Design Morphology for High-Speed Rotors in Electrical Machines Based on Analytical Models

The state-of-the-art for high-speed rotors in induction machines and permanent magnet synchronous machines is discussed. The rotors for permanent magnet synchronous machines are distinguished between rotors with surface permanent magnets and rotors with buried permanent magnets. For induction machines, the conventional laminated rotor is compared to solid rotor designs. Based on the equivalent ring method, analytical models to calculate mechanical stresses within the presented rotor topologies are developed. Thereby a morphological comparison of the rotor topologies with regard to achievable circumferential velocity is possible.