NREL Research Facilitates Several Multi-Party Collaborations in Advanced Controls
NREL’s two Advanced Controls Research Turbines (CARTs) are providing the basis for several collaborative research projects involving multiple partners to advance the state-of-the-art wind turbine controls.
Two research projects are being conducted on NREL’s two-bladed advanced research turbine (CART2). For one project, NREL is collaborating with lidar manufacturer Avent-Leosphere and controller manufacturer DNV-GL to improve turbine performance in above rated operating conditions using blade pitch control. Avent-Leosphere mounted their lidar on the nacelle of the CART2 that measures the wind field ahead of the turbine and provides commands to the pitch controller provided by the feed-forward pitch controller designed by DNV-GL. Initial results have shown significant improvement in speed regulation and reductions in turbine loads. This improvement in rotor-speed regulation also results in reduced tower bending loads in important frequency bands for reducing fatigue loads.
For the second CART2 project, NREL is collaborating with TU-Delft to test independent blade pitch controls. These controls reduce blade loads due to wind shear and turbulent eddies that impact the rotor disk. The controller is also targeted at the ability to smooth out the impact of upwind turbine wake effects inside a wind plant. This collaboration seeks to quantify the performance of more advanced independent blade pitch control algorithms employing advanced state-space control methods compared to industry standard classically designed controllers.
NREL’s three-bladed CART is also the focus of two collaborative research efforts. NREL has collaborated with lidar manufacturer ZephIR on a research project to test ZephIR’s continuous wave lidar that is mounted on the turbine’s nacelle. Field tests of feed-forward controllers using that lidar were concluded in June of this year. In November, NREL will collaborate with DTU-Wind Energy to field test controls using the DTU-Wind lidar, which measures windspeed ahead of the machine in much more detail than any lidar tested to date. This lidar should improve the performance of feed-forward pitch controllers.
In addition to the knowledge gained through its collaborative research efforts with industry partners, NREL is making a large deposit in its knowledge bank through collaborations with the University of Stuttgart and the University of Minnesota. Dr. David Schlipf, an internationally recognized expert in lidar-based controls from the University of Stuttgart, and professor Peter Seiler with the University of Minnesota, began one-year appointments to collaborate with NREL researchers in wind turbine and wind farm controls.