Integrated IPC-TMDI control for mitigating fatigue in floating offshore wind turbines under misaligned wind-wave loading

Abstract

As floating offshore wind turbines (FOWTs) increase in size, they become more efficient but also more susceptible to vibrations and fatigue, shortening their lifespan and reducing power generation. Existing control strategies often address these loads in isolation, limiting their effectiveness. This study proposes a cooperative control approach combining individual pitch control (IPC) with a side-to-side tuned mass damper inerter (TMDI) to mitigate tower fatigue under wind-wave misalignment. A multi-body dynamic model integrates a tower-top TMDI and a reduced-order IPC with an LQ controller to evaluate FOWT responses. Simulations of various wind-wave misalignment scenarios demonstrate that the cooperative approach significantly reduces fatigue damage equivalent loads (DELs) and stresses (DESs), extending tower fatigue life, particularly in high misalignment conditions.