Drive-train configurations for Floating wind turbines

Designing an offshore floating wind turbine brings new structural and mechanical constraints to the nacelle and its components. For the purpose of stability and avoiding critical eigen frequencies for the tower, the tower top mass must not be too high. Because of the transient nature of loads acting at the nacelle and high probability of mechanical failure, the strength and the life of components are at stake. This implies that the components at the nacelle must have a simple design with fewer parts, be lightweight as practically possible and also strong enough to cope with the load dynamics. A survey on some of the floating wind turbine concepts shows that geared driven power trains are the standard design choice. This article identifies some key attributes that are essential for drive-trains to be successfully integrated onto floating wind turbines. An Overview of technology options is presented with a comparative assessment on their suitability to floating wind turbines based on their simplicity, structural integrity and potential for weight reductions. With a number of methods available for weight optimized construction and greater flexibility in design, direct-drive generators appear to be a promising option for floating wind turbines.