Electrochemical Optimization and Small-signal Analysis of Grid-connected Polymer Electrolyte Membrane (PEM) Fuel Cells for Renewable Energy Integration

In this paper, a small-signal model of a single cell Polymer Electrolyte Membrane Fuel Cell (PEMFC) was developed based on state-space approach to study the effect of various operating conditions on the dynamic responses of the fuel cell. Dynamics of hydrogen, oxygen, and water partial pressure were considered in the modeling procedure. Effect of input parameters such as inlet molecules of hydrogen, oxygen, relative humidity, temperature, and number of PEM fuel cell stack on output voltage/current was analyzed using the developed dynamic model. The transient responses of a single- and multiple cell PEMFC were also investigated as the operating parameters of air flow rate, fuel flow rate, temperature, anode/cathode relative humidity level, and electrical current were varied. Next, the studied PEMFC was integrated to the main grid using a boost DC/DC converter and a DC/AC converter. The stability of the overall system was tested through eigenvalue analysis in MATLAB, and several case studies were designed to examine the sensitivity of boost converter parameters and phase-locked loop (PLL) on the stability of the overall system. The analysis results were then validated on a 100 Watt simulated PEMFC in MATLAB Simscape Power System toolbox, and a set of optimum operating conditions were proposed.