Efficiency Analysis for Inductive Power Transfer Using Segmented Parallel Line Feeder

SUMMARY Parallel line feeder (PLF) consisting of a two-wire transmission line operating in the MHz band has been proposed as a wide-coverage short-distance wireless charging. In the MHz band, a PLF of several meters su ff ers from standing wave e ff ect, resulting in fluctuation in power transfer e ffi ciency accordingly to the receiver’s position. This paper studies a modified version of the system, where the PLF is divided into individually compensated segments to mitigate the standing wave e ff ect. Modelling the PLF as a lossy transmission line, this paper theoretically shows that if the segments’ lengths are properly determined, it is able to improve and stabilize the e ffi ciency for all positions. Experimental results at 27.12 MHz confirm the theoretical analysis and show that a fairly high e ffi ciency of 70% can be achieved.