Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Structural Vibration Control of Offshore Wind Turbine Tower
Hailong Tian1, Xing Zheng1,*, Qingwei Ma2, Ziying Yu1, Hanbing Sun1
1. College of Shipbuilding Engineering, Harbin Engineering University, Harbin, China;
2. Schools of Mathematical, Computer Sciences & Engineering, City, University of London, London, UK;water depth, but also provide the possibility to make use of moreabundant offshore wind energy resources.

ABSTRACTThe load shedding control of offshore floating wind turbine(OFWT) under the action of wind and wave is studied. A three-degreeof-freedom model is established for a wind turbine with a tuned massdamper (TMD). The TMD parameters are optimized based on thestability of the control. In the structural load shedding control, theactive control using linear quadratic optimal control algorithm isselected. Active control can calculate the control force by monitoring
the movement of the tower in real time. The numerical simulation
results show that this method can effectively reduce the dynamic
response of OFWT compared with passive control.

One of the challenges faced by offshore floating wind turbines isthe platform pitching motion and tower bending deformation caused bywind and waves, which may lead to large displacement of tower top
and blade tip. These displacements will lead to considerable bending
moment and shear force at the bottom of tower and blade root, so as toreduce the fatigue life of structure, and even lead to catastrophic
damage of wind turbines under some extreme conditions. In addition,
the vibration of gearbox and generator installed in the nacelle leads to
the reduction of power generation capacity (He and Jin et al, 2019).
Therefore, load shedding technology is effective to improve the abilityof offshore floating wind turbine to bear dynamic load and generate
power. Load shedding means to reduce the platform pitching motion
and tower bending deformation caused by wind and waves by applying
a certain force to the wind turbine. A structural load shedding control isproposed in this paper.

KEY WORDS: offshore floating wind turbines; active control; tuned
mass damper

INTRODUCTION
In recent years, with the acceleration of global industrialization,
the demand for human electricity has increased significantly. However,the use of traditional energy for power generation not only seriously
pollutes the environment, but also is limited by the limitation of energy.
Therefore, people gradually turn their attention to new energy power
generation. As one of renewable energy, wind energy plays anattractive role in new energy power generation.

The paper is organized as follows: Section 2 introduces the threeforms of wind turbine structural control, including the control
principles, advantages and disadvantages. Section 3 introduces the windturbine model establishment process and the optimization of TMD
parameters. Section 4 describes the active control design. Section 5
verifies the effect of active control by FAST-SC simulation anddiscusses the results. Finally Section 6 discusses conclusions and futurework.

Traditional wind turbines are built on land, but due to limited land
resources and more abundant offshore wind energy resources, offshore
wind turbines came into being. According to whether the foundation ofoffshore wind turbine is fixed or not, it is divided into offshore fixedwind turbines (such as single pile and jacket type) and offshore floating
wind turbines (such as barge and tension leg type). Fixed wind turbines
are generally installed in shallow water (usually less than 60m). When
the water depth exceeds 60m, fixed wind turbines are not economicallyfeasible, and only floating wind turbines can be used (Leng and Yang etal, 2021). Floating wind turbines not only reduce the requirements for

STRUCTURAL CONTROL OF WIND TURBINE
The purpose of structural control is to reduce the vibration of thestructure, so as to reduce the load on the structure. Structural control
was initially developed in the field of civil engineering. In recent years,
structural control has been gradually applied to wind turbines. Its mainprinciple is to add a specific damper in the turbine nacelle or floating
foundation to dissipate energy through the reciprocating motion of the336