Four-branch star neutral current hybrid power filter and var compensator

This paper presents a solution for filtering current
\nharmonics in three-phase four-wire networks based on the usage
\nof a four-branch star (FBS) filter topology. The specific layout
\nof single-phase inductors and capacitors in this filter topology
\nallows achieving a power filter with two independent and
\nsimultaneous resonance frequencies, i.e., one for positive-
\n/negative-sequence and another one for zero-sequence
\ncomponents. The FBS filter topology can work either as a
\npassive filter, or as a hybrid filter, when its performance is
\nimproved by integrating a power converter into its structure.
\nThe paper analyzes the FBS topology and derives fundamental
\nconcepts about the control of a generic FBS hybrid power filter.
\nFrom this analysis, a neutral current hybrid power filter and
\nvar compensator is presented as an illustrative example
\napplying the FBS filtering topology to a three-phase four-wire
\nsystem. An evaluation using simulation and experimental results
\nis conducted as well.