A novel SMC-fuzzy speed controller for permanent magnet brushless DC motor

This paper presents a novel SMC-fuzzy speed controller for permanent magnet brushless DC motor (BLDCM). The proposed controller employs only the signal of speed error, avoiding the sensitivity to the noise of the acceleration signal as in the conventional sliding mode controller (SMC). It is composed of an equivalent control term, a switching term and a fuzzy control term. The sliding mode controller that is made up of the former two terms ensures the system´s stability. The SMC´s chattering phenomenon is eliminated by varying its control continuously according to the distance of the system states from the sliding surface. While the fuzzy control term improves dynamic response and decreases the steady-state error in the boundary layer. Simulation results show the proposed controller is better than the conventional SMC controller with a boundary layer. The experimental results demonstrate the high performance of the proposed controller.