A Three-Level Isolated AC-DC PFC Power Converter Topology with a Reduced Number of Switches

The main objective of this research work is to develop a new low-cost isolated three-level ac-dc power converter topology with a reduced number of switches. Existing three-level converter topologies change ac power to dc power while maintaining requirements set by international standards for power conversion. These types of converters have significant conduction losses due to high currents in the low-voltage side and high costs, mainly when using several active devices in series or in parallel to achieve high-voltage and high-power levels. The proposed topology replaces the conventional three-level converters in the secondary side by only two controlled devices and four diodes while still maintaining the basic functionality of a three-level converter. Furthermore, simulation results for a 25-kW case study and experimental results on a 900-W scale-down prototype demonstrate the feasibility of the proposed ideas.