A Hybrid Transmitting Coil for Angular-Freedom Wireless Power Transfer

This letter presents a hybrid transmitting coil (HBRTx) for angular-freedom wireless power transfer. The rotating magnetic field is analyzed and obtained in different charging planes by three coil configurations to adapt the Rx rotations. Furthermore, the CLC (capacitor-inductor-capacitor) impedance matching networks (IMN) are implemented on the Tx and Rx side to match the coil impedance to the source and load impedance and improve the power transfer efficiency (PTE). Experimental results show that our proposed WPT system can supply power effectively to a distance of up to 51 mm with a maximum PTE of 80.35%. Moreover, the PTE maintains above 70% regardless of the Rx’s rotations around Ox, Oy and Oz axes, which shows the system’s flexibility and mobility.