Comparison of Parallel Connected Medium Voltage Grid Side VSCs for Offshore Wind Turbines

The goal of this paper is to compare different solutions for the parallelization of grid side voltage source converters operating in medium voltage for application in multi-megawatt (MW) offshore wind turbines. The study takes into account different alternatives in terms of both topology and modulation: in particular it considers whether the DC busses are common or separated, the output filters are isolated or coupled, and, in the latter case, the impact of the coupling coefficient value. The use of interleaving modulation technique is also analyzed. Systematic comparative analyses are reported with the goal of orienting trade off design choices for offshore converters.