Design and Implementation of Near-Field Spatial Wireless Power Transfer Using Orthogonal Multiple Coils

In this paper, we propose a three-dimensional (3D) wireless power transfer (WPT) system using highly isolated orthogonal coils for expanding spatial freedom. The proposed transmitting coil is arrayed with highly isolated orthogonal coils. The proposed 3D WPT coil can transmit the power to the receiving coil regardless of lateral and angular misalignments of receiving coil through all directions magnetic fields generated by isolated coils. For the performance verification, the power transfer efficiency (PTE) under the lateral and angular misalignments in the operating area is measured and compared with the conventional WPT system and the proposed 3D WPT system. The proposed 3D WPT system is matched at 6.78 MHz and achieves approximately 50% or more PTE regardless of all lateral and angular misalignments when the receiving coil is set to 180×180 mm² and the PTE is measured in the operating area of 300×300×300 mm³.