Modelling and simulation of a fuel cell unit connected via power electronic interface

A fuel cell (FC) unit is an electric generator that does not have environmental problems compared to conventional power plants producing huge mass of pollutants which stems from steam boilers. Therefore, it is one of the cleanest and most efficient technologies. In a FC, energy is not generated by combustion and generated by an electrochemical process. In this paper, modelling and simulation of a grid-connected Solid Oxide Fuel Cell (SOFC) unit is presented. The output voltage of the FC unit varies by load changes and its DC link voltage is stabilized by a DC-DC boost converter. A full-bridge three-phase inverter is also used to convert the output DC voltage to AC voltage. The linear model of power electronic converters are used to control the effects of load changes and reference power variations. Since the inverter is connected to the grid, the inverter control method is based on the Grid-following mode. The simulation results in MATLAB/ SIMULINK software validates the presented modelling and control strategy in the load and power reference change scenarios; so that the DC link voltage always remains constant and AC voltage of the inverter output also keeps its synchronism with the grid. The FC unit is able to inj ect generating power into the grid in addition to providing its local load.