A Hybrid Detector Array for Simultaneous Detection of Living and Metal Object in Wireless Power Transfer Systems

This paper proposed a sensing unit of Foreign Object Detection (FOD) for Wireless Power Transfer (WPT) systems that works for both Metal Object Detection (MOD) and Living Object Detection (LOD). Based on the proposed sensing unit, an adaptive excitation and detection algorithm is presented, where the exicitation signal with selectable frequencies components is generated to improve the detection rate of random Metal and Living Objects (MOs and LOs). Using the proposed sensing unit and the detection algorthm, the detection system works like a simplified impedance analyzer, which ultilizing the equivalent LC network of sensing unit as probe to detect the impedance variation due to the inductive coupling between MO and sensing unit's coil, as well as the capacitive coupling between LO and sensing unit's copper strip. Compared with conventional MOD and LOD systems, the detection system in this work has the advantages of reduced system complexity (using one sensing unit for both MOD and LOD, thus only one signal processing path is necessary) and improved sensitivity, especially in weak detection positions (e.g. boundaries of sensing components).