A Hierarchical Self-Regulation Control for Economic Operation of AC/DC Hybrid Microgrid With Hydrogen Energy Storage System

The introduction of hydrogen energy storage system (HESS) as a potential form of energy storage systems (ESSs) has a significant impact on original control and operation. This paper presents a hierarchical self-regulation control method, which can be divided into the supervisory layer and local layer control. The supervisory layer control decides the output power of ESSs, according to the operation cost function so that the system can reach economic optimum during the operation process. The local layer control adopts virtual inertia control with global power support to improve system stability. First, a HESS model composed of an electrolyzer, hydrogen storage tank, and the fuel cell is established. SOCH of hydrogen tank is defined to express produced and consumed hydrogen. Then, aiming at supervisory layer control, operation cost functions of battery energy storage system (BESS) and HESS under different operation modes are built. Virtual inertia of ac ESS and virtual capacitance of dc ESS are introduced for local layer control. Finally, the simulation results based on the RT-LAB platform of both 24-h operation case and step power change case verify the correctness of the proposed method. The comparison with only droop control method shows that the proposed method can achieve the lowest operation cost and improve system inertia.