Reducing AC Joule Losses in Hairpin Windings of Electric Machines: Strategies for Minimizing Losses Due to Radial and Tangential Flux

Abstract

This paper presents a comprehensive analysis of conductor design strategies to reduce joule losses in hairpin windings of high-speed permanent magnet synchronous machines (PMSMs). With the increasing demand for high torque density, efficiency, and high-speed operation in electric vehicles and aircraft, minimizing these losses is crucial. Starting with a reference winding layout, various loss mechanisms due to radial and tangential flux components are investigated using finite element analysis (FEA) under both no-load and short-circuit conditions. Design variants including adjustments to conductor geometry, slot opening shapes, layer-specific conductor height tuning and segmented conductor designs with overhang twisting are explored. The findings are relevant for improving the performance and manufacturability of electric machines, with additive manufacturing offering new design opportunities for enhanced efficiency and lower losses.