A Novel Coupling Factor Independent Highly Efficient Resonant Based Wireless Power Transfer

This paper presents a novel design methodology to address range and misalignment intolerance in strongly coupled magnetic resonance wireless power transfer (WPT) systems. A nonlinear resonator circuit is developed to compensate for the effect of coupling factor (k) variation between the transmit and receive coils and thereby maintaining high efficiency of WPT system. Such a method is implemented with an all passive circuit configuration without altering the operating frequency. The method is experimentally verified using a WPT circuit designed at 3.65 MHz. A near-constant wireless power transfer efficiency higher than 75% is achieved over 18 cm of transfer distance, exhibiting significant improvement as compared to a conventional linear WPT circuit operating under the same conditions.