Interactive Control of Coupled Microgrids for Guaranteed System-Wide Small Signal Stability

This paper proposes an interactive control framework for microgrid interconnections to achieve effective load sharing and guaranteed system-wide small signal stability. In the proposed framework, hierarchical control is performed at three levels operating in different time frames. A model reference control-based scheme is implemented for primary level power sharing, through which the interface inverter of each microgrid is controlled to track a designed reference model. At the secondary level, an interactive droop management scheme is proposed to manage the reference model droop gains based on a distributed stability criterion. At the tertiary level, an ac power flow-based supervisory control strategy is utilized to dispatch the nominal setting to each microgrid central controller (MGCC) for the primary level reference tracking, and broadcast an interaction coefficient to each MGCC so that the droop gains can be managed to guarantee system-wide stability. Numerical analysis of a study system designed based on the IEEE 123-node test feeder demonstrates the effectiveness of the proposed interactive control framework.