A Novel Winding Design for EV Traction Electric Motors: Hybrid Hairpin Winding Layout Containing Both Copper and Aluminum Windings

Emerging design considerations for future electric vehicle traction machines prioritize innovative hairpin winding designs that deliver superior electro-magnetic performance across a wider speed range while maintaining lightweight construction and cost-effectiveness. To address this challenge, incorporating aluminum as the winding material presents a viable solution due to its lightweight and cost-effective nature however, overcoming its higher ohmic losses, while meeting the higher performance targets remains a main critical obstacle to be addressed. In this respect, utilizing the analytical models: winding function-based model, and winding's AC loss estimation model, this paper proposed a novel hybrid hairpin winding design layout that combined the integer slot distributed windings (ISDW) and variable pitch concentric winding layouts for a commercially available traction machine. The hybrid winding layout incorporates both copper and aluminum windings, resulting in a reduction of 36.1% in winding weight and 46.6% in cost compared to the conventional ISDW design windings with only copper. Additionally, the hybrid winding layout exhibits higher electromagnetic performance including output power, torque, and efficiency, over wider speed range, encompassing both the maximum torque per ampere and field weakening regions