A Flexible Power Control Strategy for Hybrid AC/DC Zones of Shipboard Power System With Distributed Energy Storages

The use of integrated shipboard power system (SPS) has greatly contributed to the next-generation vessels development. In this sense, how to realize the reasonable power distribution between hybrid zones in SPS is becoming one of the key problems to ensure system robustness and reliability. In this paper, a flexible power control strategy is proposed for the coordinated operation of the hybrid ac/dc zones in SPS. First, the interactive relationship of the ac/dc interface is analyzed, and the virtual inertia and capacitance are defined to reveal the interactive influence of the ac and the dc subgrids, which leads to a new V-f droop principle. Then, the flexible control strategy is designed based on the droop principle as well as the characteristics of the analogous virtual synchronous generator, and the key parameters' determination are discussed in detail, which can realize a proper assignment of cross-zone supportive power and improve the system dynamic response. In addition, the coordinated control loops are designed with the distributed energy storages and interlinking converters for the implementation of the strategy. Finally, the proposed strategy is validated by the simulation, which shows that the strategy can enhance the power quality and dynamics of the hybrid zones and contribute to the robustness of the whole SPS.