Triple Active Bridge Based Multiport Energy Router for Subsea – Renewable Interconnection
Arnur Karbozov, Mriganka Ghosh Majumder, Harish S. Krishnamoorthy, Kaushik Rajashekara
Abstract
In order to supply reliable power to the subsea loads at high system efficiency and low emissions, there is a growing interest in employing offshore renewable resources close to the point of use. However, such system has predominantly stayed in the conceptual stage so far. Hence, there is a need to develop methodologies for interconnecting multiple renewable sources with offshore loads. This article proposes a Multiport Energy Router (MER) based on a Medium Frequency (MF) Solid-State Transformer (SST) that integrates renewable energy sources (RES) and Energy Storage Systems (ESS) to supply clean energy for subsea loads. The MER forms a three-port network, where HVDC Wind Turbine Generator (WTG) power system and MVDC ESS are interfaced with subsea loads. The MER is realized by series-parallel combination of Triple Active Bridge (TAB) converters. The TAB modules are critical to enhance the power density, fault-tolerance, and efficiency of the proposed system. In this article, a novel simple algorithm for extending soft-switching region of TAB by selecting optimal control variables is proposed. Moreover, this article presents a control strategy for the MER, which addresses the DC-link voltage imbalance issue for each of the cascaded TAB converters. The simulation and the Hardware-in-the-Loop (HIL) results based on Typhoon-HIL system are presented to verify the proposed converter operation and the control strategy.