Design and Analysis of EMI Shielding Method using Intermediate Coil for Train WPT System

In this paper, we proposed an intermediate coil to reduce third harmonic EMI component, which is the highest harmonic EMI component in wireless power transfer (WPT) system. WPT system transfers power wirelessly from Tx coil to Rx coil. When Tx part driving power, unwanted harmonic components are generated from inverter of Tx part and rectifier of Rx part. The proposed intermediate coil can effectively lower third harmonic component without degrading the WPT system efficiency. Three-dimensional electromagnetic simulation and circuit simulation are used to verify the effect of the proposed intermediate coil. Thus, we finally achieved the optimal intermediate coil, which reduce third harmonic component nearly 3 dB with 2% increase in system efficiency.