Effect of wireless power link load resistance on the efficiency of the energy transfer

With the proper impedance matching system, a high efficiency can be acquired in wireless power transfer applications. Variations of the coupling coefficient factor could deviate, however, the impedance matching system from the designed considerations. In this paper, the transmitter reflected impedance from the receiver side is analyzed to avoid divergence of the impedance matching network considering a wide air gap range between transmitter and receiver sides. A 2 kW contactless system is designed to investigate an optimum impedance requirement by testing several displacement gaps between coils. Experimental results are demonstrated to reveal a relation between the efficiency and the reflected impedance.