A Novel Three-Phase Three-Layer Topology for Wireless Power Transfer Systems

Recently, research on multi-phase and multi-layer structures has been underway for wireless high-power transfer. Since wireless power transfer (WPT) is proportional to the area of the transmitter and receiver pads, multi-phase and multi-layer couplers are suitable solutions for increasing power density. However, multi-phase and multi-layer topologies face issues such as interphase coupling, which does not contribute to power delivery, and cross-coupling, which contributes to power delivery but creates unbalance in magnetic field distribution. Interphase coupling complicates resonance circuit designs more than in single-phase systems, while cross-coupling causes load unbalances. In this article, a three-phase three-layer (3P3L) coupler is proposed, and the efficiency of the couplers is increased by minimizing the interphase coupling. Furthermore, load unbalance due to cross-coupling is mitigated through relative phase control of the three-phase inverter. An experimental prototype of the proposed 3P3L system is constructed with the power capacity of 150 kW and the results are provided to validate the 4feasibility of the system.