Power stage arrangement for high power single-phase input and single-phase output online UPS

Online UPS stands the high power extreme that reaches the capacity limitation of ordinary commercial single-phase utility. The consequent high current requires special management in the power stage other than those routine low power structures, to achieve reduced loss, heat and more reliability. With overviews upon competitive schemes, the specified PFC front end is to be investigated as an outstanding configuration, possessing the least parts number and conduction dissipation. What´s more, circuit optimization and cost reduction play important roles in products design once the functions are accomplished. A unified rectifier-battery discharger is proposed. This DC bus voltage supplier employs nothing extra but a few cheap components more than the conventional PF corrector. On the other hand, high switching frequency is demanded for acoustic noise elimination and weight/volume reduction. Switching aid methods in circuit topology do work on relaxation and/or transfer of electric stress and loss from the main power switches. Performance comparisons are examined over snubberless and series current choked operations respectively, especially on a full bridge inverter. Topology detail, qualitative and quantitative descriptions, parameter design, topological and simulated analysis, are presented in the R&D process for a 5 kVA UPS.