A novel four-branches-inverter-based-active-filter for harmonic suppression and reactive compensation of an unbalanced three-phase four-wires electrical distribution systems, feeding AC/DC loads

This paper deals with the design, analysis and digital simulation of a novel four-branches-inverter-based-active-filter, that compensates the reactive power and suppress the harmonic currents in the phases and neutral of an unbalanced three-phase four-wires electrical distribution system, feeding AC/DC loads. That is, the filter has the capability to instantaneously suppress the harmonics currents, in both the three-phases and the neutral, white simultaneously compensating the reactive power in each one of the unbalanced three-phases, bringing their respective power factor to unity. The novelty of the active filter resides in the use of a four-branch DC/AC inverter acting as the main active compensator. Three branches are needed to compensate the three phase currents and one-branch compensates the neutral current. A number of selected simulation results proves a superior performance of this filter when the loads are three one-phase rectifiers in one case, and one 3-phase converter with a one-phase rectifier in the other.