Analysis of a PEM fuel cell system dynamic response (operational and simulation results)

The paper below presents an analysis of the dynamic response of a low pressure proton exchange membrane (PEM) fuel cell stack to step load changes, which are characteristic of standalone fuel cell system applications. The goal is a better understanding of the electrical behavior of the FC, as a result of the electrochemical processes, via the cell´s voltage characteristic during transient response. While changing the load, the performance of significant parameters affected such as Temperature, Pressure, Purge status etc are registered and evaluated. The analysis and experiment are based on a low pressure 1.2 kW PEM fuel cell stack (NEXAS power module). Secondly, the experiment above is simulated using Matlab/Simulink tools, while power conditioning units (PCU) are added in order to control power flow for enhanced performance. Finally, both operational and simulation data are compared to each other showing that simple PCUs applications can improve system´s efficiency. The experimental results obtained with the 1.2 kW PEM fuel cell confirm the relative slow response of this device, making the use of PCU and backup power source, such as a battery or supercapacitor, essential in order to operate with high dynamics.