1. Overview of electric drive system
The electric drive system is the heart of a pure electric vehicle. It converts electrical energy into mechanical energy to drive the vehicle. The main difference from the traditional power system is that the power source is replaced by an electric motor. The clutch, transmission, drive shaft and drive axle in the traditional drive system are assemblages. The components are simplified in different types of electric drive assemblies.
The electric drive system is composed of a drive motor, a motor controller and a speed reduction mechanism, and is connected to other systems of the vehicle through a high and low voltage wiring harness and a cooling pipeline. Its function is to efficiently convert the energy of the power battery into the kinetic energy of the wheels under the control of the driver, or to feed back the kinetic energy of the wheels to the power battery.
Compared with the traditional drive system assembly, the electric drive system has the characteristics of small size, high power density, and small layout space requirements. There are three modes: wheel drive, rear wheel drive and four-wheel drive.
There are two main types of driving methods for pure electric vehicles: centralized driving and distributed driving.
① Centralized drive has small changes to the vehicle itself, short development cycle, and low difficulty. It is currently the mainstream drive system of pure electric vehicles. Among them, cars mostly use a single motor + reducer/transmission system, and passenger cars mostly use a system that connects the motor to the axle. . The key components of the centralized drive system are developing from a split to an integrated type. In-depth research is needed on the deep integration of the motor system with the reducer/transmission and the drive axle to improve the level of processing and manufacturing.
②The distributed drive transmission chain is simplified, the space utilization rate of the whole vehicle is high, and the power performance and control performance are superior. With the continuous improvement of motor integration and control technology and the further improvement of vehicle layout space requirements, the distributed drive configuration will be the development direction of pure electric vehicles.