Pitch and Roll Motion Control of a Floating Wind Turbine With Hybrid Actuation

Platform stabilization and load reduction are of great importance for the successful development of floating offshore wind turbines. The increased degrees-of-freedom (DOF) for the relevant dynamics presents the challenge of underactuation. Recently, a tuned-mass damper (TMD) and active vane have been proposed to control the pitch and roll motions of a floating turbine platform. Simulations have indicated that TMD in the fore-aft (FA) direction cannot reduce the damage equivalent load (DEQL) for the side-to-side (SS) bending moment at the tower-base across all the loading conditions. In this study, the TMD in the FA direction is combined with an active vertical vane to reduce both the FA and SS platform motions and DEQLs. We refer to this combined system of actuation as the “hybrid actuation system”. The effectiveness of this hybrid scheme is demonstrated via simulations which are carried out in accordance with the IEC 61400-3 standard design load case 1.2–fatigue load testing.