Energy management system strategy of DC microgrids with integration of renewable energy sources and energy storages

Abstract

Inevitable problems in DC microgrids exist including system control, prioritization of system units utilization, system net power decomposition, etc. Therefore, energy management system (EMS) strategy is required. Various EMS strategies are proposed in this thesis. Firstly, distributed EMS is proposed. The advantages and detail operations of distributed EMS are elaborated. Secondly, multi-level EMS is proposed to improve control accuracy and system reliability. Thirdly, depth of discharge and capacity setting for battery energy storages are proposed to minimize system operation cost. The next topic is related to hybridization of energy storages. System net power decomposition based on system net power frequency is proposed. Lastly, EMS with real-time economic dispatched based on comparison of system components marginal costs is proposed. Several system control algorithms are verified with MATLAB simulation. Experiment case studies are also performed to verify the feasibility and effectiveness of the proposed EMS strategies in a lab-scale DC microgrid.