Next Article in Journal
CCN-Based Inter-Vehicle Communication for Efficient Collection of Road and Traffic Information
Previous Article in Journal
Development and Validation of a LiDAR Scanner for 3D Evaluation of Soil Vegetal Coverage
Previous Article in Special Issue
Energy-Efficient Wireless Hopping Sensor Relocation Based on Prediction of Terrain Conditions
Open AccessLetter

Wireless Power Transfer under Wide Distance Variation Using Dual Impedance Frequency

Department of Electrical Engineering, Incheon National University, Incheon 22012, Korea
*
Author to whom correspondence should be addressed.
Electronics 2020, 9(1), 110; https://doi.org/10.3390/electronics9010110
Received: 22 November 2019 / Revised: 26 December 2019 / Accepted: 5 January 2020 / Published: 7 January 2020
(This article belongs to the Special Issue Wireless Power/Data Transfer, Energy Harvesting System Design)
A dual-impedance operation, where coil impedance is controlled by operating frequency selection, is proposed to maintain optimum reflected impedance across coupling variation. More specifically, this work focuses on how high coupling between coils presents excessively high reflected resistance to transmitter (Tx) inverters, degrading the efficiency and output power of the inverter. To overcome this problem, the proposed system is equipped with dual-impedance coil and selects high- or low-impedance coil based on the ability to operate both at 200 kHz and 6.78 MHz frequencies. The reactive impedances of 6.78 MHz coils are designed to be higher than that of 200 kHz coils. Since the reflected resistance is proportional to the coil impedances and coupling squared, at close distance with high coupling coefficient, 200 kHz coils with low coil impedances are activated to prevent an excessive rise in reflected resistance. On the other hand, at large distance spacing with low coupling coefficient, 6.78 MHz coils with high coil impedances are activated so that sufficient reflected resistance is obtained even under the small coupling. The proposed system’s advantages are the high efficiency and the elimination of bulky mechanical relay switches. Measured efficiencies are 88.6–50% across 10 coupling variations. View Full-Text
Keywords: inductive power; dual impedance; dual band; reflected resistance; frequency splitting inductive power; dual impedance; dual band; reflected resistance; frequency splitting
Show Figures

Figure 1

MDPI and ACS Style

Lee, W.; Ahn, D. Wireless Power Transfer under Wide Distance Variation Using Dual Impedance Frequency. Electronics 2020, 9, 110.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop