DYNAMIC BEHAVIORAL MODEL OF A PEM FUEL CELL

DYNAMIC BEHAVIORAL MODEL OF A PEM FUEL CELL - Alexis Kwasinski EE 394 J-10 Distributed Generation Technologies Final Presentation

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.

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.

Physical Model - Equations Ec = Er – vact – vohm – vconc

Physical Model

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.

Behavioral Model

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

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.