Passivity based voltage controller-observer design with unknown load disturbance for Permanent Magnet Synchronous Motor

This paper introduce a design strategy that utilizes the passivity concept in order to develop a combined controller-observer system for Permanent-Magnet synchronous Motor (PMSM) speed control using only rotor position measurement and voltage applied to stator windings. The load torque is unknown, therefore it must be estimated. To this end, first a desired energy function for the closed loop system is constructed, and then a combined controller-observer system is constructed such that the closed loop system matches this energy function. A damping term is included to ensure asymptotic stability of the closed loop system. The interesting feature of this approach is the fact that it establishes a duality concept between the controller and observer design strategy. Such a duality feature is unique for non linear systems. Simulation tests on the combined controller-observer design and adaptive law to estimated load torque are provided to show the feasibility and the performance of this method.