Design and Analysis of a New GaN-Based AC/DC Converter for Battery Charging Application

Abstract

This paper reports on the design, analysis, and characterization of a simple gallium nitride (GaN)-based ac/dc converter for battery charging applications. The proposed converter combines the merits of GaN switching transistors together with the advantages of close-to-unity power factor of a totem-pole power factor corrector, a high-frequency (HF) isolated series resonant converter, and a current doubler rectifier to reduce the copper losses of the HF transformer. The converter is designed to convert a 120 Vac input to a 48 Vdc/60 Vdc output for a 1.5 kW battery load at 65–100 kHz. Its steady-state characteristics are analyzed based on equivalent circuit and state-space models while its frequency characteristics are analyzed using MATLAB simulations. Finally, an experimental prototype is fabricated and characterized.