Research On The Parallel Hybrid Three-phase Four-wire Active Power Filter

In this thesis, the development of the methods of harmonic detection and the topology ofthe three-phase four-wire active power filter around the world are given, based on which, thetopology of the hybrid four-leg converter is put forward, and the principle and itscharacteristic are analysed. Then we analyse the application of the ip-iq harmonic detection inthe three-phase four-wire system. Based on the traditional method of acquiring the directcurrent by digital low pass filter, modified one of current average harmonic detectingapproach based on slip window is analysed. Their dynamic response and detection precisionin the symmetrical and dissymmetrical system are compared. Zero-order of fundamental andharmonic current, and specifically harmonic detection method is put forward, and thecorrectness of the method is proved through MATLAB simulation. As for the realization ofhigh-power three-phase four-wire hybrid active power filter, we produced parallel multiplemode, and the analyse of simulation proved that the mode can arrive at satisfying effect.