Disturbance rejection in a brushless DC motor velocity control system using a variable structure controller

This paper presents a study of the performance of a brushless DC (BLDC) motor velocity control system. The system uses a variable structure controller in order to enhance the ability to reject external disturbances and internal nonlinearities. The motor and system equations inherently appear in a regular form and this simplifies the controller design. Chattering resulted from switching the controller structure is minimized by a continuously adaptive smoothing control command. Simulation results had shown an improved performance over cases with no switching and with constant switching magnitude on the controller structure.>