A fuzzy adaptive pid control method for thermal power unit superheated steam temperature prediction

Abstract

The invention provides an overheating steam temperature predicting fuzzy self-adaptive PID control method for a thermal power generating unit. The method comprises the steps that controller parameters are initialized; data of overheating steam temperatures of the thermal power generating unit at all moments and temperature reducing water-spraying valve opening degree are acquired; an augmented state space Takagi-Sugeno fuzzy model is established based on process variable data; the augmented state space Takagi-Sugeno fuzzy model is utilized to optimize and solve PID controller parameters; the temperature reducing water-spraying valve opening degree is controlled according to the PID controller parameters at the current moment, and accordingly overheating steam temperature is controlled. A next sampling period begins, the step 4 is repeated, and the process from the step 4 to the step 6 is repeatedly performed. The method integrates the advantages of fuzzy control, prediction control and PID control, namely, a prediction function of prediction control, a nonlinear-system excellent control effect of fuzzy control, and convenient realization of PID control, the control quality is high, the form is simple, and the method is easy to achieve, economical and safe.

Description

technical field [0001] The invention belongs to the technical field of thermal automatic control, and relates to a fuzzy self-adaptive PID control method for superheated steam temperature prediction of a thermal power unit. Background technique [0002] Superheated steam temperature is directly related to the safety and economy of thermal power plant unit operation, and it needs to be monitored during unit operation. In recent years, with the development of the electric power industry, the capacity and parameters of thermal power generation units have been continuously improved, and large-scale units are gradually required to participate in the peak regulation of the power grid. The large-scale load changes have increased the difficulty of superheated steam temperature control. How to achieve superheated steam? The high-quality control of steam temperature under a wide range of variable loads to adapt to the current peak-shaving operation of thermal power units has not yet b...

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Problems solved by technology

At present, there have been many reports on the application of model predictive control to superheated steam temperature control, but most of them are based on the linear model as the basis of predictive control design, and the characteristics of the object change greatly during the operation of the unit with a wide range of variable operating conditions , the linearization method cannot achieve a satisfactory control effect

At present, there is also a control method that combines fuzzy model and model predictive control, but the specific application of the model and the selection of control parameters in fuzzy predictive control are relatively complicated, and it is difficult for engineers to master it. It is far less easy to understand and simple in form than PID control, so It is very difficult to implement, and it is difficult to be practically applied to the superheated steam temperature control of thermal power units

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