Sliding Mode Control with High-Order Disturbance Observer Design for Disturbance Estimation in SPMSM

This study proposes high -order disturbance observer (HODO) SMC method along with HODO load torque observer to control speed of SPMSM system under speed and load torque variations has been proposed. Firstly, dynamic system of the SPMSM has been formulated. Secondly, switching feedback control law with use of continuous approximation of sliding surface to avoid chattering effect has been used. Thirdly, the proof of reachability condition has been demonstrated. Finally, for estimation of load torque variation HODO observer has been integrated to the control system. The simulation results have been shown significant improvement of performance for both, under nominal parameters and model uncertainties than with conventional PI-PI method.