Line current spectrum analysis in saturated three-phase cage induction machines

Abstract

The paper deals with modeling of saturated induction machines aimed at current signature analysis. The numerical model takes into account saturation of the main magnetic flux path using the concept of the air-gap permeance modulation. The modified winding function theory is applied in order to calculate all the winding inductances in the machine. An alternative method for calculation of mutual stator–rotor inductance, which avoids the need for using two-dimensional look-up tables is proposed. The proposed approach significantly simplifies the implementation of the already complex model. Derived analytical expressions for self and mutual inductances of the rotor loops, as well as their derivatives, additionally simplify model implementation. The results from numerical model are experimentally verified. Experimental results confirm presence of all of the harmonics predicted by the model.