Analysis and Design of a Metal Object Detection Method for Wireless Power Transfer Systems

There will be eddy current effect while foreign bodies inevitably enter the gap between the transmitting coil and the receiving coil in the process of magnetic field induction radio energy transmission, which could lead to the high temperature and inefficiency of the system or even significant security risks. In this paper, a detection method of metal foreign bodies in the auxiliary coil perpendicular to the energy coil is designed. The magnetic coupling mechanism model based on MAXWELL software was built to obtain parameters of the magnetic coupling mechanism by simulation. On this basis, the Simulink circuit simulation model of radio energy transmission system is established, and its energy transmission characteristics are analyzed. Based on the designed radio energy transmission system, a detection coil perpendicular to the energy coil was designed, and its MAXWELL 3D simulation model was established to obtain its coupling characteristics. The experimental prototype is built and the metal foreign body detection experiment is conducted. The results of experiment are consistent with that of the simulation, which verifies that the vertical detection coil proposed in this paper is a feasible method for the detection of metal foreign bodies in the radio energy transmission system.