Consequences of load mitigation control strategies for a floating wind turbine

Several approaches to avoid control-induced resonances of floating wind turbines have been proposed. The main focus has been on reductions in global motions and loads in the tower base. In the present work, we examine the consequences of three such controllers on the loads on drivetrain components. One common advantage that comes along implementing all the alternative controller designs is an improved motion response in surge and pitch directions. However, these reductions come at other costs. Evaluating the drivetrain performance through multi-body simulations identifies new considerations for controller design. For example, tower top shear stress may not have been perceived as an important design criteria from a structural load perspective, but contributes to the radial load of bearings and gears and should be taken into consideration when comparing controller performance.