Control concept of Unified Power Line Conditioner

The Unified Power Line Conditioner (UPLC) with integrated series and parallel active filters is a universal solution featuring most power quality problems in distribution systems. This paper outlines the central concept of UPLC. The series active filter is controlled to maintain the load terminal voltage at required level with sinusoidal waveform, while the parallel active filter is specialized for mitigating the harmonics and the imbalance of the nonlinear loads. The exchanging power between the two active filters is limited to minimum. The control concept of UPLC is introduced and analyzed, with the simulation results to demonstrate the proposed approach.