Generation cost minimization based distributed coordination control in DC microgrids

This paper develops a new fully distributed coordination control scheme for optimally reducing the total generation cost (TGC) in DC microgrids that includes different types of dispatchable distributed generations (DGs). It presents the normalized running cost as a comprehensive economical dispatching problem (EDP) solving method to overcome the drawbacks of the conventional EDP solving techniques. The proposed controller optimizes load sharing between DGs and regulates microgrid's average voltage using tertiary and secondary control levels. Through local voting protocol, the tertiary controller equalizes DGs normalized costs to schedule the output power of each DG at the optimum point while satisfying inequality constraint. Furthermore, generation-demand equality constraint could be realized by secondary control level through regulating the average voltage across the microgrid. Feasibility of the proposed controller in case of load variations, plug and play capability, and communication failures are verified by the experimental studies in a lab-scale DC microgrid.