A unified distributed control scheme on cost optimization for hybrid AC/DC microgrid

This paper presents a unified distributed control scheme for hybrid AC/DC microgrid to realize the economic operation of system. The existing researches on distributed optimization are purely focused on the DC or AC microgrid environment, and the research on the economic optimization of hybrid microgrid containing AC and DC subgrid has not been further studied. In this paper, a unified distributed optimization strategy for hybrid microgrid based on the equal incremental cost(IC) principle is proposed. The control strategy proposed in this paper can be divided into two parts. For the first part, ICs of the sources reach consensus through the distributed protocol in a single AC subgrid or DC subgrid, and the average voltage recovery is achieved by building a voltage observer in every source. For the second part, by using PI controller, the reference power of the bidirectional dc-ac interlinking converter is easily defined and the global incremental costs are finally equalized according to the respective distributed protocols. Thus the generation cost is optimized. Feasibility and effectiveness of proposed method are verified by simulation in Matlab/Simulink environment.