Design of a Cryogenic Cooling Concept for a Permanent Magnet Synchronous Machine

All electric aircraft demand for new electrical drive train topologies. Following the application of a previously presented cryogenic cooled permanent magnet synchronous machine, this paper investigates a new concept of hydrogen cooling. Giving a brief overview of the initial machine design, a direct end winding cooling will be shown, exploiting the beneficial behaviour of thermal conductivity at low temperatures. As an additional step, an auxiliary closed-loop helium cooling will be presented. Besides the outline of the cooling concept, the design procedure will be presented from scratch, starting with analytical approximations culminating in FEA. In the end a final design solution will be discussed, showing that the initial requirements can be reached with the proposed design concept.