Voltage Segment Coordinated Control Strategy for Isolated DC Microgrid with Multiple Energy Storage Units

This paper investigates the voltage segment coordinated control scheme of wind/pv hybrid isolated dc microgrid with multiple energy storage units. Firstly, the ring topology is adopted with more flexibility and higher reliability, compared with radiant topology. Then three different operation modes are proposed, that is energy storage voltage regulation mode, wind/pv power reduction mode, and load shedding mode. According to the regulation of dc voltage operating range, the voltage segment coordinated control strategy is proposed, to ensure battery energy storage units, wind/pv hybrid power generation unit and loads are all involved in the coordinated control. These terminals can adjust the dc voltage automatically according to their priorities. For multiple energy storage units, droop coefficients of droop control are adjusted dynamically based on loads power share and converters capacity. In addition, control methods of various side converters in each voltage segment are studied to meet different operation modes. Finally, simulation results show that the dc microgrid power balance is maintained automatically under different conditions such as variations of wind power generation, photovoltaic power generation, loads and energy storage capacity. The control strategy can be extended to other distributed power-based dc microgrids. Finally, the proposed control is validated by simulations using MATLAB/Simulink. The effectiveness and feasibility of the voltage segment control strategy for the proposed wind/pv hybrid isolated dc microgrid are verified.