Position detection (PD) and foreign object detection (FOD) functions are the key to ensuring the efficient and safe operation of electric vehicle wireless power transfer (EV-WPT). However

most of the researches focus solely on a single function without considering the increased structural and logical complexity after multi-function integration. To this end

this paper proposes a position and foreign object integrated detection system for EV-WPT system based on the time-division multiplexing of the detection coil array. In PD function

a beacon coil is installed on the secondary side of the EV-WPT system

which generates an AC magnetic field

and induces high-frequency voltages on the detection coil array. A power-enhanced weighted center-of-mass positioning algorithm calculates the relative positions between the primary coil and secondary coil based on the sampled voltages from detection coils. In FOD function

a quadrature demodulation circuit separates the isotropic and quadrature DC voltage components of the detection coil and calculates the changes in the detection coil voltage amplitude A2 and the phase cotangent cotφ. A metal object (MO) causes a decrease in A2 and an increase in cotφ

while a live object (LO) causes a decrease in both A2 and cotφ. Eventually

the experimental results of the proposed system are effective: the average error of the PD function is within 10 mm in the area of 502 mm × 382 mm; the 40 mm × 40 mm iron sheet and the hand reduce the A2 by 51.8% and 59.7%

and the cotφ increases by 25.4% and decreases by 39.3%

which can recognize the foreign objects.