Research And Simulation Of Electric Propulsion System In Small Ship

Marine electrical propulsion system gain many advantages over traditional diesel drive system, which is hot research area in ship manufacturing industry. Modeling and simulation research of marine electrical propulsion system is helpful to direct the design and management of the system. This paper mainly aimed at small electric propulsion ships, focus on electric propulsion control strategy and its load characteristics.Firstly, according to the characteristics of small ship, The propeller which is the load of electric propulsion system have been researched. The propeller open water characteristics are analyzed, as well as the resistance characteristics, thus the establishment of hull-propeller mathematical model and simulation model based on MATLAB/Simulink; according to the characteristics of electric propulsion in small ship, Reducer is presented in advance between the electric motor and propeller, and have established the reducer simulation model combined with the hull-propeller. By analyzing the speed of the propeller, the speed of the ship, the thrust of the propeller and the torque of the propeller, The simulation results show that the model is correct and feasible.Then, Analyzed and studied the dynamic mathematical model of asynchronous motor under different coordinate systems in-depth, and constructed the rotor flux oriented simulation module based on the MATLAB/Simulink; Adding vector control algorithm and then running the simulation model, the asynchronous motor in no-load starting and loading condition were discussed. It is proved that the vector control applied to the main propulsion motor is feasible.The last, Integrated all of model, included hull-propeller model, reducer model, Asynchronous motor model and vector control model, to establish the small ship electric propulsion system, based on a actual ship, the model is run in the classification and grading of reversing and starting the emergency brake condition.The simulation results show that the performance of asynchronous motor under vector control is better, especially at the beginning of operation, the current ripple and torque fluctuation amplitude is very small, under the condition of the control of propulsion motor speed stability, the electric propulsion system which have added the reducer can run smoothly, and motion state of ship is fine.