EXPERIMENTS ON REDUCED SCALE FWT

EXPERIMENTS ON REDUCED SCALE FWT

In the previous chapters, high order sliding mode control with gain adaptation algorithms has been applied to floating wind turbine systems. Different control strategies, such as collective blade pitch control, individual blade pitch control and control combined with electric machine have been de- signed, all of those controllers being evaluated thanks to the co-simulations made by SIMULINK and FAST. Indeed, FAST provides a precise numerical model of FWT that makes it possible to get accurate numerical simulations with time-saving, low cost and easy for control implementation. The numerical based simulation is widely used in FWT researches (see General introduction). Neverthe- less, it is still necessary to make experiments in a controlled and repeatable environment before its using control solutions in practical applications (scale 1). Comparing with the traditional on-shore wind turbine, the design of an experimental set-up of floating one is much more complex due to the coupling between the hydrodynamics of the platform and the aerodynamics of the rotor. This coupling problem presents several challenges for FWT experimental set-up.The hybrid methodology (Carrion and Spencer Jr 2007) reproduces the behaviour of large-scale structure through numerical simulation and physical experiment simultaneously, and has been ap- plied to the FWT system in recent years (Hall and A. J. Goupee 2018; Hall, A. Goupee, and J. Jonkman 2018; Vittori et al. 2018; Arnal 2020). In this work, the experiments are carried out in a wave tank. Then, the hybrid model is composed by a scaled floating structure and a numerical rotor model (modeled by FAST software). The whole system can be defined as a combination of basin experimental set-up and software-in-the-loop (SIL). While the experimental system is scaled in the wave tank, and its dynamics captured by sensors, the numerical model in SIL simulation is used for the aerodynamic forces calculation in real-time. Then, the calculated aerodynamic forces are applied on the reduced scale system by an actuator

Experiments are made in the Ecole Centrale de Nantes (ECN) wave tank (see Figure 5.2). The wave tank experiments make it possible to test the response of the FWT hybrid system with different controllers under a repeatable environment. The physical system used in the experiments (Figure 5.2) is a 1/40 scale 10 MW spar floating wind turbine developed by (Arnal 2020) in the SOFTWIND project. This system is carried out for the purpose of developing innovative experimental test bench dedicated to the wave tank testing of floating wind turbines. The description of the experimental set-up is displayed in Figure 5.3. The tower consists of a flexible mast that is surrounded by an external casing. This casing is rigidly connected to the floater. Three mooring lines are connected between the floater and the bottom of the wave tank in order to limit the motions of the floater. At the top of the model is the RNA that is composed by the actuator and sensors, and the WIFI system that interacting with the real-time numerical model. As recalled in Footnote 1, the actuator allows to generate the aerodynamic forces calculated by the numerical simulations. The main properties of the experimental set-up, the target FWT and the estimatedThe description of the experimental set-up is displayed in Figure 5.3. The tower consists of a flexible mast that is surrounded by an external casing. This casing is rigidly connected to the floater. Three mooring lines are connected between the floater and the bottom of the wave tank in order to limit the motions of the floater. At the top of the model is the RNA that is composed by the actuator and sensors, and the WIFI system that interacting with the real-time numerical model. As recalled in Footnote 1, the actuator allows to generate the aerodynamic forces calculated by the numerical simulations. The main properties of the experimental set-up, the target FWT and the estimated