Decentralized Coordinated Control Method of Multiple Bidirectional Converters in AC/DC Hybrid Microgrid

The AC/DC hybrid microgrid combines the advantages of AC microgrid and DC microgrid, and provides a more effective way for high-density distributed energy accessing to distribution network. The AC/DC power interface of hybrid microgrid, which is composed of multiple parallel AC/DC converters, plays a key role in maintaining the power dynamic balance of the AC and DC areas and the constant of AC side frequency and DC side voltage. For the parallel operation of multiple AC/DC converters based on the theory of adaptive inverse control with variable step size, this paper presents a decentralized coordinated control method for AC/DC converters. This method combines the advantages of droop control and adaptive inverse control. It can not only make the AC/DC converters distribute the active power in accordance with the rated capacity, but also can realize zero-error adjustment of the DC bus voltage or the AC area frequency, and obtain a better dynamic response than traditional adaptive inverse control. Finally, combined with the demonstration project of the first commercial AC/DC hybrid microgrid in China, the correctness and feasibility of the proposed control method are verified by the simulation experiment. © 2018 Automation of Electric Power Systems Press.