There are two types of motors used in electric vehicles, permanent magnet synchronous motors and AC asynchronous motors.
Notes on permanent magnet synchronous motors and AC asynchronous motors:
The working principle of a permanent magnet motor is to generate electricity to generate magnetism. When electricity is applied, the coils in the motor generate a magnetic field, and the coils start to rotate because the internal magnets of the same polarity repel each other. The greater the current, the faster the coil spins.
The advantage of using a permanent magnet synchronous motor is that it is small in size and light in weight, which can save a lot of space. In addition, the permanent magnet synchronous motor has excellent use efficiency, and its high power density makes the motor work efficiency reach 97%, which guarantees power and acceleration for the car. But the disadvantage of permanent magnet synchronous motors is that they are expensive and require rare earths as materials. As we all know, China has the world’s largest rare earth reserves, and China’s total output of magnetic materials has reached 80% of the world’s. Therefore, domestic electric vehicles basically use permanent magnet synchronous motors, such as BAIC New Energy, BYD , and Xpeng motors.
Although AC asynchronous motor can also be regarded as the principle of electromagnetism, it is different from permanent magnet synchronous motor in that it adopts the design of coil iron core. After electrification, a magnetic field appears, and as the current changes, the direction and magnitude of the magnetic field also change.
Although there is no high power of permanent magnet synchronous motor, the price of AC asynchronous motor is relatively low, so the cost control is ideal. However, the large volume also takes up a certain amount of space in the car, and the high energy consumption is also a major drawback, resulting in low operating efficiency. Therefore, AC asynchronous motors are widely used in new energy buses. In addition, Tesla is also one of the car brands that mainly use AC asynchronous motors.
At present, the development of motors is still in a bottleneck period that needs to be broken through. There is actually not much difference between permanent magnet synchronous motors and AC asynchronous motors. Like domestic brand electric vehicles, they focus on space, and the joint venture brand Tesla pursues more power, so they focus on using different motors.
Post time: Feb-04-2023