AC loss of flat copper winding in high speed permanent magnet machine
ZHANG Bing yi, LIU Yun fei, FENG Gui hong, LI Qiao shan
（School of Electrical Engineering, Shenyang University of Technology, Shenyang 110870, China）

Abstract: Aiming at current in flat copper winding of high voltage high speed permanent magnet machines is of high frequency, which will produce the skin and proximity effects. In order to solve the problem of excessive eddy copper loss, influence factors of AC loss of flat cooper winding under high frequence were analyzed. According to the real size of flat copper, model of flat copper was built and 2D finite element method was employed to study the effects of rated frequency, carrier ratio, the height of the slot opening, the position and size of the conductor and the number of strands, and conclude the optimum ratio of width to thickness at different frequencies. The results indicate that the AC loss of flat copper winding can be significantly reduced by reasonably choosing the height of the slot opening, the size of the flat copper winding and the number of strands.

Key words: high speed permanent magnet machine; flat copper; AC copper loss; skin effect; proximity effect