| At present, with capacity of the units continues to improve, thermal power plants need to meet demands of power peaking. In the power plant, as an important parameter, the control effect of superheated steam temperature will directly determine plant's safety and economy. Superheated steam temperature is time-varying, nonlinear characteristics and large delay. The conventional cascade PID control system and controller parameters is carried out under the particular load, when the load changes, blowing ash and other disturbances occur, the control effect gets worse.Internal model control is controller design of an advanced control strategy based on object mathematical model, which has only one adjustable parameter. By adjusting the filter parameter, the closed loop system take into account the control precision and robustness requirements. According to internal model control and feedback control features, by Taylor series, PID parameters based on the internal model control method can tune.Multi-model control select several operating points of the controlled object, create multiple models which can be a good approximation of the entire system's dynamic characteristics, and then design corresponding controller respectively. In the actual running, according to the controller scheduling mechanism, such as the use of weighted output or switch output, output controller.Superheated steam temperature based on the characteristics of object, cascade system is still used, deputy circuit parameters of the controller with PI control; Vice-loop and the composition of the inert zone by approximation of the generalized controlled object into a first-order inertia plus pure delay, the main loop parameter setting is based on internal model control tuning parameters; superheated steam temperature models establishe according to different load points and the corresponding controller tuning parameters. According to some scheduling mechanism, when the load changes, corresponding controller output. |
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