Back-to-Back Active Power Filter for Current Balancing in Two-Phase Systems

The use of a second phase in household electric wiring is a requirement for feeding heavy loads in those countries using 100 ~ 127 Vrms as the standard voltage. One problem of this wiring is the unbalance between phase currents since single-and two-phase loads coexist. A back-to-back topology is proposed for an active power filter to add it the ability of active power compensation. The presented topology uses the same number of hardware components of others proposed topologies that just are able of reactive power compensation. The system is tested implementing a predictive direct current control when is connected to two different two-phase systems: those obtained by taking two phases of a three-phase system (120° between phases) and for two phases obtained from a split-phase transformer secondary (180° between phases).