An uninterruptible power supply (UPS) system provides backup power supply for an application in the event of an electrical outage. Several basic topologies exist, differentiated by function during a power outage. The development process of all is concerned with unit efficiency, cost performance, operability, maintainability and safety. This paper describes a model of on-line UPS with modified boost converter, ie to improve the boost converter efficiency, soft-switching technologies using an active and a passive method have been developed. The soft-switching topologies using the passive methods have advantages, such as high reliability and the simplicity of both power circuit and control compared to the active methods. The proposed converter uses a passive snubber to recover the snubber energy into the output. Simulation results are analysed in this paper to illustrate performance differences of a boost converter with and without regenerative snubber and conventional, modified UPS systems.

Key words: Boost Converter, DC-DC Converter, Uninterruptible Power Supply, Regenerative Snubber, Soft-switching, Passive Snubber.