Position Detection Methods of Position Sensor-Less Brushless DC Motor

Abstract

With the widely use of Permanent Magnet Brushless DC Motor (BLDCM) in many fields, the superiority in the control method of position sensor-less is more and more obvious. In this paper several control methods of position sensor-less for BLDCM are presents, and a novel technique, the method of speed-independent position function, is introduced to detect the rotor position of BLDCM. This method may detect the rotor position from almost zero speed to high speed, and may also give the commutation time.