High Speed Superconducting Machine for Turbo-Generator Applications

Compact, lightweight, high-efficiency generators capable of direct coupling to turbo-generators are needed, in the multi megawatt class. Alternating current (AC) homopolar machines are a compelling choice for these applications as they enable relatively high rotational speeds that permit direct coupling to the power turbine. Here we present design concepts for a high-speed homopolar generator featuring dual stationary superconducting field coils, one at each end of the machine. Magnetic flux is more concentrated along the active length, reducing the amount of iron required and improving power density. Furthermore, since the field coils are not trapped at the centre of the machine, they can be easily accessed for servicing or replacement.