This document reports on reduction of wind turbine fatigue loads on multi-MW wind turbines with passive adaptive strategies or by reducing rotor weight.Passive adaptive structural load alleviation is achieved by combining well-tuned speed controllers, with load alleviation capabilities, and new adaptive blade congurations developed by project partners at the University of Bristol. New types of composite material, whose properties vary spatially both along and across the blade, are used to produce two adaptive, aero-elastically tailored blade congurations named material adaptive and combined adaptive. Material bend-twist coupling is induced by anisotropic composite materials, whereas combined coupling is induced by embedding anisotropy and using a curved, swept blade planform to produce additional geometric bend-twist coupling. The two aero-elastic blade configurations are used in the NREL 5 MW wind turbine rotor and compared against the NREL 5 MW baseline rotor.Drive-train viscous losses are added to the electrical loses to make all three wind turbines as similar as possible and allow a fair performance comparison. Controllers are designed in frequency domain and their structure and parameters are also kept similar when possible for the three the wind turbines. Power production simulations are carried out to assess fatigue loading over the operating wind speed range (4 m/s to 24 m/s). An extreme gust simulation scenario is also tested.A control system is also designed for the light weight rotor DTU 10 MW wind turbine. The DTU 10 MW wind turbine was designed at the Technical University of Denmark (DTU) in their HAWC 5 software tool and converted into a Bladed model by project partners at the University of Bristol. The DTU 10 MW turbine has a light weight rotor developed by increasing the thickness to chord ratio of airfoils along the blade span and adjusting the thickness of the load carrying structural elements in the blade such that the blade twist passively adapts to changes in the wind field, and weight and edgewise loads scale better with flapwise loads while considering the negative impact from higher thickness ratio on power and thrust. Fatigue loads are also assessed for this wind turbine exemplar.
|Publisher||University of Strathclyde|
|Number of pages||37|
|Publication status||Published - 24 Jan 2020|
- power capture
- wind turbines
- wind power