Brushless DC motor is composed of motor body and driver, which is a typical mechatronics product. Its working principle is that the permanent magnet is used as the rotor, the AC signal is input to the motor by power electronics technology (frequency converter), the frequency of the rotating magnetic field of the stator is controlled, and the rotating speed of the motor rotor is fed back to the control center for repeated correction, so as to achieve a way close to the characteristics of DC motor.

Brushless motor refers to the motor without brush and commutator (or slip ring), also known as commutator-less motor. As early as the nineteenth century, when the motor was born, the practical motor was brushless, that is, AC squirrel-cage asynchronous motor, which was widely used. However, asynchronous motor has many insurmountable defects, which leads to the slow development of motor technology. Transistor was born in the middle of last century, so DC brushless motor with transistor commutation circuit instead of brush and commutator came into being. This new brushless motor is called electronically commutated DC motor, which overcomes the defects of the first generation brushless motor.