Master-Slave Based Hierarchical Control for a Small Power DC-Distributed Microgrid System with a Storage Device

In this paper, we analyze one of the main drawbacks of droop control-based DC microgrid systems, and propose a novel control method to overcome this problem. Typically, DC microgrid systems use droop control techniques to enable communication independency and expandability. However, as these advantages are based on bus quality and regulation abandonment, droop-based schemes have limitations in terms of high bus impedance and bus regulation. This paper proposes a novel master-slave based hierarchical control technique for a DC distribution system, in which a DC bus signaling method is used to overcome the communication dependency and the expandability limitations of conventional master-slave control methods. The concept and design considerations of the proposed control method are presented, and a 1 kW simulation under a Powersim (PSIM) environment and hardware prototype-built to verify the system-is described.