Modeling and Control Co-Design of a Floating Offshore Vertical-Axis Wind Turbine System

Abstract This study investigates the modeling and design of a floating vertical-axis wind turbine (FloatVAWT) system with multidisciplinary design optimization (MDO) and control co-design (CCD) approaches. By integrating various associated disciplinary models, the study aims to holistically optimize the physical and control designs of the FloatVAWT system. Through the identification of impactful design elements and capitalizing on synergistic interactions, the study aims to provide insights to subsystem designers and aid their detailed decisions. The model developed for this CCD framework utilizes automated geometric manipulation and mesh generation to explore various FloatVAWT configurations during the early design stages. Surrogate models facilitate efficient design studies within limited computing resources by exchanging model information between disciplinary models and subsystems without running exhaustive simulations during the optimization loop. The model incorporates an aero-hydro-servo dynamic representation of the FloatVAWT system, considering physical and control constraints. Additionally, the study investigates the potential benefits of varying the average rotational speed of the vertical-axis wind turbine (VAWT) rotor to enhance energy production and minimize adverse platform motions, thus reducing the levelized cost of energy (LCOE). System-level design solutions are analyzed to identify design trade-offs and propose mitigation strategies for potential mechanical failures of the rotor. In conclusion, this study provides modeling strategies for the FloatVAWT system and analyzes the system design solutions through MDO and CCD approaches. The outcomes of the study offer insights into system-optimal solutions for subsystem-level decisions considering multidisciplinary couplings.