Evaluation of AC Copper Loss in High-Speed & High-Power Electric Machines

This paper reports on an electric machine used as a component in an electric turbocharger for an air supply system. Enhancing the specific power (kW/kg) and power density (kW/L) is crucial in this application scenario. To address this, we propose a multi-pole electric machine capable of achieving high speeds (tens of thousands of RPM) and high outputs (70 kW class). Furthermore, in this electric machine, the impact of the proximity effect is significant. Hence, we analytically evaluated the AC copper loss and took measurements via back-to-back testing using a prototype. The results confirmed the validity of our analytical method.