ac loss analysis for superconducting generator armatures wound with subdivided Y-Ba-Cu-O coated tape

Advances in Y-Ba-Cu-O coated thin film tape may allow narrow filaments with very high current density on a thin metal alloy substrate which is separated from the superconductor by a dielectric buffer. These tapes will exhibit minimized ac loss by subdividing the Y-Ba-Cu-O layer with barriers which exhibit high electrical resistance. Assuming a fully penetrated magnetic field, low loss conductor concepts were incorporated into 1 MW armature designs for various configurations of Y-Ba-Cu-O conductors over the frequency range 50-1000 Hz. Low ac loss armature conductor designs are developed for megawatt class generators loss for both a 50-60 Hz utility application and a higher frequency aircraft application. Conductor design tradeoffs are discussed and ac loss minimization techniques compatible with realistic Y-Ba-Cu-O coated conductor processing are considered, The ac loss in Y-Ba-Cu-O armature windings of a synchronous alternator may for the first time permit practical, lightweight all-cryogenic generators which can deliver greater than or equal to megawatt at frequencies much greater than 50-60 Hz. (C) 2001 Published by Elsevier Science Ltd.