CN115675110A

CN115675110A - NVH motor control method for new energy automobile driving motor when torque passes through zero

Info

Publication number: CN115675110A
Application number: CN202210472720.2A
Authority: CN
Inventors: 史云峰; 刘雪锋; 范广丽; 王福全; 刘万喜; 景宇翔; 孙菁阳
Original assignee: FAW Bestune Car Co Ltd
Current assignee: FAW Bestune Car Co Ltd
Priority date: 2022-04-29
Filing date: 2022-04-29
Publication date: 2023-02-03

Abstract

According to the NVH motor control method for the new energy automobile when the torque of the driving motor is zero, the ABS wheel speed signal of the whole automobile is uploaded to the chassis CAN, the ABS wheel speed signal of the whole automobile is uploaded to the gateway through the chassis CAN, the ABS wheel speed signal of the whole automobile is uploaded to the EV-CAN through the gateway, when the torque of the motor is zero, the EV-CAN wheel speed signal is read, the rotating speed of the motor at the wheel speed is obtained through calculation and serves as the target rotating speed of the motor, the rotating speed of the motor is corrected by the rotating speed to control the rotating speed of the MCU controller, so that the linear speed difference between a driving wheel and a driven wheel in a meshing gear of the speed reducer is reduced to reduce collision noise, vehicle shaking and the tooth knocking sound of the speed reducer, and the NVH problem when the torque of the driving motor is zero crossing point is solved.

Description

NVH motor control method for new energy automobile driving motor when torque passes through zero

Technical Field

The invention relates to the technical field of new energy automobile NVH optimization, in particular to a control method of an NVH motor when the torque of a driving motor of a new energy automobile passes through zero.

Background

In a new energy automobile, a driving motor replaces an internal combustion engine, so that the 'masking effect' in a traditional fuel automobile disappears, but the noise of an electric driving system becomes a main noise source, and in some aspects, the noise problem of the driving motor of the new energy automobile is more prominent than that of the traditional internal combustion engine of the traditional fuel automobile. NVH is English abbreviation of noise, vibration and sound vibration roughness, NVH is a comprehensive problem for measuring automobile manufacturing quality, and gives most direct feeling to automobile users, and NVH of automobiles is one of the most concerned problems for large automobile manufacturing enterprises and part enterprises in the international automobile industry.

IN the switching process of the TIP-IN and TIP-OUT of the whole vehicle, when the torque of a driving motor crosses zero, the vehicle shakes and is accompanied by tooth knocking sound, the main reason is that gaps exist among meshing gears of a speed reducer, the pitch circle of the meshing gears of the speed reducer has certain linear speed difference at the meshing position of the gears of the speed reducer, so that the gears collide, the gear gaps objectively exist due to the manufacturing and assembling reasons of the gears of the speed reducer, the adjusting difficulty is large, the period is long, the cost is high, the effect is not good, the previous scheme adopts the mode of reducing the torque speed change of the motor, and certain effect is really realized, but the effect is not obvious.

Disclosure of Invention

The invention provides a control method of an NVH motor of a new energy automobile when the torque of a driving motor passes through zero aiming at the problems in the prior art.

The technical scheme adopted for realizing the invention is as follows: the NVH motor control method for the new energy automobile driving motor when the torque passes through zero is characterized by comprising the following steps of:

1) The method comprises the steps that wheel speed signals of the ABS are uploaded to a chassis CAN, the chassis CAN uploads rotating speed signals to a gateway, and the gateway uploads the wheel speed signals to an EV-CAN;

2) When the motor torque is zero, the MCU reads a real-time wheel speed signal through the EV-CAN, and according to a formula: the motor target rotating speed = the real-time wheel speed multiplied by the total speed ratio of the speed reducer, and the motor target rotating speed at the real-time wheel speed is obtained through calculation;

3) And correcting the MCU controller by using the target rotating speed of the motor, controlling the rotating speed of the motor by the MCU controller, and when the rotating speed of the motor is higher than the target rotating speed, performing torque control to reduce torque so as to reduce the rotating speed of the motor, or when the rotating speed of the motor is lower than the target rotating speed, performing torque control to increase torque so as to increase the rotating speed of the motor.

The NVH motor control method for the new energy automobile driving motor when the torque passes through zero has the beneficial effects that:

1. a NVH motor control method when the torque of a driving motor of a new energy automobile passes through zero is characterized IN that IN the switching process of TIP-IN and TIP-OUT, wheel speed signals pass through a chassis CAN, a gateway and an EV-CAN through ABS wheel speed signals, an MCU acquires the wheel speed signals when the torque of the motor passes through zero, the MCU acquires the motor rotating speed at the wheel speed as the target rotating speed of the motor after calculation, and the rotating speed is corrected by the rotating speed to control the rotating speed of the motor, so that the linear speed difference between a driving wheel and a driven wheel IN a meshing gear of a speed reducer is reduced, collision is reduced, and vehicle shake and the tooth knocking sound of the speed reducer are effectively reduced;

2. a NVH motor control method for a new energy automobile driving motor when the torque passes through zero is characterized in that a motor control strategy is optimized, hardware change is avoided, cost is not increased, the period is short, and the NVH problem when the torque of the driving motor passes through the zero is solved.

Drawings

FIG. 1 is a control flow chart of the uploading path of wheel speed signals and the correction of the rotation speed of a motor;

FIG. 2 is a schematic diagram of a situation that the motor speed fluctuates when a NVH motor control method is not adopted when the new energy automobile driving motor torque passes through zero;

FIG. 3 is a schematic diagram of the NVH motor control method when the torque of the driving motor of the new energy automobile passes through zero and the motor speed fluctuation condition;

Detailed Description

The present invention will be described in further detail with reference to the accompanying fig. 1-3 and the specific embodiments described herein, which are provided for illustration only and are not intended to limit the present invention.

As shown IN fig. 1, IN the overall vehicle TIP-IN and TIP-OUT switching process, a NVH motor control method when the torque of a driving motor of a new energy vehicle is zero is performed, an overall ABS wheel speed signal of the overall vehicle is uploaded to a chassis CAN, the chassis CAN is uploaded to a gateway and then uploaded to an EV-CAN by the gateway, when the torque of the motor is zero, an EV-CAN wheel speed signal is read, and the motor speed at the wheel speed is obtained through calculation as a target motor speed, the calculation formula is that the target motor speed = a real-time wheel speed × a total speed ratio of a reducer, the total speed ratio of the reducer = a main speed reduction ratio × a gear ratio, the MCU controller is corrected by the target motor speed to control the motor speed, the corrected speed is compared with the motor speed as the target speed, and then speed closed-loop control is performed, when the motor speed is higher than the target speed, torque control is performed to reduce the torque, the motor speed is decreased, when the motor speed is lower than the target speed, torque control is performed to increase the motor speed, so that the target speed and the difference between the target speed and the motor speed and the noise and the vibration are greatly reduced.

As shown in the attached drawing 2, the NVH motor control method when the new energy automobile driving motor torque passes zero is not used, the motor rotation speed fluctuation situation when the motor torque passes zero is shown schematically, the left ordinate is the torque, the right ordinate is the rotation speed, when the motor torque passes zero, the motor rotation speed fluctuation 120rpm can be seen from the attached drawing 2, the rotation speed fluctuation is large, the impulse is large when a gear collides, and the generated gear knocking sound and vibration of the speed reducer are also large.

As shown in fig. 3, when the NVH motor control method for driving the motor of the new energy automobile when the torque passes zero is used, the fluctuation condition of the motor speed when the motor torque passes zero is schematically shown, the left ordinate is the torque, and the right ordinate is the rotation speed, and as can be seen from fig. 3, when the torque passes zero, the fluctuation of the motor speed is 40rpm, the fluctuation of the rotation speed is small, the impulse during the gear collision is small, and the generated gear knocking sound and vibration of the speed reducer are also small.

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

Claims

1. The NVH motor control method is characterized by comprising the following steps of:

2) When the motor torque is zero, the MCU reads a real-time wheel speed signal through the EV-CAN, and according to a formula: the motor target rotating speed = the real-time wheel speed multiplied by the total speed ratio of the speed reducer, and the motor target rotating speed under the real-time wheel speed is obtained through calculation;

3) And correcting the MCU controller by using the target rotating speed of the motor, controlling the rotating speed of the motor by the MCU controller, and when the rotating speed of the motor is higher than the target rotating speed, performing torque control to reduce the torque so that the rotating speed of the motor is reduced, or when the rotating speed of the motor is lower than the target rotating speed, performing torque control to increase the torque so that the rotating speed of the motor is increased.