FINE-FILAMENT MAGNESIUM DIBORIDE SUPERCONDUCTOR WIRE FOR TURBOELECTRIC PROPULSION SYSTEMS

The availability of low AC loss magnesium diboride (MgB2) superconducting wires enables much lighter weight superconducting stator coils than with any other metal or ceramic superconductor. This, together with Hyper Tech's capability to fabricate long piece-length (potentially 60 km) wires, in turn enables lighter superconducting motors/generators, essential components in the turboelectric aircraft propulsion system envisioned in next generation Air Vehicle Technologies. To that end, this proposed SBIR Phase I program focuses on developing MgB2 multifilament wires with the smallest practical filament size achievable (10 ��m or less) as a means to reducing AC losses due to hysteresis, eddy current, and coupling losses. Two recent advancements at Hyper Tech greatly increase the odds of success: 1) The emergence of a novel MgB2 wire manufacturing method that incorporates a magnesium-infiltration process (precursor materials are magnesium wire and powder boron) that has produced a 10-fold enhancement in critical current density over that of present state-of-the-art wires made by the conventional method involving magnesium-boron powder mixtures, and 2) Improved capability in wire drawing to fabricate fine multifilament strands.

Besides stator coils, magnesium diboride superconductors can benefit NASA applications for many applications where light weight power components that are required for generators, motors, transformers, inductors, power conditioning equipment and ADR coils. Other magnet applications that magnesium diboride wires can be considered for are magnetic bearings, actuators, MHD magnets, propulsion engines, magnetic shielding in space, and magnetic launch devices.

Manufacturers of large electrical systems desire to increase the efficiency, and decrease the size of their systems in order to reduce costs. Presently major manufacturers of MRIs, transformers, motors, generators, and fault current limiters are pursuing MgB2 superconductor wires to achieve these objectives. More recently there has been a growing global market for a new class of large machines requiring high power density (from 4 to 20 MW) including wind and wave turbine generators, aircraft turbo-generators, offshore oil platform motors, marine propulsion and generation systems and portable emergency power systems.