Five-level H-bridge NPC central photovoltaic inverter with open-end winding grid connection

This investigation presents a grid-connected five-level H-bridge neutral-point-clamped converter operating with a single dc-link as photovoltaic power source. The operation with a single dc-bus is enabled by adding a transformer with open-end winding secondary, where each power cell of the converter is connected. The proposed control scheme is validated trough simulation results and tested under dynamic conditions. It can be implemented with a good tracking of the active and reactive power references injected to the grid. The results serve as a preliminary validation to potential utilization of the converter in large scale photovoltaic energy conversion systems.