Hierarchical Coordinated Control Method for Multiload DC Microgrid Units

Electricity has become not merely a source of power but also a vital component of our lives in a rapidly changing world. However, according to a World Bank report, 17% of the globe's population live without power. The key cause for such a huge population not being electrified is the proximity of the central electrical grid system or the high expenditure of installing the grid lines to such remote areas. The notion of a microgrid was first proposed more than a decade ago, but the numerous obstacles it entails have hampered its broad adoption and made it a research focus in recent years. A hierarchical control structure of the microgrid is designed, which is divided into layers according to the control objectives and control time scales of the microgrid, and the hierarchical control structure is realized by using multiagent technology. In the framework of hierarchical control, aiming at the demand of energy coordination and optimization of the microgrid, the operation strategy of the microgrid is proposed in grid-connected and/or off-grid mode. In the grid-connected mode, the large power grid is used for power supply and in the off-grid mode, the load bidding mechanism is introduced to ensure the power supply of important loads. Experiment results reveal the power quality and stability of the system.