Adaptive Extended State Observer-Based Terminal Sliding Mode Control for PMSM System with Uncertainties

An adaptive extended state observer (AESO)-based terminal sliding mode control (ATSMC) is proposed for PMSM systems with uncertainty in this paper. Firstly, in order to handle various uncertainties explicitly and effectively, to divide the uncertainty into structured uncertainty (i.e., parametric uncertainty) and remaining uncertainty (i.e., external disturbance and unmodeled dynamics) two types is carried out. The former is handled by introducing adaptive parameter estimation (APE), and the latter is considered as lumped disturbance and compensated by extended state observer (ESO). In this way, the cooperation between parameter adaption and disturbance observer is established and the estimation accuracy of ESO is guaranteed under the parameter perturbation. Then, a terminal sliding mode function with fractional order is used to achieve system state finite-time convergence. Thus, a compound nonlinear controller is obtained by integrating different mechanisms. The main advantages of this controller are only the output feedback used, and strong disturbance rejection ability. Experimental results show the efficiency of the proposed method.