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  • 1.
    Aihara, Aya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Uzunoglu, Bahri
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Wind Flow Resource Analysis Of Urban Structures: A Validation Study2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In order to have better insight into the physics of the urban wind turbines, a Computational Fluid Dynamics (CFD) flow solver has been developed for industrial applications by Uppsala University and SOLUTE Ingenieros. Urban wind resource assessment for small scale wind applications present several challenges and complexities for that are different from large-scale wind power generation. Urban boundary layer relevant in this regime of flows have different horizontal profiles impacted by the buildings, low speed wind regimes, separation and different turbulence characteristics. Preliminary measurement results will be presented for a particular site in Huesca Spain where a measurement campaign is undertaken to validate the CFD results.

    Fulltekst (pdf)
    fulltext
  • 2.
    Dyachuk, Eduard
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Numerical Validation of a Vortex Model Against Experimental Data on a Straight-Bladed Vertical Axis Wind Turbine2015Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, nr 10, s. 11800-11820Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cyclic blade motion during operation of vertical axis wind turbines (VAWTs) imposes challenges on the simulations models of the aerodynamics of VAWTs. A two-dimensional vortex model is validated against the new experimental data on a 12-kW straight-bladed VAWT, which is operated at an open site. The results on the normal force on one blade are analyzed. The model is assessed against the measured data in the wide range of tip speed ratios: from 1.8 to 4.6. The predicted results within one revolution have a similar shape and magnitude as the measured data, though the model does not reproduce every detail of the experimental data. The present model can be used when dimensioning the turbine for maximum loads.

    Fulltekst (pdf)
    fulltext
  • 3.
    Dyachuk, Eduard
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Simulating Dynamic Stall Effects for Vertical Axis Wind Turbines Applying a Double Multiple Streamtube Model2015Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, nr 2, s. 1353-1372Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The complex unsteady aerodynamics of vertical axis wind turbines (VAWT) poses significant challenges to the simulation tools. Dynamic stall is one of the phenomena associated with the unsteady conditions for VAWTs, and it is in the focus of the study. Two dynamic stall models are compared: the widely-used Gormont model and a Leishman-Beddoes-type model. The models are included in a double multiple streamtube model. The effects of flow curvature and flow expansion are also considered. The model results are assessed against the measured data on a Darrieus turbine with curved blades. To study the dynamic stall effects, the comparison of force coefficients between the simulations and experiments is done at low tip speed ratios. Simulations show that the Leishman-Beddoes model outperforms the Gormont model for all tested conditions.

    Fulltekst (pdf)
    fulltext
  • 4.
    Dyachuk, Eduard
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Berhnoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Simulating Pitching Blade With Free Vortex Model Coupled With Dynamic Stall Model For Conditions Of Straight Bladed Vertical Axis Turbines2014Inngår i: 33Rd International Conference On Ocean, Offshore And Arctic Engineering, 2014, Vol 9A: Ocean Renewable Energy, AMER SOC MECHANICAL ENGINEERS , 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This study is on the straight bladed vertical axis turbines, which can be utilized for both wind and marine current energy. Vertical axis turbines have the potential of lower installation and maintenance cost. However complex unsteady fluid mechanics of these turbines imposes significant challenges to the simulation tools. Dynamic stall is one of the phenomena associated with the unsteady conditions, and it is in the focus of the study. The dynamic stall effects are very important for vertical axis turbines, since they are usually passively controlled through the dynamic stall. A free vortex model is used to calculated unsteady attached flow, while the separatedflow is handled by the dynamic stall model. This is compared to the model based solely on the Leishman-Beddoes algorithm. The results are assessed against the measured data on pitching airfoils. A comparison of force coefficients between the simulations and experiments is done at the conditions similar to the conditions of H-rotor type vertical axis turbines.

  • 5.
    Dyachuk, Eduard
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Dynamic Stall Modeling for the Conditions of Vertical Axis Wind Turbines2014Inngår i: AIAA Journal, ISSN 0001-1452, E-ISSN 1533-385X, Vol. 52, nr 1, s. 72-81Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Unsteady aerodynamics imposes additional demands on the modeling of vertical axis wind turbines. Large variations in the angles of attack of the blades cause force oscillations, which can lead to the fatigue-associated problems. Therefore, an accurate estimation of the dynamic loads is essential for the vertical axis wind turbines design. Dynamic stall modeling is in focus because it represents complex phenomena associated with the unsteady flow conditions. The purpose of the study is to find a suitable dynamic stall model for the vertical axis wind turbine conditions. Three versions of the Leishman-Beddoes model are explicitly presented. Additional modifications are implemented for the model to work when the angles of attack change sign and have high amplitudes. All the model parameters are presented. The model is assessed against measured data. The conditions for the simulation tests are close to the vertical axis wind turbine operational conditions. Aversion of the model, originally designed for low Mach numbers, is the most accurate throughout a number of tests.

  • 6.
    Dyachuk, Eduard
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Simulating Pitching Blade With Free Vortex Model Coupled With Dynamic Stall Model for Conditions of Straight Bladed Vertical Axis Turbines2015Inngår i: Journal of solar energy engineering, ISSN 0199-6231, E-ISSN 1528-8986, Vol. 137, nr 4, artikkel-id 041008Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study is on the straight bladed vertical axis turbines (VATs), which can be utilized for both wind and marine current energy. VATs have the potential of lower installation and maintenance cost. However, complex unsteady fluid mechanics of these turbines imposes significant challenges to the simulation tools. Dynamic stall is one of the phenomena associated with the unsteady conditions, and it is in the focus of the study. The dynamic stall effects are very important for VATs, since they are usually passively controlled through the dynamic stall. A free vortex model is used to calculated unsteady attached flow, while the separated flow is handled by the dynamic stall model. This is compared to the model based solely on the Leishman-Beddoes algorithm. The results are assessed against the measured data on pitching airfoils. A comparison of force coefficients between the simulations and experiments is done at the conditions similar to the conditions of H-rotor type VATs.

  • 7.
    Dyachuk, Eduard
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lalander, Emilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Influence of incoming flow direction on spacing between vertical axis marine current turbines placed in a row2012Inngår i: Proceedings of the ASME 31th International Conference on Ocean, Offshore and Artic Engineering, vol. 7, 2012, s. 285-291Konferansepaper (Fagfellevurdert)
    Abstract [en]

    From the commercial point of view it may be beneficial to installa set of marine current turbines forming a park, by analogy with windparks. Consequently, this motivates research on park configurations.An array of ten vertical axis marine current turbines is simulatedto study how the distance between the turbines affects the performanceof the park for different flow directions. The simulations are performedusing a two-dimensional vortex method. An array of identical turbinesis created, where all turbines are on a single line. The turbinesare operated at the tip speed ratio, which corresponds to the highestpower coefficient for a single turbine. The distance between the turbinesis varied and the total power from the array is compared to the turbinespacing for different flow directions.Additionally, flow data from a real site is used to find an optimalorientation of the line of turbines. The performance of the arrayis estimated for the site as a function of turbine spacing.

  • 8.
    Dyachuk, Eduard
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Rossander, Morgan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Measurements of the Aerodynamic Normal Forces on a 12-kW Straight-Bladed Vertical Axis Wind Turbine2015Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, nr 8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The knowledge of unsteady forces is necessary when designing vertical axis wind turbines (VAWTs). Measurement data for turbines operating at an open site are still very limited. The data obtained from wind tunnels or towing tanks can be used, but have limited applicability when designing large-scale VAWTs. This study presents experimental data on the normal forces of a 12-kW straight-bladed VAWT operated at an open site north of Uppsala, Sweden. The normal forces are measured with four single-axis load cells. The data are obtained for a wide range of tip speed ratios: from 1.7 to 4.6. The behavior of the normal forces is analyzed. The presented data can be used in validations of aerodynamic models and the mechanical design for VAWTs.

    Fulltekst (pdf)
    fulltext
  • 9.
    Forslund, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Thomas, Karin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Validation of a Coupled Electrical and Hydrodynamic Simulation Model For A Vertical Axis Marine Current Energy Converter2018Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 11, nr 11, artikkel-id 3067Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper validates a simulation model that couples an electrical model in Simulink with a hydrodynamic vortex-model by comparing with experimental data. The simulated system is a vertical axis current turbine connected to a permanent magnet synchronous generator in a direct drive configuration. Experiments of load and no load operation were conducted to calibrate the losses of the turbine, generator and electrical system. The power capture curve of the turbine has been simulated as well as the behaviour of a step response for a change in tip speed ratio. The simulated results agree well with experimental data except at low rotational speed where the accuracy of the calibration of the drag losses is reduced.

    Fulltekst (pdf)
    fulltext
  • 10.
    Forslund, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Mendoza, Victor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Impact of Blade Pitch Angle on Turbine Performance of a Vertical Axis Current TurbineManuskript (preprint) (Annet vitenskapelig)
  • 11.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Fluid mechanical simulations and development for vertical axis turbines2011Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The aerodynamics of vertical axis turbines is typically studied using streamtube, vortex or CFD models. This thesis focuses on the first two models, which are the computationally faster ones. The streamtube model is the fastest, allowing three-dimensional modeling of the turbine, but lacks a proper description of the flow through the turbine and does not include any time dependence in the solution. The vortex model used is two-dimensional, but gives a description of the flow around the turbine and can handle time dependence. Effects of a velocity profile and the inclusion of struts have been investigated using the streamtube model. Simulations with the velocity profile indicate that the vertical axis turbine should be quite insensitive to the profile (with respect to the power coefficient). If the applied profile is perpendicular to the rotational axis, the turbine generally performs better if the blade moves against the flow at the high velocity side of the profile. When including struts, the structural mechanics was included and the calculations shows that if turbines are designed for high flow velocities, additional struts are required, reducing the efficiency for lower flow velocities. Turbines in channels and turbine arrays were studied with the vortex model. The channel study included both the numerical parts of the simulations and the effects of channel width were investigated. On the numerical side, the most prominent result was that for wide channels, the number of revolutions until convergence is high. It was seen that smaller channels give higher power coefficients, as predicted by streamtube theory, but the increase in power coefficient with decreasing width was slower, than predicted by streamtube theory. Simulations on a turbine array were performed on five turbines in a row and in a zigzag pattern, where the mean power coefficients of the turbines in the array are higher than for a single turbine. The row configuration was also shown to obtain slightly higher power coefficients and being less sensitive to misalignments in flow direction than the zigzag pattern.

  • 12.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Fluid Mechanics of Vertical Axis Turbines: Simulations and Model Development2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Two computationally fast fluid mechanical models for vertical axis turbines are the streamtube and the vortex model. The streamtube model is the fastest, allowing three-dimensional modeling of the turbine, but lacks a proper time-dependent description of the flow through the turbine. The vortex model used is two-dimensional, but gives a more complete time-dependent description of the flow. Effects of a velocity profile and the inclusion of struts have been investigated with the streamtube model. Simulations with an inhomogeneous velocity profile predict that the power coefficient of a vertical axis turbine is relatively insensitive to the velocity profile. For the struts, structural mechanic loads have been computed and the calculations show that if turbines are designed for high flow velocities, additional struts are required, reducing the efficiency for lower flow velocities.Turbines in channels and turbine arrays have been studied with the vortex model. The channel study shows that smaller channels give higher power coefficients and convergence is obtained in fewer time steps. Simulations on a turbine array were performed on five turbines in a row and in a zigzag configuration, where better performance is predicted for the row configuration. The row configuration was extended to ten turbines and it has been shown that the turbine spacing needs to be increased if the misalignment in flow direction is large.A control system for the turbine with only the rotational velocity as input has been studied using the vortex model coupled with an electrical model. According to simulations, this system can obtain power coefficients close to the theoretical peak values. This control system study has been extended to a turbine farm. Individual control of each turbine has been compared to a less costly control system where all turbines are connected to a mutual DC bus through passive rectifiers. The individual control performs best for aerodynamically independent turbines, but for aerodynamically coupled turbines, the results show that a mutual DC bus can be a viable option.Finally, an implementation of the fast multipole method has been made on a graphics processing unit (GPU) and the performance gain from this platform is demonstrated.

    Fulltekst (pdf)
    fulltext
  • 13.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bülow, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Aerodynamic and electrical evaluation of a VAWT farm control system with passive rectifiers and mutual DC-bus2013Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 60, s. 284-292Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A wind farm with a simple electrical topology with passive rectifiers and a single inverter (mutual topology) is compared to a more complex topology where each turbine has a separate inverter (separate topology).In both cases, the turbines are controlled electrically by varying the extracted power with the rotational velocity as control signal.These two electrical topologies are evaluated with respect to absorbed power for a farm of four turbines placed either on a line or in a square formation.The evaluation is done with an aerodynamic vortex model coupled with an electrical system model.Simulations predict that individual control is beneficial for aerodynamically independent turbines if flow velocities differ significantly between turbines. If the differences in flow velocities are caused by one turbine operating in the wake of another, the deviations in power output between the topologies are less prominent.The mutual topology even deliver more power than the separate topology when one turbine is in the wake of another turbine if the wind speed changes rapidly.

    Fulltekst (pdf)
    fulltext
  • 14.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bülow, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Robust VAWT control system evaluation by coupled aerodynamic and electrical simulations2013Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 59, s. 193-201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A control system for a vertical axis wind turbine is presented.The control strategy is to determine the electric load solely from the rotational velocity and the characteristics of the turbine, thus measurement of the incoming wind velocity is not required.The control system is evaluated with an aerodynamic vortex model coupled with an electrical model.Three different sets of control system parameters are tested, due to the trade off between high power absorption and achieving a fast system with high stability.The control systems are tested against a reference strategy where the wind speed is known.The simulations show that the three control systems provide a similar power absorption as the reference case.For dynamic cases, with fast changes in wind speed, the fast control strategies are beneficial.All control strategies are stable throughout the simulations when proper power absorption characteristics of the turbine are used. It is also shown that if peak power absorption is estimated at a too low tip speed ratio, the control strategies may inadvertently stop the turbine.

  • 15.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Engblom, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för beräkningsvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Tillämpad beräkningsvetenskap.
    A general high order two-dimensional panel method2018Inngår i: Applied Mathematical Modelling, ISSN 0307-904X, E-ISSN 1872-8480, Vol. 60, s. 1-17Artikkel i tidsskrift (Fagfellevurdert)
  • 16.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Engblom, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för beräkningsvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Tillämpad beräkningsvetenskap.
    Adaptive fast multipole methods on the GPU2013Inngår i: Journal of Supercomputing, ISSN 0920-8542, E-ISSN 1573-0484, Vol. 63, s. 897-918Artikkel i tidsskrift (Fagfellevurdert)
  • 17.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Engblom, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för beräkningsvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Tillämpad beräkningsvetenskap.
    Adaptive fast multipole methods on the GPU2012Rapport (Annet vitenskapelig)
  • 18.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lalander, Emilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Influence of a Varying Vertical Velocity Profile on Turbine Efficiency for a Vertical Axis Marine Current Turbine,2009Konferansepaper (Fagfellevurdert)
  • 19.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lundin, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    A parameter study of the influence of struts on the performance of a vertical-axis marine current turbine.2009Konferansepaper (Fagfellevurdert)
  • 20.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Rossander, Morgan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Force measurements on a VAWT blade in parked conditions2017Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 10, nr 12, artikkel-id 1954Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The forces on a turbine at extreme wind conditions when the turbine is parked is one of the most important design cases for the survivability of a turbine. In this work, the forces on a blade and its support arms have been measured on a 12 kW straight-bladed vertical axis wind turbine at an open site. Two cases are tested: one during electrical braking of the turbine, which allows it to rotate slowly, and one with the turbine mechanically fixed with the leading edge of the blade facing the main wind direction. The force variations with respect to wind direction are investigated, and it is seen that significant variations in forces depend on the wind direction. The measurements show that for the fixed case, when subjected to the same wind speed, the forces are lower when the blade faces the wind direction. The results also show that due to the lower forces at this particular wind direction, the average forces for the fixed blade are notably lower. Hence, it is possible to reduce the forces on a turbine blade, simply by taking the dominating wind direction into account when the turbine is parked. The measurements also show that a positive torque is generated from the blade for most wind directions, which causes the turbine to rotate in the electrically-braked case. These rotations will cause increased fatigue loads on the turbine blade.

    Fulltekst (pdf)
    fulltext
  • 21.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Uzunoglu, Bahri
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Giovannini, Gabriele
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Magdalena, J.
    Fernandez, A.
    A GUI for urban wind flow CFD analysis of small scale wind applications2015Inngår i: Cyberworlds, 2015 IEEE, 2015, s. 193-199Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In order to have better insight into the physics of the urban wind turbines, a graphical user interface (GUI) that employs OpenFOAM flow solver has been developed for industrial applications by Uppsala University with Spanish engineering company SOLUTE via EU framework as part of the WINDUR framework 7 project. Urban wind resource assessment for small scale wind applications present several challenges and complexities for that are different from large-scale wind power generation. Urban boundary layer relevant in this regime of flows have different horizontal profiles impacted by the buildings, low speed wind regimes, separation and different turbulence characteristics. This software addresses the project setup and scientific visualization of the results for right investment decision needs. Preliminary numerical results will be presented for a test site in Huesca, Spain where a measurement campaign is undertaken to validate the Computational Fluid Dynamics (CFD) results.

  • 22.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Ågren, Olov
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Numerical Simulation of a Farm of Vertical Axis Marine Current Turbines2010Inngår i: PROCEEDINGS OF THE ASME 29TH INTERNATIONAL CONFERENCE ON OCEAN, OFFSHORE AND ARCTIC ENGINEERING 2010, VOL 3, 2010, s. 335-344Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For commercial applications of marine current turbines, it can be useful to build several turbines close to each other in a farm, similar to wind turbine parks. To create a good farm configuration, the turbines' mutual interaction needs to be studied. Here, to obtain detailed information, several turbines were simulated together using a 2D vortex method. To limit the computational cost, the vortex method was combined with known profile section data for the blades.

    First, a single turbine was compared against two turbines in close proximity. The two turbines were tested both with equal and opposite rotational direction, and the two blade pitch angles 0 and 3 degrees were tested. For both a single turbine and the two turbine case, a 3 degree pitch angle gave higher power coefficients than 0 degrees. The differences between 3 and 0 degrees were more significant for the single turbine. In all cases, the two turbine system had higher power coefficient per turbine than the single turbine.

    A five turbine park was simulated with three different combinations, one with all turbines on a row, and two with a zigzag pattern, where the difference was that the last simulation had larger turbines than the other two. For 0 degrees incident flow angle, the turbines on the row obtained the highest power coefficient, while the larger turbines in zigzag pattern obtained higher total power. The case with the turbines on the row was most insensitive to changes in flow direction, and for a 30 degree change, the row produced the highest total power as well. By locating the turbines inside a channel, all turbines obtained higher power coefficients, and the increase was largest for the large turbines, which blocked the channel to a larger extent.

  • 23.
    Goude, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Ågren, Olov
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Simulations of a vertical axis turbine in a channel2014Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 63, s. 477-485Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The power coefficient of a turbine increases according to the predictions from streamtube theory for sites with a confined fluid flow. Here, a vertical axis turbine (optimized for free flow) has been simulated by a two-dimensional vortex method, both in a channel and in free flow. The first part of the study concerns the numerical parameters of channel simulations. It is found that for free flow and wide channels, a large number of revolutions is required for convergence (around 100 at the optimal tip speed ratio and increasing with higher tip speed ratio), while for smaller channels, the required number of revolutions decreases. The second part analyses changes in turbine performance by the channel boundaries. The turbine performance increases when the channel width is decreased, although the results are below the predictions from streamtube theory, and this difference increases with decreasing channel width. It is also observed that the optimal tip speed ratio increases with decreasing channel width. By increasing the chord, which decreases the optimal tip speed ratio, the power coefficient can be increased somewhat.

  • 24.
    Grabbe, Mårten
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Yuen, Katarina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lalander, Emilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Design of an experimental setup for hydro-kinetic energy conversion2009Inngår i: International Journal on Hydropower & Dams, ISSN 1352-2523, Vol. 16, nr 5, s. 112-116Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A hydro-kinetic energy project has been underway in Sweden since 2000, and an in-stream prototype setup for experiments at a site in a Swedish river is now in progress. The system comprises a vertical axis turbine and a directly driven permanent magnet generator. Methods and choices used in designing the system are described here. The turbine and generator are evaluated based on measurements and CFD simulations of conditions at the site for the experimental setup.

    Fulltekst (pdf)
    FULLTEXT02
  • 25.
    Holm, Marcus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för beräkningsvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Tillämpad beräkningsvetenskap.
    Engblom, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för beräkningsvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Tillämpad beräkningsvetenskap.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Holmgren, Sverker
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för beräkningsvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Tillämpad beräkningsvetenskap.
    Dynamic autotuning of adaptive fast multipole methods on hybrid multicore CPU and GPU systems2014Inngår i: SIAM Journal on Scientific Computing, ISSN 1064-8275, E-ISSN 1095-7197, Vol. 36, s. C376-C399Artikkel i tidsskrift (Fagfellevurdert)
  • 26.
    Lundin, Staffan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Forslund, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Carpman, Nicole
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Grabbe, Mårten
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Yuen, Katarina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Apelfröjd, Senad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    The Söderfors Project: Experimental Hydrokinetic Power Station Deployment and First Results2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Division of Electricity at Uppsala University recently deployed an experimental hydrokinetic power station for in-stream experiments at a site in a river. This paper briefly describes the deployment process and reports some initial results from measurements made at the test site.

    Fulltekst (pdf)
    Söderfors_published
  • 27.
    Lundin, Staffan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Forslund, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Grabbe, Mårten
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Yuen, Katarina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Experimental demonstration of performance of a vertical axis marine current turbine in a river2016Inngår i: Journal of Renewable and Sustainable Energy, ISSN 1941-7012, E-ISSN 1941-7012, Vol. 8, nr 6, artikkel-id 064501Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An experimental station for marine current power has been installed in a river. The station comprises a vertical axis turbine with a direct-driven permanent magnet synchronous generator. In measurements of steady-state operation in varying flow conditions, performance comparable to that of turbines designed for significantly higher flow speeds is achieved, demonstrating the viability of electricity generation in low speed (below 1.5 m/s) marine currents.

    Fulltekst (pdf)
    fulltext
  • 28.
    Lundin, Staffan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    One-Dimensional Modelling of Marine Current Turbine Runaway Behaviour2016Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 9, nr 5, artikkel-id 309Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    If a turbine loses its electrical load, it will rotate freely and increase speed, eventually achieving that rotational speed which produces zero net torque. This is known as a runaway situation. Unlike many other types of turbine, a marine current turbine will typically overshoot the final runaway speed before slowing down and settling at the runaway speed. Since the hydrodynamic forces acting on the turbine are dependent on rotational speed and acceleration, turbine behaviour during runaway becomes important for load analyses during turbine design. In this article, we consider analytical and numerical models of marine current turbine runaway behaviour in one dimension. The analytical model is found not to capture the overshoot phenomenon, while still providing useful estimates of acceleration at the onset of runaway. The numerical model incorporates turbine wake build-up and predicts a rotational speed overshoot. The predictions of the models are compared against measurements of runaway of a marine current turbine. The models are also used to recreate previously-published results for a tidal turbine and applied to a wind turbine. It is found that both models provide reasonable estimates of maximum accelerations. The numerical model is found to capture the speed overshoot well.

    Fulltekst (pdf)
    fulltext
  • 29.
    Mendoza, Victor
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bachant, Peter
    WindESCo Inc, Boston, MA USA.
    Ferreira, Carlos
    Delft Univ Technol, Wind Energy Res Inst, TU Delft, Delft, Netherlands.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Near-Wake Flow Simulation of a Vertical Axis Turbine Using an Actuator Line Model2019Inngår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824, Vol. 22, nr 2, s. 171-188Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present work, the near‐wake generated for a vertical axis wind turbine (VAWT) was simulated using an actuator line model (ALM) in order to validate and evaluate its accuracy. The sensitivity of the model to the variation of the spatial and temporal discretization was studied and showed a bigger response to the variation in the mesh size as compared with the temporal discretization. The large eddy simulation (LES) approach was used to predict the turbulence effects. The performance of Smagorinsky, dynamic k‐equation, and dynamic Lagrangian turbulence models was tested, showing very little relevant differences between them. Generally, predicted results agree well with experimental data for velocity and vorticity fields in representative sections. The presented ALM was able to characterize the main phenomena involved in the flow pattern using a relatively low computational cost without stability concerns, identified the general wake structure (qualitatively and quantitatively), and the contribution from the blade tips and motion on it. Additionally, the effects of the tower and struts were investigated with respect to the overall structure of the wake, showing no significant modification. Similarities and discrepancies between numerical and experimental results are discussed. The obtained results from the various simulations carried out here can be used as a practical reference guideline for choosing parameters in VAWTs simulations using the ALM.

  • 30.
    Mendoza, Victor
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bachant, Peter
    Center for Ocean Renewable Energy, University of New Hampshire, 24 Colovos Rd., Durham, NH 03824, USA.
    Wosnik, Martin
    Center for Ocean Renewable Energy, University of New Hampshire, 24 Colovos Rd., Durham, NH 03824, USA.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines2016Inngår i: Science Of Making Torque From Wind (Torque 2016) / [ed] IOP, 2016, artikkel-id 022043Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Vertical axis wind turbines (VAWT) can be used to extract renewable energy from wind flows. A simpler design, low cost of maintenance, and the ability to accept flow from all directions perpendicular to the rotor axis are some of the most important advantages over conventional horizontal axis wind turbines (HAWT). However, VAWT encounter complex and unsteady fluid dynamics, which present significant modeling challenges. One of the most relevant phenomena is dynamic stall, which is caused by the unsteady variation of angle of attack throughout the blade rotation, and is the focus of the present study. Dynamic stall is usually used as a passive control for VAWT operating conditions, hence the importance of predicting its effects. In this study, a coupled model is implemented with the open-source CFD toolbox OpenFOAM for solving the Navier-Stokes equations, where an actuator line model and dynamic stall model are used to compute the blade loading and body force. Force coefficients obtained from the model are validated with experimental data of pitching airfoil in similar operating conditions as an H-rotor type VAWT. Numerical results show reasonable agreement with experimental data for pitching motion.

    Fulltekst (pdf)
    fulltext
  • 31.
    Mendoza, Victor
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Chaudhari, Ashvinkumar
    Lappeenranta Univ Technol, Sch Engn Sci, CEID, Lappeenranta, Finland.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Performance and wake comparison of horizontal and vertical axis wind turbines under varying surface roughness conditions2019Inngår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824, Vol. 22, nr 4, s. 458-472Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A numerical study of both a horizontal axis wind turbine (HAWT) and a vertical axis wind turbine (VAWT) with similar size and power rating is presented. These large scale turbines have been tested when operating stand-alone at their optimal tip speed ratio (TSR) within a neutrally stratified atmospheric boundary layer (ABL). The impact of three different surface roughness lengths on the turbine performance is studied for the both turbines. The turbines performance, the response to the variation in the surface roughness of terrain, and the most relevant phenomena involved on the resulting wake were investigated. The main goal was to evaluate the differences and similarities of these two different types of turbine when they operate under the same atmospheric flow conditions. An actuator line model (ALM) was used together with the large eddy simulation (LES) approach for predicting wake effects, and it was implemented using the open-source computational fluid dynamics (CFD) library OpenFOAM to solve the governing equations and to compute the resulting flow fields. This model was first validated using wind tunnel measurements of power coefficients and wake of interacting HAWTs, and then employed to study the wake structure of both full scale turbines. A preliminary study test comparing the forces on a VAWT blades against measurements was also investigated. These obtained results showed a better performance and shorter wake (faster recovery) for an HAWT compared with a VAWT for the same atmospheric conditions.

  • 32.
    Mendoza, Victor
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Improving farm efficiency of interacting vertical‐axis wind turbines through wake deflection using pitched struts2019Inngår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824, Vol. 22, nr 4, s. 538-546Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work presents a numerical study of the obtained performance and the resulting flow field between two interacting large scale vertical-axis wind turbines (VAWTs), under the influence of a deflected wake through the struts pitching of the upwind turbine. The configuration consists of two VAWTs aligned in the direction of the incoming flow in which a wide range of fixed struts pitching angles in the upwind turbine have been investigated. The main goal is to evaluate the influence of the wake deflection on the turbines performance while they are operating at their optimal tip speed ratio (TSR), and to reproduce the most relevant phenomena involved in the flow pattern of the interacting wake. Arrangements with cross-stream offsets have also been tested for quantifying the contribution of this modification into the overall performance. For this purpose, an actuator line model (ALM) has been implemented using the open-source CFD library OpenFOAM in order to solve the governing equations and to calculate the resulting flow. The Large eddy simulation (LES) approach is considered to reproduce the turbulence flow effects. A preliminary study to identify the optimal TSR of the interacting downwind turbine has been investigated.

  • 33.
    Mendoza, Victor
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Validation of Actuator Line and Vortex Models using Normal Forces Measurements of a Straight-Bladed Vertical Axis Wind Turbine2020Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 13, nr 3, artikkel-id 511Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Vertical Axis Wind Turbines (VAWTs) are characterized by complex and unsteady flow patterns resulting in considerable challenges for both numerical simulations and measurements describing the phenomena involved. In this study, a 3D Actuator Line Model (ALM) is compared to a 2D and a 3D Vortex Model, and they are validated using the normal forces measurements on a blade of an operating 12 kW VAWT, which is located in an open site in the north of Uppsala, Sweden. First, the coefficient power ( Cp ) curve of the device has been simulated and compared against the experimental one. Then, a wide range of operational conditions for different tip speed ratios (TSRs), with λ = 1.84, 2.55, 3.06, 3.44, 4.09 and 4.57 were investigated. The results showed descent agreement with the experimental data for both models in terms of the trend and magnitudes. On one side, a slight improvement for representing the normal forces was achieved by the ALM, while the vortex code performs better in the simulation of the Cp curve. Similarities and discrepancies between numerical and experimental results are discussed.

    Fulltekst (pdf)
    fulltext
  • 34.
    Mendoza, Victor
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines2016Konferansepaper (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 35.
    Mendoza, Victor
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Wake Flow Simulation of a Vertical Axis Wind Turbine Under the Influence of Wind Shear2017Inngår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 854, artikkel-id 012031Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The current trend of the wind energy industry aims for large scale turbines installed in wind farms. This brings a renewed interest in vertical axis wind turbines (VAWTs) since they have several advantages over the traditional Horizontal Axis Wind Tubines (HAWTs) for mitigating the new challenges. However, operating VAWTs are characterized by complex aerodynamics phenomena, presenting considerable challenges for modeling tools. An accurate and reliable simulation tool for predicting the interaction between the obtained wake of an operating VAWT and the flow in atmospheric open sites is fundamental for optimizing the design and location of wind energy facility projects. The present work studies the wake produced by a VAWT and how it is affected by the surface roughness of the terrain, without considering the effects of the ambient turbulence intensity. This study was carried out using an actuator line model (ALM), and it was implemented using the open-source CFD library OpenFOAM to solve the governing equations and to compute the resulting flow fields. An operational H-shaped VAWT model was tested, for which experimental activity has been performed at an open site north of Uppsala-Sweden. Different terrains with similar inflow velocities have been evaluated. Simulated velocity and vorticity of representative sections have been analyzed. Numerical results were validated using normal forces measurements, showing reasonable agreement.

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  • 36.
    Möllerström, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära. Department of Construction and Energy Engineering, Halmstad University, PO Box 823, SE-301 18 Halmstad, Sweden.
    Eriksson, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Ottermo, Fredric
    Department of Construction and Energy Engineering, Halmstad University, PO Box 823, SE-301 18 Halmstad, Sweden.
    Hylander, Jonny
    Department of Construction and Energy Engineering, Halmstad University, PO Box 823, SE-301 18 Halmstad, Sweden.
    Turbulence influence on optimum tip speed ratio for a 200 kW vertical axis wind turbine2016Inngår i: Science Of Making Torque From Wind (Torque 2016) / [ed] IOP, 2016, Vol. 753, artikkel-id 032048Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The influence of turbulence intensity (TI) on the tip speed ratio for maximum power coefficient, here called λCp-max, is studied for a 200 kW VAWT H-rotor using logged data from a 14 month period with the H-rotor operating in wind speeds up to 9 m/s. The TI - λCp-max relation is examined by dividing 10 min mean values in different turbulence intensity ranges and producing multiple CP(λ) curves. A clear positive relation between TI and λCp-max is shown and is further strengthened as possible secondary effects are examined and deemed non-essential. The established relation makes it possible to tune the control strategy to enhance the total efficiency of the turbine.

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    fulltext
  • 37.
    Möllerström, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära. Halmstad Univ, Dept Construct & Energy Engn, POB 823, SE-30118 Halmstad, Sweden.
    Ottermo, Fredric
    Halmstad Univ, Dept Construct & Energy Engn, POB 823, SE-30118 Halmstad, Sweden.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Eriksson, Sandra S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Hylander, Jonny
    Halmstad Univ, Dept Construct & Energy Engn, POB 823, SE-30118 Halmstad, Sweden.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Turbulence influence on wind energy extraction for a medium size vertical axis wind turbine2016Inngår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824, Vol. 19, nr 11, s. 1963-1973Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The relation between power performance and turbulence intensity for a VAWT H-rotor is studied using logged data from a 14 month (discontinuous) period with the H-rotor operating in wind speeds up to 9 m/s. The turbine, designed originally fora nominal power of 200 kW, operated during this period mostly in a restricted mode due to mechanical concerns, reachingpower levels up to about 80 kW. Two different approaches are used for presenting results, one that can be compared topower curves consistent with the International Electrotechnical Commission (IEC) standard and one that allows isolatingthe effect of turbulence from the cubic variation of power with wind speed. Accounting for this effect, the turbine stillshows slightly higher efficiency at higher turbulence, proposing that the H-rotor is well suited for wind sites with turbulentwinds. The operational data are also used to create a Cp(λ) curve, showing slightly lower Cp compared with a curvesimulated by a double multiple streamtube model.

  • 38.
    Nguyen, Minh-Thao
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Balduzzi, Francesco
    Univ Firenze, Dept Ind Engn DIEF, I-50139 Florence, Italy.
    Bianchini, Alessandro
    Univ Firenze, Dept Ind Engn DIEF, I-50139 Florence, Italy.
    Ferrara, Giovanni
    Univ Firenze, Dept Ind Engn DIEF, I-50139 Florence, Italy.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Evaluation of the unsteady aerodynamic forces acting on a vertical-axis turbine by means of numerical simulations and open site experiments2020Inngår i: Journal of Wind Engineering and Industrial Aerodynamics, ISSN 0167-6105, E-ISSN 1872-8197, Vol. 198, artikkel-id 104093Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An increasing number of vertical-axis wind turbine prototypes have reached the step in which the theoretically predicted performance needs to be validated in order to move to the next steps of a real commercial project. This step often faces the significant challenges posed by their airfoil aerodynamics that are more complex than those of conventional horizontal-axis wind turbines, and it has also to deal with the lack of fundamental experimental data for robust validation. In this context, an accurate prediction of the real turbine operation is important and the use of computational fluid dynamics (CFD) is imposing itself as the most suitable tool to characterize the unsteady phenomena that are difficult to detect by means of experimental measurements. In the current work, two-dimensional numerical simulations of an H-type three-blade Darrieus turbine have been performed in a wide range of tip-speed ratios (TSRs) from TSR = 1.8 to TSR = 5.0. Unsteady CFD simulations were compared with unique experimental data collected in the field in terms of normal aerodynamic forces acing on the blades during the revolution. Generally, nice agreement was found between simulations and experiments, especially at medium-high tip-speed ratios. The influence of operating conditions on the performance prediction capability of the numerical model was also discussed. This is one of the key points of study since the lack of detailed experimental data often makes numerical analyses doubtful or scarcely effective. Finally, the simulation results were exploited in order to analyze the phenomena occurring during the revolution and to correlate them with the experimental findings.

  • 39.
    Nguyen, Minh-Thao
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Forslund, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Thomas, Karin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Fault analysis of a marine current vertical-axis turbine missing two blades2019Konferansepaper (Fagfellevurdert)
  • 40.
    Nguyen, Van Dang
    et al.
    KTH Royal Inst Technol, Sch Comp Sci & Commun, Dept Computat Sci & Technol, Stockholm, Sweden.
    Jansson, Johan
    KTH Royal Inst Technol, Sch Comp Sci & Commun, Dept Computat Sci & Technol, Stockholm, Sweden; Basque Ctr Appl Math, Bilbao, Spain.
    Leoni, Massimiliano
    Basque Ctr Appl Math, Bilbao, Spain.
    Janssen, Barbel
    KTH Royal Inst Technol, Sch Comp Sci & Commun, Dept Computat Sci & Technol, Stockholm, Sweden.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Hoffman, Johan
    KTH Royal Inst Technol, Sch Comp Sci & Commun, Dept Computat Sci & Technol, Stockholm, Sweden.
    Modelling Of Rotating Vertical Axis Turbines Using A Multiphase Finite Element Method2017Inngår i: VII International Conference on Computational Methods in Marine Engineering (MARINE 2017) / [ed] Visonneau, Michael; Queutey, Patrick & Le Touzé, David, International Center for Numerical Methods in Engineering (CIMNE) , 2017, s. 950-959Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We combine the unified continuum fluid-structure interaction method with a multiphase flow model to simulate turbulent flow and fluid-structure interaction of rotating vertical axis turbines in offshore environments. This work is part of a project funded by the Swedish Energy Agency, which focuses on energy systems combining ecological sustainability, competitiveness and reliability of supply. The numerical methods used comprise the Galerkin least-squares finite element method, coupled with the arbitrary Lagrangian-Eulerian method, in order to compute weak solutions of the Navier-Stokes equations for high Reynolds numbers on moving meshes. Mesh smoothing methods help to improve the mesh quality when the mesh undergoes large deformations. The simulations have been performed using the Unicorn solver in the FEniCS-HPC framework, which runs on supercomputers with near optimal weak and strong scaling up to thousands of cores.

  • 41. Nguyen, Van-Dang
    et al.
    Jansson, Johan
    KTH Royal Inst Technol, Dept Computat Sci & Technol, Stockholm, Sweden.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Hoffman, Johan
    KTH Royal Inst Technol, Dept Computat Sci & Technol, Stockholm, Sweden.
    Direct Finite Element Simulation of the turbulent flow past a vertical axis wind turbine2019Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 135, s. 238-247Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There is today a significant interest in harvesting renewable energy, specifically wind energy, in offshore and urban environments. Vertical axis wind turbines get increasing attention since they are able to capture the wind from any direction. They are relatively easy to install and to transport, cheaper to build and maintain, and quite safe for humans and birds. Detailed computer simulations of the fluid dynamics of wind turbines provide an enhanced understanding of the technology and may guide design improvements. In this paper, we simulate the turbulent flow past a vertical axis wind turbine for a range of rotation angles in parked and rotating conditions. We propose the method of Direct Finite Element Simulation in a rotating ALE framework, abbreviated as DFS-ALE. The simulation results are validated against experimental data in the form of force measurements. It is found that the simulation results are stable with respect to mesh refinement and that the general shape of the variation of force measurements over the rotation angles is captured with good agreement.

  • 42.
    Olauson, Jon
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Ayob, Nasir
    Bergkvist, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Carpman, Nicole
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Castellucci, Valeria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lingfors, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    A highly/fully renewable Nordic power system: Which type of variability would hydropower need to deal with?2015Annet (Annet vitenskapelig)
  • 43.
    Olauson, Jon
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bergkvist, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Wind Energy Converters and Photovoltaics for Generation of Electricity after Natural Disasters2015Inngår i: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 97, nr 1, s. 9-23Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During recovery and reconstruction after a natural disaster, an autonomous power supply might be needed for an extended period of time. In this work, the feasibility of using small-scale wind power and battery storage for power supply is evaluated and compared with systems containing photovoltaics. The investment cost per yearly produced kWh and for an optimized energy system supplying small loads (2 or 20 kW peak) has been calculated for 32 sites, predominantly in Africa and the Middle East. The sites represent foreign activities of the Swedish Civil Contingencies Agency at the end of 2012.

    Since wind speed measurement series often have a lot of missing data, autoregressive moving average models were trained and used to generate hourly time series of wind speed. This methodology proved robust, even when data availability was very low or when measurements were only taken every third hour. The results of the simulations show that photovoltaic/battery systems outperform wind/battery systems at all evaluated sites. This can be explained by lower investment cost per yearly produced kWh and smoother daily/weekly power output over the year for the photovoltaic system. The proportion of wind power for optimized systems comprising wind, photovoltaics and battery bank is generally very low and the system cost is almost identical to the corresponding photovoltaic/battery systems. In conclusion, at lower latitudes and with little time for a proper wind measurement campaign, photovoltaics should be the primary candidate for replacing or complementing conventional diesel generators.

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  • 44.
    Rossander, Morgan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Dyachuk, Eduard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Apelfröjd, Senad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Trolin, Kristian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Eriksson, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Evaluation of a Blade Force Measurement System for a Vertical Axis Wind Turbine Using Load Cells2015Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, nr 6, s. 5973-5996Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Unique blade force measurements on an open site straight-bladed vertical axis wind turbine have been performed. This paper presents a method for measuring the tangential and normal forces on a 12-kW vertical axis wind turbine prototype with a three-bladed H-rotor. Four single-axis load cells were installed in-between the hub and the support arms on one of the blades. The experimental setup, the measurement principle, together with the necessary control and measurement system are described. The maximum errors of the forces and accompanying weather data that can be obtained with the system are carefully estimated. Measured forces from the four load cells are presented, as well as the normal and tangential forces derived from them and a comparison with theoretical data. The measured torque and bending moment are also provided. The influence of the load cells on the turbine dynamics has also been evaluated. For the aerodynamic normal force, the system provides periodic data in agreement with simulations. Unexpected mechanical oscillations are present in the tangential force, introduced by the turbine dynamics. The measurement errors are of an acceptable size and often depend on the measured variable. Equations are presented for the calculation of measurement errors.

  • 45.
    Rossander, Morgan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Eriksson, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Frequency analysis of tangential force measurements on a vertical axis wind turbine2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents experimental results of the torque ripple obtained from a three bladed 12 kW experimental H-rotor prototype. The measurements are performed by means of load cells installed on the base of the struts and by electrical measurements on the generator. The resulting torques are analysed in terms of frequency spectrum and order spectrum (synchronized with rotation). The measurements are compared to aerodynamic simulations of the turbine. The expected large torque ripple at three times the rotational speed (3 p) is only weakly represented at the hub and in the generator. This suggests that the system is filtering the ripple and/or that the simulations are overestimating the 3 p component. The torque ripple loads on the drive train are therefore lower than anticipated. Even if highly attenuated, most of the low frequencies correlating to aerodynamics are still represented in the generator electrical torque. Given a certain baseline, this opens for possible online monitoring of unbalances in the turbine by electrical measurements.

    Fulltekst (pdf)
    fulltext
  • 46.
    Rossander, Morgan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Eriksson, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Critical Speed Control for a Fixed Blade Variable Speed Wind Turbine2017Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 10, nr 11, artikkel-id 1699Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A critical speed controller for avoiding a certain rotational speed is presented. The controller is useful for variable speed wind turbines with a natural frequency in the operating range. The controller has been simulated, implemented and tested on an open site 12 kW vertical axis wind turbine prototype. The controller is based on an adaptation of the optimum torque control. Two lookup tables and a simple state machine provide the control logic of the controller. The controller requires low computational resources, and no wind speed measurement is needed. The results suggest that the controller is a feasible method for critical speed control. The skipping behavior can be adjusted using only two parameters. While tested on a vertical axis wind turbine, it may be used on any variable speed turbine with the control of generator power.

    Fulltekst (pdf)
    fulltext
  • 47.
    Rossander, Morgan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Eriksson, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Mechanical torque ripple from a passive diode rectifier in a 12 kW vertical axis wind turbine2017Inngår i: IEEE transactions on energy conversion, ISSN 0885-8969, E-ISSN 1558-0059, Vol. 32, nr 1, s. 164-171Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of passive rectification on the mechanical torque of a permanent magnet generator for a directly driven vertical axis wind turbine has been studied. Passive diode rectification introduce electromagnetic torque ripple from the generator. The conversion of electromagnetic torque ripple into mechanical torque ripple and rotational speed ripple has been modeled, analytically evaluated, and simulated. The simulations have been compared to measurements on an open site 12 kW prototype. A parameter study with the model illustrates the impact of shaft torsional spring constant, generator rotor inertia, generator inductance, and dc-link capacitance. The results show that the shaft and generator rotor can be an effective filter of electromagnetic torque ripple from diode rectification. The measured mechanical torque ripple amplitude on the prototype is less than +/- 0.9% of nominal turbine torque. The measurements compare well with the simulations.

    Fulltekst (pdf)
    fulltext
  • 48.
    Yuen, Katarina
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lundin, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Grabbe, Mårten
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lalander, Emilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    The Söderfors Project: Construction of an Experimental Hydrokinetic Power Station2011Inngår i: Proceedings of the 9th European Wave and Tidal Energy Conference, Southampton, UK, 5-9 September 2011, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Division of Electricity at Uppsala Universityis developing an experimental hydrokinetic power station for instreamexperiments at a site in a river. The purpose of this paperis to present some of the design choices made in the constructionof the experimental station. For background purposes, an outlineof the research project as a whole is also given.

    The experimental station will be deployed in the Dal¨alvenRiver at S¨oderfors, whence the project derives its name. Thesite was selected based on several technical and non-technicalreasons. The system comprises a vertically oriented cross-streamaxis turbine and a directly driven permanent magnet generator tobe situated on the riverbed. The necessary power electronics forcontrol and power conversion will be housed in a small measuringstation on shore.

    The paper discusses several aspects of the project, thatmight be of interest to other researchers in the field. Variousdesign choices, where different properties become the limiting ordeciding factor in different cases, are discussed along with theirrespective advantages and disadvantages. A brief outlook as tothe future of the project is also given.

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