Transient Bias Suppression Optimization for Bidirectional 2/3-Level DC-DC Converters

The bidirectional 2/3-level DC-DC converter has attracted more and more attention because of its high power conversion ratio and lower switch stress compared with traditional DC-DC converters. It can be a good can-didate as the next power conversion interface for medium-voltage DC (MVDC) systems. Due to the changes in the phase-shift (PS) ratios, the traditional PS control may result in the dc-bias current in the transient-state. In order to solve this problem, the mechanism process of the dc-bias current during the transient-state will be analyzed first in this paper. Based on this analysis, the transient bias suppression optimization (TBSO) strategy will be proposed to mitigate the biased inductor current. Finally, simulation verification will be provided to prove the effectiveness of the proposed strategy.