Print Email Facebook Twitter Wind tunnel tests with combined pitch and free-floating flap control: data-driven iterative feedforward controller tuning Title Wind tunnel tests with combined pitch and free-floating flap control: data-driven iterative feedforward controller tuning Author Navalkar, S.T. (TU Delft Team Raf Van de Plas) Bernhammer, L.O. (TU Delft Wind Energy) Sodja, J. (TU Delft Aerospace Structures & Computational Mechanics) van Solingen, E. van Kuik, G.A.M. (TU Delft Wind Energy) van Wingerden, J.W. (TU Delft Team Raf Van de Plas) Date 2016 Abstract Wind turbine load alleviation has traditionally been addressed in the literature using either full-span pitch control, which has limited bandwidth, or trailing-edge flap control, which typically shows low control authority due to actuation constraints. This paper combines both methods and demonstrates the feasibility and advantages of such a combined control strategy on a scaled prototype in a series of wind tunnel tests. The pitchable blades of the test turbine are instrumented with free-floating flaps close to the tip, designed such that they aerodynamically magnify the low stroke of high-bandwidth actuators. The additional degree of freedom leads to aeroelastic coupling with the blade flexible modes. The inertia of the flaps was tuned such that instability occurs just beyond the operational envelope of the wind turbine; the system can however be stabilised using collocated closed-loop control. A feedforward controller is shown to be capable of significant reduction of the deterministic loads of the turbine. Iterative feedforward tuning, in combination with a stabilising feedback controller, is used to optimise the controller online in an automated manner, to maximise load reduction. Since the system is non-linear, the controller gains vary with wind speed; this paper also shows that iterative feedforward tuning is capable of generating the optimal gain schedule online. To reference this document use: http://resolver.tudelft.nl/uuid:f6a7b84f-4f90-428c-94ff-68d0601f53ea DOI https://doi.org/10.5194/wes-1-205-2016 Source Wind Energy Science, 1 (2), 205-220 Part of collection Institutional Repository Document type journal article Rights © 2016 S.T. Navalkar, L.O. Bernhammer, J. Sodja, E. van Solingen, G.A.M. van Kuik, J.W. van Wingerden Files PDF Wind_tunnel_tests_with_co ... ontrol.pdf 6.11 MB Close viewer /islandora/object/uuid:f6a7b84f-4f90-428c-94ff-68d0601f53ea/datastream/OBJ/view