A Novel Mechanism and Method of Metal Foreign Object in Wireless Charging System Based on Harmonic Aggregation Peak

In order to solve the performance degradation or operation security caused by the presence of metal foreign objects, this paper proposes a metal foreign object detection method based on the harmonic aggregation peak for the LCC-S wireless charging system, which is different from the existing methods such as detecting coils. Aiming at characteristics that the intrusion mainly affects the fundamental component, but has little impact on the high-order harmonic component, an impact model is established by analyzing the impact of foreign metal objects on the output current of the inverter side. The experimental result shows that, the method proposed in the paper can effectively identify the common metal objects including tea boxes, insulated cups, cans, etc., which proves the feasibility and operability of current sampling for foreign object detection.