Eddy Current and Loss of Graded-Resistance No-Insulation Coils in HTS Synchronous Machines of Electrical Aircraft

Yutong Fu, Qingqing Yang, Guangyu Jiang, Yawei Wang, Wenbo Xue, Yue Zhao, Zhijian Jin

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


The No-insulation (NI) high temperature superconductor (HTS) machine is a promising propulsion technique for future large-scale electrical aircraft because of its high power density and enhanced thermal stability. However, in the machine environment, the ripple magnetic fields can induce significant eddy currents and losses on the NI coil. A grading turn-to-turn resistivity technique has been proposed to solve this problem, in which higher turn-to-turn resistivity is applied on the outermost turns of the NI coil, and lower turn-to-turn resistivity is kept on middle turns. The purpose of this research is to study the effects of grading turn-to-turn resistivity technique on the eddy current and loss of both single and multiple NI HTS coils exposed to ripple fields. To investigate the electromagnetic behavior and loss mechanism of NI HTS coils, a simulation model is proposed that couples the equivalent circuit model and finite element model. Results show that the grading turn-to-turn resistivity can effectively reduce the induced eddy current and lead to a uniform distribution of eddy current among turns of both single and multiple windings. It reduces magnetization loss in superconducting layers but increases the turn-to-turn loss on the radial contacts. These results are useful for the development of NI HTS machines with high thermal stability.
Original languageEnglish
Article number5201507
Pages (from-to)1-7
Number of pages7
JournalIEEE Transactions on Applied Superconductivity
Issue number5
Publication statusE-pub ahead of print - 20 Mar 2023


This work was supported in part by the Natural Science Foundation of Chongqing under Grant 2022NSCQ-MSX1512 and in part by the Natural Science Foundation of China under Grant 5217070020. Publisher Copyright: IEEE


  • electrical aircraft
  • no-insulation HTS coil
  • quench
  • ripple Fields
  • turn-to-turn resistivity

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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