The increased size and flexibility of modern multi-Megawatt wind turbines has resulted in the dynamic behaviour of these structures becoming an important design consideration. The aim of this paper is to study the variation in natural frequency of wind turbine blades due to centrifugal stiffening and the potential use of semi-active tuned mass dampers (STMDs) in reducing vibrations in the flapw...

Offshore wind turbines have been installed in increasing water depths over the last years. Support structures with monopile or gravity based foundation could successfully be used for all realized offshore-projects, but the trend of increasing water depths reached a level that makes application of those relatively simple types of support structures inappropriate. New concepts like tripods or lat...

This paper presents a new methodology for controlling wind farms in a decentralized framework, where the wind turbines exchange information with their neighbours, and update their own control parameters in order to optimize the total power produced by the wind farm in a time-efficient manner, taking into account effects of wake interaction. The method can be characterized as being model-free si...

This study entailed a load evaluation for the tower design of large floating offshore wind turbine system in accordance with wave conditions. The target model includes IEA 15 MW reference and semi-submersible VolturnUS-S platform from University Maine. OpenFAST, which is an aero-hydro-servo-elastic fully coupled analysis tool, was used analysis. DLC1.2 1.6 were as cases, environmental condition...

This paper demonstrates the use of Kane’s method to derive equations motion for a spar-type floating offshore wind turbine taking into account flexibility members. The recently emerged reduces effort required complex multi-body systems, making them simpler model and more readily solved by computers. Further, installation procedure external vibration control devices on using is described, ease t...

A comprehensive investigation of the directional bending performance a 4-leg jacket substructure, supporting 3 MW offshore wind turbine, has been carried out in this study. The substructure with Pratt bracing system which is already installed southwest farm South Korea chosen as reference support structure. numerical model 3MW structure (i.e., tower, transition piece, and structure) configured,...

This paper introduces the development of a new software framework for research, design, and development of wind energy systems which is meant to 1) represent a full wind plant including all physical and nonphysical assets and associated costs up to the point of grid interconnection, 2) allow use of interchangeable models of varying fidelity for different aspects of the system, and 3) support sy...

This work presents the first results from a field test to proof the concept of LIDAR assisted collective pitch control using a scanning LIDAR device installed on the nacelle of a research turbine. The purpose of the campaign was to show that a reduction of rotor speed variation is feasible with a feedforward update without changing the feedback controller. Although only a small amount of data c...