Mitigation of Third-Harmonic Voltage for Three-Phase Four-Wire Distribution System Based on a Series Active Filter for Neutral Conductor

摘要

This paper proposes a series active filter for mitigation of the third-harmonic voltage in a three-phase four-wire power distribution system in a building. The active filter which consists of a single-phase inverter can suppress the harmonic voltage of the system. The active filter is characterized by acting not only as a capacitor but also as a resistor for the third-harmonic components. A Hilbert transformer is applied to the controller of the active filter in order to realize accurate third-harmonic detection on a single-phase active filter. Measurement results of harmonic distortion of source voltage in a building is also shown in this paper. It is clarified in a simulation and experiment that the active filter can suppress the third-harmonic voltage without increasing neutral conductor current.