Design of Compact Magnetic Coupler with Low Leakage EMF for AGV Wireless Power Transfer System

Severe leakage electromagnetic field (EMF) generated by automatic guided vehicle wireless power transfer (WPT) systems is hazardous to the surrounding objects. To reduce the leakage EMF, a novel compact magnetic coupler is proposed in this paper. The idea of this work is, firstly, adopting the compensation inductors of the LCC-LCC compensated WPT system as EMF canceling coils, and EMF alleviation can be achieved without any additional components; secondly, integrating the power transfer coils and the EMF canceling coil into one magnetic coupler to compact the system. An experimental prototype is fabricated to verify the EMF shielding effect of the proposed magnetic coupler. Experimental results show that compared with that of the general magnetic coupler, the EMF of the proposed magnetic coupler is dramatically reduced by 82.24% at maximum and by 75.18% on average from y=200mm to 350mm. Besides, the transfer efficiency is decreased by 0.32% only with the same output power. That means the proposed magnetic coupler can effectively alleviate the EMF without a significant negative impact on the transfer efficiency.