Distributed Control Method for Economic Dispatch in Islanded Microgrids With Renewable Energy Sources

The economic dispatch in islanded microgrids (MGs) is a thorny problem due to the low equivalent inertia and the uncertainty of environmental conditions. In this paper, a two-layer model is proposed for economic dispatch in islanded MGs, in which an MG is considered as the lower layer, while a communication network is considered as the upper layer. Furthermore, a systematic method is presented to derive fully distributed control laws from any given communication network. On the communication network, there are two subgraphs, <inline-formula> <tex-math notation="LaTeX">$\tilde {G}$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">$\hat {G}$ </tex-math></inline-formula>, one of which consists of all agents, while the other of which consists of only controllable agents. Correspondingly, two sets of control laws are derived from the two subgraphs, where the control laws from the subgraph <inline-formula> <tex-math notation="LaTeX">$\tilde {G}$ </tex-math></inline-formula> ensure the supply-demand balance in the MG, while the control laws from the subgraph <inline-formula> <tex-math notation="LaTeX">$\hat {G}$ </tex-math></inline-formula> realize the economic dispatch. Moreover, the economic operation in MGs can be satisfied, only if agents on the communication network regulate distributed generators iteratively according to the control laws. Finally, three cases are designed to evaluate the performance of the method, and the simulation results verify the effectiveness of the proposed method.