Toward interconnected DC grids: modeling, advanced control methods, and a transformer design framework for multi-active-bridge converters

RWTH Publications (RWTH Aachen)

Abstract

The efficient energy supply of the future requires a cost- and resource-efficient interconnection of DC grids. Multi-Active-Bridge (MAB) converters represent a promising solution, as they provide galvanic isolation, bidirectional power flow, and high efficiency. However, their inherent complexity – arising from numerous degrees of freedom in design and modulation – as well as the lack of accurate models for design and control, have so far hindered the practical implementation of this topology. Against this background, the aim of this dissertation is to make the MAB topology applicable in practice. Using a novel modeling approach, the behavior of the converter can be described with high accuracy. In addition, a transformer design toolchain has been developed, which determines computationally efficient optimal multiport transformers through the superposition of FEM simulations and genetic optimization. Furthermore, steady-state and dynamic control strategies have been developed to enable efficient and soft-switching operation of the converter. Measurements on a three-phase four-port MAB validate these methods and confirm the MAB as a promising technology for future energy supply.

Authors 1

1. André Thönnessen corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen