Quad-Active-Bridge as the basic cell of a MMC Based SST for DER and DESS Integration

Abstract

In a solid state transformer (SST), one of the most important roles is played by the dc-dc converter interfacing the high voltage port and the low voltage port while providing galvanic isolation. This paper proposes a quad-active-bridge (QAB) converter as the basic cell of a Modular Multilevel Converter (MMC) based solid state transformer for the integration of distributed energy resources (DER) and distributed energy storage systems (DESS) into the grid. This study comprises power transfer analysis, modeling and control of the QAB for this application. Furthermore, this paper shows an alternative method based on the star-mesh transformation to built the multiwinding tranformer equivalent circuit, that relates any two ports of the multiple-active-bridge (MAB) converter through a link inductance, which allows to describe power flow. Results are obtained by simulations in PLECS.

Fully Isolated Quad-Port Electric Energy Routing Converter with Medium- and High-Voltage Grid Connection Capability

“…e above is the general equation of the topology with n ports on the low-voltage side. e equivalent circuit can be obtained by combining ( 6) and (7).…”

“…is requires the design of multiterminal energy routing devices in the DCMG distribution system. erefore, to facilitate the connection of multiple new energy sources and energy exchange between power grids, multi-port energy routing schemes based on different usage scenarios have been proposed [3][4][5][6][7][8]. Reference [3] introduced an energy routing topology for wind storage grid-connected system, using a full-bridge power converter to implement an independent hybrid renewable energy DC grid system with battery storage.…”

“…Liu et al [6] proposed a solid-state transformer topology based on quad-active bridge (QAB), including the power transmission analysis, modelling, and control strategy of QAB and presented a new equivalent model of multiwinding transformer. Frutos et al [7] designed a linear quadratic regulator controller for a quad-port converter based on the average equivalent model of QAB, and the control strategy can resist step disturbance.…”

Three-Phase UPQC Topology Based on Quadruple-Active-Bridge

“…Referring to port d and applying the Kirchhoff's law in "Y" equivalent circuit of the QAB (in Fig. 2(a)), the equivalent link inductance of port m and n [26] is calculated as,…”

Solid-State Transformers: Fundamentals, Topologies, Applications, and Future Challenges

“…An SST base micro-grid structure is presented in Figure 9. A quad-active-bridge (QAB) converter is proposed in the paper [75] as the fundamental component of an MMC-based SST for integrating DER and distributed energy storage systems (DESS) in the distribution grid. The DC link in SST eliminates certain frequency and phase requirements, which were fundamental in AC while integrating.…”