Secondary control in AC microgrids challenges and solutions

The hierarchical control structure of a microgrid can be described as consisting of four levels: processing, sensing and adjusting, monitoring and supervising, and maintenance and optimizing. This paper focuses on the secondary control level, which can be classified as centralized or decentralized control. A comprehensive investigation of both centralized and decentralized control is presented in this paper. Decentralized control is proposed in order to deal with some of the disadvantages of central control, such as the high risk of unplanned interruption arising from a Microgrid Central Controller (MGCC) malfunction. However, decentralized control is not yet complete, and some challenges to its implementation remain. This paper also looks at these challenges and proposes some solutions that may help to improve the performance of decentralized control and overcome its disadvantages. Finally, a general methodology of microgrid control is modeled.