Floating wind turbine control using fictitious force decoupling

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Sivakumar, Nitin and Recalde-Camacho, Luis and Leithead, William E. and Hur, Sung-Ho (2026) Floating wind turbine control using fictitious force decoupling. Ocean Engineering, 352 (Part 1). 124489. ISSN 0029-8018 (https://doi.org/10.1016/j.oceaneng.2026.124489)

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Abstract

Floating wind turbines present control challenges absent in bottom-fixed systems. Platform motion excites low-frequency rigid-body modes within the operational bandwidth of standard controllers. This interaction generates right-half-plane zeros in the pitch (input) to generator speed (output) dynamics near the platform’s natural frequency, reducing phase margin and limiting achievable bandwidth. This study proposes a fictitious force-based decoupling control framework that reformulates turbine dynamics in a non-inertial nacelle-attached reference frame. In this frame, accelerations due to platform motion appear as fictitious forces that impair control performance. To mitigate their effect, an additive correction, corresponding to the fictitious forces, is applied to the measured generator speed used by a conventional bottom-fixed controller. This decoupling prevents the controller from reacting to platform-induced motion, which would otherwise degrade control performance. The fictitious forces are estimated from nacelle acceleration measurements and three fictitious-force models of different complexity, introduced in this paper. They are then augmented to the measured generator speed, enabling the direct reuse of bottom-fixed controllers without retuning. The approach is assessed using a high-fidelity aeroelastic model of a 5 MW reference turbine, and results demonstrate that the proposed strategy suppresses platform motion and tower loads, while maintaining speed regulation comparable to the bottom-fixed case.

ORCID iDs

Sivakumar, Nitin, Recalde-Camacho, Luis ORCID logoORCID: https://orcid.org/0000-0002-3911-2857, Leithead, William E. and Hur, Sung-Ho ORCID logoORCID: https://orcid.org/0000-0002-9263-1584;
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