Modeling and Analysis of 2/3-Level Dual-Active-Bridge DC-DC Converters with the Five-Level Control Scheme

Two-three (2/3)-level dual-active-bridge (DAB) DC-DC converters have high potential to become a promising solution for medium-voltage DC (MVDC) systems. In this paper, the operating constraints based on the switching characteristics of the 2/3-level DAB converters are analyzed comprehensively with a five-level control scheme, in order to ensure stable and reliable operation. Furthermore, to reduce the complexity of the modeling, a unified power-transfer model is derived based on an equivalent method, and five operating modes are divided, being the references for reliable and efficient control. Simulation results verify the effectiveness of the operating constraints and accuracy of the proposed model.