Sensorless Control Strategy of PMSM with Disturbance Rejection Based on Adaptive Sliding Mode Control Law

A sensorless control strategy of permanent magnet synchronous motor (PMSM) with disturbance rejection based on an adaptive sliding mode control law (ASMCL) is proposed in this article. Firstly, an ASMCL is proposed to restrain the chattering of system state while maintaining fast convergence. The finite-time convergence of the ASMCL is proved and the convergence time is independent of the initial state of the system. Next, an improved sliding mode observer (SMO) based on the ASMCL is designed to restrain the chattering of the estimated back ElectroMotive Force (EMF). Afterwards, to improve the ability of suppressing the load disturbance, a disturbance observer on the ground of integral sliding mode control (ISMC) method is presented to gain the observed disturbance current for the feedforward compensation. Further, through the introduction of the ASMCL, an adaptive disturbance observer is proposed to suppress the chattering phenomenon caused by the symbolic function in the constant coefficient disturbance observer. The stabilities of the SMO and the disturbance observer are analyzed according to the Lyapunov stability theory. Comparative experimental results are given to verify the effectiveness of the proposed sensorless control strategy on a surface-mounted PMSM.