Lightweight Design of Tens-MW Fully-Superconducting Wind Turbine Generators With High-Performance REBa2Cu3Oy Wires

15 MW-class Direct-drive fully-superconducting generators for offshore floating wind turbine generators were conceptually designed. High-performance EuBa
₂
Cu
₃
Oy (EuBCO) superconducting wires with a large in-field critical current were employed, which can reduce the wire length of the generators. The design study showed good electromagnetic properties: high efficiency of 96.5%, and a low synchronous reactance of 0.4 p.u. The total weight of the superconducting generators including support structures was assumed as ~98 tons, which is much lighter than partially-superconducting generators and conventional generators. Furthermore, our superconducting generator satisfied the cost requirement due to employing high-performance EuBCO wires and reducing field winding length by a unique casing structure. In conclusion, the fully-superconducting generators have a great advantage, especially for a tens-MW wind turbine system.