A control-oriented dynamic model of proton exchange membrane fuel cells (PEMFCs) has been developed in this paper. It aims to generate system dynamics with real-time performance for the micro-chip controller design. A unified bond graph approach was employed that integrates physical and chemical domains in the fuel cell operation, including fluid dynamics, heat transfer, and electrochemistry effects. In this paper, two major bond graphs, one for thermofluids, the other for the electrochemical system, were constructed. They are inter-connected to interpret the highly nonlinear transport and reaction system dynamics. The nonlinear simulation on a personal computer (PC) is about four times faster than the realistic operation. A step response test shows that the start-up time of an example PEMFC is about 5 s from ambient conditions. Further frequency-response test in the operation region shows that the bandwidth is near 2 rad/s.
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