Forced field oriented control of induction motors with rotor and stator resistance estimation

This paper presents a forced field oriented control and filtering techniques for the estimation of rotor flux, rotor and stator resistance of a three-phase induction machine. The indirect field orientation scheme has been modified adding a PI controller so as to force the rotor flux field orientation when machine parameters are mistuned. The rotor flux is estimated by an extended Kalman filter in a synchronous reference frame. In order to make the system more robust against stator and rotor resistance mistuning, the stator resistance is also estimated by an extended Kalman filter. As for the rotor resistance estimation, it is performed based on the sensitivity model of the induction machine in a synchronous reference frame in conjunction with a closed-loop adaptation algorithm. Computer simulations (using Matlab/Simulink) have been carried out to test the performance of the proposed forced field oriented control scheme and filtering techniques. The simulations demonstrate that the modified indirect field orientation scheme is robust against machine parameter mistuning and state estimation errors. In addition simulation results show that the estimate of the rotor and stator resistance and rotor flux is accurate.