Experiment And Simulation Analysis Of Supercharged Marine Boiler Water Level Control System

As the supercharged marine boiler is characterized by frequent load changes and highheat density，it is difficult to keep drum level of supercharged marine boiler in practicalapplication. In recent years，some of researches have been done by domestic and foreignresearchers. However，most of the researchers have proposed a new algorithm which isapplied in regular control system，and verification has been given with simulation of systemthat includes the transfer function and the control algorithm. On the one hand，the new controlalgorithm is hard to apply in practical control system; On the other hand，because of boilersystem is variable and coupling，using transfer function as controlled object may leads to partof dynamic characteristic of drum level being ignored. Based on condition state above，theauthor put forward four input control system that based on regular three in put control systemand add fuel flow rate as feedfoward of controller.The system have swift respond ofdisturbance fuel flow rate and easy to apply.At first，the author applies four input control system in small supercharged boilerexperiment unit. During experiment，parameter of controller has been setting.Comparisonbetween three input control system and four input control system is made.The conclusion isthat four input control system is easy to apply and it has better control performance when thatfuel flow rate is changing.After experimental verification of the control system，on the purpose of analysis thesysyem deeply，the author have established simulation model of supercharged marine boilersystem.Then the simulation model is been calculated by Matlab/simulink.The three inputcontrol system，cascade three input control system and four input control system simulationmodel is established after the result of simulation have been checked.The whole system，including control system and boiler system has been given different step disturbance.Thedynamic response of drum water level is been used to investigate influence given by differentvalue of controller parameter.The optimal value of control parameters have been given.Atlast，comparison between response of feed water flow rate，steam flow rate and fuel flowrate step disturbance has been given，the result shows that four input control system havebetter performance than other control systems when fuel flow rate is changing.In the paper，the author tries to find out a simple and effective way to optimize thecontrol of drum water level.The four input control system has been put forward and beenexpected to make marine supercharged boiler is able to run on more severe condition. As themarine supercharged boiler is the heart of marine steam power system，its stable operation is important and meaningful in the aspect of economy and safety.Therefore，the four inputcontrol system has certain engineering value.