Performance comparison of 1X versus 4X HTS tapes toward the design a 10‐MW direct drive HTS generator for wind turbine applications

Abstract

AbstractWith current developments underway at the University of Houston, 4× high‐temperature superconducting (HTS) yttrium barium copper oxide (YBCO) tapes are expected to reach a fourfold critical current density improvement at 30 K and 3 T as part of an Advanced Research Projects Agency‐Energy (ARPA‐E)‐sponsored project. The impetus for this project is to develop and deploy cost‐effective direct drive HTS generators for large offshore wind turbine generators. The improved conductor performance of 4× tapes over 1× tapes is projected to allow for a significant reduction in the amount of HTS tapes required to generate the excitation field and, thus, lead to a reduction of the overall generator cost. It was, however, deduced from simulation results that conventional methods of rotor field enhancement using rotor iron makes 1× conductor competitive enough compared with 4× conductors; hence, commercially available YBCO tapes can provide all the energy density requirements to make wind turbines a competitive energy resource based on energy forecasts. This paper is a presentation of design and optimization work to find the best generator topology from the point of view of both machine design and electricity supply. The generators are numerically modeled and simulated using 1× and 4× YBCO HTS conductors on either or of both the rotor and stator side of the generators.