Finite-Element Analysis of Rotor Slotting Saliency in Induction Motors for Sensorless Control

This paper deals with induction machines analysis by finite-element analysis (FEA) for position sensorless control drives based on rotating voltage carrier injection. In details, it focuses the analysis of the supply conditions of the machine, both the high-frequency rotating voltage carrier and the fundamental frequency supply, for the optimal detection of the rotor slotting saliency effects. With this regard, as an index for evaluating the response of the machine to the high-frequency carrier, the relative spatial harmonic of the stator inductance space-vector responsible for the rotor slotting effect has been chosen. A methodology for retrieving the stator inductance space-vector from the three-phase stator flux linkages and currents, computed by FEA, is proposed as well. Results of the variation of the rotor slotting spatial harmonic of the stator inductance with the carrier frequency and the rotor flux linkage are presented.