Wireless power transfer using relay resonators

This paper presents an advanced design configuration of a wireless power transfer system using overlapping relay coil techniques for free loading position. The work undertaken investigates the tuning position of prototype relay coils in a horizontal configuration in order to evaluate power transfer efficiency versus increasing operating distance between the transmitter and receiver coils. A prototype relay coil system was evaluated to determine the optimum distance between the transmitter and receiver. Finite element magnetic (FEM) simulation was used to appraise the magnetic field distribution and power transfer efficiency with respect to a strongly coupled magnetic resonance condition. Experimental and simulation results analysis suggest that the proposed design could achieve 85% to 90% efficiency within a 4 cm operational distance. Finally, the experimental results were analyzed and compared with the simulation results.