Nonlinear intelligent predictive control technology-based super critical unit reheating steam temperature optimal control system

Abstract

The invention discloses a nonlinear intelligent predictive control technology-based super critical unit reheating steam temperature optimal control system. The control system is composed of a flue gas baffle control loop and an accident water-spraying control loop; each of the flue gas baffle control loop and the accident water-spraying control loop includes a feedback loop and a feedforward loop; according to the feedback loop of each of the two control loops, a nonlinear intelligent predictive controller is adopted as a main controller; each of the feedforward loops includes a fuzzy intelligent feedforwarder; and the input variables of the fuzzy intelligent feedforwarder include a deviation variable e and deviation change rate de / dt. According to the control system of the invention, nonlinear intelligent predictive control is adopted, so that a constrained optimization problem can be processed conveniently. The calculation process of the control system is very clear and simple. When the control system is applied to engineering application, programming is very easy to implement, and the control effect of the control system is better than that of traditional PID; and the feedforward variable is additionally adopted, so that fast adjustment of the opening degree of a flue gas baffle can be realized, the overtemperature of the metal wall of a reheater can be prevented, a control effect enabling effective control on reheating steam temperature can be realized, and the economical efficiency and security of the operation of a boiler can be ensured.

Description

Technical field [0001] The invention relates to a novel reheat steam temperature optimization control system of a supercritical unit based on a nonlinear intelligent predictive control technology, which belongs to the field of thermal energy power engineering and automatic control. Background technique [0002] The reheated steam temperature of the supercritical unit is mainly controlled by adjusting the reheating flue gas damper, and the accidental water injection is used as an auxiliary adjustment method. The controlled object of reheated steam temperature has great lag and inertia (above 15min), and the reheated steam temperature is affected by various factors on the flue gas side and steam side, and the reheated temperature is closely related to the efficiency and safety of the unit Related, simple adjustments cannot guarantee the high quality of supercritical units during operation. Conventional PID control systems are difficult to effectively suppress large-scale changes in...

AI Technical Summary

Problems solved by technology

The controlled object of reheat steam temperature has a large hysteresis and inertia (more than 15min), and the reheat steam temperature is affected by various factors on the flue gas side and steam side, and the reheat temperature is closely related to the efficiency and safety of the unit Related, simple adjustments cannot guarantee the high quality of the supercritical unit during operation. It is difficult for the conventional PID control system to effectively suppress the large-scale change of the reheating steam temperature. Only the optimal control strategy based on the large-delay control theory can be integrated. Use auxiliary means such as adjusting the opening of the flue gas baffle and accidental water spraying to effectively control the temperature of the reheated steam

[0003] From the perspective of control principle, the nonlinear predictive control method is an effective method to solve the related problems in the reheating steam temperature adjustment process, but the traditional nonlinear predictive control algorithm is very complicated, and its control function (the opening of the flue gas baffle) It is often limited, which makes the solution problem of nonlinear predictive control algorithm more complicated, and its application in practical engineering is almost impossible

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