Research On Thermal Management System Of Proton Exchange Membrane Fuel Cell

Proton exchange membrane fuel cell(PEMFC)has the advantages of high energy efficiency,long working life and no pollution of reaction products;As a low temperature hydrogen fuel cell,effective thermal management temperature control has an important impact on the durability,stability and reaction efficiency of fuel cell.Therefore,it is of great significance to study the thermal management system of PEMFC.In this thesis,the working principle and structure of PEMFC are analyzed;The energy loss and voltage polarization loss in the electrochemical reaction process of fuel cell were analyzed to determine the optimal working temperature of fuel cell thermal management system.The influence of current density and gas humidity on the working temperature of fuel cell system is analyzed,and the effect of different influencing factors on the working temperature of fuel cell system is analyzed.This thesis studies the dynamic relationship of heat balance in the working process of PEMFC,and designs the overall scheme of fuel cell thermal management system.Through calorific value analysis,the hardware selection of fuel cell thermal management system is completed.According to the characteristics of real components,the simulation model of fuel cell thermal management system is established by using Matlab/Simulink,and the temperature change process of thermal management system under 2k W heat production condition is simulated and analyzed.This thesis studies the temperature control algorithm of fuel cell thermal management system;The fuzzy PID control algorithm of double in and three out is established.The temperature difference E between the set temperature and the actual temperature and the change rate of temperature difference EC are used as the double input variables.The PID parameters K_P,K_iand K_dare self-tuning by fuzzy rules to optimize the control effect of cooling fan,circulating water pump,proportional control valve and other components.Based on the fuzzy rules and neural network self-learning characteristics,the fuzzy neural network PID control algorithm is established to complete the optimization of fuzzy logic rules.Through the comparison and analysis of the simulation results,it is verified that the fuzzy neural network PID control has a more optimized control effect of the thermal management system and the prediction effect of the temperature change.In this thesis,PXI hardware system is used to develop the test platform of fuel cell thermal management system.Solid Works is used to design the three-dimensional structure and complete the hardware design and development of thermal management system.The upper computer software of fuel cell thermal management system test platform was developed based on veristand,and the simulation model and control algorithm were verified.The fuel cell thermal management system was developed by using rapid prototyping;By changing the heating power of the stack simulator,the fuel cell stack tests under various working conditions are simulated.The test results show that the fuel cell thermal management system developed in this thesis has good temperature control effect,ensures the uniformity of the system heat cycle,and realizes the stack simulator always working in the allowable temperature range.