Composite chattering-free sliding mode control of chaotic permanent magnet synchronous motors

A composite chattering-free sliding mode control (CCF-SMC) scheme is presented for chaotic permanent magnet synchronous motor (PMSM) systems with some immesureable states. Through a simple coordinate transformation, the chaotic PMSM model is transformed into a Brunovsky canonical form, which is more suitable for the sliding-mode controller design. In order to estimate the unknown states and uncertainties, a nonlinear extended state observer (NESO) is developed and thus the restriction that all the system states should be completely measurable is avoided. Then, a full-order sliding mode controller is designed based on the NESO to ensure the convergence of all the system states without the chattering phenomenon. Comparative simulations are given to show the effectiveness and superior performance of the proposed control scheme.