Integrated Design of Double-Layer FOD Coil and its Excitation Frequency Selection for MC-WPT System

-Foreign object detection (FOD) is essential for the efficient and safe operation of MC-WPT system. For high-power applications, like electric vehicle wireless charging system, the externally excited array detection coil is an effective method for FOD. However, the need to turning capacitors for each array coil increases the complexity of the detection coil routing and occupies a certain amount of space. Besides, a single fixed detection excitation frequency cannot effectively handle parameter drift caused by environmental influences on the detection coil. To fix these problems, a design of integrated inductance and capacitance for a double-layer PCB detection coil is proposed, along with its corresponding optimal excitation frequency selection scheme. The proposed coil presents the LC-parallel characteristic without additional tuning capacitors, which improves the integration of the system while also ensures high sensitivity. As for the optimal detection frequency, this paper determines it by the impedance near detection coil's self-resonate frequency.