Trade-offs in design of high-speed permanent magnet generators for gas-turbine-based micro-CHP systems

Micro CHP (combined heat and power) systems based on gas turbines represent a typical application which widely exploits high-speed permanent magnet machines. As an energy application which implies electromechanical conversion at high speeds, it sets high requirements with respect to power density and efficiency. In order to fulfill these requirements, high energy magnet materials have to be used. Significant drawbacks of high energy magnets are their thermal and structural vulnerabilities. This paper describes initial choices and trade-offs with the machine design in order to satisfy requirements for high power density and efficiency; at the same time such a design must ensure proper operating conditions for magnet materials from thermal and structural point of view.