Distribution voltage control for DC microgrid by converters of energy storages considering the stored energy

DC microgrid is an appropriate system to interconnect dc output sources and to supply high quality power. This paper describes a novel dc distribution voltage control for dc microgrid. We assumed two electric double layer capacitor (EDLC) banks connected to a dc grid through dc/dc converters, and each EDLC converter controls dc distribution voltage when the system disconnects from the utility grid (intentional islanding operation). In previous study, gain-scheduling control that changes feedback gain according to the output power was proposed to share the output powers. We propose a new voltage control that combines fuzzy control in addition to the gain-scheduling control in order to manage the stored energy. Simulation results demonstrated the proposed method accomplished the dc voltage regulation control and the energy balancing control simultaneously.