Heating control method and device of vehicle, vehicle and medium

Abstract

Embodiments of the present application provide a heating control method and device for a vehicle, the vehicle and a medium. The method comprises: during the process of driving motor active heating, the driving system detects the temperature of the driving motor controller power device in real time to ensure that it operates within a safe working range. When it is detected that the temperature of the power device is higher than a preset first temperature threshold, the switching loss of the power device is controlled to reduce the heat generation of the power device. Through the above method, the driving motor can also be continuously actively heated when the vehicle is in a stationary state, which not only improves the thermal management efficiency of the vehicle, but also enhances the reliability of the electric vehicle driving system and the user experience.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to a heating control method and device of a vehicle, a vehicle and a medium. BACKGROUND

[0002] With the popularity of electric vehicles, the performance and endurance of vehicles under low temperature conditions have become the focus of users, and the active heating method of the drive motor has emerged as the times require. However, in the stationary state of the vehicle, the active heating method of the drive motor cannot completely balance the heat of the Insulate-Gate Bipolar Transistor (IGBT) of the power device, which may cause the highest temperature of the power device to exceed the safety threshold and interrupt the heating.

[0003] The existing heating method of the drive system generates multiple high-frequency Pulse-width modulation (PWM) signals when it detects that the vehicle is in the parking state and receives a heating request, and outputs the multiple high-frequency PWM signals to the motor controller to control the motor controller to output high-frequency alternating current to the stator of the drive motor, so that the stator and rotor of the drive motor generate heat in the stationary state and conduct the heat to the device that initiates the heating request. This method means that the switching frequency of the power device is high when the vehicle is in the parking state, and the switching frequency is high, which still increases the switching loss and causes the temperature of the power device to rise, interrupting the heating.

[0004] In summary, it is a technical problem to be solved to provide a control method that can achieve continuous active heating of the drive motor when the vehicle is in the stationary state. SUMMARY

[0005] The embodiments of the present application provide a heating control method, device, vehicle and medium of a vehicle to achieve continuous active heating of the drive motor when the vehicle is in the stationary state and ensure the stability of the heating process.

[0006] In a first aspect, the embodiments of the present application provide a heating control method of a vehicle, comprising:

[0007] In the active heating process, the temperature of the power device is detected in real time;

[0008] If the temperature is higher than a preset first temperature threshold, the switching loss of the power device is controlled to reduce the temperature of the power device.

[0009] In a possible implementation, the control of the switching loss of the power device comprises:

[0010] controlling to reduce a pulse width modulation (PWM) switching frequency of the power device;

[0011] and / or,

[0012] by changing a space vector pulse width modulation (SVPWM) control mode of the power device, reducing a switching number in each switching period.

[0013] In a possible implementation, the controlling to reduce the PWM switching frequency of the power device comprises:

[0014] according to a preset time period, reducing the PWM switching frequency of the power device to a target frequency in the time period, the target frequency being a lowest working frequency of the PWM switching.

[0015] In a possible implementation, the current SVPWM modulation control mode of the power device is a seven-segment SVPWM modulation mode.

[0016] Correspondingly, the reducing the switching number in each switching period by changing the SVPWM modulation control mode of the power device comprises:

[0017] changing the SVPWM modulation control mode of the power device to a five-segment SVPWM modulation mode.

[0018] In a possible implementation, the method further comprises:

[0019] if it is detected that the temperature of the power device is still greater than the first temperature threshold, changing the SVPWM modulation control mode of the power device from the seven-segment SVPWM modulation mode to the five-segment SVPWM modulation mode.

[0020] In a possible implementation, the method further comprises:

[0021] if it is detected that the temperature of the power device is greater than a second temperature threshold, controlling to turn off the active heating, wherein the second temperature threshold is greater than the first temperature threshold, and the second temperature threshold is less than a highest working junction temperature of the power device.

[0022] In a possible implementation, the real-time detection of the temperature of the power device comprises:

[0023] real-time detection of the temperature of each transistor, and determination of a highest temperature in the plurality of temperatures as the temperature of the power device.

[0024] In a second aspect, an embodiment of the present application provides a heating control device of a vehicle, comprising:

[0025] The first processing module is configured to detect the temperature of the power device in real time during the active heating process.

[0026] The second processing module is configured to control the switching loss of the power device to reduce the temperature of the power device if the temperature is higher than the preset first temperature threshold.

[0027] In a third aspect, an embodiment of the present application provides a drive motor controller, comprising:

[0028] a memory, a processor and a power device;

[0029] The memory stores computer-executable instructions.

[0030] The processor executes the computer-executable instructions stored in the memory, so that the processor executes the first aspect and / or various possible implementation manners of the first aspect.

[0031] In a fourth aspect, an embodiment of the present application provides a vehicle, comprising: a main structure of the vehicle and the drive motor controller according to the third aspect.

[0032] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed by a processor, the computer-executable instructions are used to implement the first aspect and / or various possible implementation manners of the first aspect.

[0033] The heating control method, device, vehicle and medium provided by the embodiments of the present application can ensure that the power device of the drive motor controller operates within a safe working range by detecting the temperature of the power device of the drive motor controller in real time during the active heating process of the drive motor. When the temperature of the power device is detected to be higher than a preset first temperature threshold, the switching loss of the power device is controlled to reduce the heat generation of the power device. Through the above method, the power device can be protected from overheating damage, and the continuous active heating of the drive motor can be realized when the vehicle is static, and more efficient thermal management can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0035] Figure 1 A heating control method of a vehicle provided by the present application Figure 1 ;

[0036] Figure 2 A specific implementation manner of a heating control method of a vehicle provided by the present application Figure 1 ;

[0037] Figure 3 A schematic of a heating control method for a vehicle according to an embodiment of the present application Figure 2 ;

[0038] Fig. 4(a) is a detailed embodiment of a heating control method for a vehicle according to an embodiment of the present application Figure 2 ;

[0039] Fig. 4(b) is a detailed embodiment of a heating control method for a vehicle according to an embodiment of the present application Figure 3 ;

[0040] Figure 5 A schematic of a heating control device for a vehicle according to an embodiment of the present application

[0041] Figure 6 A schematic of a drive motor controller according to an embodiment of the present application

[0042] The above-described drawings illustrate embodiments of the present application in accordance with the practical examples, which will be described in more detail later. These drawings and detailed description are not intended to limit the scope of the present application in any way, but to explain the present application to one of ordinary skill in the art by reference to a particular embodiment. DETAILED DESCRIPTION

[0043] The exemplary embodiments will be described in detail herein with reference to the attached drawings. In the following description, like reference numerals refer to like elements, unless the context clearly dictates otherwise. The following description of exemplary embodiments is not intended to represent all embodiments in accordance with the present application. Rather, they are merely examples in accordance with some aspects of the present application as detailed in the appended claims.

[0044] First, the terms related to the present application are explained:

[0045] Pulse Width Modulation (PWM): It is an analog control method that changes the transistor conduction time according to the change in the corresponding load, thereby changing the output of the switching power supply. The transistor (full-controlled device such as IGBT, Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), etc.) works in a switching state, and when the transistor is triggered to turn on, the power supply voltage is applied to the motor; when the transistor is turned off, the DC power supply is disconnected from the motor. That is, by changing the conduction time of the transistor (i.e., adjusting the duty ratio), the motor voltage is adjusted, thereby performing speed control or adjusting the driving motor torque.

[0046] Space Vector Pulse Width Modulation (SVPWM): refers to the three-phase symmetrical sinusoidal wave voltage supply when the three-phase symmetrical motor stator ideal flux circle as the reference standard, with different switching mode of three-phase inverter to make appropriate switching, so as to form PWM wave, with the actual flux vector formed to track its accurate flux circle. This method considers the inverter system and asynchronous motor as a whole, according to how to produce circular rotating magnetic field to control the work of inverter.

[0047] Junction Temperature: refers to the actual working temperature of the semiconductor junction, i.e. PN junction, in electronic devices. The internal of semiconductor device is composed of multiple PN junctions.

[0048] Three-phase inverter: refers to an electronic device used to convert DC power into three-phase AC power. The basic structure includes a set of power switching devices such as IGBT or MOSFET, which are switched in a specific sequence and frequency to synthesize the required AC waveform. The inverter generates three-phase AC output by controlling the on and off time of each switch. Inverter uses SVPWM technology to optimize the selection and application of voltage vectors, which can improve the quality of output waveform, reduce harmonic distortion and improve the efficiency of the system.

[0049] Next, the application background of the present application is explained as follows:

[0050] The pure electric vehicle thermal management system uses the positive temperature coefficient (PTC) thermistor resistance to increase with temperature to heat the electric heater for heating when there is a heating demand. PTC thermistor has a low resistance at low temperature, which can quickly generate heat through current. When the temperature rises to a certain extent, the resistance will increase rapidly, thereby limiting the passage of current, achieving the effect of self-regulating temperature. PTC electric heater obtains electric energy from the battery of the vehicle to generate heat. The battery capacity of electric vehicles is limited, and any additional power consumption will reduce the amount of electricity available for driving the vehicle, affecting the vehicle's endurance.

[0051] With the popularization of electric vehicles, the performance and endurance of vehicles under low temperature conditions have become the focus of users, and the active heating method of the drive motor has emerged as the times require. This method uses the heat generated by the drive motor in the stationary state to transfer to the battery pack and the cabin through the cooling liquid, thereby improving the working temperature of the battery and the comfort of the vehicle. Specifically, the electric vehicle drive system obtains the heat generation power of the power device according to the active heating order, determines the positive and negative symmetrical alternating heating current, and applies it to the direct axis of the drive system motor to realize balanced heating of the power device of the electric vehicle drive system. However, in the stationary state of the vehicle, the active heating method of the drive motor cannot completely balance the heat generation of the power device IGBT tube, which may cause the highest temperature of the power device to exceed the safety threshold and interrupt the heating.

[0052] The existing heating method of the drive system generates multiple high-frequency PWM signals when it detects that the vehicle is in the parking state and receives a heating request, and outputs the multiple high-frequency PWM signals to the motor controller to control the motor controller to output a high-frequency alternating current to the stator of the drive motor, so that the stator and rotor of the drive motor generate heat in the stationary state and conduct the heat to the device that initiates the heating request. This method means that the switching frequency of the power device is high when the vehicle is in the parking state, and the switching frequency is high, which still causes the switching loss to increase, thereby causing the temperature of the power device to rise and interrupting the heating.

[0053] In summary, effectively solving the problem that the active heating of the drive motor cannot completely balance the heat generation of the power module IGBT tube when the vehicle is in the stationary state, and providing a control method that can realize continuous active heating of the drive motor when the vehicle is in the stationary state, is a technical problem that needs to be solved.

[0054] Based on the above technical problems, the inventor found that the main reasons for the heat generation of the power device include conduction loss and switching loss, and the heat generation power of the power device can be directly obtained according to the active heating demand of the drive motor, and the size of the control current is directly determined, i.e. the size of the conduction loss. Therefore, the heat generation of the power device can be reduced by reducing the switching loss of the power device during operation to solve the above technical problems. Based on this, the present application provides a heating control method, device, vehicle and medium for a vehicle to achieve continuous active heating of the drive motor when the vehicle is in the stationary state, ensure the stability of the heating process, and realize more efficient thermal management.

[0055] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of the present application will be described below with reference to the drawings.

[0056] Figure 1 A heating control method of a vehicle Figure 1 , Figure 2 Embodiment of a heating control method of a vehicle Figure 1 As shown in Figure 2 , the method comprises:

[0057] S101, detecting the temperature of the power device in real time during active heating.

[0058] In this step, the drive motor controller power device is usually composed of six IGBT tubes to form a three-phase inverter circuit to control the operation of the drive motor. The six IGBT tubes are configured as a three-phase bridge circuit, each phase consisting of two IGBT tubes, one connected to the positive DC bus, i.e. the upper bridge arm; one connected to the negative DC bus, i.e. the lower bridge arm. Specifically, the IGBT tube of the U-phase upper bridge arm controls the positive current of the U-phase; the IGBT tube of the U-phase lower bridge arm controls the negative current of the U-phase; the IGBT tube of the V-phase upper bridge arm controls the positive current of the V-phase; the IGBT tube of the V-phase lower bridge arm controls the negative current of the V-phase; the IGBT tube of the W-phase upper bridge arm controls the positive current of the W-phase; the IGBT tube of the W-phase lower bridge arm controls the negative current of the W-phase. The IGBT tubes work in coordination to generate the required three-phase alternating current to drive the motor.

[0059] It should be noted that the IGBT tube in the present application is only used for illustration, and in actual application it can be a MOS tube or other types, and the present application does not make specific limitation on the specific form and type of the entity device involved.

[0060] Specifically, in the process of realizing active heating, in response to the active heating instruction of the drive motor, the active heating request power of the drive motor is obtained according to the heating instruction, and the size of the alternating heating current required to be applied on the direct axis of the drive motor is further determined. Because the active heating of the drive motor cannot generate unexpected torque to make the motor generate driving force, the cross-axis current of the drive motor needs to be set to 0, and the direct-axis current is adjusted to make the motor winding heat up, so as to make the drive motor controller power device of the electric vehicle drive system heat up evenly.

[0061] However, when the vehicle is stationary, on the one hand, the three-phase alternating current of the drive motor is unevenly distributed, resulting in uneven current through the IGBT tube and uneven heating of the IGBT tube; on the other hand, the drive motor itself has good heat conduction performance, and the drive motor controller power device heats up quickly. That is, the method of passing alternating heating current through the direct axis of the motor of the electric vehicle drive system to heat the drive motor controller power device cannot achieve balanced heating of the power device. Therefore, in order to avoid damage to the power device due to excessive local temperature, and thus unable to realize the continuous active heating function of the drive motor, the electric vehicle drive system will detect the temperature of the drive motor controller power device in real time. Specifically, the temperature of each crystal IGBT tube is detected in real time, and the highest temperature among the multiple temperatures is determined as the temperature of the drive motor controller power device.

[0062] S102, if the temperature is higher than the preset first temperature threshold, the switching loss of the power device is controlled to reduce the temperature of the power device.

[0063] In this step, the three-phase alternating current of the drive motor generates heat when passing through the motor controller power device, causing the junction temperature to rise. The highest working junction temperature is used to indicate the highest temperature that the PN junction inside the power device can withstand under normal working conditions. Exceeding this temperature may cause the power device to degrade, accelerate aging, and even cause permanent damage or failure. This temperature is usually provided by the power device manufacturer. Therefore, the preset first temperature threshold helps the junction temperature of the power device to take appropriate adjustment and protection measures before reaching the highest working junction temperature, thereby ensuring the safe operation and long-term reliability of the power device.

[0064] The preset of the first temperature threshold needs to consider the characteristics of the power device, the highest working junction temperature, the response speed of the electric vehicle drive system to temperature changes, and the operation requirements of the drive motor, etc. A too high first temperature threshold means that the electric vehicle drive system is not sensitive enough to temperature changes, which may not be able to effectively reduce the temperature of the power device in time, thereby threatening the safety and reliability of the entire electric vehicle drive system. On the contrary, a too low first temperature threshold may trigger unnecessary protection actions causing system misjudgment, or frequently adjust the working state of the power device, thereby affecting the normal operation and performance of the drive motor, and reducing the efficiency and stability of the overall system.

[0065] The first temperature threshold value can be set to be about 60°C lower than the maximum operating junction temperature. Specifically, assuming that the maximum operating junction temperature of the IGBT tube of the motor controller power device is 150°C, the first preset temperature threshold value can be 85°C, 87°C, 90°C, 93°C, 95°C, etc. It should be noted that the maximum operating junction temperature of the IGBT tube of 150°C and the value of the first temperature threshold value are only used for illustration, and the application is not limited. In actual work, the setting of the first temperature threshold value needs to be adjusted according to the actual situation of the maximum operating junction temperature of the power device, so as to ensure that the protection measures can be taken in time and effectively before the power device reaches the dangerous level, and to avoid unnecessary interference and influence on the system caused by too frequent protection actions.

[0066] When the vehicle is in a stationary state, the method of passing the alternating heating current through the direct axis of the motor of the electric vehicle driving system to heat the power device of the driving motor controller can cause the power device of the driving motor controller to heat unevenly. In this case, the driving motor controller power device is prone to reach the maximum temperature protection point and cause the driving motor controller to stop, affecting the continuous active heating of the driving motor. The reasons for the heating of the power device mainly include conduction loss heating and switching loss heating.

[0067] Conduction loss generally refers to the energy loss of the power device in the conduction state due to the resistance of the device itself during the conduction of the device. That is, when the current passes through the device, a certain power loss is generated due to the conduction resistance (usually referred to as on-state resistance or conduction voltage drop) of the device. The size of the conduction loss is proportional to the square of the current, because the power loss can be represented as the square of the current multiplied by the conduction resistance.

[0068] Switching loss includes turn-on loss and turn-off loss, which refers to the energy loss caused by the overlap of voltage and current when the power device is switched. Specifically, the turn-on loss refers to the energy loss caused by the overlap of voltage and current when the power device is switched from the off state to the on state, i.e., the voltage gradually decreases to near zero, while the current rapidly rises to the load current. The turn-off loss refers to the energy loss caused by the overlap of voltage and current when the power device is switched from the on state to the off state, i.e., the current gradually decreases to zero, but the voltage rapidly rises to the power supply voltage. As shown in FIG. 1, the turn-on loss and the turn-off loss correspond to the region where the voltage and current curves cross, i.e., the time period when the voltage and current exist at the same time, and the conduction loss corresponds to the continuous voltage drop region when the current passes through the power device. Figure 3

[0069] ​The heating power of the power device can be directly obtained according to the active heating demand of the driving motor, and directly determines the size of the control current, that is, the size of the switching loss. Therefore, the heating of the power device can be reduced by reducing the switching loss of the power device during operation, and the driving motor can continuously perform active heating. The size of the switching loss is related to the switching frequency, the switching speed of the power device, and the waveforms of the voltage and current. The higher the switching frequency, the greater the switching loss.

[0070] Specifically, if the temperature of the power device of the driving motor controller is higher than the preset first temperature threshold, the switching loss of the power device is controlled to be reduced. In this scheme, the way of controlling the switching loss of the power device includes: controlling the PWM switching frequency of the power device and / or reducing the number of switches in each switching cycle by changing the SVPWM modulation control mode of the power device, so as to reduce the energy loss of the power device in the switching process at a reduced temperature, thereby reducing the working junction temperature of the power device, improving the stability and reliability of the system, prolonging the service life of the power device, and optimizing the operation efficiency of the driving motor.

[0071] The heating control method of the vehicle provided in the present application can detect the temperature of the power device in real time during the continuous active heating of the driving motor, and ensure that the power device operates within a safe working range. Specifically, in response to the active heating instruction of the driving motor, the driving system obtains the active heating request power according to the heating instruction, determines the size of the alternating current heating current to be applied, and applies the alternating current heating current to the direct axis of the motor of the electric vehicle driving system, so as to uniformly heat the power device of the driving motor controller of the electric vehicle driving system. However, due to the uneven distribution of three-phase alternating current in the stationary state of the vehicle, the IGBT tube may be heated unevenly. When the driving system detects that the temperature of the power device is higher than the preset first temperature threshold, the switching loss of the power device is controlled to be reduced, so as to reduce the temperature of the power device and avoid damage to the device caused by excessive local temperature. Through the above method, the continuous active heating function of the driving motor in the stationary state of the vehicle is realized, the stability and reliability of the driving system are improved, the service life of the power device is prolonged, and the driving system can meet the active heating demand of the driving motor while maintaining high operation efficiency and stability.

[0072] Figure 2 A schematic diagram of the heating control method of the vehicle provided in the present application Figure 2 , Fig. 4(a) is a specific embodiment of the heating control method of the vehicle provided in the present application Figure 3 , Fig. 4(b) is a specific embodiment of the heating control method of the vehicle provided in the present application Figure 3 As shown in Figure 1 , the present embodiment is Figure 5The heating control method of the vehicle is described in detail based on the embodiments, and the control of reducing the switching loss of the power device includes:

[0073] The first case: according to the preset time period, the PWM switching frequency of the power device is reduced to the target frequency within the time period, and the target frequency is the lowest working frequency of the PWM switching.

[0074] In this case, the PWM switching frequency refers to the number of times the IGBT driving motor controller power device switches in a unit of time. Higher switching frequency can usually achieve more precise control, but it will also increase the switching loss. The lowest working frequency of the PWM switching refers to the lowest switching frequency at which the power device can stably work under the premise of not affecting its function and performance and maintaining normal working state. If the PWM switching frequency is lower than the lowest working frequency, the power device may not work normally or its performance will be greatly reduced. Therefore, reducing the PWM switching frequency to the lowest working frequency can reduce the switching loss and thus reduce the temperature of the device.

[0075] Specifically, during the process of continuously actively heating the driving motor, it is assumed that the PWM switching frequency of the driving motor controller power device is , the driving motor continuously actively heating time is , and the current SVPWM modulation control mode of the driving motor controller power device is the seven-segment SVPWM modulation mode under normal circumstances. Therefore, during the process of continuously actively heating the driving motor, the heating duration , the switching times of the driving motor controller power device are . If the temperature of the power device is higher than the preset first temperature threshold, the PWM switching frequency of the power device is reduced to the target frequency within a certain time period, and the target frequency is the lowest working frequency of the PWM switching. At this time, the heating duration , the switching times of the driving motor controller power device are . Obviously, , the method of reducing the PWM switching frequency of the power device to the target frequency within the time period reduces the PWM switching frequency, achieves the purpose of controlling the reduction of the switching loss of the power device, and reduces the temperature of the power device.

[0076] The second case: the SVPWM modulation control mode of the power device is changed to the five-segment SVPWM modulation mode.

[0077] In this case, the main idea of SVPWM is to form three-phase PWM wave output by switching different switching modes of three-phase inverter, and to obtain the target stator current by controlling the phase voltage. In the SVPWM control algorithm, according to the switching times of PWM signal in a cycle, it can be divided into seven-segment SVPWM and five-segment SVPWM. Seven-segment SVPWM is the traditional SVPWM implementation method, which divides the output voltage of the three-phase motor into seven vectors, namely positive maximum vector, positive medium vector, positive minimum vector, negative minimum vector, negative medium vector, negative maximum vector and zero vector. Seven-segment SVPWM realizes smoother voltage output by applying zero vector at the beginning and end of each cycle, and alternately applying effective vector in the middle. As shown in FIG. 4(a), seven-segment SVPWM wave is symmetrical and has less harmonic content, with 6 switching times in each switching cycle. Five-segment SVPWM divides the output voltage of the three-phase motor into five vectors, namely positive maximum vector, positive medium vector, zero vector, negative medium vector and negative maximum vector, and applies effective vector at the beginning and end of each cycle, and inserts zero vector in the middle. Five-segment SVPWM and seven-segment SVPWM maintain the same sequence arrangement of each phase switching in each sector state, as shown in FIG. 4(b), five-segment SVPWM has 4 switching times in each switching cycle.

[0078] Specifically, in the process of driving motor to realize continuous active heating, assuming that the PWM switching frequency of the power device of the driving motor controller is , the continuous active heating time of the driving motor is , and the current SVPWM modulation control mode of the power device of the driving motor controller is seven-segment SVPWM modulation mode under normal circumstances. Therefore, in the process of driving motor to realize continuous active heating, the switching times of the power device of the driving motor controller in the heating time is . If the temperature of the power device is higher than the first preset temperature threshold, the SVPWM modulation control mode of the power device is changed to five-segment SVPWM modulation mode. At this time, the switching times of the power device of the driving motor controller in the heating time is . Obviously, the method of changing the SVPWM modulation control mode of the power device to five-segment SVPWM modulation mode reduces the PWM switching frequency, achieves the purpose of controlling and reducing the switching loss of the power device to reduce the temperature of the power device.

[0079] The third case is:

[0080] S301, in the process of actively heating, in response to the active heating instruction of the driving motor, the driving motor active heating request power is obtained according to the heating instruction.

[0081] S302, further determine the size of the alternating heating current needed to be applied on the direct axis of the driving motor.

[0082] In this step, the alternating heating current needed to be applied on the direct axis of the driving motor is positive-negative symmetric, and the waveform has symmetry in the positive half cycle and the negative half cycle, that is, the average value of the positive-negative symmetric alternating heating current in a complete cycle is zero, but the same heat effect is generated in each half cycle. The positive half cycle and the negative half cycle of the positive-negative symmetric alternating heating current have equal amplitude and opposite direction, which ensures that the energy received by the load in each cycle is constant. Since the heat generated by the current through the load in each half cycle is proportional to the square of the current, even if the current direction is reversed in the negative half cycle, the heat generated is still positive. Therefore, the positive-negative symmetric alternating heating current can use standard alternating power without additional rectification or filtering equipment, thereby reducing the cost.

[0083] S303, the driving motor continues to actively heat and detects the power device temperature in real time.

[0084] In this step, the determined positive-negative symmetric alternating heating current is applied on the direct axis of the driving motor, and the control driving motor cross-axis current is zero, at this time the electronic winding generates heat, and the driving motor controller power device also generates a certain amount of heat.

[0085] S304, the temperature of the power device is judged in real time whether it is greater than the first temperature threshold.

[0086] S305, if the temperature of the power device is higher than the preset first temperature threshold, the switching loss of the power device is controlled to be reduced to reduce the temperature of the power device.

[0087] In this step, when the vehicle is in a static state, on the one hand, the three-phase alternating current of the driving motor is unevenly distributed, resulting in uneven current through the IGBT tube, and the IGBT tube heats unevenly; on the other hand, the driving motor itself has good heat conduction performance, and the driving motor controller power device heats up quickly. That is, the method of heating the driving motor controller power device by passing the alternating heating current through the direct axis of the motor of the electric vehicle driving system cannot achieve balanced heating of the power device. Therefore, relevant measures need to be taken to reduce the temperature of the power device and prevent the driving motor controller power device from heating unevenly, resulting in rapid local temperature rise and shutdown. Conversely, if the temperature of the power device is not detected to be higher than the first temperature threshold, it indicates that the vehicle is in a non-static state, the IGBT tube of the driving motor controller power device heats evenly, or the vehicle has been in a static state, although the IGBT tube of the driving motor controller power device heats unevenly, but its highest temperature does not reach the first temperature threshold, at this time, the driving motor can still continue to actively heat.

[0088] S3051、According to the preset time period, the PWM switching frequency of the power device is reduced to the target frequency within the time period.

[0089] The implementation principle and technical effect of this step are similar to those of the above-mentioned first case, and will not be repeated here.

[0090] S3052, judge whether the temperature of the power device is still greater than the first temperature threshold.

[0091] S3053, if it is detected that the temperature of the power device is still greater than the first temperature threshold, the SVPWM modulation control mode of the power device is changed from the seven-segment SVPWM modulation mode to the five-segment SVPWM modulation mode.

[0092] The implementation principle and technical effect of this step are similar to those of the above-mentioned second case, and will not be repeated here.

[0093] Specifically, on the basis of reducing the PWM switching frequency of the power device to the target frequency, the SVPWM modulation control mode of the power device is changed from the seven-segment SVPWM modulation mode to the five-segment SVPWM modulation mode. At this time, the heating time , the switching times of the driving motor controller power device . Obviously, ; , the purpose of further reducing the PWM switching frequency, further reducing the switching loss of the power device, and further reducing the temperature of the power device is achieved.

[0094] S306, judge whether the temperature of the power device is greater than the second temperature threshold.

[0095] S307, if it is detected that the temperature of the power device is greater than the second temperature threshold, then controlling to turn off the active heating; wherein the second temperature threshold is greater than the first temperature threshold, and the second temperature threshold is less than the maximum operating junction temperature of the power device.

[0096] In this step, to ensure safe operation, the second temperature threshold is less than the maximum operating junction temperature of the power device, to provide a safety margin to prevent the device from overheating and damaging under extreme conditions. The first temperature threshold is a preliminary warning line to detect whether the temperature of the power device is starting to approach an unsafe level. When the temperature exceeds the first temperature threshold, the drive system takes temperature control measures, such as reducing the PWM switching frequency or changing the SVPWM modulation control mode of the power device from a seven-segment SVPWM modulation mode to a five-segment SVPWM modulation mode, to reduce switching loss and reduce temperature, to intervene when the temperature is just starting to rise, to prevent the temperature from continuing to rise to a more dangerous level. The second temperature threshold is a higher warning line, indicating that the temperature of the power device has reached a level closer to its maximum safe operating temperature.

[0097] It should be noted that, like the first temperature threshold, the preset of the second temperature threshold needs to consider factors such as the characteristics of the power device, the maximum operating junction temperature, the response speed of the drive system to temperature changes, and the operation requirements of the drive motor. The value of the second temperature threshold can be set to be about 50℃ lower than the maximum operating junction temperature, that is, the value of the second temperature threshold can be set to be about 10℃ higher than the first temperature threshold. That is, assuming that the maximum operating junction temperature of the IGBT tube of the drive motor controller power device is 150℃, then the second temperature threshold can be 95℃, 97℃, 100℃, 103℃, 105℃, etc. However, the value of the second temperature threshold here is only used for illustration, and the application is not limited. In actual work, the setting of the second temperature threshold needs to be adjusted appropriately according to the actual situation such as the maximum operating junction temperature of the power device.

[0098] Specifically, if it is detected that the temperature of the power device is greater than the second temperature threshold, then controlling to turn off the active heating, to prevent the power device from overheating and possibly causing damage. The second temperature threshold is greater than the first temperature threshold, which realizes phased management of temperature risk and provides a layered response mechanism to ensure that the power device is properly protected at different temperature levels. It helps to optimize the performance and efficiency of the drive system while ensuring safety.

[0099] It should be noted that the use of the two PWM switching loss reduction control methods of reducing the PWM switching frequency of the power device to the target frequency and changing the SVPWM modulation control mode of the power device to the five-segment SVPWM modulation mode within a time period here is only used for illustration, and the application is not limited.

[0100] The heating control method of the vehicle provided by the embodiment of the present application manages the temperature by reducing the switching loss of the power device, and ensures the safety and efficiency of the system. In the method, when the temperature of the power device exceeds the first preset temperature, the PWM switching loss is controlled to be reduced, including reducing the PWM switching frequency of the power device to the target frequency, i.e. the lowest working frequency, in a preset time period, to reduce the switching loss and reduce the temperature, or changing the SVPWM modulation mode from seven segments to five segments, to reduce the switching times, so as to further reduce the temperature. Both of the two methods of reducing the PWM switching loss can each reduce the PWM switching times to reduce the temperature of the power device. Alternatively, when one of the methods of reducing the switching loss cannot temporarily reduce the temperature of the power device, the other method of reducing the switching loss can be further selected to further reduce the PWM switching times to reduce the temperature of the power device. If the temperature of the power device still cannot be reduced to the second temperature threshold at this time, the driving motor is controlled to be turned off to continuously actively heat. Through the above method, the relationship between temperature management and system performance is effectively balanced, the driving motor of the vehicle in a stationary state can also continuously actively heat, the service life of the power device is prolonged, and the stability and reliability of the vehicle driving system are ensured.

[0101] Figure 5 The structure diagram of the heating control device of the vehicle provided by the present application is shown in FIG. 1, and the heating control device 50 of the vehicle provided by the embodiment comprises: Figure 6

[0102] The first processing module 501 is configured to detect the temperature of the power device in real time during the active heating process.

[0103] The second processing module 502 is configured to control the switching loss of the power device to be reduced to reduce the temperature of the power device if the temperature is higher than the first preset temperature threshold.

[0104] The heating control device of the vehicle provided by the embodiment is used to execute the technical solutions in the foregoing method embodiments, and has similar implementation principles and technical effects, which will not be described here.

[0105] In a specific embodiment, the first processing module 501 is specifically configured to:

[0106] detect the temperature of each transistor in real time, and determine the highest temperature in the multiple temperatures as the temperature of the power device.

[0107] In a specific embodiment, the current SVPWM modulation control mode of the power device is a seven-segment SVPWM modulation mode, and the second processing module 502 is specifically configured to:

[0108] control the pulse width modulation (PWM) switching frequency of the power device to be reduced.​

[0109] and / or,

[0110] By changing the space vector pulse width modulation (SVPWM) control mode of the power device, the number of switching times in each switching cycle is reduced.

[0111] In one specific implementation, the second processing module 502 is specifically further configured to:

[0112] According to the preset time period, the PWM switching frequency of the power device is reduced to a target frequency within the time period, and the target frequency is the lowest working frequency of the PWM switching.

[0113] and / or,

[0114] The SVPWM modulation control mode of the power device is changed to a five-segment SVPWM modulation mode.

[0115] In one specific implementation, the second processing module 502 is specifically further configured to:

[0116] If it is detected that the temperature of the power device is still greater than the first temperature threshold, the SVPWM modulation control mode of the power device is changed from the seven-segment SVPWM modulation mode to the five-segment SVPWM modulation mode.

[0117] On the basis of the above-mentioned embodiments, the heating control device 50 of the vehicle further comprises:

[0118] The third processing module 503 is configured to control the active heating to be turned off if it is detected that the temperature of the power device is greater than a second temperature threshold, wherein the second temperature threshold is greater than the first temperature threshold, and the second temperature threshold is less than the highest working junction temperature of the power device.

[0119] The heating control device of the vehicle provided in any of the above-mentioned embodiments is used to execute the technical solutions in the above-mentioned method embodiments, and has similar implementation principles and technical effects, which will not be described here in detail.

[0120] Figure 6 A structural schematic diagram of a drive motor controller is provided in the present application. As shown in ​ The drive motor controller 60 provided in the present embodiment comprises at least one processor 601, a memory 602, and a power device 603. Optionally, the drive motor controller 60 further comprises a communication component 604. The processor 601, the memory 602, the power device 603, and the communication component 604 are connected through a bus 605.

[0121] In the process of specific implementation, the at least one processor 601 executes the computer execution instructions stored in the memory 602, so that the at least one processor 601 executes the above-mentioned method.

[0122] The specific implementation process of the processor 601 can refer to the method embodiments described above, which have similar implementation principles and technical effects, and thus will not be described here.

[0123] In the above embodiments, the processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor, etc. The steps of the disclosed method can be directly embodied as hardware processor execution, or executed by a combination of hardware and software modules in the processor.

[0124] The memory can include a random access memory (RAM), and can also include a non-volatile memory (NVM), such as at least one disk memory.

[0125] The bus can be an industry standard architecture (ISA) bus, a peripheral component (PCI) bus, an extended industry standard architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the bus in the drawings of the present application does not limit to only one bus or one type of bus.

[0126] The present application provides a vehicle, comprising a main body structure of the vehicle and the drive motor controller described above.

[0127] The present application also provides a computer readable storage medium, which stores computer execution instructions, and when the processor executes the computer execution instructions, the above method is realized.

[0128] The above-mentioned readable storage medium can be realized by any type of volatile or nonvolatile storage devices or a combination thereof, such as Static Random-Access Memory (SRAM), Electrically Erasable Programmable Read Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general or special purpose computer.

[0129] An exemplary readable storage medium is coupled to the processor, so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an Application Specific Integrated Circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in the device.

[0130] The division of units is only a logical functional division, and in actual implementation, there can be another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0131] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on multiple network units. According to actual needs, some or all of the units can be selected to achieve the purpose of the embodiment.

[0132] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0133] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the technical solutions that essentially contribute to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the method of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0134] It can be understood by those skilled in the art that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware. The aforementioned program can be stored in a computer readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, and various media that can store program codes.

[0135] Finally, it should be noted that: those skilled in the art will easily derive other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or conventional technical means in the art that are not disclosed in the present application, and is not limited to the precise structure described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is only limited by the appended claims.

Claims

1. A heating control method for a vehicle, characterized in that, include: During the active heating process of the drive motor when the vehicle is stationary, the temperature of the power devices is monitored in real time. If the temperature is higher than a preset first temperature threshold, the switching loss of the power device is reduced to lower the temperature of the power device, wherein the first temperature threshold is set according to the highest operating junction temperature of the power device. The control reduces the switching losses of the power device, including: According to a preset time period, within the time period, the pulse width modulation (PWM) switching frequency of the power device is reduced to a target frequency, where the target frequency is the minimum operating frequency of the PWM switch; and / or, By changing the space vector pulse width modulation (SVPWM) control mode of the power device, the seven-segment SVPWM modulation mode is changed to a five-segment SVPWM modulation mode, thereby reducing the number of switching cycles per switching cycle.

2. The method according to claim 1, characterized in that, The method further includes: If the temperature of the power device is still greater than the first temperature threshold, the SVPWM modulation control mode of the power device is changed from the seven-segment SVPWM modulation mode to the five-segment SVPWM modulation mode.

3. The method according to claim 2, characterized in that, The method further includes: If the temperature of the power device is detected to be greater than a second temperature threshold, active heating is turned off; wherein the second temperature threshold is greater than the first temperature threshold and less than the highest operating junction temperature of the power device.

4. The method according to any one of claims 1 to 3, characterized in that, The real-time detection of the power device's temperature includes: The temperature of each transistor is monitored in real time, and the highest temperature among multiple temperatures is determined as the temperature of the power device.

5. A vehicle heating control device, characterized in that, The vehicle heating control device is used to implement the vehicle heating control method according to any one of claims 1-4, the device comprising: The first processing module is used to detect the temperature of the power device in real time during the active heating process; The second processing module is used to control the reduction of the switching losses of the power device to lower the temperature of the power device if the temperature is higher than a preset first temperature threshold.

6. A drive motor controller, characterized in that, include: Memory, processor, and power devices; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-4.

7. A vehicle, characterized in that, include: The main structure of the vehicle and the drive motor controller as described in claim 6.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-4.

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