A novel sensorless control strategy for brushless DC motor drive based on fuzzy logic observer

This paper presents a novel sensorless control method of brushless DC (BLDC) motor based on a simple fuzzy logic observer. The inputs of this observer are measured values of line to line voltages and currents and its outputs are Back-EMF space vector components in the stationary reference frame. To determine the commutation instants, a new technique based on the sign of the Back-EMF space vector components is proposed. This method provides an accurate sensorless operation in wide speed range. The validity of the proposed method is verified through simulation.