The Research On Harmonic Analysis And Cuppression Methed Of AC Electric Propulsion Ship Power Grid Power Grid

With the development of power conversion technology,the AC power propulsion ship based on power conversion becomes one of electric propulsion technology researches.But wide usage of power conversion devices,especially the application of propulsion systems for ships grid also brings increasing prominent harmonics,which directly affects the quality of power supply and economic performance of the ship power grid.Therefore,research of AC electric propulsion ship harmonic analysis and suppression methods have important value.In order to realize the AC electric propulsion ship power system analysis of harmonic and research of suppression methods,In this paper,the main module harmonic Principle of the AC electric propulsion ship harmonic will be analyzed and the simulation model of a ty pical AC electrical propulsion system will be built to research harmonic.Combined with t he characteristics of the AC electric propulsion ship,the two commonly methods of harmo-nic analysis were compared.Through the analysis conclusion about different nodes voltage harmonic,the simple and practical method of fast Fourier analysis will be used as the harmo-nicanalys is method of this paper.The application of three kinds of harmonic suppression schemes in AC electric propulsion ships has been studied,including the harmonic control scheme based on multi-pulse rectifiers,the harmonic suppression scheme based on shunt active power filters and series active power filters.12 pulse,24 pulse form were adopted by multi pulse rectifier device respectively,the vector control and the feed-forward decoupling control were adopted by shunt active power filter,and the voltage feed forward control were adopted series active power filter.According to the simulation results and the requirements of the harmonic in the AC power propulsion ship,the problem of the applicability for various suppression methods was investigated,which means that the corresponding harmonic suppression scheme was given out under different ship energy quality requirements.In addition,combining with the theory of grid virtual flux orientation angle for active power filter,an improved i_p-i_q harmonic detection method was put forward according to the disadv antages of traditional method which's disadvantages were studied to impoove-through the active power filter based on Grid virtual flux orientation angle theory.Regarding the harmonic compensation performance of active power filter as the optimization goal to achieve better effect of suppressing harmonics,the parameter optimization design scheme based on genetic algorithm has been adopted to optimize the RLC parameters of series active power filter's output filter circuit.By restricting the threshold of fitness function and selecting chromosome with different probability,the population made the evolution towards the direction of optimal coordination point in power filter.Finally,the simulation results of AC electric propulsion ship simulation model showed that the designed RLC parameter based on genetic algorithm had better performance for series connection active power filters.