Quantitative design and analysis of relay resonators in wireless power transfer system

Xiu Zhang, Siu Lau Ho, Weinong Fu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

89 Citations (Scopus)


Wireless power transfer systems are finding increasing applications which can enhance the living standard of the general public. Typical examples are wireless charging of mobile phone batteries and car batteries. Thanks to the advent of power electronics in the past few decades, some wireless charging systems are now emerging in the commercial sector. However, the transfer efficiency and transfer distance of these chargers are limiting the technology to a few specific applications only. In order to increase the transfer distance, some researchers have successfully proposed to use relay coils to improve their wireless power transfer efficiency. In this paper, the role of relay resonator is examined critically. The reported findings indicate that it is not always desirable to have relay coils in wireless charger as the relay resonator may increase, or sometimes reduce, the overall power transfer efficiency. The findings also reveal that there is an optimal position for the designer to locate the relay resonator to maximize the power transfer efficiency.
Original languageEnglish
Article number6333041
Pages (from-to)4026-4029
Number of pages4
JournalIEEE Transactions on Magnetics
Issue number11
Publication statusPublished - 29 Oct 2012


  • Equivalent circuit
  • Optimal position
  • Relay resonator
  • Wireless power transfer

ASJC Scopus subject areas

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


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