| 1. |
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| 2. |
- Kjellin, Jon, et al.
(författare)
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Electrical Starter System for an H-Rotor Type VAWT with PM-Generator and Auxiliary Winding
- 2011
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Ingår i: Wind Engineering. - : Multi Science Publishing. - 0309-524X .- 2048-402X. ; 35:1, s. 85-92
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Tidskriftsartikel (refereegranskat)abstract
- In order to operate a modern wind turbine an effective start procedure is required. This article presents an electrical start for a VAWT which is shown to have advantages over an aerodynamic start. An electrical starter for a 12 kW VAWT has been designed and built. The starter is based on a six-step modulated inverter that is feedback-controlled by the rotor position. The inverter is connected to an auxiliary winding in the generator to separate the starter electronics from the main system. The system has been simulated and experimentally verified in the wind turbine setup.
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| 3. |
- Möllerström, Erik, et al.
(författare)
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Eigen Frequencies of A Vertical Axis Wind Turbine Tower Made of Laminated Wood and the Effect Upon Attaching Guy Wires
- 2014
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Ingår i: Wind Engineering. - Brentwood, United Kingdom : Multi-Science Publishing. - 0309-524X .- 2048-402X. ; 38:3, s. 277-290
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Tidskriftsartikel (refereegranskat)abstract
- Eigen frequencies of a vertical axis wind turbine tower made out of laminated wood which are both bolted to the ground and supported by guy wires are studied and compared. Using beam theory, an analytical model taking the guy wires into account for calculating the first mode eigen frequency of the tower has been derived. The analytical model is then evaluated by comparing with FEM-simulations and measurements performed on the actual tower. The model is found to be reasonably accurate keeping in mind that the estimated masses and second moments of area are somewhat rough. Furthermore the model can be used to give an indication of the magnitude of change in eigen frequency when modifying a tower or guy wire property.
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| 4. |
- Ottermo, Fredric, 1975-, et al.
(författare)
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Resonances and Aerodynamic Damping of a Vertical Axis Wind Turbine
- 2012
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Ingår i: Wind Engineering. - Essex, UK : Multi-Science Publishing. - 0309-524X .- 2048-402X. ; 3:36, s. 297-304
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Tidskriftsartikel (refereegranskat)abstract
- The dynamics of a straight-bladed vertical axis wind turbine is investigated with respect to oscillations due to the elasticity of struts and shaft connecting to the hub. In particular, for the three-bladed turbine, a concept is proposed for dimensioning the turbine to maximize the size of the resonance free rpm range for operation. The effect of aerodynamic damping on the struts is also considered. The damping of these types of oscillations for a typical turbine is found to be good.
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| 5. |
- Asadi, Saeed, 1987, et al.
(författare)
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Multibody dynamic modelling of a direct wind turbine drive train
- 2020
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Ingår i: Wind Engineering. - 0309-524X .- 2048-402X. ; 44:5, s. 519-547
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Tidskriftsartikel (refereegranskat)abstract
- Wind turbines normally have a long operational lifetime and experience a wide range of operating conditions. A representative set of these conditions is considered as part of a design process, as codified in standards. However, operational experience shows that failures occur more frequently than expected, the costlier of these including failures in the main bearings and gearbox. As modern turbines are equipped with sophisticated online systems, an important task is to evaluate the drive train dynamics from online measurement data. In particular, internal forces leading to fatigue can only be determined indirectly from other locations’ sensors. In this contribution, a direct wind turbine drive train is modelled using the floating frame of reference formulation for a flexible multibody dynamics system. The purpose is to evaluate drive train response based on blade root forces and bedplate motions. The dynamic response is evaluated in terms of main shaft deformation and main bearing forces under different wind conditions. The model was found to correspond well to a commercial wind turbine system simulation software (ViDyn)
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| 6. |
- Gantasala, Sudhakar, et al.
(författare)
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Identification of ice mass accumulated on wind turbine blades using its natural frequencies
- 2018
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Ingår i: Wind Engineering. - : Sage Publications. - 0309-524X .- 2048-402X. ; 42:1, s. 66-84
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Tidskriftsartikel (refereegranskat)abstract
- This work demonstrates a technique to identify information about the ice mass accumulation on wind turbine blades using its natural frequencies, and these frequencies reduce differently depending on the spatial distribution of ice mass along the blade length. An explicit relation to the natural frequencies of a 1-kW wind turbine blade is defined in terms of the location and quantity of ice mass using experimental modal analyses. An artificial neural network model is trained with a data set (natural frequencies and ice masses) generated using that explicit relation. After training, this artificial neural network model is given an input of natural frequencies of the iced blade (identified from experimental modal analysis) corresponding to 18 test cases, and it identified ice masses’ location and quantity with a weighted average percentage error value of 17.53%. The proposed technique is also demonstrated on the NREL 5-MW wind turbine blade data.
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| 7. |
- Gipe, Paul, et al.
(författare)
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An overview of the history of wind turbine development : Part I — The early wind turbines until the 1960s
- 2022
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Ingår i: Wind Engineering. - London : Sage Publications. - 0309-524X .- 2048-402X. ; 46:6, s. 1973-2004
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Tidskriftsartikel (refereegranskat)abstract
- We review the development of wind turbines for generating electricity from the late 19th century to the present, summarizing some key characteristics. We trace the move from two to four blade wind turbines to the three blades common today. We establish that it was not the governmental-funded wind programs with its large-scale prototypes of the 1970–80s that developed into the commercial turbines of today. Instead it was the small-scale Danish wind turbines, developed for an agricultural market, that developed into the commercial turbines of today. And we show that much of what we know today about wind turbine design was known by the 1930s and certainly well known by the late 1950s. This work is divided into two parts: the first part takes up the development from the first electricity producing wind turbines through to the 1960s and a second part on development from the 1970s onward. © The Author(s) 2022.
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| 8. |
- Gipe, Paul, et al.
(författare)
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An overview of the history of wind turbine development : Part II–The 1970s onward
- 2023
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Ingår i: Wind Engineering. - London : Sage Publications. - 0309-524X .- 2048-402X. ; 47:1, s. 220-248
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Tidskriftsartikel (refereegranskat)abstract
- We review the development of wind turbines for generating electricity from the late 19th century to the present, summarizing some key characteristics. We trace the move from two and four blade wind turbines to the three blades common today. We establish that it was not the governmental-funded wind programs with its large-scale prototypes of the 1970–80s that developed into the commercial turbines of today. Instead, it was the small-scale Danish wind turbines, developed for an agricultural market, that developed into the commercial turbines of today. And we show that much of what we know today about wind turbine design was known by the 1930s and certainly well known by the late 1950s. This work is divided into two parts: the first part takes up the development from the first electricity producing wind turbines through to the 1960s and a second part on development from the 1970s onward. © The Author(s) 2022.
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| 9. |
- Möllerström, Erik, 1984-, et al.
(författare)
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Calculational model for first-mode eigenfrequency of a semi-guy-wired vertical-axis wind turbine tower
- 2021
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Ingår i: Wind Engineering. - London : Sage Publications. - 0309-524X .- 2048-402X. ; 45:2, s. 205-212
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Tidskriftsartikel (refereegranskat)abstract
- A simple model for accounting for tower mass when estimating the first-mode eigenfrequency of a semi-guy-wired tower has been derived. This extends previous work where an analytical model of the semi-guy-wired tower of a 200-kW vertical-axis wind turbine was developed. The model was primarily used to estimate the eigenfrequencies as a result of adding guy wires to a free-standing tower (thus creating a semi-guy-wired setup). However, a weakness with the model was that the tower mass was accounted for in a rough way that essentially ignored the guy wires, which gave a larger-than-necessary error. In this work, an effective top mass, that takes into account the tower mass and the constraints from the guy wires, is derived to achieve a higher accuracy when estimating the first-mode eigenfrequency. This, together with the earlier models, gives a more complete method to estimate the eigenfrequencies for a semi-guy-wired wind turbine. © The Author(s) 2019.
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| 10. |
- Perdana, Abram, 1974, et al.
(författare)
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Factors Influencing Design of Dynamic Reactive Power Compensation for an Offshore Wind Farm
- 2009
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Ingår i: Wind Engineering. - 0309-524X .- 2048-402X. ; 33:3, s. 273-286
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates factors that influence the design of dynamic reactive power compensation (DRPC) for an offshore wind farm consisting of fixed-speed wind turbines.Several influencing factors are considered including DRPC device types and locations, network strength, and fault ride-through (FRT) capability of individual wind turbines in the wind farm. The DRPC alternatives discussed in this paper comprise of a STATCOM and an SVC. It is found that the exclusion of wind turbine FRT capability results in too large DRPC size estimation. In the case of wind turbines equipped with FRT capability, it was found that the investment cost for both STATCOM and SVC options are comparable. The study also emphasizes the necessity of performing dynamic analysis to correctly design the size andlocation of the DRPC device.
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