Medium Voltage Multilevel Converters for a Multi-MW Wind Turbine Grid Connection

Abstract– Recent advances in the wind power technology have increased wind turbine power ratings to multi-MWs. This increase and recently introduced strict grid codes are spurring the utilization of full-scale medium voltage (MV) grid-side power electronics converters in wind turbines. In this study, for the grid connection of a hypothetical 6MW-3kV wind turbine, three-level (3L) configurations of NPC, FC, and HB VSCs are simulated for PF=0.9-1 and fc=650-1050Hz. The simulation results show their performance with respect to total harmonic distortion of current, switch utilization, switch losses, and loss distribution. Finally, these VSCs are compared with respect to the two most important criteria (power density and reliability) for the 6 MW wind turbine connected to a MV (>3kV) grid via a transformer.