Improved digital average current sharing control strategy for DC microgrids

Abstract

DC Microgrids (MGs) are increasingly popular in recent years to support distributed generation based power systems. This paper focuses on the improvement of the load sharing control strategy and presents a decentralized control scheme, namely improved digital average current sharing (IDACS). Compared to the conventional hierarchical droop control scheme, the IDACS shows the structural difference and demonstrates the advantages of high modularity, automatic load sharing, low current deviation, and robust voltage regulation. In the proposed IDACS scheme, each primary converter includes both current controller and voltage controller to compensate voltage uniformity, which is caused by droop control scheme. Based on the foundation of digital average current sharing (DACS), a comprehensive approach is developed to design controllers for DC-DC converters by using anti-windup strategies. The improved performance is validated by simulation and demonstrates low voltage regulation and fast recovery time.