Distributed secondary control for droop-controlled autonomous microgrid

Motivated by the cooperative control theory of multi-agent systems, we study the distributed secondary voltage and frequency control problem in a lossy droop-controlled autonomous microgrid. At first, a distributed cooperative control algorithms is designed to synchronize the voltage of each generation unit to the reference value in finite time. We then provide a frequency control protocol and present the sufficient condition for phase angle cohesiveness and frequency synchronization of generic lossy microgrids. In addition, we present a selection of controller gains and set-points leading to a desired active power sharing among the generation units. The analysis is validated via a simulation example.