Design Study of 2-MW Fully Superconducting Synchronous Motors

This study designed various 2-MW fully superconducting motors with the recently developed REBa
₂
Cu
₃
O
_7-δ
(RE: Rare Earth, Y, Gd, Eu, REBCO) superconducting tapes to determine an optimum structure. The ac loss and critical current properties of the REBCO tapes were investigated and adopted in the design and analysis of the motor. The motors were designed by setting the operating temperature and the magnitude of magnetic field at the gap as parameters, and the properties of each motor were evaluated through numerical simulations with commercially available two-dimensional analysis software. Various factors, such as ac loss in the windings, efficiency, and the length of the required REBCO tapes, were evaluated, and the dependence of these factors on the operating temperature T, magnetic loading B
_g
, and diameter of motor D were analyzed. The ac loss induced in the armature windings could be reduced by our original technique, which involves scribing into a multifilamentary structure and special winding of the tapes. As a result, the motor could achieve an efficiency of 97.2% under optimum conditions, in which the REBCO tape is scribed into a 10-filament structure. Setting lower B
_g
and higher T is more favorable for enhancing efficiency, whereas the condition of lower B
_g
and T is more favorable for achieving compactness and lightness.