Enhanced composite adaptive sliding mode reaching law for speed regulation in SPMSM

This paper presents an enhanced composite adaptive sliding mode reaching law (ECASMRL) for improving the dynamic speed accuracy of a surface-mounted permanent magnet synchronous motor (SPMSM) control system based on sliding mode control and disturbance compensation techniques. The key characteristic of ECASMRL is that it reduces the time required for the system trajectory to reach the sliding surface faster than the existing reaching law while effectively reducing chattering and providing notable performance. Moreover, an extended sliding-mode disturbance observer is utilized to estimate the unknown external disturbances and provide feedforward compensation to the SPMSM control system, reducing the additional chattering induced by the lumped disturbances and enhancing disturbance rejection capabilities. The stability of the proposed method is validated through the Lyapunov theory. Simulation results and comparisons with other approaches demonstrate the superior performance of the proposed reaching law.