Research On Fuel Cell And Its Hybrid Power System Used On Vehicles

Fuel cell and the hybrid power vehicles as highly prospect of new energy vehicles, has the advantages of zero emission, high efficiency, has attracted more and more attention and research all over the world.This thesis attempts to make a research of the model establishment, simulation analysis and test validation of the small hydrogen PEM (proton exchange membrane) fuel cell; and then research the structure, experiment and control strategies of fuel cell+lithium battery hybrid power system based on this model. I hope this thesis can make a contribution to our meager strength for the popularization of the fuel cell and the hybrid power system. In this paper, the main work and research results as follows:(1) This paper based on chemistry, hydromechanics, materials science, and other subjects, combined with many predecessor scholars’ experience and data the aspect of the fuel cell model establishment, taking a domestic 500W hydrogen fuel cell as the prototype, has established the semi-empirical model of the PEM fuel cell. The experiment verification of use material object to prove the accuracy and practicability of the model, the model probably can instead of material object to research the physical characteristics of fuel cell, control strategies and other aspects of fuel cell. It not only improves the work efficiency, but also saves a lot of time and money.(2) We use the established PEM fuel cell model for the simulation analysis, learning about the factors such as temperature, humidity and working pressure of the influence on the PEM fuel cell output voltage, and fitting out the efficiency diagram of the fuel cell system.(3) The thesis analyzes the fuel cell+lithium battery hybrid power system of various typologies exhaustive, and ultimately chooses the topology of DCDC converter attached directly to the fuel cell, then in paralleled with the lithium battery.(4) While the research of the fuel cell, we also research other key components of the hybrid power system such as lithium battery and DCDC converter on the physical characteristics, and fitting out the of the three dimensions efficiency MAP figure of the lithium battery and the DCDC converter.(5) The experimental research is the way indispensable, the drive motor experiment of the fuel cell single power systems, and the hybrid power system, is not only make the research work more deeply, but also the research will be in favor of usability. The experiment result shows that the advantage of the hybrid power system, its intuitive data is also enlightening the research of the control strategy.(6) Hybrid power system control strategy has been an important part of the hybrid power system, the paper analyzes the On/Off control strategy, and optimize it because of the disadvantages of On/Off control strategy. Finally, we have build out of the On/Off control strategy model and the optimized control strategy model in the Matlab/SIMULINK software, and we have compared and analyzed the two kinds of control strategy, the result shows that the optimized control strategy in fuel economy and power performance is better than that of the On/Off control strategy.