The Simulation Study On Propeller Load Characteristics Of Marine Electrical Propulsion System

With the great development of the electric semiconductor technology, the frequency control technology and the microcomputer control technology, the technology of ship electrical propulsion has been widely used in recent years. The electrical propulsion has become the new development direction of modern ship propulsion types by its many superiority. The propeller takes much important place in the electrical propulsion system. Therefore, it is very necessary to research the propeller load characteristics for further understanding electrical propulsion system. The subject supported by the fund of "laboratory of marine electrical propulsion simulation system" from Wuhan University of Technology has made the research and analysis on the propeller load characteristics through the simulation experiments.The thesis takes propeller load as the research object. And the ship and propeller are regarded as a whole. The paper develops a set of simulation model of propeller load for marine electrical propulsion simulation system in the laboratory, thus provides accurate shaft load for propulsion motor and simulates the marine propeller working characteristics under different conditions of ship. The following is main work in the thesis.1. This paper introduces the working principle of propeller, propeller's characteristic curve, and the interaction between propeller and ship. Three kinds of typical characteristics of propeller and ship resistance characteristics are analyzed.2. In order to simulate propeller load, this paper selects advance coefficient of the bounded mode and the test atlas of Nordstrom series and adopts the fitting method of Chebyshev polynomial. The thrust coefficient and torque coefficient can be adjusted according to different numbers of propeller blades and area ratio.3. In order to simulate dynamic load characters by laboratory's equipment, the paper sets up the machine motion balance equations and analyses the ratio of the torque and moment of inertia between laboratory'equipment and real ship. 4. Those mathematic models are described by the components in Saber library and Mast language. Then the propeller load model is simulated and analyzed.5. The co-simulation with Saber and Matlab/Simulink has been preliminarily studied. The interface problem is realized.6. Comparing with the law of ship maneuvering and motion, the simulation results show that the whole ship-propeller simulation model can well simulate the working state of the practical propeller load with good precision. The results can provide the theoretical prediction and analysis.