Simulation Analysis of Grid-connected AC/DC Hybrid Microgrid

In this paper, a grid-connected AC/DC hybrid microgrid with some renewable energy sources (PV, fuel cell), energy storages and loads is proposed. The hybrid microgrid consists of both ac microgrid and dc microgrid. A bi-directional AC/DC converter is used to link the ac microgrid and dc microgrid by regulating the power between them. The dc side of the PV array and fuel cell through the DC/DC converter connected to the dc bus. A battery act as energy storage device is connected to the dc bus through the bi-directional DC/DC converter. The PV array of ac side is connected to the ac bus through the DC/DC/AC converter. The proposed hybrid microgrid operates in grid-connected mode by the ac microgrid. Then, the model and control strategy of each module are analyzed and the simulation test-bed is realized using MATLAB/Simulink. The influence of the system operation is simulated from the steady state of the system, the transient process of the switching of the fuel cell, the change of the solar irradiance in the both ac and dc sides, and the change of the AC and DC loads. Finally, the results for simulation analysis of operation characteristics and transient process of grid-connected operation under different conditions are presented with the final conclusions.