Digital Sliding-Mode-Based xy-Current Suppression in Dual Three-Phase PMSM Drives

This paper presents a digital sliding-mode-based current regulator for the suppression of the undesirable circulating currents in a dual three-phase (DTP) permanent magnet synchronous machine (PMSM) drive. Due to their high frequency variation in synchronous reference frame and non-linear inductance variation, the suppression of the circulating currents is a challenging task. Following the principles of digital sliding-mode control, the proposed controller is capable of effectively suppressing the circulating currents. The performance evaluation of the proposed controller is performed in two modes, viz, equivalent control law based and equivalent control law with disturbance compensation. The former ignores the effect of inherent disturbances while the latter uses a simple unit time-steps delayed disturbance approximation. In this paper,the performance of both methods is compared to a conventional PI regulator in MATLAB/Simulink, and simulation results are verified experimentally. It is proved that the two proposed methods have better performances compared with PI controller.