Coordinated control of photovoltaic hybrid energy storage hydrogen generation system based on DC-bus signaling optimized droop control

In response to the problem that the traditional droop control cannot adapt to the high-frequency and low-frequency response of the hybrid energy storage system (HESS) and the excessive bus voltage fluctuations when the PV power changes, a coordinated control strategy based on the DC-bus signaling (DBS) is proposed. Firstly, the mathematical model of the photovoltaic hybrid energy storage hydrogen production system is established. The control strategies for each unit under different operating conditions are proposed. Secondly, the system is divided into five operating modes according to the fluctuation range of DBS, and a variable coefficient droop control strategy is designed. This enables HESS to reduce the steady-state voltage deviation while lowering the bus voltage fluctuations. Then, considering the controllable regulation characteristics of the electrolyzer power, an energy management strategy (EMS) is designed to achieve power balance and stability of the system. Finally, using the MATLAB/Simulink simulation software, experiments are conducted with different solar irradiance settings to verify the effectiveness and superiority of the proposed control strategy.