Effect of Multi-Size Magnetic Powder Gradation on Magnetic Properties of Novel Composite Magnetic Materials for HSPMSM

The ordinary high-speed permanent magnet synchronous machines (HSPMSMs) have the problems of high rotor temperature rise. In order to solve these problems, a novel composite rotor HSPMSM (NCR-HSPMSM) is proposed in this article. The novel composite rotor includes a shaft, sintered permanent magnet, novel composite magnetic materials (NCMMs), and carbon fiber sleeve. The NCMMs are composed of magnetic powder, epoxy, and carbon fiber. The rotor eddy current loss is caused by high-frequency harmonics. Utilizing the low conductivity characteristics of NCMMs, the rotor eddy current loss can be effectively reduced. In addition, the magnetic properties of NCMMs are improved by multisize magnetic powder gradation. The proposed sandwich packing model of the novel magnetic materials is used to determine the minimum magnetic powder size ratio. Also, the effect of multisize magnetic powder gradation on magnetic properties of NCMMs is analyzed by particle flow code (PFC) simulation software, and the electromagnetic analysis of NCR-HSPMSM is carried out by the finite-element method (FEM). Finally, the accuracy of the packing model is verified by the experimental results.