Study Of Pid Adaptive Controll Based On Genetic Algorithm For High Pressure Min Flow Valve

High pressure Min. Flow valve is special valve for extreme conditionsand it’s also key device that widely applied in the300MW、600MW and1000MW’s power units. As high pressure Min. Flow valve’s pressure differencebetween inlet and outlet is too high,its control system is also a time-delay andtime-dependent’s system, the requirement of control precision is strict,thetraditional fixed model PID controller isn’t often able to meet the customer’srequirement.On this condition, high pressure Min. Flow valve adaptivecontroller based on genetic algorithm is created and developed.This thesisdesigns high pressure Min. Flow valve adaptive controller based on geneticalgorithm and realizes continuously optimum PID parameters’ design accordingto real requirement. It abandons the traditional adjusting mechanism thatmechanical and pneumatic nozzle flapper adjusts PID parameter, simulating thegenetic and evolutional process of biology in nature environment and making anadaptive global optimization probability search algorithm,combiningquantitative calculation and qualitative analysis,optimum parameter adjustment in advance and knowledge base including to various kinds of emergencemeasure assures sustained stability of the system.Firstly,after introducing overseas and domestic research current status anddeveloped history of high pressure Min. Flow valve PID controller,according tocomposition and characteristic of Min. Flow valve control system,deeplyanalyzing the time-dependent cause of Min. Flow valve control system,andexplaining hardware and software of current controllers frequently used,thispaper created component of Min. Flow valve adaptive controller based ongenetic algorithm and operation principle of continuously optimum PIDparameters, completed built model of parameters identification constructor,newcontroller’s hardware and softwares established and set. After optimizingparameter, it need to calculate and judge whether it meets the customer’srequirement, and decides whether it can be used by knowledge base;there are anumber of pre-arranged planning supplied for some emergence special events inthe knowledge base,which sets appropriate outputs,in order to reach the effectof safty interlock.Meanwhile,this article researches the algorithm of H2controller analyticmethod and realization of genetic algorithm parameters optimumtechnology,creates the adaptive controller optimum method of combininganalytic method and genetic algorithm, on the hand,it assures the stability of thesystem;on the other hand,it also decreases hunting zone of genetic algorithm and improves search precision.As the static control system of high pressureMin. Flow valve is stable,when actual condition is operated,it usually occursvibration,after model parameters’ perturbation, using Matlab/Simulink software,through abundant experiments, compared with PID parameters Ziegler-Nicholsmethod and response curve obtain,PID ones by genetic algorithm optimizinghas better robustness and characteristics of adaptive searching optimization,evenif time constant、delay and static gain of the controlled object have been changedat the same time,adaptive controller still assures better control response,thesmaller overshot,the stronger robustness and pretty standard performance,and itpoints out controller parameter optimization based on genetic algorithm is thefeasibility and validity,which is more practical PID parameter optimizationstrategy.