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Modeling And Simulation For Marine Electrical Propulsion System

Posted on:2009-11-01Degree:DoctorType:Dissertation
Country:ChinaCandidate:H B GaoFull Text:PDF
GTID:1102360272992419Subject:Marine Engineering
Abstract/Summary:PDF Full Text Request
Marine electrical propulsion system gains many advantages over traditional diesel drive system,which is a hot research area in ship manufacturing industry. Modeling and simulation research of marine electrical propulsion system,which can describe static and dynamic running processes,is helpful to discover inherent principles and to direct the design and management of the system.The dissertation develops from the following aspects:the design and analysis of experiment device,mathematic modeling of marine electrical propulsion system, contrast between simulation results and experiment results,simulation for malfunction and typical working conditions,calculation of the drive motor's energy saving,motor control optimization strategy.The dissertation accomplishes three items of research:1) The marine electrical propulsion system of Wuhan University of Technology is designed and its components,features and working principles are analyzed.A whole set of mathematic models for the lab's equipments are set up,which include drive engine,regulator,generator,voltage regulator,transformer,converter,filter and propeller.The whole set of models can be used for system analysis.In order to simulate propeller load realistically,the Chebyshev polynomial fitting method is utilized to express the Nordstrom propeller atlas across four quadrants,which can be adjusted according to various propeller types.The ratio between load torque and real ship's propeller load is derived from analyzing the machine motion equation,so that the experiment equipments can have the same dynamic characters as the real ship. Those mathematic models of the equipments are described by Mast language,and the whole set of simulation models of system are designed in Saber.The veracity and validity of the system simulation models are verified by contrasting the models' experimental data with lab's equipment experiment data.2) The typical running conditions,harmonic and malfunctions are simulated to discover some characters and laws of marine electrical propulsion system.Such typical running conditions as start,braking and emergency reversing are simulated to study the response time,current,voltage and torque.The performances of stopping and braking are contrasted between diesel propulsion and electrical propulsion with the same tons and power.The features under low speed condition are also studied. The harmonic effect on marine electrical network is analyzed,what is more,the input alternating current filter is designed which is proved to be useful by simulation experiment.Such malfunctions as rectifier malfunction,earth malfunction,bus short-circuit and inverter malfunction are simulated.Some basic rules are found through simulation tests and some guide advices are given.3) The running efficiency of drive motor is studied by analyzing the definition of motor and the energy-saving potential is found.In order to find out the best efficiency point,the minimum loss control strategy is studied at an angle of energy transform. The iron-loss asynchronous motor model is built to calculate the best efficiency point and corresponding flux.The minimum loss control strategy is proved to be effective by simulation experiment and the adaptability range of efficiency optimization method is also discussed.Aiming at problem of the bad dynamic response character with the best efficiency control,a new drive motor control strategy is put forward to take both efficiency and dynamic response into consideration.The new modified vectrol control strategy is validated to be useful by contrasting simulation experiments with traditional vector control method.It offers a feasible solution to improve the efficiency of marine electrical propulsion system with good dynamic response character.The dissertation is supported by the following projects:State "211" Project-"WUT Marine Electrical Propulsion Simulation Lab";doctor foundation projects of the State Ministry of Education of PRC(No.20040497012);the Research Fund of HSSE,WHUT,the State Ministry of Education(No.HSSE0802).
Keywords/Search Tags:Electrical propulsion System, Modeling, Simulation, Optimal control
PDF Full Text Request
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