Direct Individual-Phase Reactive Current Control Method for an Active Power-Line Conditioner in Three-Phase Four-Wire Distribution Feeders

This study proposes a new direct individual-phase reactive current control method that can suppress the neutral-line current for an active power-line conditioner in three-phase four-wire low-voltage distribution feeders. When the reactive currents are individually controlled with harmonics compensation, the sinusoidal and unbalanced source currents are obtained. This results in a large neutral-line current on the source side. This paper suggests the redistribution of the active components on the source side to suppress the large neutral-line current. The basic principle of the proposed active-component redistribution is discussed in detail and was confirmed by digital computer simulation. A laboratory-scale experimental setup was built and verified. Simulation and experimental results prove that the proposed direct individual-phase reactive current control method achieves sinusoidal and unbalanced source currents with the suppressed neutral-line current.