Active damping control of multi-mode UPS for power quality improvement

Double-conversion UPS provide top protection to critical loads, but limited efficiency. However, such UPS often support alternative high-efficiency operating modes (e.g. so-called ECO Mode). This paper discusses Active ECO Mode operation, introducing Active Damping Control for improving Power Quality with minimal losses. The system evolves into a Multi-Mode UPS, where the operating mode is selected for optimal trade-off between power conditioning and efficiency. Performance improvement is confirmed by experimental results and field experience.