Consensus-based Distributed Cooperative Control for Microgrid Voltage Regulation and Reactive Power Sharing

The centralized hierarchical control strategy has recently drawn much attention from researchers in the microgrid area. Primary control deals with power sharing among distributed generators (DGs). Secondary control is responsible for restoring the voltage and frequency back to their nominal values. However, there are two factors that presently limit the implementation of existing hierarchical control in a microgrid. First, the accuracy of reactive power sharing is low due to the difference in each DG's terminal voltage. Second, centralized high-bandwidth communication infrastructure is required, which is expensive and fragile, especially with high penetration of DGs. This paper presents a distributed cooperative control framework, which not only regulate the voltage at the critical bus, but also realize accurate reactive power sharing among DGs, using sparse communication with significantly lower bandwidth requirement. The proposed method is adaptive to network topology changes which supports the plug-and-play feature of microgrid. Performance of the proposed control is demonstrated through simulation results on a 4-bus microgrid testbed.