3D On-Load Analytical Modeling of Iron-Core Axial-Flux Permanent-Magnet Synchronous Motor Through Coordinate Transformation

This paper presents a novel 3-dimensional coordinate transformed layer model (3D CTLM) for iron-core axial-flux permanent magnet synchronous motors (AFPMSMs). The proposed 3D CTLM initially transforms the cylindrical geometry of AFPMSMs into a 3D Cartesian coordinate system. The core advantage of such transformation lies in its ability to simplify complex 3D electromagnetic equations while maintaining the essential 3-dimensional field effects such as radial fringing and leakage fields. The equivalent transformation can be achieved using the 3D magnetic vector potential to represent on-load conditions and geometry functions, which account for the diverse permanent magnet and coil shapes. In addition, to overcome the non-homogeneous material problems due to iron-core teeth, a permeability matrix is utilized. The proposed modeling method is validated extensively by parametric studies, achieving an accuracy higher than 97 % with two orders of magnitude faster in terms of calculation time as compared to a commercial FEA software. The validation manifests that the proposed modeling method is rapid and accurate enough to be used in the initial design and optimization phase of iron-cored AFPMSMs.