Cost-Effective Winding Strategy and Experimental Validation of a Real-Scale HTS Field Coil for 10 MW Class Wind Turbine Generators

In this study, real-scale high-temperature superconducting (HTS) field coils for a 10 MW class rotating machine were designed, fabricated, and experimentally evaluated. The aim was to propose a cost-effective winding strategy by combining two types of HTS wires with different angular dependencies of critical current. The 3D FEM simulations were performed to determine the coil layout by considering the magnetic field magnitude and incidence angle. Based on this design, two HTS field coils were fabricated, one wound with two different types of wire and the other with a single wire type. For application to an actual HTS generator, the coil was equipped with an iron core to evaluate its influence on critical current and magnetic field distribution. Experimental results at 77 K showed that the coil combined with two types of HTS wire achieved 112 A without the core and 105 A with the core, while the single-wire coil reached 101 A and 93 A, respectively. The measured results showed good agreement with the simulations, with deviations within 3.7% for the combined-wire coil and 1.9% for the coil equipped with the iron core. These findings indicate that the proposed winding method can maintain high performance while lowering material cost, providing useful guidelines for the design of large-scale HTS rotating machines.