Coordinateurs du projet
Context
Marine renewable energy (MRE) systems incorporate advanced control functions to optimize energy conversion efficiency. In the case of a floating wind turbine, the orientation of the nacelle, the torque on the rotor shaft, and the orientation of the blades are continuously updated. The setpoint values are calculated according to a control law that takes into account the speed and direction of the incident wind and the movements of the platform. For wave energy converters, energy extraction can be optimized by adjusting the resistance torque on the generator shaft in real time, generally based on the incident swell and the movements of the system.
The Centrale Nantes tanks allow controlled conditions of swell, wind, and current to be reproduced in the laboratory. These testing facilities are often used to model MRE systems under production, survival, or installation conditions. One of the main difficulties in the experimental modeling of an MRE system is to represent and control, on a reduced scale, the damping due to energy conversion.
The experimental modeling team at the LHEEA laboratory proposes to equip its models with an embedded controller capable of controlling actuators in real time and recording measurements from sensors. The controller acquires signals, calculates setpoints according to a control strategy, and drives the actuators. Its real-time operating system ensures that these tasks are always performed within the same time interval.
Scientific breakthroughs and innovation
As part of its research work, the experimental hydrodynamics team at the LHEEA laboratory at Centrale Nantes has already implemented complex control systems on wave energy converters. Real-time calculations associated with control laws were performed on a computer at the edge of the basin, requiring cables for data and power transfer. In the case of a floating system, the presence of these cables introduces unwanted external forces on the models, which are often not quantified. The controller proposed here can be integrated into a watertight box and mounted on the models. It will be controlled via a Wi-Fi link from a supervisory PC at the edge of the basin, limiting the number of cables between the model and the bridge that could influence the movements of the float.
Expected technical and economic impact
This project enables Centrale Nantes’ testing platform to offer developers an innovative tool for validating control laws during basin tests. This new tool complements the range of diagnostic tools already associated with testing facilities and opens up new service opportunities.
Centrale Nantes can now develop more comprehensive, higher-performance MRE system models that will integrate control-command strategy and a measurement acquisition system. The device will be used in particular as part of the WEAMEC SOFTWIND project.
Results
The CrioEMR project, funded by Weamec, has enabled the Lheea laboratory at Centrale Nantes to equip itself with an onboard controller to measure and control servo systems on models tested in tanks. This equipment was used in particular for the development of Softwind, a new testing method for representing aerodynamic forces on floating wind turbine models and for testing their control laws. This system, developed in 2019, was qualified and validated during the Softwind SPAR campaign in early 2020. Since then, it has been used for Blue Growth Farm tests, a multifunctional platform combining aquaculture, floating wind power, and wave energy systems, as well as for Helofow tests, a floating wind turbine SPAR float including internal force measurement. It enables the laboratory to expand its testing capabilities and position itself for new research projects by offering innovative testing techniques.