Multi‐port DC–DC converter for bipolar medium voltage DC micro‐grid applications

Abstract

In this study, a new bipolar DC-DC converter based on the combination of a multi-port dual active bridge and a neutral point clamp topology is proposed. This topology provides the integration of multiple renewable energy sources, with different types and capacities, to a bipolar medium voltage DC micro-grid. The main advantages of the proposed topology are its high power density and the reduced number of switches with respect to the combination of different converters. Moreover, it provides isolation which is crucial for some micro-grid power conditioning converters. The proposed converter is employed for a typical hybrid generation system consisting of a photovoltaic (PV) system, a fuel cell (FC), and a battery (BAT) considering the characteristics of each power generation system like maximum power point tracking of PV, optimum operating region of FC and over-charge/discharge of BAT. In addition, the proposed converter is simulated in different power sharing modes in MATLAB/Simulink software environment. Eventually, the theoretical and simulation analyses are validated by experimental prototype results.