Keywords

Acausal Modeling, Simulation, Controls, Wind Turbines, Control Co-Design

Abstract

The core objective of this research is to develop a comprehensive understanding of Floating Offshore Wind Turbines' (FOWTs') dynamic behavior and design robust control strategies to enhance their performance and reliability in offshore environments. This begins with a detailed dynamic model of FOWTs, accounting for complex interactions between the wind field and the turbine, leading to transient motions and structural loadings. The model's novelty lies in its use of an acausal modeling environment, facilitating reconfigurability, reuse, and plug-and-play features for Control Co-Design (CCD), where system design and control development occur in parallel, optimizing performance.

A significant contribution of this work is applying the Quantitative Feedback Theory (QFT) framework to FOWT control systems. QFT is a robust control methodology that enables the synthesis of controllers to accommodate uncertainties and disturbances. QFT-based controllers are designed to ensure stable and efficient FOWT operation under varying environmental conditions. Specific goals include reducing vibrational loads from blade root bending moments, tower fore-aft oscillations, and tower side-to-side oscillations, in addition to wind turbine speed control. The main actuations used are generator torque in addition to collective and individual blade pitch actuations.

To validate the proposed modeling and control strategies, comprehensive simulations are performed. The dynamic model of FOWTs is rigorously validated against industry-standard tools such as OpenFAST and experimental data from a prototype FOWT. This validation ensures the model's accuracy and reliability, providing confidence in its suitability for control system design and analysis. The validation process includes achieving accurate aerodynamic characteristics, joint force predictions, and blade pitch predictions during operation.

The findings of this research significantly advance floating offshore wind turbine technology. By enhancing the understanding of FOWT dynamics and providing robust control solutions, this work contributes to optimizing offshore wind energy generation, reducing the cost of energy production, and improving the sustainability of energy infrastructure.

Completion Date

2024

Semester

Summer

Committee Chair

Das, Tuhin

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Degree Program

Mechanical Engineering

Format

application/pdf

Identifier

DP0028871

URL

https://stars.library.ucf.edu/cgi/viewcontent.cgi?article=1377&context=etd2023

Language

English

Rights

In copyright

Release Date

February 2026

Length of Campus-only Access

1 year

Access Status

Doctoral Dissertation (Campus-only Access)

Campus Location

Orlando (Main) Campus

Accessibility Status

Meets minimum standards for ETDs/HUTs

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Restricted to the UCF community until February 2026; it will then be open access.

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