| Because resource is consumed rapidly and environment is polluted seriously, fuel cells with high efficiency and non-pollution have become important task, which solve energy crisis in 21th century. Solid oxide fuel cell (SOFC) is one of the most popular fuel cells in current studies. Its operating temperature is 600-1000°C, and can provide remaining heat with good quality. It is able to operate with fuel containing CO, and does not need costly metal catalyst and special fuel preprocessing. SOFC has the advantages of sulfur tolerance, non corrosiveness, high thermoelectricity efficiency etc. It is more suitable for establishing large scale industry thermoelectric power stations.With the maturation of the SOFC technique, during the process of operation, SOFC performance should be improved and guaranteed powerfully. At the present time, its research is mainly focused on the mechanism model, structure and material at home and abroad. It is well known that the SOFC system is sealed, and works in a complicated high-temperature environment. It is very difficult to measure the interior states of the SOFC, and the experimental analysis is very expensive and sometimes infeasible. Compared with the experimental research, numerical analysis and simulations are cheaper and easily done. An important tool in the fuel cell development is mathematical modeling, which has the capability of predicting the fuel cell performance. In virtue of the mathematical models, the researchers can predict, simulate and analyze the SOFC performance in the operating range and different transient states. So, we firstly go on static and dynamic modeling and numerical simulations for the SOFC based on the advanced identification techniques. The control design should be emphasized besides those. Reliability and security of the SOFC should be guaranteed via the high performance control system. Based on the established dynamic models of the SOFC, some control schemes are developed in this thesis. The control purpose is that the fuel utilization and output voltage of the SOFC are kept stable for DC type loads under conditions of load fluctuations. Furthermore, the SOFC should run in a safe and high efficiency environment, which is favorable to prolong its lifetime. However, the aspects are very weak junctures in the SOFC development. Consequently, there are many things to do for the control-oriented models and the control strategies of the SOFC deeply.The main contributions and achievements of this thesis are summarized as follows:1. The output characteristics of the SOFC are analyzed and summarized. Qualitative analysis is made for the factors which affect the output characteristics of the SOFC. In the thesis, qualitative analysis is made from two aspects: one is from material and construction parameters. Another is from operating parameters which include temperature, pressure of anode and cathode, fuel composition, oxidant composition, hydrogen flow rate, fuel utilization, etc. The main aim of this thesis is how to improve the output characteristics of the SOFC by regulating the operating parameters. However, the factors for material, construction design and so on will not be considered. In addition, a kind of equivalent circuit and a steady-state feasible operating area of the SOFC are also simply analyzed in the thesis, respectively.2. Design and set up a SOFC steady-state mathematical model.Make a numerical simulation of SOFC affecting Factors as internal temperature, gas flow rate and concentration distribution .3. Designe and set up a dynamic mathematical model of SOFC.Make a numerical simulation for dynamic mathematical model of planar anode-supported solid oxid fuel cell. |
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