A T-type dual active bridge with symmetrical configuration for solid state transformer

Abstract

ABSTRACT Solid-state transformer has been a major area of research in recent years because of its multifunctionality as compared to conventional low-frequency transformers. Bidirectional isolated dual-active bridge is an important component in power electronic transformer. When conventional control scheme such as single-phase shift and dual-phase shift are used, they have high current stress and thus reducing the system efficiency because of high circulating power. Furthermore, they have high across switches, with only one or two degrees of freedom. It confines its ability to regulate power flow. In this paper, a new T-type dual-active bridge with symmetrical configuration is proposed, having five degrees of freedom which not only improves its ability to regulate power flow, but also reduces across switches due to increase in voltage levels, and has lesser current stress. It reduces the circulating power which improves the efficiency of system. Detailed analysis to establish the relation between controllable variables with current and power flow is given in this paper. Performance of the proposed converter has been verified via simulation and experimental results.