Compensation of Harmonics in Neutral Current Using Active Power Filter for Three Phase Four Wire System.

Increased penetration of nonlinear loads like power electronic converter based systems have aggravated issue of harmonic injection in the power system. Neutral current harmonics is an issue of concern for three phase four wire system. This paper is focused on the elimination of neutral current harmonics with the help of shunt active power filter based on the star-delta transformer and single phase half bridge inverter. The presented active power filter eliminates harmonics present in neutral current which in turn helps in mitigating third harmonics from the supply mains. The topology has the advantage of reduced number of semiconducting devices and switching losses as compared to conventional three phase active filter. Simulation studies for the proposed active filter are presented and compared with the behavior of conventional three phase active filter. Experimental results for DSP based laboratory prototype of the proposed filter are shown to substantiate performance of system. Both simulations, as well as experimental results, demonstrate effective compensation provided by single phase half bridge inverter based active filter. [ABSTRACT FROM AUTHOR]