Rigorous Network and Full-Wave Electromagnetic Modeling of Wireless Power Transfer Links

Abstract

The proposed approach makes use of full-wave electromagnetic modeling of wireless power transfer links in order to derive the network characterization, e.g., in terms of scattering or impedance matrix. Once the latter is obtained, we show that network theory provides the appropriate matching impedances for achieving either maximum efficiency, maximum power on the load, or conjugate matching. The proposed approach also permits to derive closed-form matching networks and expressions for power and efficiency. An example of full-wave numerical electromagnetic modeling of a wireless power transfer link is presented. The selected example, which is similar to the experiment published by Kurs et al., shows the importance of selecting the appropriate source/load impedance for obtaining significative results.

Conjugate Image Theory Applied on Capacitive Wireless Power Transfer

“…For any two-port network, these conditions are fulfilled for the following values of Z c1 = R c1 + jX c1 and Z c2 = R c2 + jX c2 [20,21]: …”

“…We want to stress that maximizing the efficiency of the power transfer does not correspond with maximizing the amount of transferred power to the load [21]. It can depend on the application whether the maximum efficiency or maximum power transfer solution is preferable.…”

Europe and the Future for WPT : European Contributions to Wireless Power Transfer Technology

“…In [48], a MRWPT system consisting of electrically and magnetically coupled spiral resonators and loop inductances was presented. In [48] and [49], the experiment reported in [50] has been reproduced by using a full-wave simulation. An approach considering the WPT link as a two-port network has been used.…”

“…An approach considering the WPT link as a two-port network has been used. In [49], a theoretical investigation has been performed in order to find, for a given WPT link, the load values that maximize either efficiency or the power on the load. In [51], a unified approach has been proposed for energy harvesting and WPT.…”

“…Near field WPT can be operated either at a fixed frequency, as considered in [49] (and in this case the optimal load value is dependent on the coupling) or with an agile frequency. In fact, when the coupling is changed, by appropriately changing the operating frequency, we can obtain higher power values on the load.…”