On-line Assessment of Voltage Quality in Multi-Mode Operation of Double-conversion UPS

Double-conversion is the preferred UPS topology for protecting sensitive loads. Multi-mode UPS (maximizing efficiency while preserving power quality) are an established alternative, requiring assessment of voltage quality and particularly voltage distortion. This paper proposes a technique for estimating distortion and detecting events compromising voltage quality. The theoretical analysis is complemented by simulation and experimental result from high-power Multi-mode UPS systems.