Modeling And Stability Analysis For Marine Electrical Propulsion System

Electric propulsion system is a new type of marine power system,as the technological innovation and research become more and more deep,the world field of marine electric propulsion is struggled to make further improvement on marine mobility,reduce marine noise properties.For the research on marine electric propulsion technology started relatively late in China,there are still more problems in the process of applying theoretical achievements to actual ship.Therefore,it is very necessary to model,simulate and analyze for marine electric propulsion system.This research get the whole model through modeling,simulation and analysis for each module of marine electric propulsion system,and then carries on the preliminary simulation research on its transient stability.This thesis adopted the modularization ideas,divided the electric propulsion system into prime mover and speed-control system,generator and excitation system,propulsion motor and frequency conversion control system,propeller and the other parts,respectively analyzed the working principle and mathematical model,and then established system's simulation model: first of all,it set up the simulation model of diesel engine and speed-control system,the simulation model of generator and excitation system respectively,and then combined two parts into generator unit in accordance with the relevant principles,meanwhile,adopted static load model represent the ship's daily load,and then combined with generating unit to constitute the electric power system.The accuracy of simulation model proved by suddenly loading and unloading high power load simulation and experiments,and analyzed the transient stability according to the performance index of CCS "Classification Rules of Steel Sea-going Vessel",Then analyzed the id=0 control thought of the permanent magnet synchronous motor,adopted the vector control method based on current hysteresis,designed the simulation model of propulsion motors and frequency control of motor speed system;single neuron adaptive control algorithm was analyzed to design single neuron adaptive PID controller to replace the traditional PI speed controller,through compare analysis of simulation results,verified the improvement of the system stability with the new controller.Then analyzed the mathematical model of the propeller,combined with the mathematical model of the ship-paddle,set up the corresponding simulation model,verifed the improvement of indirect-startup on the system stability through the comparison of simulation results under two kinds of startup mode.At last,each component of marine electric propulsion system was assembled,the thesis further analyzed the indirect-startup was more better than the direct-startup for system's transient stability,and verified the reliability and stability of themodels of marine electric propulsion system.