The stator windings of brushless DC motors are mostly made into three-phase symmetrical star connection, which is very similar to three-phase asynchronous motors. The rotor of the motor has magnetized permanent magnets. In order to detect the polarity of the rotor of the motor, a position sensor is installed in the motor. The driver is composed of power electronic devices and integrated circuits. Its functions are: to accept the start, stop and brake signals of the motor to control the start, stop and brake of the motor; to accept the position sensor signal and the forward and reverse signals to control the reverse The on-off of the power tubes of the variable bridge produces continuous torque; accepts speed commands and speed feedback signals to control and adjust the speed; provides protection and display, etc.