Optimal Distributed Control of AC Microgrids With Coordinated Voltage Regulation and Reactive Power Sharing

In this paper, we propose an optimal distributed voltage control for grid-forming (GFM) inverters in islanded AC microgrids. An optimization problem is formulated where the distributed generator (DG) output voltage is considered as the control variable with technical constraints on voltage and reactive power output capacity and an objective function that makes a trade-off between voltage regulation and reactive power sharing. A distributed primal-dual gradient based algorithm is developed to solve the formulated optimization problem to address the challenges due to non-separable objective function, unavailable global average voltage, and globally coupled reactive power constraints. The effectiveness of the proposed optimal distributed control is validated through simulations on the 4-DG test microgrid and the modified IEEE 34-bus distribution test system, and the advantages of the proposed control over existing controls are demonstrated.