The coordinated control system in once-through boilers has such characteristics as strong coupling

time-varying and difficult control.Against these problems

the multivariable predictive control with constraint conditions was applied to improve the control quality.In this system

the block algorithm was used to simplify the constraint conditions and reduce the computing amount

thus to improve the computing speed of predictive control system.The least square method based on the rolling window was employed to realize online identification of the coordinated system's object

to improve the accuracy of the predictive control.The unit's coordinated control system was established according to the fuzzy rules.Moreover

this coordinated control system was taken as the nonlinear object to carry out simulation experiments with constant and variable load

in sliding pressure mode.The results show that

this control method obviously improves the control quality and the solution speed of predictive control algorithm.The load control quality meets the inspection requirements

which is superior to the conventional PID control

and its computing speed is obviously faster than that of the conventional algorithm.