Abstract

In this paper, a three-dimensional diagonalized transmitting coil (DAG-Tx) structure is proposed for improving angular free-positioning in a wireless power transfer (WPT) system. The magnetic field distribution is analyzed to transfer power effectively to a rectangular receiver (Rx) in spatial freedom. A mathematical method is adopted to calculate mutual inductance between the proposed Tx and rectangular Rx. In addition, the inductor-capacitor-capacitor (LCC) and capacitor-capacitor (CC) impedance matching networks are proposed and implemented on the Tx and Rx sides to improve the power transfer efficiency (PTE). Experimental results show that the WPT system can transfer with PTE of up to 80% in a face-to-face transmission distance of 100 mm. Moreover, the PTE maintains above 70% by rotating Rx from 0 o to 135 o around three coordinate axes.