Shielding Analysis of High-Frequency Coaxial Transformers Used for Electric Vehicle On-Board Charging Systems

This paper introduces a high-frequency coaxial transformer (HFCT) with a power efficiency of >99.5% and an operational frequency between 100-300 kHz. The power rating of the HFCT can be easily scaled from 2.5 to 20 kW by adapting its simple symmetrical structure. The introduced HFCT is suitable for use with converters in electric vehicle on-board charging systems. It easily fulfills the design requirements of being lightweight, compact, and having a high power density and achieved a volume reduction of 75% in comparison with commercial products Furthermore, the electromagnetic interferences are increasing with the increased operating frequency, and an inserted copper Faraday shield is used to deal with this issue (an 80.6% reduction of intra-winding capacitance was achieved). A shielding analysis, with a focus on the insertion losses, is undertaken by utilizing finite element method based numerical techniques.