Leakage electromagnetic field reduction method through planar reactive shield and resonator for high power transfer efficiency in wireless charging system

Abstract

Recently, the performance of electric vehicle(EV) and consumer electronics(CE) has improved dramatically and seems to have no limit. Also these EV and CE have a significant and widespread influence on human life styles. However, these devices still rely heavily on battery operation despite its disadvantages such as the batteries’ heavy weight, and the inconvenience of charging cables and long charging times. Because of these and other battery problems, the demand and interest in wireless charging (WLC) have been rapidly increasing lately. However, WLC systems generate leakage magnetic fields, causing malfunctions in adjacent electronic devices. The interest and demand of research about suppression of radiated electromagnetic field(EMF) and electromagnetic interference(EMI) are increased. Therefore, this thesis propose a shielding method to suppress the EMF and EMI from WLC systems. In particular, this thesis propose novel single and multi resonance reactive shield using closed loop coil and capacitor. Also, the problems with conventional shielding method that degrades the power transfer efficiency is solved by using resonator located inside the source coil. The proposed shielding method using resonant reactive shield and resonator is verified using simulation and measurement and compared with other shielding methods.