Robust Speed Controller Using Dual Adaptive Sliding Mode Control (DA-SMC) Method for PMSM Drives

A robust mechanical parameter estimation together with adaptive speed control algorithms for permanent magnet synchronous motor (PMSM) drive systems based on the dual adaptive sliding-mode method is proposed in this paper. First, a robust adaptive sliding mode mechanical observer (RASM) and mechanical parameter identification (MPI) are proposed to eliminate system parameter errors in the first rotation. Based on RASM-MPI, the correct mechanical parameters are estimated from the system disturbance value. Then, an adaptive sliding-mode speed control (ASMSC) is applied to reduce the chattering inherent in the control signal and improve the convergence time to reach the sliding-mode surface. From the second rotation, the RASM identifies unknown external load torque and provides feed-forward compensation for the ASMSC to improve the speed control of the PMSM. All the proposed methods are applied to an industrial motor drive. The experimental results verified that the proposed scheme can estimate system parameters accurately within a short time. In addition, the speed controller can run stably, and with less error.