Quasi 3D modeling of the magnetic forces in axial flux PM machines with rotor eccentricity

Abstract

In this paper, an analytical quasi 3D analysis is used to model unbalanced magnetic forces in an axial flux permanent magnet machine (AFPMM) under static eccentricity (SE) condition. Accurate modeling of the magnetic forces in AFPMMs requires three-dimensional (3D) finite element method (FEM). However, 3D FEM is generally too time consuming. Quasi 3D modeling method gives the ability to reduce the time and size of computations by transforming 3D geometry of an AFPMM to several 2D models. Using quasi 3D modeling, the air-gap length, magnetic flux density and magnetic forces are modeled under SE by analytical equations. The results given by proposed method is compared to 3D FEM results and it is shown that this results are accurate enough to evaluate magnetic forces. Moreover, using this method is significantly less time consuming process than 3D FEM simulation process.