Foreign Object Detection in Wireless Power Transfer Systems
Jianghua Lu, Guorong Zhu, Chris Mı
Abstract
The successful commercialization of wireless power transfer (WPT) technology in mobile phones, laptops, and electric vehicles requires a safe, reliable, and efficient charging infrastructure. A metal object, such as a coin, a key, or a nail, however, may be inadvertently exposed, by close proximity, to the magnetic fields generated by the WPT coupler, creating a potential safety hazard and affecting the electrical characteristics of the WPT system. In addition, the magnetic fields may produce adverse symptoms, such as dizziness and breathlessness, in living objects near the charging systems. This article provides a current state of the art review of all available designs for detecting metal and living objects in WPT systems. Working principles and qualitative comparisons in terms of sensitivity, accuracy, and cost of major detection methods are presented to reveal their inherent limitations and available applications. Finally, a number of research topics on foreign object detection are suggested to encourage more researchers to make contributions to the development and commercial application of wireless charging systems.