Position and Speed Sensorless Control Medthod for Salient-Pole Brushless DC Motor with Estimated Values Correction

Abstract

In this paper, a sensorless control drive of a salient-pole brushless DC motor with an estimated values correction is proposed. In the system, the position angle and the speed at a rotating condition are estimated basically by the model reference adaptive system (MRAS). At an initial or a starting condition, the position angle is estimated by a new AC current injection method. And at a lower speed region, the estimated position angle and the speed obtained from the MRAS are corrected with a new correcting technique. The position angles and the speeds which were estimated values by the MRAS and the AC current injection method are compared and corrected effectively on the correcting system. The experimental results of the estimated position angles or the speed and the variable speed control with the experimental system are shown in the paper. From these results, the proposed sensorless speed control system may be applicable to as a practical use sensorless brushless DC motor drive system.