Discrete-time second-order integral sliding mode control for speed control of PMSM using the ultra-local model

The current study presents a novel discrete-time second-order integral sliding mode control (DSISMC) approach incorporating a finite-time stable observer for speed control of permanent magnet synchronous motors (PMSMs). Initially, an ultra-local model (ULM) is formulated for PMSM speed control, and a new finite-time stable observer is developed based on the ULM to estimate unknown dynamics. Subsequently, a DSISMC algorithm is introduced to enhance dynamic and steady-state efficiency, achieving desired speed control under disturbances. Theoretical analyses validate the realization of finite-time quasi-sliding mode. Finally, the proposed method is validated by comparing it with intelligent proportional integral and sliding mode controllers. Simulation and experimental results demonstrate the efficiency of the DSISMC algorithm.