An Investigation of Electromagnetic Radiated Emission and Interference From Multi-Coil Wireless Power Transfer Systems Using Resonant Magnetic Field Coupling

Wireless power transfer (WPT) technology has recently emerged as an innovative and promising technology, and its electromagnetic compatibility (EMC) has become a significant issue. In this study, we investigated the electromagnetic (EM) radiated emission and interference generated by WPT systems using resonant magnetic field coupling, especially in applications with multi-coil configurations. The change in coil resonance associated with multi-coil configurations was analyzed via the impedance profile. We measured the EM radiated emission and analyzed the results with respect to the coil resonance. An analog-to-digital converter chip was designed and fabricated to analyze the effect of electromagnetic interference (EMI). Based on measurement and simulation results, we verified that the EM radiated emission and interference increase at the series or parallel resonance peaks, depending on the source type. In addition, we verified that EMI can be reduced by using ferrite sheet shielding.