Improved Quasi-3D Finite Element Method for an Axial Flux Permanent Magnet Motor

In the quasi-3D FEM, the overall performance of axial flux permanent magnet (AFPM) motor can be obtained by assembling 2-D FEM results of each cross section along a radial direction. A critical drawback of quasi-3D FEM is its inability to conduct finite element (FE) analysis when rotor back-iron and permanent magnet (PM) have different length along radial direction. In order words, because there is no PM in computation region of quasi-3D FEM when rotor-back iron is longer than PM along lamination direction, FE analysis cannot be done. To address this problem, we propose an improved quasi-3D FEM which considers AFPM motor with different length between rotor-back iron and PM. From results of the 3D FE analysis, the validity of the proposed method is verified.