A Soft-Switching Single-Phase Two-Arm Unified Power Quality Conditioner

This paper presents a single-phase two-arm soft-switching unified power quality conditioner (UPQC). This paper deals with a novel soft-switching unified power quality conditioner, which aims at the integration of a soft-switching series-active and a soft-switching shunt-active filter. The proposed soft-switching UPQC employs a two-arm topology and uses simple resonant units. All main switches operate at zero-voltage-switching (ZVS) turn-on, while the auxiliary switches operate at zero-current-switching (ZCS) turn-off. Rather than the conventional topology, the proposed two-arm topology not only reduces the number of power switches but also increases the system reliability and simplifies the control circuits. The proposed soft-switching series power filter can compensate for the AC source voltage fluctuation. It can be used to regulate the under-voltage and voltage harmonic situations. The proposed soft-switching shunt power filter can compensate for the current harmonic and improve the power factor. Some experimental results of the proposed UPQC are presented for verification.