DC Brushless Motor’s Structure and Function

Brushless DC motor, which is made up of a drive and the electric motor, is a typical electromechanical product. The stator winding of the electric motor is wye connected triphase symmetrically which is very similar with three-phase asynchronous motor.

brushless dc motor

brushless dc motor

The rotor of the motor is stuck with a permanent magnet which has been magnetized. A position sensor is equipped in the motor in order to detect the polarity of the rotor. The drive is constituted by power electronic devices and integrated circuit. It has four main functions as following. First, a drive receives the signal when the motor starts, stops and brakes in order to control the motor correspondingly.

Second, it receives the position sensor signal and a positive reversal signal to control the switch of the inverter’s each power transistor and produce continuous torque. Third, it receives the speed command and speed feedback signal to control and adjust the speed. Fourth, it provides protection and display space.