Motor torque control method, device and vehicle

Abstract

The application relates to a motor torque control method and device and a vehicle, and the method comprises the following steps: obtaining a motor torque request value, wherein the motor torque request value is obtained when both a motor request mode and a motor current operation mode are torque control modes; if the motor torque request value is smaller than a preset torque threshold value, determining a motor actual torque value and a motor actual back electromotive force; if the motor actual torque value and the motor actual back electromotive force are smaller than a preset determination threshold value, controlling an IGBT (insulated gate bipolar transistor) of the motor to be turned off, so that the motor is in a zero torque state. According to the actual torque and the actual back electromotive force of the motor, the IGBT is actively turned off in the embodiment of the application, zero torque control of the motor is realized, the switching loss of the IGBT under the zero torque working condition can be effectively reduced, and the energy efficiency and the cruising range of the vehicle are improved.

Description

TECHNICAL FIELD

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

[0002] There are various motor zero torque control scenarios for new energy vehicles, for example, when free sliding and no sliding energy recovery is required, the motor is in a zero torque control state, and for P13 architecture hybrid power vehicles, when the engine is directly driven by the vehicle and the P1 motor is not required to generate power, the P1 motor is often in a zero torque control state.

[0003] Currently, motor zero torque is mainly achieved by measuring the control current value of the motor zero torque on the dynamometer bench, using the current value as the zero torque control current command value, using permanent magnet synchronous motor vector control and pulse width adjustment to generate PWM (pulse width modulation) signals to drive the conduction and turn-off of insulated gate bipolar transistors (IGBT), where IGBT is the control hardware of the motor controller.

[0004] However, for the above-mentioned motor zero torque control scenarios, IGBT switching is driven by signals generated by current values in any scenario. This single control of IGBT switching results in significant IGBT on and off losses, which is not conducive to vehicle energy saving and further affects the user's driving experience. SUMMARY

[0005] One of the purposes of the present application is to provide a motor torque control method to solve the problem of complex operation in the prior art vehicle steering dependent on the driver's operation; the second purpose is to provide a motor torque control device; and the third purpose is to provide a vehicle.

[0006] To achieve the above-mentioned purposes, the technical solutions adopted by the present application are as follows:

[0007] A motor torque control method, the method comprising:

[0008] obtaining a motor torque request value, wherein the motor torque request value is obtained when both the motor request mode and the motor current operating mode are torque control modes;

[0009] If the motor torque request value is less than a preset torque threshold, determining the motor actual torque value and the motor actual back electromotive force;

[0010] If the motor actual torque value and the motor actual back electromotive force are less than a preset determination threshold, controlling the IGBT of the motor to turn off, so that the motor is in a zero torque state.

[0011] Optionally, the determining the motor actual torque value and the motor actual back electromotive force, if the motor torque request value is less than a preset torque threshold, comprises:

[0012] If the motor torque request value is less than a preset torque threshold, collecting three-phase feedback currents of the motor;

[0013] Converting the three-phase feedback currents into two-phase feedback currents;

[0014] Based on the two-phase feedback currents, looking up a table to obtain an equivalent inductance and a rotor permanent magnet flux pre-written into the motor;

[0015] Determining the motor actual torque value according to the equivalent inductance and the rotor permanent magnet flux.

[0016] Optionally, the determining the motor actual torque value and the motor actual back electromotive force, if the motor torque request value is less than a preset torque threshold, comprises:

[0017] If the motor torque request value is less than a preset torque threshold, obtaining a current actual rotating speed of the motor;

[0018] Determining the motor actual back electromotive force according to the current actual rotating speed of the motor.

[0019] Optionally, the controlling the IGBT of the motor to be off to make the motor in a zero-torque state, if the motor actual torque value and the motor actual back electromotive force are less than a preset determination threshold, comprises:

[0020] Obtaining a current bus voltage actual value, and comparing the motor actual back electromotive force with the bus voltage actual value;

[0021] If an absolute value difference between the motor actual torque value and the motor torque request value is less than a preset threshold, and the motor actual back electromotive force is greater than the bus voltage actual value, controlling the IGBT of the motor to be off to make the motor in a zero-torque state.

[0022] Optionally, after the controlling the IGBT of the motor to be off, if the motor actual torque value and the motor actual back electromotive force are less than a preset determination threshold, the method further comprises:

[0023] If the absolute value difference between the motor actual torque value and the motor torque request value is greater than or equal to the preset threshold, or the motor actual back electromotive force is less than or equal to the bus voltage actual value, driving the IGBT of the motor to be off through the three-phase feedback currents of the motor.

[0024] A motor torque control device, comprising:

[0025] The acquisition request value module is configured to acquire a motor torque request value, wherein the motor torque request value is obtained when both the motor request mode and the motor current operation mode are torque control modes.

[0026] The determination actual value module is configured to determine an actual motor torque value and an actual motor back electromotive force if the motor torque request value is less than a preset torque threshold value.

[0027] The control turn-off module is configured to control the turn-off of the IGBT of the motor to make the motor in a zero torque state if the actual motor torque value and the actual motor back electromotive force are less than a preset determination threshold value.

[0028] Optionally, the determination actual value module comprises:

[0029] The acquisition sub-module is configured to acquire three-phase feedback currents of the motor if the motor torque request value is less than the preset torque threshold value.

[0030] The conversion sub-module is configured to convert the three-phase feedback currents into two-phase feedback currents.

[0031] The first acquisition sub-module is configured to obtain equivalent inductance and rotor permanent magnet flux of the motor by table lookup based on the two-phase feedback currents.

[0032] The first determination sub-module is configured to determine the actual motor torque value according to the equivalent inductance and the rotor permanent magnet flux.

[0033] Optionally, the determination actual value module comprises:

[0034] The second acquisition sub-module is configured to acquire a current actual motor speed if the motor torque request value is less than the preset torque threshold value.

[0035] The second determination sub-module is configured to determine the actual motor back electromotive force according to the current actual motor speed.

[0036] Optionally, the control turn-off module comprises:

[0037] The comparison sub-module is configured to acquire a current bus voltage actual value, and compare the actual motor back electromotive force with the bus voltage actual value.

[0038] The first control sub-module is configured to control the turn-off of the IGBT of the motor to make the motor in a zero torque state if the absolute value difference between the actual motor torque value and the motor torque request value is less than a preset threshold value, and the actual motor back electromotive force is greater than the bus voltage actual value.

[0039] Optionally, the control turn-off module further comprises

[0040] A second control submodule is configured to drive the gate turn-off bipolar transistor of the motor to be off through three-phase feedback currents of the motor, if the difference between the actual motor torque value and the absolute value of the motor torque request value is greater than or equal to a preset threshold value, or the actual motor back electromotive force is less than or equal to the actual bus voltage value.

[0041] The present application has the following advantages:

[0042] The motor torque control method provided by the embodiment of the present application comprises the following steps: obtaining a motor torque request value; determining an actual motor torque value and an actual motor back electromotive force, if the motor torque request value is less than a preset torque threshold value; and controlling a gate turn-off bipolar transistor of the motor to be off, if the actual motor torque value and the actual motor back electromotive force are less than a preset determination threshold value, so that the motor is in a zero torque state. The embodiment of the present application sets a determination condition of the motor torque value, actively controls the IGBT switch to be off when the actual motor torque value meets the requirement, realizes zero torque control of the motor, and directly turns off the IGBT in the scene requiring zero torque control by using the determination condition of the motor torque value. The active IGBT turn-off can effectively reduce the switching loss of the IGBT under such working conditions, improve the energy efficiency and the cruising range of the vehicle, and further improve the driving experience of the user. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 FIG. 1 is one of step flowcharts of a motor torque control method provided by the embodiment of the present application;

[0044] Figure 2 FIG. 2 is one of step flowcharts of the motor torque control method provided by the embodiment of the present application; Figure 1 FIG. 3 is one of step flowcharts of the motor torque control method provided by the embodiment of the present application;

[0045] Figure 3 FIG. 4 is one of step flowcharts of the motor torque control method provided by the embodiment of the present application; Figure 1 FIG. 5 is one of step flowcharts of the motor torque control method provided by the embodiment of the present application;

[0046] Figure 4 FIG. 6 is a structural schematic diagram of a motor torque control device provided by the embodiment of the present application; Figure 1

[0047] FIG. 7 is a flowchart of a motor torque control method provided by the embodiment of the present application; Figure 5

[0048] FIG. 8 is a structural block diagram of a motor torque control device provided by the embodiment of the present application. Figure 6

[0049] Figure 7

[0050] ​​Reference signs: 1-engine, 2-clutch, 3-generator, 4-towing motor, 5-motor controller, 6-power battery, 7-main relay, 8-reducer, 9-wheel. DETAILED DESCRIPTION

[0051] Other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure of the present specification. The present application can also be implemented or applied by means of other different specific embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application. It should be understood that the preferred embodiments are only for illustrating the present application, but not for limiting the protection scope of the present application.

[0052] The present application is to solve the IGBT switching loss problem of the new energy vehicle in the zero torque control scene, so as to reduce the switching loss in the zero torque control, save the power battery energy, and improve the vehicle mileage. Referring to Figure 5 , Figure 5 The structure schematic diagram of the motor torque control device provided by the embodiment of the present application is shown, wherein the P13 configuration new energy vehicle power device is taken as an example of one of the embodiments of the present application, and the device mainly includes: an engine 1, a power battery 6, a main relay 7, a motor controller 5, a generator 3, a towing motor 4, a clutch 2, a reducer 8, and a wheel 9. The engine 1 is mechanically connected with the generator 3 and connected with the reducer 8 through the clutch 2, and the towing motor 4 is directly connected to the reducer 8. The power battery 6, the main relay 7, and the motor controller 5 are directly connected to the high-voltage direct-current bus. At the same time, the motor controller 5 is connected to the vehicle CAN network through the CAN line. The new energy vehicle of this configuration has three driving modes: pure electric mode, series mode, and parallel mode. In the pure electric mode, the engine 1 and the generator 3 are in the shutdown state, and the clutch 2 is in the open state. The energy flows from the power battery 6 to the towing motor 4 through the motor controller 5, and then drives the vehicle to run through the wheel 9. In the series mode, the clutch 2 is in the open state, the engine 1 drives the generator 3 to generate electricity, which is used for charging the power battery 6 and driving the towing motor 4. The vehicle is only driven to run by the towing motor 4. In the parallel mode, the clutch 2 is in the engaged state, the engine 1 directly drives the vehicle, and the towing motor 4 can drive the vehicle. The generator 3 can generate electricity or rotate with the engine 1.

[0053] Referring to Figure 1 , one of the step flowcharts of the motor torque control method provided by the embodiment of the present application is shown, and the method can include:

[0054] In step 101, a motor torque request value is obtained, wherein the motor torque request value is obtained when the motor request mode and the motor current operation mode are both torque control modes.

[0055] In the embodiment of the present application, the motor controller obtains the request mode of the motor from the vehicle controller through the CAN network, and obtains the current operation mode of the motor, and controls the conversion of the current operation mode of the motor according to the request mode of the motor from the vehicle controller, when the request mode of the motor and the current operation mode of the motor are both torque control modes, the motor controller obtains the torque request value of the motor in the torque control mode.

[0056] It should be noted that in the torque control mode, the motor is controlled by the current loop, the torque is proportional to the current, the motor controller obtains the actual current of the motor, and determines the actual torque of the motor, compares the actual torque value with the required torque, and adjusts the current of the motor in real time to achieve the required torque.

[0057] Specifically, the motor controller obtains the request mode of the motor from the vehicle controller through the CAN network, and obtains the current operation mode of the motor, and judges whether the request mode of the motor from the vehicle controller and the current operation mode of the motor are both torque control modes, if so, the motor controller obtains the torque request value of the motor in the torque control mode.

[0058] In step 102, if the torque request value of the motor is less than the preset torque threshold, the actual torque value of the motor and the actual back electromotive force of the motor are determined.

[0059] In the embodiment of the present application, if the torque request value of the motor is less than the preset torque threshold, the torque of the motor needs to be adjusted, and the motor controller first determines the actual torque value of the motor and the actual back electromotive force of the motor, so as to determine the actual torque of the motor according to the actual torque value of the motor and the actual back electromotive force of the motor, and further determine the torque.

[0060] It should be noted that the motor controller obtains the torque request value Tref of the motor from the vehicle controller through the CAN network, and judges whether the absolute value |Tref| of the torque request value of the motor is less than the preset threshold, wherein the preset threshold is a preset judgment index, and the default value in the embodiment is 3Nm. Of course, the above is only a specific example, and the embodiment is not limited to this. The preset threshold can be set according to the actual control requirement, which will not be described here.

[0061] Specifically, the motor controller can obtain three-phase feedback currents IU, IV and IW of the motor, estimate the actual torque Test of the motor through an electromagnetic torque formula, obtain the current bus voltage actual value Vdc and the current actual speed n of the motor, calculate the actual back electromotive force e of the motor according to the current actual speed, and refer to the specific discussion below, which will not be repeated here.

[0062] In step 103, if the actual torque value of the motor and the actual back electromotive force of the motor are less than the preset determination threshold, the gate turn-off bipolar transistor of the motor is controlled to be turned off, so that the motor is in a zero torque state.

[0063] In the embodiment of the application, the gate turn-off bipolar transistor of the motor is controlled to be turned off according to the determination condition of the active gate turn-off bipolar transistor IGBT for realizing zero torque control, so that the motor is in a zero torque state. Specifically, if the actual torque value of the motor and the actual back electromotive force of the motor are less than the preset determination threshold, the gate turn-off bipolar transistor of the motor is controlled to be turned off, so that the motor is in a zero torque state.

[0064] It should be noted that whether the difference between the absolute value |Test| of the actual torque value of the motor and the absolute value |Tref| of the torque request value of the motor is less than the preset determination threshold, wherein the threshold 2 is a calibration quantity and the default value is 3 Nm, and whether the current back electromotive force e of the motor is less than the current bus voltage actual value V dc , of course, the above preset determination threshold is only a specific example, and the embodiment is not limited to this. The determination threshold can be set according to the actual control requirement, which will not be repeated here. If the determination conditions are met, the power tube IGBT is controlled to be turned off, and the zero torque control of the motor is realized.

[0065] The motor torque control method provided in the embodiment of the application obtains the torque request value of the motor, determines the actual torque value of the motor and the actual back electromotive force of the motor if the torque request value of the motor is less than the preset torque threshold, controls the gate turn-off bipolar transistor of the motor to be turned off if the actual torque value of the motor and the actual back electromotive force of the motor are less than the preset determination threshold, and makes the motor in a zero torque state. In the embodiment of the application, the determination condition of the torque value of the motor is set, the IGBT switch is actively controlled to be turned off when the actual torque value of the motor meets the requirement, the zero torque control of the motor is realized, the IGBT is directly turned off in the scene requiring zero torque control by using the determination condition of the torque value of the motor, the switching loss of the IGBT under such working conditions can be effectively reduced by actively turning off the IGBT, the energy efficiency and the cruising range of the vehicle are improved, and the driving experience of the user is further improved.

[0066] Further, referring to Figure 2 , Figure 2 is Figure 1The step 102 of the motor torque control method provided by the embodiment of the present application is shown in one of the method flowcharts, and the step 102 comprises:

[0067] In step 201, if the motor torque request value is less than the preset torque threshold value, three-phase feedback currents of the motor are collected.

[0068] Specifically, in order to obtain the code for determining the condition for implementing zero torque control through active braking based on the actual motor torque value and the actual motor back electromotive force, the actual motor torque value and the actual motor back electromotive force need to be determined first. Therefore, the actual motor torque value is determined first.

[0069] Specifically, if the motor torque request value is less than the preset torque threshold value, three-phase feedback currents IU, IV and IW of the motor are collected, so as to estimate the current actual torque Test of the motor based on the three-phase feedback currents.

[0070] In step 202, the three-phase feedback currents are converted into two-phase feedback currents.

[0071] In the embodiment of the present application, the current sensor collects three-phase current feedback values IU, IV and IW of the motor. First, the three-phase feedback currents IU, IV and IW are converted into two-phase feedback currents Ia and Ib through Clark transformation, and the conversion formula is as follows:

[0072]

[0073] Wherein, IU, IV and IW are three-phase feedback currents, the conversion matrix is set by collecting a certain number of samples in advance, and Ia and Ib are the converted two-phase feedback currents.

[0074] Secondly, the actual position angle of the rotor is collected through the resolver, and then the two-phase currents Ia and Ib are converted into dq coordinate system currents Id and Iq through Park transformation, and the conversion formula is as follows: α β d q

[0075]

[0076] In step 203, the equivalent inductance and the rotor permanent magnet flux of the motor are obtained by looking up the table based on the two-phase feedback currents.

[0077] In the embodiment of the present application, the equivalent inductance Ld, Lq and the rotor permanent magnet flux ψ of the motor are obtained by looking up the two-dimensional table based on the converted two-phase feedback currents Id and Iq. d q d q ​​​​​​​​f wherein, it is to be noted that the equivalent inductance of the motor dq axis L d , L q and the rotor permanent magnet flux linkage ψ f The two-dimensional table of Id, Iq is calculated by motor bench calibration test, and is written in the motor controller in advance.

[0078] Step 204, according to the equivalent inductance and the rotor permanent magnet flux linkage, the actual torque value of the motor is determined.

[0079] Specifically, according to the dq axis current Id, Iq, the equivalent inductance of the motor dq axis L d , L q and the rotor permanent magnet flux linkage ψ f The actual torque of the motor is calculated, and the formula is:

[0080]

[0081] Wherein, P is the number of pole pairs of the motor, and the specific value is not limited here.

[0082] Further, referring to Figure 3 , Figure 3 is Figure 1 The method flow chart two of step 102 of the motor torque control method provided by the embodiment of the application, if the motor torque request value is less than the preset torque threshold, the actual torque value of the motor and the actual back electromotive force of the motor are determined, and further comprising:

[0083] Step 205, if the motor torque request value is less than the preset torque threshold, the current actual speed of the motor is obtained.

[0084] Step 206, according to the current actual speed of the motor, the actual back electromotive force of the motor is determined.

[0085] Specifically, in the above steps 205 to 206, if the motor torque request value is less than the preset torque threshold, the current bus voltage actual value V dc and the current actual speed of the motor n are collected and obtained, and the current actual back electromotive force e of the motor is calculated;

[0086] Wherein, the calculation formula of the actual back electromotive force of the motor is:

[0087]

[0088] Wherein, ψ f is the rotor permanent magnet flux linkage, and n is the current actual speed of the motor.

[0089] In the embodiment, the motor controller controls the power tube IGBT to be turned off to realize the zero torque control of the motor by judging whether the determination condition of the current back electromotive force e of the motor and the actual value Vdc of the current bus voltage is met.

[0090] Further, referring to Figure 4 , Figure 4 is Figure 1 The method flow chart of step 103 of the motor torque control method provided by the embodiment of the application, if the actual torque value of the motor and the actual back electromotive force of the motor are less than the preset determination threshold, the IGBT of the motor is controlled to be turned off to make the motor in the zero torque state, comprising:

[0091] Step 301, the actual value of the current bus voltage is obtained, and the actual back electromotive force of the motor and the actual value of the bus voltage are compared.

[0092] Step 302, if the absolute value difference between the actual torque value of the motor and the torque request value of the motor is less than the preset threshold, and the actual back electromotive force of the motor is greater than the actual value of the bus voltage, the IGBT of the motor is controlled to be turned off to make the motor in the zero torque state.

[0093] Specifically, the determination condition of the IGBT of the motor being turned off in the embodiment is that the absolute value difference between the actual torque value of the motor and the torque request value of the motor is less than the preset threshold, and the actual back electromotive force of the motor is greater than the actual value of the bus voltage, so that the zero torque control of the engine GM and the traction motor TM is realized by actively turning off the IGBT in the free running and engine direct drive working conditions of the new energy vehicle, that is, the switching loss of the IGBT in such working conditions can be effectively reduced by actively turning off the IGBT, and the energy efficiency and the cruising range of the vehicle are improved.

[0094] Specifically, if the actual torque value of the motor and the actual back electromotive force of the motor are less than the preset determination threshold, the IGBT of the motor is controlled to be turned off to make the motor in the zero torque state in step 103, which can further comprise:

[0095] If the absolute value difference between the actual torque value of the motor and the torque request value of the motor is greater than or equal to the preset threshold, or the actual back electromotive force of the motor is less than or equal to the actual value of the bus voltage, the IGBT of the motor is driven to be turned off by the three-phase feedback current of the motor.

[0096] It should be noted that if the determination condition is not met, but the motor zero torque control is actually needed, the IGBT is driven to be turned on or off by the dq axis current closed loop control of the motor controller, that is, the IGBT is driven to be turned off by the three-phase feedback current of the motor to realize the motor zero torque control, so as to meet the user and vehicle driving requirements.

[0097] Compared with the prior art, the embodiment of the application determines the actual motor torque value and the actual motor back electromotive force if the motor torque request value is less than the preset torque threshold, and controls the IGBT of the motor to be turned off so that the motor is in a zero torque state. The embodiment of the application actively controls the IGBT to be turned off when the actual motor torque value meets the requirement by setting the determination condition of the motor torque value, thereby realizing zero torque control of the motor. The determination condition of the motor torque value is used to directly turn off the IGBT in the scenario requiring zero torque control, and the active turning off of the IGBT can effectively reduce the switching loss of the IGBT in such working conditions, improve the energy efficiency and cruising range of the vehicle, and further improve the driving experience of the user.

[0098] In order for those skilled in the art to more clearly understand the overall process of the motor torque control method disclosed in the above embodiments of the application, the flowchart of the motor torque control method is described by taking Figure 6 as an example.

[0099] Step 401: Obtain the motor request mode and the current motor operating mode.

[0100] Specifically, the motor controller obtains the motor request mode of the vehicle controller from the CAN network and obtains the current motor operating mode.

[0101] Step 402: Determine whether both are torque control modes.

[0102] In this embodiment, the motor controller determines whether the motor request mode of the vehicle controller and the current motor operating mode are both torque control modes. If so, step 403 is entered to obtain the motor torque request value when the motor request mode and the current motor operating mode are both torque control modes.

[0103] Step 403: Obtain the motor torque request value.

[0104] Step 404: Determine whether the motor torque request value is less than the preset torque threshold.

[0105] In this embodiment, the code based on the determination condition of the active IGBT for realizing zero torque control based on the actual motor torque value and the actual motor back electromotive force needs to first determine the actual motor torque value and the actual motor back electromotive force. First, the actual motor torque value is determined, and it is determined whether the motor torque request value is less than the preset torque threshold.

[0106] Step 405: Collect the three-phase feedback current of the motor to determine the actual motor torque value.

[0107] Specifically, if the motor torque request value is less than the preset torque threshold, three-phase feedback currents IU, IV and IW of the motor are collected, so that the current actual torque Test of the motor is estimated based on the three-phase feedback currents.

[0108] In step 406, it is judged whether the absolute difference between the motor actual torque value and the motor torque request value is less than a preset threshold.

[0109] In this embodiment, it is judged whether the absolute difference between the motor actual torque value and the motor torque request value is less than a preset threshold. If the motor torque request value is less than the preset torque threshold, step 407 is entered, and the current bus voltage actual value V dc and the current actual speed n of the motor are acquired, and the current actual back electromotive force e of the motor is calculated.

[0110] In step 407, the current actual speed of the motor is acquired, and the actual back electromotive force of the motor is calculated.

[0111] In step 408, it is judged whether the actual back electromotive force of the motor is less than the bus voltage actual value.

[0112] In this embodiment, it is judged whether the determination condition of the current back electromotive force e of the motor and the current bus voltage actual value Vdc is met. If yes, step 409 is entered, and the motor controller controls the IGBT to be turned off, so as to realize the zero torque control of the motor.

[0113] In step 409, the IGBT of the motor is controlled to be turned off.

[0114] The embodiment of the application sets the determination condition of the motor torque value. When the actual torque value of the motor meets the requirement, the IGBT switch is actively controlled to be turned off, so as to realize the zero torque control of the motor. The determination condition of the motor torque value is used to directly turn off the IGBT in the scene requiring zero torque control. The active turning off of the IGBT can effectively reduce the switching loss of the IGBT in such working condition, improve the energy efficiency and the cruising range of the vehicle, and further improve the driving experience of the user.

[0115] Referring to Figure 7 , a structure schematic diagram of a motor torque control device provided by an embodiment of the application is shown. The device can include:

[0116] The request value acquisition module 501 is configured to acquire a motor torque request value. The motor torque request value is obtained when the motor request mode and the current operation mode of the motor are both torque control modes.

[0117] The actual value determination module 502 is configured to determine the actual torque value of the motor and the actual back electromotive force of the motor if the motor torque request value is less than a preset torque threshold.

[0118] The control-off module 503 is configured to control the IGBT of the motor to be off if the actual torque value of the motor and the actual back electromotive force of the motor are less than a preset determination threshold, so that the motor is in a zero-torque state.

[0119] Optionally, the determination actual value module 502 comprises:

[0120] The acquisition submodule is configured to acquire three-phase feedback currents of the motor if the motor torque request value is less than a preset torque threshold.

[0121] The conversion submodule is configured to convert the three-phase feedback currents into two-phase feedback currents.

[0122] The first acquisition submodule is configured to obtain, based on the two-phase feedback currents, equivalent inductance and rotor permanent magnet flux pre-written into the motor by table lookup.

[0123] The first determination submodule is configured to determine the actual torque value of the motor according to the equivalent inductance and the rotor permanent magnet flux.

[0124] Optionally, the determination actual value module 502 further comprises:

[0125] The second acquisition submodule is configured to acquire a current actual rotating speed of the motor if the motor torque request value is less than a preset torque threshold.

[0126] The second determination submodule is configured to determine the actual back electromotive force of the motor according to the current actual rotating speed of the motor.

[0127] Optionally, the control-off module 503 comprises:

[0128] The comparison submodule is configured to acquire a current bus voltage actual value, and compare the actual back electromotive force of the motor with the bus voltage actual value.

[0129] The first control submodule is configured to control the IGBT of the motor to be off if the absolute value difference between the actual torque value of the motor and the motor torque request value is less than a preset threshold, and the actual back electromotive force of the motor is greater than the bus voltage actual value, so that the motor is in a zero-torque state.

[0130] Optionally, the control-off module 503 further comprises

[0131] The second control submodule is configured to drive the IGBT of the motor to be off through three-phase feedback currents of the motor if the absolute value difference between the actual torque value of the motor and the motor torque request value is greater than or equal to a preset threshold, or the actual back electromotive force of the motor is less than or equal to the bus voltage actual value.

[0132] The specific implementation method of the motor torque control device provided in the embodiment can refer to the content described in the motor torque control method provided in the embodiment, which will not be repeated here.

[0133] The motor torque control device provided in the embodiment determines the actual motor torque value and the actual motor back electromotive force if the motor torque request value is less than the preset torque threshold, and controls the IGBT of the motor to be turned off so that the motor is in a zero torque state. The embodiment sets the determination condition of the motor torque value, actively controls the IGBT to be turned off when the actual motor torque value meets the requirement, realizes the zero torque control of the motor, and directly turns off the IGBT in the scene requiring zero torque control by using the determination condition of the motor torque value. The active turning off of the IGBT can effectively reduce the switching loss of the IGBT in such working conditions, improve the energy efficiency and the cruising range of the vehicle, and further improve the driving experience of the user.

[0134] Based on the motor torque control method described above, the embodiment further provides a vehicle, which comprises the motor torque control device in the above steps, and is used to execute the motor torque control method described in the above steps.

[0135] It can be understood that the vehicle shown in the present application can be various types of vehicles, and the motor torque control method proposed in the present application can be applied to these various types of vehicles.

[0136] It should be noted that, in the present text, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0137] Each embodiment in the present specification is described in a related manner, and the same or similar parts between each embodiment can be referred to each other. Each embodiment focuses on the difference from other embodiments. Especially, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the related parts can refer to the part of the method embodiment.

[0138] The above merely provides the preferred embodiments of the application, and not intended to limit the protection scope of the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall fall within the protection scope of the application.

Claims

1. A method of motor torque control, characterized by, The method comprises: acquiring a motor torque request value, wherein the motor torque request value is obtained when both a motor request mode and a motor current operation mode are torque control modes; if the motor torque request value is less than a preset torque threshold, determining a motor actual torque value and a motor actual back electromotive force, comprising: if the motor torque request value is less than the preset torque threshold, collecting three-phase feedback currents of the motor, acquiring a current actual speed of the motor, and determining the motor actual torque value and the motor actual back electromotive force according to the three-phase feedback currents and the current actual speed of the motor; if the motor actual torque value and the motor actual back electromotive force are less than a preset determination threshold, controlling an insulated gate bipolar transistor of the motor to be turned off so that the motor is in a zero torque state, comprising: acquiring a current bus voltage actual value, comparing the motor actual back electromotive force with the bus voltage actual value, if an absolute value difference between the motor actual torque value and the motor torque request value is less than a preset threshold and the motor actual back electromotive force is greater than the bus voltage actual value, controlling the insulated gate bipolar transistor of the motor to be turned off, and if the absolute value difference between the motor actual torque value and the motor torque request value is greater than or equal to the preset threshold or the motor actual back electromotive force is less than or equal to the bus voltage actual value, driving the insulated gate bipolar transistor of the motor to be turned off through the three-phase feedback currents of the motor so that the motor is in the zero torque state.

2. The method of claim 1, wherein, The method comprises: if the motor torque request value is less than the preset torque threshold, collecting three-phase feedback currents of the motor; converting the three-phase feedback currents into two-phase feedback currents; based on the two-phase feedback currents, looking up a table to obtain an equivalent inductance and a rotor permanent magnet flux previously written into the motor; determining the motor actual torque value according to the equivalent inductance and the rotor permanent magnet flux.

3. The method of claim 2, wherein, The method comprises: if the motor torque request value is less than the preset torque threshold, acquiring a current actual speed of the motor; determining the motor actual back electromotive force according to the current actual speed of the motor.

4. An electric motor torque control device characterized by comprising: The device comprises: an acquisition request value module, configured to acquire a motor torque request value, wherein the motor torque request value is obtained when both a motor request mode and a motor current operation mode are torque control modes; a determination actual value module, configured to, if the motor torque request value is less than a preset torque threshold, determine a motor actual torque value and a motor actual back electromotive force, comprising: if the motor torque request value is less than the preset torque threshold, collecting three-phase feedback currents of the motor, acquiring a current actual speed of the motor, and determining the motor actual torque value and the motor actual back electromotive force according to the three-phase feedback currents and the current actual speed of the motor; The control module is configured to control the IGBT of the motor to be turned off if the actual torque value of the motor and the actual back electromotive force of the motor are less than a preset determination threshold, so that the motor is in a zero torque state. The control module includes: a comparison submodule configured to obtain an actual bus voltage value, and compare the actual back electromotive force of the motor with the actual bus voltage value; a first control submodule configured to control the IGBT of the motor to be turned off if the absolute value of the difference between the actual torque value of the motor and the torque request value of the motor is less than a preset threshold, and the actual back electromotive force of the motor is greater than the actual bus voltage value; and a second control submodule configured to control the IGBT of the motor to be turned off by driving the IGBT of the motor through three-phase feedback currents of the motor if the absolute value of the difference between the actual torque value of the motor and the torque request value of the motor is greater than or equal to the preset threshold, or the actual back electromotive force of the motor is less than or equal to the actual bus voltage value, so that the motor is in a zero torque state.

5. The electric motor torque control device of claim 4, wherein, The determination module includes: a collection submodule configured to collect three-phase feedback currents of the motor if the torque request value of the motor is less than a preset torque threshold; a conversion submodule configured to convert the three-phase feedback currents into two-phase feedback currents; a first acquisition submodule configured to obtain, based on the two-phase feedback currents, equivalent inductance and rotor permanent magnet flux previously written into the motor by table lookup; a first determination submodule configured to determine the actual torque value of the motor according to the equivalent inductance and the rotor permanent magnet flux.

6. The electric motor torque control device of claim 4, wherein The determination module includes: a second acquisition submodule configured to obtain a current actual rotating speed of the motor if the torque request value of the motor is less than the preset torque threshold; a second determination submodule configured to determine the actual back electromotive force of the motor according to the current actual rotating speed of the motor.

7. A vehicle characterized by comprising: The motor torque control device includes the motor torque control device according to any one of claims 4 to 6.

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