A Metal Object Detection System with Multilayer Detection Coil Layouts for Electric Vehicle Wireless Charging

Bo Cheng, Jianghua Lu, Yiming Zhang, Guang Pan, Rakan Chabaan and Chunting Chris Mi
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Bo Cheng: Department of Electrical and Computer Engineering, San Diego State University, San Diego, CA 92182, USA
Jianghua Lu: Department of Electrical and Computer Engineering, San Diego State University, San Diego, CA 92182, USA
Yiming Zhang: Department of Electrical and Computer Engineering, San Diego State University, San Diego, CA 92182, USA
Guang Pan: School of Marine Science and Technology, Northwestern Polytechnical University, Xi’an 710072, China
Rakan Chabaan: Hyundai-Kia America Technical Center, Inc., Superior Township, MI 48198, USA
Chunting Chris Mi: Department of Electrical and Computer Engineering, San Diego State University, San Diego, CA 92182, USA

Energies, 2020, vol. 13, issue 11, 1-16

Abstract: Non-radiative inductive power transfer is one of the most studied and commercially applied wireless charging technologies, where the magnetic field is employed as the medium for power transfer. In the wireless charging of electric vehicles, the strong magnetic field will heat up any metal items falling in the charging area due to eddy current induced in the metal objects, causing hazards like fire. Metal object detection (MOD) is necessary for the market penetration of inductive power transfer technology. This paper aims to improve the performance of systems that detect metal objects based on inductance variations. Two novel multi-layer detection coil layouts are proposed, which can not only cover the entire charging area without blind spots but can also be decoupled from the transmitter and receiver to minimize the influence of the magnetic field that is used for power transfer. Two mixed resonant circuits are proposed and proven to have better performance than parallel and series resonance. The impacts of the detection coil layer, trace width, and turn-number are investigated. The test results indicate that the MOD system can detect one-cent coins at various positions of the detection coil printed circuit board, and can also detect various inductance variations without blind spots in the processing circuit.

Keywords: multi-layer detection coil; inductance variation; metal object detection; wireless charging; inductive power transfer (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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