Design limits and solutions for very large wind turbines

4. UpWind: Research activities .................................................................................................... 56
4.1 Work Package 2: Aerodynamics and aeroelastics ..............................................................................58
Challenges and main innovations ........................................................................................................ 58
Research activities and results ........................................................................................................... 59
Structural dynamics — large defl ections and non-linear effects .......................................................... 59
Advanced aerodynamic models ........................................................................................................ 59
Aerodynamic and aeroelastic modelling of advanced control features and aerodynamic devices ............ 60
Aeroelastic stability and total damping prediction including hydroelastic interaction ............................. 60
Computation of aerodynamic noise .................................................................................................. 60
4.2 Work Package 3: Rotor structures and materials ............................................................................... 61
Challenges and main innovations ........................................................................................................ 61
Results ............................................................................................................................................. 62
Task 1: Applied (phenomenological) material model ........................................................................... 62
Task 3.2 Micro-mechanics-based material model ............................................................................... 63
Task 3.3: Damage-tolerant design concept ........................................................................................ 64
Task 3.4: Upscaling — cost factors .................................................................................................. 66
4.3 Work Package 4: Foundations and support structures........................................................................ 67
Challenges and main innovations ........................................................................................................ 67
Results ............................................................................................................................................. 69
Task 1: Integration of support structure and wind turbine design ........................................................ 69
Task 2: Support structure concepts for deep-water sites .................................................................... 70
Task 3: Enhancement of design methods and standards .................................................................... 71
References ........................................................................................................................................ 72
4.4 Work Package 5: Control systems ..................................................................................................... 74
Challenges and main innovations ........................................................................................................ 74
Results ............................................................................................................................................. 75
Supervisory control implications of advanced control ......................................................................... 75
Online estimation of mechanical load for wind turbines ...................................................................... 76
Dual pitch control for out-of-plane-blade load reduction ...................................................................... 77
Identifi cation of wind turbines operating in closed loop ...................................................................... 78
LIDAR-assisted collective pitch control .............................................................................................. 79
Validation of load reducing controllers in full-scale fi eld tests ............................................................. 80
Hardware-in-the-loop testing of pitch actuators .................................................................................. 81
Riding through grid faults ................................................................................................................. 82
Impact of the drive train on wind farm VAR Control ............................................................................ 82
References ........................................................................................................................................ 83
Design limits and solutions for very large wind turbines
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