Sensorless brushless DC motor drive for air-conditioner compressor

Brushless DC motors (BLDCM) conventionally require position sensors to generate proper commutation instructions. Due to the high temperature environment, BLDCM in air-conditioner compressor requires a robust speed control without rotor position sensors. In this paper, a novel hybrid solution was presented to achieve reliable sensorless rotor position detection with relative concise and low cost circuit as well as little software expense. Experimental results shows that the schemes implemented are workable and the performance achieved are satisfactory.