Comparative Performance Analysis of Copper and Aluminum Wound Fractional–Slot PMSMs for High–Speed Traction Application

This paper performs a comprehensive comparative analysis of copper and aluminum wound permanent magnet synchronous machines (PMSMs) for high– speed application. While general studies have been conducted in literature on copper and aluminum windings in terms of conductivity, losses and mass density, the impact of these winding materials on the overall machine performance has not been analyzed broadly. Thus, this paper considers a fractional– slot wound PMSM developed for high–speed traction application and analyzes the performance with copper and aluminum windings in terms of torque density, peak efficiency, operating speed range and variation of winding losses with temperature. Furthermore, in order to assess these machines traction capability, a drive–cycle based analysis is conducted for common drive cycles including urban, highway and worldwide lightweight test cycle (WLTC) for a commercially available Ford Focus vehicle. Performance characteristics in terms of torque–speed characteristics and maximum energy density efficiency were compared for both machines.