Fuzzy gain scheduling PI controller for a sensorless four switch three phase BLDC motor

A sensorless method for six-space-vector four Switch three phase BLDC motor driver is described in this paper. Due to the nature of low resolution of position sensing, the speed feedback is variable sampling. A fuzzy gain scheduling PI controller is proposed in this paper. It is based on three selected PI controllers in fixed sampling time intervals, high-, median- and low-speed, and combined by simplified fuzzy logic. The experimental results are provided to show this controller is efficient and workable.