Reconfigurable Resonant Topology Linking Two-, Three-, and Four-Coil Modes for WPT With Large Coupling Range and Fixed Frequency

In wireless power transfer (WPT) applications, it is usually desired to transfer full power from the transmitter to the receiver in a position range as large as possible. However, the full-power operation range of a WPT system is typically designed for a small position range. This article proposes a reconfigurable resonant topology adopting the splitting coil structure in both the primary and secondary sides. The proposed reconfigurable resonant topology can output high power when the air gap varies in a wide range. Simulation and experimental results are provided to demonstrate that the proposed reconfigurable resonant topology can output full power in a large coupling range without significantly increasing the VA rating of the system. The measured dc–dc efficiency of the 3.3-kW prototype in an air gap range of 95–215 mm is 92%–95%.