A Wireless Power Transfer System with Uniformly High Transfer Efficiency for Free Arrangement of the Receiver in a Wide Area

This paper presents the system of wireless power transfer (WPT) in a planar structure with various ways to increase both average value and uniformity in the efficiency of the proposed system. The horizontal flux approach is selected to implement the proposed system, taking advantage of optimization, compared to the system with the vertical flux approach. To overcome the limitation of the approach and enhance the performance, the following three methods are introduced. The permeability of the transmission medium, which is related to the transfer efficiency, is increased by using ferrite. Also, winding multiple transmitter coils is presented to improve uniformity. Finally, adjusting the structure of the transmitter coils raises the intensity of the net magnetic field. By a combination of these methods, average efficiency is observed as 81.3% with low standard deviation, indicating the system has uniformly high transfer efficiency all over the plate. Consequently, the proposed system demonstrates the feasibility of the WPT system in which the receiver can be located freely.