Calculation and Analysis of Winding Copper Loss in High Speed Permanent Magnet Synchronous Motors for Vehicles

Flat wire windings can help increase the power density of motors. However, under high-speed operating conditions, their AC losses are relatively severe. Using hybrid conductors in flat wire windings can effectively reduce AC losses. But there is still a lack of research on the copper losses of such windings. This paper first designs hybrid winding schemes using different combinations of flat wires and litz wires for two-layer windings at the slot opening based on hairpin winding. It then analyzes the influence of different wire types on the slot fill factor of the motor. Then, it establishes copper loss analysis models for different wire type windings, studies the AC and DC copper losses of motors with different wire type windings, and summarizes the variation laws of copper losses in windings with different wire types. Finally, it compares the loss and efficiency of different wire type windings under typical operating conditions in vehicle high-speed permanent magnet motors, and evaluates the applicability of these winding types.