A cascaded online uninterruptible power supply using reduced semiconductor

A cascaded online uninterruptible power supply (UPS) is proposed here that uses 25% lesser semiconductor, as compared to its traditional H-bridge cascaded precedence. Unlike other component-saving configurations where compromises are unavoidable, almost no performance degradations and constraints are experienced by the presented UPS, as guaranteed through proper topological and control design. Advantages of the cascaded UPS can therefore be summarized as reduced system cost, improved redundancy, better waveform quality and the same reliable protection expected from an online system. The only disadvantage, if considered so, is the requirement for slight logic manipulation of the switch gating signals, which in practice can simply be done by discrete logic gates without involving expensive programmable devices. Simulation results are presented to verify the discussed concepts.