Analysis, Design and Optimization of a High-Speed Interior Permanent Magnet Rotor

This work presents the analysis, design and optimization of a high-speed interior permanent magnet (IPM) rotor. For the high-speed IPM rotor, mechanical stress which is caused by centrifugal force is the main problem. The permanent magnet (PM) arrangement and iron bridge shape have a significant influence on the stress of rotor core and electromagnetic performance. Firstly, based on the principle of IPM rotor stress generation, an analytical formula of mechanical stress on the IPM rotor is derived. Secondly, four different IPM rotor models with different PM arrangements are selected, and maximum mechanical stress and back electromotive force (EMF) are analyzed by the finite element method (FEM). Thirdly, in order to improve the mechanical and electromagnetic performance of high-speed interior permanent magnet synchronous machine (IPMSM), the sensitivity analysis, the response surface method (RSM), and the particle swarm optimization (PSO) are introduced to optimize the high-speed IPM rotor. Based on the initial model, an optimization design for minimum rotor stress and maximum back EMF is performed. Finally, the validity and superiority of the optimization design are confirmed by the FEM and prototype experiments.