The Induction Motor MRAS-Based Speed Estimator Capable of Modelling the Slip Frequency Dependent Variability of the Rotor Impedance

Speed feedback is indispensable not only for closed-loop controlled induction motors (IM) but also the state monitoring systems of open-loop IMs. Replacing speed sensors with estimations has many advantages including, e.g., hardware complexity reduction, sensor cabling elimination, and reduction IM drive costs. From various methods estimation proposed in literature, model reference adaptive system (MRAS)-based estimator stands out because its straightforward synthesis technique lower computational complexity. On other hand, this inherently sensitive to mismatching equivalent circuit parameters. During transients, when slip frequency cannot be temporarily over assumed operating point, rotor impedance varies changes. This phenomenon even more significant high-slip IMs (NEMA design D IMs), which operate under cycling load like in, oil well pumps. The rate range variability are related Therefore, a capable modelling dependent may required, particularly paper presents an MRAS-based developed on space vector modelled by parallel connected branches series resistance leakage inductance. experimental test results confirm precise tested achieved devised considered indicate potential industrial application.