Cost-Based Droop Scheme for DC Microgrid

DC microgrids are gaining interest due to higher efficiencies of DC distribution compared with AC. The benefits of DC systems have been widely researched for data centers, IT facilities and residential applications. The research focus, however, has been more on system architecture and optimal voltage level, less on optimized operation and control of generation sources. The latter theme is perused in this paper, where cost-based droop scheme is proposed for distributed generators (DGs) in DC microgrids. Unlike traditional proportional power sharing based droop scheme, the proposed scheme considers the generation costs of DGs and dynamically tunes their droop gradients to produce more power from less costly DGs and vice versa. The proposed scheme is fully autonomous, simple to implement in dispatchable and non-dispatchable sources coupled with storage, support islanded and grid-connected operation. Most importantly, the proposed scheme can reduce overall total generation cost in DC microgrids without centralized controller and communication links. The performance of the proposed scheme has been verified under different load conditions.