Concepts of decoupled control for a shunt active filter based on multilevel current source converters

The shunt active filters are based on power converters driven to generate a current waveform injected in parallel to the system in order to compensate harmonics or to supply reactive power. Several topologies have been studied based either on voltage-source converters (VSC) or current-source converters (CSC), from the standpoint of power topologies and from the point of view of control strategies. The topology-based on a CSC has advantages especially in variable load operations, but the losses appear as a disadvantage. This work presents a shunt active filter based on a multilevel current source topology where the total DC link current is divided into each power module. The proposed control scheme solves the problem of the DC link current equalization typical of the current source multilevel topologies while minimizes the DC link conducting losses.