Bi2212 Superconductors for High-Power Density Motors for Aero Propulsion

Future hybrid aircraft, such as NASArsquo;s N3-X plan, will require all-superconducting electric motors and generators in order to achieve power densities in excess of 10 kW/kg with strong drivers for it to be an all superconducting design that operates at 40 K or greater. nbsp; Unlike the DC rotor, the stator must operate in AC mode, for example, from 0-0.5 T at gt; 100 Hz, making it impossible to use high temperature superconducting (HTS) tapes due to their high losses in AC fields, requiring instead fine wires with loss reducing features like axial twist, higher inter-filament resistances, and cable-ability into a transposed form.nbsp;nbsp;Our innovation consists of an all-HTS, lightweight high power motor, in which the stator coils are wound with our unique low loss, transposed cables, that are comprised of our novel, low loss, small diameter HTS 2212 wires ndash; not wide tapes, where these wires are equipped with all required loss reducing features while operating at gt;40 K with a current density that provides gt; 10 kW/kg power as specified in NASA Subtopic A1.07. Based on the Phase 1 results, an optimized, practical 2212-based wire and cable will be developed for fabricating a stator that meets low loss, current density and gt; 40 K operating temperatures targets, with coils produced and tested to validate progress. nbsp; As the first step, loss reducing features and current densities of best mode wire designs identified in Phase 1 will be developed, along capability for longer length production. A low loss cable design will then be developed with loss testing validating that both wire and cable meet the required loss levels - a feat that has been out of reach with HTS until this program.nbsp; Coil building techniques will then be advanced by fabricating and testing racetrack forms and applying this know how to build and test a demo coil with all the features required to provide gt;40 K superconducting stator operability in the specified high power density.nbsp;nbsp;