A Dynamic Model of a PEM Fuel Cell System

The steady states and dynamics of a fuel cell system are influenced by both operating conditions and the frequency characteristics of electrochemical reactions in a cell. A dynamic model of a practical fuel cell system, based on an analytical theory and empirical data, is proposed. The model consists of three parts, such as an open circuit voltage model including fuel flow and reaction in channels, an equivalent circuit model caused by voltage losses of electrochemical reactions in a cell, and an air compressor model (a fuel supply model among auxiliary systems in a fuel cell system). It will be useful to design the power system and control strategy and to analyze the system dynamics in a fuel cell power system. The model is verified by experiments of 1kW PEM FC system. The dynamics of its OCV(open circuit voltage) by fuel flow effect, and the frequency characteristics of reaction dynamics in a cell are verified by experiments.