Harmonic Simulation And Suppression Of Polar Ship Electric Propulsion System

With the rapid development of power electronics technology,electric propulsion technology has been widely used in ships.However,a large number of frequency conversion equipment and nonlinear load are used in the electric propulsion system,which results in a large number of harmonics in the ship power grid,affecting power quality and navigation safety of the ship.So far inland and oversea,the harmonic of electric propulsion system simulation research focused on the 6-pulse,12-pulse rectifier circuit simulation,involves24-pulse rectifier circuit simulation study is less,in the practical application of Marine engineering,harmonic governance is more of a multi pulse rectifier technology and the active filtering technique combined with integrated solution,in order to achieve the best balance between harmonic suppression effect and economic investment,this article through to ship electric propulsion system adopts the virtual 24-pulse rectifier circuit and active filter harmonic suppression scheme of combining simulation modeling,simulation results compared with testing result measured harmonic data analysis,Verify the effectiveness of the proposed harmonic suppression scheme.The simulation study has important guiding significance for the engineering application design of ship electric propulsion system,and provides engineering practice for how to control harmonics in ship power grid,which has certain reference significance for ensuring the power quality and safety of the ship.Based on the power system of the 44500 DWT ice breaking condensate taker as the research object,through the power system,the power equipment for modeling and simulation,and combined with testing result of harmonic measurement in sea trial data were analyzed: first of all,this paper introduces the principle of power system harmonic and several commonly used ways to restrain the harmonics and harmonic calculation.Second,the way of modeling and simulation based on Matlab,the testing result of 3 kinds of operation mode of power network various power equipment simulation,modeling,calculation,it is concluded that the various operating modes of the system THD(Total Harmonic Distortion),at the same time combined with testing result in three kinds of sea trial mode in measurement of harmonic data comparative analysis,to verify the effectiveness of the testing result by using virtual 24-pulse polyphase rectifier circuit and active filter in Harmonic suppression effectiveness.Finally,the paper further introduces the measures to prevent electromagnetic interference of ships,and analyzes the rationality and necessity of adopting these measures to promote ships by electric power.Through the research and simulation analysis in this paper,the simulation models of ship operation conditions in three modes are established.Under the operation conditions of mode 1 and mode 2,the power grid adopts virtual 24-pulse rectification as the main harmonic suppression method,and the THD can be reduced to 2.7%.Under the operation condition of mode 3,THD can be reduced to 1% under the rectifying suppression effect of active filter.The correctness of the simulation data is verified through the measurement of real ship harmonics,which provides theoretical basis for the subsequent ship design synthesis and effective control of harmonics and anti-electromagnetic interference.