Fault handling method and device for vehicle electric drive system and vehicle

Abstract

The present invention discloses a fault handling method, device, and vehicle for a vehicle electric drive system. The method comprises: in response to a preset fault signal of the vehicle electric drive system, controlling a motor controller of the vehicle electric drive system to switch from a normal mode to a safe mode, wherein the safe mode prohibits the vehicle controller from issuing control instructions to the motor controller; after the motor controller enters the safe mode, if preset conditions are met, adjusting a software control program for controlling the motor controller to allow the vehicle controller to issue control instructions to the motor controller; and if a target control instruction is issued to the motor controller after the software control program is adjusted, controlling the motor controller to execute the target control instruction according to a safety response strategy. The present invention solves the technical problem of low vehicle driving safety.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle control technology, and in particular relates to a method and device for troubleshooting a vehicle electric drive system, and a vehicle. Background Art

[0002] The vehicle's electric drive system is one of the core systems of new energy vehicles. Due to the complexity of the working environment, failures in the vehicle's electric drive system often occur. Such failures will cause the motor controller of the vehicle's electric drive system to switch from normal mode to safety mode. When the motor controller is in safety mode, the vehicle may break down or have reduced power, which may lead to rear-end collisions and low vehicle driving safety. Summary of the Invention

[0003] The embodiments of the present invention provide a method and device for troubleshooting a vehicle electric drive system, and a vehicle, which solve the technical problem of low driving safety of the vehicle.

[0004] In a first aspect, an embodiment of the present invention provides a fault handling method for a vehicle electric drive system, comprising: in response to a preset fault signal of the vehicle electric drive system, controlling the motor controller of the vehicle electric drive system to switch from a normal mode to a safe mode, wherein the safe mode is a mode that prohibits the vehicle controller from issuing control instructions to the motor controller; after the motor controller enters the safe mode, if preset conditions are met, adjusting the software control program for controlling the motor controller to allow the vehicle controller to issue control instructions to the motor controller; if a target control instruction is issued to the motor controller after the software control program is adjusted, controlling the motor controller to execute the target control instruction in accordance with a safety response strategy.

[0005] In conjunction with the first aspect of the present invention, in some embodiments, adjusting the software control program for controlling the motor controller includes: resetting a fault state of the vehicle electric drive system in the software control program.

[0006] In conjunction with the first aspect of the present invention, in some implementations, a command response speed in the safe mode is lower than a command response speed in the normal mode.

[0007] In combination with the first aspect of the present invention, in some embodiments, the target control instruction is a torque request instruction, and the controlling the motor controller to execute the target control instruction in accordance with the safety response strategy includes: controlling the motor controller to switch from the safety mode to the normal mode; within a first time period after the motor controller switches to the normal mode, controlling the output torque of the motor to be maintained at a preset torque through the motor controller; within a second time period after the first time period, controlling the output torque of the motor to gradually increase from the preset torque to the target torque indicated by the torque request instruction through the motor controller.

[0008] In combination with the first aspect of the present invention, in some embodiments, the safety mode is an FW mode, and controlling the output torque of the motor to maintain at a preset torque through the motor controller includes: performing closed-loop control of the output torque of the motor through the motor controller to maintain the output torque of the motor at the preset torque.

[0009] In combination with the first aspect of the present invention, in some embodiments, the safety mode is an ASC mode, and the controlling of the output torque of the motor by the motor controller to maintain the preset torque includes: performing a first open-loop control on the dq axis voltage of the motor by the motor controller to put the motor controller in an active short-circuit state; after the motor controller is in the active short-circuit state, performing a second open-loop control on the dq axis voltage of the motor by the motor controller to make the dq axis weak magnetic voltage of the motor offset the induced back electromotive force of the motor; after the dq axis weak magnetic voltage of the motor offsets the induced back electromotive force of the motor, performing closed-loop control on the output torque of the motor by the motor controller to maintain the output torque of the motor at the preset torque.

[0010] In combination with the first aspect of the present invention, in some embodiments, controlling the output torque of the motor to gradually increase from the preset torque to the target torque indicated by the torque request instruction through the motor controller includes: controlling the output torque of the motor to gradually increase from the preset torque to the target torque indicated by the torque request instruction according to a linear increasing trend through the motor controller; or controlling the output torque of the motor to gradually increase from the preset torque to the target torque indicated by the torque request instruction according to a nonlinear increasing trend through the motor controller.

[0011] In combination with the first aspect of the present invention, in some embodiments, the preset conditions include: the time duration for the motor controller to execute the target control instruction is less than a preset time threshold, and the number of times the motor controller executes the target control instruction is less than a preset number threshold.

[0012] In a second aspect, an embodiment of the present invention provides a fault handling device for a vehicle electric drive system, comprising: a switching unit for controlling the motor controller of the vehicle electric drive system to switch from a normal mode to a safe mode in response to a preset fault signal of the vehicle electric drive system, wherein the safe mode is a mode that prohibits the vehicle controller from issuing control instructions to the motor controller; an adjustment unit for adjusting the software control program for controlling the motor controller after the motor controller enters the safe mode if preset conditions are met, so as to allow the vehicle controller to issue control instructions to the motor controller; and an execution unit for controlling the motor controller to execute the target control instruction in accordance with a safety response strategy if a target control instruction is issued to the motor controller after adjusting the software control program.

[0013] In a third aspect, an embodiment of the present invention provides a vehicle comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method described in any one of the first aspects is implemented.

[0014] The one or more technical solutions provided by the embodiments of the present invention achieve at least the following technical effects or advantages:

[0015] The embodiment of the present invention controls the motor controller of the vehicle electric drive system to switch from normal mode to safe mode in response to a preset fault signal of the vehicle electric drive system. The safe mode is a mode that prohibits the vehicle controller from sending control instructions to the motor controller. After the motor controller enters the safe mode, if the preset conditions are met, the software control program for controlling the motor controller is adjusted to allow the vehicle controller to send control instructions to the motor controller. If the target control instruction is sent to the motor controller after the software control program is adjusted, the motor controller is controlled to execute the target control instruction according to the safety response strategy. After the software control program is adjusted, the vehicle controller is allowed to send control instructions to the motor controller. If the target control instruction is sent to the motor controller, the motor controller is controlled to execute the target control instruction according to the safety response strategy. The motor controller can control the motor according to the target control instruction, thereby avoiding the problem of the vehicle breaking down or the power being weakened, and thus avoiding the occurrence of vehicle rear-end collisions. Therefore, the driving safety of the vehicle is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 Flowchart of a method for troubleshooting a vehicle electric drive system according to an embodiment of the present invention;

[0018] Figure 2 Schematic diagram of a linear increase trend and a nonlinear increase trend in an embodiment of the present invention;

[0019] Figure 3 Schematic diagram of the relationship between the negative torque, induced back electromotive force, speed and phase current of the motor in an embodiment of the present invention;

[0020] Figure 4 Schematic diagram of state transition of a motor controller according to an embodiment of the present invention;

[0021] Figure 5 A schematic diagram of a motor controller safely exiting FW mode in an embodiment of the present invention;

[0022] Figure 6 A schematic diagram of a motor controller safely exiting an ASC mode according to an embodiment of the present invention;

[0023] Figure 7 This is a functional module diagram of a fault handling device for a vehicle electric drive system according to an embodiment of the present invention;

[0024] Figure 8 Schematic diagram of the structure of a vehicle in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] In the present invention, descriptions such as "first" and "second" are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions of various embodiments may be combined with each other, but this must be based on the fact that they can be implemented by a person of ordinary skill in the art. If the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0027] The embodiment of the present invention provides a method for troubleshooting a vehicle electric drive system, referring to Figure 1 As shown, the method includes the following steps S101 to S103:

[0028] S101: In response to a preset fault signal of the vehicle electric drive system, the motor controller controlling the vehicle electric drive system switches from a normal mode to a safe mode, where the safe mode prohibits the vehicle controller from issuing control instructions to the motor controller.

[0029] It should be noted that the fault signals of the vehicle's electric drive system may include level 1 fault, level 2 fault and level 3 fault. Among them, in the case of a level 3 fault, it may have a major impact on the vehicle and it is necessary to stop driving immediately. In the case of a level 2 fault, it is necessary to go to a vehicle repair site as soon as possible for processing. In the case of a level 1 fault, it is not necessary to go to a vehicle repair site as soon as possible for processing, and it can be processed during vehicle maintenance. The preset fault signal may refer to a level 3 fault. In addition, the normal mode is a mode that allows the vehicle controller to send control instructions to the motor controller. In the normal mode, there is no serious fault in the vehicle's electric drive system, and the power of the vehicle will not be restricted.

[0030] In some embodiments, controlling the motor controller of the vehicle electric drive system to switch from normal mode to safe mode includes: obtaining the motor speed of the vehicle electric drive system; if the motor speed is greater than a preset speed threshold, controlling the motor controller of the vehicle electric drive system to switch from normal mode to ASC mode; if the motor speed is less than or equal to the preset speed threshold, controlling the motor controller of the vehicle electric drive system to switch from normal mode to FW mode.

[0031] It should be noted that the safety mode can be ASC (Active Short Circuit) mode or FW (Free-Wheeling) mode. When the motor speed is greater than the preset speed threshold, that is, high speed, if the safety mode is FW mode, the induced back electromotive force of the motor of the vehicle's electric drive system is high, which will damage the battery. Therefore, at this time, the motor controller that controls the electric drive system switches from normal mode to ASC mode, avoiding battery damage in FW mode, thereby reducing the possibility of battery damage; when the motor speed is less than or equal to the preset speed threshold, that is, low speed, if the safety mode is ASC mode, the vehicle's electric drive system will generate a large negative torque, which is manifested as an increase in the vehicle's drag force, thereby causing a sharp change in vehicle speed. Therefore, the motor controller that controls the electric drive system switches from normal mode to FW mode, avoiding a sharp change in vehicle speed in ASC mode, thereby avoiding rear-end collisions, and improving vehicle driving safety.

[0032] S102: After the motor controller enters the safety mode, if a preset condition is met, a software control program for controlling the motor controller is adjusted to allow the vehicle controller to send control instructions to the motor controller.

[0033] In some embodiments, adjusting the software control program for controlling the motor controller may include resetting a fault state of the vehicle electric drive system in the software control program.

[0034] It should be noted that resetting the fault state may refer to setting the third-level fault of the vehicle electric drive system to no fault.

[0035] S103: If a target control instruction is issued to the motor controller after the software control program is adjusted, the motor controller is controlled to execute the target control instruction according to the safety response strategy.

[0036] It should be noted that the target control instruction may be a torque request instruction, a speed request instruction, a standby request instruction, and the like.

[0037] In some implementations, the command response speed in the safe mode is slower than the command response speed in the normal mode.

[0038] In some embodiments, the target control instruction is a torque request instruction, and controlling the motor controller to execute the target control instruction according to the safety response strategy may include the following steps S1031 to S1033:

[0039] S1031: Control the motor controller to switch from safety mode to normal mode.

[0040] S1032: During a first period after the motor controller switches to the normal mode, the motor controller controls the output torque of the motor to be maintained at a preset torque.

[0041] It should be noted that the preset torque is a relatively small torque. By controlling the output torque of the motor to be maintained at the preset torque through the motor controller, the stability of the motor controller can be ensured. The preset torque may be 0 Nm.

[0042] In some embodiments, the safety mode is FW mode, and controlling the output torque of the motor to maintain at a preset torque through the motor controller may include: performing closed-loop control on the output torque of the motor through the motor controller to maintain the output torque of the motor at the preset torque.

[0043] In other embodiments, the safety mode is an ASC mode, and the output torque of the motor is controlled by the motor controller to maintain it at a preset torque, which may include: performing a first open-loop control on the dq axis voltage of the motor by the motor controller to put the motor controller in an active short-circuit state; after the motor controller is in the active short-circuit state, performing a second open-loop control on the dq axis voltage of the motor by the motor controller to make the dq axis weak magnetic voltage of the motor offset the induced back electromotive force of the motor; after the dq axis weak magnetic voltage of the motor offsets the induced back electromotive force of the motor, performing closed-loop control on the output torque of the motor by the motor controller to maintain the output torque of the motor at a preset torque.

[0044] In some embodiments, performing a first open-loop control on the dq-axis voltages of the motor by the motor controller may include: performing open-loop control on the dq-axis voltages of the motor by the motor controller based on a preset voltage so that the motor controller is in an active short-circuit state. Performing a second open-loop control on the dq-axis voltages of the motor by the motor controller may include: performing open-loop control on the dq-axis voltages of the motor by the motor controller based on a preset voltage range so that the dq-axis field-weakening voltages of the motor offset the induced back electromotive force of the motor, wherein the preset voltage is less than or equal to a lower limit of the preset voltage range.

[0045] It should be noted that the preset voltage can be 0V, that is, the d-axis voltage and q-axis voltage of the motor are both 0V, so that the motor controller is in an active short-circuit state. Based on the preset voltage range, the motor controller performs open-loop control of the dq-axis voltages of the motor, which can control the d-axis voltage of the motor to 0V, and the magnitude of the q-axis voltage corresponds to the induced back electromotive force of the motor. In addition, since the induced back electromotive force of the motor corresponding to different motor speeds is different, the preset voltage range can also be determined according to the motor speed.

[0046] It should be noted that in FW mode, closed-loop control can be performed directly. The reason is that although there will be short-term spike voltages and spike currents, the hardware will not be damaged due to the low motor speed. In ASC mode, closed-loop control cannot be performed directly. The reason is that if the loop is closed directly, the high spike voltages and spike currents may damage the hardware due to the high motor speed. Therefore, the embodiment of the present invention is limited to the ASC mode, first performing the first open-loop control and the second open-loop control, and then performing closed-loop control, to avoid hardware damage caused by high spike voltages and spike currents, avoid damage to the vehicle, and thus improve the driving safety of the vehicle.

[0047] S1033: In a second period after the first period, the motor controller is used to control the output torque of the motor to gradually increase from the preset torque to the target torque indicated by the torque request instruction.

[0048] It should be noted that if the motor controller is directly controlled to respond to the torque request command after receiving it, it may cause a sudden increase in the motor's output torque, leading to abnormal conditions such as a sudden change in motor speed and vehicle jerking. Furthermore, since the vehicle's electric drive system may be abnormal at this time, the risk of vehicle damage is further increased. Therefore, the embodiments of the present invention limit the control of the motor controller to gradually increase the motor's output torque from a preset torque to the target torque indicated by the torque request command. This avoids sudden increases in the motor's output torque, thereby preventing abnormal conditions such as a sudden change in motor speed and vehicle jerking, and reduces the risk of vehicle damage.

[0049] In some embodiments, controlling the output torque of the motor to gradually increase from a preset torque to a target torque indicated by a torque request instruction by a motor controller may include: controlling the output torque of the motor to gradually increase from a preset torque to the target torque indicated by the torque request instruction according to a linear increasing trend by the motor controller; or controlling the output torque of the motor to gradually increase from a preset torque to the target torque indicated by the torque request instruction according to a nonlinear increasing trend by the motor controller.

[0050] It should be noted that the reference Figure 2 As shown in (a), Figure 2 Schematic diagram of a linear increase trend and a nonlinear increase trend in an embodiment of the present invention. The linear increase trend makes the torque increase of the motor equal per unit time. Under the linear increase trend, the control of the output torque is simplified.

[0051] In some embodiments, reference Figure 2 As shown in (b), the nonlinear increase trend results in a greater increase in the motor's output torque as the time becomes later. It should be noted that if a hardware fault exists in the vehicle's electric drive system, then while controlling the motor controller to execute the target control command according to the safety response strategy, the motor controller will switch from normal mode to safe mode again and cease executing the target control command. In other words, the later the time, the lower the probability that the motor controller will switch from normal mode to safe mode again, i.e., the lower the probability that the vehicle's electric drive system has a hardware fault. Therefore, at earlier times, the increase in the motor's output torque is smaller, preventing damage to the vehicle due to a sudden increase in the motor's output torque in the event of a hardware fault in the vehicle's electric drive system, thereby improving vehicle driving safety. At later times, the increase in the motor's output torque is larger, indicating a lower probability of a hardware fault in the vehicle's electric drive system. This speeds up the motor's output torque response, thereby improving the driving experience. Thus, both improved vehicle driving safety and enhanced driving experience are achieved.

[0052] In other embodiments, reference Figure 2As shown in (c), the nonlinear increasing trend makes the increasing trend of the motor output torque smaller as the time is later.

[0053] In some embodiments, the preset conditions may include: the duration for the motor controller to execute the target control instruction is less than a preset duration threshold, and the number of times the motor controller executes the target control instruction is less than a preset number threshold.

[0054] It should be noted that the preset time threshold may be 3 seconds or 4 seconds, etc., and the preset number threshold may be 3 times or 4 times, etc.

[0055] It should be noted that if the fault is caused by a general program error, then after adjusting the software control program for controlling the motor controller, in theory, the motor controller can be successfully controlled to execute the target control instruction in accordance with the safety response strategy to achieve safe exit from the safety mode. However, if there is a hardware fault in the vehicle electric drive system, then in the process of controlling the motor controller to execute the target control instruction in accordance with the safety response strategy, it will again respond to the preset fault signal of the vehicle electric drive system, and control the motor controller of the vehicle electric drive system to switch from normal mode to safe mode. Then, the software control program for controlling the motor controller is adjusted to control the motor controller to execute the target control instruction in accordance with the safety response strategy. After multiple cycles, if no termination condition is set, it will enter an infinite loop and cannot achieve safe exit from the safety mode. Therefore, the embodiment of the present invention limits the above-mentioned time length and number of times to avoid the motor controller constantly responding to the target control instruction in the event of a hardware fault, thereby avoiding damage to vehicle parts and components, thereby extending the service life of vehicle parts and components.

[0056] It's important to note that a failure in the electric drive system manifests as power loss and vehicle stalling, posing a serious threat to driver safety and the manufacturer's reputation. Therefore, ensuring that the electric drive system can recover after a failure and ensuring stable high-speed operation is a key technical challenge for new energy vehicles. When a Level 3 fault occurs, the vehicle should stop immediately. However, in practice, to reduce the probability of stalling, the motor controller enters FW or ASC mode, causing the vehicle to enter limp mode. To address this issue, the embodiments of the present invention offer only software strategy optimizations, requiring no hardware changes or costs, making them easy to implement. Once implemented, the solution proactively exits the FW / ASC safe state, restoring normal electric drive power, provided that the fault recovery conditions are met. This significantly improves the customer experience and driving safety. For example, in the case of stalling or low-speed limp mode under conventional solutions, this solution can quickly restore the motor to normal operation, avoiding stalling, speed reduction, and subsequent adverse events. Finally, power system stalling issues fall under the "Three Guarantees" service and are a frequent source of customer complaints. Through the embodiments of the present invention, the possibility of customer complaints can be greatly reduced. Even if a serious level 3 electric drive failure occurs, the vehicle can still return to the store for repair under normal power after recovery, and the customer's perception of the severity of the problem is greatly reduced.

[0057] refer to Figure 3 As shown, Figure 3 It is a schematic diagram of the relationship between the negative torque, induced back electromotive force, speed and phase current of the motor in the embodiment of the present invention. Regarding the ASC mode and the FW mode, the intersection of the negative torque generated by the motor is ①. After the electric drive system fails, the motor speed is continuously monitored. If the current motor speed is less than the speed corresponding to point ①, the motor controller enters the FW mode. If the current motor speed is greater than the speed corresponding to point ①, the motor controller enters the ASC mode. Among them, the FW mode is a full-shutdown protection function, and the implementation principle is achieved by fully shutting down the upper and lower bridge arms of the inverter circuit. At this time, the relationship between the output torque of the motor and the speed, and the relationship between the induced back electromotive force and the speed is as follows: Figure 3 As shown. ASC mode is the three-phase active short-circuit protection function. The implementation principle is to fully turn on the upper bridge arm of the inverter circuit and turn off the lower bridge arm, or turn off the upper bridge arm and turn on the lower bridge arm. At this time, the relationship between the motor's output torque and speed, and the relationship between the three-phase current and speed are as follows: Figure 3 The above characteristics can only meet the normal switching between ASC and FW modes after a level 3 serious fault occurs. That is, the motor is in ASC mode at high speed and in FW mode at medium and low speeds, and the negative torque is always kept in a reasonable state.

[0058] It should be noted that for two-wheel drive vehicles, after a motor failure, the vehicle enters safety mode, losing propulsion and ensuring only smooth deceleration and stopping. For four-wheel drive vehicles, if a single electric drive fails, the vehicle enters safety mode, relying on the remaining functioning electric drive for propulsion. The vehicle can limp along at a limited speed under the control of the vehicle controller. However, regardless of the vehicle type, an electric drive failure can compromise driving safety and the overall driving experience. Current conventional solutions fail to safely exit safety mode and fail to fundamentally address these issues, leading to significant market complaints. In limp-away mode, the vehicle controller issues a torque request to the motor controller of the functioning electric drive but not to the motor controller of the faulty electric drive, ensuring normal operation of the single electric drive. For example, when the vehicle enters limp-away mode, the vehicle speed is limited to 20 km / h, and the maximum output torque of the functioning electric drive in limp-away mode is 60 Nm. After an electric drive failure in a two-wheel drive vehicle, the safe mode cannot be exited during the current driving cycle and must be restored after the vehicle is abandoned and powered on and off. After a single electric drive failure occurs in a four-wheel drive vehicle, it can enter a safe state and continue driving, but the limp vehicle speed is too low, and a sudden deceleration on the road can easily cause accidents such as rear-end collisions. In order to solve the above problems, the embodiment of the present invention actively exits the safe state of the motor controller, allowing the vehicle to be driven normally again after a short transition, thus avoiding the situation of breaking down. In addition, the embodiment of the present invention actively exits the safe state of the motor controller, allowing the vehicle to restore the four-wheel drive power without the driver's obvious perception, thereby optimizing the driving experience. Finally, the embodiment of the present invention also realizes that after a serious electric drive failure, if the fault recovery conditions are met, the FW and ASC modes can be actively exited, thereby transitioning to a normal working state, and exiting the FW and ASC modes will not cause secondary damage to the vehicle.

[0059] refer to Figure 4 As shown, Figure 4This is a schematic diagram of the state transition of the motor controller in an embodiment of the present invention. Among the states of the motor controller (MCU), Standby is the MCU ready state, Torque is the MCU torque state, Speed ​​is the MCU speed state, Fault is the MCU three-level fault state, VCU_StateCmd is the state request of the VCU (Vehicle Control Unit) to the MCU, FaultLevel is the fault severity level of the MCU, Pre-Fault is the MCU pre-fault state, Recovery_Cnt is the number of recovery times, that is, the number of times the motor controller executes the target control instruction, and Recovery_Time is the recovery time, that is, the duration of the motor controller executing the target control instruction. From the state machine, it can be seen that after a three-level serious fault occurs in the electric drive system, the state machine jumps from the normal states of Standby, Torque, and Speed ​​to the Pre-Fault state, and enters the FW or ASC mode according to the switching threshold. From the state machine, it can be seen that within the current driving cycle, the MCU normal state to the Pre-Fault state is bidirectionally reversible, and the Pre-Fault state to the Fault state is unidirectional and irreversible. That is, if VCU_StateCmd is requested normally and FaultLevel == 0, the MCU can jump out of the Pre-Fault state and respond to the request; but if the recovery timeout or the recovery timeout is exceeded, it will no longer be able to respond.

[0060] refer to Figure 5 As shown, Figure 5 This is a schematic diagram of the motor controller safely exiting the FW mode in an embodiment of the present invention. When the motor controller meets the fault recovery conditions, the safe exit of the FW mode is explained. Taking the exit process of the third-level IGBT drive undervoltage fault in the FW mode pre-fault state as an example, the model is simulated and switched from the FW mode to the open-tube torque mode. Figure 5 As shown, Id is the d-axis current of the motor, Iq is the q-axis current of the motor, and MCU_Torque is the output torque of the motor. Figure 5The exit method is broken down as follows: First, the MCU meets the recovery conditions and exits from the Pre-Fault state to the Standby state, remaining in FW mode. Second, the MCU responds to a VCU state request, such as a VCU command for the Torque state. The strategy is designed to transition the MCU from FW mode to 0 Nm open-loop mode to ensure stable current loop control at the switchover point and prevent severe transient overcurrent. During the instantaneous open-loop mode, the UV and W three-phase currents experience a brief, millisecond-scale spike. The current is then measured at the highest FW speed. Ensure sufficient margin to meet these requirements when selecting hardware. Third, maintain 0 Nm closed-loop control for a period of time to ensure MCU stability. Fourth, the MCU responds to the VCU torque request, strategically adding a slope limit to the torque output to prevent sudden speed changes and jerks caused by the torque request step. This completes the process of exiting the Pre-Fault state in FW mode.

[0061] refer to Figure 6 As shown, Figure 6 The following is a schematic diagram of the safe exit of the motor controller from the ASC mode according to an embodiment of the present invention. When the motor controller meets the fault recovery conditions, the safe exit of the ASC mode is described. Taking the exit process of the IGBT drive undervoltage level 3 fault in the ASC mode pre-fault state as an example, the process of simulating the motor speed at 10000 rpm from the Pre-Fault state to enter the Torque state is shown in FIG. Figure 6 As shown, where Id is the d-axis current of the motor, Iq is the q-axis current of the motor, Ud is the d-axis voltage of the motor, Uq is the q-axis voltage of the motor, and MCU_Torque is the output torque of the motor. Figure 6 The following describes the exit method for the ASC mode: First, the MCU meets the recovery conditions and exits the Pre-Fault state into the Torque state, preparing to exit the ASC state, which is directly controlled by the driver chip hardware. Second, direct ASC control enters zero-voltage open-loop control with Ud = 0 and Uq = 0. At this time, the MCU remains in an active short-circuit state for the upper or lower three bridges. Third, the zero-voltage open-loop control transitions to back-EMF voltage open-loop control. Specifically, Ud = 0 and Uq transition from 0 to a field-weakening voltage that can offset the back-EMF at the current speed. At this point, the electric drive generates no additional drive torque, equivalent to 0 Nm open-loop control. Fourth, the 0 Nm open-loop control transitions to 0 Nm closed-loop control, which is maintained for a period of time to ensure MCU stability. Fifth, the MCU responds to the VCU torque request. The transition strategy is the same as for FW mode pre-fault state self-recovery. This completes the ASC mode Pre-Fault state exit process.

[0062] The embodiment of the present invention controls the motor controller of the vehicle electric drive system to switch from normal mode to safe mode in response to a preset fault signal of the vehicle electric drive system. The safe mode is a mode that prohibits the vehicle controller from sending control instructions to the motor controller. After the motor controller enters the safe mode, if the preset conditions are met, the software control program for controlling the motor controller is adjusted to allow the vehicle controller to send control instructions to the motor controller. If the target control instruction is sent to the motor controller after the software control program is adjusted, the motor controller is controlled to execute the target control instruction according to the safety response strategy. After the software control program is adjusted, the vehicle controller is allowed to send control instructions to the motor controller. If the target control instruction is sent to the motor controller, the motor controller is controlled to execute the target control instruction according to the safety response strategy. The motor controller can control the motor according to the target control instruction, thereby avoiding the problem of the vehicle breaking down or the power being weakened, and thus avoiding the occurrence of vehicle rear-end collisions. Therefore, the driving safety of the vehicle is improved.

[0063] Based on the same invention concept, Figure 7 As shown, an embodiment of the present invention provides a fault handling device 10 for a vehicle electric drive system, comprising: a switching unit 110, for controlling a motor controller of the vehicle electric drive system to switch from a normal mode to a safe mode in response to a preset fault signal of the vehicle electric drive system, wherein the safe mode is a mode in which the vehicle controller is prohibited from issuing control instructions to the motor controller; an adjustment unit 120, for adjusting a software control program for controlling the motor controller after the motor controller enters the safe mode if a preset condition is met, so as to allow the vehicle controller to issue control instructions to the motor controller; and an execution unit 130, for controlling the motor controller to execute the target control instruction in accordance with a safety response strategy if a target control instruction is issued to the motor controller after the software control program is adjusted.

[0064] It can be understood that the adjustment unit 120 is specifically used to reset the fault state of the vehicle electric drive system in the software control program.

[0065] It can be understood that the instruction response speed in the safety mode is lower than the instruction response speed in the normal mode, and the target control instruction is a torque request instruction. Then, the execution unit 130 includes: a switching subunit, which is used to control the motor controller to switch from the safety mode to the normal mode; a maintaining subunit, which is used to control the output torque of the motor to be maintained at a preset torque through the motor controller in a first time period after the motor controller switches to the normal mode; and a torque control subunit, which is used to control the output torque of the motor to gradually increase from the preset torque to the target torque indicated by the torque request instruction through the motor controller in a second time period after the first time period.

[0066] It can be understood that the safety mode is the FW mode, and the maintenance subunit is specifically used to: perform closed-loop control on the output torque of the motor through the motor controller to maintain the output torque of the motor at a preset torque.

[0067] It can be understood that if the safety mode is the ASC mode, then the maintenance subunit is specifically used to: perform a first open-loop control on the dq axis voltage of the motor through the motor controller to put the motor controller in an active short-circuit state; after the motor controller is in the active short-circuit state, perform a second open-loop control on the dq axis voltage of the motor through the motor controller to make the dq axis weak magnetic voltage of the motor offset the induced back electromotive force of the motor; after the dq axis weak magnetic voltage of the motor offsets the induced back electromotive force of the motor, perform closed-loop control on the output torque of the motor through the motor controller to maintain the output torque of the motor at a preset torque. Wherein, performing the first open-loop control on the dq axis voltage of the motor through the motor controller includes: based on a preset voltage, performing open-loop control on the dq axis voltage of the motor through the motor controller to put the motor controller in an active short-circuit state; performing the second open-loop control on the dq axis voltage of the motor through the motor controller includes: based on a preset voltage range, performing open-loop control on the dq axis voltage of the motor through the motor controller to make the dq axis weak magnetic voltage of the motor offset the induced back electromotive force of the motor, and the preset voltage is less than or equal to the lower limit of the preset voltage range.

[0068] It can be understood that the torque control subunit is specifically used to: control the output torque of the motor through the motor controller, gradually increasing from the preset torque to the target torque indicated by the torque request instruction according to a linear increasing trend; or control the output torque of the motor through the motor controller, gradually increasing from the preset torque to the target torque indicated by the torque request instruction according to a nonlinear increasing trend.

[0069] The preset conditions include: the duration for the motor controller to execute the target control instruction is less than a preset duration threshold, and the number of times the motor controller executes the target control instruction is less than a preset number threshold.

[0070] It should be understood that more implementation details of the vehicle electric drive system fault handling device 10 in the embodiment of the present invention are described in the aforementioned vehicle electric drive system fault handling method, and for the sake of brevity of the specification, they are not repeated here.

[0071] Based on the same inventive concept, an embodiment of the present invention further provides a vehicle, such as Figure 8 As shown, it includes a memory 804, a processor 802 and a computer program stored in the memory 804 and capable of running on the processor 802. The processor 802 executes the program to implement the steps described in any implementation of the embodiment of the vehicle electric drive system fault handling method.

[0072] Among them, Figure 8 In the embodiment of the present invention, a bus architecture (represented by bus 800) is shown. Bus 800 may include any number of interconnected buses and bridges, and bus 800 links together various circuits including one or more processors represented by processor 802 and memory represented by memory 804. Bus 800 may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. Bus interface 805 provides an interface between bus 800 and receiver 801 and transmitter 803. Receiver 801 and transmitter 803 may be the same component, namely a transceiver, which provides a unit for communicating with various other devices over a transmission medium. Processor 802 is responsible for managing bus 800 and general processing, while memory 804 may be used to store data used by processor 802 when performing operations.

[0073] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Other examples and implementations are within the scope and spirit of the present invention and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hardwiring, or a combination of any of these. Furthermore, each functional unit may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit.

[0074] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only exemplary. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0075] The units described as separate components may or may not be physically separated, and the components of the control device may or may not be physical units, that is, they may be located in one place or distributed over multiple units.

[0076] Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

[0077] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk, etc. Various media that can store program codes.

[0078] The foregoing description is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be included within the scope of the claims.

Claims

1. A method for troubleshooting a vehicle electric drive system, characterized in that: include: In response to a preset fault signal of the vehicle electric drive system, the motor controller of the vehicle electric drive system is switched from a normal mode to a safe mode, wherein the safe mode is a mode in which the vehicle controller is prohibited from issuing control instructions to the motor controller; After the motor controller enters the safety mode, if a preset condition is met, adjusting a software control program for controlling the motor controller to allow the vehicle controller to issue a control instruction to the motor controller; If a target control instruction is issued to the motor controller after adjusting the software control program, the motor controller is controlled to execute the target control instruction according to the safety response strategy, wherein, if the target control instruction is a torque request instruction, the motor controller is controlled to switch from the safety mode to the normal mode; within a first period after the motor controller switches to the normal mode, the output torque of the motor is controlled by the motor controller to maintain at a preset torque, wherein, if the safety mode is the ASC mode, the dq axis voltage of the motor is first open-loop controlled by the motor controller to put the motor controller in an active short-circuit state state; after the motor controller is in the active short-circuit state, the motor controller performs a second open-loop control on the dq-axis voltage of the motor, so that the dq-axis weak magnetic voltage of the motor offsets the induced back electromotive force of the motor; after the dq-axis weak magnetic voltage of the motor offsets the induced back electromotive force of the motor, the motor controller performs closed-loop control on the output torque of the motor, so that the output torque of the motor is maintained at the preset torque; in a second time period after the first time period, the motor controller controls the output torque of the motor to gradually increase from the preset torque to the target torque indicated by the torque request instruction.

2. The method for troubleshooting a vehicle electric drive system according to claim 1, characterized in that: The adjusting of the software control program for controlling the motor controller includes: Reset the fault state of the vehicle electric drive system in the software control program.

3. The method for troubleshooting a vehicle electric drive system according to claim 1, wherein: The instruction response speed in the safe mode is lower than the instruction response speed in the normal mode.

4. The method for troubleshooting a vehicle electric drive system according to claim 1, wherein: The safety mode is the FW mode, and controlling the output torque of the motor to maintain at a preset torque by the motor controller includes: The motor controller performs closed-loop control on the output torque of the motor so that the output torque of the motor is maintained at the preset torque.

5. The method for troubleshooting a vehicle electric drive system according to claim 1, wherein: The step of controlling the motor controller to gradually increase the output torque of the motor from the preset torque to the target torque indicated by the torque request instruction includes: Controlling the output torque of the motor by the motor controller to gradually increase from the preset torque to the target torque indicated by the torque request instruction in a linear increasing trend; or The motor controller controls the output torque of the motor to gradually increase from the preset torque to the target torque indicated by the torque request instruction according to a nonlinear increasing trend.

6. The method for troubleshooting a vehicle electric drive system according to claim 1, wherein: The preset conditions include: The duration for the motor controller to execute the target control instruction is less than a preset duration threshold, and the number of times the motor controller executes the target control instruction is less than a preset number threshold.

7. A fault handling device for a vehicle electric drive system, characterized in that: include: a switching unit, configured to control a motor controller of the vehicle electric drive system to switch from a normal mode to a safe mode in response to a preset fault signal of the vehicle electric drive system, wherein the safe mode is a mode in which a vehicle controller is prohibited from issuing control instructions to the motor controller; an adjustment unit, configured to, after the motor controller enters the safety mode, adjust a software control program for controlling the motor controller if a preset condition is met, so as to allow the vehicle controller to issue a control instruction to the motor controller; An execution unit is configured to, if after adjusting the software control program, issue a target control instruction to the motor controller, control the motor controller to execute the target control instruction in accordance with a safety response strategy, wherein if the target control instruction is a torque request instruction, control the motor controller to switch from the safety mode to the normal mode; within a first period after the motor controller switches to the normal mode, control the output torque of the motor to be maintained at a preset torque through the motor controller, wherein, if the safety mode is the ASC mode, perform a first open-loop control on the dq axis voltage of the motor through the motor controller to make the motor controller in a state of active short-circuit state; after the motor controller is in the active short-circuit state, the motor controller performs a second open-loop control on the dq axis voltage of the motor, so that the dq axis weak magnetic voltage of the motor offsets the induced back electromotive force of the motor; after the dq axis weak magnetic voltage of the motor offsets the induced back electromotive force of the motor, the motor controller performs closed-loop control on the output torque of the motor, so that the output torque of the motor is maintained at the preset torque; in a second time period after the first time period, the motor controller controls the output torque of the motor to gradually increase from the preset torque to the target torque indicated by the torque request instruction.

8. A vehicle, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 6 when executing the computer program.

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