Single-Phase Grid-Connected High DC-Gain Flyback Converter for EV Battery Charging

This paper presents an AC-DC flyback converter with a half-bridge single-phase grid converter with high-DC gain for EVs battery charging applications. The converter is capable of improving the line side power factor and the current total harmonic distortion (THD) of the grid current. In the proposed model, the first stage is front end active rectifier with a reduced number of switch counts as it is a single-leg converter having high DC voltage gain. The voltage balancing across the DC link capacitor with proportional resonant (PR) control maintains the unity power factor with lower current THD. The second stage is a flyback DC-DC converter, which operates in a closed-loop constant current control mode enabling control of the battery charging current suitable for EVs applications. The total switch count of the proposed converter is reduced as compared to full-bridge conventional grid-connected converters with improved efficiency. The performance analysis of the proposed AC-DC Flyback Converter in terms of THD, power factor, and efficiency is presented with single-leg converter prototype results.