Investigation On The Coordinated Control And Energy Management Of DC Micro Grid

With the development of society and reform of electric industry, the need for thedevelopment of recyclable energy and distribution and intelligence is the trend of thedevelopment of power system. In this environment, DC micro grid, as a new type ofpower system, matches the current need and stands for the future development direction.Thus, attention is increasingly paid to the DC micro grid. However, compared to ACmicro grid, the control and management strategy of DC micro grid is not so developed.Thus, in this paper, research and analysis is conducted on the control and managementstrategy of DC micro grid.First, the common framework and operation characteristic is analyzed in the paper,and then the distributed generations and energy storage system are delved. Practicalmathematical model of photovoltaic cell is established based on the analysis of itsmechanism. Based on the model, MATLAB simulation model is built and outputcharacteristics of PV cell is analyzed. The mechanism and output characteristics ofbattery and fuel cell are discussed, which lay a foundation of further research.Second, the bus voltage control strategy of DC micro grid is proposed. Maximumpower point tracking of PV is then built and tested. The method introduced meaningfulvoltage deviation into the system based on the voltage droop control. By settingthresholds of micro sources, priority of micro sources are set and voltage stage arecreated. In different voltage stages, different sources are cut in or in differentoperational modes sources are running. While in the same stage, sources are controlledunder voltage droop control method or in constant current mode. The result ofsimulation analysis of the method indicates that the DC bus voltage can be controlledstably under the vibrant environment and fluctuating load power.At last, the theory and method of multi agent system are applied to the control andmanagement of DC micro grid. Multi agent based DC micro grid control strategy isproposed. A double-layer multi agent control system is established, which includesmicro grid agents and micro sources agents. Principles and paradigms of agents areformulated. Micro grid agent is in charge of controlling and coordinating source agents,while source agents are in charge of controlling micro grid sources. Simulative test isconducted in a micro grid which includes three sources and whose time scope is12hours. Real illumination and load data are included in the test. The test results verify theeffectiveness of the Multi agent based energy management strategy.