Research On Control And Simulation Of Marine Turbine's Steam Seal Pressure

Steam rotation parts and static parts can not be in close contacted,we mustmaintain a certain gap to prevent accidents.Due to clearance,result a small part ofthe steam does not do work,flow to the air from the clearance,reduced theefficiency of steam.So steam seal must be placed between the rotating parts andstationary parts.The steam seal pressure has very tremendous influence to theefficiency of the turbine.In order to improve the efficiency of the turbine,usuallyusing the steam seal pressure control system for the control of steam seal pressure.With the development of the turbine technology,the requests to the steam sealpressure control system'S performance are getting higher and higher.There aremany problems in the currently used steam seal pressure control system of onemodel marine turbine during it be used,and it need to be improved in order toimprove the efficiency of the turbine.This thesis takes the original steam seal pressure control system as researchobject.Firstly,analysis its structure and principle,the control system use purewater as the working medium,according to the characteristics of control systemsand the advantages and disadvantages of the hydraulic system modeling methods,use the"gray box"modeling method for modeling the original control system anduse the Simulink simulation platform of Matlab for simulation , get the systemresponse curve and deviation Curves of all the circumstances,analysis theproblems of the original control system according to these curve.Because of thetime—delay of the system,use the traditional PID control technology is difficult toreach a good result.So,according to the system characteristics,a fuzzyself-tuning PID controller and a fuzzy-PID compound controller were designed tomake improvement to the system.After that,we obtain the simulation curvethrough the simulation tool.Finally,compare the performance of these three systems according to theoriginal control system,fuzzy self-tuning PID control system and fuzzy—PID compound control system'S simulation curve.According to the curve,the performances of the fuzzy self-tuning PID control system and the fuzzy—PIDcompound control system have a great promotion compare to the performance ofthe original control system.The fuzzy self-tuning PID control system has thefastest system response,smallest overshoot,most powerful anti-jammingcapability.So,the fuzzy self-tuning PID control system has the best performancein these three control systems and use fuzzy self-tuning PID control system forsteam turbine steam seal pressure control most appropriate.