An over-temperature protection method, computer device, readable storage medium and motor vehicle

Abstract

The application discloses a kind of over-temperature protection method, computer equipment, readable storage medium and motor vehicle, it is related to automobile technical field, motor controller is prevented power module junction temperature excessively high by the over-temperature protection method to its power module and carries out over-temperature protection, including the following steps: obtaining current coolant flow, according to it judges current water pump gear, according to three electric operating parameter calculates the junction temperature of power module corresponding to each demarcation value of coolant flow, according to the junction temperature of power module corresponding to the demarcation value of coolant flow, water pump gear and demarcation value, calculate current power module junction temperature, according to motor speed and current power module junction temperature obtains junction temperature torque limit value, and adjusts water pump gear and IGBT switching frequency.The over-temperature protection method provided by the application improves junction temperature estimation accuracy, while effectively reducing junction temperature.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, specifically to an over-temperature protection method, a computer device, a readable storage medium, and a motor vehicle. Background Technology

[0002] With the implementation of national strategies, emission regulations for motor vehicles are becoming increasingly stringent. Coupled with government support for new energy vehicles, more and more automakers are launching hybrid, plug-in hybrid, range-extended, and pure electric vehicles. These vehicles are all equipped with an electric motor, a battery pack to power the motor, and a motor controller to control the motor.

[0003] As the control unit of the electric drive assembly, the motor controller plays a crucial role in safety and stability. The motor controller contains a large number of IGBTs and diodes, which generate significant heat during operation. Therefore, proper heat dissipation for the motor controller is vital for the safety and stability of the entire vehicle. Insufficient heat dissipation leading to heat buildup can cause IGBTs and diodes to burn out or even fail. Thus, for vehicles equipped with both motors and motor controllers, controlling the junction temperature and preventing overheating is of paramount importance. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an over-temperature protection method that improves the accuracy of junction temperature estimation while effectively reducing the junction temperature.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An over-temperature protection method is provided, in which a motor controller performs over-temperature protection on its power module to prevent the junction temperature of the power module from becoming too high. The over-temperature protection method includes the following steps:

[0007] Flow rate classification: Obtain the current coolant flow rate and determine the current water pump speed based on the current coolant flow rate and the coolant flow rate threshold value. The water pump speed is classified by the threshold value.

[0008] Junction temperature calculation based on boundary values: The junction temperature of the power module corresponding to each boundary value of the coolant flow is calculated based on the three operating parameters, including the switching frequency of the insulated gate bipolar transistor.

[0009] Insulated Gate Bipolar Transistor, or IGBT. For ease of description, IGBT will be used to refer to Insulated Gate Bipolar Transistor from now on.

[0010] Junction temperature calculation: Calculate the junction temperature of the power module corresponding to the current coolant flow rate based on the current coolant flow rate, the coolant flow rate threshold corresponding to the current pump speed, and the junction temperature of the power module corresponding to the threshold value.

[0011] Adjustment: Obtain the junction temperature torque limit based on the power module junction temperature corresponding to the motor speed and the current coolant flow rate, and adjust the water pump speed and IGBT switching frequency.

[0012] The technical solution provided by this invention enables dynamic estimation of the junction temperature of the power module, providing more effective protection against excessively high junction temperatures, improving the limitation of junction temperature torque, and fully utilizing the current capability of the hardware. After limiting the junction temperature torque, the switching frequency of the IGBT is actively adjusted and the vehicle water pump speed is increased to reduce the junction temperature, avoid junction temperature torque limitation, and further enhance hardware safety.

[0013] Optionally, the junction temperature of the power module corresponding to the current coolant flow rate can be calculated using the following formula:

[0014] Tj = Tj n +(Tj n+1 -Tj n ) / (L n+1 -L n )*(LL n )

[0015] Where Tj is the junction temperature of the power module corresponding to the current coolant flow rate, and n is the current water pump speed and the corresponding speed boundary value number. n L is the junction temperature of the power module corresponding to the cutoff value of the coolant flow rate, L is the current coolant flow rate, and Ln is the cutoff value of the coolant flow rate.

[0016] In this invention, the junction temperature of the power module is calculated by interpolation, which improves the accuracy of the junction temperature calculation and avoids the situation where the estimated junction temperature is lower than the actual junction temperature at low flow rates, thus protecting the module safety.

[0017] Optionally, calculating the power module junction temperature corresponding to each threshold value of the coolant flow rate includes the following steps:

[0018] Calculate the junction temperature of the IGBT chip and the junction temperature of the diode chip for each bridge arm, and take the larger of the two values ​​as the junction temperature of the bridge arm.

[0019] The maximum junction temperature among all bridge arms is taken as the power module junction temperature.

[0020] Optionally, calculating the junction temperature of the IGBT chip includes the following steps:

[0021] The conduction loss of the IGBT chip can be calculated using the following formula:

[0022]

[0023] Among them, P cond,IGBT V represents the conduction loss of the IGBT chip, t is time, T0 is the chip's duty cycle, τ(t) is the duty cycle of the IGBT chip, and V ce (t) represents the voltage between the collector and emitter of the IGBT, V ce0 For IGBT output characteristic curve I c =f(V ce Extend the tangent to the linear segment in the middle to intersect V. ce The value at the intersection point, r ce For IGBT output characteristic curve I c =f(V ce The slope of the tangent line to the linear segment in the equation, I m ω is the current amplitude, ω is the angular velocity, and m is the modulation ratio. The phase angle;

[0024] The switching losses of the IGBT chip can be calculated using the following formula:

[0025]

[0026] Among them, P SW,IGBT f represents the switching loss of the IGBT chip. sw E is the switching frequency. on (I nom V nom E represents the typical start-up loss under operating conditions. off (I nom V nom V represents the typical turn-off loss under operating conditions. dc Battery voltage;

[0027] The junction temperature of the IGBT chip can be calculated using the following formula:

[0028]

[0029] Among them, Tj IGBT P is the junction temperature of the IGBT chip. IGBT R represents the total loss of the IGBT chip. th,IGBT T represents the thermal resistance of the coolant in the IGBT chip. w This refers to the coolant temperature.

[0030] Optionally, calculating the junction temperature of the diode chip includes the following steps:

[0031] The conduction loss of the diode chip can be calculated using the following formula:

[0032]

[0033] Among them, P cond,Diode V represents the conduction loss of the diode chip, t is time, T0 is the chip's duty cycle, τ'(t) is the duty cycle of the diode chip, and V F (t) represents the forward voltage of the diode, V F0 Diode characteristic curve I F =f(V F Extend the tangent to the linear segment in the middle to intersect V. F The value at the intersection point, r F Diode characteristic curve I F =f(V F The slope of the tangent line to the linear segment in the equation, I m ω is the current amplitude, ω is the angular velocity, and m is the modulation ratio. The phase angle;

[0034] The switching loss of a diode chip can be calculated using the following formula:

[0035]

[0036] Among them, P sw,Diode f represents the switching loss of the diode chip. sw E is the switching frequency. on (I nom V nom E represents the typical start-up loss under operating conditions. off (I nom V nom V represents the typical turn-off loss under operating conditions. dc Battery voltage;

[0037] The junction temperature of the diode chip can be calculated using the following formula:

[0038]

[0039] Among them, Tj DIode P is the junction temperature of the diode chip. Diode R represents the total loss of the diode chip. th,Diode T is the thermal resistance of the coolant in the diode chip. w This refers to the coolant temperature.

[0040] Optional adjustments to the water pump speed and IGBT switching frequency include:

[0041] Determine if the junction temperature of the power module corresponding to the current coolant flow rate exceeds the junction temperature limit, and select the extent to which the switching frequency is reduced based on the exceeded junction temperature limit;

[0042] Determine the junction temperature range of the power module corresponding to the current coolant flow rate, and then determine the water pump speed based on the junction temperature range.

[0043] Optionally, after adjusting the pump speed and IGBT switching frequency, the flow rate classification, boundary value junction temperature measurement, junction temperature calculation and adjustment steps are re-executed based on the adjusted pump speed and switching frequency.

[0044] By actively adjusting the IGBT switching frequency and increasing the vehicle's water pump speed after the junction temperature-limited torque is reached, the junction temperature is reduced, preventing further junction temperature-limited torque. Simultaneously, the technical solution provided by this invention adds methods to reduce the junction temperature of the power module, optimizes the over-temperature protection strategy for the power module, further enhances hardware safety, and allows the water pump to operate at a low speed, saving energy.

[0045] In addition, the present invention also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the over-temperature protection method described in any of the above claims.

[0046] In addition, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the over-temperature protection method described in any of the above claims.

[0047] Furthermore, the present invention also provides a motor vehicle having a motor controller, wherein the motor controller performs over-temperature protection on its power module using any of the over-temperature protection methods described above to prevent the junction temperature of the power module from becoming too high;

[0048] Or the motor vehicle has the aforementioned computer equipment;

[0049] Alternatively, the motor vehicle may have the aforementioned computer-readable storage medium, and the computer program, when executed by a processor, implements the over-temperature protection method described in any of the preceding claims.

[0050] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and accompanying drawings. The preferred embodiments or means of the present invention will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. In addition, each of these features, elements and components appearing in the following text and drawings is a plurality of, and different symbols or numbers are used for convenience of representation, but all represent parts with the same or similar construction or function. Attached Figure Description

[0051] The present invention will be further described below with reference to the accompanying drawings:

[0052] Figure 1 This is a schematic diagram of the process in an embodiment of the present invention. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be explained and described below with reference to the accompanying drawings. However, the following embodiments are only preferred embodiments of the present invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present invention.

[0054] The terms "an embodiment," "example," or "trademark" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this patent. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0055] Example:

[0056] like Figure 1 As shown, this embodiment provides an over-temperature protection method for hybrid electric vehicles, plug-in hybrid electric vehicles, range-extended electric vehicles, and pure electric vehicles. These types of vehicles are all equipped with a motor, a battery pack that provides power to the motor, and a motor controller that controls the motor. They are also equipped with a water pump and cooling channels for cooling the battery, motor, and motor controller. The motor controller uses the over-temperature protection method provided in this embodiment to protect its power module from over-temperature, preventing the power module junction temperature from becoming too high. The over-temperature protection method provided in this embodiment includes the following steps:

[0057] Flow rate classification: Obtain the current coolant flow rate and determine the current water pump speed based on the current coolant flow rate and the coolant flow rate threshold. The water pump speed is classified by the threshold value.

[0058] Junction Temperature Calculation at Boundary Values: This step calculates the junction temperature of the power module corresponding to each boundary value of the coolant flow rate based on the operating parameters of the three electrical components (motor, electronic control, and battery). These operating parameters include, but are not limited to, the following: three-phase duty cycle, current, battery voltage, motor speed, inlet coolant temperature, and IGBT switching frequency. These parameters are essential for calculating the junction temperature of the power module. In this step, the conduction loss of the IGBT chip is first calculated for each bridge arm using the following formula:

[0059]

[0060] Among them, P cond,IGBT Let τ(t) represent the conduction loss of the IGBT chip, t be time, and T0 be the chip's duty cycle. Each phase's upper or lower IGBT operates for only half a cycle within one cycle. τ(t) represents the duty cycle of the IGBT chip. ce (t) represents the voltage between the collector and emitter of the IGBT, where V ce It can also be obtained by referring to tables from specifications or measured data. V ce0For IGBT output characteristic curve I c =f(V ce Extend the tangent to the linear segment in the middle to intersect V. ce The value at the intersection point, r ce For IGBT output characteristic curve I c =f(V ce The slope of the tangent line in the linear segment of the IGBT and the output characteristic curve of the IGBT are common technical knowledge known to those skilled in the art, and will not be elaborated here. m ω is the current amplitude, ω is the angular velocity, and m is the modulation ratio. The phase angle;

[0061] Then, calculate the switching losses of the IGBT chip for each bridge arm using the following formula:

[0062]

[0063] Among them, P SW,IGBT f represents the switching loss of the IGBT chip. sw E is the switching frequency. on (I nom V nom E represents the typical start-up loss under operating conditions. off (I nom V nom The turning-off loss under typical operating conditions is given. The turning-on or turning-off losses under typical operating conditions are common technical knowledge to those skilled in the art and will not be elaborated upon here. dc This refers to the battery voltage. The switching losses of the IGBT chip can also be obtained from the datasheet or by referring to tables based on measured data.

[0064] Then, the junction temperature of the IGBT chip is calculated for each bridge arm according to the following formula:

[0065]

[0066] Among them, Tj IGBT P is the junction temperature of the IGBT chip. IGBT R represents the total loss of the IGBT chip. th,IGBT T represents the thermal resistance of the coolant in the IGBT chip. w The temperature is the coolant temperature. The thermal resistance R of the coolant in the IGBT chip is... th,IGBT The thermal resistance R of the IGBT chip is negatively correlated with the coolant flow rate; that is, the higher the coolant flow rate, the lower the thermal resistance R of the IGBT chip. th,IGBT The smaller.

[0067] The junction temperature of the diode chip is calculated in the same way. First, the conduction loss of the diode chip is calculated for each bridge arm according to the following formula:

[0068]

[0069] Among them, P cond,Diode V represents the conduction loss of the diode chip, t is time, T0 is the chip's duty cycle, τ'(t) is the duty cycle of the diode chip, and V F (t) represents the forward conduction voltage of the diode, which can also be obtained from the datasheet or by referring to a table based on measured data. V F0 Diode characteristic curve I F =f(V F Extend the tangent to the linear segment in the middle to intersect V. F The value at the intersection point, r F Diode characteristic curve I F =f(V F The slope of the tangent line to the linear segment in the equation, I m ω is the current amplitude, ω is the angular velocity, and m is the modulation ratio. The phase angle;

[0070] Then, calculate the switching losses of the diode chips for each bridge arm using the following formula:

[0071]

[0072] Among them, P sw,Diode f represents the switching loss of the diode chip. sw E is the switching frequency. on (I nom V nom E represents the typical start-up loss under operating conditions. off (I nom V nom V represents the typical turn-off loss under operating conditions. dc The switching losses of the diode chip can be obtained from the datasheet or by referring to a table based on the battery voltage or measured data.

[0073] Then, the junction temperature of the diode chip is calculated for each bridge arm according to the following formula:

[0074]

[0075] Among them, Tj DIode P is the junction temperature of the diode chip. Diode R represents the total loss of the diode chip. th,Diode T is the thermal resistance of the coolant in the diode chip. w The temperature is the coolant temperature. The thermal resistance R of the coolant in the diode chip is... th,Diode The thermal resistance R of the diode chip is negatively correlated with the coolant flow rate; that is, the higher the coolant flow rate, the lower the thermal resistance R of the diode chip. th,Diode The smaller.

[0076] After calculating the junction temperature of the IGBT chip and the junction temperature of the diode chip in each bridge arm, the larger of the two values ​​is taken as the junction temperature of the bridge arm. Among all the junction temperatures of the bridge arms, the maximum value of the junction temperature is taken as the junction temperature of the power module.

[0077] Junction temperature calculation: Based on the current coolant flow rate, the coolant flow rate threshold corresponding to the current pump speed, and the power module junction temperature corresponding to the threshold value, the power module junction temperature corresponding to the current coolant flow rate is calculated using the following formula:

[0078] Tj = Tj n +(Tj n+1 -Tj n ) / (L n+1 -L n )*(LL n )

[0079] Where Tj is the junction temperature of the power module corresponding to the current coolant flow rate, and n is the current water pump speed and the corresponding speed boundary value number. n The junction temperature of the power module corresponds to the cutoff value of the coolant flow rate, where L is the current coolant flow rate and Ln is the cutoff value of the coolant flow rate. For example, n = 2 indicates that the current water pump speed is 2. L2 represents the starting flow rate value at speed 2, which is the second cutoff value. TJ2 represents the junction temperature of the power module corresponding to the starting flow rate value at speed 2. L3 represents the ending flow rate value at speed 2, which is the third cutoff value, and also the starting flow rate value at speed 3. TJ3 represents the junction temperature of the power module corresponding to the ending flow rate value at speed 2. By using interpolation to calculate the junction temperature of the power module, the accuracy of the junction temperature calculation is improved, avoiding the situation where the estimated junction temperature is lower than the actual junction temperature at low flow rates, thus protecting the module safety.

[0080] Adjustment: The junction temperature torque limit is obtained based on the junction temperature of the power module corresponding to the motor speed and the current coolant flow rate. The junction temperature torque limit is determined by a combination of table lookup and interpolation. Specifically, in this embodiment, the relationship between the motor speed, the junction temperature of the power module corresponding to the current coolant flow rate, and the junction temperature torque limit is shown in the following table:

[0081]

[0082] For example, if the current junction temperature Tj of the power module is 147.8℃ and the motor speed is 4000r / min, then the junction temperature torque limit is calculated to be 317.6Nm by interpolation after looking up the table.

[0083] It should be noted that this embodiment targets compact vehicles, including compact sedans and compact SUVs. When dealing with other vehicle types such as mid-size and large-size vehicles, the junction temperature torque limit can be adaptively adjusted by those skilled in the art during calibration and debugging based on the actual vehicle type. The adjustment method can employ a general junction temperature estimation method based on model and bench calibration, which is prior art known in the art and is not limited here. Those skilled in the art should understand that the junction temperature torque limit values ​​in this table are merely preferred embodiments in this case and are not intended to limit the technical solution.

[0084] Then, based on the obtained junction temperature and torque limits, the pump speed and IGBT switching frequency are adjusted, including:

[0085] The system determines if the junction temperature of the power module corresponding to the current coolant flow rate exceeds a specified junction temperature limit, and then adjusts the reduction in switching frequency based on this limit. There are several junction temperature limits, and the corresponding IGBT switching frequencies for different junction temperatures are shown in the table below.

[0086] Junction temperature Switching frequency 140℃ 10kHz 145℃ 9kHz 150℃ 8kHz

[0087] The system determines the junction temperature range of the power module corresponding to the current coolant flow rate, and then determines the water pump speed based on this range. Specifically, in this embodiment, the relationship between the junction temperature range and the water pump speed is shown in the following table:

[0088]

[0089]

[0090] It should also be noted that this embodiment targets compact vehicles, including compact sedans and compact SUVs. When dealing with other vehicle types such as mid-size and large-size vehicles, the relationship between the junction temperature limit and the IBGT switching frequency, as well as the relationship between the junction temperature range and the water pump speed, can be adaptively adjusted by those skilled in the art during calibration based on the actual vehicle type. Specific adjustment methods are existing technologies known in the art and are not limited here. Those skilled in the art should understand that the maximum torque limit in this table is merely a preferred embodiment and not a limitation on the technical solution.

[0091] The technical solution provided in this embodiment enables dynamic estimation of the power module junction temperature, providing more effective protection against excessively high junction temperatures, improving the limitation of junction temperature torque, and fully utilizing the hardware's current capability. After limiting the junction temperature torque, the switching frequency of the IGBT is actively adjusted and the vehicle's water pump speed is increased to lower the junction temperature, avoid junction temperature torque limitation, and further enhance hardware safety.

[0092] After adjusting the water pump speed and IGBT switching frequency, the flow rate grading, junction temperature threshold calculation, junction temperature calculation, and adjustment steps are re-executed based on the adjusted water pump speed and switching frequency. For example, when the calculated power module junction temperature is greater than or equal to the junction temperature limit of 140℃, the IGBT switching frequency is reduced from 10kHz to 9kHz. Re-executing the flow rate grading, junction temperature threshold calculation, junction temperature calculation, and adjustment steps yields a recalculated power module junction temperature of 144.2℃. Re-referencing the table and interpolating, the junction torque limit is calculated to be 343.2Nm, thus reducing the torque limitation based on junction temperature. When the power module junction temperature Tj is 147.8℃, the coolant flow rate corresponding to the water pump speed is 16L / min. Based on this, re-executing the flow rate grading, junction temperature threshold calculation, junction temperature calculation, and adjustment steps yields a recalculated power module junction temperature Tj of 134.6℃. The power module junction temperature decreases, therefore the torque limitation based on junction temperature is removed.

[0093] By actively adjusting the IGBT switching frequency and increasing the vehicle's water pump speed after the junction temperature-limited torque, the junction temperature is reduced, preventing further junction temperature-limited torque and creating a closed-loop over-temperature protection system. Simultaneously, methods to reduce the power module junction temperature are added, optimizing the power module over-temperature protection strategy. This further enhances hardware safety while allowing the water pump to operate at a lower speed, saving energy.

[0094] Meanwhile, this embodiment also provides a computer device, including a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the point cloud semantic segmentation method described above.

[0095] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. Accordingly, the computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can implement the methods of any of the above embodiments. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0096] Furthermore, this embodiment also provides a motor vehicle with a motor controller, which uses the aforementioned over-temperature protection method to protect its power module from over-temperature, preventing the junction temperature of the power module from becoming too high.

[0097] Or the motor vehicle has the aforementioned computer equipment;

[0098] The vehicle or motor vehicle has the aforementioned computer-readable storage medium, and the computer program, when executed by a processor, implements the aforementioned over-temperature protection method.

[0099] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. An over-temperature protection method, characterized in that, The motor controller uses the over-temperature protection method to protect its power module from excessively high junction temperatures. The over-temperature protection method includes the following steps: Flow rate classification: Obtain the current coolant flow rate and determine the current water pump speed based on the current coolant flow rate and the coolant flow rate threshold value. The water pump speed is classified by the threshold value. Junction temperature calculation based on boundary values: The junction temperature of the power module corresponding to each boundary value of the coolant flow is calculated based on the three operating parameters, including the switching frequency of the insulated gate bipolar transistor. Junction temperature calculation: Based on the current coolant flow rate, the coolant flow rate threshold corresponding to the current pump speed, and the power module junction temperature corresponding to the threshold value, the power module junction temperature corresponding to the current coolant flow rate is calculated using the following formula: Tj = Tj n +（ Tj n+1 - Tj n ） / （ L n+1 - L n ）*（ L - L n ） in, Tj This represents the junction temperature of the power module corresponding to the current coolant flow rate. n This represents the current pump speed and the corresponding boundary value number. Tj n The junction temperature of the power module corresponding to the cutoff value of the coolant flow rate. L This represents the current coolant flow rate. Ln This is the dividing value for coolant flow rate; Adjustment: Obtain the junction temperature torque limit based on the power module junction temperature corresponding to the motor speed and the current coolant flow rate, and adjust the water pump speed and the switching frequency of the insulated gate bipolar transistor.

2. The over-temperature protection method according to claim 1, characterized in that, Calculating the junction temperature of the power module corresponding to each threshold value of the coolant flow rate involves the following steps: Calculate the junction temperature of the insulated gate bipolar transistor chip and the junction temperature of the diode chip for each bridge arm, and take the larger of the two values ​​as the junction temperature of the bridge arm. The maximum junction temperature among all bridge arms is taken as the power module junction temperature.

3. The over-temperature protection method according to claim 2, characterized in that, Calculating the junction temperature of an insulated-gate bipolar transistor chip involves the following steps: The conduction loss of an insulated-gate bipolar transistor chip can be calculated using the following formula: in, P cond,IGBT This refers to the conduction loss of an insulated-gate bipolar transistor (IGBT) chip. t For time, T 0 represents the chip's duty cycle. This refers to the duty cycle of an insulated-gate bipolar transistor chip during operation. V ce ( t () represents the voltage between the collector and emitter of an insulated-gate bipolar transistor. V ce0 Output characteristic curve of an insulated gate bipolar transistor I c = f ( V ce Extend the tangent line of the linear segment to the line... V ce The value at the intersection, r ce Output characteristic curve of an insulated gate bipolar transistor I c = f ( V ce The slope of the tangent line to the linear segment in the equation. I m The current amplitude, ω ω is the angular velocity, m is the modulation ratio. The phase angle; The switching losses of an insulated-gate bipolar transistor (IGBT) chip can be calculated using the following formula: in, P SW,IGBT For the switching losses of insulated-gate bipolar transistor chips, f sw For switching frequency, E on ( I nom , V nom This represents the typical start-up loss under operating conditions. E off ( I nom , V nom This represents the typical turn-off loss under operating conditions. V dc Battery voltage; The junction temperature of an insulated-gate bipolar transistor chip can be calculated using the following formula: in, Tj IGBT This refers to the junction temperature of an insulated-gate bipolar transistor chip. P IGBT This represents the total loss of an insulated-gate bipolar transistor chip. R th,IGBT The thermal resistance of the coolant in an insulated-gate bipolar transistor (IGBT) chip. T w This refers to the coolant temperature.

4. The over-temperature protection method according to claim 2, characterized in that, Calculating the junction temperature of a diode chip involves the following steps: The conduction loss of the diode chip can be calculated using the following formula: in, P cond,Diode This refers to the conduction loss of the diode chip. t For time, T 0 represents the chip's duty cycle. This refers to the duty cycle during diode chip operation. V F ( t () represents the forward voltage of the diode. V F0 Diode characteristic curve I F = f ( V F Extend the tangent line of the linear segment to the line... V F The value at the intersection, r F Diode characteristic curve I F =f(V F ) The slope of the tangent line in the middle linear segment. I m The current amplitude, ω ω is the angular velocity, m is the modulation ratio. The phase angle; The switching loss of a diode chip can be calculated using the following formula: in, P sw,Diode This refers to the switching losses of the diode chip. f sw For switching frequency, E on ( I nom , V nom This represents the typical start-up loss under operating conditions. E off ( I nom , V nom This represents the typical turn-off loss under operating conditions. V dc Battery voltage; The junction temperature of the diode chip can be calculated using the following formula: in, Tj DIode This refers to the junction temperature of the diode chip. P Diode This represents the total loss of the diode chip. R th,Diode The thermal resistance of the coolant in the diode chip is given. T w This refers to the coolant temperature.

5. The over-temperature protection method according to any one of claims 1 to 4, characterized in that, Adjusting the water pump speed and the switching frequency of the insulated-gate bipolar transistor include: Determine if the junction temperature of the power module corresponding to the current coolant flow rate exceeds the junction temperature limit, and select the extent to which the switching frequency is reduced based on the exceeded junction temperature limit; Determine the junction temperature range of the power module corresponding to the current coolant flow rate, and then determine the water pump speed based on the junction temperature range.

6. The over-temperature protection method according to claim 1, characterized in that, After adjusting the pump speed and the switching frequency of the insulated gate bipolar transistor, the flow rate classification, boundary value junction temperature measurement, junction temperature calculation and adjustment steps are re-executed based on the adjusted pump speed and switching frequency.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the over-temperature protection method according to any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the over-temperature protection method according to any one of claims 1 to 6.

9. A motor vehicle, characterized in that, The motor vehicle has a motor controller, which uses the over-temperature protection method according to any one of claims 1 to 6 to protect its power module from over-temperature, thereby preventing the junction temperature of the power module from becoming too high. Or the motor vehicle may have the computer equipment as described in claim 7; Alternatively, the motor vehicle may have a computer-readable storage medium as described in claim 8, wherein the computer program, when executed by a processor, implements the over-temperature protection method as described in any one of claims 1 to 6.

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