Composite Adaptive Position Control and Rotor Time Constant Estimation for Induction Motors Based on Passivity Theorem

This paper presents the passivity-based position control of induction motors by using the composite adaptation scheme. Firstly, a current model rotor flux observer estimates the flux, and then the adaptive laws estimate the inverse rotor time constant, moment of inertia, viscous coefficient, and load torque of a motor. The passive properties of the negative feedback connection of the flux observer to the inverse rotor time constant estimator, and the composite adaptive controller are analyzed by the passivity theorem. According to the properties, the position control system is proved to be globally stable. Experimental results are finally provided to show that the proposed method is robust to variations of the motor parameters. Furthermore, good output response and parameters estimating characteristic can be obtained.