Sensorless Control Technique using Third Harmonics Voltage Component of PM Brushless DC Motor

브러시리스 직류전동기의 3고조파 전압성분을 이용한 센서리스 제어기법

This paper studies particularly applicable method for sensorless Permanent Magnet Brushless DC(PMBLDC) Motor drive system. The waveform of the motor internal voltages (or back emf) contains a fundamental and higher order frequency harmonics. Therefore the third harmonics. component is extracted from the stator phase voltage. The resulting third harmonic signal keeps a constant phase relationship with the rotor flux for any motor speed and load condition. In addition, a simple starting method and a speed estimation approach are also proposed.