Multi-physical domain controller limiting temperature estimation method based on parameter transfer
By using a cross-physical domain parameter transfer method, the problem of inconsistent time scales in multi-physical domain coupled analysis is solved, enabling accurate prediction of the extreme temperature of controller components and improving the simulation accuracy and reliability of thermal safety design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-19
- Publication Date
- 2026-03-13
AI Technical Summary
Existing technologies struggle to achieve efficient and accurate coupled analysis when time scales differ across multiple physical domains, such as electromagnetic, thermal, and fluid domains. This results in inaccurate calculations of the extreme temperatures of internal components of the controller, impacting the system's safety margin and reliability.
By transferring key parameters across physical domains, parasitic parameters, electrical characteristics, and losses related to temperature and frequency are separated and iteratively updated according to time scales, enabling rapid convergence of the temperature field across multiple physical domains and accurate estimation of the limit temperatures of each component of the controller.
It enables accurate prediction of the extreme temperatures of each component of the controller, improves the reliability of system design and thermal management, solves the problems of large simulation volume and low accuracy in traditional methods, and significantly improves the simulation accuracy and calculation reliability of thermal safety design.
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Figure CN121655729A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of motor and controller technology, and particularly relates to a method for estimating the extreme temperature of a multi-physics domain controller based on parameter transfer. Background Technology
[0002] Power devices made from third-generation semiconductor material SiC (Silicon Carbide) offer advantages such as high temperature resistance, higher efficiency, and higher frequency operation, and are increasingly being used in traction systems for electric vehicles, rail vehicles, and public transportation vehicles. With the continuous increase in controller power density, the temperature rise of the controller poses a challenge to its reliable operation, requiring accurate measurement of the temperature of the power devices within the controller. SiC power devices, with their higher switching speed, are more susceptible to the influence of parasitic parameters in the controller, including the equivalent series inductance of capacitors and stray inductance of the busbar. These parasitic parameters are affected by electromagnetic resonance. The losses of capacitors, busbars, and power devices are influenced by the combined effects of control circuit current, frequency, and temperature. Current research has conducted electromagnetic-thermal coupling analysis of busbar stray inductance, resistance, and temperature. However, the thermal analysis only considers busbar heating and does not take into account the heat dissipation devices of power devices, capacitors, and controllers. Therefore, the calculated busbar temperature coupling differs significantly from reality. Furthermore, research on the temperature rise of power devices does not comprehensively consider the electromagnetic influence of the equivalent series inductance of capacitors in the controller system, the stray inductance of the busbar, and the impact of stray parameters on power device losses. Therefore, if it is necessary to accurately measure the power devices and internal temperature of the controller, a comprehensive coupled analysis of the controller in the electromagnetic and thermophysical domain is required.
[0003] Meanwhile, as controller power density continues to increase, the extreme temperatures of key components such as power devices, capacitors, and busbars are gradually becoming the main bottlenecks limiting the reliable operation of controllers. Extreme temperatures not only determine whether devices can operate safely, but also directly affect their aging rate, probability of thermal failure, and overall controller lifespan. When the instantaneous temperature of a local area of the controller exceeds the extreme temperature under high frequency, high current, or high magnetic flux density conditions, it may trigger abrupt changes in parasitic parameters, a sharp increase in losses, or even thermal breakdown. Therefore, accurately predicting the extreme temperatures of various components within the controller is of great significance for controller structural design, heat dissipation design, safety margin assessment, and the formulation of thermal management strategies. Summary of the Invention
[0004] The purpose of this invention is to establish a multi-physics domain controller limit temperature estimation method based on parameter transfer, addressing the difficulty of achieving efficient and accurate coupling in situations where the time scales of multiple physical domains (electromagnetic, thermal, fluid, etc.) are inconsistent. Since the limit temperatures of components such as power devices, capacitors, and busbars within the controller directly affect the system's safety margin and reliability, accurate prediction is required under the influence of real electromagnetic parasitic parameters, loss mechanisms, and temperature fields. However, power devices have extremely high switching frequencies, rapid transient changes in the electromagnetic domain, and slow thermal responses; direct full coupling would result in a massive amount of simulation computation and compromised accuracy. This invention, through the transfer of key parameters across physical domains, separates and iteratively updates temperature- and frequency-related parasitic parameters, electrical characteristics, and losses according to time scales, achieving rapid convergence of the multi-physics domain temperature field. This allows for accurate estimation of the limit temperatures of various components in the controller and improves the reliability of system design and thermal management.
[0005] To achieve the above objectives, this invention provides a method for estimating the limiting temperature of a multi-physics domain controller based on parameter transfer, comprising:
[0006] Based on the initial temperature and operating frequency of each component of the controller, the electrical parameters of the capacitor, the impedance parameters of the busbar, and the characteristic parameters of the power devices are obtained.
[0007] Based on the capacitor electrical parameters, busbar impedance parameters, and power device characteristic parameters, the current and resistance variables in the controller circuit are obtained.
[0008] Based on the current and resistance variables, the loss values of each component of the controller are obtained;
[0009] Based on the aforementioned loss values, the calculated temperatures of each component of the controller are obtained through fluid-structure interaction heat transfer calculations.
[0010] The difference between the calculated temperature and the initial temperature is compared with a preset threshold. When the difference is not less than the preset threshold, the calculated temperature is used as the new initial temperature for iterative calculation until the difference is less than the preset threshold. Then, the limit temperature of each component of the controller is output.
[0011] Preferably, the initial temperature includes the initial temperature of the capacitor, the initial temperature of the DC input bus, the initial temperature of the DC output bus, and the initial temperature of the power device;
[0012] The operating frequency includes the controller's operating frequency.
[0013] Preferably, the electrical parameters of the capacitor include the capacitance value and the equivalent resistance of the capacitor;
[0014] The capacitance value is obtained based on the capacitor's initial temperature and the controller's operating frequency using a capacitor temperature-frequency characteristic model.
[0015] The equivalent resistance of the capacitor is obtained by using the temperature-frequency characteristic model of the equivalent resistance of the capacitor, based on the initial temperature of the capacitor and the operating frequency of the controller.
[0016] Preferably, the busbar impedance parameters include DC busbar resistance, DC busbar stray inductance, AC busbar upper arm stray inductance, and AC busbar lower arm stray inductance.
[0017] The DC bus resistance and the DC bus stray inductance are obtained based on the initial temperature of the DC input bus and the operating frequency of the controller.
[0018] Based on the initial temperature of the power devices and the operating frequency of the controller, the stray inductance of the upper arm of the AC busbar and the stray inductance of the lower arm of the AC busbar are obtained.
[0019] Preferably, the power device characteristic parameters include power device turn-on characteristic parameters, turn-off characteristic parameters, and internal resistance parameters;
[0020] Based on the initial temperature of the power device, the conduction characteristic parameters, turn-off characteristic parameters, and internal resistance parameters of the power device are obtained through a power device temperature characteristic fitting model.
[0021] Preferably, the current variables include the current flowing through the capacitor, the current flowing through the DC bus, and the bridge arm current flowing through the power device.
[0022] The capacitor electrical parameters, busbar impedance parameters, and power device characteristic parameters are input into the controller circuit model, and the controller circuit model is coupled to the traction motor control model.
[0023] Based on the coupled calculation of the controller circuit model and the traction motor control model, the current flowing through the capacitor, the current flowing through the DC bus, and the bridge arm current flowing through the power device are obtained.
[0024] Preferably, the loss values include capacitor loss, DC bus loss, and power device loss;
[0025] The capacitor loss is obtained based on the current flowing through the capacitor and the equivalent resistance of the capacitor.
[0026] The DC bus loss is obtained based on the current flowing through the DC bus and the DC bus resistance.
[0027] The power device losses are obtained based on the bridge arm current and the characteristic parameters of the power devices.
[0028] Preferably, the calculated temperature includes capacitor temperature, DC bus temperature, and power device temperature;
[0029] Input capacitor loss, DC bus loss and power device loss into the temperature calculation model of the fluid-structure interaction controller;
[0030] The capacitor temperature, DC bus temperature, and power device temperature are obtained based on the temperature calculation model of the fluid-structure interaction controller.
[0031] Preferably, the iterative calculation process includes:
[0032] The temperature deviation value is obtained by calculating the difference between the calculated temperature and the corresponding initial temperature.
[0033] The absolute value of the temperature deviation is compared with the preset threshold.
[0034] When the absolute value is not less than the preset threshold, the calculated temperature is used as the new initial temperature, the capacitor electrical parameters, busbar impedance parameters and power device characteristic parameters are updated, and the subsequent calculation steps are re-executed.
[0035] Preferably, the components of the controller include a supporting capacitor, a positive input DC busbar, a negative output DC busbar, a U-phase upper bridge arm power device, a U-phase lower bridge arm power device, a V-phase upper bridge arm power device, a V-phase lower bridge arm power device, a W-phase upper bridge arm power device, and a W-phase lower bridge arm power device.
[0036] The extreme temperature is obtained by comparing the output temperatures of each component of the controller with their corresponding safety thresholds.
[0037] Compared with the prior art, the present invention has the following advantages and technical effects:
[0038] This invention achieves complete coupled analysis of the electromagnetic and thermal multi-physics domains by constructing a parameter transfer chain of "initial temperature / operating frequency → electrical parameters → current / resistance variables → loss values → fluid-structure interaction heat transfer → iterative convergence". This transforms the limit temperature estimation from a traditional fixed parameter model to a dynamic coupled model, significantly improving the simulation accuracy and computational reliability of thermal safety design for high power density controllers.
[0039] This invention provides accurate initial boundary conditions for the entire estimation system by clearly distinguishing the initial temperature into capacitor temperature, DC input / output busbar temperature and power device temperature, and introducing the controller operating frequency as the core input variable, ensuring that subsequent calculations are based on actual operating parameters rather than empirical assumptions.
[0040] This invention dynamically obtains the capacitance value and equivalent resistance by inputting the initial temperature and operating frequency of the capacitor into the capacitor temperature-frequency characteristic model, so that the calculation of capacitor electrical parameters has temperature-frequency dual dependence characteristics, accurately reflecting the influence mechanism of capacitor performance degradation on system loss under high temperature and high frequency.
[0041] This invention achieves dynamic calculation of busbar parasitic parameters as temperature rises by inputting the initial busbar temperature and operating frequency into the busbar electrical parameter calculation module, thereby obtaining the DC busbar resistance / stray inductance and the AC busbar bridge arm stray inductance. This solves the problem of loss estimation deviation caused by constant busbar parameters in traditional models.
[0042] This invention obtains the on / off characteristic parameters and internal resistance parameters by fitting a temperature characteristic model to the initial temperature input of the power device, and establishes a functional mapping relationship between the device switching behavior and the junction temperature, providing a model basis for accurately calculating the device loss degradation caused by temperature rise.
[0043] This invention obtains the real-time current variables flowing through the capacitor, busbar, and inverter bridge arm by inputting the capacitor's electrical parameters, busbar's electrical parameters, and power device characteristic parameters into the controller circuit model and coupling them with the traction motor control model for calculation, thereby realizing the co-simulation of circuit topology and motor load.
[0044] This invention calculates capacitor loss, DC bus loss, and power device loss of each bridge arm of the inverter by inputting the current variable and the corresponding resistance / characteristic parameters into the loss calculation module. This achieves refined classification and quantitative decomposition of loss sources, providing accurate heat source distribution data for thermal analysis.
[0045] This invention achieves electrothermal coupling heat transfer analysis by inputting various loss values into the temperature calculation model of the fluid-structure interaction controller, dynamically obtaining the capacitor temperature, DC bus temperature and power device temperature, and obtaining the temperature field distribution characteristics of each key component inside the controller.
[0046] This invention achieves rapid convergence and adaptive accuracy control of the calculation process by comparing the difference between the calculated temperature and the initial temperature with a preset threshold, and iteratively updating the calculated temperature as a new initial value when the difference is not less than the threshold, until the difference is less than the threshold.
[0047] This invention identifies the supporting capacitor, DC bus, and the six bridge arm power devices of the inverter as the objects of temperature estimation, and compares the final output temperature of each component with its safety threshold, thereby achieving targeted prediction of the extreme temperature of key components of the controller and quantitative assessment of the safety margin. Attached Figure Description
[0048] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:
[0049] Figure 1 This is a schematic diagram of the method flow according to an embodiment of the present invention;
[0050] Figure 2This is a schematic diagram of the controller circuit model coupled to the traction motor control module in an embodiment of the present invention;
[0051] Figure 3 This is a graph showing the relationship between a certain capacitor parameter and temperature and operating frequency according to an embodiment of the present invention;
[0052] Figure 4 This is a graph showing the relationship between the equivalent resistance of a capacitor and temperature and operating frequency in an embodiment of the present invention.
[0053] Figure 5 This is a graph showing the relationship between the stray inductance of the DC input bus and temperature and operating frequency in an embodiment of the present invention.
[0054] Figure 6 This is a graph showing the relationship between the DC input busbar resistance, temperature, and operating frequency in an embodiment of the present invention. Detailed Implementation
[0055] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0056] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.
[0057] like Figure 1 As shown, to address the current problem of multi-physics domain coupled temperature analysis in controllers, this embodiment provides a method for estimating the limit temperature of multi-physics domain controllers based on parameter transfer, including:
[0058] Based on the initial temperature and operating frequency of each component of the controller, the electrical parameters of the capacitor, the impedance parameters of the busbar, and the characteristic parameters of the power devices are obtained.
[0059] Based on the capacitor electrical parameters, busbar impedance parameters, and power device characteristic parameters, the current and resistance variables in the controller circuit are obtained.
[0060] Based on the current and resistance variables, the loss values of each component of the controller are obtained;
[0061] Based on the loss values, the calculated temperatures of each component of the controller are obtained through fluid-structure interaction heat transfer calculations.
[0062] The difference between the calculated temperature and the initial temperature is compared with a preset threshold. When the difference is not less than the preset threshold, the calculated temperature is used as the new initial temperature for iterative calculation until the difference is less than the preset threshold. Then, the limit temperature of each component of the controller is output.
[0063] Furthermore, the initial temperature includes the initial temperature of the capacitor, the initial temperature of the DC input busbar, the initial temperature of the DC output busbar, and the initial temperature of the power devices;
[0064] Operating frequency includes the controller's operating frequency.
[0065] Furthermore, the electrical parameters of a capacitor include its capacitance value and its equivalent resistance.
[0066] The capacitance value is obtained by using the capacitor temperature-frequency characteristic model based on the capacitor's initial temperature and the controller's operating frequency.
[0067] Based on the initial temperature of the capacitor and the operating frequency of the controller, the equivalent resistance of the capacitor is obtained through the temperature-frequency characteristic model of the equivalent resistance of the capacitor.
[0068] Furthermore, the busbar impedance parameters include DC busbar resistance, DC busbar stray inductance, AC busbar upper arm stray inductance, and AC busbar lower arm stray inductance.
[0069] The DC bus resistance and DC bus stray inductance are obtained based on the initial temperature of the DC input bus and the operating frequency of the controller.
[0070] Based on the initial temperature of the power devices and the operating frequency of the controller, the stray inductance of the upper arm of the AC busbar and the stray inductance of the lower arm of the AC busbar are obtained.
[0071] Furthermore, the characteristic parameters of power devices include power device turn-on characteristic parameters, turn-off characteristic parameters, and internal resistance parameters;
[0072] Based on the initial temperature of the power device, the on-state characteristic parameters, off-state characteristic parameters, and internal resistance parameters of the power device are obtained through a power device temperature characteristic fitting model.
[0073] Furthermore, the current variables include the current flowing through the capacitor, the current flowing through the DC bus, and the bridge arm current flowing through the power devices.
[0074] The capacitor electrical parameters, busbar impedance parameters, and power device characteristic parameters are input into the controller circuit model, and the controller circuit model is coupled with the traction motor control model.
[0075] Based on the coupled calculation of the controller circuit model and the traction motor control model, the current flowing through the capacitor, the current flowing through the DC bus, and the bridge arm current flowing through the power device are obtained.
[0076] Furthermore, the loss figures include capacitor losses, DC bus losses, and power device losses.
[0077] The capacitor loss is obtained based on the current flowing through the capacitor and the capacitor's equivalent resistance.
[0078] The DC bus losses are obtained based on the current flowing through the DC bus and the DC bus resistance.
[0079] The power device losses are obtained based on the bridge arm current and the characteristic parameters of the power devices.
[0080] Furthermore, the calculated temperatures include capacitor temperature, DC bus temperature, and power device temperature;
[0081] Input capacitor loss, DC bus loss and power device loss into the temperature calculation model of the fluid-structure interaction controller;
[0082] Based on the temperature calculation model of the fluid-structure interaction controller, the capacitor temperature, DC bus temperature, and power device temperature are obtained.
[0083] Furthermore, the iterative calculation process includes:
[0084] The temperature deviation value is obtained by calculating the difference between the calculated temperature and the corresponding initial temperature.
[0085] Compare the absolute value of the temperature deviation with a preset threshold.
[0086] When the absolute value is not less than the preset threshold, the calculated temperature is used as the new initial temperature, the capacitor electrical parameters, busbar impedance parameters and power device characteristic parameters are updated, and the subsequent calculation steps are re-executed.
[0087] Furthermore, the controller components include a support capacitor, a positive input DC busbar, a negative output DC busbar, a U-phase upper bridge arm power device, a U-phase lower bridge arm power device, a V-phase upper bridge arm power device, a V-phase lower bridge arm power device, a W-phase upper bridge arm power device, and a W-phase lower bridge arm power device.
[0088] The extreme temperature is obtained by comparing the output temperature of each component of the controller with its corresponding safety threshold.
[0089] Furthermore, the technical solution adopted in this embodiment is as follows: This method is based on a controller circuit model coupled with a traction motor control circuit calculation module, and includes several major components such as a capacitor parameter module related to temperature and operating frequency, a busbar stray inductance and resistance calculation module, a power device behavior module, a loss calculation module, and a fluid-structure interaction controller calculation and simulation module. It achieves the controller temperature measurement function in the electromagnetic-thermal multi-physics domain through a time-stepping method, such as... Figure 1 As shown.
[0090] The busbar resistance and stray inductance module is based on a 3D model. Electromagnetic coupling analysis is performed using electromagnetic finite element simulation software. By setting material properties at different temperatures, the busbar resistance and stray inductance values are simulated under different temperatures, input current magnitudes, and frequencies. Regression analysis is used to analyze the busbar resistance and stray inductance, including the stray inductance L of the positive input DC busbar. b1 Positive input DC busbar resistance R b1 Negative output DC bus stray inductance L b2 Negative output DC busbar resistance R b2 AC U-phase busbar upper arm stray inductance L b21 AC U-phase busbar lower arm stray inductance L b24 AC V-phase busbar upper arm stray inductance L b23 AC V-phase busbar lower arm stray inductance L b26 stray inductance L on the upper arm of the W-phase busbar b25 stray inductance L of the lower arm of the AC busbar b22 .
[0091] The power device behavior module establishes a functional model of the relationship between the power device's on / off characteristic parameters, internal resistance, and temperature using fitting analysis based on the main characteristics of the selected power device.
[0092] The controller circuit model coupled with the traction motor control module is a circuit model, such as... Figure 2 As shown, its controller circuit model can be a typical three-phase inverter circuit model, where each power module is a power device behavior module. Its on / off characteristic parameters and internal resistance parameters are affected by the power device temperature. The model includes a capacitor equivalent circuit model and nested capacitor parameter modules, ensuring that the capacitance value C and equivalent series inductance L in the capacitor equivalent circuit are... c Equivalent series resistance R c The resistance varies with the input capacitor temperature and operating frequency. The busbar resistance and stray inductance values are obtained through a busbar resistance and stray inductance calculation module, varying with temperature at different busbar locations and the magnitude and frequency of the input current. The motor model is an equivalent circuit resistance-inductance model. The motor can be nested with vector control or direct torque control. Pulse width modulation can be achieved using Voltage Vector Pulse Width Modulation (SVPWM) to form an SVPWM control module. When the motor needs to output under certain operating conditions, including the required torque and speed, the SVPWM control module performs closed-loop control of the inverter circuit, ultimately obtaining the current response of each part of the control circuit, including the real-time current i flowing through the capacitor. c The current i flowing through the DC busbar bus The current i flowing through the 6 bridge arms of the inverter VT1 i VT2 i VT3 iVT4 i VT5 i VT6 .
[0093] The loss module calculates the capacitor loss p in the equivalent circuit of the output capacitor based on the circuit current and resistance variables in the traction motor control model coupled with the controller circuit module. c The positive input DC busbar loss p in the busbar resistance and stray inductance b1 Negative output DC bus loss p b2 The power device loss p in the upper arm of the U-phase in the inverter circuit VT1 U-phase lower arm power device loss p VT4 V-phase upper arm power device loss p VT3 V-phase lower arm power device loss p VT6 The power device loss p of the upper bridge arm of the W phase VT5 The power device loss p in the lower arm of the W phase VT2 .
[0094] The fluid-structure interaction (FSI) controller temperature calculation module is based on a 3D model and uses finite element simulation software to calculate the temperature values of each component of the controller, including the capacitor temperature T. c Positive input DC busbar temperature T b1 Negative output DC bus temperature T b2 And the temperature T of the upper arm power device of the U phase in the inverter circuit. VT1 Temperature T of the power device in the lower U-phase bridge arm VT4 Temperature T of the power device on the upper arm of phase V VT3 Temperature T of the power device in the lower V-phase bridge arm VT6 Temperature T of the power device on the upper arm of phase W VT5 Temperature T of the power device in the lower arm of the W phase VT2 .
[0095] As a preferred implementation method, for example, Figure 1 As shown, the multi-physics domain controller temperature calculation method comprises: a capacitor parameter module, a busbar resistance and stray inductance calculation module, a power device behavior module, a loss calculation module, and a fluid-structure interaction controller temperature calculation module.
[0096] The specific implementation process includes:
[0097] (1) First, set the system to work under certain conditions, estimate the initial operating conditions and enter the initial operating condition module. The initial operating conditions include the effective value of the current required by the traction motor I and the current frequency f1, the operating frequency f2 of the power devices, and the initial temperatures of each part of the controller, including the capacitor temperature T. c DC input busbar temperature T b1DC output busbar temperature T b2 Temperature T of the power device on the upper arm of the U-phase bridge VT1 Temperature T of the power device in the lower U-phase bridge arm VT4 Temperature T of the power device on the upper arm of phase V VT3 Temperature T of the power device in the lower V-phase bridge arm VT6 Temperature T of the power device on the upper arm of phase W VT5 Temperature T of the power device in the lower arm of the W phase VT2 That is, the temperature T of each arm of the inverter. VT1-6 When the power device operates at frequency f2, the capacitor temperature T c The input capacitor parameter module outputs the capacitance value C and the equivalent series inductance L under this operating condition. c Equivalent series resistance R c If a certain film capacitor is used, its rated capacitance is 45. Its capacitance C is related to the capacitor temperature T c The relationship with the operating frequency f2 is as follows: Figure 3 As shown; its equivalent resistance R c With capacitor temperature T c The relationship with the operating frequency f2 is as follows: Figure 4 As shown.
[0098] The regression function of capacitance value with temperature and operating frequency is as follows:
[0099] The regression function of the equivalent resistance of the capacitor with respect to temperature and operating frequency is as follows:
[0100]
[0101] (2) When the initial temperature T of the initial DC input busbar b1 DC output bus initial temperature T b2 Power device temperature T VT1-6 The operating frequency f2 of the power device is input to the busbar resistance and stray inductance calculation module, which outputs the stray inductance L of the positive input DC busbar under this operating condition. b1 Positive input DC busbar resistance R b1 Negative output DC bus stray inductance L b2 Negative output DC busbar resistance R b2 AC U-phase busbar upper arm stray inductance L b21 AC U-phase busbar lower arm stray inductance L b24 AC V-phase busbar upper arm stray inductance L b23 AC V-phase busbar lower arm stray inductance L b26 stray inductance L on the upper arm of the W-phase busbar b25 stray inductance L of the lower arm of the AC busbar b22If the DC bus stray inductance L is obtained... b1 With the initial temperature T of the DC input busbar b1 The relationship between the power device frequency f2 is as follows: Figure 5 As shown. DC input busbar resistance R b1 With DC input busbar temperature T b1 The relationship between the operating frequency f2 of power devices is as follows: Figure 6 As shown.
[0102] (3) When the initial temperature T of the device VT1-6 The operating frequency f2, the effective value of the current I, and the current frequency f1 of the power device are input to the power device behavior module. The power device behavior module outputs the power device's turn-on and turn-off characteristic parameters and internal resistance to the controller circuit model, which is coupled to the traction motor control module. The controller circuit model, coupled to the traction motor control module, outputs the effective value of the input current I and the current frequency f1 of the power device to the power device behavior module in real time for data interaction.
[0103] (4) The controller circuit model couples the traction motor control module with the capacitor parameter module to obtain the parameter values of the equivalent circuit of the capacitor, the busbar resistance and stray inductance values from the busbar resistance and stray inductance calculation module, and the conduction and turn-off characteristic parameters and internal resistance parameters of a single power device through the power device behavior module. The motor model is an equivalent circuit resistance and inductance model. The motor can be nested with vector control or direct torque control. The pulse width modulation can be composed of voltage vector pulse width modulation (SVPWM) to form an SVPWM control module. When the motor needs to output under certain operating conditions, including the required torque and speed, the inverter circuit is closed-loop controlled through the SVPWM control module, and finally the current response of each part of the control circuit is obtained, including the real-time current i flowing through the capacitor. c The current i flowing through the DC busbar bus The current i flowing through the 6 bridge arms of the inverter VT1 i VT2 i VT3 i VT4 i VT5 i VT6 .
[0104] (5) The loss calculation module calculates the capacitor loss P in the output capacitor equivalent circuit based on the capacitor equivalent circuit, busbar circuit, power device current and resistance variables in the controller circuit module coupled to the traction motor control model. c The positive input DC busbar loss P in the busbar resistance and stray inductance b1 Negative output DC bus loss P b2 The power device loss P in the upper arm of the U-phase of the inverter circuit VT1 U-phase lower arm power device loss P VT4 V-phase upper arm power device loss PVT3 V-phase lower arm power device loss P VT6 The power device loss P in the upper arm of the W phase VT5 The power device loss P in the lower bridge arm of the W phase VT2 These losses are output to the temperature calculation module of the fluid-structure interaction controller.
[0105] (6) The temperature calculation module of the fluid-structure interaction controller is based on a 3D model and uses finite element simulation software for fluid-structure interaction to calculate the temperature values of each component, wherein the loss input loss is the output of the loss calculation module. The temperature values of each component of the controller, including the capacitor temperature T, are calculated using the finite element simulation software for fluid-structure interaction. cj Positive input DC busbar temperature T b1j Negative output DC bus temperature T b2j And the temperature T of the upper arm power device of the U phase in the inverter circuit. VT1j Temperature T of the power device in the lower U-phase bridge arm VT4j Temperature T of the power device on the upper arm of phase V VT3j Temperature T of the power device in the lower V-phase bridge arm VT6j Temperature T of the power device on the upper arm of phase W VT5j Temperature T of the power device in the lower arm of the W phase VTj2 Due to the different locations and wear conditions of various parts within the controller, their temperatures will differ. The difference between the calculated temperature of each part and the initial given temperature is calculated as ΔT. When ΔT < ε, the temperature of each part of the controller is output. When ΔT > ε, the calculated temperature obtained from the fluid-structure interaction controller temperature calculation module is used as the initial value and input into the initial operating condition module to update the temperature of each component. This process is repeated until ΔT < ε, at which point the temperature of each part of the controller is output. The value of ε can be set according to the different temperature estimation accuracies of the system. Finally, by comparing the calculated temperature with the component safety threshold, the limit temperature and safety margin of the controller's key components are obtained.
[0106] This embodiment breaks away from the traditional electromagnetic-circuit-thermal strongly coupled simulation approach, which suffers from high computational complexity and low convergence, and achieves collaborative solution across physical domains at different time scales. Specifically, this embodiment dynamically exchanges the parasitic inductance, resistance, equivalent parameters, and device behavior characteristics of key components such as capacitors, busbars, and power devices under temperature and frequency conditions through parameter transfer between the electromagnetic, circuit, and thermo-fluid-structure interaction domains. A weakly coupled multi-physics domain computational framework is constructed through time-step iteration. This framework maintains a true reflection of electromagnetic transients on parasitic parameters while significantly improving the efficiency of steady-state solutions in the thermal domain. Based on this, the invention enables the prediction of the extreme temperatures of components such as capacitors, busbars, and power devices within the controller, transforming parasitic parameter and temperature rise calculations from fixed-parameter models to dynamic models that are temperature- and frequency-dependent. This overcomes the limitations of existing technologies that struggle to simultaneously achieve simulation accuracy and computability, providing a new technical path for the thermal safety design, life assessment, and structural optimization of high-power-density motor controllers.
[0107] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A method for estimating the limiting temperature of a multi-physics domain controller based on parameter transfer, characterized in that, include: Based on the initial temperature and operating frequency of each component of the controller, the electrical parameters of the capacitor, the impedance parameters of the busbar, and the characteristic parameters of the power devices are obtained. Based on the capacitor electrical parameters, busbar impedance parameters, and power device characteristic parameters, the current and resistance variables in the controller circuit are obtained. Based on the current and resistance variables, the loss values of each component of the controller are obtained; Based on the aforementioned loss values, the calculated temperatures of each component of the controller are obtained through fluid-structure interaction heat transfer calculations. The difference between the calculated temperature and the initial temperature is compared with a preset threshold. When the difference is not less than the preset threshold, the calculated temperature is used as the new initial temperature for iterative calculation until the difference is less than the preset threshold. Then, the limit temperature of each component of the controller is output.
2. The method according to claim 1, characterized in that, The initial temperature includes the initial temperature of the capacitor, the initial temperature of the DC input busbar, the initial temperature of the DC output busbar, and the initial temperature of the power devices; The operating frequency includes the controller's operating frequency.
3. The method according to claim 1, characterized in that, The electrical parameters of the capacitor include the capacitance value and the equivalent resistance of the capacitor; The capacitance value is obtained based on the capacitor's initial temperature and the controller's operating frequency using a capacitor temperature-frequency characteristic model. The equivalent resistance of the capacitor is obtained by using the temperature-frequency characteristic model of the equivalent resistance of the capacitor, based on the initial temperature of the capacitor and the operating frequency of the controller.
4. The method according to claim 1, characterized in that, The busbar impedance parameters include DC busbar resistance, DC busbar stray inductance, AC busbar upper arm stray inductance, and AC busbar lower arm stray inductance. The DC bus resistance and the DC bus stray inductance are obtained based on the initial temperature of the DC input bus and the operating frequency of the controller. Based on the initial temperature of the power devices and the operating frequency of the controller, the stray inductance of the upper arm of the AC busbar and the stray inductance of the lower arm of the AC busbar are obtained.
5. The method according to claim 1, characterized in that, The power device characteristic parameters include the power device's turn-on characteristic parameters, turn-off characteristic parameters, and internal resistance parameters. Based on the initial temperature of the power device, the conduction characteristic parameters, turn-off characteristic parameters, and internal resistance parameters of the power device are obtained through a power device temperature characteristic fitting model.
6. The method according to claim 1, characterized in that, The current variables include the current flowing through the capacitor, the current flowing through the DC bus, and the bridge arm current flowing through the power device. The capacitor electrical parameters, busbar impedance parameters, and power device characteristic parameters are input into the controller circuit model, and the controller circuit model is coupled to the traction motor control model. Based on the coupled calculation of the controller circuit model and the traction motor control model, the current flowing through the capacitor, the current flowing through the DC bus, and the bridge arm current flowing through the power device are obtained.
7. The method according to claim 1, characterized in that, The loss values include capacitor loss, DC bus loss, and power device loss. The capacitor loss is obtained based on the current flowing through the capacitor and the equivalent resistance of the capacitor. The DC bus loss is obtained based on the current flowing through the DC bus and the DC bus resistance. The power device losses are obtained based on the bridge arm current and the characteristic parameters of the power devices.
8. The method according to claim 1, characterized in that, The calculated temperatures include capacitor temperature, DC bus temperature, and power device temperature. Input capacitor loss, DC bus loss and power device loss into the temperature calculation model of the fluid-structure interaction controller; The capacitor temperature, DC bus temperature, and power device temperature are obtained based on the temperature calculation model of the fluid-structure interaction controller.
9. The method according to claim 1, characterized in that, The iterative calculation process includes: The temperature deviation value is obtained by calculating the difference between the calculated temperature and the corresponding initial temperature. The absolute value of the temperature deviation is compared with the preset threshold. When the absolute value is not less than the preset threshold, the calculated temperature is used as the new initial temperature, the capacitor electrical parameters, busbar impedance parameters and power device characteristic parameters are updated, and the subsequent calculation steps are re-executed.
10. The method according to claim 1, characterized in that, The controller components include a support capacitor, a positive input DC busbar, a negative output DC busbar, a U-phase upper bridge arm power device, a U-phase lower bridge arm power device, a V-phase upper bridge arm power device, a V-phase lower bridge arm power device, a W-phase upper bridge arm power device, and a W-phase lower bridge arm power device. The extreme temperature is obtained by comparing the output temperatures of each component of the controller with their corresponding safety thresholds.