Topology and control analysis of single-DC-source five-level packed U-cell inverter (PUC5)

This paper presents a thorough study on Five-Level Packed U-Cell inverter called PUC5. The main advantage of PUC5 topology over other popular multilevel ones is the redundant switching states, which facilitate the voltage balancing of the flying capacitor in its configuration. Switching states of the PUC5 inverter are analyzed to ensure an easy voltage balancing process. That voltage controlled auxiliary capacitor helps generating five identical voltage levels at the output using a single DC source. A full comparison is done to other 5-level inverter topologies to reveal the dominant features of the PUC5 structure. Moreover, some discussion on the controller design for the PUC5 inverter is conducted in grid-connected applications which indicates similar procedure performed for conventional 2-level ones due to featuring single-dc-source configuration. Various experimental results are shown in each discussion for better understanding.