The Optimization Research Of Propulsion Control Strategy For Small Electric Propulsion Ships

In recent years, with the development of power electronic and the increasingly maturationof large-power AC motor variable frequency speed control technology, the ship electricpropulsion system has great breakthrough in mobility, reliability, efficiency and propulsionpower and so on, and the application field of electric propulsion technology has been expandingconstantly. However, the feature of ship dynamic characteristics has been with high coupling,nonlinearity, large delay and large inertia etc., and the statistical properties of randominterference by external wind, current and waves, also changes dramatically with different seaconditions. How to achieve electric propulsion system running safety, reliability and efficient,that is a hot research spot of ship electric propulsion system. The study of electric propulsionsystem started relatively late in China, and has a large gap with foreign modern integratedelectric propulsion technology. Therefore, study on the control system and control strategy of theship electric propulsion system, will play a certain role in promoting the development of marineelectric propulsion. This paper mainly aimed at small electric propulsion ships, focus on theoptimization research of the control strategy and achieve its electric propulsion control system.Specifically, this study mainly works described as follows:1. The propulsion module and load module of electric propulsion system were analyzed,including propulsion motor operating characteristics, control module and the characteristics ofthe screw propeller; The matching of hull-motor-propeller characteristics was studied andhull-propeller mathematical model was established;2. Analyzed and summarized the propulsion characteristics and control requirements ofsmall electric propulsion ships. Depending on the ship integrated electric propulsion controlsystem, a comprehensive optimization control strategy of small electric propulsion ship wasproposed, and the propulsion control system model of small electric propulsion ship wasestablished;3. The hull-motor-propeller simulation model of small electric propulsion ship was set upwith Matlab/Simulink. The model performance was researched by simulation under differentoperation condition based on ship real parameters. The simulation results showed that theestablished model has optimized on effect to system controllability and stability;4. Based on the presented optimization control strategy, through hardware designing andsoftware programming applied the PLC, frequency converter and the bus control technology, some functions of the existing ship integrated electric propulsion research platform in laboratorywere improved. Finally, the model simulation results were verified by the experimental results ofthe experimental platform. The results showed that the presented optimal control strategy canimprove the maneuverability, safety and stability of small electric propulsion ship.