Metal Foreign Object Detection in Electric Vehicle Wireless Power Transmission

Wireless power transfer technology has developed rapidly as a novel technology for its safe operation, flexibility, convenience and low maintenance cost. The electric vehicle wireless power transfer system transmit energy relying on high-frequency electromagnetic field. However, it may cause the hidden danger of temperature rise and fire, and even affect the parameters of the coupling structure, leading to the deviation of the working point, if any metal foreign objects accidentally entering the energy transmission area. In view of the above problem, the metal foreign object detection technology of electric vehicle wireless charging system was systematically discussed in this paper. The influence of metal foreign matter entering the magnetic coupling mechanism was analyzed. Then the technical route of foreign object detection at home and abroad was summarized. This paper also focused on the analysis of the detection method based on the characteristic parameters of the detection coil. Finally, the technical challenges including coil offset and points picking were discussed.