Ultra-High-Field, High-Efficiency Superconducting Machines for Offshore Wind Turbines

Thanatheepan Balachandran, Andy Yoon, Dongsu Lee, Jianqiao Xiao, Kiruba S. Haran

Research output: Contribution to journalArticlepeer-review


Offshore wind turbines are the key enabling technology to increase the green energy penetration in the electricity market. Increasing the power generation per tower and reducing the levelized cost of energy are the two significant problems faced by wind turbine manufacturers. Traditional turbine manufacturers use rare-earth permanent magnets (PMs) to increase the air-gap flux density and maximize the machine outer diameter (OD) to increase the torque output. Since the air-gap flux density achievable with available PM is limited, increasing the power output of a traditional generator invariably leads to a significant increase in the volume and mass on top of the turbine tower and associated manufacturing, transportation, and installation costs. Superconducting (SC) wind turbine generators offer 5 to 10 times the air-gap flux density of a PM generator, and a corresponding increase in specific power and power density. Previous MW scale SC wind turbines designs used heavy back iron in the design, iron saturation limits the achievable air-gap flux density in the designs and resulted in bulky generators and moderate efficiency. In this article, a hybrid design approach is proposed to reach an ultrahigh field (5 to 10 times of PM air-gap flux density) and high efficiency (>98%) SC wind turbine for offshore wind turbine. An additional stray field limitation is introduced for safety concerns and shielding techniques are explored. Electromagnetic, mechanical, and cooling designs are provided to support the feasibility of proposed SC wind turbines. A nacelle integration inside a commercially available 6 MW wind turbine is shown to demonstrate the size comparison of the proposed generator.

Original languageEnglish (US)
JournalIEEE Transactions on Magnetics
Issue number2
StatePublished - Feb 1 2022


  • Generators
  • Heating systems
  • High efficiency
  • high temperature superconductor
  • High-temperature superconductors
  • Iron
  • low temperature superconductor
  • superconducting
  • Superconducting coils
  • Topology
  • ultra high field
  • Wind turbines
  • wind turbines
  • ultrahigh field
  • superconducting (SC)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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