Three-Dimensional Wireless Power Transfer System Using Multiple Orthogonal Resonators for Spatial Freedom

In this paper, the three-dimensional (3D) wireless power transfer (WPT) system using multiple orthogonal resonators for spatial freedom is proposed. The proposed transmitter comprises three orthogonal resonators with a 3D structure. The three orthogonal resonators are positioned on top and bottom of the substrate, and the proposed system has an open box-shaped structure due to the 3D resonators. The proposed WPT system allows power transfer despite the receiver's lateral and angular misalignment by generating magnetic fields in all directions generated by multiple resonators. For the performance verification, the operating principle of the proposed WPT system is theoretically calculated, and simulated. Also, the power transfer efficiency (PTE) under the lateral and angular misalignment is measured and is compared with the conventional WPT system and WPT system implemented on the two-dimensional plane using the multiple orthogonal resonators. The proposed WPT system achieves a PTE from 46.8% to 71.6% when the receiving resonator is set to 81×51 mm 2 that can be built into the mobile phone, and the charging volume is 201×201×51 mm 3 .