A Near Field Analytical Model for EMI Reduction and Efficiency Enhancement using an Nth Harmonic Frequency Shielding Coil in a Loosely Coupled Automotive WPT System

In this article, we propose a near field analytical model of an electromagnetic interference reduction method using an nth harmonic frequency shielding coil with efficiency enhancement in a loosely coupled automotive wireless power transfer system. In general, in the loosely coupled automotive wireless power transfer system, the power transfer efficiency is relatively lower than a tightly coupled wireless power transfer system due to the low coupling. In addition, the electromagnetic interference at the nth harmonic frequency from the power source can interfere with nearby electronic devices. To reduce electromagnetic interference level and enhance efficiency, we proposed a shielding coil between a transmitter and a receiver coil. By using a near field analytical model of the magnetic field intensity and efficiency equations, we analyze based on the equations and obtain a proper value of the resonant frequency of the shielding coil. Therefore, we can achieve low levels of electromagnetic interference at the specific nth harmonic frequency and higher value of the power transfer efficiency in the loosely coupled automotive wireless power transfer system.