Development of a High-Speed Electric Rotating Machine

High-speed electric rotating machines enhance power density and eliminate gearboxes in waste heat recovery microturbines, but conventional designs face high manufacturing costs and complex cooling requirements. This study presents the development, experimental validation, and comparative analysis of high-speed configurations. Initially, a lower-speed induction machine prototype operating at 13,000 rpm was built using standardized components to experimentally validate numerical loss models. Experimental testing of the initial prototype confirmed a total loss of 7.89 kW, closely matching the simulated 7.75 kW. Leveraging these findings, two next-generation topologies of decreased size, an induction machine and a surface permanent magnet machine, were designed and evaluated using finite element method and conjugate heat transfer simulations under sinusoidal and pulse-width modulation excitations. At a 14,000 rpm operational point, the surface permanent magnet prototype outperformed the induction machine configuration, ensuring the lower temperatures of the permanent magnet machine and achieving 63.2 kW of mechanical power and 96.21% efficiency compared to the induction machine's 52.4 kW and 94.64%.This paper builds upon the microturbine generator project introduced at the ICPGEEC 2025 conference, by presenting lighter, higher-speed machine designs.