Multi-gear drive motor overspeed grading processing method and device for multi-drive vehicle

Abstract

The application discloses a kind of multi-drive automobile multi-gear drive motor overspeed grading processing method and device.The method is applied to motor controller, obtains the real-time speed of drive motor and is compared with first, second, third speed threshold value in turn increasing: not greater than first threshold value, according to vehicle control instruction output torque;Between first, second threshold value, reduce torque and take torque minimum value to multiple-way instruction;Between second, third threshold value, combined with gear shift state collaborative protection, neutral applies negative torque, zero torque is outputted when gear is taken off, and gear is requested to cut into neutral;Greater than third threshold value, make motor enter three-phase short-circuit state and long-span lock.When resolver fails, speed, gear and wheel rolling radius reconstruct speed.The application grades and inhibits motor overspeed, avoids vehicle power loss while ensuring motor and vehicle safety.

Description

Technical Field

[0001] This invention belongs to the field of automotive motor control technology, specifically relating to a method and device for graded overspeed processing of multi-drive vehicle multi-gear drive motors. Background Technology

[0002] The electric drive system is a core component of new energy vehicles, and its operational safety is paramount. During vehicle operation, factors such as downhill slippage, sudden changes in road surface adhesion, transmission system malfunctions, or control anomalies can cause the drive motor to enter an overspeed operating state. Overspeeding of the drive motor causes its back electromotive force (EMF) to increase dramatically with increasing speed. On the one hand, this can trigger uncontrolled rectification, where the back EMF flows back to the DC bus via the inverter's freewheeling diodes, causing overvoltage and potentially damaging power devices and the battery system. On the other hand, it can also lead to abnormal power output and even loss of vehicle control, seriously threatening the lives and property of passengers. Therefore, timely and effective handling of drive motor overspeed is a crucial issue for ensuring the safety of new energy vehicles, especially for vehicles equipped with multiple electric drive systems and multi-speed transmissions, where handling drive motor overspeed is even more complex.

[0003] Existing drive motor overspeed protection typically employs a simplistic and crude approach. For example, it may directly cut off the output torque or trigger the motor's three-phase short-circuit protection upon detecting that the motor speed exceeds a certain limit. This approach lacks differentiation in the degree of overspeed, and its intervention is often too aggressive, easily causing a sudden loss of vehicle driving force and affecting drivability and driving safety. Furthermore, its insufficient intervention makes it difficult to effectively suppress the continuously increasing motor speed.

[0004] Furthermore, in vehicles equipped with multi-speed transmissions, the braking deceleration of the drive motor is closely coupled with the shifting state of the transmission mechanism, and existing overspeed protection schemes generally lack coordination between the two. For example, when the drive motor is mechanically connected to the wheel via a gear, directly applying reverse braking torque to the motor will cause the braking force to act back on the wheel through the transmission gears, affecting the entire vehicle. Or, when the transmission mechanism is in the process of disengaging (gear disengagement), if braking torque is still applied to the motor, the disengaging meshing gear will be subjected to additional stress and locked, causing the disengagement action to fail to be completed smoothly, resulting in electromechanical interference and jamming.

[0005] Furthermore, motor speed is typically obtained by decoding data from a rotary transformer. If the rotary transformer malfunctions or communication is lost, the controller loses its speed data, rendering overspeed protection ineffective. Additionally, if short-circuit protection triggered under extreme overspeed conditions exits with hysteresis logic and experiences only a small hysteresis, the repeated rise and fall of motor speed near the limit will cause repeated switching of the protection state, resulting in torque and current oscillations. Moreover, the aforementioned processing logic involving gear shifting judgment is usually only compatible with specific vehicle platforms, lacking compatibility with simplified platforms that only equip a single electric drive assembly or whose electric drive assembly lacks a gear shifting mechanism. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the aforementioned background technology by providing a method and device for graded overspeed processing of multi-drive vehicle multi-gear drive motors. This method effectively suppresses motor overspeed, ensures the safety of the motor and the entire vehicle, minimizes the loss of vehicle power, and properly addresses issues such as electromechanical coordination, sensor failure tolerance, vibration exit, and platform compatibility.

[0007] The technical solution adopted in this invention is: a method for graded overspeed processing of multi-drive vehicle multi-gear drive motors, applied to a motor controller, the method comprising: Obtain the real-time motor speed of the drive motor; The real-time motor speed is compared with a preset first speed threshold, a second speed threshold, and a third speed threshold, wherein the first speed threshold is less than the second speed threshold, and the second speed threshold is less than the third speed threshold; When the real-time motor speed is not greater than the first speed threshold, the target drive torque is output according to the control command of the vehicle controller. When the real-time motor speed is greater than the first speed threshold and not greater than the second speed threshold, the first-level torque reduction protection control logic is executed to reduce the output torque of the drive motor and suppress the real-time motor speed from continuing to rise. When the real-time motor speed is greater than the second speed threshold and not greater than the third speed threshold, a second-level cooperative overspeed protection is performed on the drive motor. The second-level cooperative overspeed protection includes: controlling the output torque of the drive motor and / or sending a gear shifting request to the vehicle controller. For vehicles equipped with a gear shifting mechanism, the motor controller obtains the gear shifting status signal of the transmission controller in real time through the controller area network bus, and determines the above control method based on the mechanical connection status fed back by the gear shifting status signal. When the real-time motor speed exceeds the third speed threshold, the third-level extreme overspeed protection logic is executed, causing the drive motor to enter a three-phase short-circuit state to suppress the back electromotive force generated by overspeed.

[0008] In the above technical solution, when the real-time motor speed is greater than the first speed threshold and not greater than the second speed threshold and the first-level torque reduction protection control logic is executed, the motor controller synchronously receives the control command from the vehicle controller, the overspeed torque reduction protection command set by the motor controller itself, and other fault protection commands built into the motor controller; the motor controller calculates the output torque value requested by each of the above commands in real time, and selects the minimum value among the output torque values ​​as the target drive torque finally output by the drive motor.

[0009] In the above technical solution, in the second-level cooperative overspeed protection, when the gearbox controller is determined to be in neutral with the mechanical connection disconnected based on the shift status signal, the motor controller performs the negative torque protection function and sends a speed reduction request signal to the instrument panel through the controller local area network bus to prompt the vehicle to reduce its speed to the preset target speed.

[0010] In the above technical solution, in the second-level cooperative overspeed protection, when the gearbox controller is determined to be in the disengagement process of the disengaged gear based on the shift status signal, the motor controller blocks the negative braking request, forcibly outputs a zero torque control command, and sends a speed reduction request signal to the instrument panel to prompt the vehicle to slow down to the preset target speed.

[0011] In the above technical solution, in the second-level cooperative overspeed protection, when it is determined based on the shift status signal that the transmission controller is neither in neutral nor in the process of disengaging, the motor controller sends a command to the vehicle controller via the controller area network bus to request to shift into neutral; while waiting for the neutral shift response, the motor controller executes the negative torque protection function and sends a speed reduction request signal to the instrument panel to prompt the vehicle to slow down to the preset target speed.

[0012] In the above technical solution, the third-level extreme overspeed protection logic includes: the motor controller executes an active short-circuit protection function, controls the power switching devices of the motor inverter to establish a three-phase internal short-circuit conduction loop, and sends a speed reduction request signal to the instrument panel to prompt the vehicle to reduce its speed to a preset target speed; after the active short-circuit protection function is triggered, the motor controller establishes a state lock, and even if the real-time motor speed falls below the third speed threshold or even below the second speed threshold, the three-phase internal short-circuit conduction loop is maintained until the real-time motor speed falls to no more than the first speed threshold, at which point the active short-circuit protection function is exited.

[0013] In the above technical solution, the method further includes a step of monitoring the electrical and communication anomalies of the rotary transformer that collects the real-time motor speed. When it is determined that the rotary transformer has a decoding failure or communication loss, resulting in the failure of the motor controller's speed acquisition link, the motor controller switches the speed signal source and obtains the real-time vehicle speed signal and the current gear signal fed back by the transmission controller through the controller area network bus. The motor controller converts the vehicle speed signal into wheel speed according to the pre-calibrated wheel rolling radius, and calculates the current motor speed by combining it with the pre-calibrated transmission ratio corresponding to the current gear. The calculated current motor speed is used as the real-time motor speed. The motor controller replaces the speed value that was originally collected by the rotary transformer and is now invalid with this real-time motor speed for comparison with the first speed threshold, the second speed threshold, and the third speed threshold.

[0014] In the above technical solution, the method further includes the step of identifying the vehicle electric drive topology; when it is identified that the current vehicle is only equipped with a single electric drive assembly or the electric drive assembly does not have a shift mechanism, in the second-level cooperative overspeed protection, the motor controller omits the acquisition and parsing of the shift status signal of the transmission controller, and determines the control of the output torque of the drive motor to perform the negative torque protection function so as to reduce the speed of the drive motor.

[0015] This invention provides an overspeed classification treatment device for multi-drive automobile multi-gear electric drive motors, comprising: The speed acquisition module is used to acquire the real-time motor speed of the drive motor; The communication protocol interaction module is used for data interaction with the vehicle controller and the transmission controller via the controller area network bus. A multi-level threshold determination module is used to determine the interval in which the real-time motor speed is located, which is divided by a first speed threshold, a second speed threshold, and a third speed threshold, wherein the first speed threshold is less than the second speed threshold, and the second speed threshold is less than the third speed threshold; The electromechanical coordination command output module is used to control the torque of the drive motor according to the shifting state of the gearbox controller when the real-time motor speed is greater than the second speed threshold and not greater than the third speed threshold, or to send a gear shifting request to the vehicle controller. The device is configured to perform the various steps of the overspeed classification processing method for multi-drive vehicle multi-gear drive motors as described in the above technical solution.

[0016] This invention provides a new energy multi-electric drive assembly collaborative architecture system, including multiple electric drive assemblies providing power, a shifting mechanism for mechanical gear switching, and a vehicle controller, a transmission controller, and a motor controller that are interconnected and coupled. The transmission controller is configured to provide feedback on the gear status and shifting process information of the transmission system. The motor controller is configured to execute the overspeed classification processing method for multi-drive vehicle multi-gear drive motors as described in the above technical solution. The motor controller and the transmission controller are integrated to shorten the transmission time of gear signals.

[0017] This invention provides a non-volatile computer-readable storage medium storing computer program instructions. When these computer program instructions are loaded and executed by a microprocessor in an onboard computing platform or motor controller, they implement the various steps of the overspeed classification processing method for multi-drive vehicle multi-gear drive motors as described in the above technical solution.

[0018] The beneficial effects of the present invention are as follows: The present invention divides the overspeed state of the drive motor into multiple intervals with progressively increasing speed thresholds of a first speed threshold, a second speed threshold, and a third speed threshold, and increases the intervention intensity step by step as the interval is upgraded, thereby taking corresponding treatment measures for different degrees of overspeed, effectively suppressing drive motor overspeed, intelligently protecting the motor and vehicle safety, and minimizing the loss of vehicle power.

[0019] Specifically, in each processing stage: In the mild overspeed range, arbitration is performed by taking the minimum torque requested by the vehicle controller's control commands, overspeed torque reduction protection commands, and other fault protection commands. This ensures timely overspeed torque reduction while eliminating conflicts between multiple protection commands, preventing excessive drive torque from being mistakenly output to the motor. In the moderate overspeed range, by acquiring the shifting status of the transmission mechanism in real time and coordinating control accordingly, appropriate measures can be taken for different mechanical connection states—applying negative torque braking in neutral can quickly reduce the motor speed without affecting the wheels and the entire vehicle, and in disengagement... During the process, the output is changed to zero torque, which can eliminate gear lock-up caused by braking torque, ensure smooth gear shifting and avoid electromechanical interference and jamming. In the geared state, it actively requests to switch to neutral across the controller domain, which can facilitate electromechanical decoupling before braking, thus taking into account both motor deceleration and vehicle safety. In the extreme overspeed range, by putting the motor into a three-phase short circuit state, the back electromotive force energy can be consumed inside the motor, effectively suppressing failures such as uncontrolled rectification. Moreover, by using a long-span asymmetric locking triggered by the third speed threshold and exiting only when the speed drops back to the first speed threshold, the oscillation caused by repeatedly entering and exiting short circuit protection near the threshold is avoided.

[0020] Furthermore, when the rotary transformer that collects motor speed fails, this invention can reconstruct the motor speed based on the vehicle speed, current gear, and wheel rolling radius, enabling the overspeed classification protection to continue operating in a downgraded manner and remain effective even when the sensor fails, significantly improving the robustness and functional safety level of the system. Moreover, by identifying the vehicle's electric drive topology, this invention can also automatically omit gear shift judgment and directly execute deceleration protection on simplified platforms that only have a single electric drive assembly or do not have a gear shifting mechanism, thereby achieving backward compatibility and reuse of the same control framework, improving the platform adaptability and versatility of the solution.

[0021] Accordingly, the electric drive control device, the multi-electric drive assembly cooperative architecture system, and the non-volatile computer-readable storage medium provided by the present invention implement the above method from the perspectives of functional modules, vehicle system architecture, and program products, respectively, and can obtain the same beneficial effects as the above method. Attached Figure Description

[0022] Figure 1 A flowchart of the overspeed classification processing method for multi-drive vehicle multi-gear drive motors provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of signal transmission for overspeed graded processing of multi-drive vehicle multi-gear drive motors provided in an embodiment of the present invention. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but these descriptions do not constitute a limitation on the present invention.

[0024] The embodiments of this invention mainly involve three major controllers: the vehicle control unit (VCU), the motor controller (MCU), and the transmission controller (TCU), as well as a drive motor driven by the motor controller and a shifting mechanism controlled by the transmission controller; the controllers interact with each other via a controller area network (CAN) bus. Figure 2 As shown, the vehicle controller sends control commands such as speed or torque to the motor controller via the CAN bus, and transmits information signals such as vehicle speed and gear position to the motor controller; the vehicle controller transmits shift control commands to the transmission controller via the CAN bus; the motor controller feeds back information signals such as motor speed, temperature, and faults to the vehicle controller via the CAN bus; the transmission controller feeds back information such as gear position and shift status to the vehicle controller via the CAN bus; the transmission controller can also directly transmit the above signals to the motor controller via the CAN bus. In a preferred embodiment, the motor controller and the transmission controller adopt an integrated design (e.g., sharing the same control board) to shorten the transmission time of gear position and other signals between the two.

[0025] In this invention, the first speed threshold n1, the second speed threshold n2, and the third speed threshold n3 used to determine the motor speed, as well as the target vehicle speed V used for instrument indication, can all be calibrated according to the characteristics of the drive motor and the safety requirements of the vehicle, and satisfy n1 < n2 < n3. As an example and not a limitation, for a drive motor with a peak speed of approximately 12000 r / min and a maximum operating speed of 16000 rpm, n1 = 12000 r / min, n2 = 14000 r / min, n3 = 15500 r / min, and V = 80 km / h can be calibrated; those skilled in the art can adjust the above calibration values ​​according to actual needs.

[0026] Example 1 See Figure 1 This embodiment provides a method for classifying and processing overspeed of multi-speed drive motors in multi-drive vehicles, which is applied to motor controllers. The method is executed in real time and cyclically by the motor controller when the drive motor is running, and includes the following steps S100 to S600.

[0027] As the overall design concept of this embodiment, the following will first explain the motivation, technical principle and technical effect of improving the "hierarchical processing" framework itself.

[0028] Once the drive motor exceeds its speed, it will generate increasingly higher back electromotive force (EMF) as the speed increases. This may lead to uncontrolled rectification (back EMF flowing back into the DC bus via the inverter diodes, causing overvoltage on the bus) and loss of vehicle control, threatening personal and property safety. However, the risk levels and available safety measures vary depending on the degree of overspeed. If a single measure is used indiscriminately (e.g., triggering a three-phase short circuit in the motor upon exceeding the speed limit), the overall vehicle power and drivability will be excessively sacrificed, while insufficient measures will fail to effectively suppress overspeed. This embodiment uses three progressively increasing speed thresholds n1 < n2 < n3 to divide the drive motor's operating state into four ranges: "normal - mild overspeed - moderate overspeed - extreme overspeed." The intervention intensity increases progressively with each range, from normal output to torque reduction protection, to electromechanical coordination protection, and finally to three-phase short circuit protection. This constitutes a closed-loop hierarchical control system that effectively suppresses drive motor overspeed, ensures the safety of the motor and the entire vehicle, and minimizes the loss of vehicle power, achieving intelligent and hierarchical overspeed protection.

[0029] Step S100: Obtain the real-time motor speed of the drive motor. Typically, the motor controller acquires the rotor position signal of the drive motor through a resolver sensor and decodes and calculates the real-time motor speed.

[0030] In a preferred embodiment of step S100, when the rotary transformer fails, the motor controller obtains the real-time motor speed via a reconfiguration method: the motor controller monitors the electrical and communication anomalies of the rotary transformer that collects the real-time motor speed; when it is determined that the rotary transformer has a decoding failure or communication loss, causing the motor controller's own internal circulation speed acquisition link to fail, the motor controller switches the speed signal source, obtaining the real-time vehicle speed signal provided by the vehicle controller via the CAN bus, and the current gear signal fed back by the transmission controller; the motor controller retrieves the pre-calibrated wheel rolling radius, first converts the vehicle speed signal into wheel speed, and then, combined with the pre-calibrated transmission ratio corresponding to the current gear, calculates the current motor speed. The conversion relationship is as follows: Wheel speed: n w = v / (2π·r) (Formula 1) Calculate the motor speed: n e = i · n w = (i · v) / (2π·r) (Formula 2) In the formula, nw is the wheel speed, v is the vehicle speed, r is the wheel rolling radius, ne is the calculated motor speed, and i is the gear ratio corresponding to the current gear. When v is in meters per second (m / s) and r is in meters (m), the units of nw and ne are revolutions per second (r / s), which are converted to revolutions per minute (r / min) by multiplying by 60. The vehicle speed is in kilometers per hour (km / h) and divided by 3.6 to convert to meters per second. The motor controller uses the calculated motor speed ne as the real-time motor speed, replacing the speed value originally collected by the rotary transformer, which is now invalid, for subsequent comparison with the first, second, and third speed thresholds.

[0031] Real-time motor speed is the sole basis for all graded judgments in this method, typically relying entirely on resolver acquisition and decoding. If the resolver fails to decode or loses communication, the internal circulation speed link of the motor controller fails, and the entire overspeed graded protection will fail due to the "loss of speed basis," posing a very high safety risk. This embodiment utilizes the physical transmission relationship determined between the vehicle speed, the current gear, and the wheel rolling radius to reconstruct the motor speed using a spatial physical model—first, the wheel speed is calculated from the vehicle speed using the wheel rolling radius (Formula 1), then the motor speed is inversely derived using the transmission ratio corresponding to the current gear (Formula 2), and this calculated speed replaces the failed sampled speed for continued threshold comparison. Even in the event of resolver failure, the system can still obtain reliable motor speed data, maintain continuous operation of the overspeed graded protection, achieve degraded operation and fault tolerance, and significantly improve the robustness and functional safety level of the control system.

[0032] Step S200: Compare the real-time motor speed with the preset first speed threshold n1, second speed threshold n2 and third speed threshold n3 (n1 < n2 < n3), and perform subsequent corresponding graded processing according to the interval in which the real-time motor speed is located.

[0033] Step S300: When the real-time motor speed is not greater than the first speed threshold n1, it is determined that the drive motor is in the normal operating range. The motor controller outputs the target drive torque according to the control command issued by the vehicle controller, and can simultaneously execute other fault protection strategies built into the motor controller.

[0034] Step S400: When the real-time motor speed is greater than the first speed threshold n1 and not greater than the second speed threshold n2, the motor controller executes the first-level torque reduction protection control logic to reduce the output torque of the drive motor and suppress the real-time motor speed from continuing to rise.

[0035] In a preferred embodiment of step S400, the motor controller synchronously receives the following parallel-triggered commands: control commands issued by the vehicle controller, overspeed torque reduction protection commands set by the motor controller itself, and other fault protection commands built into the motor controller; the motor controller calculates the output torque value requested by each of the above commands in real time, and selects the minimum value among them as the target drive torque for the final output of the drive motor.

[0036] In the mild overspeed range, the vehicle controller may still issue a large drive torque request due to driving needs, while overspeed torque reduction protection and other fault protection strategies may also be triggered simultaneously. If these multiple commands operate independently or are simply superimposed, command conflicts are likely to occur, or even excessive drive torque may be mistakenly output to the motor, exacerbating the overspeed. In this embodiment, the motor controller uniformly converts the multiple commands triggered in parallel into their respective requested output torque values, and forces the smallest value among them to be used as the final target drive torque, so that the motor responds with the "most conservative" torque at any given time. This ensures the timeliness of overspeed torque reduction and eliminates the mutual conflicts between multiple protection commands from a mechanism perspective, avoiding the application of excessive torque and improving the determinism and reliability of the first-level protection.

[0037] Step S500: When the real-time motor speed is greater than the second speed threshold n2 and not greater than the third speed threshold n3, the motor controller performs second-level cooperative overspeed protection for the drive motor, that is, controls the output torque of the drive motor and / or sends a gear shifting request to the vehicle controller; wherein, for vehicles equipped with a gear shifting mechanism, the motor controller obtains the gear shifting status signal of the transmission controller in real time through the CAN bus, and determines the above control method based on the mechanical connection status fed back by the gear shifting status signal. Specifically, it can be further subdivided into the following preferred embodiments: (1) Neutral condition: When the gearbox controller is in neutral state with the mechanical connection disconnected based on the shift status signal, the motor controller performs the negative torque protection function, that is, controls the drive motor to output reverse braking torque to reduce the speed, and sends the instrument panel deceleration request signal through the CAN bus to prompt the vehicle to decelerate to the preset target speed V.

[0038] Upon entering the second speed range, the overspeed is already quite severe, and simply reducing torque is insufficient to curb it; active braking is required to quickly reduce the motor speed. In neutral, the mechanical connection between the drive motor and the wheels is disengaged, so applying electromagnetic braking will not be transmitted to the wheels via the transmission gears, thus not affecting the vehicle's movement. In this embodiment, after confirming that the mechanical connection is disengaged in neutral, the motor controller instructs the drive motor to enter electromagnetic reverse drag (regenerative braking) mode, outputting reverse negative torque to convert and dissipate the motor's kinetic energy to reduce its speed. Simultaneously, a speed reduction request is sent to the instrument panel via CAN, prompting the driver to reduce the vehicle speed to the target speed V. This quickly and effectively suppresses motor overspeed without affecting the wheels or the entire vehicle, and achieves human-machine collaborative speed reduction through instrument prompts.

[0039] (2) Gear disengagement condition: When the gearbox controller is in the process of disengaging the gear based on the gear shift status signal, the motor controller blocks the negative braking request, forces the output of zero torque control command, so that the output torque of the drive motor on the mechanical transmission chain is zero, and sends a speed reduction request signal to the instrument panel to prompt the vehicle to slow down to the preset target speed V; after the gear disengagement is completed, it is processed according to the corresponding condition.

[0040] During the disengagement process, the gearbox's meshing gears are in the process of disengaging. If negative torque (braking torque) is applied at this time as if in neutral, the gears that have not yet disengaged will be subjected to additional transmission stress and "locked up," preventing the disengagement shift fork from completing the disengagement action smoothly. After determining that the disengagement process is in the disengagement stage, the motor controller blocks all negative braking requests and forces zero torque output, reducing the output stress of the drive motor on the mechanical transmission chain to zero. This eliminates the gear friction lock-up resistance caused by the application of electromagnetic negative torque. This ensures that the disengagement shift fork can smoothly complete the shifting action without additional mechanical stress, avoids electromechanical interference and jamming, and creates conditions for transitioning to neutral negative torque braking after disengagement.

[0041] (3) Gear-on condition: When the gearbox controller is determined to be neither in neutral nor in the process of disengaging gear based on the shift status signal, that is, when the drive motor is mechanically connected to the wheel via the gear position, the motor controller sends a command to the vehicle controller via the CAN bus to request to engage neutral. While waiting for the neutral engagement response, the motor controller performs the negative torque protection function and sends a speed reduction request signal to the instrument panel to prompt the vehicle to slow down to the preset target speed V.

[0042] When in gear, the drive motor is rigidly connected to the wheels via the gear position. Directly applying negative torque would cause braking force to react back to the wheels via gears, affecting the entire vehicle, and the motor would struggle to decelerate effectively from the load. Ideally, the mechanical connection should be disengaged first. However, gear shifting is managed by the transmission controller and the vehicle controller; the motor controller does not have direct authority to perform gear changes. Therefore, the motor controller proactively sends a "dimension reduction" command to the vehicle controller via the CAN bus across controller domains, requesting to shift into neutral. The vehicle controller then issues a gear shift control command to the transmission controller to facilitate shifting into neutral. While waiting for the neutral shift response, the motor controller simultaneously applies negative torque protection and prompts the instrument panel for deceleration. This proactive, cross-controller collaboration facilitates electromechanical decoupling, allowing the system to quickly enter a safe neutral state for braking, balancing motor deceleration with overall vehicle safety.

[0043] (4) Simplified platform operating conditions: This method also includes the step of identifying the electric drive topology of the vehicle; when it is identified that the current vehicle is only equipped with a single electric drive assembly, or the electric drive assembly has only a single fixed reduction gear ratio and no shifting mechanism, in the second level of cooperative overspeed protection in step S500, the motor controller omits the acquisition and analysis of the shifting status signal of the gearbox controller, bypasses the above mechanical anti-interference judgment, and directly determines the control of the output torque of the drive motor as the execution of the negative torque protection function so as to reduce the speed of the drive motor.

[0044] The neutral, disengaged, and engaged gear determinations in the second level all presuppose the existence of a gear shifting mechanism. However, the platform to which this method is applicable may only be equipped with a single electric drive assembly, or the electric drive assembly may only have a single fixed reduction gear ratio without a gear shifting mechanism. Such platforms do not have gear switching; therefore, performing gear shifting status determination would be meaningless and could lead to logic anomalies due to the inability to obtain gear shifting status signals. To address this, the method includes a pre-set electric drive topology identification step. Once the simplified platform is identified, the motor controller reconstructs the second-level determination logic during operation, skipping the acquisition and parsing of the gearbox controller's gear shifting status signal and directly using negative torque braking for speed reduction protection. This ensures that the same set of tiered overspeed protection logic is backward compatible with simplified platforms, avoiding unnecessary determinations and potential anomalies, maximizing the reuse of the existing control framework, and improving the method's platform adaptability and versatility.

[0045] Step S600: When the real-time motor speed is greater than the third speed threshold n3, the motor controller executes the third-level extreme overspeed protection logic to put the drive motor into a three-phase short circuit state to suppress the back electromotive force generated by overspeed, thereby avoiding failure problems such as uncontrolled rectification.

[0046] In a preferred embodiment of step S600, the motor controller performs an active short-circuit (ASC) protection function: controlling the power switching devices of the motor inverter, for example, simultaneously turning on the power switching devices of the three-phase upper bridge arm of the inverter, or simultaneously turning on the power switching devices of the three-phase lower bridge arm, to establish a three-phase internal short-circuit conduction loop between the three-phase windings of the drive motor; simultaneously sending a speed reduction request signal to the instrument panel to prompt the vehicle to slow down to a preset target speed V. Further, after triggering the active short-circuit protection function, the motor controller establishes a forced state lock: even if the real-time motor speed drops below the third speed threshold n3, or even below the second speed threshold n2, the aforementioned three-phase internal short-circuit conduction loop is maintained until the real-time motor speed is monitored to drop to no greater than the first speed threshold n1, at which point the active short-circuit protection function is unilaterally unlocked and exited.

[0047] When the speed exceeds n3, it is considered extreme overspeed. The back electromotive force (EMF) increases sharply with the speed, which may cause fatal failures such as uncontrolled rectification (back EMF flowing back into the DC bus, causing overvoltage). At this point, torque reduction and negative torque are insufficient to cope with the situation, and the motor energy must be immediately contained internally. At the same time, if the protection is exited with ordinary small hysteresis, the drop and rise of the speed near the threshold will cause the system to repeatedly enter and exit the short circuit state, causing violent oscillations in torque and current. The control inverter simultaneously turns on the three power switching devices of the upper arm or the three power switching devices of the lower arm, short-circuiting the three-phase windings of the motor and forming a three-phase internal short circuit loop. This consumes the back EMF energy inside the motor windings and suppresses uncontrolled rectification. A forced state lock is also established. After triggering, even if the speed drops back and crosses n3 and n2, the short circuit is maintained until it drops back to no more than n1 before unidirectional unlocking and exiting, forming a long-span asymmetric hysteresis. It not only reliably suppresses back EMF and uncontrolled rectifier under extreme overspeed conditions with three-phase short circuit, protecting the inverter and motor, but also avoids repeated switching oscillations near the threshold with hysteresis lockout that is much greater than ordinary hysteresis, making the protection process stable and reliable.

[0048] Through the graded processing of steps S100 to S600 above (see...) Figure 1 This embodiment adopts corresponding protection measures for different overspeed levels of the drive motor, which solves the overspeed problem of the drive motor and avoids the loss of power of the whole vehicle as much as possible, so as to realize intelligent and hierarchical protection for the safety of the drive motor and the whole vehicle.

[0049] Example 2 This embodiment provides a multi-drive vehicle multi-gear electric drive control device. This device can be used as a motor controller or integrated into a motor controller to implement the method described in Embodiment 1. Combined with... Figure 2 The signal transmission relationship shown indicates that the device includes a speed acquisition module, a communication protocol interaction module, a multi-level threshold determination module, and an electromechanical coordination command output module. Each module is connected to... Figure 2 The corresponding signal paths are as follows.

[0050] Speed ​​acquisition module, corresponding Figure 2 The connection path between the MCU and the drive motor is as follows: This module applies "control" to the drive motor via the MCU and receives "signal feedback" from the drive motor (such as the rotor position / speed feedback signal output by the resolver). It collects and decodes the real-time motor speed of the drive motor. When the resolver fails, this module also works with the communication protocol interaction module to reconstruct the motor speed using the vehicle speed and gear signal according to Formula 1 and Formula 2 (see the preferred embodiment of step S100 in Example 1).

[0051] Communication protocol interaction module, corresponding Figure 2 The CAN communication pathways between the motor controller and the vehicle control unit (VCU), and between the motor controller and the transmission control unit (TCU), are as follows: On one hand, this module receives downlink control commands and signals such as vehicle speed and gear position from the vehicle controller via the CAN bus, and sends uplink signals such as motor speed, temperature, and faults back to the vehicle controller; on the other hand, this module obtains information such as gear position and shift status from the transmission controller via the CAN bus. Figure 2 As shown, the transmission controller can also directly transmit this signal to the motor controller via the CAN bus, which can further shorten the transmission time when the motor controller and transmission controller are integrated in the design. This module provides the required inputs such as vehicle speed, gear, and shift status to the multi-level threshold determination module and the electromechanical coordination command output module, and carries the gear shifting request sent by the motor controller to the vehicle controller.

[0052] The multi-level threshold determination module receives the real-time motor speed output by the speed acquisition module, determines the range (n1 < n2 < n3) it is in, which is divided by the first speed threshold, the second speed threshold and the third speed threshold, and provides the determination result to the electromechanical coordination command output module to trigger the corresponding level of protection logic.

[0053] Electromechanical coordination command output module, corresponding to Figure 2 The motor controller outputs "control" commands to the drive motor, and indirectly controls gear shifting via the vehicle controller. When the real-time motor speed is greater than a second speed threshold but not greater than a third speed threshold, this module performs torque control on the drive motor based on the gear shifting status obtained from the communication protocol interaction module (e.g., outputting negative torque or zero torque commands via the "control" path from the MCU to the motor), or sends a gear shifting request to the vehicle controller. This request is then sent by the vehicle controller to the gear shift controller via the CAN bus as a "gear shifting control command," and the gear shift controller then applies "control" to the gear shifting mechanism to execute the gear shift. Figure 2The circuit connects the vehicle controller to the transmission controller and then to the shift mechanism. In other speed ranges, this module also performs corresponding outputs such as first-stage torque reduction and third-stage three-phase short circuit.

[0054] The modules described above work together to execute all steps S100 to S600 (including preferred embodiments) in Embodiment 1. For details, please refer to Embodiment 1; they will not be repeated here. Each module can be implemented using software, hardware, or a combination of both, for example, embedded in the microprocessor of the motor controller.

[0055] Example 3 This embodiment provides a new energy multi-electric drive assembly collaborative architecture system, including multiple electric drive assemblies providing power, a shifting mechanism for mechanical gear switching, and a vehicle controller, a transmission controller, and a motor controller that are interconnected and coupled. The transmission controller is configured to provide feedback on the gear position status and shifting process information of the transmission system, including neutral, disengaged, and engaged states. The motor controller is configured to execute the method described in Embodiment 1. The motor controller and transmission controller are integrated to shorten the transmission time of gear signals. The signal transmission relationships between the controllers, drive motors, and shifting mechanisms in this system are described in [reference needed]. Figure 2 As explained above, the process of each controller coordinating to execute the method described in Embodiment 1 is the same as in Embodiment 1, and will not be repeated here. With the above architecture, this system can implement graded overspeed protection for each multi-speed drive motor when multiple electric drive assemblies are working together, ensuring safety while preventing loss of vehicle power.

[0056] Example 4 This embodiment provides a non-volatile computer-readable storage medium storing computer program instructions. When the computer program instructions are loaded and executed by a microprocessor in an on-board central computing platform or motor controller, they implement the various steps of the method described in Embodiment 1 (i.e., steps S100 to S600 and various preferred embodiments). For details, please refer to Embodiment 1, which will not be repeated here.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0058] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A method for graded overspeed processing of multi-drive vehicle multi-gear drive motors, applied to a motor controller, characterized in that, The method includes: Obtain the real-time motor speed of the drive motor; The real-time motor speed is compared with a preset first speed threshold, a second speed threshold, and a third speed threshold, wherein the first speed threshold is less than the second speed threshold, and the second speed threshold is less than the third speed threshold; When the real-time motor speed is not greater than the first speed threshold, the target drive torque is output according to the control command of the vehicle controller. When the real-time motor speed is greater than the first speed threshold and not greater than the second speed threshold, the first-level torque reduction protection control logic is executed to reduce the output torque of the drive motor and suppress the real-time motor speed from continuing to rise. When the real-time motor speed is greater than the second speed threshold and not greater than the third speed threshold, a second-level cooperative overspeed protection is performed on the drive motor. The second-level cooperative overspeed protection includes: controlling the output torque of the drive motor and / or sending a gear shifting request to the vehicle controller. For vehicles equipped with a gear shifting mechanism, the motor controller obtains the gear shifting status signal of the transmission controller in real time through the controller area network bus, and determines the above control method based on the mechanical connection status fed back by the gear shifting status signal. When the real-time motor speed exceeds the third speed threshold, the third-level extreme overspeed protection logic is executed, causing the drive motor to enter a three-phase short-circuit state to suppress the back electromotive force generated by overspeed.

2. The method for graded overspeed processing of multi-drive vehicle multi-gear drive motors according to claim 1, characterized in that, When the real-time motor speed is greater than the first speed threshold and not greater than the second speed threshold and the first-level torque reduction protection control logic is executed, the motor controller synchronously receives the control command from the vehicle controller, the overspeed torque reduction protection command set by the motor controller itself, and other fault protection commands built into the motor controller; the motor controller calculates the output torque value requested by each of the above commands in real time, and selects the minimum value among the output torque values ​​as the target drive torque finally output by the drive motor.

3. The method for graded overspeed processing of multi-drive vehicle multi-gear drive motors according to claim 1, characterized in that, In the second-level cooperative overspeed protection, when the gearbox controller is determined to be in neutral with the mechanical connection disconnected based on the shift status signal, the motor controller executes the negative torque protection function and sends a speed reduction request signal to the instrument panel through the controller area network bus to prompt the vehicle to slow down to the preset target speed.

4. The method for graded overspeed processing of multi-drive vehicle multi-gear drive motors according to claim 1, characterized in that, In the second-level cooperative overspeed protection, when the gearbox controller is determined to be in the disengagement process of the disengaged gear based on the shift status signal, the motor controller blocks the negative braking request, forcibly outputs a zero torque control command, and sends a speed reduction request signal to the instrument panel to prompt the vehicle to slow down to the preset target speed.

5. The method for graded overspeed processing of multi-drive vehicle multi-gear drive motors according to claim 1, characterized in that, In the second-level cooperative overspeed protection, when it is determined based on the shift status signal that the transmission controller is neither in neutral nor in the process of disengaging, the motor controller sends a command to the vehicle controller via the controller area network bus to request to shift into neutral; while waiting for the neutral shift response, the motor controller executes the negative torque protection function and sends a speed reduction request signal to the instrument panel to prompt the vehicle to slow down to the preset target speed.

6. The method for graded overspeed processing of multi-drive vehicle multi-gear drive motors according to claim 1, characterized in that, The third-level extreme overspeed protection logic includes: the motor controller executes an active short-circuit protection function, controls the power switching devices of the motor inverter to establish a three-phase internal short-circuit conduction loop, and sends a speed reduction request signal to the instrument panel to prompt the vehicle to reduce its speed to a preset target speed; after the active short-circuit protection function is triggered, the motor controller establishes a state lock, and even if the real-time motor speed falls below the third speed threshold or even below the second speed threshold, the three-phase internal short-circuit conduction loop is maintained until the real-time motor speed falls to no more than the first speed threshold, at which point the active short-circuit protection function is exited.

7. The method for graded overspeed processing of multi-drive vehicle multi-gear drive motors according to claim 1, characterized in that, The method further includes a step of monitoring the electrical and communication anomalies of the rotary transformer that collects the real-time motor speed; when it is determined that the rotary transformer has a decoding failure or communication loss, resulting in the failure of the motor controller's speed acquisition link, the motor controller switches the speed signal source and obtains the real-time vehicle speed signal and the current gear signal fed back by the transmission controller through the controller area network bus; the motor controller converts the vehicle speed signal into wheel speed according to the pre-calibrated wheel rolling radius, and calculates the current motor speed by combining it with the pre-calibrated transmission ratio corresponding to the current gear, and uses the calculated current motor speed as the real-time motor speed; The motor controller replaces the original, now invalid, rotational speed value collected by the rotary transformer with the real-time motor speed, and compares it with the first, second, and third rotational speed thresholds.

8. The method for graded overspeed processing of multi-drive vehicle multi-gear drive motors according to claim 1, characterized in that, The method further includes a step of identifying the vehicle's electric drive topology; when it is identified that the current vehicle is only equipped with a single electric drive assembly, or the electric drive assembly does not have a shift mechanism, in the second-level cooperative overspeed protection, the motor controller omits the acquisition and parsing of the shift status signal of the transmission controller, and determines the control of the output torque of the drive motor to perform the negative torque protection function, so as to reduce the speed of the drive motor.

9. A multi-drive vehicle multi-gear electric drive motor overspeed classification treatment device, characterized in that, include: The speed acquisition module is used to acquire the real-time motor speed of the drive motor; The communication protocol interaction module is used for data interaction with the vehicle controller and the transmission controller via the controller area network bus. A multi-level threshold determination module is used to determine the interval in which the real-time motor speed is located, which is divided by a first speed threshold, a second speed threshold, and a third speed threshold, wherein the first speed threshold is less than the second speed threshold, and the second speed threshold is less than the third speed threshold; The electromechanical coordination command output module is used to control the torque of the drive motor according to the shifting state of the gearbox controller when the real-time motor speed is greater than the second speed threshold and not greater than the third speed threshold, or to send a gear shifting request to the vehicle controller. The device is configured to perform the various steps of the overspeed classification processing method for multi-drive vehicle multi-gear drive motors as described in any one of claims 1 to 8.

10. A collaborative architecture system for a new energy multi-electric drive system, characterized in that, The system includes multiple electric drive assemblies that provide power, a shift mechanism for mechanical gear switching, and a vehicle controller, a transmission controller, and a motor controller that are interconnected and coupled. The transmission controller is configured to provide feedback on the gear position status and shift process information of the transmission system. The motor controller is configured to execute the overspeed classification processing method for multi-drive vehicle multi-gear drive motors as described in any one of claims 1 to 8. The motor controller and the transmission controller are integrated to shorten the transmission time of gear signals.

11. A non-volatile computer-readable storage medium, characterized in that, It stores computer program instructions, which, when loaded and executed by a microprocessor in an on-board computing platform or motor controller, implement each step of the overspeed classification processing method for multi-drive vehicle multi-gear drive motors as described in any one of claims 1 to 8.

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