The role of the motor is to convert the power of the power supply into mechanical energy, through the drive or direct drive wheels and work devices. Today's electric car is widely used DC series motor, this motor has a "soft" mechanical properties, and the car's driving characteristics are very consistent. However, with the development of motor technology and motor control technology, the DC motor is expected to be driven by the DC brushless motor (BCDM), the switched reluctance motor (SRM) and AC asynchronous motors.