Modeling And Disturbance Rejection Control Of Electric Stage Of Fuel Cell And Supercapacitor Hybrid Electric Vehicle

In this paper,the modeling and disturbance rejection control issues of the electric stage of fuel cell and supercapacitor hybrid energy storage system are studied.The hybrid energy storage system using proton exchange membrane fuel cell and super-capacitor in parallel mode,through a unbidrectional Boost converter to control the discharing of the fuel cell,and the bidrectional Buck-Boost converter is used to control the charging and discharging of the supercapacitor.Finally,the two converters are connected to the DC-AC inverter,which drives the AC motor to connect to the same DC bus and the connection structure of the hybrid energy storage device and the motor is established.When the vehicle is starting,accelerating,or emergency braking,two desired control objectives are demanded,i.e.to stabilize the DC bus voltage and to meet the current demand of the motor.Firstly,the topology of the electric stage of hybrid electric vehicle is modeled.Secondly,it analyzes the sources and categories of system disturbance and determines the control objectives of the research.Finally,the system is designed and studied based on the method of Disturbance Observer Based Control(DOBC)and Finite Time Disturbance Observer Based Control(FTDOBC),respectively.Considering the nonlinear physical characteristics of energy storage system in electrical double parallel DC-DC power converters for electronic components,using Lyapunov stability theory,combining the backstepping recursive design method and nonlinear disturbance observer technique to design a novel active uncertainty attenuation controller,the DC bus voltage vdc can be rendered to track its desired value vdcd in a satisfactory precision.Compared with the conventional state feedback control strategy,the disturbance observer based control method can make the closed-loop system perform a stronger robustness.Furthermore,in view of the finite time disturbance observer can achieve accurate disturbance observation in a short period of time,and the disturbance rejection performance of the control system has been significantly improved.Therefore,for a typical multi-input multi-output,non-linear strong coupling complex system of fuel cell supercapacitor hybrid electric vehicle,by means of the backstepping recursive control strategy combined with finite time disturbance decoupling method to control the DC bus voltage,it can effectively improve the anti-disturbance performance of the system and realize the fast and stable regulation of the DC bus voltage.Finally,the numerical simulation is used to verify the effectiveness and feasibility of the controller designed in this paper,so as to have some application value for the development of hybrid electric vehicle technology.