Cost-based droop scheme with lower generation costs for microgrids

In an autonomous microgrid where centralized management and communication links are not viable, droop control has been the preferred scheme for power sharing among distributed generators (DGs). At present, although many droop variations have been proposed to achieve proportional power sharing based on the DG kVA ratings. Other operating characteristics like generation costs, efficiencies and emission penalties at different loadings have not been considered. This makes existing droop schemes not too well-suited for standalone microgrids without central management system, where different types of DGs usually exist. As an alternative, this paper proposes a cost-based droop scheme, whose objective is to reduce a generation cost realized with various DG operating characteristics taken into consideration. The proposed droop scheme therefore retains all advantages of the traditional droop schemes, while at the same time keep its generation cost low. These findings have been validated through simulation and scaled down lab experiment.