Research Projects

Objective of this project is to increase the life-time of power electronics used in wind turbines and improve on early damage detection of power electronics components. This way a predictive maintenance schedule similar to that realized for gear boxes can be realized.
Initially, a fast measurement system has been developed to take input and output signals of power electronics within a micro second time scale in order to identify failure causes. Next, the measurement system has been extended to a rather manufacturer-independent monitoring system for use in existing wind turbines (retro fitting) without any new certification.
Based on the insights accomplished during this phase of the project, a prototype of a compensation converter has been built (Figure) that besides realizing an integrated monitoring system for power electronic also provides modern ancillary services for older wind turbines.

Term 2014…2018

Off-shore wind turbines operate under harsh conditions and despite these critical technical requirements for strength and stability, the materials must be cost-efficient and recyclable. The key innovation in WALiD is the introduction of thermoplastic composite materials and processing into wind blade applications.

An 11 strong European consortium has secured 3,964,797 euros of EU funding for development of cost effective materials for larger blades for off-shore wind energy applications.  This project has received funding from the European Uniion’s Seventh Framework Programme for research, technological development and demonstration..

Utilized variants of offshore support structures are as follows: gravitaional foundation, monopile, tripile, tripod, jacket. A variable parameter model is derived for each type of support structure. Hence, it is possible to reduce the model to the relevant degrees of freedom (e.g. acceleration of load calculations) as well as adjustment to external conditions.

The interaction between soil and support structure is included in the code. For gravitational foundations the foundation theory for heavy machines is implemented that has been succesfully utilized for offshore foundations. In case of tripile/tripod the soil paramters are translated into stiffness parameters. For jackets an automised strategy is used to find the proper relacement as a monopile. The nonlinear soil inteaction has been succesfully transformed into so called p-y curves for monopiles. In addition, the complete interaction between offshore structure and tower is considered to find a load effective design for the complete structure.

This project has been funded by “Ministerium für Wirtschaft, Arbeit und Tourismus Mecklenburg-Vorpommern”.

Wind Energy Converters (WEC) are among those technical structures with highest number (>10⁹) and at the same time high level of load cycles. Due to increasing power performance, in particular during recent years, wind energy converters (WEC) are reaching design data, in which mechanical stress within system components are no longer compatible with conventional stationary industrial plants.

Observer structures are used to extract state information on the wind turbine usually not or only difficult to access, in any case, without installation of additional costly measuring devices.

The torsional moment of the drive train is particulary important. Depending on details of the observer model, it could be utilized to analyze loads in the different stages of the drive train. The same information could also be used  by feeding the observer signal into the generator torque demand to realize active drive train damping.

Proper software has been developed and a prototype of this observer has been implemented into the inverter controller of a turbine model. It has been tested in a small scale test stand of the ILAB at the Bremen University and also in an aeroelastic numerical simulation environment sufficient for load analysis of a generic 2 MW wind energy converter with a Kaimal wind field of different turbulence classes.