A motor controller, braking system and electric vehicle implementing redundant braking

Abstract

This application provides a motor controller, braking system, and electric vehicle for implementing redundant braking, applicable to the field of electric vehicle technology. The motor controller includes a motor controller housing and a motor control motherboard. The motor controller housing has a first communication interface, which includes a first CAN communication terminal and a second CAN communication terminal. The first CAN communication terminal is used to connect the motor control motherboard and the vehicle controller, and the second CAN communication terminal is used to connect the motor control motherboard and the brake controller. The motor controller can communicate directly with the vehicle controller to achieve coordinated control at the vehicle level. Simultaneously, the motor controller can also communicate directly with the brake controller. When the braking system loses braking capability or its braking capability is insufficient, the drive motor assists in braking, fully utilizing the drive motor to enhance the braking capability of the electric vehicle and achieving redundant braking functionality.

Description

Technical Field

[0001] This application relates to the field of electric vehicle technology, and more particularly to a motor controller, braking system, and electric vehicle that implements redundant braking. Background Technology

[0002] During the operation of electric vehicles, deceleration and stopping are typically achieved through the braking system. When the braking system loses its braking ability or its braking ability is insufficient, the drive system can provide some braking force when in energy recovery mode. However, the motor controller does not have the ability to independently execute braking control, which leads to a delay in the response of braking control, posing a safety risk to the electric vehicle. Summary of the Invention

[0003] This application provides a motor controller, braking system, and electric vehicle for achieving redundant braking. By establishing a line between the motor controller and the brake controller that enables direct communication between the two, the braking capability of the electric vehicle is enhanced by fully utilizing the drive motor, thereby realizing the redundant braking function of the electric vehicle.

[0004] In a first aspect, embodiments of this application provide a motor controller for implementing redundant braking.

[0005] The motor controller includes a motor controller housing and a motor control main board fixed in the motor controller housing. The motor controller is used to control the drive motor to output drive torque or braking torque to drive or brake the electric vehicle according to the instructions of the vehicle controller or brake controller. The motor controller housing is provided with a first communication interface, which includes a first CAN communication terminal and a second CAN communication terminal, wherein: One end of the first CAN communication terminal is used to connect to the motor control motherboard, and the other end of the first CAN communication terminal is used to connect to the vehicle controller through the first CAN communication line. The motor controller receives the drive command output by the vehicle controller according to the opening of the accelerator pedal through the first CAN communication line and controls the drive motor to output drive torque. The direction of the drive torque is the same as the direction of the drive motor speed. One end of the second CAN communication terminal is used to connect to the motor control motherboard, and the other end of the second CAN communication terminal is used to connect to the brake controller through the second CAN communication line. The motor controller receives the braking command output by the brake controller according to the opening of the brake pedal through the second CAN communication line and controls the drive motor to output braking torque. The direction of the braking torque is opposite to the direction of the rotation speed of the drive motor. The brake controller is also used to control the braking devices at the four wheels of the electric vehicle to output braking force to the brake discs of the four wheels to brake the electric vehicle.

[0006] In this embodiment, the motor controller can communicate directly with the vehicle controller via the first CAN communication line. The vehicle controller can control the drive motor to output drive torque based on the driver's intention to operate the accelerator pedal and the electric vehicle's status parameters (such as the status of the power battery and the electric vehicle's operating conditions). It can also adjust relevant controls based on feedback from the motor controller (such as the drive motor's temperature, actual torque, and fault status), achieving coordinated control at the vehicle level. Simultaneously, the motor controller can also communicate directly with the brake controller via the second CAN communication line. When the braking system loses its braking capability or its braking capability is insufficient, the brake controller can interact with the motor controller via the second CAN communication line, allowing the drive motor to output braking torque in coordination. This fully utilizes the drive motor to enhance the electric vehicle's braking capability, achieving redundant braking functionality.

[0007] In one embodiment of the first aspect, the motor controller receives a signal from the brake controller forwarded by the vehicle controller via a first CAN communication line.

[0008] In this embodiment, the motor controller can receive signals from the brake controller through two channels: one is to receive signals directly through the second CAN communication line, and the other is to receive signals forwarded by the vehicle controller through the first CAN communication line. The two can achieve redundancy backup.

[0009] In one embodiment of the first aspect, the motor controller is configured to: receive a safety status signal sent by the brake controller via a first CAN communication line and receive a safety status signal forwarded from the brake controller by the vehicle controller via a second CAN communication line; and determine that the brake controller has failed or at least one wheel-end brake device has failed when no safety status signal is received via either of the two CAN communication lines or when both safety status signals received via the two CAN communication lines indicate a fault.

[0010] Among them, the safety status signal can indicate whether the brake controller has failed and the number and location of the failed wheel-end brakes among the four wheel-end brakes.

[0011] In this embodiment, the motor controller receives safety status signals from the brake controller through two channels: one is by directly receiving the safety status signal through the second CAN communication line, and the other is by receiving the safety status signal forwarded by the vehicle controller through the first CAN communication line. This dual-channel verification prevents single-point communication failures—that is, if the motor controller receives a faulty safety status signal from either the first CAN communication line or the second CAN communication line—from mistakenly triggering the redundant braking function. Furthermore, after determining that the failure is not a single point, the motor controller can determine whether the brake controller or the wheel-end braking device has failed, as well as the number and location of the failures, based on the safety status signal. This facilitates precise execution of corresponding control after the redundant braking function is triggered.

[0012] In one embodiment of the first aspect, the motor controller is configured to: when the brake controller fails during the process of controlling the output drive torque of the drive motor, before the opening of the brake pedal of the electric vehicle begins to increase, control the drive motor to stop outputting drive torque and control the drive motor to output braking torque to decelerate and stop the electric vehicle.

[0013] In this embodiment, if the brake controller fails during the process of controlling the output drive torque of the drive motor, and before the opening of the brake pedal of the electric vehicle begins to increase, i.e. before the driver operates the brake pedal, there is no need to wait for the driver to operate the brake pedal. The motor controller controls the drive motor to stop outputting drive torque and controls the drive motor to output braking torque to decelerate and stop the electric vehicle, thus ensuring the driving safety of the electric vehicle in the event of brake controller failure.

[0014] In one embodiment of the first aspect, the motor controller is configured to: during the process of controlling the output braking torque of the drive motor, when the opening of the accelerator pedal increases, control the drive motor to continue outputting braking torque to decelerate and stop the electric vehicle.

[0015] In this embodiment, if the brake controller fails, the motor controller will also not respond to the driver's intention to operate the accelerator pedal, even if the driver has a strong intention to accelerate the electric vehicle. The motor controller will continue to output braking torque by controlling the drive motor to decelerate and stop the electric vehicle, thus ensuring the driving safety of the electric vehicle in the event of brake controller failure.

[0016] In one embodiment of the first aspect, the motor controller is configured to: when at least one wheel-end braking device fails, during the process of increasing the opening of the accelerator pedal of the electric vehicle, control the drive motor to output drive torque and the drive torque increases with the increase of the opening of the accelerator pedal; when the brake controller fails, actively control the drive motor to stop outputting drive torque and prevent it from increasing with the increase of the opening of the accelerator pedal.

[0017] In this embodiment, when the driver operates the accelerator pedal, the brake controller fails, and the braking system loses its braking capability. The motor controller actively controls the drive motor to stop outputting drive torque, and this torque does not increase with the increase in the accelerator pedal opening. In other words, acceleration of the electric vehicle is not permitted, and the electric vehicle is directly controlled to decelerate and stop, ensuring the driving safety of the electric vehicle. When at least one wheel-end braking device fails, the motor controller actively controls the drive motor to stop outputting drive torque, and this torque does not increase with the increase in the accelerator pedal opening. This allows the electric vehicle to accelerate or decelerate as desired, ensuring a smooth driving experience.

[0018] In one embodiment of the first aspect, the motor controller is configured to: during the acceleration of an electric vehicle with at least one wheel-end braking device failing, before the vehicle speed accelerates to a vehicle speed threshold, control the drive torque output by the drive motor to increase with the increase of the opening of the accelerator pedal; and during the acceleration of an electric vehicle with at least one wheel-end braking device failing, when the vehicle speed accelerates to the vehicle speed threshold, control the drive torque output by the drive motor not to increase with the increase of the opening of the accelerator pedal.

[0019] Among them, the speed threshold is the maximum speed at which electric vehicles are allowed to travel.

[0020] In this embodiment, by setting a speed threshold, the maximum speed allowed for the electric vehicle is limited to the braking capacity of the electric vehicle. This allows the electric vehicle to accelerate within a range below the speed threshold during acceleration when at least one wheel-end braking device fails. The motor controller controls the drive torque output by the drive motor to increase as the accelerator pedal opening increases, allowing the electric vehicle to accelerate according to the driver's acceleration intention and ensuring a good driving experience. However, when the electric vehicle's speed equals the speed threshold, the motor controller controls the drive torque output by the drive motor to not increase as the accelerator pedal opening increases, preventing the electric vehicle from continuing to accelerate and ensuring driving safety.

[0021] In one embodiment of the first aspect, the vehicle speed threshold of the electric vehicle is greater when all four wheel-end braking devices are effective and the brake controller is effective than the vehicle speed threshold when at least one wheel-end braking device fails.

[0022] In this embodiment, the electric vehicle has strong braking capability when all four wheel-end braking devices are effective and the brake controller is effective; the electric vehicle's braking capability weakens when at least one wheel-end braking device fails. The motor controller actively controls the electric vehicle's speed threshold when all four wheel-end braking devices are effective and the brake controller is effective to be higher than the speed threshold when at least one wheel-end braking device fails, thus limiting the maximum permissible speed of the electric vehicle within its braking capability range and ensuring driving safety.

[0023] In one embodiment of the first aspect, the more wheel-end brake devices that fail, the lower the vehicle speed threshold.

[0024] In this embodiment, the more wheel-end braking devices that fail, the weaker the braking ability of the electric vehicle. By limiting the speed threshold to a smaller value, i.e. limiting the maximum speed that the electric vehicle is allowed to travel to to a smaller value, the maximum speed of the electric vehicle can be limited to the range of the electric vehicle's braking ability under different braking conditions, thereby ensuring the driving safety of the electric vehicle.

[0025] In one embodiment of the first aspect, the vehicle speed threshold of the electric vehicle is less when the brakes at both wheel ends on the same side fail than when the brakes at both wheel ends on the same axle fail.

[0026] In this embodiment, if the brakes on both wheels on the same side fail, the electric vehicle will experience a yaw moment during braking, causing it to veer. The vehicle will veer first due to the failure, and the driver will find it difficult to manually correct the trajectory, resulting in a high risk of instability. However, if the brakes on both wheels on the same axle fail, the electric vehicle will not veer, and the risk of instability is lower. By setting the speed threshold for the electric vehicle in the case of brake failure on both wheels on the same side to be lower than that in the case of brake failure on both wheels on the same axle, the higher the risk of instability, the lower the maximum speed limit. This ensures that the maximum speed of the electric vehicle can be limited regardless of the risk of instability, thereby guaranteeing driving safety.

[0027] In one embodiment of the first aspect, the motor controller is configured to: during braking in a braking process where at least one wheel-end braking device fails, when the opening of the brake pedal of the electric vehicle begins to increase, control the drive motor to output braking torque according to a braking command, and the braking torque increases as the opening of the brake pedal increases.

[0028] The braking command indicates the value of braking torque that the brake controller needs from the drive motor.

[0029] In this embodiment, during braking when at least one wheel-end braking device fails, the braking capability of the electric vehicle is jointly provided by the braking force output from the effective wheel-end braking devices and the braking torque output from the drive motor. When the opening of the electric vehicle's brake pedal begins to increase, the motor controller receives braking commands sent by the brake controller via the second CAN communication line, controlling the drive motor to output braking torque. This braking torque increases with the increase in the opening of the brake pedal, assisting the braking system in braking. This ensures that the electric vehicle can still be braked according to the driver's intention to operate the brake pedal even when at least one wheel-end braking device fails. Furthermore, compared to braking commands forwarded via domain control, the timeliness of brake command reception is improved.

[0030] In one embodiment of the first aspect, the motor controller is configured to: during the process of controlling the output braking torque of the drive motor, when the wheels of the electric vehicle slip, before the opening of the brake pedal begins to decrease, actively control the drive motor to reduce the output braking torque until the wheels no longer slip; and after the wheels no longer slip, actively control the drive motor to restore the output braking torque.

[0031] In this embodiment, if at least one wheel-end braking device fails, during the process of controlling the output braking torque of the drive motor, if the electric vehicle's wheel slips, for example, if the wheel is traveling on a low-friction surface, continuing to output the same amount of braking torque will cause the wheel to lock up or rotate in the opposite direction, resulting in instability of the electric vehicle. When the wheel controlled by the motor controller slips, the motor controller actively controls the drive motor to reduce the output braking torque before the brake pedal opening begins to decrease, to avoid continuing to output braking torque and causing the wheel to lock up or rotate in the opposite direction, thus preventing instability of the electric vehicle. After the wheel stops slipping, the motor controller actively controls the drive motor to restore the output braking torque, promptly restoring the braking torque of the brake motor and ensuring the braking efficiency of the electric vehicle.

[0032] In one embodiment of the first aspect, the motor controller is configured to: the greater the difference between the deceleration of the electric vehicle and the deceleration of the drive motor, the greater the reduction in the braking torque output by the actively controlled drive motor.

[0033] In this embodiment, the greater the difference between the deceleration of the electric vehicle and the deceleration of the drive motor, the more severe the wheel slippage. In this case, the motor controller actively controls the reduction of the braking torque output by the drive motor to achieve the goal of preventing the electric vehicle from becoming unstable under different degrees of wheel slippage by reducing the braking torque output by the drive motor.

[0034] In one embodiment of the first aspect, the motor controller is configured to: during the process of controlling the output drive torque of the drive motor, when the wheels of the electric vehicle slip, before the opening of the accelerator pedal begins to decrease, actively control the drive motor to reduce the output drive torque until the wheels no longer slip; and after the wheels no longer slip, actively control the drive motor to restore the output drive torque.

[0035] In this embodiment, if at least one wheel-end braking device fails, during the process of controlling the output drive torque of the drive motor, if the electric vehicle's wheel slips, for example, if the wheel is traveling on a low-friction surface, continuing to output the drive torque will cause the wheel to excessively slip, thereby causing the electric vehicle to become unstable. When the wheel controlled by the motor controller slips, the motor controller actively controls the drive motor to reduce the output drive torque before the accelerator pedal opening begins to decrease, to avoid continuing to output drive torque and causing the wheel to excessively slip, thus preventing the electric vehicle from becoming unstable. After the wheel stops slipping, the motor controller actively controls the drive motor to restore the output drive torque, promptly restoring the drive torque of the brake motor and ensuring the driving efficiency of the electric vehicle.

[0036] In one embodiment of the first aspect, the motor controller is configured to: the greater the difference between the acceleration of the drive motor and the acceleration of the electric vehicle, the greater the reduction in the drive torque output by the actively controlled drive motor.

[0037] In this embodiment, the greater the difference between the acceleration of the drive motor and the acceleration of the electric vehicle, the more severe the wheel slippage. In this situation, the motor controller actively controls the reduction of the drive torque output by the drive motor to prevent the electric vehicle from becoming unstable under varying degrees of wheel slippage.

[0038] In one embodiment of the first aspect, the motor controller is configured to: during the process of controlling the output braking torque of the drive motor, when the difference between the first yaw rate from the inertial measurement unit and the second yaw rate calculated based on the wheel speeds of the four wheels is greater than the first difference, the motor controller actively controls the drive motor to reduce the output braking torque; when the difference between the first yaw rate and the second yaw rate decreases to less than the second difference, the motor controller actively controls the drive motor to restore the output braking torque.

[0039] Among them, the first yaw rate is the actual value of the yaw rate, and the second yaw rate is the calculated value of the yaw rate.

[0040] In this embodiment, when the difference between the first yaw rate and the second yaw rate is greater than the first difference, for example, when the electric vehicle is traveling on a split road, it indicates that the yaw rate of the electric vehicle deviates from the expected value, and continuing to output the braking torque will cause the electric vehicle to lose directional stability. When the difference between the first yaw rate and the second yaw rate decreases to less than the second difference, it indicates that the directional stability of the electric vehicle is relatively high. In the event of failure of at least one wheel-end braking device, during the process of controlling the output braking torque of the drive motor, when the electric vehicle loses directional stability, the motor controller actively controls the drive motor to reduce the output braking torque to avoid further output of braking torque causing the electric vehicle to lose stability. After the directional stability of the electric vehicle is relatively high, the motor controller actively controls the drive motor to restore the output braking torque, promptly restoring the braking torque of the brake motor and ensuring the braking efficiency of the electric vehicle.

[0041] In one embodiment of the first aspect, the motor controller is configured to: during the process of controlling the output drive torque of the drive motor, when the difference between the first yaw rate and the second yaw rate is greater than the first difference, the motor controller actively controls the drive motor to reduce the output drive torque; when the difference between the first yaw rate and the second yaw rate decreases to the second difference, the motor controller actively controls the drive motor to restore the output drive torque.

[0042] In this embodiment, when at least one wheel-end braking device fails, during the process of controlling the output driving torque of the drive motor, if the electric vehicle loses its direction, the motor controller actively controls the drive motor to reduce the output driving torque to avoid the electric vehicle from losing its stability due to continued output of driving torque. After the electric vehicle's direction stability is relatively high, the motor controller actively controls the drive motor to restore the output driving torque, thereby timely restoring the drive torque of the drive motor and ensuring the driving efficiency of the electric vehicle.

[0043] In one embodiment of the first aspect, the motor controller is configured to: during the process of controlling the output braking torque of the drive motor, during the straight-line movement of the electric vehicle, before the steering wheel of the electric vehicle begins to turn, when the yaw rate of the electric vehicle is greater than a first preset yaw rate, actively control the drive motor to reduce the output braking torque; when the yaw rate is reduced to less than a second preset yaw rate, actively control the drive motor to restore the output braking torque.

[0044] Here, "the yaw rate of the electric vehicle is greater than the preset yaw rate" refers to the actual value of the yaw rate.

[0045] In this embodiment, if the yaw rate of the electric vehicle is greater than a first preset yaw rate, it indicates that the yaw rate of the electric vehicle deviates from the expected value, and continuing to output the braking torque will cause the electric vehicle to lose directional stability. When the yaw rate decreases to a second preset yaw rate, it indicates that the directional stability of the electric vehicle is relatively high. In the event of failure of at least one wheel-end braking device, during the process of controlling the output braking torque of the drive motor, when the electric vehicle loses directional stability, the motor controller actively controls the drive motor to reduce the output braking torque to avoid further output of braking torque causing the electric vehicle to lose stability. After the directional stability of the electric vehicle is relatively high, the motor controller actively controls the drive motor to restore the output braking torque, promptly restoring the braking torque of the brake motor and ensuring the braking efficiency of the electric vehicle.

[0046] In one embodiment of the first aspect, during the process of controlling the output drive torque of the drive motor, during the straight-line movement of the electric vehicle, before the steering wheel of the electric vehicle begins to turn, when the yaw rate of the electric vehicle is greater than a first preset yaw rate, the motor controller actively controls the drive motor to reduce the output drive torque; when the yaw rate is reduced to less than a second preset yaw rate, the motor controller actively controls the drive motor to restore the output drive torque.

[0047] In this embodiment, when at least one wheel-end braking device fails, during the process of controlling the output driving torque of the drive motor, if the electric vehicle loses its direction, the motor controller actively controls the drive motor to reduce the output driving torque to avoid the electric vehicle from losing its stability due to continued output of driving torque. After the electric vehicle's direction stability is relatively high, the motor controller actively controls the drive motor to restore the output driving torque, thereby timely restoring the drive torque of the drive motor and ensuring the driving efficiency of the electric vehicle.

[0048] In one embodiment of the first aspect, when the low-voltage power supply system of the electric vehicle fails, before the opening of the brake pedal of the electric vehicle begins to increase, the motor controller actively controls the drive motor to output braking torque to decelerate and stop the electric vehicle; after the opening of the accelerator pedal of the electric vehicle begins to increase, the motor controller actively controls the drive motor to stop outputting driving torque and not increase it with the increase of the opening of the accelerator pedal.

[0049] In this embodiment, when the low-voltage power supply system of the electric vehicle fails, before the brake pedal opening begins to increase (i.e., before the driver operates the brake pedal), the motor controller actively controls the drive motor to output braking torque to decelerate and stop the electric vehicle without waiting for a response from the driver to operate the brake pedal, thus improving the driving safety of the electric vehicle. Furthermore, after the accelerator pedal opening begins to increase, the motor controller actively controls the drive motor to stop outputting driving torque, and this torque does not increase with the increase in the accelerator pedal opening; that is, the electric vehicle is not allowed to accelerate, and the controller directly controls the electric vehicle to decelerate and stop, ensuring the driving safety of the electric vehicle.

[0050] In one embodiment of the first aspect, the motor controller is specifically configured to: during the process of controlling the output braking torque of the drive motor, when the deceleration of the drive motor is greater than a first preset deceleration, actively control the drive motor to reduce the output braking torque before the opening of the brake pedal of the electric vehicle begins to decrease; and when the deceleration of the drive motor decreases to less than a second preset deceleration, actively control the drive motor to restore the output braking torque.

[0051] In this embodiment, if the deceleration of the electric vehicle is greater than a first preset deceleration, it indicates a higher risk of wheel lock-up or reverse acceleration. If the deceleration of the electric vehicle is less than a second preset deceleration, it indicates lower braking efficiency. When the risk of wheel lock-up or reverse acceleration is high, the motor controller actively controls the drive motor 113 to reduce the output braking torque before the brake pedal opening begins to decrease, thereby reducing the deceleration of the drive motor. When the deceleration of the drive motor decreases to a point where the braking efficiency of the electric vehicle is low, the motor controller actively controls the drive motor to restore the output braking torque, promptly restoring the braking torque and ensuring the braking efficiency of the electric vehicle.

[0052] In one embodiment of the first aspect, the greater the deceleration of the electric vehicle, the greater the reduction in the braking torque output by the drive motor actively controlled by the motor controller.

[0053] In this embodiment, the greater the deceleration of the electric vehicle, the greater the reduction in braking torque output by the drive motor actively controlled by the motor controller. This enables the electric vehicle to reduce deceleration by actively reducing braking torque under different deceleration conditions, thereby preventing wheel lock-up or reverse acceleration.

[0054] Secondly, embodiments of this application provide a braking system, which includes four wheel-end braking devices and a brake controller. The brake controller includes a brake controller housing and a brake control main board fixed in the brake controller housing. The brake controller is used to control the four wheel-end braking devices to output braking force to the brake discs of the four wheels to brake the electric vehicle according to the braking command of the vehicle controller. The brake controller housing is provided with a second communication interface, which includes a third CAN communication terminal, a fourth CAN communication terminal, and wheel-end CAN communication terminals, wherein: One end of the third CAN communication terminal is used to connect to the brake control main board, and the other end of the third CAN communication terminal is used to connect to the vehicle controller through the third CAN communication line. One end of the fourth CAN communication terminal is used to connect to the brake control main board, and the other end of the fourth CAN communication terminal is used to connect to the motor controller through the second CAN communication line. The motor controller is used to control the drive motor to output drive torque or braking torque to drive or brake the electric vehicle according to the instructions of the vehicle controller or the brake controller. One end of the wheel-end CAN communication terminal is used to connect to the brake control main board, and the other end of the wheel-end CAN communication terminal is used to connect to the wheel-end braking device through the fourth CAN communication line. The brake controller is also used to control the four wheel-end braking devices of the electric vehicle to output braking force to the brake discs of the four wheels through the fourth CAN communication line to brake the electric vehicle.

[0055] In this embodiment, the brake controller can communicate directly with the vehicle controller via the third CAN communication line. The vehicle controller can control the braking system to output braking force based on the driver's intentions and the electric vehicle's status parameters (such as the status of the power battery and the operating condition of the electric vehicle), and adjust relevant controls based on information fed back by the brake controller (such as actual braking force and fault status), thus achieving coordinated control at the vehicle level. The brake controller can also communicate directly with the motor controller via the second CAN communication line. When the braking system loses its braking capability or its braking capability is insufficient, the brake controller can interact with the motor controller via the second CAN communication line, allowing the drive motor to cooperate in performing braking, fully utilizing the drive motor to enhance the electric vehicle's braking capability and achieving redundant braking function. Furthermore, it controls the wheel-end braking devices to output braking force via the fourth CAN communication line.

[0056] Thirdly, embodiments of this application provide an electric vehicle, which includes a drive system, a braking system, and a vehicle controller. The drive system includes at least one drive motor and at least one motor controller. Each motor controller includes a motor controller housing and a motor control main board fixed in the motor controller housing. The at least one motor controller is used to control at least one drive motor to output drive torque or braking torque to drive or brake the electric vehicle according to instructions from the vehicle controller or the braking controller. Each motor controller housing is provided with a first communication interface, which includes a first CAN communication terminal and a second CAN communication terminal. The braking system includes four wheel-end braking devices and a brake controller. The brake controller includes a brake controller housing and a brake control main board fixed in the brake controller housing. The brake controller is used to control the four wheel-end braking devices to output braking force to the brake discs of the four wheels to brake the electric vehicle according to braking instructions from the vehicle controller. The brake controller housing is provided with a second communication interface, which includes a third CAN communication terminal, a fourth CAN communication terminal, and wheel-end CAN communication terminals, wherein: One end of the first CAN communication terminal is used to connect to the motor control main board, and the other end of the first CAN communication terminal is used to connect to the vehicle controller through the first CAN communication line. One end of the second CAN communication terminal is used to connect to the motor control main board, and the other end of the second CAN communication terminal is used to connect to one end of the third CAN communication terminal through the second CAN communication line. The other end of the third CAN communication terminal is used to connect to the brake control main board, and the other end of the fourth CAN communication terminal is used to connect to the vehicle controller through the third CAN communication line. One end of the wheel-end CAN communication terminal is used to connect to the brake control main board, and the other end of the wheel-end CAN communication terminal is used to connect to the wheel-end braking device through the fourth CAN communication line. The brake controller is also used to control the four wheel-end braking devices of the electric vehicle to output braking force to the brake discs of the four wheels to brake the electric vehicle through the fourth CAN communication line.

[0057] The supplementary solutions and technical effects provided in the second and third aspects above can be found in the corresponding descriptions in the first aspect, and will not be repeated here. Attached Figure Description

[0058] Figure 1 A schematic diagram of an electric vehicle provided in an embodiment of this application is shown; Figure 2 A schematic diagram of a driving system provided in an embodiment of this application is shown; Figure 3 A schematic diagram of a braking system provided in an embodiment of this application is shown; Figure 4 A schematic diagram of a communication architecture for an electric vehicle provided in an embodiment of this application is shown; Figure 5 A schematic diagram of the structure of a motor controller provided in an embodiment of this application is shown; Figure 6 A timing diagram of a safety state signal and a brake controller survival counter provided in an embodiment of this application is shown; Figure 7 A timing diagram showing a second braking command, the torque output by the drive motor, and the speed of the electric vehicle provided in an embodiment of this application is shown. Figure 8 A timing diagram of the accelerator pedal opening and drive torque provided in an embodiment of this application is shown; Figure 9 This application provides a timing diagram showing the opening degree of the accelerator pedal, the opening degree of the brake pedal, the second braking command, the torque output by the drive motor, and the speed of the electric vehicle. Figure 10 This illustration shows a schematic diagram of the difference in acceleration and the torque output by the drive system according to an embodiment of this application; Figure 11 This illustration shows a schematic diagram of the difference in yaw rate and the output torque of the drive motor according to an embodiment of this application; Figure 12 A schematic diagram of acceleration and braking torque provided in an embodiment of this application is shown; Figure 13 A schematic diagram of a braking system provided in an embodiment of this application is shown; Figure 14 This paper illustrates a schematic diagram of a system architecture for implementing redundant braking functionality according to an embodiment of this application. Figure 15 A schematic diagram of a communication architecture for an electric vehicle provided in an embodiment of this application is shown. Detailed Implementation

[0059] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0060] The use of prefixes such as "first" and "second" in this application embodiment is solely for distinguishing different descriptive objects and does not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes to distinguish descriptive objects in this application embodiment does not constitute a limitation on the described objects. The description of the described objects is found in the claims or the context of the embodiments, and the use of such prefixes should not constitute unnecessary restrictions.

[0061] When the braking system fails, the drive system can provide some braking force when in energy recovery mode, but the motor controller does not have the ability to independently execute braking control, and there is a safety risk in driving electric vehicles.

[0062] Therefore, this application provides a motor controller, braking system, and electric vehicle for implementing redundant braking. The motor controller includes a motor controller housing and a motor control mainboard fixed in the motor controller housing. The motor controller housing is provided with a first communication interface, which includes a first CAN communication terminal and a second CAN communication terminal. One end of the first CAN communication terminal is used to connect to the motor control mainboard, and the other end is used to connect to the vehicle controller via a first CAN communication line. One end of the second CAN communication terminal is used to connect to the motor control mainboard, and the other end is used to connect to the brake controller via a second CAN communication line. The motor controller can communicate directly with the vehicle controller via the first CAN communication line to achieve vehicle-level coordinated control. Simultaneously, the motor controller can also communicate directly with the brake controller via the second CAN communication line. When the braking system loses braking capability or has insufficient braking capability, the drive motor assists in braking, fully utilizing the drive motor to enhance the braking capability of the electric vehicle and achieving redundant braking functionality.

[0063] See Figure 1 , Figure 1 A schematic diagram of an electric vehicle provided in an embodiment of this application is shown. (As shown) Figure 1 As shown, the electric vehicle 100 includes a drive system 110, a braking system 120, a power battery 130, and a vehicle controller 140. The drive system 110 drives the electric vehicle 100. The power battery 130 provides electrical energy to the drive system 110. The vehicle controller 140 controls the drive system 110.

[0064] Based on their position within the electric vehicle 100, the wheels can be categorized as follows: left front wheel (FL), right front wheel (FR), left rear wheel (BL), and right rear wheel (BR). In terms of axle arrangement, the left and right front wheels are coaxial and connected via the front axle. The left and right rear wheels are coaxial and connected via the rear axle. In terms of position, the left and left rear wheels are on the same side (left side), and the right front and right rear wheels are on the same side (right side). In other words, in the electric vehicle 100, the left and right front wheels are coaxial, as are the left and right rear wheels; the left and left rear wheels are on the same side, as are the right and right rear wheels.

[0065] See Figure 2 , Figure 2 A schematic diagram of a driving system provided in an embodiment of this application is shown.

[0066] Figure 2The electric vehicle 100 shown in (a) is a two-wheel drive model. The drive system 110 includes two front wheel drive motors 111 and a motor controller 121 for the drive motors 111, and two rear wheel drive motors 112 and a motor controller 122 for the drive motors 112.

[0067] When the electric vehicle 100 is in a driving state, each drive motor in the drive system 110 provides driving force to the electric vehicle 100. Specifically, when the electric vehicle 100 is in a driving state, the vehicle controller 140 calculates the torque demand of the electric vehicle and outputs drive commands to the motor controllers of each drive motor. Each motor controller receives power from the power battery 130 (e.g., Figure 1 The electrical energy (as shown) is used to control the corresponding drive motor to output the torque indicated by the drive command.

[0068] When the electric vehicle 100 is in a driving state, during the forward movement of the electric vehicle 100, each drive motor supplies driving torque to the wheels of the electric vehicle 100 to provide driving force. The driving torque is in the same direction as the wheel rotation when the electric vehicle is moving forward. During the reverse movement of the electric vehicle 100, each drive motor supplies braking torque to the wheels of the electric vehicle 100 to provide driving force. The braking torque is in the same direction as the wheel rotation when the electric vehicle is moving backward.

[0069] In particular, each drive motor in the electric vehicle 100 with energy recovery function can also be used to provide braking force for the electric vehicle 100. Specifically, when the electric vehicle 100 is in a braking state, the vehicle controller 140 receives a braking signal and sends an energy recovery command to each motor controller. Each motor controller responds to the energy recovery command and controls the corresponding drive motor to operate in a power generation state. Each drive motor converts the kinetic energy of the electric vehicle's wheels into electrical energy and outputs braking torque to the wheels of the electric vehicle 100 to provide braking force for the electric vehicle 100.

[0070] See Figure 2 The electric vehicle 100 shown in (b) is a four-wheel drive model. The drive system 110 includes a drive motor 113 for the left front wheel and a motor controller 123 for the drive motor 113, a drive motor 114 for the right front wheel and a motor controller 124 for the drive motor 114, a drive motor 115 for the left rear wheel and a motor controller 125 for the drive motor 115, and a drive motor 116 for the right rear wheel and a motor controller 126 for the drive motor 116.

[0071] in, Figure 2 The drive system 110 shown is merely exemplary. The electric vehicle 100 can also be a single-drive model, a three-drive model with one front and two rear wheels (two front wheels are driven by one drive motor, and two rear wheels are driven by two drive motors respectively), or a three-drive model with two front and one rear wheels.

[0072] The braking system 120 can be an electro-hydraulic braking system (EHB) or an electro-mechanical braking system (EMB). Because EMB offers advantages over EHB such as faster response, higher precision, and no fluid leakage, it significantly improves safety performance while offering more flexible layout and lower maintenance costs. Therefore, EMB is now widely used instead of EHB.

[0073] See Figure 3 , Figure 3 A schematic diagram of a braking system provided in an embodiment of this application is shown.

[0074] like Figure 3 As shown, the braking system 120 includes four wheel-end braking devices 127 and a brake controller 128. The brake controller 128 controls the four wheel-end braking devices 127, which brake the four wheels of the electric vehicle respectively, with each wheel-end braking device 127 braking one wheel. Each wheel-end braking device 127 includes a wheel-end controller and a wheel-end actuator (e.g., a brake motor and a brake caliper).

[0075] For each wheel, after the driver operates the brake pedal, the vehicle controller 140 ( Figure 3 (Not shown) sends a braking command (hereinafter referred to as the first braking command) to the brake controller 128. In response to the braking command, the brake controller 128 sends a braking signal to the wheel-end controller of the wheel. The wheel-end controller controls the wheel-end actuator to output braking force to the corresponding brake disc to brake the wheel according to the braking signal. For example, the wheel-end controller controls the brake motor to output torque to drive the brake caliper to clamp the brake disc.

[0076] In this embodiment, each motor controller in the drive system is connected to the vehicle controller, and the brake controller in the braking system is connected to the vehicle controller. This application does not limit the specific communication connection method between the motor controller and the vehicle controller, or between the brake controller and the vehicle controller.

[0077] See Figure 4 , Figure 4 A schematic diagram of a communication architecture for an electric vehicle provided in an embodiment of this application is shown.

[0078] like Figure 4As shown, each motor controller and the vehicle controller communicate via a CAN network. The vehicle controller sends drive commands to each motor controller via the CAN network, and each motor controller sends actual drive commands to the vehicle controller via the CAN network. Similarly, the brake controller in the braking system communicates with the vehicle controller via a CAN network. The vehicle controller sends braking commands to the brake controller via the CAN network, and the brake controller sends actual braking signals to the vehicle controller via the CAN network. This CAN network can be a proprietary CAN or a public CAN.

[0079] The architecture of the embodiments of this application has been described above. The motor controller for implementing redundant braking provided by this application will be described below with reference to specific embodiments.

[0080] The following section introduces a motor controller that implements redundant braking, taking the communication between the motor controller, brake controller, and vehicle controller via a CAN network as an example. The architecture of a motor controller that implements redundant braking is similar when communicating through other networks (such as LIN, automotive Ethernet, FlexRay, etc.), and will not be elaborated here.

[0081] See Figure 5 , Figure 5 A schematic diagram of the structure of a motor controller according to an embodiment of this application is shown. Figure 2 Taking the motor controller 123 shown as an example, other motor controllers are similar to motor controller 123 and will not be described in detail here.

[0082] like Figure 5 As shown, the motor controller 123 includes a motor controller housing 1231 and a motor control motherboard 1232 fixed in the motor controller housing. The motor controller housing 1231 is provided with a first communication interface, which includes a first CAN communication terminal 1233 and a second CAN communication terminal 1234.

[0083] The motor controller 123 is used to control the drive motor 113 to output drive torque or braking torque to drive or brake the electric vehicle according to the instructions of the vehicle controller 140 or the brake controller 128.

[0084] The motor controller housing 1231 is used to fix and protect internal components such as the motor control motherboard 1232, provide dust and water protection, conduct away the heat generated by the internal components, and shield the electromagnetic interference generated inside to prevent external radiation.

[0085] The motor control motherboard 1232 is the main control unit of the motor controller, used for functions such as power management, signal acquisition, power drive, and fault protection.

[0086] The first communication interface is used to enable communication between the motor controller and other external devices. The first CAN communication terminal 1233 and the second CAN communication terminal 1234 are used to enable communication between the motor controller and different devices, respectively.

[0087] See also Figure 5 One end of the first CAN communication terminal 1233 is used to connect to the motor control motherboard 1232, and the other end of the first CAN communication terminal 1233 is used to connect to the vehicle controller 140 through the first CAN communication line 1235.

[0088] Among them, the motor controller 123 receives the drive command output by the vehicle controller 140 according to the opening degree of the accelerator pedal through the first CAN communication line 1235 and controls the drive motor 113 to output drive torque. The direction of the drive torque is the same as the direction of the rotation speed of the drive motor.

[0089] In this way, the motor controller 123 can communicate directly with the vehicle controller 140 through the first CAN communication line 1235. The vehicle controller 140 can control the drive motor 113 to output drive torque based on the driver's intention to operate the accelerator pedal and the electric vehicle's status parameters (such as the status of the power battery, the electric vehicle's operating condition, etc.), and adjust relevant controls based on the information fed back by the motor controller 123 (such as the temperature, actual torque, fault status, etc. of the drive motor 113), thus realizing coordinated control at the vehicle level.

[0090] See also Figure 5 One end of the second CAN communication terminal 1234 is used to connect to the motor control motherboard 1232, and the other end of the second CAN communication terminal 1234 is used to connect to the brake controller 128 through the second CAN communication line 1236.

[0091] Among them, the motor controller 123 receives the braking command output by the brake controller 128 according to the opening of the brake pedal through the second CAN communication line 1236, and controls the drive motor 113 to output braking torque. The direction of the braking torque is opposite to the direction of the rotation speed of the drive motor. The brake controller 128 is used to control the four wheel-end braking devices 127 of the electric vehicle to output braking force to the brake discs of the four wheels to brake the electric vehicle.

[0092] In this way, the motor controller 123 can communicate directly with the brake controller 128 through the second CAN communication line 1236. When the braking system 120 loses its braking ability or its braking ability is insufficient, the brake controller 128 can interact with the motor controller 123 through the second CAN communication line 1236, and the drive motor 113 will output braking torque to fully utilize the drive motor 113 to improve the braking ability of the electric vehicle and realize the redundant braking function of the electric vehicle.

[0093] In one embodiment, see further. Figure 5 The motor controller 123 receives the signal from the brake controller 128 forwarded by the vehicle controller 140 through the first CAN communication line 1235.

[0094] In this way, the motor controller 123 can receive signals from the brake controller 128 through two channels: one is to receive signals directly through the second CAN communication line 1236, and the other is to receive signals forwarded by the vehicle controller 140 through the first CAN communication line 1235. The two can achieve redundancy backup.

[0095] The following will describe in detail the control process of the motor controller 123 when the braking system 120 loses its braking ability or has insufficient braking ability.

[0096] In cases where the braking system 120 loses its braking capability or has insufficient braking capability, it is usually due to the failure of the brake controller 128, i.e., both the main and backup brake controllers 128 fail. If either of them can operate normally, the brake controller 128 is not considered to have failed. For example, the communication interface of the brake controller 128 may be subject to electromagnetic interference or a short circuit, the internal power module may be damaged, or the internal power devices may be damaged. Alternatively, the wheel-end braking device 127 may fail, for example, due to damage to internal components of the drive motor 113, a locked transmission mechanism, the brake caliper's friction pads failing to return to their original position, or a failed wheel-end sensor.

[0097] When brake controller 128 fails, the braking capability of the entire braking system 120 is lost, and both channels between motor controller 123 and brake controller 128 become unusable. When wheel-end brake device 127 fails, only the wheel braked by the failed wheel-end brake device 127 is affected, and motor controller 123 and brake controller 128 can still communicate through the two channels. In summary, failure of brake controller 128 is more serious.

[0098] In one embodiment, the motor controller 123 can determine whether the brake controller 128 or the wheel-end brake device 127 has failed by receiving a safety state signal. The safety state signal can indicate whether the brake controller 128 has failed and the number and location of the failed wheel-end brake device 127 among the four wheel-end brake devices 127.

[0099] Specifically, the motor controller 123 is used to: receive a safety status signal sent by the brake controller 128 via the first CAN communication line 1235 and receive a safety status signal forwarded by the vehicle controller 140 from the brake controller 128 via the second CAN communication line 1236; when no safety status signal is received via both CAN communication lines or when both safety status signals received via both CAN communication lines indicate a fault, it determines that the brake controller 128 has failed or at least one wheel-end braking device 127 has failed.

[0100] Thus, the motor controller 123 receives the safety status signal sent by the brake controller 128 through two channels: first, it receives the safety status signal directly through the second CAN communication line 1236; second, it receives the safety status signal forwarded by the vehicle controller 140 through the first CAN communication line 1235. This dual-channel verification prevents single-point communication failures, i.e., the motor controller 123 falsely triggering the redundant braking function due to a fault indicated by the safety status signal received from either the first CAN communication line 1235 or the second CAN communication line 1236. Furthermore, after determining that it is not a single-point failure, the motor controller 123 can determine, based on the safety status signal, whether the brake controller 128 or the wheel-end brake device 127 has failed, as well as the number and location of the failures. This facilitates precise execution of corresponding control after triggering the redundant braking function.

[0101] In one embodiment, after the brake controller 128 failure is detected for the first time, the failure duration of the brake controller 128 is accumulated by a brake controller 128 survival counter. When the failure duration reaches a set confirmation duration threshold, the brake controller 128 is determined to have failed. After the failure is resolved, the brake controller 128 survival counter is restored.

[0102] See Figure 6 , Figure 6 The diagram shows a timing diagram of a safety state signal and a brake controller survival counter provided in an embodiment of this application.

[0103] Figure 6 (a) shows a scenario where at least one wheel-end braking device 127 fails, such as Figure 6 As shown in (a), at the first time t1, at least one wheel-end braking device 127 fails. After the first time t1, the safety state signal indicates no fault, and after the first time t1, the safety state signal indicates a fault, and the brake controller 128 survival counter does not accumulate the failure duration.

[0104] Figure 6 (b) shows a scenario where the brake controller 128 fails, such as Figure 6As shown in (b), at the first time t1, the brake controller 128 fails. After the first time t1, the safety state signal indicates no fault. After the first time t1, the safety state signal is lost, and the brake controller 128 survival counter begins to accumulate the failure duration. At the second time t2 after the first time t1, the brake controller 128 is determined to have failed.

[0105] When the brake controller 128 fails, in one embodiment, during the process of controlling the drive motor 113 to output drive torque, before the opening of the brake pedal of the electric vehicle begins to increase, the drive motor 113 is controlled to stop outputting drive torque and the drive motor 113 is controlled to output braking torque to decelerate and stop the electric vehicle.

[0106] In this situation, before the opening of the brake pedal of the electric vehicle begins to increase, that is, before the driver operates the brake pedal, without waiting for the driver to operate the brake pedal, the motor controller 123 controls the drive motor 113 to stop outputting drive torque and controls the drive motor 113 to output braking torque to decelerate and stop the electric vehicle, thus ensuring the driving safety of the electric vehicle in the event of failure of the brake controller 128.

[0107] For ease of understanding, see Figure 7 , Figure 7 This illustration shows a timing diagram of a second braking command, the torque output by the drive motor, and the speed of the electric vehicle, according to an embodiment of this application. The second braking command is a command sent by the controller 128 to the motor controller 123, indicating the braking torque required from the drive motor 113.

[0108] like Figure 7 As shown, at the first time t1, the brake controller 128 fails. Before the first time t1, the driving torque output by the drive motor 113, and the braking torque indicated by the second braking command sent by the brake controller 128 to the motor controller, are 0. After the first time t1, the brake controller 128 stops updating the second braking command sent to the motor controller 123.

[0109] After the first moment t1 and before the second moment t2 when the brake controller 128 is determined to have failed, the braking torque indicated by the second braking command is 0, the braking torque output by the drive motor 113 is 0, and the speed of the electric vehicle remains unchanged.

[0110] After the second moment t2, the braking torque indicated by the second braking command is 0, and the drive motor 113 starts to output braking torque to decelerate and stop the electric vehicle.

[0111] In one embodiment, see further. Figure 7The motor controller 123 actively controls the braking torque output by the drive motor 113 to increase from zero, then remain constant, and then decrease back to zero, so as to slow down and stop the electric vehicle while preventing the electric vehicle from accelerating in the opposite direction.

[0112] When the brake controller 128 fails, in one embodiment, the motor controller 123 is specifically used to: during the process of controlling the output braking torque of the drive motor 113, when the opening of the accelerator pedal increases, control the drive motor 113 to continue to output braking torque to decelerate and stop the electric vehicle.

[0113] In the event of a failure of the brake controller 128, the motor controller 123 will also not respond to the driver's intention to operate the accelerator pedal, even if the driver has a strong intention to accelerate the electric vehicle. The motor controller 123 will continue to output braking torque by controlling the drive motor 113 to decelerate and stop the electric vehicle, thus ensuring the driving safety of the electric vehicle in the event of a failure of the brake controller 128.

[0114] In one embodiment, the motor controller 123 is specifically used to: increase the braking torque output of the drive motor 113 as the speed of the electric vehicle increases. This ensures that the vehicle stops within a specified stopping distance or for a specified stopping time, guaranteeing the driving safety of the electric vehicle.

[0115] When the brake controller 128 fails and the driver operates the accelerator pedal, in one embodiment, as the accelerator pedal opening of the electric vehicle increases, the motor controller 123 actively controls the drive motor 113 to stop outputting drive torque and not increase it with the increase of the accelerator pedal opening. Also, when at least one wheel-end brake device 127 fails, the motor controller 123 controls the drive motor 113 to output drive torque, and the drive torque increases with the increase of the accelerator pedal opening.

[0116] As can be seen from the above, the severity of the failure of the brake controller 128 is greater than that of the failure of at least one wheel-end control device, and the risk it poses is greater.

[0117] In this situation, when the driver operates the accelerator pedal, the brake controller 128 fails, the braking ability of the braking system 120 is lost, and the motor controller 123 actively controls the drive motor 113 to stop outputting drive torque and does not increase it with the increase of the accelerator pedal opening. That is, the electric vehicle is not allowed to accelerate, and the electric vehicle is directly controlled to decelerate and stop, so as to ensure the driving safety of the electric vehicle.

[0118] When at least one wheel-end braking device 127 fails, the motor controller 123 actively controls the drive motor 113 to stop outputting drive torque and does not increase it with the increase of the accelerator pedal opening, that is, the electric vehicle is allowed to accelerate. The driver can control the electric vehicle to accelerate or decelerate as desired, ensuring the driving experience.

[0119] For ease of understanding, see Figure 8 , Figure 8 The diagram shows a timing diagram of the opening degree and driving torque of an accelerator pedal according to an embodiment of this application.

[0120] Figure 8 (a) shows a scenario where at least one wheel-end braking device 127 fails, such as Figure 8 As shown in (a), at the first time t1, at least one wheel-end braking device 127 fails; before the first time t1, the opening of the accelerator pedal increases, and the driving torque increases with the increase of the opening of the accelerator pedal; after the first time t1, the opening of the accelerator pedal first increases and then remains constant, and the driving torque first increases and then remains constant with the first increase and then constant opening of the accelerator pedal.

[0121] Figure 8 (b) shows a scenario where the brake controller 128 fails, such as Figure 8 As shown in (b), at the first moment t1, the brake controller 128 fails; before the first moment t1, the opening of the accelerator pedal increases, and the driving torque increases with the increase of the opening of the accelerator pedal; after the first moment t1, the opening of the accelerator pedal first increases and then remains unchanged, stopping the output driving torque.

[0122] When at least one wheel-end braking device 127 fails and the driver operates the accelerator pedal, in one embodiment, the motor controller 123 is configured to: control the drive torque output by the drive motor 113 to increase with the increase of the accelerator pedal opening before the vehicle speed of the electric vehicle accelerates to a vehicle speed threshold; and during the acceleration of the electric vehicle with at least one wheel-end braking device 127 failing, control the drive torque output by the drive motor 113 not to increase with the increase of the accelerator pedal opening when the vehicle speed of the electric vehicle accelerates to the vehicle speed threshold.

[0123] Among them, the speed threshold is the maximum speed at which electric vehicles are allowed to travel.

[0124] Thus, by setting a speed threshold, the maximum speed allowed for the electric vehicle is limited to the braking capacity of the electric vehicle. This allows the electric vehicle to accelerate within a certain speed range during acceleration when at least one wheel-end braking device 127 fails. The motor controller 123 controls the drive torque output by the drive motor 113 to increase with the increase of the accelerator pedal opening, allowing the electric vehicle to accelerate according to the driver's acceleration intention and ensuring a good driving experience. However, when the speed of the electric vehicle exceeds this speed range, the motor controller 123 controls the drive torque output by the drive motor 113 to not increase with the increase of the accelerator pedal opening, preventing the electric vehicle from continuing to accelerate and ensuring the driving safety of the electric vehicle.

[0125] In one embodiment, the motor controller 123 is specifically configured to: when all four wheel-end brake devices 127 are effective and the brake controller 128 is effective, the vehicle speed threshold of the electric vehicle is greater than the vehicle speed threshold when at least one wheel-end brake device 127 fails.

[0126] When all four wheel-end braking devices 127 are effective and the brake controller 128 is effective, the electric vehicle has strong braking capability; when at least one wheel-end braking device 127 fails, the electric vehicle's braking capability is weakened.

[0127] Thus, by actively controlling the electric vehicle's speed threshold to be greater than the speed threshold when all four wheel-end braking devices 127 are effective and the brake controller 128 is effective, the motor controller 123 limits the maximum speed allowed for the electric vehicle to be within the braking capacity range of the electric vehicle, thereby ensuring the driving safety of the electric vehicle.

[0128] The number of failed wheel-end brake devices 127 affects the vehicle speed threshold. Specifically, in one embodiment, the more failed wheel-end brake devices 127, the lower the vehicle speed threshold. The more failed wheel-end brake devices 127, the weaker the braking capability of the electric vehicle. By limiting the vehicle speed threshold to a smaller value, i.e., limiting the maximum speed allowed for the electric vehicle, the maximum speed of the electric vehicle can be limited to within its braking capacity range regardless of its braking capabilities, thereby ensuring the driving safety of the electric vehicle.

[0129] The location of the failed wheel-end brake 127 also affects the speed threshold. Specifically, in one embodiment, the speed threshold of an electric vehicle is lower when two wheel-end brakes 127 on the same side fail (e.g., the wheel-end brakes 127 on both left wheels fail) than when two wheel-end brakes 127 on the same axle fail (e.g., the wheel-end brakes 127 on both front wheels fail).

[0130] If the brake devices 127 on both wheels on the same side fail, the electric vehicle will experience a yaw moment during braking, causing it to veer. The vehicle will veer first, and the driver will have difficulty manually correcting the trajectory, resulting in a very high risk of instability. If the brake devices 127 on both wheels on the same axle fail, the electric vehicle will not veer, and the risk of instability is lower.

[0131] In this case, the speed threshold of the electric vehicle when the two wheel-end braking devices 127 on the same side fail is less than the speed threshold of the electric vehicle when the two wheel-end braking devices 127 on the same axle fail. The greater the risk of instability of the electric vehicle, the smaller the maximum speed limit for the electric vehicle. This ensures that the maximum speed of the electric vehicle can be limited under different instability risks, thereby guaranteeing the driving safety of the electric vehicle.

[0132] When at least one wheel-end braking device 127 fails and the driver operates the brake pedal, in one embodiment, the motor controller 123 is configured to: when the opening of the brake pedal of the electric vehicle begins to increase, control the drive motor 113 to output braking torque according to the braking command, and the braking torque increases as the opening of the brake pedal increases.

[0133] Here, the braking command is the aforementioned second braking command. At this time, the braking capability of the electric vehicle is provided by the braking force output by the effective wheel-end braking device 127 of the braking system 120 and the braking torque output by the drive system 110.

[0134] During the braking process of the electric vehicle, the motor controller 123 receives the second braking command sent by the brake controller 128 through the second CAN communication line 1236, and controls the drive motor 113 to output braking torque. The braking torque increases with the increase of the brake pedal opening, assisting the braking system 120 in braking. This enables the electric vehicle to be braked according to the driver's intention to operate the brake pedal even if at least one wheel-end braking device 127 fails. At the same time, compared with the second braking command forwarded through domain control, the timeliness of receiving the second braking command is improved.

[0135] For ease of understanding, see Figure 9 , Figure 9 This paper illustrates a timing diagram of the opening degree of the accelerator pedal, the opening degree of the brake pedal, the second braking command, the torque output by the drive motor, and the speed of the electric vehicle, according to an embodiment of this application.

[0136] like Figure 9 As shown, at the first time t1, at least one wheel-end braking device 127 fails. Before the first time t1, the accelerator pedal remains constant and then decreases, the drive torque output by the drive motor 113 remains constant and then decreases with the change in the accelerator pedal, the braking torque indicated by the second braking command is 0, and the speed of the electric vehicle remains constant and then decreases. At the second time t2, after the first time t1, the opening of the brake pedal begins to increase.

[0137] After the second moment t2 and before the third moment t3, when the brake pedal opening is 0 and the accelerator pedal opening begins to increase, the brake pedal opening first increases, then remains constant, and then decreases. The braking torque indicated by the second braking command first increases and then decreases with the change of the brake pedal. The braking torque output by the drive motor 113 changes with the change of the braking torque indicated by the second braking command, and the speed of the electric vehicle gradually decreases.

[0138] After the third moment t3 and before the fourth moment t4 when the speed of the electric vehicle decreases to 0, the accelerator pedal first increases and then decreases, and the driving torque output by the drive motor 113 first increases and then decreases with the change of the accelerator pedal, and the speed of the electric vehicle first increases and then decreases to zero.

[0139] When at least one wheel-end braking device 127 fails, in one embodiment, the motor controller 123 is configured to: during the process of controlling the output braking torque of the drive motor 113, when the wheels of the electric vehicle slip, before the opening of the brake pedal begins to decrease, actively control the drive motor 113 to reduce the output braking torque until the wheels no longer slip; after the wheels no longer slip, actively control the drive motor 113 to restore the output braking torque.

[0140] Here, "wheel" refers to the wheel controlled by the motor controller 123.

[0141] When a wheel controlled by the motor controller 123 slips, for example, when the wheel is traveling on a low-friction surface, continuing to output the same amount of braking torque will cause the wheel to lock up or rotate in the opposite direction, thus causing the electric vehicle to become unstable. Therefore, when a wheel controlled by the motor controller 123 slips, the motor controller 123 actively controls the drive motor 113 to reduce the output braking torque before the brake pedal opening begins to decrease, to avoid continuing to output the braking torque and causing the wheel to lock up or rotate in the opposite direction, thus preventing the electric vehicle from becoming unstable. After the wheel stops slipping, the motor controller 123 actively controls the drive motor 113 to restore the output braking torque, promptly restoring the braking torque of the brake motor and ensuring the braking efficiency of the electric vehicle.

[0142] In one embodiment, wheel slippage controlled by motor controller 123 can be identified by the difference between the deceleration of the electric vehicle and the deceleration of the drive motor 113 controlled by motor controller 123 being greater than a first preset difference value, such as -3 m° / s² or -4 m° / s². Wheel slippage relief controlled by motor controller 123 can be identified by the difference between the deceleration of the electric vehicle and the deceleration of the drive motor 113 controlled by motor controller 123 being less than a second preset difference value, such as -0.5 m° / s² or -0.2 m° / s².

[0143] For ease of understanding, see Figure 10 , Figure 10 This diagram illustrates a difference in acceleration and the torque output by a drive system according to an embodiment of this application. The deceleration is an acceleration whose direction is opposite to the direction of motion.

[0144] like Figure 10 As shown, when the difference between the deceleration of the electric vehicle and the deceleration of the drive motor 113 controlled by the motor controller 123 is greater than a first preset difference, the braking torque decreases. When the difference between the deceleration of the electric vehicle and the deceleration of the drive motor 113 controlled by the motor controller 123 decreases to a second preset difference, the braking torque is restored.

[0145] In one embodiment, the motor controller 123 is specifically configured to: The greater the difference between the deceleration of the electric vehicle and the deceleration of the drive motor 113, the greater the reduction in the braking torque output by the drive motor 113. The greater the difference between the deceleration of the electric vehicle and the deceleration of the drive motor 113, the more severe the wheel slippage. In this case, the motor controller 123, by actively controlling the reduction in the braking torque output by the drive motor 113, can prevent the electric vehicle from becoming unstable under varying degrees of wheel slippage by reducing the braking torque output by the drive motor 113.

[0146] Among them, a torque coefficient K1 can be set, and a mapping relationship between the deceleration of the electric vehicle and the difference between the deceleration of the drive motor 113 and the torque coefficient K2 can be established in advance. The larger the difference in deceleration, the larger the torque coefficient K1. The braking torque after torque reduction is obtained by multiplying the braking torque before torque reduction by the torque coefficient K1.

[0147] In one embodiment, during the process of controlling the output drive torque of the drive motor, the motor controller 123 is configured to: when the wheels of the electric vehicle slip, before the opening of the accelerator pedal begins to decrease, actively control the drive motor 113 to reduce the output drive torque until the wheels no longer slip; and after the wheels no longer slip, actively control the drive motor 113 to restore the output drive torque.

[0148] When a wheel controlled by the motor controller 123 slips, for example, when the wheel is traveling on a low-friction surface, continuing to output the same amount of drive torque will cause the wheel to excessively slip, thus causing the electric vehicle to become unstable. Therefore, when a wheel controlled by the motor controller 123 slips, the motor controller 123 actively controls the drive motor 113 to reduce the output drive torque before the accelerator pedal opening begins to decrease, to avoid continuing to output drive torque and causing the wheel to excessively slip and thus become unstable. After the wheel stops slipping, the motor controller 123 actively controls the drive motor 113 to restore the output drive torque, promptly restoring the drive torque of the brake motor and ensuring the driving efficiency of the electric vehicle.

[0149] Similarly, in one embodiment, wheel slippage controlled by motor controller 123 can be identified by the difference between the acceleration of drive motor 113 controlled by motor controller 123 and the acceleration of electric vehicle being greater than a third preset difference value, such as 3 m° / s², 4 m° / s², etc.; wheel slippage relief controlled by motor controller 123 can be identified by the difference between the acceleration of drive motor 113 controlled by motor controller 123 and the acceleration of electric vehicle being less than a fourth preset difference value, such as 0.5 m° / s², 0.2 m° / s², etc.

[0150] See also Figure 10 ,like Figure 10 As shown, when the difference between the acceleration of the drive motor 113 controlled by the motor controller 123 and the acceleration of the electric vehicle is greater than the third preset difference, the drive torque decreases. When the difference between the acceleration of the drive motor 113 controlled by the motor controller 123 and the acceleration of the electric vehicle decreases to the fourth preset difference, the drive torque is restored.

[0151] In one embodiment, the motor controller 123 is specifically configured to: The greater the difference between the acceleration of the drive motor 113 and the acceleration of the electric vehicle, the greater the reduction in the driving torque output by the drive motor 113. The greater the difference between the acceleration of the electric vehicle and the acceleration of the drive motor 113, the more severe the wheel slippage. In this case, the motor controller 123, by actively controlling the reduction in the braking torque output by the drive motor 113, can prevent the electric vehicle from becoming unstable by reducing the driving torque output by the drive motor 113 under varying degrees of wheel slippage.

[0152] Among them, a torque coefficient K2 can be set, and a mapping relationship between the difference between the acceleration of the drive motor 113 controlled by the motor controller 123 and the acceleration of the electric vehicle and the torque coefficient K2 can be established in advance. The larger the difference in acceleration, the larger the torque coefficient K2. The drive torque after torque reduction is obtained by multiplying the torque coefficient K2 by the drive torque before torque reduction.

[0153] When at least one wheel-end braking device 127 fails, in one embodiment, during the process of controlling the output braking torque of the drive motor, when the difference between the first yaw rate from the inertial measurement unit and the second yaw rate calculated based on the wheel speeds of the four wheels is greater than the first difference, the motor controller 123 actively controls the drive motor 113 to reduce the output braking torque; when the difference between the first yaw rate and the second yaw rate decreases to less than the second difference, the motor controller 123 actively controls the drive motor 113 to restore the output braking torque.

[0154] Among them, the first yaw rate is the actual value of the yaw rate, and the second yaw rate is the calculated value of the yaw rate.

[0155] When the difference between the first yaw rate and the second yaw rate is greater than the first difference, for example, when an electric vehicle is traveling on a split road, it indicates that the yaw rate of the electric vehicle deviates from the expected value. Continuing to output the braking torque will cause the electric vehicle to lose directional stability. The first difference is, for example, 5° / s, 6° / s, etc. When the difference between the first yaw rate and the second yaw rate decreases to less than the second difference, it indicates that the directional stability of the electric vehicle is relatively high. The second difference is, for example, 1° / s, 1.5° / s, etc.

[0156] Thus, when the electric vehicle loses directional stability, the motor controller 123 actively controls the drive motor 113 to reduce the output braking torque to avoid the electric vehicle from losing stability due to continued output of braking torque. After the electric vehicle has achieved greater directional stability, the motor controller 123 actively controls the drive motor 113 to restore the output braking torque, thereby timely restoring the braking torque of the brake motor and ensuring the braking efficiency of the electric vehicle.

[0157] In one embodiment, the second yaw rate can be calculated based on the wheel speeds of the four wheels using the Ackermann steering geometry principle. The second yaw rate = (left wheel speed - right wheel speed) × wheel track / 2.

[0158] For ease of understanding, see Figure 11 , Figure 11 This diagram illustrates the difference in yaw rate and the output torque of the drive motor according to an embodiment of this application.

[0159] like Figure 11 As shown, when the difference between the first yaw rate and the second yaw rate is greater than the first difference, the braking torque decreases; when the difference between the first yaw rate and the second yaw rate decreases to the second difference, the braking torque recovers.

[0160] In one embodiment, during the process of controlling the output drive torque of the drive motor, when the difference between the first yaw rate and the second yaw rate is greater than the first difference, the motor controller 123 actively controls the drive motor 113 to reduce the output drive torque; when the difference between the first yaw rate and the second yaw rate decreases to less than the second difference, the motor controller 123 actively controls the drive motor 113 to restore the output drive torque.

[0161] Thus, when the electric vehicle loses directional stability, the motor controller 123 actively controls the drive motor 113 to reduce the output drive torque to avoid the electric vehicle from losing stability due to continued output of drive torque. After the electric vehicle has achieved a certain level of directional stability, the motor controller 123 actively controls the drive motor 113 to restore the output drive torque, thereby timely restoring the drive torque of the drive motor 113 and ensuring the driving efficiency of the electric vehicle.

[0162] See also Figure 11 When the difference between the first yaw rate and the second yaw rate is greater than the first difference, the driving torque decreases; when the difference between the first yaw rate and the second yaw rate decreases to the second difference, the driving torque recovers.

[0163] In one embodiment, the greater the difference between the first yaw rate and the second yaw rate, the greater the reduction in the driving torque or braking torque output by the drive motor 113 actively controlled by the motor controller 123. This ensures that, under varying degrees of instability in the electric vehicle, instability can be prevented by reducing the driving torque or braking torque output by the drive motor 113.

[0164] Among them, a torque coefficient K3 can be set, and a mapping relationship between the difference between the first yaw rate and the second yaw rate and the torque coefficient K3 can be established in advance. The larger the difference between the first yaw rate and the second yaw rate, the larger the torque coefficient K3. The reduced torque or braking torque can be obtained by multiplying the torque coefficient K3 by the driving torque or braking torque before torque reduction.

[0165] In one embodiment, the reduced drive torque or braking torque can be calculated based on at least one of K1, K2 and K3.

[0166] During the straight-line movement of the electric vehicle, the calculated value of the yaw rate can be disregarded. Instead, the control of the torque output by the drive motor 113 can be determined directly by comparing the actual value of the yaw rate with a preset yaw rate. Specifically, in one embodiment, during the process of controlling the output braking torque of the drive motor, before the steering wheel of the electric vehicle begins to turn, if the yaw rate of the electric vehicle is greater than a first preset yaw rate, the motor controller 123 actively controls the drive motor 113 to reduce the output braking torque; when the yaw rate decreases to less than a second preset yaw rate, the motor controller 123 actively controls the drive motor 113 to restore the output braking torque.

[0167] Before the steering wheel begins to turn, it indicates that the electric vehicle is maintaining a straight-line driving state. In one embodiment, the electric vehicle is allowed to make minor adjustments to the steering wheel while driving straight, and related controls can be performed before the steering wheel angle of the electric vehicle exceeds a preset angle.

[0168] Here, "the yaw rate of the electric vehicle is greater than the preset yaw rate" refers to the actual value of the aforementioned yaw rate.

[0169] If the yaw rate of the electric vehicle is greater than the first preset yaw rate, it indicates that the yaw rate of the electric vehicle deviates from the expected value, and continuing to output the braking torque will cause the electric vehicle to lose directional stability. When the yaw rate decreases to the second preset yaw rate, it indicates that the directional stability of the electric vehicle is relatively high.

[0170] Thus, when the electric vehicle loses directional stability, the motor controller 123 actively controls the drive motor 113 to reduce the output braking torque to avoid the electric vehicle from losing stability due to continued output of braking torque. After the electric vehicle has achieved greater directional stability, the motor controller 123 actively controls the drive motor 113 to restore the output braking torque, thereby timely restoring the braking torque of the brake motor and ensuring the braking efficiency of the electric vehicle.

[0171] In one embodiment, during the process of controlling the output drive torque of the drive motor, before the steering wheel of the electric vehicle starts to turn, when the yaw rate of the electric vehicle is greater than a first preset yaw rate, the motor controller 123 actively controls the drive motor 113 to reduce the output drive torque; when the yaw rate is reduced to a second preset yaw rate, the motor controller 123 actively controls the drive motor 113 to restore the output drive torque.

[0172] Thus, when the electric vehicle loses directional stability, the motor controller 123 actively controls the drive motor 113 to reduce the output drive torque to avoid the electric vehicle from losing stability due to continued output of drive torque. After the electric vehicle has achieved a certain level of directional stability, the motor controller 123 actively controls the drive motor 113 to restore the output drive torque, thereby timely restoring the drive torque of the drive motor 113 and ensuring the driving efficiency of the electric vehicle.

[0173] In one embodiment, the greater the yaw rate of the electric vehicle, the greater the reduction in the driving torque or braking torque output by the drive motor 113 actively controlled by the motor controller 123. This ensures that the electric vehicle can avoid instability by reducing the driving torque or braking torque output by the drive motor 113 under varying degrees of instability.

[0174] It is understood that the brake controller 128 and the four wheel-end brake devices 127 are powered by a low-voltage power supply system. When the low-voltage power supply system of the electric vehicle fails, the drive system 110 of the electric vehicle can be powered by a high-voltage power supply system, and the braking capability of the brake system 120 will be lost. Thus, in one embodiment, before the opening of the brake pedal of the electric vehicle begins to increase, the motor controller 123 actively controls the drive motor 113 to output braking torque to decelerate and stop the electric vehicle; after the opening of the accelerator pedal of the electric vehicle begins to increase, the motor controller 123 actively controls the drive motor 113 to stop outputting driving torque and not increase it with the increase of the opening of the accelerator pedal.

[0175] In this embodiment, when the low-voltage power supply system of the electric vehicle fails, before the brake pedal opening begins to increase (i.e., before the driver operates the brake pedal), the motor controller 123 actively controls the drive motor 113 to output braking torque to decelerate and stop the electric vehicle without waiting for a response from the driver to operate the brake pedal, thus improving the driving safety of the electric vehicle. Furthermore, after the accelerator pedal opening begins to increase, the motor controller 123 actively controls the drive motor 113 to stop outputting driving torque and prevents it from increasing with the accelerator pedal opening; that is, it does not allow the electric vehicle to accelerate and directly controls the electric vehicle to decelerate and stop, ensuring the driving safety of the electric vehicle.

[0176] When the low-voltage power supply system of an electric vehicle fails, the inertial measurement unit (IMU) will also fail, making it impossible to acquire IMU signals and decode the deceleration of the electric vehicle. At this time, the resolver sensor in the drive system 110 is operating normally.

[0177] Thus, in one embodiment, the motor controller 123 is specifically used to: during the process of controlling the output braking torque of the drive motor 113, when the deceleration of the drive motor 113 is greater than a first preset deceleration, actively control the drive motor 113 to reduce the output braking torque before the opening of the brake pedal begins to decrease; when the deceleration of the drive motor 113 decreases to less than a second preset deceleration, actively control the drive motor 113 to restore the output braking torque.

[0178] If the deceleration of the drive motor 113 is greater than the first preset deceleration, it indicates a higher risk of wheel lock-up or reverse acceleration in the electric vehicle. If the deceleration of the drive motor 113 is less than the second preset deceleration, it indicates lower braking efficiency of the electric vehicle.

[0179] In situations where there is a high risk of wheel lock-up or reverse acceleration in an electric vehicle, the motor controller 123 actively controls the drive motor 113 to reduce the output braking torque before the brake pedal opening begins to decrease, thereby reducing the deceleration of the drive motor 113. When the deceleration of the drive motor decreases to a point where the braking efficiency of the electric vehicle is low, the motor controller 123 actively controls the drive motor 113 to restore the output braking torque, thereby restoring the braking torque in a timely manner and ensuring the braking efficiency of the electric vehicle.

[0180] For ease of understanding, see Figure 12 , Figure 12 A schematic diagram of acceleration and braking torque provided in an embodiment of this application is shown.

[0181] like Figure 12 As shown, when the deceleration of the drive motor 113 is greater than the first preset deceleration, the braking torque decreases. When the braking torque decreases, the deceleration of the drive motor 113 decreases to the second preset deceleration, and the braking torque is restored.

[0182] In one embodiment, the motor controller 123 is configured to: increase the deceleration of the drive motor 113 by actively reducing the braking torque output of the drive motor 113. This ensures that the deceleration of the drive motor can be reduced by actively decreasing the braking torque under different deceleration conditions, thus preventing wheel lock-up or reverse acceleration of the electric vehicle.

[0183] Among them, a torque coefficient K4 can be set, and a mapping relationship between the deceleration of the drive motor 113 and the torque coefficient K4 can be established in advance. The larger the deceleration, the larger the torque coefficient K4. The braking torque after torque reduction is obtained by multiplying the braking torque before torque reduction by the torque coefficient K4.

[0184] In one embodiment, if the IMU failure is not due to a failure of the low-voltage power supply system, K4 can replace K1 in calculating the reduced braking torque.

[0185] In another embodiment of this application, a braking system 120 is also provided. See also Figure 13 , Figure 13 A schematic diagram of a braking system provided in an embodiment of this application is shown.

[0186] like Figure 13 As shown, the braking system 120 includes four wheel-end braking devices 127 and a brake controller 128. The brake controller 128 includes a brake controller housing 1281 and a brake control main board 1282 fixed in the brake controller housing 1281. The brake controller housing 1281 is provided with a second communication interface, which includes a third CAN communication terminal 1283 and a fourth CAN communication terminal 1284.

[0187] The brake controller 128 is used to receive braking commands from the vehicle controller 140 via the brake control main board 1282 and control the four wheel-end braking devices 127 to output braking force to the brake discs of the four wheels to brake the electric vehicle.

[0188] The brake controller housing 1281 is used to fix and protect internal components such as the brake control motherboard 1282, provide dust and water protection, conduct away the heat generated by the internal components, and shield the electromagnetic interference generated inside to prevent external radiation.

[0189] The brake control motherboard 1282 is the main control unit of the brake system 120, used for power management, signal acquisition, brake control, fault protection and other functions.

[0190] The second communication interface is used to enable the brake controller 128 to communicate with other external devices, and the third CAN communication terminal 1283 and the fourth CAN communication terminal 1284 are used to enable the brake controller 128 to communicate with different devices.

[0191] See also Figure 13 One end of the third CAN communication terminal 1283 is used to connect to the brake control main board 1282, and the other end of the third CAN communication terminal 1283 is used to connect to the vehicle controller 140 through the third CAN communication line 1285. One end of the fourth CAN communication terminal 1284 is used to connect to the brake control main board 1282, and the other end of the fourth CAN communication terminal 1284 is used to connect to the motor controller 123 (taking the motor controller 123 as an example) through the second CAN communication line 1236.

[0192] In this way, the brake controller 128 can communicate directly with the vehicle controller 140 through the third CAN communication line 1285. The vehicle controller 140 can control the braking system 120 to output braking force based on the driver's intention and the electric vehicle's status parameters (such as the status of the power battery, the operating condition of the electric vehicle, etc.), and adjust relevant controls based on the information fed back by the brake controller 128 (such as actual braking force, fault status, etc.), thus realizing coordinated control at the vehicle level.

[0193] The brake controller 128 can also communicate directly with the motor controller 123 via the second CAN communication line 1236. When the braking system 120 loses its braking ability or its braking ability is insufficient, the brake controller 128 can interact with the motor controller 123 via the second CAN communication line 1236, and the drive motor 113 will cooperate to perform braking, making full use of the drive motor 113 to improve the braking ability of the electric vehicle and realize the redundant braking function of the electric vehicle.

[0194] See also Figure 13 The second communication interface also includes a wheel-end CAN communication terminal 1286. One end of the wheel-end CAN communication terminal 1286 is used to connect to the brake control main board 1282, and the other end of the wheel-end CAN communication terminal 1286 is used to connect to the wheel-end braking device 127 through the fourth CAN communication line 1287. In this way, communication between the brake controller 128 and the wheel-end braking device 127 is realized, so that the brake controller 128 can control the wheel-end braking device 127 to output braking force.

[0195] See Figure 14 , Figure 14 A schematic diagram of a system architecture for implementing redundant braking function provided in an embodiment of this application is shown.

[0196] like Figure 14As shown, when the driver operates the brake pedal, the vehicle controller 140 sends a first braking command to the brake controller 128. When at least one wheel-end brake device 127 fails, the brake controller 128 outputs a braking signal to the wheel-end brake device 127 to control the non-failed wheel-end brake device 127 to output braking force, and at the same time sends a second braking command to the motor controller 123.

[0197] The motor controller 123 operates in torque open-loop mode and speed closed-loop mode. After receiving the second braking command, it receives the IMU signal from the inertial measurement unit (IMU) and decodes the IMU signal to obtain the acceleration of the electric vehicle. It also decodes the resolver signal from the resolver sensor to obtain the speed and acceleration of the drive motor 113. Then, based on the yaw rate and the acceleration of the drive motor 113, it calculates the torque coefficient and controls the corresponding drive motor 113 to output braking torque according to the braking torque indicated by the second braking command and the torque coefficient. During this process, the speed of the electric vehicle is calculated based on the speed of the drive motor 113, and the vehicle speed is limited within a speed threshold.

[0198] For further descriptions of the brake controller 128 in the redundant braking function, please refer to the relevant descriptions in the motor controller 123, which will not be repeated here.

[0199] In another embodiment of this application, an electric vehicle is also provided. See also Figure 15 , Figure 15 A schematic diagram of a communication architecture for an electric vehicle provided in an embodiment of this application is shown.

[0200] like Figure 15As shown, the electric vehicle includes a drive system 110, a braking system 120, and a vehicle controller 140. The drive system 110 includes at least one drive motor 113 and at least one motor controller 123. Each motor controller 123 includes a motor controller housing 1231 and a motor control motherboard 1232 fixed in the motor controller housing 1231. The at least one motor controller 123 is used to control the at least one drive motor 113 to output drive torque or braking torque to drive or brake the electric vehicle according to the drive command of the vehicle controller 140. Each motor controller housing 1231 is provided with a first communication interface, which includes a first CAN communication terminal 1233. The braking system 120 includes four wheel-end braking devices 127 and a brake controller 128. The brake controller 128 includes a brake controller housing 1281 and a brake control main board 1282 fixed in the brake controller housing 1281. The brake controller 128 is used to brake the electric vehicle by controlling the four wheel-end braking devices 127 to output braking force to the brake discs of the four wheels according to the braking command of the vehicle controller 140. The brake controller housing 1281 is provided with a second communication interface, which includes a third CAN communication terminal 1283, a fourth CAN communication terminal 1284 and a wheel-end CAN communication terminal 1286.

[0201] See also Figure 15 One end of the first CAN communication terminal 1233 is used to connect to the motor control main board 1232, and the other end of the first CAN communication terminal 1233 is used to connect to the vehicle controller 140 via the first CAN communication line 1235. One end of the second CAN communication terminal 1234 is used to connect to the motor control main board 1232, and the other end of the second CAN communication terminal 1234 is used to connect to one end of the fourth CAN communication terminal 1284 via the second CAN communication line 1236. The other end of the fourth CAN communication terminal 1284 is used to connect to the brake control main board 1282. The third CAN communication terminal 128... One end of the third CAN communication terminal 1283 is used to connect to the brake control main board 1282. The other end of the third CAN communication terminal 1283 is used to connect to the vehicle controller 140 through the third CAN communication line 1285. One end of the wheel end CAN communication terminal 1286 is used to connect to the brake control main board 1282. The other end of the wheel end CAN communication terminal 1286 is used to connect to the wheel end brake device 127 through the fourth CAN communication line 1287. The brake controller 128 is also used to control the four wheel end brake devices 127 of the electric vehicle to output braking force to the brake discs of the four wheels to brake the electric vehicle through the fourth CAN communication line 1287.

[0202] It is understood that all relevant content of each step involved in the above method embodiments can be referenced in the embodiments of the braking system and the electric vehicle, and will not be repeated here.

[0203] Finally, it should be noted that the above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A motor controller for implementing redundant braking, characterized in that, The motor controller includes a motor controller housing and a motor control main board fixed in the motor controller housing. The motor controller is used to control the drive motor to output drive torque or braking torque to drive or brake the electric vehicle according to the instructions of the vehicle controller or brake controller. The motor controller housing is provided with a first communication interface, which includes a first CAN communication terminal and a second CAN communication terminal, wherein: One end of the first CAN communication terminal is used to connect to the motor control motherboard, and the other end of the first CAN communication terminal is used to connect to the vehicle controller through the first CAN communication line. The motor controller receives the drive command output by the vehicle controller according to the opening degree of the accelerator pedal through the first CAN communication line and controls the drive motor to output drive torque. The direction of the drive torque is the same as the rotational speed direction of the drive motor. One end of the second CAN communication terminal is used to connect to the motor control motherboard, and the other end of the second CAN communication terminal is used to connect to the brake controller through the second CAN communication line. The motor controller receives the braking command output by the brake controller according to the opening of the brake pedal through the second CAN communication line and controls the drive motor to output braking torque. The direction of the braking torque is opposite to the rotational speed direction of the drive motor. The brake controller is also used to control the four wheel-end braking devices of the electric vehicle to output braking force to the brake discs of the four wheels to brake the electric vehicle.

2. The motor controller according to claim 1, characterized in that, The motor controller is used for: During braking when at least one of the four wheel-end braking devices fails, when the opening of the brake pedal of the electric vehicle begins to increase, the drive motor is controlled to output the braking torque according to the braking command, and the braking torque increases as the opening of the brake pedal increases.

3. The motor controller according to claim 1, characterized in that, The motor controller is used for: If the brake controller fails during the process of controlling the output drive torque of the drive motor, before the opening of the brake pedal of the electric vehicle begins to increase, the drive motor is controlled to stop outputting the drive torque and the brake torque is controlled to be output by the drive motor to decelerate and stop the electric vehicle.

4. The motor controller according to claim 3, characterized in that, The motor controller is specifically used for: During the process of controlling the drive motor to output the braking torque, when the opening of the accelerator pedal increases, the drive motor is controlled to continue outputting the braking torque to decelerate and stop the electric vehicle.

5. The motor controller according to claim 2 or 3, characterized in that, The motor controller is used for: The system receives a safety status signal sent by the brake controller through the first CAN communication line and a safety status signal forwarded by the vehicle controller from the brake controller through the second CAN communication line. If the safety status signal is not received through both CAN communication lines, or if the safety status signal received through both CAN communication lines indicates a fault, it is determined that the brake controller has failed or at least one of the wheel-end brake devices has failed.

6. The motor controller according to claim 1, characterized in that, The motor controller is used for When at least one of the wheel-end braking devices fails, during the process of increasing the opening of the accelerator pedal of the electric vehicle, the drive motor is controlled to output drive torque, and the drive torque increases as the opening of the accelerator pedal increases. When the brake controller fails, the active control drive motor stops outputting drive torque and does not increase with the increase of the accelerator pedal opening.

7. The motor controller according to claim 6, characterized in that, The motor controller is used for: During the acceleration of an electric vehicle in which at least one of the wheel-end braking devices fails, before the vehicle speed accelerates to a speed threshold, the drive torque output by the control drive motor increases with the increase of the accelerator pedal opening. During the acceleration of an electric vehicle in which at least one of the wheel-end braking devices fails, when the vehicle speed accelerates to a vehicle speed threshold, the drive torque output by the control drive motor does not increase with the increase of the accelerator pedal opening.

8. The motor controller according to claim 6, characterized in that, The speed threshold of the electric vehicle is greater than the speed threshold when all four wheel-end braking devices are effective and the brake controller is effective, which is the case when at least one of the wheel-end braking devices fails.

9. The motor controller according to claim 6, characterized in that, The speed threshold of the electric vehicle is less than the speed threshold when both wheel-end brake devices on the same side fail.

10. The motor controller according to claim 2, characterized in that, The motor controller is used for: During the process of controlling the output braking torque of the drive motor, when the wheels of the electric vehicle slip, before the opening of the brake pedal begins to decrease, the drive motor is actively controlled to reduce the output braking torque until the wheels no longer slip. After the wheels stop slipping, the drive motor is actively controlled to resume output braking torque.

11. The motor controller according to claim 2, characterized in that, The motor controller is used for: During the process of controlling the output braking torque of the drive motor, when the electric vehicle is traveling straight and before the steering wheel of the electric vehicle starts to turn, if the yaw rate of the electric vehicle is greater than the first preset yaw rate, the drive motor is actively controlled to reduce the output braking torque. When the yaw rate decreases to less than the second preset yaw rate, the drive motor is actively controlled to restore the output braking torque.

12. The motor controller according to claim 2 or 3, characterized in that, The motor controller is specifically used for: During the process of controlling the output braking torque of the drive motor, when the deceleration of the drive motor is greater than the first preset deceleration, the drive motor is actively controlled to reduce the output braking torque before the opening of the brake pedal of the electric vehicle begins to decrease. When the deceleration of the drive motor decreases to less than the second preset deceleration, the drive motor is actively controlled to resume output braking torque.

13. The motor controller according to claim 2, characterized in that, The motor controller is used for: The greater the difference between the deceleration of the electric vehicle and the deceleration of the drive motor, the greater the reduction in the braking torque output by the actively controlled drive motor.

14. A braking system, characterized in that, The braking system includes four wheel-end braking devices and a brake controller. The brake controller includes a brake controller housing and a brake control main board fixed in the brake controller housing. The brake controller is used to control the four wheel-end braking devices to output braking force to the brake discs of the four wheels to brake the electric vehicle according to the braking command of the vehicle controller. The brake controller housing is provided with a second communication interface, which includes a third CAN communication terminal, a fourth CAN communication terminal, and wheel-end CAN communication terminals, wherein: One end of the third CAN communication terminal is used to connect to the brake control motherboard, and the other end of the third CAN communication terminal is used to connect to the vehicle controller through the third CAN communication line. One end of the fourth CAN communication terminal is used to connect to the brake control motherboard, and the other end of the fourth CAN communication terminal is used to connect to the motor controller through the second CAN communication line. The motor controller is used to control the drive motor to output drive torque or braking torque to drive or brake the electric vehicle according to the instructions of the vehicle controller or the brake controller. One end of the wheel-end CAN communication terminal is used to connect to the brake control main board, and the other end of the wheel-end CAN communication terminal is used to connect to the wheel-end braking device through the fourth CAN communication line. The brake controller is also used to control the four wheel-end braking devices of the electric vehicle to output braking force to the brake discs of the four wheels to brake the electric vehicle through the fourth CAN communication line.

15. An electric vehicle, characterized in that, The electric vehicle includes a drive system, a braking system, and a vehicle controller. The drive system includes at least one drive motor and at least one motor controller. Each motor controller includes a motor controller housing and a motor control motherboard fixed in the motor controller housing. The at least one motor controller is used to control the at least one drive motor to output drive torque or braking torque to drive or brake the electric vehicle according to the instructions of the vehicle controller or the braking controller. Each motor controller housing is provided with a first communication interface, which includes a first CAN communication terminal and a second CAN communication terminal. The braking system includes four wheel-end braking devices and a brake controller. The brake controller includes a brake controller housing and a brake control motherboard fixed in the brake controller housing. The brake controller is used to control the four wheel-end braking devices to output braking force to the brake discs of the four wheels to brake the electric vehicle according to the braking instructions of the vehicle controller. The brake controller housing is provided with a second communication interface, which includes a third CAN communication terminal, a fourth CAN communication terminal, and wheel-end CAN communication terminals, wherein: One end of the first CAN communication terminal is used to connect to the motor control main board, and the other end of the first CAN communication terminal is used to connect to the vehicle controller via the first CAN communication line. One end of the second CAN communication terminal is used to connect to the motor control main board, and the other end of the second CAN communication terminal is used to connect to one end of the third CAN communication terminal via the second CAN communication line. The other end of the third CAN communication terminal is used to connect to the brake control main board, and one end of the fourth CAN communication terminal is used to connect to the vehicle controller via the third CAN communication line. One end of the wheel-end CAN communication terminal is used to connect to the brake control main board, and the other end of the wheel-end CAN communication terminal is used to connect to the wheel-end braking device via the fourth CAN communication line. The brake controller is also used to control the four wheel-end braking devices of the electric vehicle to output braking force to the brake discs of the four wheels to brake the electric vehicle via the fourth CAN communication line.

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