A Isolated Bidirectional DC/DC Converter with Low-Voltage IGBTs for Solid-State Transformers

Abstract

In order to reduce footprint and improve efficiency, solid-state transformer (SST) is an attractive technology for traction and smart grid applications. As the key components of SST, the conventional isolated bidirectional DC/DC converter (IBDC) is hard to guarantee high efficiency and high power density at the same time, due to the limitations of switching characteristics of semiconductor devices and high insulation requirements of medium frequency transformer (MFT). In this paper, a new IBDC topology is proposed, which is characterized by utilizing low-voltage IGBTs with excellent switching characteristics to build high voltage configuration. This helps to reduce the number of the MFTs. Meanwhile, the zero-current switching (ZCS) conditions for all the IGBTs can be guaranteed. This significantly reduce switching losses. The operation principles of the proposed IBDC are analyzed, and the feasibility is verified by simulation results.