A Dual-Band Direction Changeable Wireless Power Transfer Device with High Efficiency

To fulfilling the high efficiency of direction changeable wireless power transfer (WPT), a system of dual-band with several printed circuit board (PCB) planar coils through the magnetically coupling resonance (MCR) is proposed through deducing and simulation. The efficiencies of the two bands of 6.78MHz and 13.56MHz are both more than 92% when the distance between the two coils is about 3/5 profile dimension. Any planar or spatial direction alteration of WPT systems can be achieved by using this kind of method. Especially, the 90° and 180° changed direction cases are put forward through four and seven PCB planar coils with angular changing of 30° between every adjacent two coils, respectively. The power transmission efficiencies for two bands of 6.78MHz and 13.56MHz in four relay coils system with total 90°direction variation are more than 81.8% and 71.5%, respectively. While the efficiencies of 6.78MHz and 13.56MHz bands in seven relay coils system with 180°direction changing are about 82.6% and 53.8%, respectively.