Analysis of Mid-range Wireless Power Transfer Circuits Based on Reactance Function and Image Impedance

摘要

This paper proposes a novel method to analyze the mid-range wireless power transfer circuits comprised of square coils and capacitors and maximize overall efficiency. The method is based on the equivalent circuit model derived from the reactance function and image impedance. The mid-range circuits are promising as an efficient wireless power transfer method using near field electromagnetic waves. However, no simple design and the analysis methods are available for wireless power transfer. This paper assumes both transmitter and receiver antennas are identical and electrically small. It analyzes the resonance frequencies of the even and odd modes, which are used to model the equivalent circuit describing the actual wireless power transfer circuits. This paper also analyzes the transfer efficiency using the equation of the equivalent circuit, simulation software based on the moment method and an experiment. It clarifies that the analytical values derived by the proposed method and the simulation results mostly agree with the measured values. As a result, the mid-range wireless power transfer circuits designed using the proposed analysis method achieve high efficiency.