A Novel Current-Fed Three-Level Dual Active Bridge Converter with an Auxiliary Inductor for Energy Storage System

Abstract

This paper proposes a new current-fed three–level (3L) dual active bridge (DAB) converter topology with auxiliary inductor for DC micro grid application. 3L output in the proposed converter gives higher DC voltage compared to the conventional 2L output and it offers additional control degree of freedom. All the possible operational modes of this converter are derived. One of these operating modes is analyzed in detail with current and power expressions. Different voltage-fed (VF) and current-fed (CF) DAB-derived DC-DC converter topologies are compared with the proposed converter in terms of various design and performance parameters. Simulation results show lower input current ripple and wider ZVS range in the proposed converter compared to the VF DAB converter. The secondary side voltage in the proposed converter are found to be balanced in contrast to the CF 3L DAB without auxiliary inductor.