Junction temperature estimation method and system for power module in motor controller

Abstract

The invention provides a junction temperature estimation method and system for a power module in a motor controller. The method comprises the following steps: S1, acquiring working condition data and power module parameters of a whole vehicle; s2, adjusting a pre-calibrated equivalent coupling thermal impedance matrix parameter and a chip thermal resistance parameter according to the coolant flow signal, and respectively calculating the total transient loss power in the switching period of different switching tubes in the same phase according to the working condition data and the power module parameter; estimating the water temperature according to the temperature of the module temperature sensor, the total transient loss power and the equivalent coupling thermal impedance matrix of different switch tubes to the module temperature sensor; and S3, calculating the junction temperature rise of the chip, calculating the estimated junction temperature of the chip according to the junction temperature rise and the estimated water temperature, and feeding back the estimated junction temperature of the chip to the step S1 for querying the module conduction voltage drop and switching loss parameters in the next period. The invention aims to realize high-precision real-time estimation of the junction temperature of the power module of the motor controller in a full working condition range.

Description

Technical Field

[0001] This invention relates to the field of motor controller technology, and in particular to a method and system for estimating the junction temperature of a power module in a motor controller. Background Technology

[0002] In the powertrain system of electric vehicles, the motor controller plays a crucial role, and its reliability directly determines the operational stability of the entire vehicle. As one of the core components of the motor controller, the IGBT (Insulated Gate Bipolar Transistor) is the main path for current conversion, and its performance directly affects key indicators such as the vehicle's power output and energy consumption control. Therefore, it occupies an irreplaceable position in the electric vehicle powertrain system.

[0003] However, electric vehicles face extremely complex operating conditions in real-world use. Changes in altitude affect atmospheric pressure, thus altering the heat dissipation environment; significant differences in ambient temperature across different regions and seasons pose challenges to the thermal management of power modules; and complex and variable road conditions (such as urban congestion, highway driving, and hill climbing) cause drastic fluctuations in the load on power modules, resulting in substantial changes in heat generation. The combined effect of these external conditions makes the operating conditions of power modules highly complex, severely testing their reliability. Numerous studies have shown that the reliability of power modules is closely related to their junction temperature. Excessively high junction temperatures accelerate device aging, shorten lifespan, and may even lead to instantaneous device failure, causing vehicle malfunctions; while inaccurate junction temperature estimation can cause thermal management strategies to fail, failing to effectively protect the power module. Therefore, how to accurately and in real-time estimate the junction temperature of power modules has become one of the key technical issues in ensuring the reliability of electric vehicle power systems.

[0004] Currently, research on power module junction temperature estimation has been conducted in related fields, and some technical solutions have been developed. For example, Chinese patent application CN117214670A discloses a method for determining the temperature of a power module, a motor controller, and a vehicle. This solution collects the water temperature in real time by arranging a temperature sensor in the controller's water channel, compares it with the temperature of electronic components corresponding to a preset coolant flow rate, determines the current coolant flow rate based on the comparison result, and then adjusts the thermal impedance parameters between the chip and the electronic components based on this flow rate to calculate the chip junction temperature. However, this solution has significant limitations: it requires special processing of the water channel to place the temperature sensor, and it needs to be connected to the control board via a wiring harness to achieve signal transmission, which undoubtedly increases the complexity and cost of the manufacturing process; more importantly, this solution does not consider the power loss generated by each switching transistor under stall conditions as the angle changes, and this change will cause the thermal impedance parameters between the switching transistor and the electronic components to change, ultimately causing deviations in the junction temperature estimation.

[0005] Another Chinese patent application, CN119720501A, discloses a method and apparatus for estimating the junction temperature of power devices through thermal resistance parameter compensation. The core idea is to calculate the power loss value of the power device based on the operating conditions of the electric vehicle cooling system, input this loss value into a thermal resistance model to obtain the power thermal resistance parameter value, and then combine it with the coolant flow rate to calibrate the thermal resistance parameter compensation value. Finally, the junction temperature is estimated based on the power consumption thermal resistance parameter value and the thermal resistance compensation value. This scheme achieves thermal resistance correction by adjusting the thermal resistance parameter under different power consumption and flow rate conditions, thus improving the estimation accuracy to some extent. However, this scheme also has drawbacks: it does not consider the characteristics of the power loss of each switching transistor changing with the angle under stall conditions. At different stall angles, the heating of the corresponding chips varies significantly. Furthermore, due to the different layout positions of the module temperature sensors, the impact of different chip heating on the temperature sensor temperature rise during stall is different. Compensating for the thermal resistance parameter solely by the power loss value cannot compensate for the estimation error caused by the difference in sensor layout, still leading to inaccurate junction temperature estimation results. Summary of the Invention

[0006] The technical problem to be solved by this invention is: in view of the technical problems existing in the prior art, this invention provides a method and system for estimating the junction temperature of the power module in a motor controller. This invention aims to improve the accuracy of chip junction temperature estimation under different operating conditions.

[0007] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A method for estimating the junction temperature of a power module in a motor controller includes the following steps: Step S1: Obtain the vehicle's operating condition data and power module parameters. The operating condition data includes phase current and coolant flow signals. The power module parameters include module temperature sensor temperature, module on-state voltage drop, and module switching loss. The module on-state voltage drop and module switching loss are obtained by querying a pre-stored two-dimensional relationship mapping table based on the phase current and the junction temperature feedback value estimated in the previous cycle. Step S2: Adjust the equivalent coupling thermal impedance matrix parameters of different switching transistors in the same phase to the temperature sensor and the thermal resistance parameters from the chip to the coolant based on the pre-calibrated parameters of ... Step S3: Calculate the chip junction temperature rise based on the total transient power loss during the switching cycle of different switching transistors in the same phase and the thermal resistance from the chip to the coolant. Calculate the estimated junction temperature of the chip based on the junction temperature rise and the estimated water temperature, and feed the estimated junction temperature back to step S1 for querying the module on-state voltage drop and switching loss parameters in the next cycle.

[0008] Optionally, the equivalent coupling thermal impedance matrix is: , In the above formula, This represents the equivalent coupling thermal impedance matrix. This represents the equivalent thermal impedance of the upper IGBT to the temperature sensor. This represents the equivalent thermal impedance of the upper tube FRD to the temperature sensor. This represents the equivalent thermal impedance of the lower IGBT to the temperature sensor. This represents the equivalent thermal impedance of the lower tube FRD to the temperature sensor.

[0009] Optionally, methods for adjusting the equivalent coupling thermal impedance matrix parameters of different switching transistors to the temperature sensor based on the coolant flow signal include: Step S201: Conduct experiments or simulations under different coolant flow conditions. By applying known loss excitations to different switching transistors, simulate the heat loss of the switching transistors in actual operation. Step S202: After applying the loss excitation, the resistance change of the temperature sensor is collected, and the influence of different switching transistors on the temperature rise of the temperature sensor is recorded by referring to the temperature-resistance relationship table. Step S203: Based on the measured temperature rise of each switching transistor to the module temperature sensor and the known loss excitation, calculate the equivalent coupling thermal impedance of different switching transistors to the module temperature sensor, and form an equivalent coupling thermal impedance matrix. The equivalent coupling thermal impedance is calculated as follows: , In the formula, This represents the equivalent thermal impedance of the switching transistor i to the temperature sensor. Pi represents the temperature change of the temperature sensor; Pi represents the power loss of the switching transistor i.

[0010] Optionally, in step S2, the method for estimating the water temperature based on the temperature of the module temperature sensor, the total transient power loss during the switching cycles of different switches in the same phase, and the equivalent coupling thermal impedance matrix of different switches to the module temperature sensor includes: Step S211: Obtain the actual temperature of the module sensor and calculate the total transient power loss during the cycle of each switch; Step S212: Determine the heating location of the switching transistor in the same phase according to the positive and negative relationship of the phase current. When the phase current is positive, the upper IGBT switching transistor and the lower FRD switching transistor are heating. When the phase current is negative, the lower IGBT switching transistor and the upper FRD switching transistor are heating. The power of the switching transistor that does not heat up is recorded as 0. Step S213, based on the equivalent coupling thermal impedance matrix The temperature rise of the module temperature sensor is calculated by linear superposition of the total transient power loss of the heating switch tube during each switching cycle according to the following formula: , In the above formula, This indicates the temperature rise of the module's temperature sensor. This represents the equivalent coupling thermal impedance matrix of different switching transistors to the module's temperature sensor. This indicates the power loss of the upper IGBT. This indicates the power loss of the upper tube FRD; This indicates the power loss of the lower IGBT. This indicates the power loss of the lower tube FRD; Step S214: Estimate the water temperature using the following formula based on the cooling water temperature rise and the actual temperature of the module sensor: , In the above formula, This indicates an estimate of the water temperature. Indicates the temperature of the module's temperature sensor. This indicates the temperature rise of the module's temperature sensor.

[0011] Optionally, in step S2, the total transient power loss during the switching cycle of different switches in the same phase includes chip conduction power loss and chip switching power loss. The chip conduction power loss is calculated based on the phase current, duty cycle and module conduction voltage drop in the operating data, and the chip switching power loss is calculated based on the bus voltage, phase current, switching frequency and module switching loss in the operating data.

[0012] Optionally, when the chip switching transistor is an IGBT, the functional expression for the chip's conduction loss power is: , In the above formula, This indicates the IGBT conduction loss power. This indicates the on-state voltage drop of the module. Indicates the IGBT on-state current. Indicates the duty cycle; The functional expression for the switching power loss of the chip is: , In the above formula, This indicates the switching power loss of the IGBT. Indicates the IGBT switching frequency. Indicates module activation loss. Indicates module shutdown loss. Indicates bus voltage. This represents the reference voltage.

[0013] Optionally, when the chip switch is an FRD, the functional expression for the chip's conduction loss power is: , In the above formula, This indicates the conduction loss power of the FRD. This indicates the on-state voltage drop of the module. Indicates the freewheeling current of the FRD. Indicates the duty cycle; The functional expression for the switching power loss of the chip is: , In the above formula, This indicates the power loss of the FRD switch. Indicates the FRD switching frequency. This represents the reverse recovery loss of the FRD. Indicates bus voltage. This represents the reference voltage.

[0014] Optionally, in step S3, the junction temperature rise of the IGBT chip is calculated based on the total transient power loss during the switching cycles of different switching transistors in the same phase and the thermal resistance from the chip to the coolant; wherein, the functional expression for the junction temperature rise of the IGBT chip is: , In the above formula, This indicates the junction temperature rise of the IGBT chip. This indicates the thermal resistance from the IGBT chip to the coolant. This indicates the IGBT conduction loss power. This indicates the power loss of the IGBT switching mechanism. The functional expression for the junction temperature rise of the FRD chip is: , In the above formula, This indicates the junction temperature rise of the FRD chip. Indicates the thermal resistance from the FRD chip to the coolant. This indicates the conduction loss power of the FRD. This indicates the power loss of the FRD switch.

[0015] Optionally, the estimated junction temperature of the chip can be calculated using the following formula based on the chip junction temperature rise and the estimated water temperature: IGBT chip junction temperature estimation for: , In the above formula, This indicates an estimate of the water temperature. This indicates the junction temperature rise of the IGBT chip; FRD chip estimates junction temperature for: , In the above formula, This indicates the junction temperature rise of the FRD chip.

[0016] The present invention also provides a junction temperature estimation system for a power module in a motor controller, comprising a microprocessor and a memory interconnected thereto, wherein the microprocessor is programmed or configured to execute the junction temperature estimation method for the power module in the motor controller.

[0017] Compared with the prior art, the advantages of the present invention are as follows: 1. This invention effectively solves the core technical problem of insufficient accuracy in power module junction temperature estimation caused by multiple heat source coupling interference and drastic changes in thermal boundary conditions under harsh operating conditions such as motor stall and low speed. This is achieved by estimating the junction temperature through a dynamic closed-loop feedback mechanism, an equivalent coupling thermal impedance matrix, and adjusting the equivalent coupling thermal impedance matrix parameters of different switches to the temperature sensor based on pre-calibrated parameters and the thermal resistance parameters from the chip to the coolant according to the coolant flow signal.

[0018] 2. This invention, based on a pre-calibrated equivalent coupling thermal impedance matrix, calculates the transient power loss of each switching transistor and, according to the principle of linear superposition, obtains the temperature rise of the temperature sensor. The estimated water temperature is then obtained by subtracting the calculated temperature rise from the actual temperature collected by the sensor. This method is independent of specific operating conditions and only depends on which switching transistor is generating heat. This not only broadens the applicable operating range but also significantly improves the accuracy of water temperature estimation, effectively addressing complex and variable working environments.

[0019] 3. This invention compensates for the impact of junction temperature changes on the accuracy of loss calculation by feeding back the estimated junction temperature of the previous cycle to the current cycle and dynamically querying the on-state voltage drop and switching loss parameters of the module, thus ensuring the accuracy of the core heat source calculation. By dynamically adjusting the thermal impedance model parameters according to the coolant flow signal, the thermal model can adapt to changes in different heat dissipation conditions. Attached Figure Description

[0020] Figure 1 This is a flowchart of the junction temperature estimation method for the power module in the motor controller in an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figure 1 As shown, this embodiment provides a method for estimating the junction temperature of a power module in a motor controller, including the following steps: Step S1: Obtain the vehicle's operating condition data and power module parameters. The operating condition data includes phase current and coolant flow signals. The power module parameters include module temperature sensor temperature, module on-state voltage drop, and module switching loss. The module on-state voltage drop and module switching loss are obtained by querying a pre-stored two-dimensional relationship mapping table based on the phase current and the junction temperature feedback value estimated in the previous cycle. Step S2: Adjust the equivalent coupling thermal impedance matrix parameters of different switching transistors in the same phase to the temperature sensor and the thermal resistance parameters from the chip to the coolant based on the pre-calibrated parameters of the coolant flow signal. Calculate the total transient power loss during the switching cycle of different switching transistors in the same phase based on the operating data and power module parameters. Estimate the water temperature based on the module temperature sensor temperature, the total transient power loss during the switching cycle of different switching transistors in the same phase, and the equivalent coupling thermal impedance matrix of different switching transistors to the module temperature sensor. Step S3: Calculate the junction temperature rise of the chip based on the total transient power loss during the switching cycle of different switching transistors in the same phase and the thermal resistance from the chip to the coolant. Calculate the estimated junction temperature of the chip based on the junction temperature rise and the estimated water temperature, and feed the estimated junction temperature of the chip back to step S1 for querying the module on-state voltage drop and switching loss parameters in the next cycle.

[0023] In specific application embodiments, the acquired vehicle operating condition data and module data include bus voltage, phase current, switching frequency, duty cycle, motor speed, flow signal, module temperature sensor temperature, module conduction voltage drop, and module switching loss.

[0024] In this embodiment, the equivalent coupling thermal impedance matrix is: (1) In the above formula, This represents the equivalent coupling thermal impedance matrix. This represents the equivalent thermal impedance of the upper IGBT to the temperature sensor. This represents the equivalent thermal impedance of the upper tube FRD to the temperature sensor. This represents the equivalent thermal impedance of the lower IGBT to the temperature sensor. This represents the equivalent thermal impedance of the lower tube FRD to the temperature sensor.

[0025] In this embodiment, the method for adjusting the equivalent coupling thermal impedance matrix parameters of different switching transistors to the temperature sensor based on the coolant flow signal includes: Step S201: Conduct experiments or simulations under different coolant flow conditions. By applying known loss excitations to different switching transistors, simulate the heat loss of the switching transistors in actual operation. Step S202: After applying the loss excitation, the resistance change of the temperature sensor is collected, and the influence of different switching transistors on the temperature rise of the temperature sensor is recorded by referring to the temperature-resistance relationship table. Step S203: Based on the measured temperature rise of each switching transistor to the module temperature sensor and the known loss excitation, calculate the equivalent coupling thermal impedance of different switching transistors to the module temperature sensor, and form an equivalent coupling thermal impedance matrix. The equivalent coupling thermal impedance is calculated as follows: (2) In the formula, This represents the equivalent thermal impedance of the switching transistor i to the temperature sensor. Pi represents the temperature change of the temperature sensor; Pi represents the power loss of the switching transistor i.

[0026] In this embodiment, the method for adjusting the pre-calibrated thermal impedance parameters from the chip to the coolant based on the coolant flow signal includes: Experiments or simulations were conducted under different coolant flow conditions. Known loss excitations were applied sequentially to the IGBT and FRD switching transistors to simulate the heat loss of the switching transistors during actual operation. After applying the loss excitation, the junction temperature of each switching transistor was measured and recorded. Based on the measured temperature rise of each switching transistor junction and the known loss excitation, the thermal resistance from different switching transistors to the coolant is calculated using the following formula: (3) In the above formula, This indicates the junction-water thermal resistance of the switching transistor; P represents the junction temperature change of the switching transistor; P represents the power of the switching transistor. In step S2 of this embodiment, the method for estimating the water temperature based on the module temperature sensor temperature, the total transient power loss during the switching cycles of different switching transistors, and the equivalent coupling thermal impedance matrix of different switching transistors to the module temperature sensor includes: Step S211: Obtain the actual temperature of the module sensor and calculate the total transient power loss in each switching cycle; Step S212: Determine the heating position of the switching transistor in the same phase according to the positive and negative relationship of the phase current. When the phase current is positive, the upper IGBT switching transistor and the lower FRD switching transistor are heating. When the phase current is negative, the lower IGBT switching transistor and the upper FRD switching transistor are heating. The power of the switching transistor that does not heat up is recorded as 0. Step S213, based on the equivalent coupling thermal impedance matrix The temperature rise of the module temperature sensor is calculated by linear superposition of the total transient power loss of the heating switch tube during each switching cycle according to the following formula: (4) In the above formula, This indicates the temperature rise of the module's temperature sensor. This represents the equivalent coupling thermal impedance matrix of different switching transistors to the module's temperature sensor. This indicates the power loss of the upper IGBT. This indicates the power loss of the upper tube FRD; This indicates the power loss of the lower IGBT. This indicates the power loss of the lower tube FRD; Step S214: Based on the water temperature rise and the actual temperature of the module sensor, the estimated water temperature is obtained using the following formula: (5) In the above formula, This indicates an estimate of the water temperature. Indicates the temperature of the module's temperature sensor. This indicates the temperature rise of the module's temperature sensor.

[0027] In step S2 of this embodiment, the total transient power loss during the switching cycle of different switching transistors in the same phase includes chip conduction power loss and chip switching power loss. The chip conduction power loss is calculated based on the phase current, duty cycle and module conduction voltage drop in the operating data. The chip switching power loss is calculated based on the bus voltage, phase current, switching frequency and module switching loss in the operating data.

[0028] In this embodiment, when the chip switch is an IGBT, the functional expression for the chip's conduction loss power is: (6) In the above formula, This indicates the IGBT conduction loss power. This indicates the on-state voltage drop of the module. Indicates the IGBT on-state current. Indicates the duty cycle; The functional expression for the power loss of the chip switching is: (7) In the above formula, This indicates the switching power loss of the IGBT. Indicates the IGBT switching frequency. Indicates module activation loss. Indicates module shutdown loss. Indicates bus voltage. This represents the reference voltage.

[0029] In this embodiment, when the chip switch is an FRD, the functional expression for the chip conduction loss power is: (8) In the above formula, This indicates the conduction loss power of the FRD. This indicates the on-state voltage drop of the module. Indicates the freewheeling current of the FRD. Indicates the duty cycle; The functional expression for the power loss of the chip switching is: (9) In the above formula, This indicates the power loss of the FRD switch. Indicates the FRD switching frequency. This represents the reverse recovery loss of the FRD. Indicates bus voltage. This represents the reference voltage.

[0030] In step S3 of this embodiment, the junction temperature rise of the IGBT chip is calculated based on the total transient power loss during the switching cycles of different switching transistors in the same phase and the thermal resistance from the chip to the coolant; wherein, the functional expression for the junction temperature rise of the IGBT chip is: (10) In the above formula, This indicates the junction temperature rise of the IGBT chip. This indicates the thermal resistance from the IGBT chip to the coolant. This indicates the IGBT conduction loss power. This indicates the power loss of the IGBT switching mechanism. The functional expression for the junction temperature rise of the FRD chip is: (11) In the above formula, This indicates the junction temperature rise of the FRD chip. This indicates the thermal resistance from the FRD chip to the coolant. This indicates the conduction loss power of the FRD. This indicates the power loss of the FRD switch.

[0031] In this embodiment, the estimated junction temperature of the chip is calculated using the following formula based on the chip junction temperature rise and the estimated water temperature: IGBT chip junction temperature estimation for: (12) In the above formula, This indicates an estimate of the water temperature. This indicates the junction temperature rise of the IGBT chip; FRD chip estimates junction temperature for: (13) In the above formula, This indicates the junction temperature rise of the FRD chip.

[0032] In this embodiment, the calculation of power loss is achieved by dynamically adjusting parameters through feedback of estimated junction temperature. This method can significantly improve the calculation accuracy of power loss under different operating conditions and lay an accurate foundation for subsequent temperature-related calculations.

[0033] In the water temperature estimation stage, an innovative approach was developed to construct the equivalent coupling thermal impedance matrix of different switching transistors in the same phase to the temperature sensor. By calculating the transient power loss of each switching transistor and applying the principle of linear superposition, the temperature rise of the temperature sensor is obtained. The estimated water temperature is then obtained by subtracting the actual temperature collected by the temperature sensor from the calculated temperature rise. This method is independent of specific operating conditions and only depends on which switching transistor generates heat. This not only broadens the applicable operating conditions but also significantly improves the accuracy of water temperature estimation, effectively addressing complex and variable working environments.

[0034] In obtaining the real-time estimated junction temperature of the chip, the equivalent coupling thermal impedance parameters of each switching transistor to the temperature sensor and the thermal resistance parameters from the chip to the coolant are dynamically adjusted by the flow signal fed back from the vehicle. These parameters are used to calculate the water temperature and chip junction temperature rise. Finally, by combining the estimated water temperature and chip temperature rise, the real-time estimated junction temperature of the chip is obtained. This process effectively improves the accuracy of junction temperature estimation and further ensures the stable operation and performance optimization of related equipment.

[0035] This embodiment also provides a junction temperature estimation system for a power module in a motor controller, including a microprocessor and a memory interconnected, wherein the microprocessor is programmed or configured to execute a junction temperature estimation method for a power module in a motor controller.

[0036] This embodiment also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements a method for estimating the junction temperature of the power module in a motor controller.

[0037] Those skilled in the art will understand that the above embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the functions specified in one or more boxes. The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A method for estimating the junction temperature of a power module in a motor controller, characterized in that, Includes the following steps: Step S1: Obtain the vehicle's operating condition data and power module parameters. The operating condition data includes phase current and coolant flow signals. The power module parameters include module temperature sensor temperature, module on-state voltage drop, and module switching loss. The module on-state voltage drop and module switching loss are obtained by querying a pre-stored two-dimensional relationship mapping table based on the phase current and the junction temperature feedback value estimated in the previous cycle. Step S2: Adjust the equivalent coupling thermal impedance matrix parameters of different switching transistors in the same phase to the temperature sensor and the thermal resistance parameters from the chip to the coolant based on the pre-calibrated parameters of ... Step S3: Calculate the chip junction temperature rise based on the total transient power loss during the switching cycle of different switching transistors in the same phase and the thermal resistance from the chip to the coolant. Calculate the estimated junction temperature of the chip based on the junction temperature rise and the estimated water temperature, and feed the estimated junction temperature back to step S1 for querying the module on-state voltage drop and switching loss parameters in the next cycle.

2. The method for estimating the junction temperature of the power module in the motor controller according to claim 1, characterized in that, The equivalent coupling thermal impedance matrix is: ， In the above formula, This represents the equivalent coupling thermal impedance matrix. This represents the equivalent thermal impedance of the upper IGBT to the temperature sensor. This represents the equivalent thermal impedance of the upper tube FRD to the temperature sensor. This represents the equivalent thermal impedance of the lower IGBT to the temperature sensor. This represents the equivalent thermal impedance of the lower tube FRD to the temperature sensor.

3. The method for estimating the junction temperature of the power module in the motor controller according to claim 1, characterized in that, Methods for adjusting the equivalent coupling thermal impedance matrix parameters of temperature sensors based on pre-calibrated switching transistors according to coolant flow signals include: Step S201: Conduct experiments or simulations under different coolant flow conditions. By applying known loss excitations to different switching transistors, simulate the heat loss of the switching transistors in actual operation. Step S202: After applying the loss excitation, the resistance change of the temperature sensor is collected, and the influence of different switching transistors on the temperature rise of the temperature sensor is recorded by referring to the temperature-resistance relationship table. Step S203: Based on the measured temperature rise of each switching transistor to the module temperature sensor and the known loss excitation, calculate the equivalent coupling thermal impedance of different switching transistors to the module temperature sensor, and form an equivalent coupling thermal impedance matrix. The equivalent coupling thermal impedance is calculated as follows: , In the formula, This represents the equivalent thermal impedance of the switching transistor i to the temperature sensor. Pi represents the temperature change of the temperature sensor; Pi represents the power loss of the switching transistor i.

4. The method for estimating the junction temperature of the power module in a motor controller according to claim 1, characterized in that, In step S2, the method for estimating the water temperature based on the temperature of the module temperature sensor, the total transient power loss during the switching cycles of different switches in the same phase, and the equivalent coupling thermal impedance matrix of different switches to the module temperature sensor includes: Step S211: Obtain the actual temperature of the module sensor and calculate the total transient power loss during the cycle of each switch; Step S212: Determine the heating position of the switching transistor in the same phase according to the positive and negative relationship of the phase current. When the phase current is positive, the upper IGBT switching transistor and the lower FRD switching transistor are heating. When the phase current is negative, the lower IGBT switching transistor and the upper FRD switching transistor are heating. The power of the switching transistor that does not heat up is recorded as 0. Step S213, based on the equivalent coupling thermal impedance matrix The temperature rise of the module temperature sensor is calculated by linear superposition of the total transient power loss of the heating switch tube during each switching cycle according to the following formula: ， In the above formula, Indicates the temperature rise of the module's temperature sensor. This represents the equivalent coupling thermal impedance matrix of different switching transistors to the module's temperature sensor. This indicates the power loss of the upper IGBT. This indicates the power loss of the upper tube FRD; This indicates the power loss of the lower IGBT. This indicates the power loss of the lower tube FRD; Step S214: Based on the cooling water temperature rise and the actual temperature of the module sensor, the estimated water temperature is obtained using the following formula: ， In the above formula, This indicates an estimate of the water temperature. This indicates the temperature of the module's temperature sensor. This indicates the temperature rise of the module's temperature sensor.

5. The method for estimating the junction temperature of the power module in a motor controller according to claim 1, characterized in that, In step S2, the total transient power loss during the switching cycle of different switching transistors in the same phase includes chip conduction power loss and chip switching power loss. The chip conduction power loss is calculated based on the phase current, duty cycle and module conduction voltage drop in the operating data. The chip switching power loss is calculated based on the bus voltage, phase current, switching frequency and module switching loss in the operating data.

6. The method for estimating the junction temperature of the power module in a motor controller according to claim 5, characterized in that, When the chip switching transistor is an IGBT, the functional expression for the chip's conduction loss power is: ， In the above formula, This indicates the IGBT conduction loss power. This indicates the on-state voltage drop of the module. Indicates the IGBT on-state current. Indicates the duty cycle; The functional expression for the switching power loss of the chip is: ， In the above formula, This indicates the switching power loss of the IGBT. Indicates the IGBT switching frequency. Indicates module activation loss. Indicates module shutdown loss. Indicates bus voltage. This represents the reference voltage.

7. The method for estimating the junction temperature of the power module in a motor controller according to claim 5, characterized in that, When the chip switch is an FRD, the functional expression for the chip's conduction loss power is: ， In the above formula, This indicates the conduction loss power of the FRD. This indicates the on-state voltage drop of the module. Indicates the freewheeling current of the FRD. Indicates the duty cycle; The functional expression for the switching power loss of the chip is: , In the above formula, This indicates the power loss of the FRD switch. Indicates the FRD switching frequency. This represents the reverse recovery loss of the FRD. Indicates bus voltage. This represents the reference voltage.

8. The method for estimating the junction temperature of the power module in a motor controller according to claim 1, characterized in that, In step S3, the junction temperature rise of the IGBT chip is calculated based on the total transient power loss during the switching cycles of different switching transistors in the same phase and the thermal resistance from the chip to the coolant; wherein, the functional expression for the junction temperature rise of the IGBT chip is: ， In the above formula, This indicates the junction temperature rise of the IGBT chip. This indicates the thermal resistance from the IGBT chip to the coolant. This indicates the IGBT conduction loss power. This indicates the power loss of the IGBT switching mechanism. The functional expression for the junction temperature rise of the FRD chip is: ， In the above formula, This indicates the junction temperature rise of the FRD chip. This indicates the thermal resistance from the FRD chip to the coolant. This indicates the conduction loss power of the FRD. This indicates the power loss of the FRD switch.

9. The method for estimating the junction temperature of the power module in a motor controller according to claim 8, characterized in that, The estimated junction temperature of the chip is calculated using the following formula based on the chip junction temperature rise and the estimated water temperature: IGBT chip junction temperature estimation for: , In the above formula, This indicates an estimate of the water temperature. This indicates the junction temperature rise of the IGBT chip; FRD chip estimates junction temperature for: ， In the above formula, This indicates the junction temperature rise of the FRD chip.

10. A junction temperature estimation system for a power module in a motor controller, comprising a microprocessor and a memory interconnected, characterized in that, The microprocessor is programmed or configured to execute the junction temperature estimation method for the power module in the motor controller according to any one of claims 1 to 9.

Images