Modified Sliding Mode Speed Control of Brushless DC Motor Using Quantized Current Regulator

This paper proposes a cascade control strategy, combined of a modified sliding mode controller and a quantized current regulator, for a brushless DC motor (BLDCM) to achieve high-performance speed control. In the current control loop, the quantized control law is derived by minimizing the instantaneous square value of a performance index signal using the theory of variable structure control to perform a fast current control. Then, a modified sliding-mode controller (SMC) with time-delay estimation is presented in its outer control loop to enhance the speed control without the need for the identification of system parameters or the estimation of the bounds of disturbances. Simulation results demonstrate the effectiveness of the proposed scheme under the influence of system uncertainties and disturbances.