A New On-Line Single-Phase to Three-Phase UPS Topology with Reduced Number of Switches

This paper presents design considerations and performance analysis of a new on-line single-phase to three-phase uninterruptible power supply (UPS) system with reduced number of switches. The proposed new UPS system consists of an integrated rectifier/boost converter with power factor correction (PFC) capabilities and a two-leg inverter connected to a split de-link bus. Two battery sets are directly connected to the de-link bus resulting in a very simple system. The proposed topology uses only 6 active switches reducing the cost of the system compared to the traditional 7, 8, and to-switch topologies. It has sinusoidal input current with unity power factor and high quality output voltages even with nonlinear loads. Detailed circuit operation and analysis as well as simulation and experimental results are presented.