Analysis of Electromagnetic Force on Metal Objects in Vertical Direction of Wireless Power Transfer

The interaction between the space coupled magnetic field and the moving charge will inevitably cause the metal foreign objects entering the wireless power transfer (WPT) system to be affected by the electromagnetic force. Metal objects will produce a certain trajectory under the force, which poses a serious threat to the safe operation of the system. At the same time, it also brings a difficult problem to foreign object detection technology. This paper analyses the characteristics of electromagnetic force on metal objects in vertical direction of WPT system. Firstly, the analytical computational models of ferromagnetic and non-ferromagnetic foreign objects subjected to electromagnetic force are obtained and investigated. Then, the interactive effects of conductivity and permeability of metal foreign objects on electromagnetic force are explored and verified by simulation and experiment. This research is benefit for the operation safety and reliability of WPT system.