Indirect Field Orientation Control of Induction Machine With Detuning Effect

Abstract

Induction motors (IM) arc characterized by complex, highly nonlinear time varying dynamics and inaccessibility of some states and outputs for measurements and hence may be considered as a challenging problem. Field orientation control (FOC ) methods of an induction machine achieve decoupled torque and flux dynamics leading to independent control of torque and flux as for separately excited DC motor, but there are sensitive to motor parameter variations. The present work select the indirect field orientation control (IFOC) as an effective method for eliminating the coupling effect. The results showed how well the drive performance has been improved by this control strategy. However, to what extent the control strategy can perform the decoupling relies on the accuracy of the slip frequency calculation. Unfortunately, the slip frequency depends on the rotor time constant that varies continuously according to the operational conditions and then the coupling effect may again arise. This paper investigates the improvement in the performance of the induction machine dynamics as the IFOC technique is utilized. Also, it investigates the degradation in dynamic performance when the rotor resistance is deviated from its nominal value.