A distributed coordinated economic droop control scheme for islanded AC microgrid considering communication system

The conventional PQ droop control method is easily affected by load changes and line impedance in the islanded AC microgrid and always results in the problems in dynamic performance. Therefore, the parallel Distributed Generators (DGs) have uneven power distribution and poor economy. To solve the problem of inaccurate power distribution of DGs and low operating costs, we propose an improved economic droop control strategy based on distributed algorithm, in which the second-level optimization control is added to iteratively modify the reference voltage and frequency in the droop control. In this process, the system optimal economic operating point will also be achieved. Considering the advantages of centralized and decentralized control, the control architecture based on sparse multi-agent communication network improves the robustness and flexibility of the system because there is no central leader. Finally, simulation analysis of the islanded AC microgrid is carried out by using PSCAD/EMTDC simulation software to verify that this strategy can achieve the precise control of the tie-line power according to the load demand response, and the optimal economic operation for each DG.