Research On Air Circuit Decoupling Control Of Vehicle Proton Exchange Membrane Fuel Cell System

Under the background that environment and energy have become global common concerns,new energy vehicle technology,with the support of various countries,will become a more important trend in the future.Fuel cell vehicle technology with hydrogen as energy supply will also become an important breakthrough direction of new energy technology in the future.With the marketization of fuel cell,the technology breakthrough and research and development of fuel cell technology have also been widely concerned.This paper mainly studies the model and control of the air supply system of the proton exchange membrane fuel cell for vehicles,and builds a model and test bench for the fuel cell air supply system.Aiming at the characteristics of the nonlinearity and strong coupling of pressure and flow,in order to avoid the interference of unfavorable factors and improve the performance of the fuel cell system,it is necessary to carry out decoupling control.The specific contents involved are mainly as follows:Based on the research background of the subject and the current status of the control problem,this paper first clarifies the principle of the proton exchange membrane fuel cell structure and analyzes its output characteristics and polarization phenomena.According to the principles of electrochemistry and thermodynamics,the output voltage and material consumption models of fuel cell were established.Secondly,referring to the model assumptions and mathematical formulas of the cathode air system,a dynamic model of the system is established.The main parts are air compressor,air supply pipeline,return pipeline,back pressure valve and cathode interior.Using the results of actual experiments,the outlet flow of its important component air compressor was fitted.According to the ideas established by the process unit model and the mathematical model derived,the fuel cell air system model is built in Simulink,and the voltage,current,pressure and flow of the fuel cell are simulated and analyzed.Then the experimental platform of the system is built,the communication network structure of the system is designed,the loading and unloading experiments are carried out,and the relevant experimental data are recorded.By comparing the results of bench experiment and model simulation experiment,and analyzing the changes of main parameters with the experimental process,it is proved that the model can correctly reflect the bench experiment process,which provides a platform and foundation for the subsequent controller design and simulation.Finally,in order to solve the control problem of the pressure and flow coupling of the fuel cell air system,the control algorithm logic of the air circuit is deeply analyzed.According to the decoupling control process of the multivariable process control system,the controller of the fuel cell air system is designed.On the basis of feedforward control,the operating points of the system under different pressure conditions are matched with the decoupling control coefficients,and then the decoupling control coefficients of the fuel cell air system at different operating points are determined to realize the process of decoupling control.The simulation results show that the decoupling control process proposed in this paper can well realize the decoupling control of the flow and pressure of the fuel cell air system.The controller has a simple structure,good decoupling effect and practical performance.