Reduced Parts Three-Phase Series-Parallel UPS System with Active Filter Capabilities

In this paper, a new three-phase series-parallel line-interactive uninterruptible power supply (UPS) topology is presented. The new topology has less number of power electronic devices as well as control functions. Most of the power is supplied directly from the AC line to the load. Therefore, the overall efficiency is higher than that of on-line UPS. Different operating modes of the system and series and parallel converters are investigated as well. Simulation and experimental results are presented, which show the viability of the proposed topology.