陽毅平臺灣大學：機械工程學研究所劉明皓Liu, Ming-HaoMing-HaoLiu2007-11-282018-06-282007-11-282018-06-282006http://ntur.lib.ntu.edu.tw//handle/246246/61267本論文根據燃料電池之電化學反應動態模型，將一小功率的燃料電池簡化為一多輸入、多輸出之藕和系統。在不同的操作點，以疑似白色二值信號為輸入，使用線性迴歸模型對系統進行識別，嚐試使用固定參數模型，以及運用最小平方法所得的時變參數模型，以期找出能描述燃料電池系統動態的模型。 識別結果發現，使用固定參數並無法合宜描述系統動態，而以最小平方法所計算出的時變參數模型可以精準地描述系統動態。並且證實了系統動態在35至45度間變化非常小。同時發現當氫氣化學劑量超過1.2時，快速的改變氫氣流量，對燃料電池系統的電壓及電流並不造成影響。Based on electro-chemical reactions, the small-power fuel cell system is simplified as a coupled multi-input and multi-output system. Utilizing the pseudo random binary sequence as the input and ARMAX as the model, system identification is performed at different operating points. Both fixed-valued parameters and time-varying parameters are used in ARMAX in order to find a suitable model. According to the identification result, ARMAX models with fixed-valued parameters can not describe the system dynamics suitably, while models with time-varying parameters can. System dynamics are also proven to be insensitive to temperature changes between 35 and 45°C. It is also shown that when the hydrogen stoichiometry is over 1.2, fast changes of the hydrogen flow rate does no influence on the fuel cell system performance.誌謝 i 中文摘要 ii Abstract iii Nomenclature iv Abbreviations vi 1 Introduction 1 1.1 Background 1 1.1.1 History and Future 1 1.1.2 Basic Principles of Fuel Cells 3 1.1.3 Fuel Cell Types 4 1.2 Literature Review 8 1.3 The Objective and Scope of This Work 12 2 PEM Fuel Cells Characteristics 13 2.1 Overview 13 2.2 The Structure and Working Principles of PEMFCs 14 2.3 Performance 16 2.3.1 Open Circuit Voltage (OCV) 16 2.3.2 Efficiency 17 2.3.3 Polarization Curve and Irreversibilities 18 2.4 The Mathematical Model of PEM Fuel Cells 22 2.4.1 Overview 22 2.4.2 Basic Assumptions 22 2.4.3 Cathode Gas Diffusion Model 23 2.4.4 Cathode Kinetics 24 2.4.5 Internal Resistance 25 2.4.6 Block diagram of fuel cell dynamics 25 3 Identification of a Fuel Cell System: Theory & Method 28 3.1 Fuel Cell System 28 3.2 Brief Introduction of System Identification 29 3.3 Identification Procedure 30 3.3.1 Experimental design and equipment: 30 3.3.2 Selection of data set: 31 3.3.3 Data processing: 32 3.3.4 Structure determination: 32 3.3.5 Model selection: 33 3.3.6 Model evaluation: 34 3.4 Input Signal for System Identification 35 3.4.1 Input signal requirements 35 3.4.2 Brief introduction of PRBS 36 3.4.3 PRBS parameters 37 3.4.4 PRBS selection 39 3.5 Identification Region Determination 40 3.5.1 Flow Rate Experiments 40 3.5.2 Humidity Experiments 41 3.5.3 Temperature Experiments 42 4 Results and Discussion 43 4.1 Temperature effects on performance 43 4.2 Flow stoichiometry effects on performance 46 4.3 Humidification effects on performance 54 4.4 Identification Results of 55 4.4.1 Inputs and Outputs of plant 55 4.4.2 Identification Results of for Different Loads 57 4.4.3 Identification of for Different Temperatures 71 4.5 Identification Results of 74 4.5.1 Inputs and Outputs of plant 74 4.5.2 Problems of Identification for Fixed Voltage Case 75 4.6 Identification Results of and 76 4.7 Discussion and Summary 79 5 Conclusion and Future Work 81 5.1 Conclusion 81 5.2 Future Work 81 6 Reference 83884857 bytesapplication/pdfen-US質子交換膜燃料電池燃料電池系統識別疑似白色二值信號線性迴歸模型proton exchange membrane fuel cellPEMsystem identificationPRBSARMAXthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/61267/1/ntu-95-R93522803-1.pdf