Enhanced Sliding Mode Control for PMSM Speed Drive Systems Using a Novel Adaptive Sliding Mode Reaching Law Based on Exponential Function

Sliding mode control is widely used to enhance the speed control performance of permanent magnet synchronous motors (PMSM). However, the slow reaching onto the sliding surface and chatting phenomena of conventional sliding mode reaching law (SMRL) is still a challenging issue. This article proposes a novel adaptive SMRL (ASMRL) to solve these problems. This ASMRL includes the system state variables, an exponential function term bounded by the absolute value of the switching function, and an adaptive switching gain term influenced by the convergence of the system state. This approach efficiently accelerates the velocity at which the system state reaches the sliding mode surface and effectively suppresses chattering. Then an enhanced sliding mode controller is designed for the speed regulation of PMSM systems. Finally, mathematical stability analysis, numerical analysis, simulation, and experimental validation are conducted to demonstrate the effectiveness of the proposed method.