Influence of Magnetic Properties on the Performance of Dual Stator Electric Machine: Part II

Abstract

Magnetic properties such as magnet coercive force and magnetic remanence have significant impact on the electromagnetic performance of an electric machine. Thus, detailed analysis on the characteristics of these magnetic properties for better understanding of precise magnet material selection is demonstrated in this work. The investigated machine features include: torque-speed profile, total harmonic distortion (THD), torque ripple and winding inductances. Maxwell-2D finite element software is used in the analysis. It is shown that the investigated machine type having neodymium magnet has the most admirable qualities such as larger output torque, higher saturation-withstand potential than others, etc. Moreover, it is observed that the investigated machine output torque is more or less generated by its magnetic torque component with insignificant contribution made from the reluctance torque constituent. More so, the results reveal that there is an inverse relationship between the coercive forces of a given electric machine and its resulting winding inductance magnitudes. The estimated maximum quadrature-axis inductance of the investigated machine is: 0.6275 mH, 0.5567 mH, 0.3760 mH and 0.2873 mH i.e. from alnico, ferrite, SmCo and NdFeB magnets, respectively, with the following corresponding coercive force: 230 kA/m, 303 kA/m, 796 kA/m and 1063 kA/m, respectively. Above all, electrical machine designers could through this analysis have better understanding on the right choice of magnetic material, which invariably depends on specific application.