7.2 kW GaN-Based DAB Converter with 37 kW/L Power Density and High Efficiency

This paper presents a GaN-based high power density and isolated DC-DC converter with dual active bridge topology for DC/DC stage of a bidirectional 400V EV on board charger (OBC). Gallium Nitride (GaN) technology in top side cooled package is employed to achieve higher switching frequency with more compact passive components solutions. The paper introduces the design parameters for the DAB circuit with wide range output, variable frequency controller as well as two high frequency planar transformer designs to achieve 125 kW/L power density. System level loss breakdown and circuit protection scheme and implementation are also provided. The 7.2kW DAB prototype has been implemented and tested in constant voltage (CV) mode, proving exceptional power density of 37 kW/L with 98.8% peak efficiency.