FEM analysis of a non-conventional axial flux hybrid excitation motor under flux weakening operation for electric vehicle purpose

This paper presents a study of a different kind of axial flux machine (HEBAFM) that uses a hybrid excitation brushless system in order to operate at flux weakening region for electric vehicles application. To analytically determine the flux densities in each part of the machine, a magnetic equivalent circuit was prepared. Then, FEM analyses were carried out so as to compare to the analytical method. In this type of machine, due the greater disc diameter, the ratio of speed of the topology proposed was 600/1200 revolutions per second to avoid vibration of the machine, i.e., ratio of speed of 1:2 and therefore the air gap flux density ratio adopted was 2:1. The main goal in this kind of design is keeping the magnetic induction of the topology under the saturation point in order to obtain a range of speed required for the application. The results from the analytical method and via FEM analysis are shown at the end of this paper.