Research on Living Object Detection Technology in Wireless Charging System of Electric Vehicles

Wireless power transmission(WPT) technology is the future development direction of electric vehicle(EV) charging method. To address the current problem of biological health hazards of strong magnetic fields between wireless charging coils of EVs, this paper proposes a method for living objects detection(LOD) in EVs based on a comb capacitor sensor, using two rows of 2n comb capacitors as sensing elements, while the upper and lower rows have different structures of sensing elements and matching them with different resonant inductors. The change in capacitance of the sensing elements is converted into an offset of the differential output voltage AU from the threshold value by means of resonant amplification, high-pass filtering, differential amplification and other active circuits. Simulations in COMSOL and Simuliink demonstrate that this method can effectively detect living objects in EV wireless charging systems and eliminate the detection blind area caused by conventional differential structures.