A hierarchical control framework for PV-storage-hydrogen DC microgrids under varying conditions

To address challenges such as internal power balance, voltage stability, and hydrogen storage tank capacity in photovoltaic-storage DC microgrid systems, this paper proposes a hierarchical control strategy that accounts for varying power command demands under different operating conditions. A simulation model of the PV-storage-hydrogen DC microgrid is constructed with the goal of enhancing system stability and achieving smooth mode transitions. On the one hand, the hierarchical control coordinates between the command layer and power demand layer using bus voltage as a key indicator to ensure system stability. On the other hand, the system operating conditions are categorized into eight distinct modes. A multi-power coordinated control strategy is then employed to maintain stable operation, enable rapid and smooth transitions between modes, and keep the hydrogen storage tank capacity within acceptable limits. The proposed model is implemented in MATLAB/Simulink and tested under various scenarios, including sudden load changes, fuel cell operation, and stochastic photovoltaic power fluctuations. Comparative analysis of system overshoot under different control strategies demonstrates that the proposed approach significantly enhances voltage stability. Simulation results confirm the effectiveness and adaptability of the proposed model and control strategy.