(A) frequency selective EMI reduction method using resonant frequency control of a shielding coil in tightly coupled wireless power transfer system

Abstract

Current wireless power transfer (WPT) technology is widely used for various applications because of convenience and safety. Especially, the tightly coupled WPT systems are applied to a various applications. Electromagnetic interference (EMI) issues are inevitably generated in tightly coupled WPT system due to the increased transfer power of the tightly coupled WPT systems. Several solutions are proposed for settling the problem. The previous solutions have fragmentarily resolved the weakness of the tightly coupled wireless power transfer system, but they decrease the WPT system efficiency for low EMI. This research has proposed the frequency selective EMI reduction method using resonant frequency control of a shielding coil, and I analytically propose the design procedure for maximum efficiency and minimum EMF level at the specific frequency range. Moreover, for the validity of the proposed shielding coil, I have proved the same tendency with simulation result and measurement result. With the proposed design process and equations, the proposed shielding coil can be designed for other tightly coupled WPT system with high efficiency and low EMF level at specific frequency range.