Design, development and testing of a high-speed axial-flux permanent-magnet machine

This paper gives an overview of the design, manufacturing and testing of a high speed (16000 rpm and 30 kW) AFPM synchronous machine, which is mounted inside, and as an integral part of, a flywheel; this system will subsequently be used for transient energy storage and ICE operating point optimization in an HEV. The paper focuses on the major design issues, particularly with regard to the high rotational speed, and investigates the loss mechanisms which are apparent therein, e.g. iron losses, rotor losses, and friction losses. The paper describes the high-speed testing facility and includes measured results; these are compared to calculated values.