Distributed economic dispatch for energy storage units in DC microgrids with aperiodic sampled data

The increasing applications of renewable energy resources and energy storage units (ESU) raise the necessity for reliable, efficient, and economical power systems. However, the charge/discharging power loss of ESUs cannot be ignored in the islanded microgrid. This paper focuses on the economic dispatch (ED) problem of ESUs in DC microgrids to reduce charging/discharging power loss, meet the power balance requirement, and against communication delays. Specifically, the distributed cooperative control algorithm designed in this paper forces incremental costs of all ESUs to a consistent value to minimize the sum operation loss of all ESUs in the small time scale. Meanwhile, power imbalance auxiliary variables are added to the control algorithm to satisfy the power balance constraint in the control process. Moreover, the ubiquitous time delay effect of communication links on the dispatch performance is solved by presenting an aperiodic sampled data-driven control method. The control parameters are determined by solving strict linear matrix inequalities, and the system stability analysis is also presented through the Lyapunov-Krasovskii functionals. Compared with the traditional control methods, the provided algorithm can overcome the negative effect of communication delay and save 16.94% of the sum ESUs operation loss under the given scenario.