Open-Loop Control Co-Design of Semisubmersible Floating Offshore Wind Turbines using Linear Parameter-Varying Models

TL;DR

This paper presents an integrated control co-design framework for floating offshore wind turbines using linear parameter-varying models to optimize plant and control system design for improved power and stability.

Contribution

It introduces a novel low-fidelity modeling approach combined with open-loop control trajectories for co-design of plant and control variables in floating wind turbines.

Findings

Plant design impacts power production and stability.

Control decisions influence cost of energy.

Platform stability is affected by design choices.

Abstract

This paper discusses a framework to design elements of the plant and control systems for floating offshore wind turbines in an integrated manner using linear parameter-varying models. Multiple linearized models derived from aeroelastic simulation software in different operating regions characterized by the incoming wind speed are combined to construct an approximate low-fidelity model of the system. The combined model is then used to generate open-loop, optimal control trajectories as part of a nested control co-design strategy that explores the system's power production and stability using the platform pitch tilt as a proxy in the context of crucial plant and control design decisions. The radial distance between the central and outer columns and the diameter of the outer columns of the semisubmersible platform are the plant design variables. The platform stability and power production are studied for different plant design decisions. The effect of plant decisions on subsequent power production and stability response of the floating wind turbine is quantified in terms of the levelized cost of energy. The results show that the inner-loop constraints and the plant design decisions affect the turbine's power and, subsequently, the cost of the system.