A decentralized self-optimizing control strategy for islanded microgrid is proposed

which is capable of realizing three-level hierarchical control of the system without microgrid centralized controller and communication system

that is the decentralized primary control (DPC)

the decentralized secondary control (DSC) and the decentralized tertiary control (DTC). DPC uses the traditional linear droop control strategy to maintain microgrid the good linear dynamic performance

DSC makes each distributed generator (DG) participate in system frequency regulation directly only by their output frequency information so that the microgrid frequency can be restored within the permitted range

and DTC uses the nonlinear droop control strategy considering the generator cost to make each DG meet the equal incremental principle in order to realize the optimal operation of microgrid. In addition

the low-pass filters with different time constant are designed to decouple the microgrid dynamically to meet the requirements for both static and dynamic characteristic of microgrid. In the end

the effectiveness of the proposed control strategy is verified by a simulation example. This work is supported by National High Technology Research and Development Program of China (863 Program) (No. 2015AA050202) and National Natural Science Foundation of China (No. 51177146).