The best suitable multilevel converters for offshore wind power generators without transformers

Offshore wind farms are facing challenges which call for redesigning the electrical drive train of future wind turbines. The turbines are expected to increase in power, and plans for 10-15 MW wind turbines have been reported. Hence will a medium-to high voltage converter solution be highly beneficial. Additionally, a DC-distribution grid is discussed for offshore applications. This indicates that the applied converter should have highly controllable DC-output. Also, the converter should include fault redundancy, as the availability for maintenance is limited. Based on the constraints imposed by the application, this paper evaluates which type of converter is the most suitable for offshore wind turbines.