Researchers Boost Wireless Power Transfer With Magnetic Field Enhancement

For Immediate Release

David Ricketts david.ricketts@ncsu.edu 919.513.7361

Matt Shipman matt_shipman@ncsu.edu 919.515.6386.

来自北卡罗来纳州立大学和研究Carnegie Mellon University shows that passing wireless power transfer through a magnetic resonance field enhancer (MRFE) – which can be as simple as a copper loop – can boost the transfer efficiency by at least 100 percent as compared to transferring through air alone. MRFE use could potentially boost transfer efficiency by as much as 5,000 percent in some systems, experts say.

Wireless power transfer works by having a transmitter coil generate a magnetic field; a receiver coil then draws energy from that magnetic field. One of the major roadblocks for development of marketable wireless power transfer technologies is achieving high efficiency.

“Our experimental results show double the efficiency using the MRFE in comparison to air alone,” says David Ricketts, an associate professor of electrical and computer engineering at NC State and corresponding author of a paper describing the work.

增强无线功率效率是许多研究组的主要目标。提高效率的领先候选人之一是一种称为超材料的技术。“我们使用无线电力系统的计算机型号进行了全面的分析，发现MRFE最终比使用超材料的使用量比仅使用超级材料的50倍，而不是通过单独传输空气的50倍，”Ricketts说。

By placing the MRFE between the transmitter and the receiver (without touching either) as an intermediate material, the researchers were able to significantly enhance the magnetic field, increasing its efficiency.

“We realized that any enhancement needs to not only increase the magnetic field the receiver ‘sees,’ but also not siphon off any of the power being put out by the transmitter,” Ricketts says. “The MRFE amplifies the magnetic field while removing very little power from the system.”

The researchers conducted an experiment that transmitted power through air alone, through a metamaterial, and through an MRFE made of the same quality material as the metamaterial. The MRFE significantly outperformed both of the others. In addition, the MRFE is less than one-tenth the volume of metamaterial enhancers.

“This could help advance efforts to develop wireless power transfer technologies for use with electric vehicles, in buildings, or in any other application where enhanced efficiency or greater distances are important considerations,” Ricketts says.

A pre-proof draft of the paper, “具有超材料和磁共振耦合器的无线电源的磁场增强,” is published online in the journalIEEE Antennas and Wireless Propagation Letters. Lead author of the paper is Matthew J. Chabalko, who worked on the project as a postdoctoral researcher at Carnegie Mellon and now works at Disney Research. Jordan Besnoff, a postdoctoral researcher at NC State, is a co-author of the paper.

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Note to Editors:The study abstract follows.

“具有超材料和磁共振耦合器的无线电源中的磁场增强”

Authors：Matthew J. Chabalko，卡内基梅隆大学，迪士尼研究;北卡罗来纳州立大学乔丹贝诺夫和大卫·里克特斯

Published: pre-proof draft online July 1 inIEEE Antennas and Wireless Propagation Letters

DOI: 10.1109/LAWP.2015.2452216

Abstract:We report on the magnetic field and coupling enhancement for increased wireless power transfer efficiency using intermediate materials. We examine the physical mechanisms for enhancement using a metamaterial (MM) and magnetic resonant field enhancement (MR-FE) and present an analytical and simulation analysis as well as an experimental study of these enhancement mechanisms. While both increase the mutual coupling, the loss of the contrasting enhancement mechanisms significantly impacts WPT efficiency enhancement. Our analysis shows that the MR-FE approach can have up to a 4 times higher efficiency over the MM approach due to the lower loss of its field enhancement mechanism.