Adaptive estimation of rotor time constant for indirect field-oriented induction motor drive

A novel estimation model based adaptive control for indirect field-oriented induction motor drive is presented. A new coordinate reference frame is utilised to describe the dynamical model of an induction motor. Then, the new reference frame based estimator is proposed to adaptively estimate the redefined state variables and the rotor time constant, necessarily used in indirect field-oriented control. Moreover, a modified estimation model also based on the same reference frame is further presented to simplify the estimation and adaptation computation. By utilisation of the estimation approach, robust indirect-fieldoriented control with respect to rotor time constant variation due to the effect of thermal changes is obtained. Finally, simulation and experimental results demonstrate the validity of the approach for practical applications.