| Based on AC-DC-AC frequency converter electric propelling system is the chief research orientation in the business and military marine development,which is of great practical and theoretical value to study the working state.The switch of propelling load operation mode will cause the power fluctuation of propelling system and marine electric power system,which the result of instability of the DC bus voltage.If the fluctuation of DC bus voltage exceeds a certain limit,damage may cause the accident of facility component and security.Meanwhile,as the rapid development of marine facility,much great power load is put into operation.Thus,much great power input in a short period of time is essential to guarantee the regular operation of high power impulse load.The traditional marine electric power system can’t meet the corresponding requirements,resulting in an instant power gap,without take appropriate measures,it is likely to cause a significant drop DC bus voltage.Considering two situations,above the relevant technology,that is,suppressing the DC bus voltage fluctuation based on the hybrid energy storage device is carried on it.A suppression method of DC bus voltage fluctuation is introduced in this paper.First,the typical topological structure of an electric propulsion ship is analyzed.The main electrical unit of mathematical and simulation model of electric propulsion ship are built,including AC-DC generator,propelling motor,propelling load and energy-storage module.The process of motor positive and reverse rotation and transient impulse mode are taken into analysis respectively based on the simulation model.It is analyzed about the basic theory and mathematical model of lithium iron phosphate battery and super-capacitor hybrid energy storage.The parameters of the PNGV model and the RC model of the lithium iron phosphate battery were modified appropriately and the simulation models are built respectively.What’s more,the charge and discharge characteristics were simulated and analyzed.Furthermore,the analysis of the control strategy of hybrid energy-storage system makes the precise control of power transfer by adopting a novel topology composed of lithium iron phosphate battery and super-capacitor combined with external system.Based on the hybrid energy-storage system including bi-directional DC/DC converter,multi-loop PI control and self-adaptation control strategy are designed to suppress the fluctuation of DC bus voltage.According to simulation results of different operation modes,the power storage capacity of different parts in hybrid energy storage system is initially calculated.According to MATLAB/Simulink simulation,the propelling system DC bus voltage fluctuation is analyzedin different power storage input conditions,positive and reverse conditions and impulse load input condition.Simulation results show that the proposed hybrid energy storage control method is capable of combining the advantages of two different power storage components,which can better suppress the system DC bus voltage fluctuation better.Finally,considering the characteristics of the DC bus voltage and the operating characteristics of the generator,the multi-objective optimization algorithm of the artificial bee colony is adopted in the system.And an optimization method is presented to improve the hybrid energy-storage capacity.Combining the simulation of the different working conditions of the system,it is verified about superiority of optimizing the hybrid energy storage capacity and the improvement effect of the optimization capacity of the DC bus voltage stability. |
PDF Full Text Request