Parametric AC Loss Study on 7 MW Fully Superconducting Direct-Drive Wind Turbine Generators With Concentrated Stator Winding

Fully superconducting gearless wind generators with ReBCO windings and 7 MW power rating at 8.33 rpm are analysed by means of 2D finite element models in theH-A-formulation. A parametric design model is used for a systematic variation of the stator current loading for different operating temperatures and at fixed output power. More than 100 variants are analysed. The AC loss in the three-phase, concentrated stator winding is calculated. Pronounced minima of the high-temperature superconductor (HTS) AC loss are found under variation of the stator current loading. An exemplary generator design is derived, which features a 2.7 percentage points higher rated efficiency than a permanent magnet excited generator with copper stator winding.