Novel sensorless PWM-controlled BLDCM drives without using position and current sensors, filter and center-tap voltage

The main theme of this paper is to present a novel sensorless brushless DC motor (BLDCM) drive without using position and current sensors, filter and center-tap voltage. The techniques for this drives, include initial position detection technique [Y.S. Lai et al., April 2003], loss-reduction PWM technique [Y.S. Lai et al., Oct. 2002], and back-EMF detection technique [Renesas Systems Solutions Asia Pte. Ltd., Sept. 2002]. The initial position detection technique provides initial position detection without using A/D converter, filter, current sensors, and hall sensors as shown in [Y.S. Lai et al., April 2003]. The PWM technique [Y.S. Lai et al., Oct. 2002] significantly reduces the conduction losses by invoking the concept of synchronous rectifier. The back-EMF detection technique offers noise-free back-EMF detection results for commutation control of inverter, while not using any filter and center-tap voltage. Experimental results derived from a DVD spindle BLDCM test system confirm the theoretical analysis.