Research And Implementation Of Intelligent Control Of Circulating Fluidized Bed Boiler Drum Level

The topics as a330MW circulating fluidized bed boiler unit of Datang Thermal Power Project for the study, do a comprehensive and detailed study and experimentation for the boiler drum level control scheme and controller algorithm. Firstly, according to its own dynamics and detailed parameters of boiler drum level, establish a mathematical model of boiler drum level control system. Then, for conventional single impulse and double impulse control lack of effect on the control, drum level control scheme established cascade of three impulse. In the control algorithm, introducting fuzzy control which does not depend on accurate mathematical model of the controlled object to compensate shortcomings of high-precision conventional PID control but difficult to tune parameters. Combining the advantages of both, based on adaptive fuzzy PID and introduced ideas of variable universe, combined with the actual characteristics of drum level, design a simplified variable universe adaptive fuzzy PID controller, and was carried out simulation and applications. During AGC of unit, simplified variable universe adaptive fuzzy PID controller of this article is used in the boiler drum level control system, and conducted experiments on the DCS system. The results show that:the simplified variable universe adaptive fuzzy PID has a good effect, especially in the large unit load disturbance, showing a small overshoot, fast response speed, high control accuracy, adaptability of load disturbance and so on good quality control.From the research perspective, this paper includes the following aspects:(1) The main research background and significance of this project are described. Analyzes the importance of China’s electric power industry in the national economy, in view of the facts that the entire power industry dominated by thermal power plants, presented as the "twenty-first century clean combustion technology" circulating fluidized bed (CFB) boiler burning technology. Then the CFB boiler drum level importance for the safe operation of the boiler are described, describ the various control programs and some advanced intelligent control algorithms of boiler feed water in recent years, and a brief analysis of their advantages and disadvantages.(2) The specific object of study and control programs of this topic are established. Through the analysis of equipment and operation of circulating fluidized bed (CFB) boiler, draw the main factors affecting the level of the drum, and analyze its dynamic characteristics. Discusses and summarizes the various of boiler drum level control scheme, established the control scheme of this subject, to solve the "false water level" issue. Clear drum level control requirements, calculate parameters and transfer functions of system.(3) The main algorithm of master controller in drum level control scheme is studied and designed. Combined with the advantages and disadvantages of conventional PID algorithm, introduce fuzzy control algorithm which does not rely on mathematical model of the controlled object, using adaptive control theory, design an adaptive fuzzy PID controller. Introducing ideas of variable universe, design a simplified variable universe adaptive fuzzy PID controller. Using simulation software to build simulation models, and do the comparative analysis of control effect of each controller.(4) The actual control effect of the simplified variable universe adaptive fuzzy PID controller is demonstrated. The simplified variable universe adaptive fuzzy PID controller is configured completely in DCS platform. During AGC of unit, conduct some experiments such as value disturbance, load disturbance and value and load disturbance in order to verify the stability and control effect of this controller in the practical application.