Heating control method and device of vehicle, vehicle and medium

Abstract

The embodiment of the invention provides a heating control method and device of a vehicle, the vehicle and a medium. The method comprises the steps that in the active heating process of a driving motor, a driving system detects the temperature of a power device of a driving motor controller in real time so as to ensure that the power device operates within a safe working range. And when it is detected that the temperature of the power device is higher than a preset first temperature threshold value, controlling the switching loss of the power device to reduce the calorific value of the power device. By means of the method, the driving motor can continuously and actively heat when the vehicle is in the static state, the heat management efficiency of the vehicle is improved, and the reliability of an electric vehicle driving system and the use experience of a user are improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a vehicle heating control method, device, vehicle and medium. Background Art

[0002] With the popularity of electric vehicles, the performance and endurance of vehicles under low temperature conditions have become the focus of users, and active heating methods for drive motors have emerged. However, when the vehicle is stationary, the active heating method for drive motors cannot completely balance the heat generated by the insulated-gate bipolar transistor (IGBT) of the power device, causing the maximum 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 a parking state and receives a heating request, and outputs multiple high-frequency PWM signals to the motor controller to control the motor controller to output high-frequency AC current to the stator of the drive motor, so that the stator and rotor of the drive motor generate heat in a stationary state, and conduct the heat to the device that initiates the heating request. When the vehicle is in a parking state, the method outputs a high-frequency PWM signal, which also means that the switching frequency of the power device is high, and the number of switching times is high, which will still lead to increased switching losses, thereby causing the temperature of the power device to rise and interrupt heating.

[0004] In summary, providing a control method that can achieve continuous active heating of the drive motor even when the vehicle is stationary is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present application provide a vehicle heating control method, device, vehicle and medium, which are used to achieve the technical effect of continuously and actively heating the drive motor even when the vehicle is in a stationary state, thereby ensuring the stability of the heating process.

[0006] In a first aspect, an embodiment of the present application provides a vehicle heating control method, comprising:

[0007] During active heating, 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 be reduced to reduce the temperature of the power device.

[0009] In a possible implementation manner, the controlling to reduce the switching loss of the power device includes:

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

[0011] and / or,

[0012] By changing the space vector pulse width modulation (SVPWM) control mode of the power device, the number of switches in each switching cycle is reduced.

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

[0014] According to a 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 minimum operating frequency of the PWM switch.

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

[0016] Accordingly, the method of reducing the number of switches in each switching cycle by changing the SVPWM modulation control mode of the power device includes:

[0017] The SVPWM modulation control mode of the power device is changed to a five-stage SVPWM modulation mode.

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

[0019] 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 a seven-segment SVPWM modulation mode to a five-segment SVPWM modulation mode.

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

[0021] If it is detected that the temperature of the power device is greater than a second temperature threshold, active heating is controlled to be turned off; 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.

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

[0023] The temperature of each transistor is detected in real time, and the highest temperature among multiple temperatures is determined as the temperature of the power device.

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

[0025] A first processing module is used to detect the temperature of the power device in real time during the active heating process;

[0026] The second processing module is used for controlling to reduce the switching loss of the power device so as to reduce the temperature of the power device if the temperature is higher than a preset first temperature threshold.

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

[0028] Memory, processors and power devices;

[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 above first aspect and / or various possible implementations 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 a drive motor controller as described in the third aspect.

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

[0033] The vehicle heating control method, device, vehicle and medium provided by the embodiments of the present application, in the process of active heating of the drive motor, the drive system detects the temperature of the power device of the drive motor controller in real time to ensure that it operates within a safe operating range. When it is detected 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 reduce the heat generated by the power device. Through the above method, not only can the power device be protected from overheating damage, but also continuous active heating of the drive motor can be achieved when the vehicle is static, thereby achieving more efficient thermal management. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this 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 schematic diagram of a vehicle heating control method provided in this application Figure 1 ;

[0036] Figure 2 A specific implementation method of a vehicle heating control method provided in this application Figure 1 ;

[0037] Figure 3 A schematic diagram of a vehicle heating control method provided in this application Figure 2 ;

[0038] FIG4 (a) is a specific implementation of a vehicle heating control method provided by the present application Figure 2 ;

[0039] FIG4( b ) is a specific implementation of a vehicle heating control method provided by the present application. Figure 3 ;

[0040] Figure 5 A schematic structural diagram of a vehicle heating control device provided in the present application;

[0041] Figure 6 A schematic diagram of the structure of a drive motor controller provided in this application.

[0042] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0043] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0044] First, the terms involved in this application are explained:

[0045] Pulse Width Modulation (PWM): It is an analog control method that changes the conduction time of the transistor according to the change of the corresponding load, thereby changing the output of the switching regulated power supply. The transistor (commonly used IGBT, Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) and other fully controlled devices) works in a switching state. 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 cycle) to adjust the motor voltage, speed control or drive motor torque can be performed.

[0046] Space Vector Pulse Width Modulation (SVPWM): refers to the ideal flux circle of the stator of a three-phase symmetrical motor when powered by a three-phase symmetrical sine wave voltage as a reference standard, and the appropriate switching of different switching modes of the three-phase inverter to form a PWM wave, and use the actual flux vector formed to track its accurate flux circle. This method regards the inverter system and the asynchronous motor as a whole, and controls the operation of the inverter according to how to generate a circular rotating magnetic field.

[0047] Junction Temperature: refers to the actual operating temperature of the semiconductor junction in electronic equipment, that is, the PN junction. The interior of a semiconductor device is composed of multiple PN junctions.

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

[0049] The application background of this application is then explained as follows:

[0050] When there is a need for heating in the thermal management system of pure electric vehicles, the traditional heating method uses an electric heater that uses the characteristic that the resistance of the positive temperature coefficient (PTC) thermistor material increases with the increase of temperature. The PTC thermistor material has a lower resistance at low temperatures and can quickly pass current to generate heat. When the temperature rises to a certain level, the resistance will increase rapidly, thereby limiting the passage of current and achieving the effect of self-regulating the temperature. The PTC electric heater draws electricity from the vehicle's battery to generate heat. However, the battery capacity of electric vehicles is limited, and any additional power consumption will reduce the amount of electricity available to drive the vehicle, affecting the vehicle's endurance.

[0051] With the popularity of electric vehicles, the performance and endurance of vehicles under low temperature conditions have become the focus of users, and active heating methods for drive motors have emerged. This method uses the heat generated by the drive motor in a stationary state and transfers it to the battery pack and the cabin through the coolant, thereby increasing the operating temperature of the battery and the comfort of the vehicle. Specifically, the electric vehicle drive system obtains the heating power of the power device according to the active heating command, determines the positive and negative symmetrical AC heating current, and applies it to the direct axis of the drive system motor to achieve balanced heating of the power devices of the electric vehicle drive system. However, when the vehicle is stationary, the active heating method of the drive motor cannot completely balance the heating of the IGBT tube of the power device, resulting in the maximum temperature of the power device possibly exceeding the safety threshold and interrupting 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 multiple high-frequency PWM signals to the motor controller to control the motor controller to output high-frequency AC current to the stator of the drive motor, so that the stator and rotor of the drive motor generate heat in a stationary state, and conduct the heat to the device that initiates the heating request. When the vehicle is in the parking state, the method outputs a high-frequency PWM signal, which also means that the switching frequency of the power device is high, and the number of switching times is high, which will still lead to increased switching losses, thereby causing the temperature of the power device to rise and interrupt heating.

[0053] In summary, it is a technical problem that needs to be solved urgently to effectively solve the problem that active heating of the drive motor cannot completely balance the heat generated by the IGBT tube of the power module when the vehicle is stationary, and to provide a control method for achieving continuous active heating of the drive motor when the vehicle is stationary.

[0054] Based on the above technical problems, the inventors found that the main causes of heating of power devices include conduction loss heating and switching loss heating during the process of studying the continuous active heating control method of the vehicle's drive motor. The heating power of the power device can be directly obtained according to the active heating demand of the drive motor, which directly determines the size of the control current, that is, the size of the conduction loss. Therefore, the heating of the power device can be reduced by reducing the switching loss when the power device is working to solve the above technical problems. Based on this, the present application provides a vehicle heating control method, device, vehicle and medium, so as to achieve continuous active heating of the drive motor when the vehicle is in a stationary state, ensure the stability of the heating process, and achieve a more efficient technical effect of thermal management.

[0055] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are 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 repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0056] Figure 1 A schematic diagram of a vehicle heating control method provided in this application Figure 1 , Figure 2 A specific implementation method of a vehicle heating control method provided in this application Figure 1 ,like Figure 1 As shown, the method includes:

[0057] S101. During active heating, the temperature of the power device is detected in real time.

[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. These six IGBT tubes are configured into a three-phase bridge circuit, each phase consists of two IGBT tubes, one connected to the positive DC bus, that is, the upper bridge arm; one connected to the negative DC bus, that is, the lower bridge arm. Specifically, the IGBT tube of the upper bridge arm of the U phase controls the positive current of the U phase; the IGBT tube of the lower bridge arm of the U phase controls the negative current of the U phase; the IGBT tube of the upper bridge arm of the V phase controls the positive current of the V phase; the IGBT tube of the lower bridge arm of the V phase controls the negative current of the V phase; the IGBT tube of the upper bridge arm of the W phase controls the positive current of the W phase; the IGBT tube of the lower bridge arm of the W phase controls the negative current of the W phase. The IGBT tubes work in coordination to generate the required three-phase AC current to drive the motor.

[0059] It should be noted that the IGBT tube in this application is only used for illustration. In actual applications, it may be a MOS tube or other types. This application does not specifically limit the specific form and type of the physical equipment 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 AC heating current to be applied to 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 quadrature axis current of the drive motor needs to be set to 0, and the motor winding is heated by adjusting the direct axis current, so that the power devices of the drive motor controller of the electric vehicle drive system are evenly heated.

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

[0062] S102 : If the temperature is higher than a preset first temperature threshold, control the reduction of the switching loss of the power device to reduce the temperature of the power device.

[0063] In this step, the three-phase AC current of the driving motor generates heat when passing through the power device of the motor controller, causing the junction temperature to rise. The maximum operating junction temperature is used to indicate the maximum temperature that the PN junction inside the power device can withstand under normal working conditions. Exceeding this temperature may cause the performance of 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, presetting the first temperature threshold helps the junction temperature of the power device to take appropriate adjustment and protection measures before reaching the maximum operating 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 comprehensively consider the characteristics of the power device, the maximum operating junction temperature, the response speed of the electric vehicle drive system to temperature changes, and the operating requirements of the drive motor. If the first temperature threshold is too high, it means that the electric vehicle drive system is not sensitive enough to temperature changes, and may not be able to effectively reduce the temperature of the power device in a timely manner, thereby threatening the safety and reliability of the entire electric vehicle drive system. On the contrary, if the first temperature threshold is too low, it 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 value of the first temperature threshold 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 drive motor controller power device is 150°C, the first preset temperature threshold 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 are only used for illustration, and this application does not make specific restrictions. In actual work, the setting of the first temperature threshold needs to be appropriately adjusted according to the actual situation such as the maximum operating junction temperature of the power device, so as to ensure that protective measures can be taken in a timely and effective manner before the temperature of the power device reaches a dangerous level, and to avoid unnecessary interference and impact on the system caused by overly frequent protection actions.

[0066] When the vehicle is stationary, the method of passing the AC heating current through the direct shaft of the motor of the electric vehicle drive system to heat the power device of the drive motor controller will cause uneven heating of the power device of the drive motor controller. In this case, the power device of the drive motor controller is likely to reach the highest temperature protection point and cause shutdown, affecting the continuous active heating of the drive motor. The main causes of heating of the power device include conduction loss heating and switching loss heating.

[0067] Conduction loss usually refers to the energy loss caused by the resistance of the device itself during the conduction period when the power device is in the on state, that is, when the current passes through the device, a certain power loss is generated due to the on-resistance of the device (usually called on-state resistance or on-voltage drop). The magnitude of the conduction loss is proportional to the square of the current, because the power loss can be expressed as the square of the current multiplied by the on-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 switching. Specifically, turn-on loss refers to the energy loss caused by the overlap of voltage and current when the power device switches from the off state to the on state, the voltage gradually decreases to near zero, while the current rises rapidly to the load current; turn-off loss refers to the energy loss caused by the overlap of voltage and current when the power device switches from the on state to the off state, the current gradually decreases to zero, but the voltage rises rapidly to the power supply voltage. Figure 2 As shown, the turn-on loss and turn-off loss correspond to the area where the voltage and current curves intersect, that is, the time period when the voltage and current exist at the same time, and the conduction loss corresponds to the continuous voltage drop area when the current passes through the power device.

[0069] The heating power of the power device can be directly obtained according to the active heating demand of the drive motor, which directly determines the size of the control current, that is, the size of the conduction loss. Therefore, the heating of the power device can be reduced by reducing the switching loss when the power device is working, and the heating of the power device can be reduced so that the drive motor can continue to be actively heated. The size of the switching loss is related to the switching frequency, the switching speed of the power device, and the waveform 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 drive motor controller is higher than a preset first temperature threshold, the switching loss of the power device is controlled to be reduced. In this solution, the method of controlling the switching loss of the power device includes: controlling the PWM switching frequency of the power device to be reduced and / or reducing the number of switches in each switching cycle by changing the SVPWM modulation control method of the power device, so as to reduce the temperature and effectively reduce the energy loss of the power device during the switching process, thereby reducing the working junction temperature of the power device, improving the stability and reliability of the system, extending the service life of the power device, and optimizing the operating efficiency of the drive motor.

[0071] The vehicle heating control method provided by the embodiment of the present application detects the temperature of the power device in real time during the continuous active heating process of the drive motor to ensure that it operates within a safe working range. Specifically, in response to the active heating instruction of the drive motor, the drive system obtains the active heating request power according to the heating instruction, and determines the size of the AC heating current to be applied, and passes the AC heating current through the direct shaft of the motor of the tram drive system to make the drive motor controller power device of the tram drive system evenly heated. However, due to the uneven distribution of the three-phase AC current when the vehicle is stationary, it may cause uneven heating of the IGBT tube. When the drive system detects that the temperature of the power device is higher than the preset first temperature threshold, it controls to reduce the switching loss of the power device to reduce the temperature of the power device and avoid local temperature being too high and damaging the device. Through the above method, the continuous active heating function of the drive motor when the vehicle is in a stationary state is realized, the stability and reliability of the drive system are improved, and the service life of the power device is extended. The drive system can maintain high operating efficiency and stability while meeting the active heating requirements of the drive motor.

[0072] Figure 3 A schematic diagram of a vehicle heating control method provided in this application Figure 2 FIG4 (a) is a specific implementation of a vehicle heating control method provided by the present application. Figure 2 FIG4( b ) is a specific implementation of a vehicle heating control method provided by the present application. Figure 3 ,like Figure 3 As shown, in this embodiment Figure 1Based on the embodiment, a vehicle heating control method is described in detail. The control to reduce the switching loss of the power device in the method includes:

[0073] The first case: according to a 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 minimum operating frequency of the PWM switch.

[0074] In this case, the PWM switching frequency refers to the number of times the IGBT, the power device driving the motor controller, switches in a unit time. A higher switching frequency can usually achieve more precise control, but it will also increase switching losses. The minimum operating frequency of the PWM switch refers to the minimum switching frequency at which the power device can work stably without affecting its function and performance and maintaining normal working conditions. If the PWM switching frequency is lower than the minimum operating frequency, the power device may not work properly or its performance may be greatly reduced. Therefore, reducing the PWM switching frequency to the minimum operating frequency can reduce switching losses and thus reduce the temperature of the device.

[0075] Specifically, in the process of driving the motor to achieve continuous active heating, it is assumed that the PWM switching frequency of the power device of the driving motor controller is , the driving motor continues active heating time is Under normal circumstances, the current SVPWM modulation control mode of the drive motor controller power device is a seven-segment SVPWM modulation mode. Therefore, in the process of continuous active heating of the drive motor, the heating time is The number of switching times of the power device of the drive motor controller is 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. , target frequency is the minimum operating frequency of the PWM switch. At this time, the heating time The number of switching times of the power device of the drive motor controller is Obviously, The method of reducing the PWM switching frequency of the power device to the target frequency within a time period reduces the PWM switching frequency, thereby achieving the purpose of controlling and reducing the switching loss of the power device to reduce the temperature of the power device.

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

[0077] In this case, the main idea of ​​SVPWM is to form a three-phase PWM wave output by switching different switching modes of the three-phase inverter, and obtain the target stator current by controlling the phase voltage. In the SVPWM control algorithm, according to the number of switching times of the PWM signal in one cycle, it can be divided into seven-segment SVPWM and five-segment SVPWM. The seven-segment SVPWM is a traditional SVPWM implementation method. In each switching cycle, the output voltage of the three-phase motor is decomposed into seven vectors, namely, the positive maximum vector, the positive middle vector, the positive minimum vector, the negative minimum vector, the negative middle vector, the negative maximum vector and the zero vector. The seven-segment SVPWM achieves a smoother voltage output by applying the zero vector at the beginning and end of each cycle and alternately applying the effective vector in the middle. As shown in Figure 4 (a), the seven-segment SVPWM wave is symmetrical and has a small harmonic content. In each switching cycle, There are 6 switching jumps in the five-segment SVPWM. The five-segment SVPWM decomposes the output voltage of the three-phase motor into five vectors, namely, the positive maximum vector, the positive medium vector, the zero vector, the negative medium vector and the negative maximum vector. The effective vector is applied at the beginning and end of each cycle, and the zero vector is inserted in the middle. The five-segment SVPWM and the seven-segment SVPWM maintain the same sequence arrangement of each phase switch in each sector, as shown in Figure 4 (b). The five-segment SVPWM has 4 switching jumps in each switching cycle.

[0078] Specifically, in the process of driving the motor to achieve continuous active heating, it is assumed that the PWM switching frequency of the power device of the driving motor controller is , the driving motor continues active heating time is Under normal circumstances, the current SVPWM modulation control mode of the drive motor controller power device is a seven-segment SVPWM modulation mode. Therefore, in the process of continuous active heating of the drive motor, the heating time is The number of switching times of the power device of the drive motor controller is If the temperature of the power device is higher than the preset first temperature threshold, the SVPWM modulation control mode of the power device is changed to a five-stage SVPWM modulation mode. At this time, the heating time The number of switching times of the power device of the drive motor controller is Obviously, The method of changing the SVPWM modulation control mode of the power device to a five-stage SVPWM modulation mode reduces the PWM switching frequency, achieving 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:

[0080] S301 . In a process of realizing active heating, in response to an active heating instruction of the driving motor, obtaining an active heating request power of the driving motor according to the heating instruction.

[0081] S302: further determine the magnitude of the AC heating current that needs to be applied to the direct shaft of the drive motor.

[0082] In this step, what needs to be applied to the direct axis of the driving motor is a positive and negative symmetrical AC heating current, and its waveform is symmetrical in the positive half cycle and the negative half cycle, that is, the average value of the positive and negative symmetrical AC heating current in a complete cycle is zero, but the same thermal effect will be produced in each half cycle. The amplitudes of the positive half cycle and the negative half cycle of the positive and negative symmetrical AC heating current are equal and opposite in direction, ensuring that the energy received by the load in each cycle is constant. Since the heat generated by the current passing 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 and negative symmetrical AC heating current can use a standard AC power supply without the need for additional rectification or filtering equipment, thereby reducing costs.

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

[0084] In this step, the determined positive and negative symmetrical AC heating current is applied to the direct axis of the drive motor, and the quadrature axis current of the drive motor is controlled to be zero. At this time, the electronic winding generates heat, and the power device of the drive motor controller also generates a certain amount of heat.

[0085] S304: Determine in real time whether the temperature of the power device is greater than a first temperature threshold.

[0086] S305 : If it is detected that the temperature of the power device is higher than a preset first temperature threshold, control the reduction of the switching loss of the power device to reduce the temperature of the power device.

[0087] In this step, when the vehicle is in a stationary state, on the one hand, the three-phase AC current of the drive motor is unevenly distributed, resulting in different currents passing through the IGBT tube and uneven heating of the IGBT tube; on the other hand, the drive motor itself has good thermal conductivity, and the power device of the drive motor controller heats up quickly. The method of passing the AC heating current through the direct shaft of the motor of the tram drive system to heat the power device of the drive motor controller cannot achieve balanced heating of the power device. Therefore, relevant measures need to be taken to reduce the temperature of the power device to prevent the uneven heating of the power device of the drive motor controller, resulting in a rapid rise in local temperature and shutdown. On the contrary, if the temperature of the power device is not detected to be higher than the preset first temperature threshold, it indicates that the vehicle is in a non-stationary state, the IGBT tube of the power device of the drive motor controller heats up evenly, or the vehicle is in a stationary state. Although the IGBT tube of the power device of the drive motor controller heats up unevenly, its highest temperature does not reach the first temperature threshold. At this time, the drive motor can continue to be actively heated.

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

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

[0090] S3052: Determine 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 second case above, 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. The number of switching times of the power device of the drive motor controller is Obviously, ; , achieving the purpose of further reducing the PWM switching frequency, further reducing the switching loss of power devices, and further reducing the temperature of power devices.

[0094] S306: Determine whether the temperature of the power device is greater than a second temperature threshold.

[0095] S307. If it is detected that the temperature of the power device is greater than a second temperature threshold, active heating is controlled to be turned off; wherein the second temperature threshold is greater than the first temperature threshold, and the second temperature threshold is less than the highest operating junction temperature of the power device.

[0096] In this step, in order 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 damage under extreme conditions. The first temperature threshold is a preliminary warning line used to detect whether the temperature of the power device begins 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 losses and lower the temperature, and intervenes when the temperature just begins 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 second temperature threshold needs to comprehensively consider the characteristics of the power device, the maximum operating junction temperature, the response speed of the electric vehicle drive system to temperature changes, and the operating requirements of the drive motor. The value of the second temperature threshold can be set to be about 50°C lower than the maximum operating junction temperature, that is, the value of the second temperature threshold can be set to be about 10°C 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°C, then the second temperature threshold can be 95°C, 97°C, 100°C, 103°C, 105°C, etc. However, the second temperature threshold value here is only used for illustration, and this application does not make specific limitations. In actual work, the setting of the second temperature threshold needs to be appropriately adjusted according to the actual situation such as the maximum operating junction temperature of the power device.

[0098] Specifically, if the temperature of the power device is detected to be greater than the second temperature threshold, active heating is controlled to be turned off to prevent the power device from overheating and possibly causing damage. The second temperature threshold is greater than the first temperature threshold to achieve staged management of temperature risks and provide a layered response mechanism to ensure that power devices are properly protected at different temperature levels. This 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 control methods for reducing PWM switching losses, namely, reducing the PWM switching frequency of the power device to the target frequency within a time period and changing the SVPWM modulation control method of the power device to a five-stage SVPWM modulation method, is only for illustration and is not specifically limited in this application.

[0100] The vehicle heating control method provided by the embodiment of the present application manages the temperature by reducing the switching loss of the power device to ensure the safety and efficiency of the system. In this 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, that is, the minimum operating frequency, within a preset time period to reduce the switching loss and reduce the temperature or changing the SVPWM modulation mode from seven-segment to five-segment to reduce the number of switches, thereby further reducing the temperature. Both methods of reducing PWM switching loss can each achieve the reduction of the number of PWM switches to reduce the temperature of the power device. Optionally, when one of the methods of reducing switching loss cannot temporarily reduce the temperature of the power device, another method of reducing switching loss can be further selected to further reduce the number of PWM switches to reduce the temperature of the power device. If the temperature of the power device cannot be reduced to the second temperature threshold at this time, the drive motor is controlled to be turned off for continuous active heating. Through the above method, the relationship between temperature management and system performance is effectively balanced, and the drive motor can be continuously and actively heated when the vehicle is stationary, which prolongs the service life of the power device and ensures the stability and reliability of the vehicle drive system.

[0101] Figure 5 A schematic diagram of the structure of a vehicle heating control device provided in this application, such as Figure 5 As shown, the vehicle heating control device 50 provided in this embodiment includes:

[0102] The first processing module 501 is used 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 reduction of the switching loss of the power device to reduce the temperature of the power device if the temperature is higher than a preset first temperature threshold.

[0104] The vehicle heating control device provided in this embodiment is used to execute the technical solution in the aforementioned method embodiment, and its implementation principle and technical effect are similar and will not be repeated here.

[0105] In a specific implementation, the first processing module 501 is specifically used for:

[0106] The temperature of each transistor is detected in real time, and the highest temperature among multiple temperatures is determined as the temperature of the power device.

[0107] In a specific implementation, 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 used for:

[0108] Control and reduce the pulse width modulation (PWM) switching frequency of power devices;

[0109] and / or,

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

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

[0112] According to a 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 minimum operating frequency of the PWM switch.

[0113] and / or,

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

[0115] In a specific implementation, the second processing module 502 is 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] Based on the above embodiment, the heating control device 50 of the vehicle further includes:

[0118] The third processing module 503 is used to control the shutdown of active heating 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 maximum operating junction temperature of the power device.

[0119] The vehicle heating control device provided in any of the above embodiments is used to execute the technical solution in the above method embodiments, and its implementation principle and technical effect are similar and will not be repeated here.

[0120] Figure 6 This is a schematic diagram of the structure of a drive motor controller provided in this application. Figure 6 As shown, the drive motor controller 60 provided in this embodiment includes: at least one processor 601, a memory 602 and a power device 603. Optionally, the drive motor controller 60 also includes a communication component 604. The processor 601, the memory 602, the power device 603 and the communication component 604 are connected via a bus 605.

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

[0122] The specific implementation process of the processor 601 can be found in the above method embodiment, and its implementation principle and technical effect are similar, so this embodiment will not be repeated here.

[0123] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc. The steps of the method disclosed in the invention may be directly embodied as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0124] The memory may include high-speed memory (Random Access Memory, RAM), and may also include non-volatile memory (NVM), such as at least one disk storage.

[0125] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or 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 this application is not limited to only one bus or one type of bus.

[0126] The present application provides a vehicle, including a main structure of the vehicle and the above-mentioned drive motor controller.

[0127] The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the above method is implemented.

[0128] The above-mentioned readable storage medium can be implemented by any type of volatile or non-volatile storage device 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 a 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 a component 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 in the device as discrete components.

[0130] The division of units is only a logical function division, and there may be other divisions in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

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

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

[0133] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory ROM, random access memory (Random Access Memory, RAM), disk or optical disk, etc., which can store program codes.

[0134] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. 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, disk or optical disk and other media that can store program codes.

[0135] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A vehicle heating control method, characterized in that: include: During active heating, the temperature of the power device is detected in real time; If the temperature is higher than a preset first temperature threshold, the switching loss of the power device is controlled to be reduced to reduce the temperature of the power device.

2. The method according to claim 1, characterized in that: The controlling reduces the switching loss of the power device, including: Controlling to reduce the pulse width modulation (PWM) switching frequency of the power device; and / or, By changing the space vector pulse width modulation (SVPWM) control mode of the power device, the number of switches in each switching cycle is reduced.

3. The method according to claim 2, characterized in that The controlling to reduce the PWM switching frequency of the power device includes: According to a 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 minimum operating frequency of the PWM switch.

4. The method according to claim 2, characterized in that: The current SVPWM modulation control mode of the power device is a seven-segment SVPWM modulation mode; Accordingly, the method of reducing the number of switches in each switching cycle by changing the SVPWM modulation control mode of the power device includes: The SVPWM modulation control mode of the power device is changed to a five-stage SVPWM modulation mode.

5. The method according to claim 4, characterized in that The method further comprises: 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 a seven-segment SVPWM modulation mode to a five-segment SVPWM modulation mode.

6. The method according to claim 5, characterized in that The method further comprises: If it is detected that the temperature of the power device is greater than a second temperature threshold, active heating is controlled to be turned off; 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.

7. The method according to any one of claims 1 to 6, characterized in that: The real-time detection of the temperature of the power device comprises: The temperature of each transistor is detected in real time, and the highest temperature among multiple temperatures is determined as the temperature of the power device.

8. A heating control device for a vehicle, characterized in that: include: A 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 for controlling to reduce the switching loss of the power device so as to reduce the temperature of the power device if the temperature is higher than a preset first temperature threshold.

9. A drive motor controller, characterized in that: include: Memory, processors and power devices; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory, so that the processor performs the method according to any one of claims 1 to 7.

10. A vehicle, characterized in that: include: The main structure of the vehicle and the drive motor controller as claimed in claim 9.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 7 when executed by a processor.

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