An Improved Distributed Economic Control Strategy in Combination with Unitized Regenerative Fuel Cell Stack

Hydrogen energy storage is characterized by high energy density and high capacity. Unitized regenerative fuel cell (URFC) stack is a more integrated hydrogen storage system but is still less reported in distributed DC microgrids. Its combination with electrical energy storage has a large potential in island microgrid applications. Economic dispatch (ED) is an important issue for islanded microgrids composed of distributed generation units (DGs) with different generation costs and capacities. In this paper, an improved distributed economic control strategy capable of voltage restoration is proposed to improve DC microgrid reliability and power quality. The proposed method is based on the incremental cost (IC) consensus distributed algorithm, which equals the theory that the lowest cost of the whole system can be obtained only if the IC of all the generating units is equal. In addition, one of the nodes is designed for high-quality voltage recovery. Power capacity constraints also need to be considered. Thus, in the proposed method, the node used to realize the voltage recovery can transfer the function to other power sources after reaching the capacity constraint; while the other nodes can be directly excised from the communication network. The simulation model and control strategies are implemented in Simulink software for validation.