Current Distortion Rejection in PMSM Drives using an Adaptive Super Twisting Algorithm

Abstract

Unavoidably any permanent magnet synchronous motor (PMSM) control system is subjected to perturbations, such as motor nonidealities, inverter nonlinearities, and parasitic load. To reject the PMSM perturbations, a new variant of an adaptive super twisting, ST, controller is proposed in this paper. In this algorithm, a proportional integral, PI, control and a ST control are adaptably combined using the rotor speed. Thus, the proposed algorithm is called speed adaptive super twisting, SAST. Furthermore, a novel mathematical procedure is presented to relate the chattering amplitude and the PMSM perturbations to the SAST design. The main contribution is the SAST application to reduce the stator current total harmonic distortion, THDi. By comparing the SAST control against PI control, the THDi is reduced from 9.9 per cent to 1.27 per cent, in simulation, and the THDi is reduced from 22.79 per cent to 1.56 per cent, experimentally. These results validate the SAST design and demonstrate how the SAST is an excellent alternative to reject the unavoidable perturbations that commonly effect the stator current waveform of any PMSM.