Multifunctional study of single-phase ups with current fed full-bridge converter

A novel single-phase current fed full-bridge converter with split DC output voltage, multifunctional input source (main grid, photovoltaic modules or battery bank), power factor correction for main grid applications and high-frequency transformer (HFT) isolation topology is presented in this paper. This converter might be a suitable alternative when used as an input stage of uninterruptible power systems (UPSs) compared to large conventional UPSs that are based upon bulky transformers that operate at the grid frequency, and due to the increasing interest in renewable energy integration and distributed generation (DG), it can also be a suitable solution for energy storage in microgrids or renewable-power-conditioning interface applications. The main features are soft commutation of the controlled switches, reduced weight and volume of magnetics, simple control strategy that can be implemented with well-know integrated circuits, use of a few batteries in series due to the same reference of the step-up stage, and connection between input and output enabling by-pass. A theoretical analysis, the implemented control strategy and the simulation results for main grid and photovoltaic solar energy applications obtained from an 1-kVA lab model are presented.