Broad Range Impedance Matching using Magnetic Resonance WPT Parameter Extraction with Coil Placement

This paper presents a method of optimizing the impedance matching by changing the wireless power transfer characteristics according to the placement and relative positions of the resonance coils by equivalent circuit analysis. For the case of 3-coils configuration, the transmission characteristics deteriorate with the change of the coil position. When 4-coils are used, the efficiency is maintained more than 80% over certain range regardless of the coil position with the proposed impedance matching.