Comparison of Bar-Wound Windings Permanent Magnet Machine with Different Cross-Sectional Shape for Hybrid Electric Vehicle

Nowadays, the interior permanent magnet (IPM) machines, which particularly use the bar-wound windings for hybrid electric vehicle (HEV) application have drawn more and more attention due to their high torque density, high efficiency, better heat dissipation and lower acoustic noise, etc. However, the machines suffered the big AC losses especially at the high speed condition due to their bigger bar conductor cross-sectional dimensions compared to the stranded windings. In this paper, three bar-wound windings IPM machines, which having the equal bar conductor cross-sectional area, slot fill factor, steel diameter, stack length and magnet usage, except that the bar conductor cross-sectional shape is different, are compared and analyzed by finite element analysis (FEA). It is demonstrated that the bar-wound windings IPM machine using the more flat cross-sectional shape of bar conductor, have the minimized AC losses especially at the high speed condition. What's more, other performance such as the power density, torque density, efficiency and flux-weakening capability is the superior.