Nonisolated PWM Three-Port Converter Realizing Reduced Circuit Volume for Satellite Electrical Power Systems

Abstract

Three-port converters (TPCs) combining two dc–dc converters into a single unit is a promising solution that can simplify and miniaturize satellite electrical power systems. Conventional nonisolated TPCs, however, face a variety of challenges, such as the necessity of a transformer, low effective duty cycle operation, and unshared ground issues. This article proposes a novel nonisolated TPC integrating a unidirectional and bidirectional pulsewidth modulation converters. The two converters can be integrated into a single unit with reducing total switch count without employing a transformer, thus achieving the simplified circuit. In addition, thanks to the capacitor added in series with switches, not only the voltage stress of semiconductor devices is reduced, but also miniaturized inductor design is feasible. The quantitative analysis revealed that the volume of passive components in the proposed TPC could be reduced by approximately 19% compared with a conventional nonisolated TPC. A 240-W prototype was built for the experimental verification, and the results agreed well with those of the analysis, demonstrating its efficacy.