Speed tracking control of a permanent-magnet synchronous motor with state and load torque observer

This paper is concerned with the speed tracking control problem for a perma nent-magnet synchronous motor (PMSM) in the presence of an unknown load tor que disturbance. After a brief review of the mathematical model of the PMSM , a speed tracking control law using the exact linearization methodology is introduced. The tracking control algorithm is completed by adding an exten ded observer which provides, on the one hand, the motor speed and accelerat ion and, on the other hand, estimates the unknown load torque. The stabilit y of the closed-loop system composed of a nonlinear speed tracking controll er and an observer is studied by the way of Lyapunov theory. Furthermore, t he decoupling of the state observer and the load torque observer is discuss ed. Finally, a real-time implementation and the experimental results of the proposed control strategy are presented.