17. Leader-Distributed Follower-Decentralized Control Strategy for Economic Dispatch

In this chapter, we introduce a leader-distributed follower-decentralized (LDFD) control strategy for series–parallel microgrids (SPMGs) in the islanded mode, under which the economic dispatch (ED) is achieved with voltage quality guaranteed and frequency synchronization. In this control strategy, a distributed control method is presented for the leader of distributed generators (DGs) and an improved droop control method is designed for other DGs (followers) to optimize the generation cost and frequency control of the system. Furthermore, a unified voltage regulator is proposed to make the power factor of each DG in the same string equal. Since only the leader in each string communicates with its neighboring leaders with low data transfer rate, very sparse low-bandwidth communication networks are needed in this scheme, which reduces costs and increases the reliability in the event of a communication failure. In addition, the small-signal stability of the system is analyzed and the design of the related parameters is given. Some cases are designed to evaluate the performance of the strategy, and the simulation results verify the effectiveness of the proposed method.