Research And Application Of Fuzzy Control For Reheat Steam Temperature Control System

With the rapid development of China’s economic, the electric power system hasbeen towards the changes of larger capacity and high level of automation. Reheatsteam temperature control is an important branch of the large-capacity thermal powerplant control, and its importance is self-evident. However, due to the complexity ofthe object, the conventional PID control is difficult to meet the performancerequirements. Fuzzy control is based on the empirical knowledge of experts toconstruct language information and converts it to control forms of control decisions. Itdoes not need to establish a mathematical model of the controlled process, and caneffectively solve the problem of some unknown factors and uncertainties that exist inthe system. The control strategy is relatively simple to establish viable, which iswidely used in nonlinear, time-varying control process time delay system. This paperselects burner tilt model of reheat steam temperature for the study, and applies fuzzycontrol theory to the large inertia and large delay control system.First we propose the status of reheat steam temperature control, noting thefeatures of reheat steam temperature，the influence factors and major adjustmentmethod of the control system. Then introduced the basic control principle and fuzzycontrol system design methods, pointing out their strengths and weaknesses, thenimprove fuzzy controller functions on the basis of performance. In order to achieve noresidual bias control, proposed a complex controller combining fuzzy control andconventional PID controller.Through MATLAB simulation experiments to clarify the affect of scaling factor,scale factor and weights to the fuzzy controller, then according to the law we proposeselection method of parameters, design fuzzy adaptive controllers. Simulation resultsshow that the adaptive controller can achieve better performance.