Analysis of low harmonic windings for high-speed permanent magnet machines

When the high-speed permanent magnet machine is operating, the power supply frequency and the core frequency can reach thousands of Hertz. The rotor loss caused by high speed and high frequency, especially the temperature rise, which poses a severe challenge to the reliable operation of high-speed machine systems. Therefore, it is necessary to weaken the interaction between the MMF harmonics and the rotor magnetic field. To this end, this paper uses multi-layer winding to optimize the MMF of the Stator to minimize the negative effects caused by the MMF harmonics. Comprehensive simulations demonstrate that the appropriate number of winding layers can significantly weaken the harmonics of the other orders except for the fundamental wave, reduce the torque ripple and minimize the rotor loss (especially eddy-current loss) to improve the performance of high-speed permanent magnet machine.