Autonomous economic operation of grid connected DC microgrid

This paper presents an autonomous power sharing scheme for economic operation of grid-connected DC microgrid. Autonomous economic operation approach has already been tested for standalone AC microgrids to reduce the overall generation cost and proven a simple and easier to realize compared with the centralized management approach. In this paper, the same concept has been extended to grid-connected DC microgrid. The proposed economic droop scheme takes into consideration the power generation cost of Distributed Generators (DGs) and utility grid tariff and adaptively tunes their respective droop curves. The scheme can be realized with the local information (terminal voltages and currents) without centralized controller and high bandwidth communication links. Microgrid voltage can be maintained within the define limit (±5%), which, if required, can be restored back to the nominal value through the proposed secondary control. The performance of the proposed scheme has been verified for the example grid-connected DC microgrid.