Abstract: Hydrogen production from photovoltaic (PV) power generation is an important means to improve the consumption of renewable energy and reduce the impact on the power grid. In order to suppress the power fluctuation of PV and loads in the electric-hydrogen system and reduce the change of hydrogen storage state of hydrogen storage, and to avoid the frequent start-stop of hydrogen storage equipment due to the hydrogen storage state overrun, an electric-hydrogen cou-pled DC microgrid power cooperative control strategy is proposed. First, a fuzzy control algorithm is used to optimize and regulate the power allocation of hydrogen storage and lithium battery storage. Second, the DC microgrid operating conditions are divided into normal and extreme conditions according to the hydrogen storage state, and the hydrogen storage state of the hydro-gen storage tank is dynamically adjusted by combining the proposed hydrogen storage variable-parameter sag control strategy, so as to inhibit the speed of the hydrogen storage SoH moving towards the overcharge and over discharge intervals through the different control strategies, and to improve the regulation capability of the DC microgrid. Finally, it is verified in MATLAB/Simulink that the proposed control strategy can enhance the ability of the electro-hydrogen coupled DC microgrid to suppress the source load fluctuation, maintain the stability of the DC bus voltage, and improve the problem of overcharging and over-discharging of the hydrogen storage energy, so as to enhance the service life of the equipment.

Key words: electrohydrogen coupling, direct current microgrid, fuzzy control, power coordination, sag control