Improved Predictive Current Control of IM Drives Based on a Sliding Mode Observer

Abstract

In the conventional finite control set-model predictive current control (FCS-MPCC) method, both stator current and flux-linkage vector need to be computed for delay compensation and coordinate transformation. And, the conventional PCC is sensitive to rotor parameter mismatches. Additionally, the performance of FCS-MPCC degrades during speed variation when low-pass filter is applied to attenuate noise in speed measurement. In this paper, a reduced-order sliding-mode current observer (RSCO) is designed, which can predict stator current at the next sampling instant while simultaneously estimating the back electromotive force. With the help of RSCO, current prediction and coordinate transformation can be achieved without calculation of flux-linkage vector, which features simplicity in practical application. Additionally, robustness against parameter mismatch is significantly improved due to the feedback of current estimation error. Simulation and experimental results are presented to validate effectiveness of the proposed method.