1. DYNAMIC BEHAVIORAL MODEL OF A PEM FUEL CELL - Alexis Kwasinski EE394J-10 Distributed Generation Technologies Final Presentation

2. Introduction Goals: - Develop a Dynamic Behavioral Model of a PEM Fuel cell. Characteristics - Model studies the response of the fuel cell when the electrical load changes. - Model represents the result of the physical process rather than the process itself. - Simulations are an inexpensive and insightful tool to study complex systems.

3. Introduction Literature review: [1]“Fuel Cell Technology Handbook,” ed. By G. Hoogers, CRC Press LLC, Boca raton, Florida, 2003. [2] J.C. Amphlet, R. F. Mann, B. A. Peppley, P. R. Roberge, and A. Rodrigues, “A practical PEM fuel cell model for simulating vehicle power sources,” in Proc. Of Tenth Annual Battery Conference on Applications and Advances, pp. 221-226, jan. 1995. [5]J. T. Pukrushpan, H. Peng and A. G. Stefanopoulou, “Simulation and analysis of transient fuel cell system performance based on a dynamic reactant flow model,” in Proc. 2002 ASME International Mechanical Engineering Congress and Exposition, pp. 1- 12, Nov 2002. [7]P. Famouri, and R. S. Gemmen, “Electrochemical circuit model of a PEM fuel cell,” in Proc. 2003 IEEE Power Engineering Society General Meeting, vol. 3, pp. 13-17, July 2003.

4. Physical Model - Equations E c = E r – v act – v ohm – v conc

5. Physical Model

6. Behavioral Model - Equations FACT: The time constants of the pump and compressor, are much larger than the time constant of the cathode and anode. -Only system’s dynamic equations: τ is the pump and compressor time constant ~ 1 sec.

7. Behavioral Model

8. Simulation Results Fuel Cell Current Fuel Cell Output Voltage Output Power Simulation: Sudden load increase (2x). Objective V = constant

9. Conclusion A simple dynamic behavioral model was developed. The model agrees with known fuel cell behavior. A sudden load increase leads to: -Current increases with a time constant of 1 sec. -Voltage has a sudden drop to 50% value. -Power has a sudden drop and then increases with a time constant of 1 sec. The described behavior indicate potential problems in automotive and stationary applications. Solution: use batteries.