IGBT junction temperature estimation method and system for motor controller

Abstract

The invention provides an IGBT junction temperature estimation method and system for a motor controller. The method comprises the steps that S1, working condition data and power module parameters of a whole vehicle are acquired; s2, calculating the average loss power of each switch tube based on real-time working conditions and module parameters, determining equivalent coupling thermal impedance matrix parameters of different switch tubes to a temperature sensor and thermal resistance parameters from a chip to cooling liquid according to a cooling liquid flow signal, and obtaining a power compensation coefficient in combination with the rotating speed of a motor, the temperature rise of the temperature sensor is calculated according to the linear superposition principle through the loss power, the compensation coefficient and the equivalent coupling thermal impedance matrix of the different switch tubes, and then the estimated water temperature is obtained, and S3, the chip junction temperature is obtained according to the loss power, the power compensation coefficient, the thermal resistance from the chip to the cooling liquid and the estimated water temperature of the different switch tubes in the same phase. According to the method, the resource occupation of the processor is effectively reduced, and the water temperature and junction temperature estimation precision under all working conditions such as locked-rotor and low-rotating-speed conditions is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor controllers for new energy vehicles, and in particular to an IGBT junction temperature estimation method and system for a motor controller. BACKGROUND

[0002] With the rapid development of new energy vehicle technology, the motor controller, as the core component of the power system, its operation reliability is directly related to the safety and performance of the vehicle. Among them, the IGBT power module is the key element of current transformation, and the accurate estimation of its junction temperature is of great significance to realize the overheat protection, improve the power output capability and prolong the service life of the device. However, in practical application, especially in complex conditions such as locked-rotor and low-speed, due to the highly nonlinear operation state of the motor, the traditional junction temperature estimation method faces severe challenges. The existing technology generally relies on the average loss model to calculate the power loss through the phase current amplitude, the regulation system and the power factor, and combines a fixed or simplified thermal resistance network to calculate the junction temperature. For example, the Chinese patent application with publication number CN112765786A discloses a junction temperature estimation method based on average loss and temperature sensor feedback, but this method causes the equivalent thermal resistance parameters to mismatch due to the change of the heating chip position with the angle in the locked-rotor condition, and cannot reflect the instantaneous fluctuations of the junction temperature at low speed, so the scope of application is limited. At the same time, the heating position of different switching tubes in the power module will change under different working conditions, while the layout position of the temperature sensor is fixed, which causes the temperature rise sensed by the temperature sensor to be significantly affected by the heat path. The existing technology mostly does not model the equivalent coupling thermal resistance between different heat sources and sensors, and also fails to fully consider the dynamic influence of factors such as cooling liquid flow and motor speed on the thermal resistance characteristics, further reducing the accuracy of the water temperature and junction temperature estimation. Although the Chinese patent application with publication number CN119720501A proposes to compensate the thermal resistance parameters through the cooling liquid flow to improve the estimation accuracy, this scheme still does not consider the problem of the change of the heating chip position caused by different locked-rotor angles, and is limited by the layout of the module temperature sensor, so the estimation result still has deviations. SUMMARY

[0003] The technical problem to be solved by the present application is that, in view of the technical problems existing in the prior art, the present application provides an IGBT junction temperature estimation method and system for a motor controller, which aims to solve the problem of junction temperature estimation deviation caused by the change of the heating position, the nonlinearity of the thermal resistance and the response lag of the temperature sensor under low-speed and locked-rotor conditions.

[0004] To solve the above technical problems, the technical solution provided by the present application is as follows: An IGBT junction temperature estimation method for a motor controller, comprising the following method: Step S1, obtaining the working condition data of the whole vehicle and the power module parameters, the working condition data including bus voltage, phase current, switching frequency, modulation coefficient, power factor, motor speed and cooling liquid flow signal, the power module parameters including temperature sensor temperature, module conduction voltage drop curve and module switching loss curve; Step S2, calculating the average loss power of different switching tubes in the same phase according to the working condition data and the power module parameters respectively; According to the cooling liquid flow signal, adjusting the equivalent coupling thermal impedance matrix parameters of different switching tubes in the same phase to the power module temperature sensor and the thermal impedance parameters from the chip to the cooling liquid based on the pre-calibration, so as to obtain the equivalent coupling thermal impedance matrix parameters of different switching tubes to the power module temperature sensor and the thermal impedance parameters from the chip to the cooling liquid under the cooling liquid flow signal; According to the motor speed, the power compensation coefficient of different switching tubes is obtained by querying the pre-stored two-dimensional relationship mapping table; According to the loss power of different switching tubes in the same phase, the power compensation coefficient, the equivalent coupling thermal impedance matrix of different switching tubes in the same phase to the power module temperature sensor, the temperature rise of the temperature sensor is calculated by linear superposition principle, and the estimated water temperature is obtained by the difference between the actual power module temperature sensor temperature and the temperature sensor temperature rise; Step S3, calculating the chip junction temperature according to the loss power of different switching tubes in the same phase, the power compensation coefficient, the thermal impedance parameters from the chip to the cooling liquid and the estimated water temperature.

[0005] Optionally, in step S2, the average loss power of different switching tubes in the same phase is calculated according to the working condition data and the power module parameters respectively, including: According to the phase current, the modulation coefficient, the power factor, the module conduction voltage drop curve, the average conduction loss power of the chip is calculated; According to the bus voltage, the phase current, the switching frequency, the module switching loss curve, the average switching loss power of the chip is calculated.

[0006] Optionally, the average conduction loss power of the chip includes IGBT average conduction loss power and FRD average conduction loss power; The calculation formula of the IGBT average conduction loss power is:

[0007] Wherein, P cond,G IGBT average conduction loss power, The intercept of the module conduction voltage drop curve represents the threshold voltage, r(T vj ) The slope of the module conduction voltage drop curve represents the conduction slope resistance,i C denotes the phase current amplitude, m denotes the modulation coefficient, cosφ denotes the power factor; The calculation formula of the FRD average conduction loss power is:

[0008] wherein, P cond,D denotes the FRD conduction loss power, U T0 (Tvj) The intercept of the module conduction voltage drop curve corresponds to the threshold voltage, r T (T vj ) The slope of the module conduction voltage drop curve corresponds to the on-state slope resistance, i F denotes the phase current amplitude, m denotes the modulation coefficient, cosφ denotes the power factor.

[0009] Optionally, the chip average switching loss power includes IGBT average switching loss power and FRD average switching loss power; The IGBT average switching loss power includes IGBT on-process loss power and IGBT off-process loss power; the calculation formula of the IGBT on-process loss power is:

[0010] wherein, P on，G denotes the IGBT on-process loss power, f sw denotes the switching frequency, E on (I nom ,U nom ，T vj) denotes the on-process loss, i C denotes the phase current amplitude, I nom denotes the reference current, i C denotes the real-time phase current amplitude, U dc denotes the real-time bus voltage, U nom denotes the reference bus voltage; The calculation formula of the IGBT turn-off process loss power is:

[0011] Wherein, P off，G IGBT turn-off process loss power, f sw Switching frequency, E off (I nom ,U nom ，T vj) Turn-off process loss, i C Phase current amplitude, I nom Reference current, i C Real-time phase current amplitude, U dc Real-time bus voltage, U nom Reference bus voltage; The calculation formula of the FRD switching loss power is:

[0012] Wherein, P sw，D FRD reverse recovery process loss power, f sw Switching frequency, E rec (I nom ,U nom ，T vj) Reverse recovery process loss, I nom Reference current, i F Real-time phase current amplitude, U dc Real-time bus voltage, U nom Reference bus voltage.

[0013] Optionally, in step S2, the method for adjusting the equivalent coupling thermal impedance matrix parameters of the power module temperature sensor by the cooling liquid flow signal is: The experiment or simulation is carried out under different cooling liquid flow conditions, and the known loss excitation is applied on different switch tubes in the same phase to simulate the heat loss of the switch tube in actual work; The influence of the heat generation of different switch tubes on the temperature sensor temperature rise is recorded by collecting the resistance change of the temperature sensor and comparing the temperature and resistance value table; According to the temperature change of the temperature sensor and the average loss power of the switch tube, the equivalent coupling thermal impedance of different switch tubes to the power module temperature sensor is calculated by the following formula: , Among them, The equivalent coupling thermal impedance of the switch tube to the temperature sensor, The temperature change of the temperature sensor is represented by ΔT; The total loss power of the switch tube .

[0014] Optionally, according to the equivalent coupling thermal impedance of different switch tubes to the power module temperature sensor, the equivalent coupling thermal impedance matrix between different switch tubes and the module temperature sensor is obtained , and the equivalent coupling thermal impedance matrix is: , Among them, The equivalent coupling thermal impedance matrix is represented by Rth; Z t_G The equivalent coupling thermal impedance of the upper tube IGBT to the temperature sensor is represented by Rth1; Z t_D The equivalent coupling thermal impedance of the upper tube FRD to the temperature sensor is represented by Rth2; Z d_G The equivalent coupling thermal impedance of the lower tube IGBT to the temperature sensor is represented by Rth3; Z d_D The equivalent coupling thermal impedance of the lower tube FRD to the temperature sensor is represented by Rth4.

[0015] Optionally, according to the positive and negative of the phase current, the different heat generation positions of different switch tubes in the same phase are determined, including: when the phase current is positive, the upper tube IGBT and the lower tube FRD generate heat; when the phase current is negative, the lower tube IGBT and the upper tube FRD generate heat; the switch tube not generating heat is recorded as 0.

[0016] Optionally, the temperature sensor temperature rise calculation formula in step S2 is: , Among them, The temperature sensor temperature rise is represented by ΔT; The power compensation coefficient under the corresponding speed condition is represented by K. represents the equivalent coupling thermal impedance matrix of different switching tubes to the module temperature sensor, represents the upper tube IGBT loss power; represents the upper tube FRD loss power; represents the lower tube IGBT loss power; represents the lower tube FRD loss power.

[0017] Optionally, step S3 comprises: IGBT chip junction temperature rise is calculated according to the loss power of different switching tubes in the same phase, the power compensation coefficient and the thermal impedance parameter of IGBT chip to cooling liquid by using the following formula, and IGBT chip estimated junction temperature is obtained according to the estimated water temperature and the IGBT chip junction temperature rise: , , wherein, represents the IGBT chip junction temperature rise, represents the power compensation coefficient, represents the thermal impedance parameter of IGBT chip to cooling liquid, P cond,G represents the IGBT average conduction loss power, P on，G represents the IGBT on-process loss power, P off，G represents the IGBT off-process loss power, represents the IGBT chip estimated junction temperature, T w represents the estimated water temperature; FRD chip junction temperature rise is calculated according to the loss power of different switching tubes in the same phase, the power compensation coefficient and the thermal impedance parameter of FRD chip to cooling liquid by using the following formula, and FRD chip estimated junction temperature is obtained according to the estimated water temperature and the FRD chip junction temperature rise: , , wherein, represents the FRD chip junction temperature rise, represents the power compensation coefficient, represents the thermal impedance parameter of FRD chip to cooling liquid, P cond,D represents the FRD conduction loss power, P sw，D represents the FRD reverse recovery process loss power, represents the FRD chip estimated junction temperature.

[0018] The application also provides an IGBT junction temperature estimation system for a motor controller, comprising a microprocessor and a memory connected to each other, the microprocessor being programmed or configured to execute the IGBT junction temperature estimation method for the motor controller.

[0019] Compared with the prior art, the application has the beneficial effects that: The application calculates the average loss power of different switching tubes in the same phase through working condition data and power module parameters, significantly reduces the occupation of the processor computing resources under the premise of ensuring the estimation function, and improves the overall operation efficiency of the system; the application introduces a real-time compensation mechanism based on the motor speed and a dynamic thermal impedance adjustment strategy, effectively expands the applicable boundary of the algorithm and improves the estimation accuracy in the whole working condition range; in addition, the application establishes a refined equivalent coupled thermal impedance matrix, realizes independent quantitative characterization of the thermal influence of different switching tubes in the same phase, and improves the reliability and accuracy of the backstepping water temperature and junction temperature from the temperature sensor. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The application also provides an IGBT junction temperature estimation method for a motor controller. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.

[0022] As shown in the drawings, Figure 1 The application provides an IGBT junction temperature estimation method for a motor controller, comprising the following methods: Step S1, obtaining working condition data and power module parameters of the whole vehicle, the working condition data comprising bus voltage, phase current, switching frequency, modulation coefficient, power factor, motor speed and cooling liquid flow signal, and the power module parameters comprising temperature sensor temperature, module on-voltage drop curve and module switching loss curve; Step S2, calculating the average loss power of different switching tubes in the same phase according to the working condition data and the power module parameters; According to the cooling liquid flow signal, adjusting the equivalent coupled thermal impedance matrix parameters of different switching tubes in the same phase to the power module temperature sensor and the thermal resistance parameters from the chip to the cooling liquid based on the pre-design, so as to obtain the equivalent coupled thermal impedance matrix parameters of different switching tubes to the power module temperature sensor and the thermal resistance parameters from the chip to the cooling liquid under the cooling liquid flow signal; According to the motor speed, a two-dimensional relationship mapping table is queried to obtain the power compensation coefficients of different switching tubes in the phase; According to the loss power of different switching tubes in the phase, the power compensation coefficients, and the equivalent coupling thermal impedance matrix of different switching tubes in the phase to the power module temperature sensor, the temperature rise of the temperature sensor is calculated through the linear superposition principle, and the estimated water temperature is obtained through the difference between the actual power module temperature sensor temperature and the temperature sensor temperature rise; Step S3, according to the loss power of different switching tubes in the phase, the power compensation coefficients, the thermal resistance parameters from the chip to the cooling liquid, and the estimated water temperature, the chip junction temperature is calculated.

[0023] In this embodiment, the estimation of water temperature and junction temperature is realized by calculating the average power of the switching tube. Compared with the calculation method based on instantaneous power, although the calculation period of the average power algorithm is increased, it significantly reduces the occupation of the processor computing resources, improves the system running efficiency, and is especially suitable for embedded application scenarios with limited resources and low real-time requirements.

[0024] In step S2 of this embodiment, the average loss power of different switching tubes in the phase is calculated according to the working condition data and the power module parameters, including: According to the phase current, the modulation coefficient, the power factor, and the module conduction voltage drop curve, the chip average conduction loss power is calculated; According to the bus voltage, the phase current, the switching frequency, and the module switching loss curve, the chip average switching loss power is calculated.

[0025] In this embodiment, the chip average conduction loss power includes IGBT average conduction loss power and FRD average conduction loss power; The calculation formula of IGBT average conduction loss power is: (1) Among them, P cond,G IGBT average conduction loss power is represented by IGBT average conduction loss power, The intercept corresponding to the module conduction voltage drop curve represents the threshold voltage, r(T vj ) The slope corresponding to the module conduction voltage drop curve represents the conduction slope resistance, i C The phase current amplitude is represented by I, m The modulation coefficient is represented by m, cosφ The power factor is represented by pf, U CE = U CE0 (Tvj) + r(T vj ) i C , U CE denotes the on-voltage drop of the IGBT.

[0026] The calculation formula of the average on-loss power of the FRD is: (2) wherein, P cond,D denotes the on-loss power of the FRD, U T0 (Tvj) The intercept of the on-voltage drop curve of the corresponding module denotes the threshold voltage, r T (T vj ) The slope of the on-voltage drop curve of the corresponding module denotes the on-state slope resistance, i F denotes the phase current amplitude, m denotes the modulation coefficient, cosφ denotes the power factor, U CE = U T0 (Tvj) + r T (T vj ) i F , U CE denotes the on-voltage drop of the FRD.

[0027] In the embodiment, the average switching loss power of the chip includes the average switching loss power of the IGBT and the average switching loss power of the FRD; The average switching loss power of the IGBT includes the on-process loss power of the IGBT and the off-process loss power of the IGBT; the calculation formula of the on-process loss power of the IGBT is: (3) wherein, P on，G denotes the on-process loss power of the IGBT, f sw denotes the switching frequency, E on (I nom ,U nom ，T vj)represents the switching loss, i C represents the phase current amplitude, I nom represents the reference current, i C represents the real-time phase current amplitude, U dc represents the real-time bus voltage, U nom represents the reference bus voltage; The calculation formula of the IGBT turn-off process loss power is: (4) wherein, P off，G represents the IGBT turn-off process loss power, f sw represents the switching frequency, E off (I nom ,U nom ，T vj) represents the turn-off process loss, i C represents the phase current amplitude, I nom represents the reference current, i C represents the real-time phase current amplitude, U dc represents the real-time bus voltage, U nom represents the reference bus voltage; The calculation formula of the FRD switching loss power is: (5) wherein, P sw，D represents the FRD reverse recovery process loss power, f sw represents the switching frequency, E rec (I nom ,U nom ，T vj) represents the reverse recovery process loss, I nom represents the reference current, i F represents the real-time phase current amplitude, U dc represents the real-time bus voltage, Unom This indicates the reference bus voltage.

[0028] In this embodiment, the method for adjusting the equivalent coupling thermal impedance matrix parameters of different switching transistors to the power module temperature sensor based on the coolant flow signal is as follows: Experiments or simulations were conducted under different coolant flow conditions. Known loss excitations were applied to different switching transistors in the same phase to simulate the heat loss of the switching transistors during actual operation. By collecting the resistance change of the temperature sensor, the influence of different switching transistors on the temperature rise of the temperature sensor is recorded by referring to the temperature-resistance relationship table. Based on the temperature change of the temperature sensor and the average power loss of the switching transistor, the equivalent coupling thermal impedance of different switching transistors to the temperature sensor of the power module is calculated using the following formula: (6) in, Indicates the switching transistor The equivalent coupling thermal impedance of the temperature sensor, This indicates the amount of temperature change from the temperature sensor. Indicates the switching transistor Total power loss.

[0029] In specific application embodiments, the calibration of the equivalent coupling thermal impedance matrix parameters is usually performed under test or simulation conditions. A fixed current is applied to a single switch or a constant total power loss is applied directly as an excitation source, and the thermal impedance value is calculated by measuring the temperature rise response.

[0030] In this embodiment, the equivalent thermal resistance matrix parameters from the chip to the coolant can be obtained through testing or simulation under different flow conditions. Known loss excitations are 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 excitations, the junction temperature of each switching transistor is measured and recorded. Based on the measured temperature rise of each switching transistor's junction and the known loss excitations, the junction-to-water thermal resistance of different switching transistors is calculated using the following formula: (7) In the formula, This indicates the junction-water thermal resistance of the switching transistor; This represents the change in junction temperature of the switching transistor; P represents the power loss applied to the switching transistor.

[0031] In this embodiment, the equivalent coupling thermal impedance matrix between different switching transistors and the power module temperature sensor is obtained based on the equivalent coupling thermal impedance of different switching transistors to the power module temperature sensor. The equivalent coupling thermal impedance matrix is: (8) wherein, represents the equivalent coupling thermal impedance matrix of the upper IGBT and the upper FRD to the temperature sensor, Z t_G represents the equivalent coupling thermal impedance of the upper IGBT to the temperature sensor; Z t_D represents the equivalent coupling thermal impedance of the upper FRD to the temperature sensor; Z d_G represents the equivalent coupling thermal impedance of the lower IGBT to the temperature sensor; Z d_D represents the equivalent coupling thermal impedance of the lower FRD to the temperature sensor.

[0032] In the embodiment, the determination of the different heating positions of the different switching tubes in the same phase according to the positive and negative situations of the phase current comprises: when the phase current is positive, the upper IGBT and the lower FRD heat; when the phase current is negative, the lower IGBT and the upper FRD heat; the power of the switching tube that does not heat is recorded as 0.

[0033] In step S2 of the embodiment, the temperature rise calculation formula of the temperature sensor is: (9) wherein, represents the temperature rise of the temperature sensor, represents the power compensation coefficient under the corresponding rotating speed condition, represents the equivalent coupling thermal impedance matrix of the different switching tubes to the module temperature sensor, represents the loss power of the upper IGBT; represents the loss power of the upper FRD; represents the loss power of the lower IGBT; represents the loss power of the lower FRD.

[0034] In the embodiment, the water temperature is estimated according to the real-time temperature sensor temperature and the temperature rise of the temperature sensor, and the formula is as follows: (10) wherein, T w represents the estimated water temperature, T ntc represents the temperature sensor temperature, ΔTntc represents the temperature rise of the temperature sensor.

[0035] In step S3 of the embodiment, the following is included: The IGBT chip junction temperature rise is calculated according to the loss power of the different switching tubes in the same phase, the power compensation coefficient, and the thermal impedance parameter from the IGBT chip to the cooling liquid by using the following formula, and the IGBT chip estimated junction temperature is obtained according to the estimated water temperature and the IGBT chip junction temperature rise. (11) (12) wherein, represents IGBT chip junction temperature rise, represents power compensation coefficient, represents IGBT chip to cooling liquid thermal resistance parameter, P cond,G represents IGBT average conduction loss power, P on，G represents IGBT turn-on process loss power, P off，G represents IGBT turn-off process loss power, represents IGBT chip estimated junction temperature, T w represents estimated water temperature; IGBT chip junction temperature rise is calculated according to loss power of different switching tubes in the same phase, power compensation coefficient, and FRD chip to cooling liquid thermal resistance parameter, and FRD chip estimated junction temperature is obtained according to estimated water temperature and IGBT chip junction temperature rise: (13) (14) wherein, represents FRD chip junction temperature rise, represents power compensation coefficient, represents FRD chip to cooling liquid thermal resistance parameter, P cond,D represents FRD conduction loss power, P sw，D represents FRD reverse recovery process loss power, represents FRD chip estimated junction temperature.

[0036] The application also provides an IGBT junction temperature estimation system for motor controller, which comprises a microprocessor and a memory connected with each other, and the microprocessor is programmed or configured to execute the IGBT junction temperature estimation method for motor controller.

[0037] The above is only the preferred embodiment of the application, and does not limit the application in any form. Although the application has been disclosed as above with the preferred embodiment, it is not intended to limit the application. Therefore, any simple modification, equivalent change and modification of the above embodiment without departing from the technical solution of the application, and according to the technical essence of the application, should fall within the protection scope of the technical solution of the application.

Claims

1. A method for estimating the junction temperature of an IGBT used 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 bus voltage, phase current, switching frequency, modulation coefficient, power factor, motor speed, and coolant flow signal. The power module parameters include temperature sensor temperature, module conduction voltage drop curve, and module switching loss curve. Step S2: Calculate the average power loss of different switching transistors in the same phase based on the operating condition data and power module parameters; Based on the coolant flow signal, the equivalent coupling thermal impedance matrix parameters of different switching transistors in the same phase to the power module temperature sensor and the thermal resistance parameters from the chip to the coolant are adjusted respectively, thereby obtaining the equivalent coupling thermal impedance matrix parameters of different switching transistors to the power module temperature sensor and the thermal resistance parameters from the chip to the coolant under the coolant flow signal. Based on the motor speed, the power compensation coefficients of different switching transistors are obtained by querying a pre-stored two-dimensional relationship mapping table; Based on the power loss, power compensation coefficient, and equivalent coupling thermal impedance matrix of different switching transistors in the same phase to the power module temperature sensor, the temperature rise of the temperature sensor is calculated by the principle of linear superposition, and the water temperature is estimated by the difference between the actual power module temperature sensor temperature and the temperature rise of the temperature sensor. Step S3: Calculate the chip junction temperature based on the power loss, power compensation coefficient, thermal resistance parameters from the chip to the coolant, and estimated water temperature of the different switching transistors in the same phase.

2. The IGBT junction temperature estimation method for motor controllers according to claim 1, characterized in that, In step S2, calculating the average power loss of different switching transistors in the same phase based on the operating condition data and power module parameters includes: The average conduction loss power of the chip is calculated based on the phase current, modulation coefficient, power factor, and module on-state voltage drop curve. The average switching power loss of the chip is calculated based on the bus voltage, phase current, switching frequency, and module switching loss curve.

3. The IGBT junction temperature estimation method for motor controllers according to claim 2, characterized in that, The average conduction loss power of the chip includes the average conduction loss power of the IGBT and the average conduction loss power of the FRD. The formula for calculating the average conduction loss power of the IGBT is as follows: in, P cond,G This represents the average on-state power loss of the IGBT. The intercept of the corresponding module's on-state voltage drop curve represents the threshold voltage. r(T vj ) The slope of the corresponding module's on-state voltage drop curve represents the on-state slope resistance. i C Indicates the phase current amplitude. m Represents the modulation coefficient. cosφ Indicates the power factor; The formula for calculating the average conduction loss power of the FRD is as follows: in, P cond,D This indicates the conduction loss power of the FRD. U T0 (Tvj) The intercept of the corresponding module's on-state voltage drop curve represents the threshold voltage. r T (T vj ) The slope of the corresponding module's on-state voltage drop curve represents the on-state slope resistance. i F Indicates the phase current amplitude. m Represents the modulation coefficient. cosφ This represents the power factor.

4. The IGBT junction temperature estimation method for motor controllers according to claim 2, characterized in that, The average switching power loss of the chip includes the average switching power loss of the IGBT and the average switching power loss of the FRD. The average switching power loss of the IGBT includes the power loss during the IGBT turn-on process and the power loss during the IGBT turn-off process; the formula for calculating the power loss during the IGBT turn-on process is: in, P on，G This indicates the power loss during the IGBT turn-on process. f sw Indicates the switching frequency. E on (I nom ,U nom ，T vj) This indicates the loss during the opening process. i C Indicates the phase current amplitude. I nom Indicates the reference current. i C Indicates the real-time phase current amplitude. U dc This indicates the real-time bus voltage. U nom Indicates the reference bus voltage; The formula for calculating the power loss during the IGBT turn-off process is as follows: in, P off，G This indicates the power loss during the IGBT turn-off process. f sw Indicates the switching frequency. E off (I nom ,U nom ，T vj) This indicates the loss during the shutdown process. i C Indicates the phase current amplitude. I nom Indicates the reference current. i C Indicates the real-time phase current amplitude. U dc This indicates the real-time bus voltage. U nom Indicates the reference bus voltage; The formula for calculating the power loss of the FRD switch is as follows: in, P sw，D This indicates the power loss during the FRD reverse recovery process. f sw Indicates the switching frequency. E rec (I nom ,U nom ，T vj) This indicates the loss during the reverse recovery process. I nom Indicates the reference current. i F Indicates the real-time phase current amplitude. U dc This indicates the real-time bus voltage. U nom This indicates the reference bus voltage.

5. The IGBT junction temperature estimation method for motor controllers according to claim 1, characterized in that, In step S2, the method for adjusting the equivalent coupling thermal impedance matrix parameters of different switching transistors to the power module temperature sensor based on the coolant flow signal is as follows: Experiments or simulations were conducted under different coolant flow conditions. Known loss excitations were applied to different switching transistors in the same phase to simulate the heat loss of the switching transistors during actual operation. By collecting the resistance change of the temperature sensor, the influence of different switching transistors on the temperature rise of the temperature sensor is recorded by referring to the temperature-resistance relationship table. Based on the temperature change of the temperature sensor and the average power loss of the switching transistor, the equivalent coupling thermal impedance of different switching transistors to the temperature sensor of the power module is calculated using the following formula: ， in, Indicates the switching transistor The equivalent coupling thermal impedance of the temperature sensor, This indicates the amount of temperature change from the temperature sensor. Indicates the switching transistor Total power loss.

6. The IGBT junction temperature estimation method for a motor controller according to claim 5, characterized in that, Based on the equivalent coupling thermal impedance of different switching transistors to the power module temperature sensor, the equivalent coupling thermal impedance matrix between different switching transistors and the module temperature sensor is obtained. The equivalent coupling thermal impedance matrix is: ， in, This represents the equivalent coupling thermal impedance matrix. Z t_G This represents the equivalent thermal impedance of the upper IGBT to the temperature sensor. Z t_D This represents the equivalent thermal impedance of the upper tube FRD to the temperature sensor. Z d_G This represents the equivalent thermal impedance of the lower IGBT to the temperature sensor. Z d_D This represents the equivalent thermal impedance of the lower tube FRD to the temperature sensor.

7. The IGBT junction temperature estimation method for a motor controller according to claim 5, characterized in that, Determining the different heating locations of different switching transistors in the same phase based on the sign of the phase current includes: when the phase current is positive, the upper IGBT and the lower FRD are heating up; when the phase current is negative, the lower IGBT and the upper FRD are heating up; the power of a switching transistor that does not heat up is recorded as 0.

8. The IGBT junction temperature estimation method for a motor controller according to claim 1, characterized in that, The temperature rise calculation formula for the temperature sensor mentioned in step S2 is as follows: ， in, Indicates the temperature rise of the temperature sensor. This represents the power compensation coefficient under the corresponding speed condition. 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.

9. The IGBT junction temperature estimation method for a motor controller according to claim 1, characterized in that, Step S3 includes: The junction temperature rise of the IGBT chip is calculated using the following formula based on the power loss, power compensation coefficient, and thermal resistance parameters from the IGBT chip to the coolant for different switching transistors in the same phase. The estimated junction temperature of the IGBT chip is then obtained based on the estimated water temperature and the junction temperature rise of the IGBT chip: ， ， in, This indicates the junction temperature rise of the IGBT chip. Indicates the power compensation coefficient. This represents the thermal resistance parameter from the IGBT chip to the coolant. P cond,G This represents the average on-state power loss of the IGBT. P on，G This indicates the power loss during the IGBT turn-on process. P off，G This indicates the power loss during the IGBT turn-off process. This indicates the estimated junction temperature of the IGBT chip. T w This indicates an estimated water temperature; The junction temperature rise of the FRD chip is calculated using the following formula based on the power loss, power compensation coefficient, and thermal resistance parameters from the FRD chip to the coolant for different switching transistors in the same phase. The estimated junction temperature of the FRD chip is then obtained based on the estimated water temperature and the junction temperature rise. ， ， in, This indicates the junction temperature rise of the FRD chip. Indicates the power compensation coefficient. This indicates the thermal resistance parameter from the FRD chip to the coolant. P cond,D This indicates the conduction loss power of the FRD. P sw，D This indicates the power loss during the FRD reverse recovery process. This indicates the estimated junction temperature of the FRD chip.

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

Images