Nonlinear Control Research On Coal Water Ratio Of Supercritical Unit On Backstepping Control Algorithm

Supercritical unit have small thermal storage capacity,low inertia, easilyover-temperature overpressure,and the control object exists a strong coupling,nonlinearity,distribution and other characteristics. As an important coal-water ratiocontrol signal of supercritical boiler, intermediate point temperature plays animportant role of deciding soda demarcation point, coal and water achieve matchingand advanced control of steam temperature, whose control quality directly affect thesafe, stable and economic operation of the unit.Thus, the ratio control ofsupercritical coal-water namely is the focal point and difficult point of the thermalengineering control of power plant. This paper based on the particular660WMsupercritical once-through boiler steam generator establish mechanism modeling,study the coal-water ratio control of supercritical once-through boiler by usingBackstepping algorithms and fuzzy control ideas,and improve the system performanceof coal-water ratio control.This paper make a very thorough mechanism analysis on the research object of a660WM supercritical once-through boiler steam generator and superheater.establishmechanism model by using lumped parameter fixed boundary, then implementdynamic inertia compensation correction by using a linear distributed parametermodel,subsequently infers intermediate point temperature transfer function due tofeedwater disturbance and fuel disturbance and superheated steam temperaturetransfer function,which meets a certain accuracy requiremeet. For the problem thatlarge change of the unit load, large disturbance and model mismatching occur result inpoor control quality and main steam temperature fluctuations, control law ofsupercritical mid-point temperature is designed based on Backstepping algorithms.Simulation experimental results show that the control system has better control quality.For the pros and cons of "water with coal" and "coal with water" control strategy usedin plants usually, propose a new control strategy combined with fuzzy control theory,then demonstrate the effectiveness of the control strategy by simulation results.