<p>Flat-wire windings are characterized by a high slot fill factor and enhanced thermal dissipation capability. Their application in permanent magnet synchronous motors (PMSMs) can further enhance efficiency and power density. However, the pronounced eddy-current effects associated with flat-wire windings constitute a critical limitation for high-speed and high-power operation. To address the high-frequency AC loss problem in hairpin windings, this study analyzes and calculates the eddy current losses in flat-wire windings. Building on this analysis and considering the specific characteristics of PMSMs, we propose a novel hybrid configuration combining variable cross-section windings (based on magnetic field distribution) and stranded windings. In this structure, each conductor adopts a radially graded, non-uniform cross-section optimized according to the local magnetic-field distribution within the stator slot. Furthermore, accounting for the impact of the conductor aspect ratio on motor parameters, the first four pole-pitch sections employ a sectioned winding design. Subsequently, using a 65&#xa0;kW PMSM designed for electric vehicle traction as a case study, we calculate the current distribution and AC losses within the windings under both rated-speed and high-speed operating conditions. Comparative analysis of losses across different winding configurations demonstrates that the proposed novel structure exhibits significantly lower AC losses than conventional hairpin windings, particularly in the medium-to-high operating frequency range.</p>