Characterization of ZVS Behavior and Optimal Operating Point for Three-Port Current Fed Dual Active Bridge Interlinking Converter

Abstract

Current Fed Dual Active Bridge converter offers a multi port structure and can be used as an interlinking converter for connecting an LVDC microgrid with AC grid, along with the Energy storage system. Operation at the optimum point (d1, d2δ) can allow achieving multiple objectives like operation under Zero Voltage Switching (ZVS) and minimizing current stress along with controlling the power flow. While operating as a multi port converter, the electrical quantities are the voltages and currents at various ports, all of which determine occurance of ZVS and the resulting current stress. The optimal control value set (d1, d2, δ) depends on all these quantities, and determining it is a challange. In this paper ZVS behavior and current stress of CF-DAB converter are analyzed under various operating conditions pertaining to different source currents and load power. Based on the analysis, an algorithm has been proposed for determining the optimum (d1, d2δ) for the required power transfer and voltage gain. Simulation results performed on PLECS have been presented, which validates analysis and the proposed algorithm.