Analysis and control of multi-level dual active bridge DC-DC converter

Abstract

Dual Active Bridge (DAB) dc-dc converter finds applications in the intermediate high frequency link power conversion stage of a high-power solid state transformer. In this paper, a multilevel DAB dc-dc converter is proposed. A three-level neutral point clamped (NPC) inverter topology has been used in the high voltage bridge which enables semiconductor switches to be operated in higher voltage range without using cascaded bridges and multiple DAB converters. Modulation strategy to control power flow between the active bridges with one of the bridges switching at multi-level is proposed in this paper. Steady-state analysis of the converter with the proposed modulation scheme is presented along with simulation results to augment the analysis.