Research On Main Steam Temperature Control Of Thermal Power Plants Based On Auto Disturbance Rejection Technique

With the increasing need of energy, thermal power generating develops in the wayof high-gain,large capacity and highly automated level.In order to supply better quality ofelectricity, this also puts forward higher demand for the control quality of the thermalpower units.The control objects of thermal power generating unit have the characteristicsof long time delay,big inertia,strong nonlinear.One of the important control objects is themain steam temperature.It is related to the safe operation of the entire unit.In order to get better control result of the main steam temperature.In this paper,anew control strategy-auto disturbance rejection control technique is applied,which isproposed by researcher Han Jingqing in Chinese Academy of Sciences.The paperintroduces the development status and basic algorithm principle of the ADRCtechnique.Compared with PID controller, ADRC has characteristics of better observationand compensation for inner disturbance and external disturbance.A large number ofcontrol parameters are set in ADRC,and there is no uniform program of parametersadjustment.This makes parameters setting become the crux of the matter.To solve thisproblem, by referring to the previous adjustment experience,this paper designs a programof parameters adjustment based on the principle of separation,the problem becomessimple and workable.Then by the simulation example, it is proved that low-order ADRCcontroller has a good control effect on high-order object. All of these provide atheoretical base for main steam temperature control by ADRC.By analyzing dynamic and static characteristics of superheated steam temperature insupercritical units,object model is established on matlab.S-function programming andpackaging into modules are applied in ADRC.The main steam temperature cascadecontrol system is formed by object models and ADRC.By a series of simulations theresults show that:compared with PID control,ADRC control strategy has a better controlaccuracy and quality,especially in rejection of system disturbance and robustness.