A Winding Function-Based Model of Air-gap Eccentricity in Saturated Induction Motors

Abstract

This paper set out a new modeling technique of air-gap eccentricity in induction motors (IMs) taking into account teeth saturation due to the local air-gap flux concentration. The approach is based on the inclusion of the magnetic saturation into the analytical model by a fictive permeance variation. Besides that, it supposes that, in air-gap nonuniformity conditions, the well-known saturation factor must be updated in function of the spatial-dependant air-gap length. The 2D-modified winding function approach (2DMWFA) is utilized to get the inductance formalism while assuming a linear rise of the saturation factor with respect to the air-gap length in a particular circumferential region. We show that the proposed model yields more reasonable results by confirming that the magnetic saturation effect reduces the asymmetry of the air-gap flux distribution due to the eccentricity. Furthermore, we highlight this effect by inspecting the shapes of the calculated inductances and making them ready for a full dynamic simulation in sense of multiple coupled circuit model (MCCM).