阅读说明：本技术 车用电机的扭矩监控方法、装置以及汽车 (Torque monitoring method and device for vehicle motor and vehicle ) 是由 龚道清 叶甜春 王云 任广辉 薛静 卢苗 詹圣益 于 2021-01-22 设计创作，主要内容包括：本发明涉及一种车用电机的扭矩监控方法、装置以及汽车,该方法包括：监测电机的转速,并判断电机的转速是否小于预先设定的转速阈值,如果小于,则基于电机的电流模型,根据电机的电流信号和转子位置信号,计算电机的估算扭矩；如果不小于,则基于电机的功率模型,根据电机矢量控制产生的PWM信号、电机控制器输入的直流母线电压信号和电机的驱动相电流信号,计算电机的估算扭矩；计算估算扭矩与电机的请求扭矩的差值,判断差值是否大于预先设定的差值阈值,如果大于,则输出电机发生扭矩违规信号,并触发相应的安全措施；如果不大于,则输出主控电机扭矩正常信号。上述方法可以提高监测的精准度。(The invention relates to a torque monitoring method and device of a vehicle motor and a vehicle, wherein the method comprises the following steps: monitoring the rotating speed of the motor, judging whether the rotating speed of the motor is smaller than a preset rotating speed threshold value or not, and if so, calculating the estimated torque of the motor according to a current signal and a rotor position signal of the motor based on a current model of the motor; if not, calculating the estimated torque of the motor according to a PWM signal generated by motor vector control, a direct current bus voltage signal input by a motor controller and a driving phase current signal of the motor based on a power model of the motor; calculating a difference value between the estimated torque and the requested torque of the motor, judging whether the difference value is larger than a preset difference value threshold value, if so, outputting a torque violation signal of the motor, and triggering a corresponding safety measure; and if not, outputting a normal torque signal of the main control motor. The method can improve the monitoring accuracy.)

1. A torque monitoring method of a vehicle motor, characterized by comprising:

monitoring the rotating speed of the motor, judging whether the rotating speed of the motor is less than a preset rotating speed threshold value or not,

if the current signal is smaller than the rotor position signal, calculating the estimated torque of the motor according to the current signal and the rotor position signal of the motor based on the current model of the motor;

if the current value is not less than the preset value, calculating the estimated torque of the motor according to a PWM signal generated by motor vector control, a direct current bus voltage signal input by a motor controller and a driving phase current signal of the motor based on a power model of the motor;

calculating a difference between the estimated torque and a requested torque of the motor, judging whether the difference is greater than a preset difference threshold value,

if the torque is larger than the preset torque, outputting a torque violation signal of the motor, and triggering a corresponding safety measure;

and if not, outputting the torque normal signal of the main control motor.

2. The method for monitoring torque of a motor for a vehicle according to claim 1, wherein said calculating an estimated torque of the motor based on the current signal of the motor and the rotor position signal based on the current model of the motor comprises:

acquiring a driving phase current signal and a motor rotor position signal of a main driving motor, and converting three-phase alternating current into d-axis current and q-axis current through coordinate transformation;

calculating a current vector and an included angle between the current vector and a motor rotor rotating coordinate system according to the d-axis current and the q-axis current;

calculating the estimated output electromagnetic torque of the motor according to the inductance, the magnetic flux and the pole pair number of the motor per se and a motor output torque equation;

and calculating the estimated torque of the motor according to the electromagnetic torque and the friction torque on the output shaft of the motor.

3. The torque monitoring method of a vehicle motor according to claim 2, wherein in the acquiring of the driving phase current signal of the main driving motor and the motor rotor position signal and converting the three-phase alternating current into the d-axis current and the q-axis current through the coordinate transformation, the three-phase alternating current is converted into the d-axis current and the q-axis current by using a first formula, wherein the first formula is:

in the formula I_a，I_b，I_cRespectively representing the acquired U-phase, V-phase and W-phase currents; θ represents the motor rotor position; i is_dAnd I_qRepresenting d-axis current and q-axis current, respectively.

4. The torque monitoring method of a vehicle motor according to claim 2, wherein in the calculating of the current vector and the angle between the current vector and the motor rotor rotation coordinate system based on the d-axis current and the q-axis current, the current vector is calculated using a second formula and the angle δ between the current vector and the motor rotor rotation coordinate system is calculated using a third formula, the second formula being:

the third formula is:

δ＝arctan(I_q/I_d)

in the formula, Is represents a current vector; i is_dAnd I_qRespectively representing d-axis current and q-axis current; delta denotes the angle between the current vector and the rotating coordinate system of the motor rotor.

5. The torque monitoring method of the motor for a vehicle according to claim 2, wherein the motor output torque equation is:

wherein p represents the number of pole pairs of the motor, lambda_mRepresenting the motor rotor flux, L_dAnd L_qRespectively representing d and q-axis inductances, T, of the motor_eleRepresenting an estimated output electromagnetic torque of the electric machine;

in the calculating of the estimated torque of the motor based on the electromagnetic torque and the friction torque on the output shaft of the motor, a fourth formula is adopted to calculate the estimated torque of the motor, wherein the fourth formula is as follows:

in the formula, T_mechRepresenting an estimated torque of the electric machine; t is_friThe friction torque on the output shaft of the motor is represented by T obtained according to a function relation related to the rotating speed of the motor_fri＝f(ω)。

6. The method for monitoring torque of a vehicle motor according to claim 1, wherein the calculating an estimated torque of the motor based on a power model of the motor based on a PWM signal generated by a motor vector control, a dc bus voltage signal inputted from a motor controller, and a driving phase current signal of the motor comprises:

collecting PWM signals generated by the motor vector control and direct-current bus voltage signals input by a motor controller;

reconstructing a three-phase alternating current voltage signal output by a motor controller according to the three-phase bridge arm switching state and the bus voltage;

calculating the output power of the motor controller of the motor according to the three-phase alternating voltage signal and the driving phase current signal of the motor;

calculating active power of a motor controller and a motor system according to the output power;

and calculating the estimated torque of the motor according to the active power of the motor controller and the motor and the rotating speed of the motor.

7. The method for monitoring torque of an electric motor for vehicle according to claim 6, wherein a fifth formula is used to reconstruct the three-phase ac voltage signal output by the motor controller from the three-phase bridge arm switching state and the bus voltage, wherein the fifth formula is:

in the formula, S1, S2 and S3 respectively represent the given instantaneous phase voltage duty ratio of the three power tubes of the upper half bridge in one period; vdc represents the voltage on the dc bus; the una, Ubn and Ucn respectively represent the reconstructed U-phase, V-phase and W-phase voltages.

8. The torque monitoring method of a motor for a vehicle according to claim 6, wherein in the calculating of the output power of the motor controller based on the three-phase ac voltage signal and the driving phase current signal of the motor, a sixth formula is used to calculate the output power, wherein the sixth formula is:

P_int＝U_an·I_a+U_bn·I_b+U_cnI_c

in the formula, P_intRepresenting the calculated motor controller output power; u shape_an、U_bn、U_cnRespectively representing the reconstructed U-phase, V-phase and W-phase voltages; i is_a、I_b、I_cRespectively representing the acquired U-phase, V-phase and W-phase currents of the main drive motor;

in the calculating the estimated torque of the motor according to the active power of the motor controller and the motor and the rotating speed of the motor, a seventh formula is adopted to calculate the estimated torque of the motor, wherein the seventh formula is as follows:

T_mech＝P_intη/ω

in the formula, T_mechRepresenting an estimated torque of the electric machine; eta represents the system efficiency of the motor controller and the motor system; ω represents the motor speed.

9. A torque monitoring device of a motor for a vehicle, characterized by comprising:

the motor rotating speed monitoring unit is used for monitoring the rotating speed of the motor and judging whether the rotating speed of the motor is smaller than a preset rotating speed threshold value or not;

a first torque calculation unit for calculating an estimated torque of the motor according to a current signal and a rotor position signal of the motor based on a current model of the motor if the rotational speed of the motor is less than the rotational speed threshold;

the second torque calculation unit is used for calculating the estimated torque of the motor according to a PWM signal generated by motor vector control, a direct-current bus voltage signal input by a motor controller and a driving phase current signal of the motor based on a power model of the motor if the rotating speed of the motor is not less than the rotating speed threshold;

a torque safety judgment unit for calculating a difference between the estimated torque and a requested torque of the motor, judging whether the difference is greater than a preset difference threshold,

if the torque is larger than the preset torque, outputting a torque violation signal of the motor, and triggering a corresponding safety measure;

and if not, outputting the torque normal signal of the main control motor.

10. A vehicle comprising a processor, a memory, and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the method for monitoring torque of a vehicle motor according to any one of claims 1 to 8 when executing the computer program.

Technical Field

The invention relates to the technical field of motors, in particular to a torque monitoring method and device for a vehicle motor and an automobile.

Background

With the rapid and mass popularization of new energy automobiles, the safety problem is more and more prominent. For a pure electric vehicle, the electric machine is the only torque output device. The abnormal torque output of the driving motor may cause unexpected acceleration or unexpected deceleration of the vehicle, thereby possibly causing car accidents and having great safety hazards. Therefore, the output torque of the motor needs to be monitored safely for safety.

At present, most of motor controllers with the functions of monitoring actual output torque and meeting functional safety requirements are provided, and torque safety in functional safety is realized by comparing the output torque of a motor with the torque requested by a vehicle controller, wherein the output is considered to be normal in a certain range, otherwise, an abnormity affecting safety is considered to occur. The torque sensor is not arranged on the automobile main drive system, so that the actual output torque needs to be estimated through an algorithm. However, if the accuracy of the estimated torque is not high, the vehicle is easily shut down unexpectedly, and after the unexpected shut down, the vehicle is restarted to be operated, so that the user experience is poor.

In summary, in order to ensure safety, a torque monitoring scheme meeting functional safety requirements needs to be designed; on the other hand, in order to prevent the false triggering of the shutdown, the actual output torque needs to be accurately estimated, so that the false triggering of the unexpected shutdown is avoided while the safety is ensured.

Disclosure of Invention

Accordingly, it is necessary to provide a torque monitoring method and apparatus for a vehicle motor, and a vehicle, which are directed to the problem that the output torque of the motor cannot be accurately estimated in the prior art when torque monitoring of the vehicle motor is performed.

A torque monitoring method of a vehicle motor, the torque monitoring method comprising:

monitoring the rotating speed of the motor, judging whether the rotating speed of the motor is less than a preset rotating speed threshold value or not,

if the current signal is smaller than the rotor position signal, calculating the estimated torque of the motor according to the current signal and the rotor position signal of the motor based on the current model of the motor;

if the current value is not less than the preset value, calculating the estimated torque of the motor according to a PWM signal generated by motor vector control, a direct current bus voltage signal input by a motor controller and a driving phase current signal of the motor based on a power model of the motor;

calculating a difference between the estimated torque and a requested torque of the motor, judging whether the difference is greater than a preset difference threshold value,

if the torque is larger than the preset torque, outputting a torque violation signal of the motor, and triggering a corresponding safety measure;

and if not, outputting the torque normal signal of the main control motor.

In one embodiment, the calculating an estimated torque of the motor based on the current signal of the motor and the rotor position signal based on the current model of the motor comprises:

acquiring a driving phase current signal and a motor rotor position signal of a main driving motor, and converting three-phase alternating current into d-axis current and q-axis current through coordinate transformation;

calculating a current vector and an included angle between the current vector and a motor rotor rotating coordinate system according to the d-axis current and the q-axis current;

calculating the estimated output electromagnetic torque of the motor according to the inductance, the magnetic flux and the pole pair number of the motor per se and a motor output torque equation;

and calculating the estimated torque of the motor according to the electromagnetic torque and the friction torque on the output shaft of the motor.

In one embodiment, in the step of acquiring a driving phase current signal and a motor rotor position signal of a main driving motor and converting three-phase alternating current into d-axis current and q-axis current through coordinate transformation, a first formula is adopted to convert the three-phase alternating current into the d-axis current and the q-axis current, wherein the first formula is as follows:

in the formula I_a，I_b，I_cRespectively representing the acquired U-phase, V-phase and W-phase currents; θ represents the motor rotor position; i is_dAnd I_qRepresenting d-axis current and q-axis current, respectively.

In one embodiment, in the calculating of the current vector and the included angle between the current vector and the motor rotor rotation coordinate system according to the d-axis current and the q-axis current, a second formula is used to calculate the current vector and a third formula is used to calculate the included angle δ between the current vector and the motor rotor rotation coordinate system, where the second formula is:

the third formula is:

δ＝arctan(I_q/I_d)

in the formula, Is represents a current vector; i is_dAnd I_qRespectively representing d-axis current and q-axis current; delta denotes the angle between the current vector and the rotating coordinate system of the motor rotor.

In one embodiment, the motor output torque equation is:

wherein p represents the number of pole pairs of the motor, lambda_mRepresenting the motor rotor flux, L_dAnd L_qRespectively representing d and q-axis inductances, T, of the motor_eleRepresenting an estimated output electromagnetic torque of the electric machine;

in the calculating of the estimated torque of the motor based on the electromagnetic torque and the friction torque on the output shaft of the motor, a fourth formula is adopted to calculate the estimated torque of the motor, wherein the fourth formula is as follows:

in the formula, T_mechRepresenting an estimated torque of the electric machine; t is_friThe friction torque on the output shaft of the motor is represented by T obtained according to a function relation related to the rotating speed of the motor_fri＝f(ω)。

In one embodiment, the calculating an estimated torque of the motor according to a PWM signal generated by a motor vector control, a dc bus voltage signal input by a motor controller, and a driving phase current signal of the motor based on a power model of the motor includes:

collecting PWM signals generated by the motor vector control and direct-current bus voltage signals input by a motor controller;

reconstructing a three-phase alternating current voltage signal output by a motor controller according to the three-phase bridge arm switching state and the bus voltage;

calculating the output power of the motor controller of the motor according to the three-phase alternating voltage signal and the driving phase current signal of the motor;

calculating active power of a motor controller and a motor system according to the output power;

and calculating the estimated torque of the motor according to the active power of the motor controller and the motor and the rotating speed of the motor.

In one embodiment, in reconstructing the three-phase ac voltage signal output by the motor controller according to the three-phase bridge arm switching state and the bus voltage, a fifth formula is adopted to reconstruct the three-phase ac voltage signal output by the motor controller, where the fifth formula is:

in the formula, S₁、S₂、S₃Respectively representing the given instantaneous phase voltage duty ratios of the three power tubes of the upper half bridge in one period; v_dcRepresenting the voltage on the dc bus; u shape_an、U_bn、U_cnThe reconstructed U-phase, V-phase and W-phase voltages are shown, respectively.

In one embodiment, in the calculating the output power of the motor controller according to the three-phase alternating voltage signal and the driving phase current signal of the motor, a sixth formula is adopted to calculate the output power, wherein the sixth formula is as follows:

P_int＝U_an·I_a+U_bn·I_b+U_cn·I_c

in the formula, P_intRepresenting the calculated motor controller output power; u shape_an、U_bn、U_cnRespectively representing the reconstructed U-phase, V-phase and W-phase voltages; i is_a、I_b、I_cRespectively representing the acquired U-phase, V-phase and W-phase currents of the main drive motor;

in the calculating the estimated torque of the motor according to the active power of the motor controller and the motor and the rotating speed of the motor, a seventh formula is adopted to calculate the estimated torque of the motor, wherein the seventh formula is as follows:

T_mech＝P_intη/ω

in the formula, T_mechRepresenting an estimated torque of the electric machine; eta represents the system efficiency of the motor controller and the motor system; ω represents the motor speed.

A torque monitoring device of a vehicle motor, the torque monitoring device comprising:

the motor rotating speed monitoring unit is used for monitoring the rotating speed of the motor and judging whether the rotating speed of the motor is smaller than a preset rotating speed threshold value or not;

a first torque calculation unit for calculating an estimated torque of the motor according to a current signal and a rotor position signal of the motor based on a current model of the motor if the rotational speed of the motor is less than the rotational speed threshold;

the second torque calculation unit is used for calculating the estimated torque of the motor according to a PWM signal generated by motor vector control, a direct-current bus voltage signal input by a motor controller and a driving phase current signal of the motor based on a power model of the motor if the rotating speed of the motor is not less than the rotating speed threshold;

a torque safety judgment unit for calculating a difference between the estimated torque and a requested torque of the motor, judging whether the difference is greater than a preset difference threshold,

if the torque is larger than the preset torque, outputting a torque violation signal of the motor, and triggering a corresponding safety measure;

and if not, outputting the torque normal signal of the main control motor.

A vehicle comprising a processor, a memory, a computer program stored on said memory and operable on said processor, said processor implementing the steps of the method for monitoring torque of a vehicle electric machine as described above when executing said computer program

According to the torque monitoring method and device for the vehicle motor and the vehicle, the torque is estimated by judging the rotating speed of the motor and adopting a method of combining a current model and a power model, namely when the rotating speed of the motor is lower than a preset rotating speed threshold value, the torque is estimated by adopting the current model; the current model realizes accurate estimation of torque through carrying out isomerism on a torque equation, and completely meets the requirement of software diversity in functional safety; when the rotating speed of the motor is higher than a preset rotating speed threshold value, torque estimation is carried out by adopting a power model; the power model realizes phase voltage reconstruction by acquiring and outputting PWM, and reduces material cost and complexity of related circuits. Therefore, the high torque estimation precision is ensured in the whole working rotating speed range of the motor, namely the actual output torque of the motor used by the torque monitoring part is always a torque value with high precision, and the working condition of false triggering of switching-off caused by low torque estimation precision is reduced. Therefore, the driving experience of the user is further improved while the safety is ensured.

Drawings

FIG. 1 is a flow chart of a method for torque monitoring of a vehicle motor according to one embodiment;

FIG. 2 is another flow chart of a method for monitoring torque of a vehicle motor according to one embodiment;

FIG. 3 is a flow chart of a method for torque monitoring of a vehicle motor for calculating an estimated torque of the motor based on a current model of the motor in one embodiment;

FIG. 4 is a flow chart of a method for torque monitoring of a vehicle motor to calculate an estimated torque of the motor based on a power model of the motor in one embodiment;

fig. 5 is a block diagram showing a torque monitoring device of a vehicle motor according to an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1 and 2, in one embodiment, a torque monitoring method for a vehicle motor is provided, which may specifically include the following steps:

step 101, monitoring the rotating speed of the motor, and judging whether the rotating speed of the motor is smaller than a preset rotating speed threshold value.

The rotating speed of the motor can be acquired in real time through the speed sensor. Also, the rotational speed threshold may be set based on the experience of the technician.

And step 1011, if the current signal is smaller than the rotor position signal, calculating the estimated torque of the motor according to the current signal of the motor and the rotor position signal based on the current model of the motor.

In the embodiment, the current model acquires a driving phase current signal and a motor rotor position signal of a main driving motor, and then converts three-phase alternating current into a current vector and an included angle between the current vector and a motor rotor rotating coordinate system through coordinate transformation; and calculating the estimated output electromagnetic torque of the main drive motor according to the inductance, the magnetic flux and the pole pair number of the main drive motor and a motor output torque equation, and combining the friction torque on the output shaft of the motor to obtain the final actual output torque of the motor.

And 1012, if the current is not less than the preset value, calculating the estimated torque of the motor according to the PWM signal generated by the motor vector control, the direct-current bus voltage signal input by the motor controller and the driving phase current signal of the motor based on the power model of the motor.

In this embodiment, the power model reconstructs a three-phase ac voltage signal output by the motor controller according to a PWM signal generated by motor vector control and a dc bus voltage signal input by the motor controller and a three-phase bridge arm switching state and a bus voltage, calculates an output power of the motor controller based on the three-phase ac voltage signal and a driving phase current signal of the main drive motor, calculates active powers of the motor controller and the main drive motor system using the output power of the motor controller, and calculates an actual output torque of the motor using the reconstructed active power of the motor controller and the main drive motor system and a rotation speed of the motor.

Step 102, calculating a difference value between the estimated torque and the requested torque of the motor, judging whether the difference value is larger than a preset difference value threshold value,

the requested torque may be an indicated torque output by a controller (e.g., a vehicle controller VCU) of the vehicle.

Step 1021, if the torque is larger than the preset torque limit value, outputting a torque violation signal of the motor, and triggering a corresponding safety measure;

and 1022, if the torque is not larger than the preset torque, outputting a main control motor torque normal signal.

In the implementation, the difference calculation is carried out by using the requested torque and the torque obtained by actual estimation, whether the difference value exceeds a safety range or not is judged, if the difference value exceeds the safety range, the torque violation is considered, and corresponding safety measures are taken; and if the safety range is not exceeded, the system is considered to be normally operated.

The method adopts a method of combining a current model and a power model to estimate the torque by judging the rotating speed of the motor, namely when the rotating speed of the motor is lower than a preset rotating speed threshold value, the current model is adopted to estimate the torque; the current model realizes accurate estimation of torque through carrying out isomerism on a torque equation, and completely meets the requirement of software diversity in functional safety; when the rotating speed of the motor is higher than a preset rotating speed threshold value, torque estimation is carried out by adopting a power model; the power model realizes phase voltage reconstruction by acquiring and outputting PWM, and reduces material cost and complexity of related circuits. Therefore, the high torque estimation precision is ensured in the whole working rotating speed range of the motor, namely the actual output torque of the motor used by the torque monitoring part is always a torque value with high precision, and the working condition of false triggering of switching-off caused by low torque estimation precision is reduced. Therefore, the driving experience of the user is further improved while the safety is ensured.

In some implementations, as shown in fig. 3, the step 1011 may include:

step 1011a, acquiring a driving phase current signal and a motor rotor position signal of a main driving motor, and converting three-phase alternating current into d-axis current and q-axis current through coordinate transformation;

the three-phase alternating current is converted into d-axis current and q-axis current for torque control on a d-axis and a q-axis through coordinate transformation, and the formula is as follows:

in the formula I_a，I_b，I_cRespectively representing the acquired U-phase, V-phase and W-phase currents; θ represents the motor rotor position; id and Iq are eachRepresenting the d-axis current and the q-axis current.

Step 1011b, calculating a current vector is and an included angle delta between the current vector is and a motor rotor rotating coordinate system according to the d-axis current and the q-axis current;

the formula for calculating the current vector is as follows:

the formula for calculating the included angle between the rotating coordinate systems of the motor rotor is as follows:

δ＝arctan(I_q/I_d)

in the formula, Is represents a current vector; id and Iq represent d-axis current and q-axis current, respectively; delta denotes the angle between the current vector and the rotating coordinate system of the motor rotor.

Step 1011c, calculating the estimated output electromagnetic torque of the motor according to the inductance, the magnetic flux and the pole pair number of the motor per se and the motor output torque equation;

the output torque equation of the motor is as follows:

wherein p represents the number of pole pairs of the motor, lambda_mRepresenting the motor rotor flux, L_dAnd L_qRespectively representing d and q-axis inductances, T, of the motor_eleRepresenting the estimated output electromagnetic torque of the motor.

And step 1011d, calculating the estimated torque of the motor according to the electromagnetic torque and the friction torque on the output shaft of the motor.

The electromagnetic torque is combined with the friction torque on the output shaft of the motor, and the estimated torque of the motor is obtained by adopting the following formula:

in the formula, Tmech represents an estimated torque of the motor finally calculated by combining the electromagnetic torque and the friction torque;

the friction torque on the output shaft of the motor is obtained according to the following relation:

T_fri＝f(ω)

in the formula, the friction torque on the output shaft of the motor is obtained according to a function relation related to the rotating speed of the motor.

In some implementations, as shown in fig. 4, the step 1012 may include:

step 1012a, collecting a PWM signal generated by motor vector control and a direct current bus voltage signal input by a motor controller;

step 1012b, reconstructing a three-phase alternating current voltage signal output by the motor controller according to the three-phase bridge arm switching state and the bus voltage;

the method comprises the following steps of reconstructing a three-phase alternating voltage signal output by a motor controller according to a three-phase bridge arm switching state and bus voltage by adopting the following formula:

in the formula, S₁、S₂、S₃Respectively representing the given instantaneous phase voltage duty ratios of the three power tubes of the upper half bridge in one period Ts; vdc represents the voltage on the dc bus; u shape_an、U_bn、U_cnThe reconstructed U-phase, V-phase and W-phase voltages are shown, respectively.

Step 1012c, calculating the output power of the motor controller of the motor according to the three-phase alternating voltage signal and the driving phase current signal of the motor;

the method comprises the following steps of calculating the output power of a motor controller based on a three-phase alternating current voltage signal and a collected driving phase current signal of a main driving motor according to the following formula:

P_int＝U_an·I_a+U_bn·I_b+U_cn·I_cP_Int＝U_an·I_a+U_bn·I_b+U_cn·I_c

in the formula of U_an、U_bn、U_cnRespectively representing the reconstructed U-phase, V-phase and W-phase voltages; i is_a、I_b、I_cRespectively representing the acquired U-phase, V-phase and W-phase currents of the main drive motor; p_intRepresenting the calculated motor controller output power.

Step 1012c, calculating active power of the motor controller and the motor according to the output power;

step 1012d, calculating an estimated torque of the motor according to the active power of the motor controller and the motor and the rotating speed of the motor.

The method comprises the following steps of calculating the torque of the motor, and obtaining the actual output torque of the main drive motor by adopting the following formula:

T_mech＝P_intη/ω

in the formula, P_intRepresenting the calculated motor controller output power; η motor controller and motor system efficiency; ω represents the motor speed.

As shown in fig. 5, in one embodiment, there is provided a torque monitoring device of a motor for a vehicle, which may include:

the motor rotating speed monitoring unit is used for monitoring the rotating speed of the motor and judging whether the rotating speed of the motor is smaller than a preset rotating speed threshold value or not;

a first torque calculation unit for calculating an estimated torque of the motor according to a current signal of the motor and a rotor position signal based on a current model of the motor if a rotation speed of the motor is less than a rotation speed threshold;

the second torque calculation unit is used for calculating the estimated torque of the motor according to a PWM signal generated by motor vector control, a direct-current bus voltage signal input by a motor controller and a driving phase current signal of the motor based on a power model of the motor if the rotating speed of the motor is not less than a rotating speed threshold;

a torque safety judgment unit for calculating a difference between the estimated torque and a requested torque of the motor, judging whether the difference is greater than a preset difference threshold,

if the torque is larger than the preset torque, outputting a torque violation signal of the motor, and triggering corresponding safety measures;

and if not, outputting a normal torque signal of the main control motor.

In one embodiment, an automobile is provided, the automobile comprising a processor, a memory, and a computer program stored on the memory and executable on the processor, the processor implementing when executing the computer program: monitoring the rotating speed of the motor, judging whether the rotating speed of the motor is smaller than a preset rotating speed threshold value or not, and if so, calculating the estimated torque of the motor according to a current signal and a rotor position signal of the motor based on a current model of the motor; if not, calculating the estimated torque of the motor according to a PWM signal generated by motor vector control, a direct current bus voltage signal input by a motor controller and a driving phase current signal of the motor based on a power model of the motor; calculating a difference value between the estimated torque and the requested torque of the motor, judging whether the difference value is larger than a preset difference value threshold value, if so, outputting a torque violation signal of the motor, and triggering a corresponding safety measure; and if not, outputting a normal torque signal of the main control motor.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and can include the processes of the embodiments of the methods described above when the computer program is executed. The storage medium may be a non-volatile storage medium such as a magnetic disk, an optical disk, a Read-Only Memory (ROM), or a Random Access Memory (RAM).

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.