Design Of Distributed Grid-Connected Power System Based On PEMFC

As coal, petroleum and other primary energy cause serious environmental pollution, and the prices continue to rise, people begin to pay more attention to distributed generation with lower pollution, renewable energy. Compared with the centralized power supply, Distributed Generation (DG) can be distributed around the user, reduces the cost of transmission projects, but also for those of the high demand for power supply reliability, and provide electricity for remote areas. DG combined with traditional centralized power grid can save cost and improve the overall efficiency, and improve the reliability of power supply. Fuel cells, solar energy, wind energy, hydro energy, biomass energy and micro turbine are developing rapidly in recent years. Fuel cells with high efficiency, modular, no pollution, capacity, etc. has been widespread concerned, they are expected to be commercialized gradually. However, the dc output of fuel cells is unstable, therefore, it must be changed into the stable ac by using power electronic devices, and then, the fuel cells can supply power.Distributed grid-connected power system based on the Proton Exchange Membrane Fuel Cell (PEMFC) is researched in this subject, and the Nexa 1.2kW fuel cell power generation system is used for the grid-connected testing. In this paper, firstly the principle of the fuel cell power generation and classification of fuel cells in DG applications, the DG grid-connected standard IEEE 1547-2003, and the possible effects of interconnection is expounded in Chapter II. In Chapter III, fuel cell distributed generation grid-connected system is designed. DC/DC+DC/AC single inverter structure of two-stage transformation system is used, the boost DC/DC structure with voltage control is chosen for the DC converter, the DC/AC is controlled by voltage and current 2-loops with full-bridge structure, active combined with passive detecting method is used for the islanding detecting. In Chapter IV, the fuel cell distributed generation grid-connected system is modeled and simulated by using Matlab/Simulink, and the simulation results show the feasibility of this design. The experiment of grid-connected based on distributed power generation system has been done by operating on Nexa 1.2 kW fuel-cell power generation system platform, which demonstrates that the control method and the effectiveness algorithm is valid.