The conversion formula in the conversion between the material surface slope and the surface roughness is expressed as:

[0075] m = 0.152·σ 0.4

[0076] Perform conversion using Tanner's formula.

[0077] Convert the surface slope of the material and the surface roughness. After the Nth cycle, the relative surface slope between the inner contact surfaces of the spring-type press-fit IGBT device is expressed as:

[0078]

[0079] Where m h_i represents the initial value of the surface slope of the material with a greater microhardness between the inner contact surfaces of the spring-type press-fit IGBT device, and m s_N represents the value of the surface slope of the material with a smaller microhardness between the inner contact surfaces of the spring-type press-fit IGBT device after the Nth cycle.

[0080] S3: Monitor the junction temperature, collector-emitter saturation voltage drop, and thermal resistance in real time, and perform failure judgment on the fretting wear failure of the spring-type press-fit IGBT device based on the failure conditions.

[0081] Furthermore, the real-time monitoring of the junction temperature, collector-emitter saturation voltage drop, and thermal resistance includes, in the COMSOL software, extracting the simulation parameters in real time every time the fretting wear failure simulation of the spring-type press-fit IGBT device completes a power cycle; the simulation parameters include the junction temperature, collector-emitter saturation voltage drop, and thermal resistance parameters.

[0082] It should be noted that the failure judgment on the fretting wear failure of the spring-type press-fit IGBT device based on the failure conditions includes, based on the real-time monitored junction temperature, collector-emitter saturation voltage drop, and thermal resistance parameters, when any one of the simulation parameters reaches the failure condition, interrupt the solver and output the current number of cycles and the parameter change trend; and generate an analysis report based on the junction temperature, collector-emitter saturation voltage drop, and thermal resistance values of the last valid cycle to clarify the main factors of failure; the failure conditions include the junction temperature rising by more than 20%, the collector-emitter saturation voltage drop rising by more than 5%, and the thermal resistance rising by more than 20%.

[0083] Example 2, referring to Figures 4 - 7 , which is an embodiment of the present invention, provides a method for simulating the fretting wear failure of a spring-type press-fit IGBT device. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0084] First, establish a finite element model of the spring-type press-fit IGBT device through the COMSOL software, construct a multi-physics field coupling model, and refer to Figure 4Divide the contact surface of the spring - type press - fit IGBT device, and divide the contact surface into Contact Surface 1, Contact Surface 2, Contact Surface 3, and Contact Surface 4. Consider the interaction of the electric field, temperature field, and mechanical field in the model, and set the boundary conditions of the electric field, thermal field, and mechanical field in Table 1.

[0085] Table 1 Boundary Conditions of Electric Field, Thermal Field, and Mechanical Field for Power Cycling of Spring - type Press - fit IGBT Device

[0086] Parameter Value Parameter Value Cycle period (s) 140 Conduction current (A) 50 Duty cycle (1) 0.5 Applied pressure (N) 1200 Ambient temperature (°C) 25 <![CDATA[Water cooling heat dissipation coefficient W / (m 2 ·K)]]> 6000

[0087] Subsequently, calculate the wear depth of the IGBT device contact surface according to the Archard model, and update the relative roughness and relative surface slope parameters of the contact surface based on fretting wear power cycling. During the simulation process, monitor the parameter changes of the junction temperature, collector - emitter saturation voltage drop, and thermal resistance in real - time at the end of each power cycle, and judge whether it fails based on the failure conditions. When it is judged that the IGBT device fails, the simulation ends and the simulation results are obtained.

[0088] Figure 5 For the change trend of the junction temperature of the spring - type press - fit IGBT device with the increase in the number of power cycles during fretting wear, during the fretting wear failure process of the spring - type press - fit IGBT device, the peak value of the device's junction temperature fluctuation increases with the increase in the number of cycles. The maximum increase in the device's highest junction temperature is the largest from the 1st cycle to the 10000th cycle, rising by about 1.85 °C. When the cycle reaches 20000 times, the highest junction temperature of the spring - type press - fit IGBT device rises to 117.54 °C. When the cycle reaches 30000 times, the highest junction temperature of the spring - type press - fit IGBT device rises to 119.01 °C. Finally, the power - cycle junction temperature fluctuation range of the spring - type press - fit IGBT device rises from about 89.05 °C to about 95.65 °C.

[0089] Figure 6 For the change trends of the junction temperature and collector - emitter saturation voltage drop of the spring - type press - fit IGBT device, according to Figure 6 (a), during the fretting wear failure simulation of the spring - type press - fit IGBT device, the maximum junction temperature of the device is positively correlated with the number of cycles. As the number of cycles increases continuously, it finally rises from 114.05 °C to 120.65 °C. According to Figure 6 (b), during the fretting wear failure simulation of the spring - type press - fit IGBT device, the collector - emitter saturation voltage drop of the device is also positively correlated with the number of cycles, but the change is relatively small compared to the junction temperature change. From the first power cycle to before the device undergoes fretting wear failure, the collector - emitter saturation voltage drop only increases by 0.15 V.

[0090] Figure 7To study the change trend of the relative roughness of each contact surface in the spring-type press-fit IGBT device during the fretting wear failure simulation, the roughness of contact surface 2, i.e., the emitter aluminum layer and the emitter molybdenum layer, increased the most. During the fretting wear failure simulation, the relative roughness of contact surface 2 increased by approximately 0.72 μm. Followed by contact surface 1, during the fretting wear failure simulation, the relative roughness of contact surface 1 increased by approximately 0.48 μm. The relative roughness of contact surface 3 increased by 0.09 μm during the fretting wear failure simulation, and contact surface 4 increased the least, with its relative roughness increasing by only approximately 0.06 μm.

[0091] According to the failure conditions to judge the simulation results, during the power cycle process before the spring-type press-fit IGBT device undergoes fretting wear failure, the junction temperature increased by a total of 6.60 °C, an increase of 5.8%; the thermal resistance increased by a total of 0.0081 K / W, an increase of 5.4%, while the collector-emitter saturation voltage increased by a total of 0.15 V, exceeding 5% of the collector-emitter saturation voltage. Therefore, the fretting wear failure of the spring-type press-fit IGBT device is caused by the excessive collector-emitter saturation voltage.

[0092] In summary, the method of the present invention can obtain the change trend of each performance parameter during the simulation of the fretting wear failure of the spring-type press-fit IGBT device, laying a foundation for establishing the fretting wear failure life model of the spring-type press-fit IGBT device.

[0093] Example 3, referring to Figure 8 , which is an embodiment of the present invention, provides a fretting wear failure simulation system for a spring-type press-fit IGBT device, including a model construction module, a power cycle module, and a failure judgment module.

[0094] Among them, the model construction module is used to establish a finite element model and a multi-physical field coupling model of the spring-type press-fit IGBT based on COMSOL software, and set the boundary conditions of the electric field, thermal field, and mechanical field; the power cycle module is used to calculate the wear depth of the contact surface according to the Archard model, and update the relative roughness and relative surface slope parameters of the contact surface based on the fretting wear power cycle; the failure judgment module is used to monitor the junction temperature, collector-emitter saturation voltage, and thermal resistance in real time, and judge the fretting wear failure of the spring-type press-fit IGBT device based on the failure conditions.

[0095] If a function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods of various embodiments of the present invention. The aforementioned storage medium includes: USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs, etc., which are various media that can store program codes.

[0096] The logic and / or steps represented in the flowchart or described in other ways herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch instructions from the instruction execution system, apparatus, or device and execute the instructions), or in combination with these instruction execution systems, apparatuses, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device.

[0097] More specific examples (nonexhaustive list) of computer-readable media include the following: electrical connection parts with one or more wirings (electronic devices), portable computer disk cartridges (magnetic devices), random access memories (RAMs), read-only memories (ROMs), erasable programmable read-only memories (EPROMs or flash memories), optical fiber devices, and portable compact disc read-only memories (CDROMs). Additionally, a computer-readable medium can even be paper or other suitable media on which a program can be printed, because, for example, the program can be obtained electronically by optically scanning the paper or other media, followed by editing, interpretation, or, if necessary, other appropriate processing, and then stored in a computer memory.

[0098] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logic functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc. It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

[0099] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A simulation method for the fretting wear failure of a spring-type press-fit IGBT device, characterized in that, Including: Based on COMSOL software, a finite element model and a multi-physics coupling model of a spring-type press-fit IGBT are established, and the boundary conditions of the electric field, thermal field and mechanical field are set; According to the Archard model, the wear depth of the contact surface is calculated, and the relative roughness and relative surface slope parameters of the contact surface are updated based on the fretting wear power cycle; The junction temperature, collector-emitter saturation voltage drop and thermal resistance are monitored in real time, and the fretting wear failure of the spring-type press-fit IGBT device is judged based on the failure conditions.

2. The spring-type press-fit IGBT device fretting wear failure simulation method according to claim 1, characterized in that: The spring-type press-fit IGBT finite element model includes an emitter copper layer, a spring structure, a copper column, an emitter aluminum layer, an emitter molybdenum layer, a gate, an IGBT chip and a collector molybdenum layer; The multi-physics coupling model includes thermal field-mechanical field coupling, electric field-thermal field coupling and mechanical field-electric field coupling; The thermal field-mechanical field coupling includes that the thermal field-mechanical field coupling considers thermal deformation and contact thermal resistance, and calculates the thermal deformation amount of the spring-type press-fit IGBT, expressed as: ε = α·(T - T ref ) Among them, ε represents the deformation amount, α represents the coefficient of thermal expansion, T represents the real-time temperature, and T ref represents the initial reference temperature; Calculate the contact thermal resistance of the spring-type press-fit IGBT finite element model, expressed as: Among them, R th-thermal represents the contact thermal resistance, A represents the contact area, and k con represents the thermal conductivity, m represents the relative surface slope between the contact surfaces, σ represents the relative roughness of the contact surfaces, P represents the contact pressure, and H c represents the microhardness value of the material with a smaller microhardness; The electric field-thermal field coupling includes that the electric field-thermal field coupling considers Joule heat and heat conduction, then the Joule heat of the electric field-thermal field coupling, expressed as: Q j = J·E Where, J represents the current density vector and E represents the electric field vector; The heat conduction of the electric field-thermal field coupling, expressed as: where ρ represents density, C p represents specific heat capacity, κ(T) represents thermal conductivity, Q j represents Joule heat, and ΔT represents temperature gradient; The mechanical field-electric field coupling includes that the mechanical field-electric field coupling considers the influence of pressure on the contact resistance of the spring-type press-fit IGBT device, then the calculation formula of the pressure on the contact resistance of the spring-type press-fit IGBT device, expressed as: Where, σ1 and σ2 represent the resistivity of the contact materials.

3. The spring-type crimping IGBT device fretting wear failure simulation method according to claim 2, characterized in that: The setting of the boundary conditions of the electric field, thermal field and mechanical field includes applying pressure and conduction current on the collector side, fixing and grounding the emitter side, and setting the water-cooling heat dissipation coefficient, ambient temperature, power cycle period and duty ratio; The spring-type press-fit IGBT chip uses refined mesh division, the spring structure uses coarsened mesh division, and the conventional mesh division built in COMSOL is selected for each layer of material in the spring-type press-fit IGBT device.

4. The spring-type press-fit IGBT device fretting wear failure simulation method according to claim 3, characterized in that: The calculation of the wear depth of the contact surface includes dividing the contact surface into copper layer-emitter aluminum layer, emitter aluminum layer-emitter molybdenum layer, emitter molybdenum layer-chip emitter side and chip collector side-collector molybdenum layer, and calculating the single-cycle wear amount, expressed as: where, Δl w represents the wear amount within a cycle period Δt, P represents the contact pressure, H c is the microhardness value of the material with a smaller microhardness between the contact surfaces, v s represents the relative sliding speed between the contacting materials, ρ k represents the probability of wear occurring between the contact surfaces; Through the accumulation formula, calculate the wear depth of the material after the Nth power cycle, expressed as: l N = l N-1 + Δl w Among them, l N represents the total wear depth, and l N-1 represents the wear depth of the material after the (N - 1)-th cycle.

5. The spring-type press-fit IGBT device fretting wear failure simulation method according to claim 4, wherein: The update of the relative roughness and relative surface slope parameters of the contact surface based on the fretting wear power cycle includes that during the fretting wear process of the contact surface, the material with a smaller microhardness shows wear loss, then after the Nth cycle period, the relative roughness of the contact surface in the spring-type press-fit IGBT device, expressed as: Among them, σ r_N represents the relative roughness of the inner contact surface in the spring-type press-fit IGBT device after the Nth cycle period, and σ h_i represents the initial surface roughness of the material with a relatively large microhardness between the inner contact surfaces of the spring-type press-fit IGBT device, and σ s_i represents the initial surface roughness of the material with a relatively small microhardness between the inner contact surfaces of the spring-type press-fit IGBT device; Convert the surface slope and surface roughness of the material, and after the Nth cycle period, the relative surface slope between the contact surfaces in the spring-type press-fit IGBT device, expressed as: Among them, m h_i represents the initial value of the surface slope of the material with a relatively large microhardness between the inner contact surfaces of the spring-type press-fit IGBT device, and m s_N represents the value of the surface slope of the material with a relatively small microhardness between the inner contact surfaces of the spring-type press-fit IGBT device after the Nth cycle.

6. The spring-type press-fit IGBT device fretting wear failure simulation method according to claim 5, characterized in that: The real-time monitoring of the junction temperature, collector-emitter saturation voltage drop and thermal resistance includes that in the COMSOL software, every time a power cycle of the fretting wear failure simulation of the spring-type press-fit IGBT device is completed, the simulation parameters are extracted in real time; The simulation parameters include junction temperature, collector-emitter saturation voltage drop, and thermal resistance parameters.

7. The spring-type press-fit IGBT device fretting wear failure simulation method according to claim 6, characterized in that: The determination of fretting wear failure of the spring-type press-fit IGBT device based on failure conditions includes, based on the junction temperature, collector-emitter saturation voltage drop, and thermal resistance parameters monitored in real time. When any simulation parameter reaches the failure condition, the solver is interrupted and the current cycle number and the parameter change trend are output. And an analysis report is generated based on the junction temperature, collector-emitter saturation voltage drop, and thermal resistance value of the last effective cycle to clarify the main factors of failure. The failure conditions include a junction temperature rise exceeding 20%, a collector-emitter saturation voltage drop rise exceeding 5%, and a thermal resistance rise exceeding 20%.

8. A system adopting the spring-type press-fit IGBT device fretting wear failure simulation method as described in any one of claims 1 to 7, characterized in that: It includes a model construction module, a power cycle module, and a failure determination module. The model construction module is used to establish a finite element model and a multi-physical field coupling model of the spring-type press-fit IGBT based on COMSOL software, and set the boundary conditions of the electric field, thermal field, and mechanical field. The power cycle module is used to calculate the wear depth of the contact surface according to the Archard model, and update the relative roughness and relative surface slope parameters of the contact surface based on the fretting wear power cycle. The failure determination module is used to monitor the junction temperature, collector-emitter saturation voltage drop, and thermal resistance in real time, and determine the fretting wear failure of the spring-type press-fit IGBT device based on the failure conditions.

9. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, the steps of the fretting wear failure simulation method of the spring-type press-fit IGBT device described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the steps of the fretting wear failure simulation method of the spring-type press-fit IGBT device described in any one of claims 1 to 7 are implemented.

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