High-efficiency large-capacity uninterruptible power supply for 3-phase 4-wire power system

This paper discusses design and realization of multilevel uninterruptible power supply (UPS) for 3-phase 4-wire system by using bidirectional-switch-based three-level NPC multilevel power converter. The benefits of three-level topology for low voltage circuits are provided as a motivation for its application in UPS systems. As a result, the novel UPS features higher efficiency and effective size/weight reduction and hence aims to contribute to greening IT facilities with up-to-date power electronics technology.