Sensorless BLDC Control

BLDC (Brushless Direct Current) motors have a lot of advantages, such as high torque, high power density, etc. Compared with the former motors, the reliability and endurance of BLDC motors are much better. However, it is necessary that the rotor and the stator should be synchronous, so one or more position sensors are needed in the control system. But the sensors reduce the life of BLDC motors, raise the cost and even limit the application field of BLDC motors. Because of these disadvantages of the sensors, a theory on sensorless control is brought forward to communicate between the rotor and the stator on synchronous running.This paper is especially on permanent magnetic BLDC motors control. The BEMF of BLDC is sensed by the high speed ADC module in dsPIC30F2010, which is a high performance DSC. In this way, the rotor and the stator will communicate to be synchronous. Additionally, a high speed PID routine is running to improve the controlling accuracy powered a separated DSP engine in this DSC.