Study on the layered predictive control algorithm for the main steam temperature of ultra-supercritical units

Aiming at the main steam temperature control problem of ultra-supercritical units under variable loads conditions, a predictive PID control algorithm with layered structure is proposed. The cascade PID control is applied in the lower circuit which can realize the application in DCS system through configuration language programming. The generalized predictive optimization is applied in the upper circuit which is used to conduct PID parameter setting instead of control engineers. By introducing least square method with forgetting factor recursive, the model parameter identification in rolling window is realized and the PID parameters tuning optimization model with predictive index is established. The simulation results show that the proposed algorithm can adapt to the model change process of the controlled object of main steam temperature and is qualified with strong stability and robustness.