Performance Test of 1 kW PEM Fuel Cell System to Determine Its Empirical Model

Abstract

The proton exchange membrane fuel cell (PEMFC) has a higher power density, so it is suitable to be utilized for powering electric vehicles (EVs) and supporting the grid's power balance and voltage stability. As its load will vary during operation, the PEMFC system have to manage the fuel feed following load variations. In this study, a dead-end anode-type PEMFC system with a rated power of 1 kW is used to investigate its performance under current loading rates of 0-28 A in steady-state conditions. From the test results, the empirical models were derived and simulated in MATLAB. The test is conducted by measuring the PEMFC stack's current, voltage, hydrogen flow rate, and purging behavior. The experimental results show a nonlinear correlation between stack current and voltage as well as its efficiency of hydrogen consumption to the electricity generated. The hydrogen flow rate exhibits a linear relationship to the generated power output in normal operation, neglecting the purging flow rate. Meanwhile, the total consumed hydrogen, including purging process, performs an exponential result which indicates more hydrogen was consumed for purging. Moreover, the observed purging behavior shows that the load current affects the purging interval time in an exponential decay manner. Some possible control methods are then discussed to control the hydrogen flow that dynamically follow the load variation and enable a not-complete purge; thus, the hydrogen consumption could be optimized and the excess hydrogen during the purging could be minimized.