Humidification Control System Research

In the past decades, with fossil energy being quickly consumed, the utilization of clean energy has become a hot topic. For its high-efficiency, energy-saving and environment-friendly features, proton exchange membrane fuel cell(PEMFC) attractes widespread attention. Humidity is a significant operating parameter in the operation process of fuel cell. So the influence of humidity on the working performance of fuel cell cannot be ignored. In this thesis, anode humidification temperature is under control and other operating parameters are fixed in order to adjust the humidity of PEMFC and improve its working performance.The bubbling method is chosen to accomplish the humidification of reaction gas in the laboratory testing environment for the purpose of adjusting humidity of fuel cell by analyzing the humidity characteristics of PEMFC.The relative humidity in anode and cathode has much influence on the working performance of PEMFC. Then fuel cell is divided into inlet, center and outlet parts according to the internal structure of fuel cell and the relationship between temperature and humidity. The internal humidity condition of PEMFC is judged by analyzing the average individual cell voltage of these three parts. Then individual cell voltage monitor system and temperature acquisition circuit are designed to meet the requirements of humidification control system. And the analysis of the measured individual cell voltage data proves the previous judgment method.Based on the humidity characteristics of PEMFC, fuzzy neural network(FNN) control algorithm is used in the humidification system. On the basis of the relationship of the average individual cell voltage among these three parts, fuzzy rules are established and applied to the neural network structure so as to control the anode humidification temperature for the purpose of improving its working performance.Finally, the designed humidification control system is applied to the actual testing process. And the results show that the designed system has good control effect by analyzing the experiments data.