Analysis and Design of a Condensed Buck-boost Converter Utilizing Monolithic Bidirectional GaN Switches

Many next-generation power converters require wide-range operation, capable of bidirectional power flow combined with buck and boost mode operation; thereby, supporting integration of renewable energy sources and storage on the grid and within electric drivetrains. This work presents a family of condensed buck-boost (CoBB) converters which utilize novel monolithic bidirectional switches (MBDS) to increase utilization of switches and passive components compared to conventional approaches. Moreover, multilevel CoBB converters are explored, showcasing their potential for dramatically reduced passive component requirements. The operation of the proposed converters is presented and fundamental comparisons in loss mechanisms and passive component sizing showcase the potential improvements. Moreover, a return path inductor variant is introduced to further reduce passive component requirements. Experimental hardware is presented showcasing operation of the two-level and three-level CoBB converter validating the theoretical analysis. Finally, control strategies for regulation and unity conversion ratios are provided and validated with the hardware prototype.