A novel topology for single phase UPS systems

A novel converter topology suitable for on-line single-phase UPS systems is presented. The converter, based on an AC-DC/DC-DC boost converter combined with a half bridge inverter, uses only five active switches to realize very desirable features. These include sinusoidal input currents, a common neutral connection-eliminating the requirement of an isolation transformer, capability of voltage balancing control for DC bus capacitors, low voltage storage battery as well as its charge or discharge regulations. Further, voltage stresses on the switches in the boost converter are greatly reduced, compared with conventional half bridge converters. Detailed simulation results and experimental results are included in this paper.