Equivalent disturbance observer based discrete-time integral sliding mode control for PMSM speed regulation system

In order to improve the speed-regulation performance of the permanent-magnet synchronous motor (PMSM) system under uncertainties and disturbances, an equivalent disturbance observer (EDO) based discrete-time integral sliding mode control (DISMC) scheme is proposed. To avoid the high-frequency noise caused by the differential terms of conventional sliding mode control (SMC), a discrete-time integral sliding surface is designed, which can eliminate the reaching phase and achieve excellent tracking responses and global robustness. Then, a discretized EDO is proposed to realize the estimation and feed-forward compensation of the disturbances online, so that it can guarantee disturbance rejection ability and high-precision control. Furthermore, stability analysis of the designed system is given. Simulation results demonstrate the validity of the proposed control scheme.