Losses and Thermal Behavior of Multi-phase MW-Class PM Machines Employing Different Hairpin Winding Configurations

This paper investigates the differences in losses between conventional U-shaped hairpin windings and continuous hairpin windings (CHW), together with the corresponding impact on the thermal behavior of multi-phase, MW-class permanent magnet (PM) machines intended for aircraft propulsion. Two MW-class PM machine models with 12-phase configurations are developed, designed with strong symmetry to minimize the influence of circulating currents on AC copper losses. Leveraging detailed 3D winding models, the differences in end-winding length are quantified, enabling the estimation of corresponding inductance and resistance for each topology. These parameters are subsequently used to evaluate the copper losses. The results indicate that the total copper loss in the U-shaped hairpin topology is approximately 8% higher than that of the CHW configuration. The resulting thermal performance is assessed with temperature distributions analyzed in the stator core, slot windings, and end-windings under identical cooling conditions.