A Differential Power Processing Interconnected Architecture for DC Microgrid Cluster

In this article, an alternative interconnected architecture for dc microgrid cluster with differential power processing (DPP) merit is proposed, which is able to effectively reduce cost and improve efficiency for system with multiple ports having a common ground. In a cluster of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> microgrids, a total of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> + 1 bidirectional dc–dc converters are employed, among which <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> power differential converters are connected in series between the microgrids and the dc bus, and the rest one is employed to connect the common ground. Hence, these converters only need to process a small portion of total power caused by the differential voltage between bus and microgrids or caused by the unbalanced currents among microgrids. Most of the power interchanging among microgrids transmits without processing through converters, which contributes to low cost and high efficiency. In the article, not only theoretical analysis of the proposed DPP interconnected architecture for dc microgrid cluster is provided in detail, but also steady-state and dynamic experimental results are demonstrated to verify its favorable merits.