Self-tuning control for current loop in a Switched Reluctance Motor drive

Abstract

This paper describes the development of a self-tuning control scheme applied to the current loop of a Switched Reluctance Motor (SRM) drive for trajectory tracking. The proposed control technique is based on the minimization of a modified version for the quadratic performance index, which includes an additional weighted derivative term. The self-tuning control action is implemented using a recursive identification procedure with a covariance matrix reset scheme in order to find optimum parameters for the process. The proposed method is simulated and compared with the conventional PI controller, so often found in this kind of system, and also Ziegler-Nichols (ZN) tuning method. It must be mentioned that conventional PI and PID controllers are only able to assure optimum performance around a fixed operation point, as they have proven to be inadequate to compensate for parametric uncertainties, oscillatory dynamics, and other eventual changes in the system itself. A hardware prototype is then implemented and experimental results regarding the SRM drive show that the self-tuning controller provides a significant improvement in the system behavior, with setpoint tracking and increase the torque ripple damping.