PUC Converter Based on AC-DC-AC Multilevel Topologies with a Shared Leg

In this paper, two single-phase AC-DC-AC multilevel converter topologies based on Packed U-cell (PUC) and shared leg is investigated. The system consists of a four-leg module with a U-cell connected to the shared part of the system and a low-frequency transformer at the grid side. The first proposed topology can be used for applications where the output voltage is twice the grid voltage, and the second one is used for disturbance compensation in the power supply, like voltage swells. Compared to conventional four-leg topology, both proposed solutions can improve power quality and efficiency. The converters provide an input current with a high power factor and they feed the load with a stable voltage. System model, a space vector modulation, and a control scheme are shown to synthesize the input and output voltages of the converters. Simulation and experimental results are presented to confirm the feasibility of the proposed converter topologies as well as the correctness of the design methodology.