Frequency domain modelling of wind turbine structures
- Risoe National Laboratory, Roskilde (Denmark). Test Station for Wind Turbines
The present paper describes a frequency domain model of the structure of an operating horizontal axis wind turbine. The frequency domain model is implemented along with an analogous time domain modeling the Risoe PC code Design Basis 2, and a more detailed description of the model is offered in a Risoe report by Soerensen (1994). The structure of an operating wind turbine is affected by essential non-linearities between structural variables on blades and tower respectively. These non-linearities are caused by the rotation of the blades. The transformations between the blade coordinate systems and the tower coordinate system will depend on the instantaneous azimuth positions of the blades as they rotate. Frequency domain analysis are much faster than time simulations and in some respects they give more insight into the dynamics of the structure. However, the non-linear terms in the dynamic equations for a complex wind turbine structure are usually thought to preclude the use of frequency domain methods. Design Basis 2 is used to verify the frequency domain model comparing loads on the structure calculated with the frequency domain model both to loads calculated with the time domain model and to measured loads. Examples show that frequency and time domain calculations of typical PSD`s of loads are in very good agreement. Also the agreement between the calculated and measured PSD`s is good. Moreover, Design Basis 2 has shown that the frequency domain model results in an extremely fast calculation method.
- OSTI ID:
- 93016
- Report Number(s):
- CONF-950116-; ISBN 0-7918-1294-4; TRN: IM9537%%59
- Resource Relation:
- Conference: 1995 American Society of Mechanical Engineers (ASME) energy sources technology conference and exhibition, Houston, TX (United States), 29 Jan - 1 Feb 1995; Other Information: PBD: 1995; Related Information: Is Part Of Wind energy 1995. SED-Volume 16; Musial, W.D.; Hock, S.M. [eds.] [National Renewable Energy Lab, Golden, CO (United States)]; Berg, D.E. [ed.] [Sandia National Labs., Albuquerque, NM (United States)]; PB: 298 p.
- Country of Publication:
- United States
- Language:
- English
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