Identification and modeling method of wireless power transfer system in conductive medium using Z-parameters

Abstract

Recently, as the environment of applications applying wireless power transfer technology is diversified, many researches are being conducted in medium other than air, such as water and the human body. However, the inductive wireless power trasnfer using a magnetic field causes eddy current loss in a medium with electrical conductivity. The eddy current loss causes a change in impedance of the wireless power transfer system and a decrease in power transfer efficiency. Therefore, there is a need for a system analysis method taking this into account. This research proposes an accurate modeling method of wireless power transfer system reflecting the effect of eddy current loss occurring in a conductive medium using Z-parameters. And using the proposed model, we efficiently analyze the wireless power transfer system in a conductive medium through a simple circuit theory. The proposed method was verified and validated through mathematical calculations, electromagnetic simulations, and measurements. This research is expected to be utilized for analysis and design of wireless power transfer system in conductive medium.