Impact of Soft Magnetic Material on Electromagnetic Force and Vibration of Permanent Magnet Electrical Machines

Electromagnetic vibration is excited by the radial electromagnetic force generated by the air-gap magnetic field acting on the stator core. In this paper, an analysis and reduction of electromagnetic force in high-speed permanent magnet electrical machines with different stator cores are investigated. A fast and accurate calculation method of air gap flux density and radial force density distribution are derived. The radial force density including amplitude, frequency, and order is obtained by a two-dimension fast Fourier transform. Then, the effect of the different PM segmentation on radial force is summarized.