Motor control method and device in trailer mode and vehicle

Abstract

This application provides a motor control method, device, and vehicle in trailer mode, relating to the field of vehicle control technology. The method includes: responding to a trailer command sent by the vehicle controller, performing a vehicle status self-check, and acquiring the vehicle's trailer status, which includes voltage status and controller enable status; determining the vehicle's trailer mode based on the trailer status; and controlling the speed of each switch in the motor controller and the motor according to the trailer mode to achieve trailer operation. By employing different control strategies for the motor under different vehicle states, excessive back EMF of the motor can be effectively suppressed, the trailer speed and allowable range can be maximized, the braking torque during trailer operation can be reduced, and the safety of electronic control components and passengers can be maximized.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, specifically to a motor control method, device, and vehicle in trailer mode. Background Technology

[0002] New energy pure electric direct-drive vehicles have no gearbox or physical neutral position; the motor output shaft and wheels are always physically connected. Therefore, in the event of an accident or other situations requiring towing, if the vehicle's drive wheels touch the ground and the drive shaft is not disconnected or the three-phase connection between the motor and controller is not severed, the back electromotive force generated by the permanent magnet synchronous motor may damage electronic control components and cause irreversible damage as the towed vehicle's motor speed increases, potentially threatening personal safety. Summary of the Invention

[0003] In view of this, this application provides a motor control method, device and vehicle in trailer mode. By adopting different control strategies for the motor in different vehicle states, the excessive back EMF of the motor can be effectively suppressed, the trailer speed and allowable range can be widened to the maximum extent, the braking torque during trailer operation can be reduced, and the safety of electronic control components and passengers can be protected to the greatest extent.

[0004] To achieve the above objectives, this application provides the following technical solution: a motor control method in trailer mode, comprising: responding to a trailer command sent by a vehicle controller, performing a vehicle status self-check, and acquiring the trailer status of the vehicle, wherein the trailer status includes voltage status and controller enable status; determining the trailer mode of the vehicle based on the trailer status; and controlling the speed of each switch in the motor controller and the motor according to the trailer mode to achieve trailer operation.

[0005] In one embodiment of this application, determining the towing mode of the vehicle based on the towing status includes: if the voltage state is high voltage and the controller is enabled, then controlling the vehicle to tow using a first towing mode, wherein the first towing mode refers to towing control across the entire speed range; if the voltage state is high voltage and the controller is not enabled, then controlling the vehicle to tow using a second towing mode, wherein the second towing mode refers to controlling the motor controller based on the speed; if the voltage state is low voltage and the controller is not enabled, then controlling the vehicle to tow using a third towing mode, wherein the third towing mode refers to towing control with a limited speed.

[0006] In one embodiment of this application, the step of controlling the speed of each switch in the motor controller and the motor according to the trailer mode to achieve trailer towing includes: if the first trailer mode is used to control the vehicle to trailer, then controlling each switch in the motor controller to turn on, and simultaneously performing zero torque control on the motor; controlling free towing within the full speed range; and feeding back the maximum allowable trailer speed to the vehicle controller as the peak speed of the motor.

[0007] In one embodiment of this application, the control of the trailer to move freely within the full speed range further includes: obtaining the current speed of the motor; if the current speed is greater than a first reference speed, then looking up a preset current mapping table based on the zero torque and the current speed to obtain a field weakening current corresponding to the zero torque and the current speed; and controlling the motor controller to output the field weakening current.

[0008] In one embodiment of this application, the step of controlling the switching transistors in the motor controller and the speed of the motor according to the trailer mode to achieve trailer towing includes: if the second trailer mode is used to control the vehicle to trailer, then obtaining the current speed of the motor; controlling the on / off state of each switching transistor in the motor controller according to the current speed to achieve trailer towing; and feeding back the maximum allowable trailer speed as the rated speed of the motor to the vehicle controller.

[0009] In one embodiment of this application, the step of controlling the on / off state of each switch in the motor controller according to the current speed to realize the trailer includes: if the current speed is less than or equal to a second reference speed, then controlling each switch in the motor controller to turn off; if the current speed is greater than the second reference speed, then performing active short-circuit control on the motor controller, and simultaneously outputting a target temperature to control the cooling system to dissipate heat based on the target temperature, wherein the target temperature is the greater of the actual motor temperature and a preset temperature substitution value.

[0010] In one embodiment of this application, the step of controlling the speed of each switch in the motor controller and the motor according to the trailer mode to achieve trailer towing includes: if the third trailer mode is used to control the vehicle to trailer, then controlling each switch in the motor controller to turn off; and feeding back the maximum allowable trailer speed to the vehicle controller as the rated speed of the motor.

[0011] In one embodiment of this application, the step of performing a vehicle status self-check and obtaining the vehicle's towing status includes: performing a vehicle fault self-check; if there is a fault that prevents towing, controlling the exit from towing mode and outputting whether towing is enabled; self-checking whether the current voltage is high or low and obtaining the voltage status; detecting whether a controller enable command sent by the vehicle controller is received and determining the controller enable status.

[0012] As a second aspect of this application, this application also provides a motor control device in trailer mode, comprising: a status self-test module, used to respond to a trailer command sent by the vehicle controller, perform a vehicle status self-test, and obtain the trailer status of the vehicle, the trailer status including voltage status and controller enable status; a mode determination module, used to determine the trailer mode of the vehicle according to the trailer status; and a motor control module, used to control the switching transistors in the motor controller and the speed of the motor according to the trailer mode to realize trailer towing.

[0013] As a third aspect of this application, this application also provides a vehicle, including: the motor control device in trailer mode described above.

[0014] This application provides a motor control method in trailer mode. By responding to a trailer command sent by the vehicle controller, the method performs a vehicle status self-check and obtains the vehicle's trailer status, including voltage status and controller enable status. Based on the trailer status, the method determines the vehicle's trailer mode. According to the trailer mode, it controls the switching transistors in the motor controller and the motor speed to achieve trailer operation. By employing different control strategies for the motor under different vehicle states, it can effectively suppress excessive back EMF of the motor, maximize the trailer speed and allowable range, reduce braking torque during trailer operation, and maximize the protection of electronic control components and the personal safety of drivers and passengers. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 This is a flowchart illustrating a motor control method in trailer mode provided in an embodiment of this application.

[0017] Figure 2 This is a schematic diagram of the speed and torque curves under the active short-circuit and full shut-off strategies provided in the embodiments of this application.

[0018] Figure 3 This is an example diagram of a motor control method in trailer mode provided in an embodiment of this application.

[0019] Figure 4 This is a schematic diagram of the motor control device in trailer mode provided in an embodiment of this application. Detailed Implementation

[0020] This application provides a motor control method, device, and vehicle in trailer mode. By adopting different control strategies for the motor under different vehicle conditions, the excessive back EMF of the motor can be effectively suppressed, the trailer speed and allowable range can be widened to the maximum extent, the braking torque during trailer operation can be reduced, and the safety of electronic control components and passengers can be protected to the greatest extent.

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

[0022] New energy pure electric direct-drive vehicles lack a gearbox and physical neutral; the motor output shaft and wheels are always physically connected. Therefore, in the event of an accident or other towing scenario, if the drive wheels touch the ground and the drive shaft is not disconnected or the three-phase connection between the motor and controller is not severed, the back electromotive force generated by the permanent magnet synchronous motor as the towed vehicle's motor speed increases may damage the motor controller components, causing irreversible damage and potentially threatening personal safety.

[0023] The technical solution of this application embodiment is applicable to the application scenario of towing new energy vehicles. Figure 1 The diagram shown is a flowchart illustrating a motor control method in trailer mode according to an embodiment of this application, applied to a motor control unit (MCU) connected to a motor controller. Figure 1 As shown, motor control in trailer mode includes: Step S11: In response to the towing command sent by the vehicle controller, perform a vehicle status self-check and obtain the vehicle's towing status, which includes the voltage status and the controller enable status.

[0024] The vehicle control unit (VCU) can send towing commands to the motor control unit via hardwire or message; the towing commands include the vehicle's high and low voltage status, towing enable, etc.

[0025] After receiving a towing command from the vehicle controller, the motor control unit responds to the command and performs a vehicle status self-check to obtain the vehicle's towing status. The towing status includes voltage status and controller enable status. The voltage status is the vehicle's high voltage status, which is the bus voltage status connected to the input terminal of the motor controller. The controller enable status refers to whether a motor controller enable command signal from the vehicle controller has been received. If a motor controller enable command signal is received, it indicates that the controller is enabled; otherwise, it indicates that the controller is not enabled.

[0026] Step S12: Determine the vehicle's towing mode based on the towing status.

[0027] Different towing modes for a vehicle can be determined based on the voltage status and the controller's enable state. For example, if the bus voltage is high, the back EMF generated by the motor during towing is unlikely to exceed the bus voltage. If the bus voltage is low, the back EMF generated by the motor during towing can easily exceed the bus voltage. If the controller is enabled, real-time closed-loop regulation of the motor speed and other parameters can be achieved through control of the motor controller. Based on this, different towing modes can be defined according to the voltage status and controller enable state to effectively suppress excessive back EMF from the motor and maximize the range and allowable speed of the towing vehicle.

[0028] Step S13: Control the speed of each switch in the motor controller and the motor according to the trailer mode to realize trailer operation.

[0029] Different motor control strategies are adopted for different trailer modes, namely, different control of each switch in the motor controller, and matching the motor speed with the corresponding trailer mode, so as to maximize the range of trailer speed and reduce the braking torque during trailer operation.

[0030] This embodiment of the application performs a vehicle status self-check in response to a towing command sent by the vehicle controller and obtains the vehicle's towing status, which includes voltage status and controller enable status. Based on the towing status, the vehicle's towing mode is determined. Based on the towing mode, the speed of each switch in the motor controller and the motor are controlled to achieve towing. By adopting different control strategies for the motor under different vehicle states, excessive back EMF of the motor can be effectively suppressed, the towing speed and allowable range can be widened to the maximum extent, the braking torque during towing can be reduced, and the safety of electronic control components and passengers can be protected to the greatest extent.

[0031] In this embodiment, after receiving a towing command from the vehicle controller, the system responds to the command to tow the vehicle. However, a self-check of the vehicle's status is required before towing to employ different control strategies under different vehicle conditions, effectively suppressing excessive back EMF of the motor during towing. Therefore, the self-check of the vehicle's status and acquisition of its towing status includes: performing a vehicle fault self-check; if a fault prevents towing, the system exits the towing mode and outputs "no" for towing enable; checking whether the current voltage is high or low, and acquiring the voltage status; and detecting whether a controller enable command has been received from the vehicle controller, determining the controller enable status. Specifically, after receiving and responding to the towing command, the motor control unit performs a fault self-check; if a serious fault prevents towing, it exits the towing mode, and the external towing enable is set to 0. The motor control unit performs high / low voltage status self-checks and controller enable self-checks, i.e., checking whether the bus voltage is currently high or low. It also checks whether an enable command has been received from the vehicle controller (VCU).

[0032] After completing the trailer status self-check, the trailer mode can be classified according to the trailer status. Optionally, determining the vehicle's trailer mode based on the trailer status includes: if the voltage status is high and the controller is enabled, then the control adopts a first trailer mode to tow the vehicle, which refers to towing control across the entire speed range; if the voltage status is high and the controller is not enabled, then the control adopts a second trailer mode to tow the vehicle, which refers to controlling the motor controller based on the speed; if the voltage status is low and the controller is not enabled, then the control adopts a third trailer mode to tow the vehicle, which refers to towing control with speed limits. After the trailer status self-check, three different trailer modes are classified according to the voltage status and controller enable status, so that different motor control strategies can be adopted for towing subsequently, which can maximize the towing speed range and reduce braking torque during towing.

[0033] After determining the towing mode, towing control can be performed according to the control strategy corresponding to the towing mode. Based on this, if the first towing mode is used to control the vehicle for towing, the switching transistors in the motor controller are turned on, and the motor is controlled with zero torque; the vehicle can be towed freely within the full speed range; and the maximum allowable towing speed is fed back to the vehicle controller as the peak speed of the motor.

[0034] When the vehicle is in a high-voltage state and the controller is enabled, the motor controller unit adopts a control strategy of controller open + zero torque. With all switches in the motor controller open and zero torque enabled, free towing is allowed across the entire speed range. The switches can be Metal-Oxide-Semiconductor Field-Effect Transistors (MOS), Insulated-Gate Bipolar Transistors (IGBTs), etc., preferably IGBTs. Switch open indicates that the control switch is closed and conducting. In this first towing mode, under the towing scheme, the motor control unit feeds back the maximum allowable towing speed as the motor's peak speed in real time via CAN messages. For example, the motor's peak speed can be fed back to the vehicle controller as the maximum allowable towing speed and displayed on the instrument panel, allowing the driver to monitor the vehicle's status during towing and take appropriate measures to maximize the safety of the electronic control components.

[0035] Considering that the motor will generate back EMF if the speed is high during towing, affecting the towing, in this embodiment of the application, controlling free towing within the full speed range in the first towing mode further includes: obtaining the current speed of the motor; if the current speed is greater than a first reference speed, then looking up a preset current mapping table based on the zero torque and the current speed to obtain a magnetic weakening current corresponding to the zero torque and the current speed; and controlling the motor controller to output the magnetic weakening current. The first reference speed refers to the motor speed during towing caused by the back EMF generated by the motor, which can be set as needed and is not specifically limited here. At high speeds, the motor control unit can look up the corresponding magnetic weakening current based on the current mapping table (MAP), which can effectively counteract the back EMF of the motor at high speeds and maximize the towing speed range.

[0036] In the application embodiment, if the second trailer mode is used to control the vehicle for trailer control, the current speed of the motor is obtained; the switching of each switch in the motor controller is controlled according to the current speed to realize trailer towing; and the maximum allowable trailer speed is fed back to the vehicle controller as the rated speed of the motor.

[0037] When the vehicle is in a high-voltage state and the controller is disabled, the current motor speed is acquired, and the motor control unit adopts different control strategies based on the motor speed. When the motor speed is low, the back EMF generated by the motor during towing is less than the bus voltage, and no current flows through the motor and motor controller, which is beneficial for towing. When the motor speed is high, the back EMF generated by the motor during towing is large, potentially exceeding the bus voltage, which risks damaging components. Relevant measures need to be taken to effectively reduce the back EMF. Simultaneously, the motor speed during towing cannot be too high; the maximum permissible towing speed can be fed back to the vehicle controller as the motor's rated speed to ensure safe towing.

[0038] In this embodiment, controlling the on / off state of each switch in the motor controller based on the current rotational speed to achieve trailer operation includes: if the current rotational speed is less than or equal to a second reference rotational speed, controlling each switch in the motor controller to turn off; if the current rotational speed is greater than the second reference rotational speed, performing active short-circuit control on the motor controller, and simultaneously outputting a target temperature to control the cooling system to dissipate heat based on the target temperature, wherein the target temperature is the greater of the actual motor temperature and a preset temperature substitution value. The second reference rotational speed can be set as needed and is not specifically limited here. Preferably, the value of the second reference rotational speed is generally taken near the rated speed of the motor in practical applications, or the rated speed can be directly taken.

[0039] For the relationship between motor torque and speed, please refer to [link / reference]. Figure 2 At low motor speeds, under an active short-circuit control strategy, the torque is close to zero, which is beneficial for the trailer. However, under a full switch-off control strategy, the motor torque is negative and relatively large, indicating that the motor generates significant braking torque, which is detrimental to smooth towing. At high motor speeds, under an active short-circuit control strategy, the motor torque is close to zero, which is beneficial for the trailer. However, under a full switch-off control strategy, the motor torque is negative and relatively large, indicating that the motor generates significant braking torque, which is detrimental to smooth towing.

[0040] Based on this, in the embodiments of this application, if the current speed of the motor is less than the rated speed, the back EMF of the motor is less than the bus voltage. Therefore, there is no problem of current flowing back into the bus capacitor through the diode. No current flows through the motor and the motor controller, resulting in less heat generation, which is beneficial to the trailer. At this time, an IGBT fully off control strategy can be adopted. Compared with the active short-circuit control strategy, the braking torque generated in the fully off state is smaller, which is beneficial to the trailer's operating conditions.

[0041] If the current motor speed is greater than the second reference speed, an active short-circuit control (ASC) strategy combined with an external generator to replace temperature control can be used. ASC active short-circuit control can involve turning off the three transistors in the upper arm of the IGBT while simultaneously turning on the three transistors in the lower arm, or turning on the three transistors in the upper arm of the IGBT while simultaneously turning off the three transistors in the lower arm; this constitutes the safe operating state for active short-circuit protection. In active short-circuit operation, the motor stator windings and the IGBT in the lower arm form a closed-loop circuit. The back electromotive force (EMF) energy generated by the motor is released through the stator windings, generating a corresponding braking torque at the motor output. Increasing motor speeds generate significant back EMF. When the back EMF exceeds the bus voltage, current will flow uncontrollably through the freewheeling diode into the capacitor, causing the capacitor voltage to rise continuously, posing a risk of component damage. At high speeds, the active short-circuit (ASC) strategy can cut off the energy flow between the motor and the motor controller, while simultaneously generating a large magnetic weakening current, effectively reducing the back EMF. Compared to the full shut-off control strategy, the braking torque generated in ASC state is smaller, which is beneficial for trailer operation.

[0042] In an active short-circuit state, the phase current flowing through the motor is large, causing the motor to heat up quickly and easily leading to device damage. To prevent device damage due to high temperature, in this embodiment, a target temperature is output to control the cooling system to dissipate heat based on the target temperature. The target temperature is the greater of the actual motor temperature and a preset temperature substitution value. The actual motor temperature is the actual temperature of the motor detected in real time by a temperature sensor. The temperature substitution value is a preset temperature value used to maintain normal operation of the equipment when the temperature sensor malfunctions or the data is unreliable. The temperature substitution value is generally below 150℃, and the specific value is related to the calibration of water cooling and fan-related data on the vehicle controller. Generally, the higher the target temperature received by the vehicle controller from the motor control unit, the greater the level of coolant flow and fan cooling controlled by the motor control unit. A preferred temperature substitution value is 145℃. The target temperature T1 = MAX(actual motor temperature, temperature substitution value), that is, the target temperature is the greater of the actual motor temperature and the temperature substitution value.

[0043] When the current speed of the motor is lower than the second reference speed, the active short-circuit control is discontinued and the trailer control strategy of full IGBT shutdown is implemented. The two control strategies switch seamlessly according to the current speed of the motor, and the trailer process is uninterrupted. There is no need to stop to switch modes, which can maximize the range of trailer speed and protect components.

[0044] The motor control unit provides real-time feedback via CAN messages regarding the maximum permissible trailer speed, which is the motor's rated speed. The rated speed is communicated instead of the peak speed because, above the rated speed, although an active short-circuit control strategy is employed, prolonged operation poses a significant risk of motor overheating and demagnetization. Therefore, from the perspective of practical vehicle application, the maximum permissible trailer speed communicated in this trailer mode is the rated speed.

[0045] In this embodiment, if the vehicle is controlled to trailer in a third trailer mode, all switches in the motor controller are turned off; the maximum allowable trailer speed is fed back to the vehicle controller as the motor's rated speed. When the voltage is low and the controller is disabled, the motor control unit employs a full controller shutdown strategy, keeping the motor speed below its rated speed. Below the rated speed, with all switches off, no current flows through the motor and controller, resulting in less heat generation and temperature rise, which is beneficial for the trailer. The back EMF below the rated speed generally does not exceed the bus voltage during normal operation, so trailers below the rated speed pose no risk of damage to capacitors or other components.

[0046] like Figure 3 As shown, taking IGBTs as an example of the switching transistors in the motor controller, the motor control method in trailer mode of this application embodiment includes: Step 101: Towing instruction.

[0047] The motor control unit receives towing commands sent by the vehicle controller (VCU) via hard wire or message; the towing commands include the vehicle's high and low voltage status, towing enable, etc.

[0048] Step 102: Trailer status self-check.

[0049] The motor control unit responds to the towing command and performs a vehicle status self-check to obtain the vehicle's towing status. The towing status includes voltage status and controller enable status. Voltage status refers to the vehicle's high voltage status, specifically the bus voltage status connected to the input terminal of the motor controller. Controller enable status indicates whether a motor controller enable command signal has been received from the vehicle controller. If a motor controller enable command signal is received, it means the controller is enabled; otherwise, it means the controller is not enabled.

[0050] Step 103: High voltage and controller are enabled.

[0051] After completing the trailer status self-check, it is determined that the trailer status is high voltage and the controller is enabled, that is, the bus voltage is high voltage and the controller enable command signal is received. Based on the controller enable command signal, the motor speed and other parameters can be adjusted in real time by controlling the motor controller.

[0052] Step 104: IGBT opening + zero torque.

[0053] When the trailer is in high-voltage condition and the controller is enabled, the motor controller can be controlled upon receiving the controller enable command signal to achieve real-time closed-loop regulation of motor speed and other parameters. The motor controller unit can adopt a controller-on + zero-torque control strategy, that is, the IGBTs in the motor controller are turned on while the motor is kept at zero torque output. This prevents braking torque from being generated during towing, which is very beneficial for smooth towing.

[0054] When the current speed of the motor is greater than the first reference speed, a preset current mapping table can be looked up based on the zero torque and the current speed to obtain the field weakening current corresponding to the zero torque and the current speed, and the motor controller can be controlled to output the field weakening current, which can effectively counteract the back EMF of the motor at high speed.

[0055] Step 105: Allow free trailer to move at full speed.

[0056] Because no braking torque is generated during towing, free towing is allowed across the entire speed range. The maximum permissible towing speed is the peak speed of the motor.

[0057] Step 106: High voltage, controller not enabled.

[0058] The trailer is confirmed to be in a high-voltage state and the controller is not enabled, meaning the bus voltage is high and no controller enable command signal has been received, thus preventing real-time closed-loop regulation of motor speed and other parameters.

[0059] Step 107: Determine if the speed is lower than the second reference speed. If yes, proceed to step 110; otherwise, proceed to step 108.

[0060] When the trailer is in high-voltage condition and the controller is disabled, the second trailer mode is used for towing. The motor control unit adopts different control strategies based on the motor speed. It can determine whether the motor speed is lower than the second reference speed.

[0061] Step 108: ASC short circuit protection; external target temperature.

[0062] Considering that the motor torque approaches zero under the active short-circuit control strategy when the motor is at high speed, which is beneficial to the trailer, if the motor speed is not lower than the second reference speed, the active short-circuit control strategy can cut off the energy flow between the motor and the motor controller, while generating a large magnetic weakening current, which can effectively reduce the back EMF. Because the phase current flowing through the motor is large under active short-circuit conditions, the motor heats up quickly, which can easily lead to component damage. A target temperature can be simultaneously displayed, where the target temperature is the greater of the actual motor temperature and a preset temperature substitution value. The vehicle's cooling system can control the coolant flow rate and fan cooling level based on the target temperature. The higher the target temperature, the greater the coolant flow rate and fan cooling level controlled throughout the vehicle.

[0063] Step 109: Determine if the speed is lower than the second reference speed. If yes, proceed to step 110; otherwise, return to step 108.

[0064] During the towing process, the motor speed is checked in real time to see if it is lower than the second reference speed. If not, the process returns to step 108 and continues to use the active short-circuit control strategy.

[0065] Step 110: Turn off all IGBTs.

[0066] Considering that the motor torque is close to zero under the IGBT full shutdown strategy when the motor speed is low, which is beneficial to the trailer. If the motor speed is lower than the second reference speed, the trailer control strategy with IGBT full shutdown is executed.

[0067] Step 111: Allow the trailer to run at its rated speed.

[0068] The motor control unit provides real-time feedback via CAN messages regarding the maximum permissible trailer speed, which is the motor's rated speed, i.e., the permissible trailer speed at the rated speed.

[0069] Step 112: Low voltage, controller not enabled.

[0070] If the trailer status is determined to be low voltage and the controller is not enabled (i.e., the bus voltage is low and no controller enable command signal has been received), then real-time closed-loop regulation of motor speed and other parameters is not possible.

[0071] Step 113: Turn off all IGBTs.

[0072] The trailer control strategy of implementing full IGBT shutdown means that all IGBTs in the motor controller are turned off. No current flows through the motor and motor controller, resulting in less heat generation and temperature rise, which is beneficial to the trailer.

[0073] Step 114: Allow the trailer to run at its rated speed.

[0074] Meanwhile, the maximum permissible speed of the externally generated trailer is the rated speed, and the speed of the control motor is kept below the rated speed of the motor.

[0075] The motor control method in the trailer mode of this application embodiment comprehensively considers the high and low voltage status of the vehicle and the enabling status of the motor controller after entering the trailer mode self-test. It classifies the trailer modes and adopts the optimal targeted control strategy for each trailer mode to reduce the braking torque during the trailer process, maximize the allowable speed range of the trailer, and protect the safety of the electronic control components. During the entire trailer process, it exchanges message signals with the vehicle controller in real time and provides real-time feedback on information such as the trailer mode and the maximum allowable trailer motor speed. This allows the driver to have a clear understanding of the vehicle status throughout the trailer process and maximizes the safety of the electronic control components. If an active short circuit is entered and short circuit protection is executed, the motor control unit transmits the target temperature through a CAN message to increase the motor temperature sent to the vehicle controller, thereby increasing the cooling effect of the motor under active short circuit conditions and minimizing the risk of motor overheating and demagnetization. During the trailer process, the trailer modes and corresponding control strategies can be smoothly switched with speed according to the actual status of the vehicle. The trailer process is uninterrupted and does not require stopping to switch trailer mode states.

[0076] The motor control method in the trailer mode of this application embodiment responds to the trailer command sent by the vehicle controller, performs a vehicle status self-check, and obtains the vehicle's trailer status, which includes voltage status and controller enable status. Based on the trailer status, the vehicle's trailer mode is determined. Based on the trailer mode, the speed of each switch in the motor controller and the motor are controlled to achieve trailer towing. By adopting different control strategies for the motor under different vehicle states, excessive back EMF of the motor can be effectively suppressed, the trailer speed and allowable range can be widened to the maximum extent, the braking torque during the trailer process can be reduced, and the safety of electronic control components and passengers can be protected to the greatest extent.

[0077] In one exemplary embodiment of this specification, a motor control device in trailer mode is also provided, applied to a motor control unit. For example... Figure 4 As shown, the motor control device 400 in trailer mode includes: The status self-test module 401 is used to respond to the towing command sent by the vehicle controller, perform vehicle status self-test, and obtain the vehicle's towing status, which includes voltage status and controller enable status. The mode determination module 402 is used to determine the trailer mode of the vehicle based on the trailer status. The motor control module 403 is used to control the speed of each switch in the motor controller and the motor according to the trailer mode to realize the trailer.

[0078] In some implementations, the mode determination module 402 is configured to: if the voltage state is high voltage and the controller is enabled, control the vehicle to be towed using a first towing mode, wherein the first towing mode refers to towing control across the entire speed range; if the voltage state is high voltage and the controller is not enabled, control the vehicle to be towed using a second towing mode, wherein the second towing mode refers to controlling the motor controller based on the speed; if the voltage state is low voltage and the controller is not enabled, control the vehicle to be towed using a third towing mode, wherein the third towing mode refers to towing control with a limited speed.

[0079] In some implementations, the motor control module 403 is used to: control the switching transistors in the motor controller to turn on if the vehicle is towed in the first trailer mode, and simultaneously perform zero torque control on the motor; control the vehicle to tow freely within the full speed range; and feed back the maximum allowable trailer speed to the vehicle controller as the peak speed of the motor.

[0080] In some embodiments, the motor control module 403 is further configured to: obtain the current speed of the motor; if the current speed is greater than the first reference speed, look up a preset current mapping table based on the zero torque and the current speed to obtain the field weakening current corresponding to the zero torque and the current speed; and control the motor controller to output the field weakening current.

[0081] In some implementations, the motor control module 403 is also used to: if the vehicle is towed in a second trailer mode, obtain the current speed of the motor; control the switching of each switch in the motor controller according to the current speed to achieve trailer towing; and feed back the maximum allowable trailer speed to the vehicle controller as the rated speed of the motor.

[0082] In some embodiments, the motor control module 403 is further configured to: control each switch in the motor controller to turn off if the current speed is less than or equal to the second reference speed; and perform active short-circuit control on the motor controller if the current speed is greater than the second reference speed, while outputting a target temperature to control the cooling system to dissipate heat based on the target temperature, wherein the target temperature is the greater of the actual motor temperature and a preset temperature substitution value.

[0083] In some implementations, the motor control module 403 is also used to: control the switching transistors in the motor controller to turn off if the vehicle is towed in a third trailer mode; and feed back the maximum allowable trailer speed to the vehicle controller as the rated speed of the motor.

[0084] In some implementations, the status self-test module 401 is used to: perform a vehicle fault self-test; if a fault exists that prevents towing, control the exit from towing mode and output whether towing is enabled; self-test whether the current voltage is high or low, and obtain the voltage status; detect whether a controller enable command sent by the vehicle controller has been received, and determine the controller enable status.

[0085] This application embodiment also provides a vehicle, including: the motor control device in trailer mode described above.

[0086] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0087] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0088] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0089] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0090] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0091] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A motor control method in trailer mode, characterized in that, The motor control method includes: In response to the towing command sent by the vehicle controller, the vehicle performs a self-check of its status and obtains the vehicle's towing status, which includes the voltage status and the controller enable status. The towing mode of the vehicle is determined based on the towing status; The trailer mode is controlled by adjusting the switching transistors in the motor controller and the speed of the motor to achieve trailer operation.

2. The method according to claim 1, characterized in that, Determining the towing mode of the vehicle based on the towing status includes: If the voltage state is a high voltage state and the controller is enabled, the control adopts the first trailer mode to trailer control the vehicle. The first trailer mode refers to trailer control across the entire speed range. If the voltage state is high voltage and the controller is not enabled, the control adopts the second trailer mode to trailer control the vehicle. The second trailer mode refers to controlling the motor controller according to the rotation speed. If the voltage state is low and the controller is not enabled, the control adopts a third trailer mode to trailer control the vehicle, which refers to trailer control with a limited speed.

3. The method according to claim 2, characterized in that, The step of controlling the switching transistors in the motor controller and the speed of the motor according to the trailer mode to realize trailer operation includes: If the first trailer mode is used to control the vehicle for trailering, the switching transistors in the motor controller are turned on, and the motor is controlled to have zero torque. Controlled towing freedom across the entire speed range; The maximum permissible trailer speed is fed back to the vehicle controller as the peak speed of the motor.

4. The method according to claim 3, characterized in that, The control of free trailer movement across the entire speed range also includes: Get the current speed of the motor; If the current rotational speed is greater than the first reference rotational speed, then a preset current mapping table is looked up based on the zero torque and the current rotational speed to obtain the magnetic weakening current corresponding to the zero torque and the current rotational speed. The motor controller outputs the weakening magnetic current.

5. The method according to claim 2, characterized in that, The step of controlling the switching transistors in the motor controller and the speed of the motor according to the trailer mode to realize trailer operation includes: If the second trailer mode is used to control the vehicle for trailering, then obtain the current speed of the motor; The on / off state of each switch in the motor controller is controlled according to the current speed to realize the trailer; The maximum permissible trailer speed is fed back to the vehicle controller as the rated speed of the motor.

6. The method according to claim 5, characterized in that, The step of controlling the on / off state of each switch in the motor controller according to the current speed to realize trailer operation includes: If the current rotational speed is less than or equal to the second reference rotational speed, then control the switching transistors in the motor controller to turn off; If the current speed is greater than the second reference speed, the motor controller is actively short-circuited, and a target temperature is output to control the cooling system to dissipate heat based on the target temperature. The target temperature is the greater of the actual motor temperature and a preset temperature substitution value.

7. The method according to claim 2, characterized in that, The step of controlling the switching transistors in the motor controller and the speed of the motor according to the trailer mode to realize trailer operation includes: If the third trailer mode is used to control the vehicle for trailering, then the switching transistors in the motor controller are turned off. The maximum permissible trailer speed is fed back to the vehicle controller as the rated speed of the motor.

8. The method according to claim 1, characterized in that, The process of performing a vehicle status self-check and obtaining the vehicle's towing status includes: Perform a vehicle fault self-check. If a fault is found that prevents towing, control the exit from towing mode and output towing enable or disable. The system checks whether the current voltage is high or low and obtains the voltage status. Detect whether a controller enable command sent by the vehicle controller has been received, and determine the controller enable status.

9. A motor control device in trailer mode, characterized in that, The device includes: The status self-test module is used to respond to the towing command sent by the vehicle controller, perform vehicle status self-test, and obtain the vehicle's towing status, which includes voltage status and controller enable status. The mode determination module is used to determine the vehicle's towing mode based on the towing status. The motor control module is used to control the speed of each switch in the motor controller and the motor according to the trailer mode to realize the trailer.

10. A vehicle, characterized in that, The vehicle includes: a motor control device in trailer mode as described in claim 9.

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