ac Loss analysis for superconducting generator armatures wound with subdivided Y–Ba–Cu–O coated tape Original Research Article

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 ⩾ megawatt at frequencies much greater than 50–60 Hz.