High Slot Fill Aluminum Distributed Winding for High-Speed and High Power Density Electric Machines

This paper proposes a novel aluminum distributed winding in high-speed and high power density electric machines for automotive applications. The maximum rotational speed and the power density are 50,000 min and 10 kW/kg, respectively. The maximum current frequency is 3.3 kHz when the number of poles is eight; and therefore, it has serious problem of the winding AC loss. The high slot fill aluminum winding is a solution because it can reduce both DC and AC losses. In this paper, the cross-sectional shapes of the aluminum distributed winding are proposed to reduce the winding loss at high-speed region. In 2DFEM analysis, it is shown that winding losses can be reduced by 61.2% at 50,000 r/min. In addition, the prototype motorette is fabricated and tested.