Prediction of slotting saliency in induction machines with respect to high-frequency-excitation based sensorless control

Sensorless field oriented control (FOC) strategies have found their place in industry applications during the last few years. Stimulated by this development scientific research continues to improve their performance, which is directly linked to the estimation accuracy of flux and rotor position without a mechanical sensor by means of high frequency or transient excitation. The influence of induction machine (IM) design parameters on the rotor saliency, originating from interactions of rotor and stator slotting, is investigated with a focus on transient electrical machine behavior. As this saliency is often used to estimate rotor position in sensorless control schemes, effects attenuating or sustaining it have a straight impact on the control´s quality. The present study features finite element (FE) simulations that are compared to measurements for a number of test machines, to validate the results. In a second step it aims at generating a more comprehensive view on the dependencies between saliency and machine design by conducting parameter variations by means of FE simulations, with a focus on stator short pitching and rotor skewing.