Study Of Model And Control System Of Combustion System Of Circulating Fluidized Bed Boiler

The Circulating Fluidized Bed(CFB) Boiler with the advantages of widely fuel adaptation and less air pollution emission,had been widely applied in power industry and thermal power plant.However,characterized by large time delay,large inertia,strong coupling and non-linear,traditional control strategy cannot work well.Therefore,this thesis is mainly concerned with modeling and control strategy of combustion system of CFB,and main contents in this thesis are as follows:1) Deep study of combustion system of Domestic Manufactured 75t/h CFB,which is applied widely,is performed,and the factors and parameters in combustion system is analyzed.Then systemic experimental modeling is performed for home-made 75t/h CFB boiler works with Step Response experience,and models of bed temperature control system and main steam pressure control system is set up with direc identification.Then some improvement suggestion is summarized based on analysis of model and data on-line.2) Active-Disturbance-Rejection-Controller(ADRC)shows satisfactory performance for the control objectives with such characters as large inertia,strong coupling,and large amount of disturbances.However,parameters tuning of this controller is a problem.In this thesis,a synthesis tuning algorithm with generality is proposed.In this algorithm,tuning of Extended State Observer(ESO) is analyzed as multiobjective optimization problem and multiobjective optimization algorithm-NSGA-â…¡is applied.The best comprise solution based on fuzzy theory is applied to extract tuned parameters from pareto solution.Then Levenberg-Maquardt is applied to tune NLF based on tuning of ESO and tracking differentiator(TD).The results of many numerical simulations demonstrate that ADRC of 2-order and 3-order plant can be tuned and it proved the universality of the synthesis tuning algorithm.3) Cascade ADRC-PI controller is designed for main steam temperature system of CFB, and synthesis tuning algorithm is applied too.Simulation results demostrate the disturbance rejection character and robust character of this controller,and effectiveness of the tuning algorithm.4) Application of ADRC on combustion control system of CFB is studied.For the characters of combustion system,application of ADRC in system with large delay and system with multi-varible is studied.Then ADRC of combustion system of CFB is desigened and the parameters of ADRC are tuned with synthesis tuning algorithm.The simulation result demonstrated the decoupling ability and model adaptive of ADRC control system.5) The hybrid characters of combustion system of CFB is investigated and the logic input sand non-linear states is looked as the important factors which influence system analysis and control system design.Then based on analysis of on-line data,the work condition with shut-up of one coal feeding system is taken as one important work condition with more frequency.Then the number of working coal feeding system and load is introduced into model. The system is analyzed based on DHA framework,and MLD model is produced with HYSDEL programming language.Then MPC algorithm based on MLD model is applied to bed temperature control system.