Design And Steady-state Analysis Of Ship Medium Voltage DC Integrated Electric Propulsion System

With the rapid consumption of fossil fuels and the vigorous development of ship,scholars all over the world are studying how to build a ship with high power density,high operating efficiency and high operational flexibility under the premise of comprehensive utilization of energy and energy efficiency.The proposal of ship medium voltage DC integrated electric power propulsion system points out the development direction of ship integrated electric propulsion system.To reuse DC power system in the ship integrated electric propulsion system does not simply mean to return back to the DC power supply system,it means to use both the advantages of direct current alternating current to form a more complete and reasonable ship power system structure.So that it will be able to achieve the purposes,such as saving space and energy,extending equipment life and so on.At present,not only the study of DC integrated electric propulsion system itself,such as system design,system transient and steady-state characteristics,system stability,has become a prominent research site.But also the theoretical issues which may exist in the system,such as DC circuit breaker design,DC current protection device design research,have attract the attention of domestic and foreign scholars and experts.For the ship medium voltage DC integrated electric propulsion system which attracts much attention,the source design,the structure design and steady-state analysis are studied.In order to carry out the source design,the 146 m deck parameters are first sorted out.Based on the analysis of the load data,the coefficient method is selected as the calculation method.Through the ship design manual and reference literature,the principle of the number and capacity of generator sets is determined.Then the source design is studied against the improved load parameters.In the structure design,firstly the paper studies the composition of the ship medium voltage DC integrated electric propulsion system.After that,the three typical structures proposed by domestic and foreign scholars are expounded and analyzed.Finally,combining with the basic principles of structure design and the power supply design results to complete the structure design.Steady-state analysis is mainly based on the power flow calculation.Since the ship medium voltage DC integrated electric propulsion system is a hybrid electric power system,the ship power flow methods,such as forward push back method,node potential method,are not practical any more.In this paper,firstly mathematical models of DC/DC converters,AC/DC inverters and cables are established.Then the DC Newton Raphson method and the DC stratified push back method are improved to be the power flow calculation method used in the ship medium voltage DC integrated electric propulsion system.Finally the experimental analysis under different conditions and convergence conditions and the comparison between the two methods are carried out.The result not only verifies the rationality of power supply design and structural design but also proves the feasibility of the algorithm.