Cross interference suppression methodology by printed circuit board type metamaterial in multi‐frequency multi‐load magnetically coupled resonant wireless power transfer system

Abstract

Abstract The prosperity of market in multi‐charging devices has made the researches on multi‐load magnetically coupled resonant (MCR) wireless power transfer (WPT) technique be an urgent issue nowadays. For the sake of load recognition and controllable power distribution, the concept of multi‐frequency excitation was introduced into multi‐load MCR WPT systems. However, the transferred power components at different frequencies inevitably suffer the cross interference at receivers, which negatively affects the accuracy of load recognition and power distribution. To suppress the cross interference, a methodology by using the metamaterial composed of a printed circuit board (PCB) spiral inductor and a lumped capacitor was proposed. The concept of equivalent mutual inductance (Meq) was presented to quantitatively describe the influence of metamaterials on the couplings between the transmitting (Tx) and receiving (Rx) coils. By magnetic field simulation, a series of Meq curves versus operating frequency under different metamaterial parameters were plotted and an optimal design was adopted to suppress the power components at non‐targeted frequencies. Moreover, a detailed circuit model was built to characterize the output power of multiple loads after introducing the metamaterial. Finally, the experiments from a prototype was carried out and the experimental results verified the effectiveness of proposed suppression methodology.