Open AccessStudy on Two‐Coil and Four‐Coil Wireless Power Transfer Systems Using Z‐Parameter Approach
Author(s) -
Seo DongWook,
Lee JaeHo,
Lee Hyung Soo
Publication year - 2016
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.16.0115.0692
Subject(s) - wireless power transfer , electromagnetic coil , impedance matching , coupling (piping) , matching (statistics) , electronic engineering , range (aeronautics) , electrical impedance , power (physics) , maximum power transfer theorem , wireless , engineering , topology (electrical circuits) , electrical engineering , computer science , physics , mathematics , telecommunications , mechanical engineering , quantum mechanics , statistics , aerospace engineering
A wireless power transfer (WPT) system is usually classified as being of either a two‐coil or four‐coil type. It is known that two‐coil WPT systems are suitable for short‐range transmissions, whereas four‐coil WPT systems are suitable for mid‐range transmissions. However, this paper reveals that the two aforementioned types of WPT system are alike in terms of their performance and characteristics, differing only when it comes to their matching‐network configurations. In this paper, we first find the optimum load and source conditions using Z‐parameters. Then, we estimate the maximum power transfer efficiency under the optimum load and source conditions, and we describe how to configure the matching networks pertaining to both types of WPT system for the given optimum load and source conditions. The two types of WPT system show the same performance with respect to the coupling coefficient and load impedance. Further, they also demonstrate an identical performance in the two cases considered in this paper, that is, a strong‐coupled case and a weak‐coupled case.