Font Size: a A A

Active Disturbance Rejection Control Of Lean Pre-mixed Combustion Oscillation

Posted on:2018-07-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:K X M MaFull Text:PDF
GTID:1368330566487958Subject:Power Engineering and Engineering Thermophysics
Abstract/Summary:PDF Full Text Request
Unstable combustion,characterized by disturbances,essential non-linearity,and shifting operating conditions,is a practical problem in gas turbines.Since the precise mathematical model of flame is hard or in some conditions impossible to acquire,model dependent control strategies are ruled out.Therefore,active disturbance rejection control(ADRC)of simple structure and model independence is suitable for this scenario.In this work,a lower order ADRC design methodology is given along with detailed theoretical analysis.Through simulation on the identified flame model,and the platform experients,the validity of proposed design is confirmed.Firstly,the acquisition of the initial ADRC controller parameter values is a haunting issue.In this work,the initial ADRC parameter values are obtained from two degree of freedom PID control system,since these two control strategies are structurely similar.A frequency analysis based lower order ADRC design is given through equivalent transformation from two degree of freedom PID control realm.Through the quantitative relationship between the ADRC parameters and the corresponding equivalents of two degree of freedom system,the initial values of the ADRC controller could be calculated directly.Based on the pattern of the influence of the extended state observer parameters and the controller parameters on the closed system performance,a parameter tuning law is given.Secondly,an ADRC closed loop robust stability analyzing means and an ADRC parameter stable region calculation methodology is founded on the equivalent two degree of freedom PID system closed loop robust stability theory.Simulation results validate ADRC control effects on single input single output(SISO)process.Thirdly,from the proposed lower order ADRC control system design methodology for SISO process,a lower order ADRC solution for multi-input multi-ouput system haunted by intergrating loops and coupling dynamics in pratical gas turbine combustion process.Finally,to apply the proposed ADRC system controller design in unstable combustion,the frequency response characteristics of the flame(in Rijke tube and in industrial combustion chamber)are obtained through experiments and analyzed,along with the nonlinear feature of combustion.From the measurement of combustion system dynamics,a mathematical model is set.Simulation results on the identified model and the experiments outcome on both Rijke tube and industrial combustion chamber indicate that the proposed ADRC design is viable for the combustion oscillation suppression and for other industrial application.
Keywords/Search Tags:active disturbance rejection control, two degree of freedom, PID, Unstable combustion
PDF Full Text Request
Related items