Tracking Control for Sensorless Induction Motors with Uncertain Load Torque and Resistances

Abstract

The rotor speed and flux modulus tracking problem for sensorless induction motors with uncertain constant load torque and uncertain both rotor and stator resistances is addressed. A new ninth order dynamic nonlinear adaptive control algorithm is designed: it relies on a novel closed loop observer for the unmeasured state variables (rotor speed and luxes) which is adaptive with respect to the uncertain parameters (load torque and motor resistances). Local exponential stability of the origin of the closed loop tracking and estimation error dynamics is guaranteed under suitable conditions including persistency of excitation which depends on reference signals only.