Design of an adaptive terminal sliding mode to control the PMSM chaos phenomenon

This paper schemes a new nonlinear method for controlling and suppressing of chaos instability in the PMSM. First, a nonlinear model of PMSM is considered that is able to describe the dynamic behaviour of the PMSM in different functional conditions, including the occurrence of chaos. As an integral part of most physical systems, disturbance with an unknown upper limit is considered in the design of the control scheme. Parametric uncertainty is also included in the PMSM system model and a new control technique is presented based on robust adaptive and sliding mode approaches to prevent chaos. In the proposed method, adaptive technique is used to estimate the upper bound of uncertain terms, disturbances and nonlinear terms, and the robust sliding mode scheme is designed to stabilize the closed-loop PMSM system in contradiction of chaos. Using comparisons, the efficiency of the proposed method is shown in different working conditions.