Abstract
Due to the open structure of wireless charging systems, foreign objects are inevitably involved. In the process of energy transfer, the intervention of metal foreign objects will cause the system to deviate from the normal operating point and even cause safety accidents. Therefore, metal foreign objects detection (MOD) technology is of considerable importance. In this paper, a metal foreign object detection system of a wireless power transfer (WPT) system based on the symmetrical detection coil was designed, and a MOD method based on frequency scanning is proposed. The coil size of the WPT system was designed based on SAE-J2954 standard. In addition, the suitable detection coil was installed at the transmitting coil. The system model was established in ANSYS simulation software, and 5 cm × 5 cm copper sheet and iron sheet were used as the metal to be detected. The result shows that the self-induction of the detection coil at the position of the foreign object can achieve a fluctuation of 52.46% and −34.72%, and the resonant frequency of the detection system is offset by 24.7% and −18.82%, respectively. Finally, the experimental platform of MOD system was built, and the effectiveness of the system was verified.
Highlights
The development of wireless power transfer (WPT) technology is gradually maturing
The metal foreign objects detection (MOD) system proposed in this paper is beneficial to improve the security of the electric vehicle (EV)-WPT system
When the non-ferromagnetic metal is near the transmitting coil, the impedance parameters of the transmitting coil will be affected by the eddy current effect of the metal [19]
Summary
The development of WPT technology is gradually maturing. In particular, the magnetic coupled resonant (MCR) transmission mode has made remarkable improvement in power level, transmission efficiency, anti-migration performance, and so on [1,2,3,4]. The MCR-WPT system transmits the energy of the transmitting coil to the receiving coil through electromagnetic induction coupling, and the resonator generates a strong alternating current magnetic field [5]. The voltage difference between each detection coil group was used to detect the position of foreign object, which can reduce the design complexity This scheme had a blind spot in detection [15]. Reference [18] proposed a multilayer detection coil layout that covered the entire charging area to eliminate blind areas, and could be separated from the transmitting and receiving coils to minimize the impact on the magnetic field of the energy-transmitting coil. In order to identify the position and type of foreign objects, this paper adopts the method of detecting coil, establishes the suitable detecting coil arrangement, and designs the detection circuit to achieve higher detection accuracy. The MOD system proposed in this paper is beneficial to improve the security of the EV-WPT system
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
