Multidisciplinary Design Overview and Comparison for Two Case Studies of High Speed Permanent Magnet Machines

High-speed electrical machines have become more and more popular applications driven by electric vehicles and all-electric aircraft. Their design usually requires a high level of integration, including loss, thermal, cooling, and mechanical aspects. This article makes a comprehensive overview of the multidiscipline design method of high-speed permanent magnet (HSPM) machines. A 4-kW machine with the flexible rotor operating above the first bending critical speed is presented, and a 30-kW machine is also developed with consideration of the multidisciplinary design process for contrast. The constraint and the mechanism in the overview are investigated to clarify the influence of different design variables on the rotor structure and performance. Finally, two machines are fabricated and tested, and the values are compared with theoretical results.