  Distributed secondary control plays an important role in DC microgrids, since
it ensures system control objectives, which are power sharing and DC bus
voltage stability. Previous studies have suggested using a control architecture
that utilizes a parallel secondary bus voltage and current sharing
compensation. However, the parallel controllers have a mutual impact on each
other, which degrades the transient performance of the system. This paper
reports on an alternative distributed secondary control architecture and
controller design process, based on small signal analysis to alleviate the
mutual effect of the current sharing and bus voltage compensation, and to
improve the transient response of the system. Experimental results confirm the
improved transient performance in the current sharing control and DC bus
voltage stability utilizing the proposed control architecture.
