Motor control method and device and vehicle

Abstract

The embodiment of the application provides a motor control method and device and a vehicle, through executing the method, the motor fly vehicle prevention process can be periodically executed in the vehicle driving process; in each process: when it is determined that the motor speed and torque meet the first condition, the motor fly vehicle prevention function is activated; the torque limiting value is calculated based on the motor torque, the motor speed change rate and the inertia of the drive wheel system, and the motor speed is limited based on the torque limiting value; when it is determined that the motor speed meets the second condition, the motor fly vehicle prevention function is closed. Through periodically executing the motor fly vehicle prevention process to control the motor, in each period, after the motor fly vehicle prevention function is activated, the motor is subjected to the torque limiting operation through the calculated torque limiting value to implement the motor fly vehicle prevention processing, the rapid response of the torque control can be realized, the processing efficiency is improved, the frequency of the problem that the vehicle shakes due to the excessively high motor speed is reduced, and the user driving experience is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor control, and particularly relates to a motor control method and device and a vehicle. BACKGROUND

[0002] Currently, some motor controllers prevent the motor from flying by controlling the motor torque output to be 0Nm when the motor speed exceeds the maximum speed of the motor, and limiting the torque output to control the motor speed. Under this control mode, the vehicle cannot be inhibited in the transient slipping working condition, the response is slow, and the vehicle may be out of control, and the subjective feeling of the driver is poor. Another control mode is to calculate the motor speed change rate, and when the motor speed change rate exceeds a threshold, the torque is limited to control the motor speed. In this mode, the motor speed fluctuates constantly during the torque is limited, that is, the motor torque changes constantly, and the vehicle shakes. SUMMARY

[0003] Embodiments of the present application provide a motor control method and device and a vehicle, and the motor torque can be limited based on the motor speed by the method to prevent the motor from flying.

[0004] In a first aspect, the embodiments of the present application provide a motor control method, including: periodically executing a motor flying prevention process during vehicle driving; wherein the motor flying prevention process includes: activating a motor flying prevention function when it is determined that the motor speed and torque meet a first condition; calculating a torque limit value based on the motor torque, the motor speed change rate and the inertia of the drive wheel system, and limiting the motor speed based on the torque limit value; and closing the motor flying prevention function when it is determined that the motor speed meets a second condition.

[0005] In a possible implementation, the determination that the motor speed and torque meet the first condition includes: when it is identified that the vehicle switches to the forward gear, if it is determined that the actual motor speed is greater than a first target speed, and the motor request torque is greater than a first torque, it is determined that the motor speed and torque meet the first condition.

[0006] In a possible implementation, the determination that the motor speed and torque meet the first condition includes: when it is identified that the vehicle switches to the reverse gear, if it is determined that the actual motor speed is greater than a second target speed, and the motor request torque is greater than a second torque, it is determined that the motor speed and torque meet the first condition.

[0007] In a possible implementation, the calculation of the torque limit value based on the motor torque, the motor speed change rate and the inertia of the drive system includes: calculating a drive system flying torque value according to the motor speed change rate and the inertia of the drive system; and calculating the torque limit value by subtracting the drive system flying torque value from the motor torque.

[0008] In a possible implementation, the limiting the motor rotating speed based on the torque limit value comprises: reducing the actual motor torque by the torque limit value; matching a corresponding target PID parameter based on a rotating speed difference between the target rotating speed and the actual rotating speed of the motor; and dynamically adjusting the motor torque based on the target PID parameter.

[0009] In a possible implementation, the rotating speed difference between the different target rotating speeds and the different actual rotating speeds of the motor is divided into a plurality of levels in advance; and the corresponding PID parameters are configured based on the rotating speed differences of the plurality of levels in advance.

[0010] In a possible implementation, the determining that the rotating speed of the motor satisfies the second condition comprises: when an absolute value of the rotating speed difference between the actual rotating speed of the motor and the reference rotating speed is less than a preset rotating speed difference, determining that the rotating speed of the motor satisfies the second condition.

[0011] In a possible implementation, after the anti-motor flying function is closed, the anti-motor flying process further comprises: restoring the torque limit value of the motor, and clearing the integral of the PID controller.

[0012] In a second aspect, the embodiments of the present application further provide a motor control device, which comprises: a processor and a memory, the memory is used to store at least one instruction, the instruction is loaded and executed by the processor, and the motor control method provided in the first aspect is realized.

[0013] In a third aspect, the embodiments of the present application provide a vehicle, which can comprise the motor control device provided in the second aspect.

[0014] Through the above technical solution, the motor is controlled by periodically executing the anti-motor flying process. In each cycle, the anti-motor flying process can be performed on the motor after the anti-motor flying function is activated, and the motor is limited in torque by the torque limit value calculated to realize the anti-motor flying process, so that the rapid response of the torque control can be realized, the processing efficiency is improved, the frequency of the problem of vehicle shaking caused by the high rotating speed of the motor is reduced, and the user driving experience is improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Figure 1 The basic flowchart of the motor control method provided by an embodiment of the present application is shown in the figure.

[0017] Figure 2 A motor control specific flowchart is provided for an embodiment of the present application;

[0018] Figure 3 A motor control device structure schematic diagram is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions and advantages of embodiments of the present application clearer, the technical solutions in embodiments of the present application will be described clearly and completely below with reference to the drawings in embodiments of the present application. Obviously, the described embodiments are some but not all of embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by persons of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0020] Figure 1 A motor control method basic flowchart is provided for an embodiment of the present application.

[0021] Referring to Figure 1 The motor control method can include:

[0022] The anti-motor runaway flow is periodically executed during vehicle driving;

[0023] The anti-motor runaway flow includes:

[0024] S101: When it is determined that the motor speed and torque meet the first condition, activate the anti-motor runaway function.

[0025] S102: Calculate the torque limit value based on the motor torque, speed change rate and inertia of the drive train, and limit the motor speed based on the torque limit value.

[0026] S103: When it is determined that the motor speed meets the second condition, close the anti-motor runaway function.

[0027] By periodically executing the anti-motor runaway flow, the motor speed and torque can be obtained to determine whether the motor meets the first condition, and the anti-motor runaway function is activated when the first condition is met to achieve fast function activation. After the function is activated, the torque limit value is calculated based on the motor torque, speed change rate and inertia of the drive train, and the torque is limited to achieve fast processing of torque control, and the function is closed after the motor speed meets the second condition. By periodically executing the above flow, the anti-motor runaway processing of the motor can be achieved, the fast response of torque control can be achieved, the processing efficiency can be improved, the problem of vehicle shaking caused by high motor speed can be reduced, and the user driving experience can be improved.

[0028] Figure 2A specific flow chart of motor control is provided for an embodiment of the present application.

[0029] Referring to Figure 2 The specific flow can be Figure 1 The specific implementation steps of the method shown in

[0030] During vehicle driving, it can be determined how to determine whether the speed and torque of the motor meet the first condition by acquiring the current gear information of the vehicle.

[0031] S201: Determine the gear information of the vehicle, and if it is in the forward gear (D gear), execute S202a, or if it is currently in the reverse gear (R gear), execute S202b.

[0032] S202a: Determine whether the actual speed of the motor is greater than the first target speed and the motor request torque is greater than the first torque, and if so, execute S203, or if not, control the current flow to end.

[0033] S202b: Determine whether the actual speed of the motor is greater than the second target speed and the motor request torque is greater than the second torque, and if so, execute S203, or if not, control the current flow to end.

[0034] In some embodiments, determining that the speed and torque of the motor meet the first condition comprises:

[0035] When it is identified that the vehicle switches to the forward gear, if the actual speed of the motor is greater than the first target speed and the motor request torque is greater than the first torque at the same time, it is determined that the speed and torque of the motor meet the first condition.

[0036] In some embodiments, determining that the speed and torque of the motor meet the first condition comprises:

[0037] When it is identified that the vehicle switches to the reverse gear, if the actual speed of the motor is greater than the second target speed and the motor request torque is greater than the second torque at the same time, it is determined that the speed and torque of the motor meet the first condition.

[0038] In some embodiments, if the actual speed of the motor is not greater than the second target speed and / or the motor request torque is not greater than the second torque, it is determined that the speed and torque of the motor do not meet the first condition.

[0039] In some embodiments, at the beginning of each anti-wheel-spin process, the first target speed and the second target speed to be applied in the current process can be calculated first, and the first torque and the second torque can be set. The first target speed or the second target speed can be calculated based on a reference speed. Specifically, the reference speed can be calculated based on the non-driving wheel speed, the tire radius, the speed ratio of the reducer, and the gear signal to obtain the corresponding reference speed of the motor. Further, the first target speed and the second target speed can be calculated by amplifying the reference speed by a corresponding preset ratio. It should be noted that the preset ratio for calculating the first target speed and the second target speed respectively can be set based on the vehicle motor parameters and user demand, which is not limited in the present application.

[0040] S203: activate the anti-wheel-spin function.

[0041] When the speed and torque of the motor meet the first condition, the anti-wheel-spin function of the motor can be activated.

[0042] S204: calculate a torque limit value based on the torque, the speed change rate of the motor, and the inertia of the drive wheel system.

[0043] In some embodiments, the specific calculation method of the torque limit value includes: calculating a drive system wheel-spin torque value according to the speed change rate and the inertia of the drive system; and calculating the torque limit value by subtracting the drive system wheel-spin torque value from the torque of the motor.

[0044] In one embodiment, calculating a drive system wheel-spin torque value according to the speed change rate and the inertia of the drive system includes:

[0045] 1. Calculate the motor shaft angular acceleration (unit: rad / s^2) = speed change rate (unit: rpm / s) 2Pi / 60;

[0046] 2. Calculate the inertia of the drive system. According to the speed ratio relationship, the inertia of the tire, drive shaft, differential, and gear set is calculated to the equivalent inertia of the drive system on the motor shaft.

[0047] 3. Calculate the drive system wheel-spin torque value according to the motor shaft angular acceleration and the equivalent inertia of the drive system, and limit the maximum / minimum value.

[0048] Subtracting the drive system wheel-spin torque value from the torque of the motor to obtain the torque limit value includes:

[0049] According to the current actual torque of the motor minus the drive system wheel-spin torque value, the current road load torque is estimated to obtain a feedforward torque value before closed-loop control.

[0050] In some embodiments, after the torque limit is calculated, the motor speed can be limited based on the torque limit value. In one implementation, limiting the motor speed based on the torque limit value comprises:

[0051] S205: reducing the actual motor torque by the torque limit value.

[0052] In some embodiments, the torque that causes the motor speed to increase can be calculated according to the actual motor torque, the speed change rate, and the inertia of the drive train, and the calculated torque can be used as the torque reduction value to control the motor, thereby achieving feedforward control of the motor torque.

[0053] S206: matching the target PID parameter corresponding to the speed difference between the target speed and the actual speed of the motor.

[0054] In some embodiments, the speed difference between different target speeds and different actual speeds of the motor is divided into multiple levels in advance, and the corresponding PID parameters are configured based on the multiple levels of speed difference in advance.

[0055] In some embodiments, the speed difference between the target speed and the actual speed of the motor can be calculated, and the PID parameter corresponding to the level of the speed difference can be matched according to the corresponding level of the speed difference.

[0056] S207: dynamically adjusting the motor torque based on the target PID parameter.

[0057] In some embodiments, the motor can be dynamically PID controlled based on the PID parameter corresponding to the level of the speed difference, to suppress the motor speed and prevent the motor from flying.

[0058] S208: determining whether the absolute value of the speed difference between the actual speed and the reference speed of the motor is less than a preset speed difference, if yes, executing S209, if no, returning to S204.

[0059] S209: closing the function of preventing the motor from flying.

[0060] In some embodiments, when the absolute value of the speed difference between the actual speed and the reference speed of the motor is less than the preset speed difference, it is determined that the speed of the motor satisfies the second condition, and then S209 can be continued.

[0061] In some embodiments, when the absolute value of the speed difference between the actual speed and the reference speed of the motor is not less than the preset speed difference, it is determined that the speed of the motor does not currently satisfy the second condition, and the motor needs to be continuously suppressed, and the subsequent steps are returned to S204 for execution until the speed of the motor satisfies the second condition, and the function of preventing the motor from flying is closed.

[0062] In some embodiments, after the anti-motor runaway flow is closed, the torque limit value of the motor is restored, and the integral of the PID controller is cleared. By clearing the integral of the anti-saturation integrator, the integral term is prevented from over-adjusting the PID controller.

[0063] In some embodiments, periodically performing the anti-motor runaway flow can include performing the anti-motor runaway flow every 1 ms, so that fast response to motor anti-runaway processing can be achieved while reducing torque fluctuations.

[0064] The motor control method provided by the embodiments of the present application can perform feedforward control and dynamic PID control on the motor, which not only achieves fast response but also reduces torque fluctuations, maximizes the torque output of the motor, improves the driving experience of the user, and ensures the safe driving of the customer in this scenario.

[0065] Figure 3 The motor control device provided by an embodiment of the present application is shown in the structural diagram.

[0066] Referring to Figure 3 The motor control device can include a processor 301 and a memory 302, and the memory 302 is used to store at least one instruction, which is loaded and executed by the processor 301 to implement the motor control method provided by any embodiment of the present application.

[0067] The embodiments of the present application also provide a vehicle, which can include Figure 3 The motor control device provided by the embodiments shown, and the vehicle can also implement the motor control method provided by any embodiment of the present application based on the motor control device.

[0068] It should be noted that the terminal involved in the embodiments of the present application can include but is not limited to a personal computer (PC), a personal digital assistant (PDA), a wireless handheld device, a tablet computer, a mobile phone, an MP3 player, an MP4 player, etc.

[0069] It can be understood that the application can be an application program (nativeApp) installed on the terminal, or can also be a web program (webApp) of a browser on the terminal, and the embodiments of the present application do not limit this.

[0070] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0071] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. For example, the described device embodiment is merely illustrative. For example, the division of the units is only a logical function division. There can be another division manner for the actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0072] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purposes of the embodiments.

[0073] In addition, each functional unit in the various embodiments of the present application can be integrated in one processing unit, or each unit can be a physically separate unit, or two or more units can be integrated in one unit. The integrated unit can be implemented in the form of hardware, or in the form of hardware plus software function units.

[0074] The integrated unit implemented in the form of software function units can be stored in a computer readable storage medium. The software function unit stored in the storage medium includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (Processor) to execute some steps of the method described in the various embodiments of the present application. The aforementioned storage medium includes a variety of storage media that can store program codes, such as a U disk, a mobile hard disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk or an optical disk, etc.

[0075] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

[0076] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of controlling an electric machine, characterized by, The method comprises: During driving of the vehicle, a motor flywheel prevention process is periodically executed; The motor flywheel prevention process comprises: When it is determined that the motor speed and torque meet a first condition, a motor flywheel prevention function is activated; A torque limit value is calculated based on the motor torque, speed change rate and drive system inertia, and the motor speed is limited based on the torque limit value; When it is determined that the motor speed meets a second condition, the motor flywheel prevention function is closed; The calculation of the torque limit value based on the motor torque, speed change rate and drive system inertia comprises: A drive system flywheel torque value is calculated according to the speed change rate and the drive system inertia; The torque limit value is obtained by subtracting the current actual torque of the motor from the drive system flywheel torque value; The limiting of the motor speed based on the torque limit value comprises: The motor actual torque is reduced by the torque limit value; A speed difference between a target speed and an actual speed of the motor is matched with a corresponding target PID parameter; The motor torque is dynamically adjusted based on the target PID parameter.

2. The method of claim 1, wherein, The determination that the motor speed and torque meet the first condition comprises: When it is determined that the vehicle switches to a forward gear, if it is determined that the motor actual speed is greater than a first target speed and the motor request torque is greater than a first torque, it is determined that the motor speed and torque meet the first condition.

3. The method of claim 1, wherein, The determination that the motor speed and torque meet the first condition comprises: When it is determined that the vehicle switches to a reverse gear, if it is determined that the motor actual speed is greater than a second target speed and the motor request torque is greater than a second torque, it is determined that the motor speed and torque meet the first condition.

4. The method of claim 1, wherein, The speed difference between different target speeds and different actual speeds of the motor is divided into multiple levels in advance; The corresponding PID parameters are configured based on the multiple levels of speed difference in advance.

5. The method of claim 1, wherein, The determination that the motor speed meets the second condition comprises: When the absolute value of the speed difference between the motor actual speed and a reference speed is less than a preset speed difference, it is determined that the motor speed meets the second condition.

6. The method of claim 1, wherein, After the motor flywheel prevention function is closed, the motor flywheel prevention process further comprises: The torque limit value of the motor is restored, and the integral of the PID controller is cleared.

7. An electric motor control device characterized by comprising: The device comprises: A processor and a memory, the memory being used to store at least one instruction, the instruction being loaded and executed by the processor to implement the motor control method according to any one of claims 1-6.

8. A vehicle characterized by comprising: The vehicle comprises the motor control device according to claim 7.

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