Design and analysis of a new GaN-based AC/DC topology for battery charging application

Gallium nitride (GaN) technology reduces switching losses and allows faster device switching speeds. Meanwhile, high frequency (HF) transformers feature reduced weight and size for many applications. In this paper a new GaN-based power supply topology for battery charging applications is designed, simulated, analyzed, and constructed. The proposed topology is designed for 120Vac to 48Vdc/60Vdc conversion, operating at 100 KHz in the 1.3-1.5 kW range. A totem-pole power-factor-correction (TP-PFC) active front-end is utilized to yield close-to-unity power factor (~0.98) and higher efficiency with reduced harmonic content. This work designs and analyzes a new topology to combine the advantages of GaN TP-PFC and a high-frequency series resonant converter (SRC) with current doubler rectifier (CDR) utilizing the superior switching characteristics of GaN devices and the reduced size and cost of HF transformer. A loss-free resistor model is used to determine keys steady state and the main characteristics of the proposed topology.