Research On Fast Dynamic Response Control Strategy Of Fuel Cell In Vehicle Applications

When proton exchange membrane fuel cell is used as the power source of vehicles,it will undergo frequent load changes,which leads to a huge life difference between the vehicle applications and other uses.Therefore,it has great significance to research the voltage response behavior of fuel cell and improve it’s response ability under varying load,to prolong the life of fuel cell in vehicle applications and promot the commercial development of fuel cell vehicles.This paper focuses on the dynamic response of fuel cells.The main contents are as follows:Firstly,this paper describes the composition and working principle of PEMFC,and analyzes the main voltage losses that affect the output voltage of PEMFC.Based on the above factors,the output voltage model of PEMFC is established.With this model,the steady and dynamic processes of the actual fuel cell are researched and compared with the actual voltage response curve,which verifies the reliability of the model.Secondly,this paper designs and builds a fuel cell test system,combined with physical testing and output voltage model,to study the effects of different operating parameters on the dynamic voltage response of fuel cell.On this basis,this thesis deeply studies the dynamic voltage response curve and finds that gas shortage is the main reason for the poor dynamic response.Therefore,according to the level of gas shortage phenomenon,the dynamic response state of the fuel cell is divided into different states.There are three states,non-gas shortage,partial gas shortage and overall gas shortage,and the boundaries between each state are determined.In addition,this paper also analyzes the specific meaning of the gas transmission stage and the hydration stage of the dynamic response process and summarizes the formulas of the voltage response characteristic parameters.Finally,in order to avoid the harm of gas shortage on fuel cells’ life,based on the basic principle and design method of fuzzy control,this paper designs a dynamic gas supply strategy for fuel cell system and verifies the effectiveness of the strategy by step loading experiment and actual vehicle fuel cell test experiment.In addition,this paper also studied the effects of improving the gas supply system,using new electrode materials and designing hydrophobic flow channels to improve the dynamic response capability of fuel cell.