A simple decoupling control method for isolated three-port bidirectional converter in low-voltage DC microgrids

Multi-port isolated H-bridge converter has the features of high voltage conversion ratio, bidirectional power flow and high-power capacity, which is suitable to be integrated into DC microgrids. This paper uses three-port isolated H-bridge converters as the interfacing converters in power generation units which comprise distributed generation (DG) and energy storage (ES) in DC microgrid. The topology and phase-shifting control of this three-port converter are introduced at first. After this, the equivalent model is presented, and on this basis, a decoupling control method is proposed to eliminate the coupled power flow of each port. As a result, under the decoupling equation and the closed-loop control, the system transient performance is improved. Simulation studies are implemented to demonstrate the validity of the proposed control method.