Multiphysics Thermo-Structural Design of the Rotor in High-Speed Permanent Magnet Machines for Aerospace Propulsion Applications

High temperatures, thermal and mechanical stresses, rotor imbalances in high-speed Surface Permanent Magnet Synchronous machines (SPMSM) often dictates the maximum power output of the machine. Hence, a trade-off should be made between the cooling design, and machine structure stiffness, and the power rating. This work discusses the modelling and design process of the high-speed machine rotor by means of thermo-structural and modal analyses to minimize the trade-offs between the structural and thermal designs. The study discusses the design and modeling of SPMSM machine rotor thermally and structurally to achieve the highest power output of the machine while targeting rotor weight reduction. The design of the rotor shows safe operating temperatures and stress levels at the machine rated speed and power output as a result of the minimized and well-distributed thermal and mechanical stresses. A power density of 7.1 kW/kg is achieved by designing the machine within safe operating limits without using excessive safety margins.