The Research On Inter-connection System Of Fuel Cell Distributed Generation

Distributed generation (DG) technology is a new developing technology and is regarded as one of the most important electrical supply because of the disadvantage of power generation and transmission in the 21st century. Being efficiency and pollution-free, Fuel cells has its special advantage, especially gained grave development in recent years and will be a commercial DG technology in the future. However, the dc is not steady generating by the fuel cells. The fuel cells must be equipped with power convertor controlling that adjust and manage the outputs of the fuel cells to attain suitably alternating current. With the widely appliance of the DG systems, the research of conversion devices and power electronics and network technology about the fuel cells becomes an important problem.Firstly, the fundamental theory of the PEMFC used in our research is discussed and the output characteristic line is deduced. The fuel cell system structure is chosen on the basis of the fuel cells'output characteristic line. This paper discusses the development of distributed generation, including the definition of distributed generation, the impact of traditional power grid with DG, and standard of grid-connected by IEEE, etc. For the special requirements of the DC / DC converter in the fuel cell power generation system, Boost converter which is used as the former class of 6kW proton exchange membrane fuel cell power generation system is proposed. And then a variety of converter control method is compared, the sliding mode control method for converter control is chosen in this paper. The condition of fuel cells as distributed generation connecting power grid is researched, the goal of the current control is introduced. The design method of decoupling hysteresis control strategy for active and reactive power is emphatically given under the rotating coordinate system through the analysis of three-phase inverter's mathematical models. By reasonably selecting the power control loop, current control loop, as well as the isolation transformer, a stable and good dynamic performance and network inverter device are realized. At last, in the simulation environment of Matlab/Simulink a grid-connected model for fuel cells with capacity of 6kW is built to validate the systemic topological structure and control method. Simulation results show that the proposed approach is correct and effective.