Design Approach of Hairpin Winding Motor with High Parallel Path Numbers

This work aims to study the design principle of hairpin winding topology with high parallel path numbers per phase. Hairpin winding offers the advantages of high slot fill factor and automated winding process, which promote its application in the traction motors. As the motor power and speed continuously going up, the large size of the conductors are prone to proximity loss and eddy current loss due to the non-uniform current distribution, and the series connected turn numbers per phase are limited by the DC voltage. Therefore, this work is to investigate the hairpin winding design approach with high parallel path numbers per phase to meet the voltage and current constraints, and to keep the front and back connections having equal coil length as much as possible, respectively. The effect of parallel path numbers on the AC loss will be analyzed using finite-element analysis. The impact of asymmetric conductor configurations has also been evaluated.