Aalborg Universitet Wind Energy Systems and Technologies

Aalborg Universitet

Wind Energy Systems and Technologies, Aalborg University

Frigaard, Peter

Publication date:2007

Document VersionPublisher's PDF, also known as Version of record

Link to publication from Aalborg University

Citation for published version (APA):Frigaard, P. (2007). Wind Energy Systems and Technologies, Aalborg University. Department of CivilEngineering, Aalborg University.

General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.

? Users may download and print one copy of any publication from the public portal for the purpose of private study or research. ? You may not further distribute the material or use it for any profit-making activity or commercial gain ? You may freely distribute the URL identifying the publication in the public portal ?

Take down policyIf you believe that this document breaches copyright please contact us at [email protected] providing details, and we will remove access tothe work immediately and investigate your claim.

Downloaded from vbn.aau.dk on: November 25, 2021

https://vbn.aau.dk/en/publications/b96e92c0-c9b4-11dc-8dd8-000ea68e967b

Faculty of Engineering, Science and Medicine - Aalborg University

Wind Energy Systems and TechnologiesAalborg UniversityResearch areas:• Energy planning• Power electronics and power systems• Control• Blade design – composite materials• Aerodynamics and aeroelasticity• Structural dynamics• Foundation• Load and safety

Master and PhD programs in wind energy

Offshore wind turbine at Aalborg Østhavn


Department of Energy TechnologyResearch Focus in Wind Turbine Systems:

Rotor Gearbox GeneratorPower

electronics Transformer Grid

MechanicalEnergy

ElectricalEnergy

Grid Requirements!

Control System

Wind Energy


Research ProjectsExamples of Project :

• Stability and control of Wind farms in Power Systems• Integration and Control of Wind Farms

in the Danish Electricity System• Offshore Wind Power Grid Connection and Reliability• Operation and control of distribution systems with high

level integration of renewable generation units• Modeling and Control of Grid Converter• Simulation Platform for Wind Turbines• Monitoring and Advanced Control of Three Phase DPGS

Project• Advanced Power Converter for UNIversal and FLEXible

Power Management in Future Electricity Network (EU)


Simulation Platform

Home Page for Simulation Platform Project:http://www.iet.aau.dk/Research/spp.htm


Department of Electronic Systems- Section for Automation & Control

Current wind energy activities:• Industrial study group in model based control of wind

turbines• Research in connection with MSc projects• Industrial PhD project regarding robust control of wind

turbines• Industrial PhD project regarding model predictive

control of wind turbines


Department of Mechanical Engineering

Wind energy activities:

• Almost exclusively devoted to characterisation, modelling/analysis, design and optimization of advanced composite materials and sandwich structures for wind turbine blades

• Several ongoing and recent projects with partners in wind energy sector (wind turbine blade manufacturers, material suppliers, research institutions)


Examples of research projects“Structural Instability Phenomena in Wind Turbine Blades”

Objectives:• Characterisation and modelling of

buckling phenomena in windturbine blades:


“Buckling of wind turbine rotor blades: Analysis, design and experimental validation”Industrial Ph.D. project with Vestas Wind Systems A/S - 2002-2007

Objectives:• Development of analysis tools for

the prediction of local buckling.• Analytical (closed-form) and

numerical methods.• Verification/validation of analysis

results through comparison withexperimenatal data obtained form model tests as well as full scaletests.

• Structural design optimization ofwing/blade.


9 m test section – 4 pt. bending


Department of Civil Engineering

Wind energy activities:

• Loads and safety – risk analysis• Foundation – geotechnics• Wave and current loads - scour


Load & Safety – Risk analysisProbabilistic design of wind turbines:• Reliability & risk analysis of components using probabilistic

methods:– Blades + hub + tower + foundation – Gearboxes, generators, …

• Reliability updating using measurements / condition monitoring• Probabilistic adjustment of safety factors

using test results etc.


Key aspects:• Reliability - Availability• Maintenance costs• Energy production (benefits)

Offshore:• Weather windows• Availability of transport and equipment

Load & Safety – Risk analysis

Probabilistic approach

Probabilistic approach

Risk-based operation & maintenance of offshore wind turbines:

Optimal decisions: Minimum total expected costs in lifetime

Experience from RBI for offshore oil & gas structures


Foundation and Geotechnics

• Soil - Structure interaction of foundations for offshore wind turbines

• Wind-turbine footings on layered ground• Verification by tests

– Laboratory model test– Field trials at reduced scale– Full-scale tests and measurements


gravity based foundation - bucket foundation - monopile foundation - tripod foundation

Foundation and GeotechnicsSoil - Structure interaction of foundations for offshore wind turbines:


Wind-turbine footings on layered ground:



Laboratory tests:



Test site for offshore wind turbine research in Frederikshavn:



Test site for offshore wind turbine research in Frederikshavn:



Characterization of the environmental loads related to the offshore position:

•Waves; irregular breaking

•Currents; wave generated / tidal

In order to evaluate the structure

Wave and current loads - Scour

•Loads from wave/current

•Loads from ice

•Erosion holes (Scour)

•Scour protection


Wave Run-up Height (level) of SpraySlamming forces on Boat LandingsTotal Wave Forces on Shaft

Laboratory tests:

Wave and current loads - scour


Area:1.5 m x 0.93 m

Step:1.5 cm

Time:35 min

Measurements of Scour hole in laboratory test (Pile removed)


Comparative tests with Scour Protection:

Wave and current loads - scour


ContactsEnergy: www.iet.aau.dk/

Assoc. Professor John K. Pedersen: [email protected]

Control: www.control.aau.dkProfessor Jakob Stoustrup: [email protected]

Mechanical: www.ime.auc.dkProfessor Ole Thybo Thomsen: [email protected]

Civil Engineering:Professor John Dalsgaard Sørensen [email protected]

Documents

Aalborg Universitet Wind Energy Systems and Technologies