Simulation Study On Variable Frequency Control Of Marine Sea Water Cooling System

The application of variable frequency technology in ships has great significance for energy saving and carbon emission reduction.Based on the principle of modular modeling,combined with the Simulink simulation tool in MATLAB and the Visual Studio 2013 software,this paper realizes the simulation of the frequency control process of the marine seawater cooling system.On the basis of building the mathematical model and simulation model of each equipment and control process in the system,the energy saving analysis of the system is carried out and the human-computer interaction simulation software of the system is developed.First of all,the research status and development trend of various technologies related to marine sea water cooling system are summarized.The significance of variable frequency control and energy saving in seawater cooling system is pointed out.The system composition,equipment technical parameters and performance indicators as late simulation data sources are pointed out.Then,because the sea water pump uses the frequency converter to control the asynchronous motor to realize the flow adjustment,therefore,paper carries on the detailed analysis to the Direct Torque Control(DTC)principle of the asynchronous motor in system,and has established the squirrel cage induction motor in the stator winding for the triangle connection.The mathematical model of DTC is presented.At the same time,the characteristic of single pump operation and the parallel operation of the sea water pump as the motor load are analyzed theoretically,which is the basis of building the simulation model.Besides,the Simulink simulation model is established based on the whole structure of the system,the DTC principle of the motor,operating characteristics of the seawater pump and the PID control of the motor speed based on temperature control.And the change of sea water pump flow is analyzed when the load changes.At last,according to the principle of variable frequency control of sea water pump,this paper analyzes the practical significance of the system in energy saving.By comparing with the operation of the constant speed sea water pump,sea water pump with variable frequency control of water supply system has remarkable energy saving effect is proved.After the establishment of the system simulation model,according to the operating characteristics of the system,on the Visual Studio 2013,using C#language,combined with WPF interface development technology,paper completes system simulation software development,which is a part of the simulation training system of the marine engine.