Individual-Phase Displacement Power Factor Control Strategy of an Active Power-Line Conditioner in Three-Phase Four-Wire Distribution Feeders

This article proposes a novel individual-phase displacement power factor (DPF) control strategy with a suppressed neutral-line current for an active power-line conditioner in three-phase four-wire distribution feeders. The reference source currents are calculated using the fundamental active component of the load currents, which is calculated using a constant DC-capacitor voltage control block. The compensated source-side currents are sinusoidal, but unbalanced because the active currents of the source-side currents are unbalanced. These unbalanced active currents suppress the neutral-line current to achieve a predetermined DPF in each phase. A digital computer simulation is implemented to demonstrate the validity and high practicability of the proposed individual-phase DPF control strategy, and a reduced-scale laboratory model is developed and tested. Simulation and experimental results verify that the proposed individual-phase DPF control strategy attains sinusoidal and unbalanced source currents with a predetermined DPF in each phase suppressing the neutral-line current.