Adaptive Backstepping Sliding Mode Control Of Methanol Reforming Fuel Cell Hybrid Power System

The mass production and application of traditional internal combustion engine vehicles cause the reduction of fossil energy,and increasingly damage the environment.Fuel cell vehicle is regarded as one of the most important developing direction of new energy vehicle since its high efficiency and zero emission.An on-board methanol steam reforming fuel cell power system hybridized with the lithium battery for vehicle surpasses the barrier of low hydrogen storage density,slow transient response,limited output peak power and being unable to recover barking energy issued in general high-pressured hydrogen storage fuel cell vehicle.In this study,an on-board methanol reforming fuel cell hybrid power system modeling and control is presented.The lithium battery has superiority in terms of high energy density,long life and large discharge current.The methanol reforming applied to the hydrogen production system exhibits many advantages because of its high H/C ratio,low cost and good security.Combined with the features of lithium battery and methanol reforming,the problem of hydrogen storage fuel cell with insufficient hydrogen storage density,load response and the ability of recover barking energy can be overcome.Benefit from the fast response and robustness performance of adaptive sliding mode control,the power management strategy based on the state machine with adaptive sliding mode controller is designed to implement the power distribution of fuel cell hybrid power system.Based on the mechanism,including the effects of steam methanol ratio,methanol flow ratio as well as reforming temperature,and semi-empirical formula of methanol reforming,the methanol reforming fuel cell model contains hydrogen diffusion equation and equivalent circuit method is primarily presented.A control-oriented model of methanol reforming fuel cell/lithium battery is modeled by the operating principle of converter and the charge and discharge characteristics of lithium battery.The parameter matching of the fuel cell hybrid power system is performed through the vehicle dynamic model according to the vehicle dynamic theory.Furthermore,an on-board methanol reforming fuel cell vehicle hybrid power system modeling and control simulation analysis is developed in MATLAB/Simulink,and the experimental validation is also carried out.Using the adaptive sliding mode control theory,the sliding mode surface based on Lyapunov stability principle is selected.Then,the disturbance observer is designed,and the adaptive control law is solved.The power management strategy based on the state machine with the fuel cell current adaptive controller is proposed to ensure the driving and braking continuously through the hybrid power system under different vehicle operation conditions.The simulation and experiment results indicate that the proposed controllers can track the current set point well with fast response,high precision and robustly against disturbance.Finally,the output power of the fuel cell is stable and smooth in different operation conditions,and the durability of the fuel cell can be improved.