A Dynamically Adaptable Impedance-Matching System for Midrange Wireless Power Transfer with Misalignment

Energies

Thuc Phi Duong²  Jong-Wook Lee¹ 

[1] Department of Electronics and Radio Engineering, Kyung Hee University, 1 Sochen, Giheung, Yongin, Gyeonggi 446-701, Korea; E-Mail

关键词: wireless power transmission;    resonant coupling;    impedance match;    dynamic adaptation;    efficiency;    misalignment;   

DOI  :  10.3390/en8087593

来源: mdpi

【 摘 要 】

To enable the geometrical freedom envisioned for wireless power transfer (WPT), fast dynamic adaptation to unpredictable changes in receiver position is needed. In this paper, we propose an adaptive impedance-searching system that achieves good impedance matching quickly. For fast and robust operation, the proposed method consists of three steps: system calibration, coarse search, and fine search. The proposed WPT system is characterized using distance variation and lateral and angular misalignment between coils. The measured results indicate that the proposed method significantly reduces searching time from a few minutes to approximately one second. Furthermore, the proposed system achieves impedance matching with good accuracy. The robust impedance-searching capability of the proposed system significantly improves power transfer efficiency. At 6.78 MHz, we achieve a maximum efficiency of 89.7% and a high efficiency of >80% up to a distance of 50 cm. When the center-to-center misalignment is 35 cm, the efficiency is improved from 48.4% to 74.1% with the proposed method. At a distance of 40 cm, the efficiency is higher than 74% for up to 60° of angular rotation. These results agree well with the simulated results obtained using a lumped-element circuit model.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.