Comparative Analysis of Hairpin and Litz Wire Windings in High-Efficiency Electric Vehicle Motors

This paper compares hairpin windings (HPW) and litz wire windings (LWW) in a radial flux permanent magnet machine, focusing on alternating current (AC) resistance. HPW offers high fill factors but suffers from AC losses at higher frequencies. LWW reduces AC losses due to its stranded structure but has higher direct current (DC) resistance. Simulations explore LWW performance in various production variants and strand diameters, and quantify the influence of short-circuited wires. The study highlights LWW’s potential for optimizing stator winding designs for higher efficiency.