A Solid-State Transformer Architecture Based on Quadruple Active Bridge Converters

Abstract

With the expanding adoption of renewable energy sources and DC loads, future electrical power systems are gradually heading toward medium-voltage direct current (MVDC) architectures. This article presents and analyses a modular isolated DC/DC converter topology incorporating energy storage for the interconnection of MVDC networks. Accordingly, modularity, high power density, galvanic isolation, and power management capabilities are crucial to guarantee system flexibility, reliability, and scalability. The proposed structure is founded on a power electronic building block (PEBB) built from two Quadruple Active Bridge (QAB) converters operating within an Input-Series Output-Series (ISOS) configuration, which could be further cascaded to handle higher voltage levels and power rating. The suggested QAB-based structure contains an internal hybrid energy storage system combining batteries and supercapacitors. Furthermore, specific control and power flow among the multiple ports of the QAB ensure balanced operation in the ISOS configuration, and optimally distribute power between storage.