Uninterrupted power supply based on a new transformerless integrated power converter

This paper proposes an on-line transformerless UPS system based on the integrated power electronics converters that is able to control the input power factor, charge the battery, and guarantee backup operation in the case of utility power outage. The main advantages of the proposed UPS are: 1) active power factor correction (PFC) without any feedback control, and 2) integrated functions of the battery charger circuit and PFC by using only three power switches. Details regarding the operation modes of the system and modulation strategy are presented. Simulation results are presented to validate the theoretical expectations.