Analysis on the Development of Electric Motor Drive Motors in China
1. Drive motor type and its development
The drive motor is a key component of the electric vehicle and directly affects the power and economy of the vehicle. The drive motor mainly includes a DC motor and an AC motor. At present, electric motors widely use AC motors, mainly including: asynchronous motors, switched reluctance motors and permanent magnet motors. The main features of each type of motor are shown in Table 1.
The development trend of automotive motors is as follows: permanent magnetization of the motor body: permanent magnet motors have the advantages of high torque density, high power density, high efficiency and high reliability. China has the world's most abundant rare earth resources, so high-performance permanent magnet motor is an important development direction of China's vehicle drive motor.
Digitization of motor control: The emergence of dedicated chips and digital signal processors has promoted the digitization of motor controllers, improved the control accuracy of motor systems, and effectively reduced the system size.
Motor system integration: through electromechanical integration and controller integration, it is beneficial to reduce the weight and volume of the drive system, which can effectively reduce the system manufacturing cost.
2. Foreign developments are based on foreign materials
In recent years, the electric buses developed by the United States and Europe mostly use AC asynchronous motors. The technical parameters of typical foreign products are shown in Table 2. In order to reduce the weight of the car, most of the motor casings are made of cast aluminum. The motor has a wide constant power range and the maximum speed can be The speed of the base is 2 to 2.5 times.
Most of the electric vehicles that Japan has introduced in recent years use permanent magnet synchronous motors. The product power level covers 3~123kW, the motor constant power range is very wide, and the maximum speed can reach 5 times of the base speed.