Hierarchical control structure in microgrids with distributed generation: Island and grid-connected mode

The hierarchical control structure of a microgrid can be described as having four levels responsible for processing, sensing and adjusting, monitoring and supervising, and maintenance and optimization. The responsibility of the hierarchical control level is to provide control over the production of power from renewable sources. This paper comprehensively investigates the principles of hierarchical control in microgrids from a technical point of view. In the first step, this article covers the control of the power generation using two popular renewable energy sources, namely wind turbines and photovoltaics. The synchronization and power flow between the microgrid and the main network is then investigated. Finally, some research questions are presented to improve the performance of the hierarchical control, especially in the secondary decentralized control and energy storage systems.