Offshore wind turbine simulation: Multibody drive train. Back-to-back NPC (neutral point clamped) converters. Fractional-order control

This paper is on offshore wind energy conversion systems installed on the deep water and equipped with back-to-back neutral point clamped full-power converter, permanent magnet synchronous generator with an AC link. The model for the drive train is a five-mass model which incorporates the dynamic of the structure and the tower in order to emulate the effect of the moving surface. A three-level converter and a four-level converter are the two options with a fractional-order control strategy considered to equip the conversion system. Simulation studies are carried out to assess the quality of the energy injected into the electric grid. Finally, conclusions are presented. •Offshore variable-speed wind turbine in deep water.•Drive train is a five-mass model takes in consideration the effects of the moving floating surface.•Converter topologies considered are three-level and four-level ones.•Controllers are based on fractional-order methods.•Assess the quality of the energy injected into the electric grid.