Efficiency-Optimized Control Method for Multiport Converter with Current-Fed H-bridges

In this paper, an efficiency-optimized control method for multiport converters with current-fed (CF) H-bridges is proposed to implement highly efficient low-voltage DC (LVDC) power supply system in residential area. The CF H-bridges of the multiport converter can deal with the wide voltage range of various renewable energy sources (RESs) with greatly reduced current ripple. However, they utilize many passive components, which degrades the power conversion efficiency of the multiport converter. Considering the steady-state operation of the CF H-bridges, the proposed control method can suppress the conduction loss from many passive components and provide a zero-voltage switching (ZVS) capability for the CF H-bridges. Besides, the proposed method can control the output voltage and power only with a single control variable, so that it can drastically reduce the computation burden of a processer. The experimental results using a 1.5-kW prototype multiport converter verify the enhanced power conversion efficiency using the proposed method.