Main Steam Temperature Control of Thermal Power Boiler Based on Dynamic Matrix Control

A predictive control strategy of main steam temperature based on dynamic matrix control is proposed and the characteristics of large inertia, pure lag and nonlinearity of main steam temperature control for thermal power boilers are taken into account. According to the characteristics of superheated steam transmission channel, the disturbance of cooling water flow is used as feed-forward compensation. A dynamic matrix controller is designed by comprehensive consideration of disturbance factors such as unit load, fuel fluctuation and so on. The algorithm adopts a rolling optimization strategy with finite time interval and introduces an error-based feedback correction algorithm so that uncertainties caused by model mismatch, time-varying and interference are comprehensively considered, and the influence caused by these factors is compensated in time, so as to improve the robustness of the system. Simulation experiments and comparisons with the conventional PID and Smith control strategies show that the adjust time and the overshoot of the proposed strategy reduce by up to 314.28 s and 12.6% respectively under disturbance, and by up to 516.66 s and 15.46% under the case of model mismatch. Results of engineering applications show that the deviation of main steam temperature control is less than ±5℃, and both the dynamic and steady-state performances are greatly improved. Actual requirements of the main steam temperature control system of power generation boilers are effectively met. © 2019, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.