Reactive Power MRAS for Rotor Resistance Estimation Taking Into Account Load-Dependent Saturation of Induction Motor

The accuracy of induction motor (IM) drive with employed field-oriented control depends on precise identification of the IM equivalent circuit parameters. Those parameters can change significantly during the drive operation. Therefore, an adaptation of the IM model parameters is needed for a high-performance drive. Estimators based on model reference adaptive system (MRAS) are not computationally demanding, but they a priori exhibit sensitivity to the other, non-estimated parameters. This paper analyses the influence of the proper knowledge of the magnetizing inductance on the accuracy of the rotor resistance estimator based on the traditional reactive power MRAS. The paper also takes into account the load-dependent saturation of the IM, which is often omitted during the analysis and shows that the implemented load-dependent magnetization characteristic improves the MRAS and drive performance. Simulation and experimental results conducted on 12 kW IM are presented.