Modeling And Decoupling Control Of Proton Exchange Membrane Fuel Cell Engine Air Supply System

With the rapid improvement of production and living standards,the rise of automobile ownership has increased the demand for fossil energy.At the same time,automobile exhaust emission is one of the main causes of increasingly serious environmental pollution.In recent years,the national emission standards for passenger vehicles and commercial vehicles have become increasingly strict.Under this background,energy conservation,emission reduction and environmental protection have received great attention in today's society,which has greatly promoted the development of renewable energy.Among them,fuel cell as a kind of device that converts the chemical energy of hydrogen and oxygen into electric energy has been getting more and more attention from the market and researchers,and the investment of fuel cell technology is increasing due to its advantages of no pollution,low noise and high efficiency.At present,the control technology of fuel cell air supply system is still not perfect.A stable and fast air supply system control is very important for the performance of fuel cell system.In this paper,the fuel cell air supply system is taken as the research object,aiming at the problems existing in the system,the following aspects are studied:1.Based on the structure and working characteristics of the proton exchange membrane fuel cell air supply system and the basic physical principles such as mechanics,aerodynamics and electrochemistry,multiple sub-modules of the system were modeled based on the modular modeling idea,the mathematical expression forms were derived in detail.In addition,the test platform of the key component,centrifugal air compressor,was built,its dynamic performance and static flow MAP were tested and acquired.According to the performance requirement of the fuel cell used in vehicle,the physical parameters are matched,then a complete fuel cell air supply system under Simulink environment is obtained through the combination of various submodules.The dynamic characteristics of the system are analyzed by simulation results under different input.2.Based on reasonable assumptions,grasped the main features of the system and establish a control-oriented mathematical model.Then using fitting toolbox based on MATLAB,we get the polynomials about compressor gas flow rate on compression ratio and the rotational speed,which provides conditions for the nonlinear controller design,and comparison results of output curve between the plant and control-oriented model had the similar dynamic trend,verifying the validity of the simplified model.3.Because the air supply system is highly nonlinear,strong coupling features,this paper puts the feedback linearization method,which is widely used in nonlinear systems.The control law is designed using linear system control method based on the feedback linearization,and combine the Active Disturbance Rejection Control(ADRC)strategy,achieving real-time estimation and compensation for uncertainty to the system.In addition,the simulation results of the air supply system and the control-oriented model under the action of ADRC prove the effect on uncertainty.Finally,with the reference input of a typical step,the control strategy can ensure the controlled object has a smooth output with fast response speed.