Virtual Capacitor Concept for Computationally Efficient and Flexible Real-Time MMC Model

Published by Christine Hassoun on

STEFAN MILOVANOVIĆ(1), (Member, IEEE), MIN LUO(2), (Member, IEEE),
AND DRAŽEN DUJIĆ(1), (Senior Member, IEEE)
(1)Power Electronics Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
(2)Plexim GmbH, 8005 Zürich, Switzerland
Corresponding author: Stefan Milovanović (


This paper demonstrates the splitting of the modular multilevel converter real-time simulation model into several independent parts through the use of the virtual capacitor concept. As a result, the number of state-space matrices the real-time solver needs to take into account gets significantly reduced, offering the possibility for substantial reduction of the simulation step size. Consequently, real-time simulation quality increases. The proposed concept was verified on a large-scale hardware-in-the-loop system comprising seven RT Boxes, where the model of the physical system is deployed, and ABB PEC800 industrial controller, where control algorithms of the real power hardware are deployed and executed.


This work was supported in part by the Shift2Rail Joint Undertaking under the European Union’s Horizon 2020 Research and Innovation Program under Agreement 881772 (FUNDRES Project), and in part by the Swiss Innovation Agency—Innosuisse (as the innovation project) under Grant 38041.1 IP-ENG.


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