Application Research On Main Steam Temperature Control Of Once-through Boiler Based On Internal Model Control

As the boiler develop towards large volume and high parameter supereritical generation units become more and more popular which reduce the coal consumption,economize the energy source,lessen the discharge capacity and enhance the economy benefit. The structure characteristics of supereritical generation units is introduced. The main's dynamic model is deduced,and the main's rough adjustment ,fine adjustment controlling strategies are introduced. The model has the characteristic of the timedelay, which can increase the overshoot and adjusting time. The common PID control method does not work very well.Therefore,how to improve the control quality of the system with delay time has been studied by many schools and experts.Then the structure, the method to design and properties of IMC have been introduced.The parameters of PID controller can be got based on IMC. There is only one tuning parameter,the method iseasy and feasible and can apply in reality.Dahlin control and Smith control are also introduced.It is shown that the Dahlin controller is a special case of the Smith controller and the Smith predictive control can run as an IMC control under some constraint conditions and the Dahlin control is equivalent to the IMC in case that the model matchs the plant.Particularly the fuzzy control is analysed. Fuzzy control does not need the exact model of the object and has good approximation capacity and robustness.Fuzzy control and IMC are combined ,the control strategy was proposed.After designing a kind of IMC controller,the fuzzy P regulator is used to set the proportional gain of the controller in real-time depending on appropriate fuzzy rules.With the help of MATLAB software,the simulation results show this control strategy has the advantages of short settling and strong noise immunity.