Modeling, synthesis and operation of multiport-active bridge converters

• Modellierung, Synthese und Betrieb von Multiport-Active-Bridge Wandlern

Neubert, Markus; de Doncker, Rik W. (Thesis advisor); Biela, Jürgen (Thesis advisor)

Aachen : ISEA (2020)
Book, Dissertation / PhD Thesis

In: Aachener Beiträge des ISEA 152
Page(s)/Article-Nr.: 1 Online-Ressource (ix, 227 Seiten) : Illustrationen, Diagramme

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2020

Abstract

Multiport-active bridge (MAB) converters connect dc sources and loads of different voltage and power ratings. They enable a multi-directional power flow, provide galvanic isolation and are capable of buck and boost operation. In addition, MAB converters spare resources and are cost effective. Hence, they are a key component for future dc grids. This thesis proposes a modeling methodology to precisely determine the load angles and the power flow of MAB converters. The proposed methodology is used to synthesize the characteristic behavior of a three-phase three-port MAB converter, i.e., a three-phase triple-active bridge (3ph-TAB) converter, in detail. Moreover, a generalized zero-voltage switching operation strategy is derived that significantly increases the efficiency of MAB converters at low loads and unequal port voltages. Following the optimization of the steady-state behavior, the precise knowledge of the load angles is used to implement an instantaneous current control. The current control enables a full load step at each port of a MAB converter within one switching period and without causing oscillations of the dc-link currents. The theoretical analyses and simulation results are verified by measurements on a developed test setup that consists of two 3ph-TAB converters in back-to-back connection, incorporating a 5 kV medium-voltage port and two low-voltage ports with a nominal voltage of 380 V and 760 V.