Distributed Primary and Secondary Control Strategy for Power Sharing and Voltage Restoration in a DC Microgrid

摘要

Because of having various advantages of direct current (DC) over alternating current (AC) including reduced losses and smooth integration with distributed energy sources (DERs), DC microgrids (DC MGs) increases more attention nowadays. The presence of a large number of DERs voltage support and proper power-sharing is the major problem in such a multisource DC MG. This paper discusses the problem associated with the power-sharing or current sharing accuracy between two parallely connected dc-dc boost converters in a DC microgrid. In this paper, primary and secondary control strategies for DC MGs are applied to provide good power-sharing accuracy among all converters and voltage restoration of the common DC bus. The main drawback of the conventional droop method under primary control is poor power sharing accuracy and drop in voltage of a common dc bus voltage because of droop action. The proposed average current and average voltage secondary control strategy improve the current sharing accuracy and common dc bus voltage restoration. The simulation results and experimental analysis are validated by using the verified proposed method.