Operation and Comparison of a Novel Modular Asymmetric Buck-Boost DC-DC Converter for High-Power Applications

Modular converter with dissimilar modules have shown a lot of promise in recent studies. This paper presents a comparative evaluation between a novel input-parallel output-series (IPOS) asymmetric buck-boost bidirectional dc-dc converter and the conventional non-inverting buck-boost (NIBB) bidirectional dc-dc converter. The proposed converter is formed by an IPOS connection of an NIBB module and a boost module. The two modules are operated in three optimized modes depending on the output voltage requirement: buck/pass-through mode, boost/pass-through mode, and boost/boost mode, with smooth transitions between the various modes. The proposed converter and the NIBB converter are compared based on the voltage gain, active switch utilization, total passive component energy ratings, and power conversion efficiency over a wide range of output voltage and power levels. The results indicate that the proposed converter can offer better overall efficiency, with reduced stress on semiconductor devices and lower filter size. The operation of the proposed converter is verified in simulation and experiment.