GaN-Based, Buck-LLC Resonant Design and Maximum Efficiency Point Tracking Regulation for Space Power Systems

Legacy space power systems are designed to be incredibly robust and capable of operating over a wide temperature range, in a vacuum, and with high radiation for years with extremely high reliability primarily relying on the heritage designs with older, hard switched topologies like the flyback and forward converter. Modern terrestrial systems using soft or resonant switched topologies achieve significantly higher efficiencies and power densities, and modern automotive and telecommunication systems often achieve high reliability for a more narrow temperature range without radiation concerns. This work presents the derating and design analysis for a modern Buck-LLC topology with Gallium Nitride (GaN) transistors designed for use in space applications. Finally, this work presents a control system design that adapts to changes in component values over temperature, lifetime, and radiation. By adapting the switching frequency and dead time, the converter is able to maintain high efficiency with ZVS operation. In total, these systems provide the basis for the next generation of high efficiency and robust power converters for space applications with power ranges from 100 W to 1 kW, with the potential for even higher power outputs in future work.