Operation and Control-Oriented Modeling of a Power Converter for Current Balancing and Stability Improvement of DC Active Distribution Networks

Future active distribution networks appear as a solution to the energy distribution challenges. In this context, dc systems show potential for reducing losses and electronic equipment costs. Power electronics is the main enabler to this initiative and strong research efforts are ongoing in order to find solutions and evaluate the benefits and requirements for the power converters to be applied in dc systems. There is evidence that bipolar dc networks are advantageous due to higher reliability and increased power transmission capability. In such a network, currents are typically unbalanced and, thus, increase feeder losses. Another challenge in dc active distribution networks is the overall voltage stability due to the presence of distributed energy resources and loads with their power electronics interfaces. This study proposes a power converter and its control principles, which is able to balance the currents in a bipolar dc network and improve its stability. Its operation principles, control-oriented modeling, and laboratory implementation are presented and verified through experiments.