Conjugate Image Theory Applied on Capacitive Wireless Power Transfer

Ben Minnaert,Nobby Stevens

doi:10.3390/en10010046

Abstract

Wireless power transfer using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications. However, for certain applications, capacitive wireless power transfer using electric coupling might be preferable. In order to obtain a maximum power transfer efficiency, an optimal compensation network must be designed at the input and output ports of the capacitive wireless link. In this work, the conjugate image theory is applied to determine this optimal network as a function of the characteristics of the capacitive wireless link, as well for the series as for the parallel topology. The results are compared with the inductive power transfer system. Introduction of a new concept, the coupling function, enables the description of the compensation network of both an inductive and a capacitive system in two elegant equations, valid for the series and the parallel topology. This approach allows better understanding of the fundamentals of the wireless power transfer link, necessary for the design of an efficient system.

Highlights

Different methods exist to transfer energy wirelessly
Wireless power transfer (WPT) using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications, from charging smartphones to electric vehicles [3]
Since r1 and r2 are small, we find for the wireless link itself an almost ideal power transfer efficiency of ηmax = 99.9%

Summary

Introduction

Different methods exist to transfer energy wirelessly. One could use electromagnetic waves such as light or microwave radiation [1], or even pressure or sound waves to transfer energy from a source to a load [2]. We will focus on transferring energy through quasi-static fields. Wireless power transfer (WPT) using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications, from charging smartphones to electric vehicles [3]. The principle of inductive power transfer (IPT) is based on the generation of a time-varying magnetic field by an alternating current in an inductor. Another inductor captures the energy within this magnetic field for the generation of current

Methods

Discussion

Conclusion