Grid integration of offshore superconducting wind turbine generators

The recent technological trend for offshore wind power generation is toward multi-MW direct-drive units. Because conventional direct-drive generators tend to be large and heavy, high power density superconducting synchronous machines have been proposed. However such machines have unique requirements that must be satisfied for their correct operation and optimal grid integration. This paper investigates power electronic systems for superconducting wind turbine generators for offshore applications. First we consider special characteristics of superconducting machines, particular needs of offshore wind farms and grid regulations. Then we discuss the power converter topology, excitation system and wind farm connection with their associated control strategies. Finally we evaluate, by mean of simulation, the performances of a grid-connected 10 MW superconducting wind turbine generator with the adopted power electronics at startup, for sudden wind variations and during low-voltage ride-through.