Control optimizing method for master controller of supercritical unit boilers

Abstract

The invention discloses a control optimizing method for a master controller of supercritical unit boilers. The control optimizing method includes introducing an inertial element F(s) and a lagging element y1 into a feed-forward control branch to replace a modification function My(s) for a main vapor pressure input value ysp which is randomly set by an original system; providing input signals of the lagging element y1 by an element F(s), and leading reference signals yf outputted by the lagging element y1 to act on an input end of a closed-loop control element; and additionally optimizing a transfer function Mu(s) of the feed-forward control branch of an original boiler master control system into a pressure compensation transfer function Mf(s), meeting the requirement of parameter-variable running of a feed-forward function uff of the original boiler master control system, leading the uff and the yf to jointly act on the closed-loop control element, then controlling a follow-up executing mechanism and accordingly realizing master control for the boilers. The control optimizing method has the advantages that the master controller of the boilers can quickly and accurately output instructions to a fuel master controller and a water supply master controller, accordingly a main vapor pressure control effect is guaranteed, response characteristics of load are further ensured, and control quality of the unit and economical indexes are improved.

Description

technical field [0001] The invention relates to an optimization control method, in particular to a supercritical unit boiler main control optimization control method. Background technique [0002] With the development of material technology and the continuous improvement of energy-saving requirements, supercritical and ultra-supercritical units have been more and more widely used in domestic power supply construction. Nowadays, due to the influence of macro factors, large-capacity units all adopt variable load operation, frequency regulation and peak regulation, and the daily load changes in a wide range. With the development of social economy and science and technology, the capacity of the power grid is getting bigger and bigger, and the quality of electric energy is also getting higher and higher. For the safe and stable operation of the power grid, all large-scale thermal power units are required to use the AGC function, and the AGC is required to control the load of the ...

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Problems solved by technology

[0005] (2) Since the once-through boiler has no steam drum, it has a one-time pass characteristic, and the working medium flow and energy flow are coupled with each other, so that the main control parameters of the unit, power, pressure, and temperature, are affected by the opening of the steam turbine valve, fuel volume, and water supply. Therefore, there is a strong nonlinear coupling between various control loops, such as feed water, steam temperature and load control loops, and the involvement between the machine and the furnace is serious;

The problem with this feed-forward control method is that in order to reduce the overshoot of the controlled object, appropriate control system parameters are required, and sometimes the response speed of the system output to the set value will be reduced, otherwise the overshoot will be large

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