Networked predictive control of main steam temperature for once-through boiler based on reverse transfer strategy

In once-through boiler, main steam temperature control system was complex, which had the large control chain span. According to the analysis of the characteristics of main steam temperature control system, a networked predictive control method based on reverse transfer strategy for the cascade system was presented. The recursive least squares(RLS) with forgetting factor was used to identify subsystems, which was adapted to the need of once-through boiler's variable conditions. In order to make the desuperheat spray have the enough adjustment range, the setting points of the reverse transfer strategy were designed by the online identification of the main steam temperatures' leading segments. Constraint conditions of predictive control were used to ensure that the intermediate point's temperature and the superheater outlet temperatures had enough superheat. A simulation for superheat steam temperature control system of one once-through power plant was carried out by the presented method. The result shows that the control system's effect is better than the conventional cascade control system. © 2015 Chinese Society for Electrical Engineering.