Multi-domain Physics-Based Modeling and Control Strategies of a Microgrid Under Varying Load Conditions

To enhance renewable energy utilization and ensure a stable power supply, this paper proposes a multi-domain mechanistic modeling method for microgrids that integrates photovoltaic generation with hydrogen fuel cells, along with coordinated multi-energy management control strategies. In conditions of sufficient solar irradiance, the PV system maximizes its output through maximum power point tracking (MPPT), while the fuel cell dynamically compensates for any power deficit. During low irradiance periods, the system automatically shifts to a fuel-cell-dominated operation mode. The hydrogen fuel cell system, which consists of a fuel cell stack, gas supply unit, and cooling module, adopts a multi-domain modeling approach. It controls the output power by adjusting the gas supply, keeps an appropriate operating temperature via the cooling system, and generates hydrogen through the electrolyzer and stores it in the hydrogen tank for a continuous hydrogen supply to the fuel cell. Both the PV and fuel cell subsystems are independently modeled and validated to ensure accuracy and modularity. Once the subsystems are confirmed to perform as expected, they are integrated into a unified hybrid energy system. This integrated model is then subjected to system-level co-simulation under variable load conditions, enabling evaluation of the combined PV-fuel cell system's overall performance, coordination strategy, and dynamic response. The simulation results demonstrate that the proposed multi-domain modeling and control approach for the microgrid exhibits robust power response capability and effective energy management performance, significantly improving overall energy efficiency and operational stability.