Research On Harmonic Suppression In Microgrid

In recent years,with the development of new energy power generation technology,microgrid has been developed rapidly as an effective way to improve the efficiency of the comprehensive utilization of new energy.However,in the microgrid,due to the use of a large number of power electronic switching devices and intermittent,unstable characteristics of the micro power supply,resulting in serious harmonic problems in the microgrid.In order to improve the power quality of microgrid and ensure its safe and reliable power transmission,this paper has practical significance and application value for the mechanism of harmonic generation and the research of harmonic control device active power filter.In this paper,the basic structure of microgrid and mechanism of harmonic generation are studied in depth.The characteristics of the harmonic in the microgrid system are analyzed in detail.Based on this,a harmonic passive control device,active power filter,is selected.Then,p-q harmonic detection algorithm and i_p-i_q harmonic detection operation method which are based on reactive power instantaneous theory are analyzed theoretically.Combined with the characteristics of micro grid voltage distortion and harmonic complexity,it is concluded that the p-q algorithm and i_p-i_q algorithm have certain limitations.Then an improved harmonic detection method based on i_p-i_q method is proposed.Simulation analysis shows that the improved harmonic detection method is suitable for harmonic detection in microgrid.It provides theoretical basis for comprehensive harmonic control.Then,simulation model of the shunt active filter is built in Matalab/Simulink,and simulation experiment is carried out on the harmonic suppression method of microgrid.The compensation performance of active power filter and dynamic tracking performance of shunt active power filter in microgrid environment are analyzed and compared under the action of PI control and PI+repetitive control.Finally,simulation proves that the active filter has good harmonic compensation effect on the basis of the improved detection method.