Multi-port converter integrating two PWM converters for multi-power-source systems

Multi-power-source systems containing multiple power sources and batteries have been attracting significant attentions since the advent of renewable energy systems and electric vehicles. Multiple converters in proportion to the number of power sources are necessary in such systems, resulting in increased complexity and cost. Multi-port converters (MPCs) combining multiple converters into a single unit have been reported to achieve simplified systems at lower costs. However, the necessity of a transformer, low effective duty cycle operation, and no common ground issues are of great concern in the conventional MPCs. This paper proposes the MPC integrating two PWM converters for multi-power-source systems. The two converters can be integrated into a single unit by sharing switches without employing a transformer, hence simplifying the circuit. Depending on the power balance among each port, the MPC operates either in three operation modes. Detailed operation analyses were performed separately for these three operation modes. A 240-W prototype was built, and the experimental results agreed well with those of the analysis.