Electric car uses wheel hub motor drive technology reasons
In the environment of environmental protection, electric vehicles have also become a hot spot in recent years. Electric vehicles can achieve zero or very low emissions in urban transportation, and have great advantages in the field of environmental protection. Countries are striving to develop electric vehicles. The electric vehicle is mainly composed of a motor drive system, a battery system and a complete vehicle control system. The motor drive system is a part that directly converts electric energy into mechanical energy, and determines the performance index of the electric vehicle. Therefore, the choice of the drive motor is particularly important.
Generally, an electric vehicle adopts a power system structure type driven by a concentrated motor.
Concentrated motor drive advantages:
(1) It is possible to use part of the transmission of the internal combustion engine powered vehicle, which is arranged in the original engine compartment with good inheritance;
(2) It can adopt the integrated structure of the motor and the speed reduction mechanism, and even the controller, and has a compact structure, which is convenient for handling problems such as motor cooling, vibration isolation and electromagnetic interference;
(3) The overall layout of the whole vehicle is close to the internal combustion engine, and the thermal management of the front compartment, sound insulation treatment and collision safety are close to or easy to handle.
Concentrated motor drive disadvantages:
(1) The transmission chain is long and the transmission efficiency is low;
(2) It is usually required to use high-speed and high-power motors, which have high requirements on motor performance.
Dispersion motor drive advantages:
(1) Using electronic differential control technology to achieve different speeds of internal and external wheels during cornering, and the accuracy is higher;
(2) Eliminating the mechanical differential device is beneficial to the power system to reduce the quality, improve the transmission efficiency, and reduce the transmission noise;
(3) It is beneficial to the optimization of the overall layout of the vehicle and the matching optimization of the dynamic performance of the vehicle;
(4) Reducing the performance requirements of the motor, and having the characteristics of high redundancy and reliability
Dispersion motor drive disadvantages:
(1) In order to meet the coordination of various rounds of motion, the requirements for synchronous and coordinated control of multiple motors are high;
(2) The distributed installation arrangement of the motor proposes technical problems in various aspects such as structural arrangement, thermal management, electromagnetic compatibility and vibration control.
Dispersing motor drives usually have two methods: hub motor and wheel motor. The so-called wheel motor mode means that each drive wheel is driven by a separate motor, but the motor is not integrated into the wheel, but is connected to the wheel by a transmission (such as a drive shaft). The drive motor of the wheel-side motor type belongs to the sprung mass range, and the suspension system has good vibration isolation performance. However, the motor mounted on the body has a great influence on the overall arrangement of the vehicle, especially in the case of rear axle drive. Moreover, due to the large deformation movement between the body and the wheel, the universal transmission of the transmission shaft also has certain limitations.
