Limiting magnetic exposures using ferrite core and shielding in wireless charging of mobile phones

Abstract

AbstractThe frequent cable breaks and socket failures experienced by users of mobile devices such as smartphones and tablets have become a problem. In this study, wireless charging of mobile phones is provided with inductive coupling. The wireless power transfer (WPT) system has a diameter of 5 cm, operates at 10 MHz, and has an output power of 5 W. The coil design includes a ferrite core and shielding for reducing electromagnetic scattering. The paper used mathematical calculations and simulation tools, including MATLAB, Simulink, Maxwell 3D, and HFSS, to analyze the WPT design and its effects on human health at various conditions. As a result, the magnetic exposure was kept below the limit value in this WPT design, thus protecting the person and the device. In addition, the WPT design achieved high efficiency with a maximum air gap of 2 cm when aligned, and up to 2 cm misalignment at 0.5 cm air gap.