Research on ac copper losses in permanent magnet electrical machines with hairpin windings for automotive applications

In this paper current displacement effects and subsequently ac copper losses in hairpin windings are analyzed in detail for the example of permanent magnet excited electrical machines. The increase of copper losses due to skin- and proximity effects is evaluated across the entire torque-speed map. Their impact on the drive cycle efficiency is discussed for the standardized Worldwide Light Vehicles Test Cycle (WLTC). Moreover, the influence of the rotating magnetic field generated by the rotor’s permanent magnets on the ac copper losses is studied.