Calculation and Analysis of Interturn Voltage Stress in Hairpin Windings for EV Traction Machines Considering the End-Winding Parasitic Effect

With the increasing adoption of silicon-carbide inverters and hairpin winding (HW) traction machines, nonuniform interturn voltage stress (ITVS) under high-frequency, high-pulse-width modulation excitation has become a critical issue. This article proposes a high-frequency equivalent-circuit of HW considering end-winding parasitic effect. First, the end-winding parasitic parameters are extracted using a 3-D model, while the frequency-dependent winding parameters are obtained from a 2-D finite element model and integrated into a coupled field-circuit transient simulation to predict ITVS distributions. Then, the influence of end-winding geometry, particularly the gap between adjacent inclined edges, on the ITVS is analyzed. Finally, the experimental validation demonstrates high agreement between simulation and measurement, with a peak deviation of 1.63%, supporting the predictive capability of the proposed model and method. The proposed model of ITVS and validation framework provides practical guidance for end-winding layout optimization and insulation-oriented design of HW machines of electric vehicle.