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

With the rapid development of automobile industry,how to develop and apply green and clean energy has become one of the important research topics.As a new type of green energy with non-pollution,low noise and high energy conversion efficiency,fuel cell has attracted great attention in the development of new energy vehicles,and is gradually regarded as the ultimate solution to solve the low-carbon green car industry.At present,the technical research related to fuel cell vehicles has made some progress,but the control technology of fuel cell gas supply system is still imperfect,and the control quality of gas supply system is of great significance to improve the output performance of fuel cell system.Therefore,aiming at improving the output power of the fuel cell system,this paper studies the control of the air supply circuit of the fuel cell system.The main research contents of this paper are as follows:（1）The air supply circuit model of fuel cell system is built by using MATLAB/Simulink simulation platform,and the key factors affecting the output performance of stack are analyzed.Firstly,starting from the reaction mechanism of fuel cell,considering the dynamic change of gas in internal flow field and the water transfer phenomenon of proton exchange membrane,the mechanism model of fuel cell stack is established;Then,according to the working characteristics of each component in the air supply circuit,the models of air compressor,supply pipeline,intercooler,humidifier,exhaust pipeline and back pressure valve are established respectively.（2）Aiming at the problem that the gas pressure in the cathode flow field in the air supply circuit of fuel cell system can not be measured directly.Firstly,the input-output feedback linearization and decoupling of the control-oriented nonlinear system is carried out,and the control variables corresponding to the gas pressure of the cathode flow field and the gas pressure of the supply pipeline are obtained;Secondly,a design method based on sliding mode differential observer is proposed to estimate the gas pressure in the cathode flow field in real time,and the stability and effectiveness of the observer are verified by setting different simulation parameters.（3）Aiming at the characteristics of the air supply circuit of the fuel cell system with multiple inputs and multiple outputs,strong coupling and strong nonlinearity,a control method based on model prediction active disturbance rejection is proposed for decoupling control.Firstly,the control-oriented nonlinear system is decoupled through input and output feedback linearization,and the control variables corresponding to the gas pressure of the cathode flow field and the gas pressure of the supply pipeline are obtained;Secondly,based on the linearized model obtained by feedback linearization,the unknown disturbance of the system is estimated by designing a disturbance observer and fed back to the model predictive controller to realize fast and stable tracking of the control target;Finally,in order to verify the tracking effect of the designed controller,the effectiveness of the controller is verified by off-line simulation test,the robustness of the controller is verified by parameter disturbance test,and the real-time performance of the control strategy is verified by hardware in the loop test.