1. A method of controlling torque of an electric machine, the method comprising:

acquiring a first torque proportion of a left motor and a right motor of a vehicle under a driving working condition and a second torque proportion of the left motor and the right motor under a braking working condition;

when the current slip rate of the wheel meets a first preset condition, acquiring torque adjustment values of the left motor and the right motor; the current slip rate comprises a left side slip rate and a right side slip rate;

under the driving working condition, when the pre-acquired actual yaw rate and the right-side slip rate of the vehicle meet a second preset condition, adjusting the torque limit value of the right-side motor through the torque adjustment value to obtain a first adjustment result, and adjusting the torque limit value of the left-side motor through the first adjustment result and the first torque proportion;

under the braking working condition, when the actual yaw rate and the left side slip rate meet a third preset condition, the torque limit value of the left side motor is adjusted through the torque adjustment value to obtain a second adjustment result, and the torque limit value of the right side motor is adjusted through the second adjustment result and the second torque proportion.

2. The method of claim 1, wherein obtaining a first torque ratio of a left side motor and a right side motor of the vehicle under a driving condition and a second torque ratio of the left side motor and the right side motor under a braking condition comprises:

acquiring a current vehicle speed and a current steering wheel angle;

based on a preset vehicle speed grade, performing vehicle speed grade division on the current vehicle speed to obtain a vehicle speed grade corresponding to the current vehicle speed;

based on a preset steering wheel corner grade, carrying out steering wheel corner grade division on the current steering wheel corner to obtain a steering wheel corner grade corresponding to the current steering wheel corner;

and acquiring a first torque proportion of a left motor and a right motor of the vehicle under a driving working condition and a second torque proportion of the left motor and the right motor of the vehicle under a braking working condition under the vehicle speed grade corresponding to the current vehicle speed and the steering wheel angle grade corresponding to the current steering wheel angle.

3. The method of claim 1, wherein obtaining the torque adjustment values for the left side motor and the right side motor when the current slip ratio of the wheel meets a first preset condition comprises:

when the current slip rate of the wheels is smaller than the preset slip rate, calculating the difference between the preset yaw rate and the obtained actual yaw rate to obtain a difference value;

and calculating the difference value based on a preset algorithm to obtain the torque adjustment values of the left motor and the right motor.

4. The method according to claim 1, wherein in the driving condition, when the pre-acquired actual yaw rate and the right slip ratio of the vehicle meet a second preset condition, the torque limit value of the right motor is adjusted through the torque adjustment value to obtain a first adjustment result, and the torque limit value of the left motor is adjusted through the first adjustment result and the first torque proportion, and the method comprises the following steps:

under the driving working condition, when the pre-acquired actual yaw rate of the vehicle is smaller than a preset yaw rate and the right-side slip rate is smaller than a first preset slip rate, adjusting the torque limit value of the right-side motor through the torque adjustment value to obtain a first adjustment result, and adjusting the torque limit value of the left-side motor through the first adjustment result and the first torque proportion.

5. The method according to claim 1, wherein in the braking condition, when the actual yaw rate and the left-side slip rate meet a third preset condition, the torque limit value of the left-side motor is adjusted through the torque adjustment value to obtain a second adjustment result, and the torque limit value of the right-side motor is adjusted through the second adjustment result and the second torque proportion, and the method comprises the following steps:

under the braking condition, when the actual yaw rate is smaller than the preset yaw rate and the left side slip rate is smaller than a second preset slip rate, the torque limit value of the left side motor is adjusted through the torque adjustment value to obtain a second adjustment result, and the torque limit value of the right side motor is adjusted through the second adjustment result and the second torque proportion.

6. A motor torque control system, the system comprising:

the system comprises a first acquisition unit, a second acquisition unit and a control unit, wherein the first acquisition unit is used for acquiring a first torque proportion of a left motor and a right motor of a vehicle under a driving working condition and a second torque proportion of the left motor and the right motor under a braking working condition;

the second acquisition unit is used for acquiring torque adjustment values of the left motor and the right motor when the current slip rate of the wheel meets a first preset condition; the current slip rate comprises a left side slip rate and a right side slip rate;

the first adjusting unit is used for adjusting the torque limit value of the right side motor through the torque adjusting value to obtain a first adjusting result when the actual yaw rate and the right side slip rate of the vehicle, which are acquired in advance, meet a second preset condition under the driving working condition, and adjusting the torque limit value of the left side motor through the first adjusting result and the first torque proportion;

and the second adjusting unit is used for adjusting the torque limit value of the left motor through the torque adjusting value to obtain a second adjusting result and adjusting the torque limit value of the right motor through the second adjusting result and the second torque proportion when the actual yaw rate and the left slip rate meet a third preset condition under the braking working condition.

7. The system of claim 6, wherein the first obtaining unit comprises:

the first acquisition module is used for acquiring the current vehicle speed and the current steering wheel angle;

the first dividing module is used for dividing the current vehicle speed into vehicle speed grades based on a preset vehicle speed grade to obtain a vehicle speed grade corresponding to the current vehicle speed;

the second division module is used for carrying out steering wheel corner grade division on the current steering wheel corner based on a preset steering wheel corner grade to obtain a steering wheel corner grade corresponding to the current steering wheel corner;

the second obtaining module is used for obtaining a first torque proportion of a left side motor and a right side motor of the vehicle under a driving working condition and a second torque proportion of the left side motor and the right side motor of the vehicle under a braking working condition under the vehicle speed grade corresponding to the current vehicle speed and the steering wheel angle grade corresponding to the current steering wheel angle.

8. The system of claim 6, wherein the second obtaining unit comprises:

the first calculation module is used for calculating the difference between the preset yaw velocity and the obtained actual yaw velocity to obtain a difference value when the current slip rate of the wheels is smaller than the preset slip rate;

and the second calculation module is used for calculating the difference value based on a preset algorithm to obtain the torque adjustment values of the left motor and the right motor.

9. The system according to claim 6, wherein the first adjusting unit is specifically configured to:

under the driving working condition, when the pre-acquired actual yaw rate of the vehicle is smaller than a preset yaw rate and the right-side slip rate is smaller than a first preset slip rate, adjusting the torque limit value of the right-side motor through the torque adjustment value to obtain a first adjustment result, and adjusting the torque limit value of the left-side motor through the first adjustment result and the first torque proportion.

10. The system according to claim 6, wherein the second adjusting unit is specifically configured to:

under the braking condition, when the actual yaw rate is smaller than the preset yaw rate and the left side slip rate is smaller than a second preset slip rate, the torque limit value of the left side motor is adjusted through the torque adjustment value to obtain a second adjustment result, and the torque limit value of the right side motor is adjusted through the second adjustment result and the second torque proportion.

Background

When the new energy automobile is in an electric drive mode, the power battery provides working current for the driving motor so that the driving motor outputs corresponding torque.

The two distributed driving system motors of the new energy automobile rear drive are not unique and are influenced by the limit power of battery charging and discharging, and the total torque of the two motors is limited in the driving process and the braking process, so that the two motors cannot fully utilize the charging and discharging power of the power battery, and the driving performance and the economic performance of the new energy automobile are reduced.

Therefore, the existing new energy automobile has low drivability and economic performance during driving and braking.

Disclosure of Invention

In view of this, the application discloses a motor torque control method and system, and aims to improve the drivability and the economic performance of a new energy vehicle.

In order to achieve the purpose, the technical scheme is as follows:

the application discloses in a first aspect a method for controlling motor torque, the method comprising:

acquiring a first torque proportion of a left motor and a right motor of a vehicle under a driving working condition and a second torque proportion of the left motor and the right motor under a braking working condition;

when the current slip rate of the wheel meets a first preset condition, acquiring torque adjustment values of the left motor and the right motor; the current slip rate comprises a left side slip rate and a right side slip rate;

under the driving working condition, when the pre-acquired actual yaw rate and the right-side slip rate of the vehicle meet a second preset condition, adjusting the torque limit value of the right-side motor through the torque adjustment value to obtain a first adjustment result, and adjusting the torque limit value of the left-side motor through the first adjustment result and the first torque proportion;

under the braking working condition, when the actual yaw rate and the left side slip rate meet a third preset condition, the torque limit value of the left side motor is adjusted through the torque adjustment value to obtain a second adjustment result, and the torque limit value of the right side motor is adjusted through the second adjustment result and the second torque proportion.

Preferably, the obtaining a first torque ratio of the left motor and the right motor of the vehicle under a driving condition and a second torque ratio of the left motor and the right motor under a braking condition includes:

acquiring a current vehicle speed and a current steering wheel angle;

based on a preset vehicle speed grade, performing vehicle speed grade division on the current vehicle speed to obtain a vehicle speed grade corresponding to the current vehicle speed;

based on a preset steering wheel corner grade, carrying out steering wheel corner grade division on the current steering wheel corner to obtain a steering wheel corner grade corresponding to the current steering wheel corner;

and acquiring a first torque proportion of a left motor and a right motor of the vehicle under a driving working condition and a second torque proportion of the left motor and the right motor of the vehicle under a braking working condition under the vehicle speed grade corresponding to the current vehicle speed and the steering wheel angle grade corresponding to the current steering wheel angle.

Preferably, when the current slip ratio of the wheel meets a first preset condition, acquiring the torque adjustment values of the left motor and the right motor includes:

when the current slip rate of the wheels is smaller than the preset slip rate, calculating the difference between the preset yaw rate and the obtained actual yaw rate to obtain a difference value;

and calculating the difference value based on a preset algorithm to obtain the torque adjustment values of the left motor and the right motor.

Preferably, under the driving condition, when the pre-acquired actual yaw rate of the vehicle and the right-side slip rate meet a second preset condition, adjusting the torque limit value of the right-side motor by the torque adjustment value to obtain a first adjustment result, and adjusting the torque limit value of the left-side motor by the first adjustment result and the first torque ratio, includes:

under the driving working condition, when the pre-acquired actual yaw rate of the vehicle is smaller than a preset yaw rate and the right-side slip rate is smaller than a first preset slip rate, adjusting the torque limit value of the right-side motor through the torque adjustment value to obtain a first adjustment result, and adjusting the torque limit value of the left-side motor through the first adjustment result and the first torque proportion.

Preferably, under the braking condition, when the actual yaw rate and the left-side slip rate meet a third preset condition, the adjusting the torque limit value of the left-side motor by the torque adjustment value to obtain a second adjustment result, and adjusting the torque limit value of the right-side motor by the second adjustment result and the second torque ratio includes:

under the braking condition, when the actual yaw rate is smaller than the preset yaw rate and the left side slip rate is smaller than a second preset slip rate, the torque limit value of the left side motor is adjusted through the torque adjustment value to obtain a second adjustment result, and the torque limit value of the right side motor is adjusted through the second adjustment result and the second torque proportion.

A second aspect of the present application discloses a motor torque control system, the system comprising:

the system comprises a first acquisition unit, a second acquisition unit and a control unit, wherein the first acquisition unit is used for acquiring a first torque proportion of a left motor and a right motor of a vehicle under a driving working condition and a second torque proportion of the left motor and the right motor under a braking working condition;

the second acquisition unit is used for acquiring torque adjustment values of the left motor and the right motor when the current slip rate of the wheel meets a first preset condition; the current slip rate comprises a left side slip rate and a right side slip rate;

the first adjusting unit is used for adjusting the torque limit value of the right side motor through the torque adjusting value to obtain a first adjusting result when the actual yaw rate and the right side slip rate of the vehicle, which are acquired in advance, meet a second preset condition under the driving working condition, and adjusting the torque limit value of the left side motor through the first adjusting result and the first torque proportion;

and the second adjusting unit is used for adjusting the torque limit value of the left motor through the torque adjusting value to obtain a second adjusting result and adjusting the torque limit value of the right motor through the second adjusting result and the second torque proportion when the actual yaw rate and the left slip rate meet a third preset condition under the braking working condition.

Preferably, the first obtaining unit includes:

the first acquisition module is used for acquiring the current vehicle speed and the current steering wheel angle;

the first dividing module is used for dividing the current vehicle speed into vehicle speed grades based on a preset vehicle speed grade to obtain a vehicle speed grade corresponding to the current vehicle speed;

the second division module is used for carrying out steering wheel corner grade division on the current steering wheel corner based on a preset steering wheel corner grade to obtain a steering wheel corner grade corresponding to the current steering wheel corner;

the second obtaining module is used for obtaining a first torque proportion of a left side motor and a right side motor of the vehicle under a driving working condition and a second torque proportion of the left side motor and the right side motor of the vehicle under a braking working condition under the vehicle speed grade corresponding to the current vehicle speed and the steering wheel angle grade corresponding to the current steering wheel angle.

Preferably, the second obtaining unit includes:

the first calculation module is used for calculating the difference between the preset yaw velocity and the obtained actual yaw velocity to obtain a difference value when the current slip rate of the wheels is smaller than the preset slip rate;

and the second calculation module is used for calculating the difference value based on a preset algorithm to obtain the torque adjustment values of the left motor and the right motor.

Preferably, the first adjusting unit is specifically configured to:

under the driving working condition, when the pre-acquired actual yaw rate of the vehicle is smaller than a preset yaw rate and the right-side slip rate is smaller than a first preset slip rate, adjusting the torque limit value of the right-side motor through the torque adjustment value to obtain a first adjustment result, and adjusting the torque limit value of the left-side motor through the first adjustment result and the first torque proportion.

Preferably, the second adjusting unit is specifically configured to:

under the braking condition, when the actual yaw rate is smaller than the preset yaw rate and the left side slip rate is smaller than a second preset slip rate, the torque limit value of the left side motor is adjusted through the torque adjustment value to obtain a second adjustment result, and the torque limit value of the right side motor is adjusted through the second adjustment result and the second torque proportion.

According to the technical scheme, a first torque proportion under a driving working condition and a second torque proportion under a braking working condition are obtained, when the slip rate of the obtained wheels accords with a first preset condition, a torque adjusting value of a left side motor and a torque adjusting value of a right side motor are obtained, when the obtained actual yaw rate and the obtained right side slip rate accord with a second preset condition under the driving working condition, the torque limit value of the right side motor is adjusted through the torque adjusting value to obtain a first adjusting result, the torque limit value of the left side motor is adjusted through the first adjusting result and the first torque proportion, when the actual yaw rate and the left side slip rate accord with a third preset condition under the braking working condition, the torque limit value of the left side motor is adjusted through the torque adjusting value to obtain a second adjusting result, and based on the second adjusting result and the second torque proportion, the torque limit of the right side motor is adjusted. Through the scheme, under two working conditions of driving and braking, the limit value adjustment of the motor torque is realized, the full utilization of the charge and discharge power of the battery is ensured, and the driving performance and the economical efficiency of the vehicle are improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic flow chart of a method for controlling torque of a motor according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram illustrating vehicle speed grades corresponding to a current vehicle speed obtained by vehicle speed grade classification of the current vehicle speed disclosed in the embodiment of the present application;

fig. 3 is a schematic diagram of performing steering wheel angle grade division on a current steering wheel angle to obtain a steering wheel angle grade corresponding to the current steering wheel angle, which is disclosed in the embodiment of the present application;

FIG. 4 is a schematic diagram illustrating obtaining a first torque ratio of a left side motor and a right side motor of a vehicle under a driving condition according to an embodiment of the disclosure;

FIG. 5 is a schematic diagram illustrating a second torque ratio of the left side motor and the right side motor of the vehicle under braking conditions;

FIG. 6 is a schematic diagram illustrating a determination that a current side slip ratio is out of limit in an embodiment of the present application;

FIG. 7 is a schematic diagram illustrating obtaining torque adjustment values of a left side motor and a right side motor according to an embodiment of the disclosure;

FIG. 8 is a schematic diagram illustrating a process for calculating torque limits of the left side motor and the right side motor under driving conditions according to an embodiment of the disclosure;

FIG. 9 is a schematic illustration of a process for calculating torque limits for the left side motor and the right side motor during a braking condition as disclosed in an embodiment of the present application;

FIG. 10 is a schematic flow chart illustrating a process for obtaining a first torque ratio under a driving condition and a second torque ratio under a braking condition according to an embodiment of the present disclosure;

FIG. 11 is a schematic diagram illustrating a process for obtaining torque adjustment values of a left side motor and a right side motor according to an embodiment of the present disclosure;

fig. 12 is a schematic structural diagram of a motor torque control system according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

As known in the background art, the existing new energy automobile has low driving performance and economic performance in the driving process and the braking process.

In order to solve the problem, the embodiment of the application discloses a motor torque control method and a motor torque control system, which realize the adjustment of the limit value of the motor torque under two working conditions of driving and braking, ensure the full utilization of the charge and discharge power of a battery and improve the driving performance and the economical efficiency of a vehicle. The specific implementation is illustrated by the following examples.

Referring to fig. 1, a schematic flow chart of a motor torque control method disclosed in an embodiment of the present application is shown, where the motor torque control method mainly includes the following steps:

s101: the method comprises the steps of obtaining a first torque proportion of a left motor and a right motor of a vehicle under a driving working condition and a second torque proportion of the left motor and the right motor under a braking working condition.

In S101, a current vehicle speed and a current steering wheel angle are graded, and then under different grades, a first torque proportion of a left motor and a right motor of a vehicle under a driving working condition and a second torque proportion of the left motor and the right motor under a braking working condition are obtained.

The current vehicle speed is obtained through a vehicle speed sensor, and the current steering wheel angle is obtained through a steering wheel angle sensor.

The first torque proportion and the second torque proportion are obtained by looking up values in a MAP (MAP) according to a vehicle speed level and a steering wheel angle level.

The process of specifically obtaining the first torque proportion of the left motor and the right motor of the vehicle under the driving working condition and the second torque proportion of the left motor and the right motor under the braking working condition is as follows:

firstly, acquiring a current vehicle speed and a current steering wheel angle; secondly, carrying out vehicle speed grade division on the current vehicle speed based on a preset vehicle speed grade to obtain a vehicle speed grade corresponding to the current vehicle speed; then, based on a preset steering wheel corner grade, carrying out steering wheel corner grade division on the current steering wheel corner to obtain a steering wheel corner grade corresponding to the current steering wheel corner; and finally, acquiring a first torque proportion of the left motor and the right motor of the vehicle under a driving working condition and a second torque proportion of the left motor and the right motor under a braking working condition under a vehicle speed grade corresponding to the current vehicle speed and a steering wheel angle grade corresponding to the current steering wheel angle.

And performing vehicle speed grade division on the current vehicle speed to obtain a vehicle speed grade corresponding to the current vehicle speed, which can refer to fig. 2.

In fig. 2, vVeh is the current vehicle speed, vVeh1, vVeh2, vVeh3, vVeh4, and vVeh5 are vehicle speed class division target amounts, vDiffVeh is a vehicle speed class division frequent jump prevention difference value, EN: stVeh _ mp is a vehicle speed class, EN: stVeh _ mp is 0, EN: stVeh _ mp is 1, EN: stVeh _ mp is 2, EN: stVeh _ mp is 3, EN: stVeh _ mp is 4, and EN: stVeh _ mp is 5 for indicating 5 different vehicle speed classes.

Dividing the vehicle speed into different vehicle speed grades according to the vehicle speed, and dispersing the continuous variable of the vehicle speed into a state corresponding to the vehicle speed grade.

The current steering wheel angle is classified into steering wheel angle grades to obtain the steering wheel angle grade corresponding to the current steering wheel angle, which can refer to fig. 3.

In fig. 3, stStrWh1_ mp is a steering wheel angle rank, agstrwh is a current steering wheel angle, agstrwh 1, agstrwh 2, agstrwh 3, agstrwh 4, and agStrWhl5 are steering wheel angle rank division reference amounts, agstepdiffveh _ C is a steering wheel angle rank division frequent jump prevention difference value, X is an operation sign, En: stStrWhl _ mp ═ 1, En: stStrWhl _ mp ═ 2, En: stStrWhl _ mp ═ 3, En: stStrWhl _ mp ═ 4, and En: stStrWhl _ mp ═ 5 are used to indicate 5 different steering wheel angle ranks.

And dividing the steering wheel into different steering wheel angle grades according to the steering wheel angle, and dispersing the continuous variable of the steering wheel angle into a state corresponding to the steering wheel angle grade.

The first torque ratio of the left side motor and the right side motor of the vehicle under the driving condition is obtained, and the processing process refers to fig. 4.

In fig. 4, SpdEst _ vVeh is the current vehicle speed, Rx _ agStrWhl is the current steering wheel angle, rststrwhdrv is the first torque ratio of the left and right motors in the driving condition, SpdEst _ vVeh is input to the VehVelst module for processing, Rx _ agStrWhl is input to the StrWhlSt module for processing after being preprocessed, and SpdEst _ vVeh and Rx _ agStrWhl after being preprocessed are output to the MAP strwhldrv via the rststrwhldrv _ output.

And acquiring a second torque ratio of the left motor and the right motor under the braking condition of the vehicle, and referring to fig. 5.

In fig. 5, SpdEst _ vVeh is the current vehicle speed, Rx _ agstrwl is the current steering wheel angle, rstrwstrlgn is the second torque ratio of the left and right motors in the braking condition, SpdEst _ vVeh is input to the VehVelst module for processing, Rx _ agstrwl is pre-processed and input to the StrWhlSt module for processing, and SpdEst _ vVeh and Rx _ agstrwl after processing are output to the rstrwstrlgn via the strrwign _ MAP.

S102: when the current slip rate of the wheel meets a first preset condition, acquiring torque adjustment values of a left motor and a right motor; the current slip rate includes a left-side slip rate and a right-side slip rate.

In S102, when the pre-acquired current slip rate of the wheels is smaller than the preset slip rate, it is determined that the current slip rate of the wheels meets a first preset condition (i.e., the current slip rate exceeds a limit), and torque adjustment values of the left side motor and the right side motor are obtained by calculating the preset yaw rate and the pre-acquired actual yaw rate.

The current slip rate is limited by the effect of the actual acceleration of the vehicle.

The determination of the preset slip ratio is set by a technician according to actual conditions, and the invention is not particularly limited.

Specifically, when the current slip ratio of the wheel meets a first preset condition, the process of obtaining the torque adjustment values of the left motor and the right motor is as follows:

first, when the slip rate of the wheels is smaller than the preset slip rate, the difference between the preset yaw rate and the obtained actual yaw rate is calculated to obtain a difference (yaw rate deviation), and then, the difference is calculated based on a preset algorithm, such as a (Proportion integration Differential, PID) algorithm, to obtain a torque adjustment value of the left side motor and a torque adjustment value of the right side motor.

The determination of the preset yaw rate is set by a technician according to an actual situation, and the present application is not particularly limited.

For the determination that the current side slip ratio exceeds the limit range, refer to fig. 6.

In fig. 6, SlpRtCal _ rRL is a left-side slip rate, SpdEst _ aVeh is a current vehicle acceleration, SlpRtAdjDrvRL _ CUR is a slip rate required adjustment limit value for a left rear wheel drive condition, SlpRtOffSetRL _ C is a left-side slip rate release adjustment limit value difference value, and ≧ and ≦ are arithmetic symbols, SlpRtCal _ rRR is a right-side slip rate, and SlpRtOffSetRR _ C is a right-side slip rate release adjustment limit value difference value.

In fig. 6, it is determined whether torque adjustment is required for the current vehicle wheel by comparing the slip ratio (left-side slip ratio and right-side slip ratio) with the set slip ratio adjustment required limit for the left-rear wheel drive condition.

The torque adjustment values of the left motor and the right motor are obtained, and reference is made to fig. 7.

In fig. 7, yawrattedes is the desired yaw rate, and yawratteact is the current actual yaw rate.

Fig. 7 is a diagram showing PID calculations based on a deviation between a desired yaw rate and a current actual yaw rate, resulting in torque adjustment values of the left-side motor and the right-side motor.

S103: under the driving working condition, when the pre-acquired actual yaw rate and the right-side slip rate of the vehicle meet a second preset condition, the torque limit value of the right-side motor is adjusted through the torque adjustment value to obtain a first adjustment result, and the torque limit value of the left-side motor is adjusted through the first adjustment result and the first torque proportion.

In S103, if the vehicle is in the driving condition, when the actual yaw rate of the vehicle is less than the preset yaw rate and the right-side slip rate is less than the first preset slip rate, it is determined that the actual yaw rate and the right-side slip rate meet a second preset condition.

The determination of the first preset slip ratio is set by a technician according to an actual situation, and the present invention is not particularly limited.

Under the driving working condition, the torque output of the right motor is preferentially ensured under the condition that the expected yaw rate is larger than the actual yaw rate and the right slip rate does not exceed the torque limit value, the torque limit value of the right motor is preferentially adjusted, and the torque limit value is readjusted by the left motor according to the adjusted result of the right motor.

And adjusting the torque limit value of the motors on the left side and the right side according to the charge and discharge power limit requirements of the battery under two different conditions of a driving condition and a braking condition.

The scheme can realize the limit value adjustment of the motor torque only through adjusting software, ensures the full utilization of the charge and discharge power of the battery, also ensures the drivability and the economy of the whole vehicle, and simultaneously avoids the overcharge or the overdischarge of the battery by taking the charge and discharge limit value of the battery as the limit.

Specifically, under the driving condition, when the actual yaw rate and the right-side slip rate of the vehicle which are obtained in advance meet a second preset condition, the torque of the right-side motor is adjusted through a torque adjustment value to obtain a first adjustment result, and the process of adjusting the torque limit value of the left-side motor through the first adjustment result and the first torque proportion is as follows:

under the driving working condition, when the actual yaw velocity of the vehicle is smaller than the preset yaw velocity and the right-side slip rate is smaller than the first preset slip rate, the torque limit value of the right-side motor is adjusted through the torque adjustment value to obtain a first adjustment result, and the torque limit value of the left-side motor is adjusted through the first adjustment result and the first torque proportion.

For convenience of understanding, the process of adjusting the torque of the right-side motor by the torque adjustment value to obtain a first adjustment result, and adjusting the torque of the left-side motor by the first adjustment result and the first torque ratio is described as an example here:

for example, the actual yaw rate is 10 °/s, the preset yaw rate is 15 °/s, the right-side slip rate is 20%, the first preset slip rate is 70%, the torque adjustment value is 40% calculated based on the preset PID algorithm, the first torque proportion is 100%, the actual yaw rate is less than the preset yaw rate, and the right-side slip rate is less than the first preset slip rate, the torque limit value of the right-side motor is adjusted by the torque adjustment value of 40%, and the left-side motor torque limit value is adjusted by the allocated torque proportion of 60% since the first torque proportion is 100%.

The process of calculating the torque limits for the left and right motors during driving conditions may be referred to in FIG. 8.

In fig. 8, pwrbettdischrlmt is the power battery discharge power limit, RLMTSpdAct is the left rear wheel motor speed, and RRMTSpdAct is the right rear wheel motor speed.

Under the driving working condition, the torque output of the right motor is preferentially ensured under the condition that the expected yaw rate is larger than the actual yaw rate and the right slip rate does not exceed the torque limit value, the torque limit value of the right motor is preferentially adjusted, and the torque limit value is readjusted by the left motor according to the adjusted result of the right motor.

S104: under the braking working condition, when the actual yaw rate and the left-side slip rate meet a third preset condition, the torque limit value of the left-side motor is adjusted through the torque adjustment value to obtain a second adjustment result, and the torque limit value of the right-side motor is adjusted through the second adjustment result and the second torque proportion.

In step S104, if the vehicle is in the braking condition, when the obtained actual yaw rate of the vehicle is less than the preset yaw rate and the left-side slip rate is less than the second preset slip rate, it is determined that the actual yaw rate and the left-side slip rate meet a third preset condition.

The determination of the second preset slip ratio is set by a technician according to an actual situation, and the application is not particularly limited.

Under the braking condition, when the expected yaw rate is larger than the current actual yaw rate and the slip rate of the left side does not exceed the torque limit value, the torque output of the left side motor is limited, the braking force (negative value) of the left side motor is increased, and the torque limit value is readjusted by the right side motor according to the adjusted result of the left side motor.

Specifically under the braking condition, when the actual yaw rate and the left-side slip rate meet a third preset condition, the torque limit value of the left-side motor is adjusted through the torque adjustment value to obtain a second adjustment result, and the process of adjusting the torque limit value of the right-side motor is as follows through the second adjustment result and the second torque proportion:

under the braking condition, when the obtained actual yaw rate is smaller than the preset yaw rate and the left-side slip rate is smaller than a second preset slip rate, the torque limit value of the left-side motor is adjusted through the torque adjustment value to obtain a second adjustment result, and the torque limit value of the right-side motor is adjusted through the second adjustment result and the second torque proportion.

For example, it is convenient to understand a process of adjusting the torque limit value of the left motor by the torque adjustment value to obtain a second adjustment result, and adjusting the torque limit value of the right motor by the second adjustment result and the second torque ratio, where the following example is illustrated:

for example, the actual yaw rate is 13 °/s, the preset yaw rate is 16 °/s, the left-side slip rate is 30%, the second preset slip rate is 50%, the torque adjustment value is 50% based on the preset PID algorithm, the second torque proportion is 100%, the actual yaw rate is smaller than the preset yaw rate, and the right-side slip rate is smaller than the second preset slip rate, the torque limit value of the right-side motor is adjusted by the torque adjustment value of 50%, and the torque limit value of the right-side motor is adjusted by allocating the torque proportion of 50% since the second torque proportion is 100%.

In the embodiment of the application, under two working conditions of driving and braking, the limit value adjustment of the motor torque is realized, the full utilization of the charge and discharge power of the battery is ensured, and the driving performance and the economical efficiency of the vehicle are improved.

The process of calculating the torque limits for the left and right electric machines during braking conditions may be referred to in FIG. 9.

In fig. 9, RLMTSpdAct is the left rear wheel motor speed, rrmtsspdact is the right rear wheel motor speed, and pwrbettchrlmt is the power battery charging power limit.

Under the braking condition, when the expected yaw rate is larger than the current actual yaw rate and the slip rate of the left side does not exceed the torque limit value, the torque output of the left side motor is limited, the braking force (negative value) of the left side motor is increased, and the torque limit value is readjusted by the right side motor according to the adjusted result of the left side motor.

The scheme can realize the limit value adjustment of the motor torque only through adjusting software, ensures the full utilization of the charge and discharge power of the battery, also ensures the drivability and the economy of the whole vehicle, and simultaneously avoids the overcharge or the overdischarge of the battery by taking the charge and discharge limit value of the battery as the limit.

In the embodiment of the invention, under the driving working condition, when the actual yaw rate and the right side slip rate accord with the second preset condition, the torque limit value of the right side motor is adjusted through the torque adjusting value, the torque limit value of the left side motor is adjusted through the adjusted result and the first torque proportion, under the braking working condition, when the actual yaw rate and the left side slip rate accord with the third preset condition, the torque limit value of the left side motor is adjusted through the torque adjusting value, and the torque limit value of the right side motor is adjusted through the adjusted result and the second torque proportion. Through the scheme, under two working conditions of driving and braking, the torque limit value of the motor is adjusted, the full utilization of the charge and discharge power of the battery is ensured, and the driving performance and the economical efficiency of the vehicle are improved.

Referring to fig. 10, the process involved in obtaining the first torque proportion under the driving condition and the second torque proportion under the braking condition in S101 above mainly includes the following steps:

s1001: and acquiring the current vehicle speed and the current steering wheel angle.

In S1001, a current vehicle speed is acquired by a vehicle speed sensor, and a current steering wheel angle is acquired by a steering wheel angle sensor.

S1002: and carrying out vehicle speed grade division on the current vehicle speed based on a preset vehicle speed grade to obtain a vehicle speed grade corresponding to the current vehicle speed.

The vehicle speed is divided into different vehicle speed grades according to the vehicle speed, and the continuous variable of the vehicle speed is dispersed into a state corresponding to the vehicle speed grade.

S1003: and based on the preset steering wheel corner grade, carrying out steering wheel corner grade division on the current steering wheel corner to obtain the steering wheel corner grade corresponding to the current steering wheel corner.

The steering wheel angle is divided into different steering wheel angle grades according to the steering wheel angle, and the continuous variable of the steering wheel angle is dispersed into a state corresponding to the steering wheel angle grades.

S1004: under the conditions of a vehicle speed grade corresponding to the current vehicle speed and a steering wheel angle grade corresponding to the current steering wheel angle, acquiring a first torque proportion of a left motor and a right motor of a vehicle under a driving working condition and a second torque proportion of the left motor and the right motor of the vehicle under a braking working condition.

And the first torque proportion and the second torque proportion are obtained by checking MAP values according to the vehicle speed grade and the steering wheel angle grade.

In the embodiment of the application, under the vehicle speed grade corresponding to the current vehicle speed and the steering wheel angle grade corresponding to the current steering wheel angle, the purpose of obtaining the first torque proportion of the left motor and the right motor under the driving working condition and the second torque proportion of the left motor and the right motor under the braking working condition is achieved.

Referring to fig. 11, a process of obtaining torque adjustment values of the left motor and the right motor when the pre-obtained slip ratio of the wheel meets the first preset condition in S102 mainly includes the following steps:

s1101: and when the current slip rate of the wheels is smaller than the preset slip rate, calculating the difference between the preset yaw rate and the obtained actual yaw rate to obtain a difference value.

In S1101, a difference calculation is performed between the preset yaw rate and the acquired actual yaw rate, and a difference value (yaw rate deviation) is obtained.

S1102: and calculating the difference value based on a preset algorithm to obtain the torque adjustment values of the left motor and the right motor.

In S1102, the preset algorithm may be a PID algorithm or the like.

In the embodiment of the application, when the current slip rate of the wheels is smaller than the preset slip rate, the difference between the preset yaw rate and the obtained actual yaw rate is calculated to obtain a difference value, and the difference value is calculated based on a preset algorithm to achieve the purpose of obtaining the torque adjustment values of the left motor and the right motor.

Based on the motor torque control method disclosed in fig. 1 in the foregoing embodiment, an embodiment of the present application further discloses a motor torque control system correspondingly, and as shown in fig. 12, the motor torque control system mainly includes a first obtaining unit 1201, a second obtaining unit 1202, a first adjusting unit 1203, and a second adjusting unit 1204.

The first obtaining unit 1201 is configured to obtain a first torque ratio of the left motor and the right motor of the vehicle in a driving condition and a second torque ratio of the left motor and the right motor in a braking condition.

A second obtaining unit 1202, configured to obtain torque adjustment values of the left motor and the right motor when the current slip ratio of the wheel meets a first preset condition; the current slip rate includes a left-side slip rate and a right-side slip rate.

The first adjusting unit 1203 is configured to, under the driving condition, adjust the torque limit value of the right-side motor according to the torque adjustment value when the pre-obtained actual yaw rate and the right-side slip rate meet a second preset condition, to obtain a first adjustment result, and adjust the torque limit value of the left-side motor according to the first adjustment result and the first torque ratio.

And a second adjusting unit 1204, configured to, under the braking condition, adjust the torque limit value of the left motor according to the torque adjustment value when the actual yaw rate and the left slip rate meet a third preset condition, to obtain a second adjustment result, and adjust the torque limit value of the right motor according to the second adjustment result and the second torque ratio.

Further, the first obtaining unit 1201 includes a first obtaining module, a first dividing module, a second dividing module, and a second obtaining module.

The first acquisition module is used for acquiring the current vehicle speed and the current steering wheel angle.

The first division module is used for carrying out vehicle speed grade division on the current vehicle speed based on a preset vehicle speed grade to obtain a vehicle speed grade corresponding to the current vehicle speed.

And the second division module is used for carrying out steering wheel corner grade division on the current steering wheel corner based on the preset steering wheel corner grade to obtain the steering wheel corner grade corresponding to the current steering wheel corner.

The second acquisition module is used for acquiring a first torque proportion of a left motor and a right motor of the vehicle under a driving working condition and a second torque proportion of the left motor and the right motor of the vehicle under a braking working condition under the conditions of a vehicle speed grade corresponding to the current vehicle speed and a steering wheel angle grade corresponding to the current steering wheel angle.

Further, the second obtaining unit 1202 includes a first calculating module and a second calculating module.

And the first calculation module is used for calculating the difference between the preset yaw rate and the obtained actual yaw rate to obtain a difference value when the current slip rate of the wheels is smaller than the preset slip rate.

And the second calculation module is used for calculating the difference value based on a preset algorithm to obtain the torque adjustment values of the left motor and the right motor.

Further, the first adjusting unit 1203 is specifically configured to, under the driving condition, when the pre-obtained actual yaw rate of the vehicle is less than the preset yaw rate and the right-side slip rate is less than the first preset slip rate, adjust the torque limit value of the right-side motor by using the torque adjustment value to obtain a first adjustment result, and adjust the torque limit value of the left-side motor by using the first adjustment result and the first torque ratio.

Further, the second adjusting unit 1204 is specifically configured to, under the braking condition, adjust the torque limit value of the left-side motor by using the torque adjustment value when the actual yaw rate is less than the preset yaw rate and the left-side slip rate is less than the second preset slip rate, to obtain a second adjustment result, and adjust the torque limit value of the right-side motor by using the second adjustment result and the second torque ratio.

In the embodiment of the application, under two working conditions of driving and braking, the limit value adjustment of the motor torque is realized, the full utilization of the charge and discharge power of the battery is ensured, and the driving performance and the economical efficiency of the vehicle are improved.

While, for purposes of simplicity of explanation, the foregoing method embodiments have been described as a series of acts or combination of acts, it will be appreciated by those skilled in the art that the present application is not limited by the order of acts or acts described, as some steps may occur in other orders or concurrently with other steps in accordance with the application. Further, those skilled in the art should also appreciate that the embodiments described in the specification are preferred embodiments and that the acts and modules referred to are not necessarily required in this application.

It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. For the system-class embodiment, since it is basically similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The steps in the method of the embodiments of the present application may be sequentially adjusted, combined, and deleted according to actual needs.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The foregoing is only a preferred embodiment of the present application and it should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.