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In wind energy systems, it is necessary to have a good knowledge of the used generator and its parameters. Despite the motor manufacturer's specifications, accurately estimating the machine parameter reference values is critical for the perfect control system. In this context, off-line identification tests of a 3 kW permanent magnet synchronous machine were conducted to determine the mechanical and electrical parameters. In addition, this research exploits a meta-heuristic optimization technic dubbed grey wolf optimizer in the on-line parameter's identification field. The estimate method is focused on the parameter's estimation linked to a reference model. The rule is based on the cancelation of the current error among the measured and the associated estimated current. For each measurement, the grey wolf estimator adapts the reference model parameters until the model response and the accurate response be similar. All were implemented using the real-time interface of the DSpace DS1104 Controller card while using the ControlDesk graphical user interface and the Simulink/MATLAB environments. Results from hardware simulation confirm the efficacy and benefits of the suggested strategy. [ABSTRACT FROM AUTHOR]

The current study proposed a robust sensor-less sliding mode second-order based on a super twisting algorithm (STA-SMSO) approach using a new observer Model Reference Adaptive System-Adaptative Neuro-Fuzzy Inference System (MRAS-ANFIS). This model was applied to a doubly fed induction generator (DFIG) wind turbine running under variable wind speed and DFIG fed with a power voltage source without a speed sensor, while the control objective was used to regulate independently, the active and reactive power DFIG stator were decoupled by using the field-oriented control technique. Additionally, this process reduced the cost of the control scheme and the size of DFIG by eliminating the speed sensor (encoder). In order to improve the traditional MRAS, the MRAS-ANFIS observer was proposed to replace the usual PI controller in the adaptation mechanism of MRAS with an Adaptative Neuro-Fuzzy Inference System (ANFIS) controller. The estimation of rotor position was tested and discussed under varying load conditions in low, zero, and high-speed region. The results mentioned that the proposed observer (MRAS-ANFIS) presented an attractive feature, such as guarantees finite time convergence, good response on speed wind variations, high robustness against machine parameter variations, and load variations compared to the conventional MRAS observer and MRAS-Fuzzy. Hence, the estimated rotor speed converged to their actual value has the capacity for estimating position in deferent region (low/zero/high) of speed. [ABSTRACT FROM AUTHOR]

Mast structure is one of the most important parts of a vertical-axis wind turbine which supports generator and rotor and represents one-third of the overall costs in the production of a standard wind turbine (approximately 30%). All this may cause significant economic and physical losses when it is damaged or collapsed. The purpose of this research is to investigate numerically the static strength and structural dynamic responses of 10-kW vertical-axis wind turbine masts subjected to the aerodynamic and gravity loadings (according to the IEC 61400-2:2006 and EN 1991-1-4:2005 standards) using the SolidWorks finite element software. Mast structures with four different heights (12, 14, 16, and 18 m) and three various outer diameters (0.6, 0.7, and 0.8 m), in each height configuration, were evaluated. These analyses were performed to identify the stiffness, resistance, reliability, and natural frequency stiffness requirements within the mast structures, in order to save manufacturing cost. Based on static analysis, no structural failure is predicted for all masts during wind turbine operation according to maximum von Mises stresses at the bottom of the mast and maximum total deflections on the top of the mast. In addition, the dynamic parameters of these 12 models of masts have been studied to obtain the natural frequencies and corresponding mode shapes. Finally, the recommendations to avoid resonance and design strategy for each mast model are discussed. [ABSTRACT FROM AUTHOR]

Small H-Darrieus wind turbines have become popular in the wind power market because of their many advantages, which include simplicity of design, low construction costs, and they are thought to represent an adequate solution even in unconventional installation regions. The blade is generally considered as the most important component of the wind turbine system because it controls the efficiency of the turbine. The blade structure must be designed to support the difficult environmental conditions (e.g., wind, and snow) encountered during the operational life of the wind turbine. This current study uses three-dimensional (3D) modeling and structural strength analysis to fabricate two straight blades (aluminum and galvanized steel) for a small H-Darrieus wind turbine. The 3D modeling of the blade structure is performed using SolidWorks, a computer-aided design (CAD) software package, and the structural strength analysis uses the Finite Element Analysis (FEA) technique to identify the stiffness, resistance, and reliability of the blade structure. The simulation results obtained indicate that no structural failures are predicted for either of the two structures tested because the factors of safety are larger than one, and the all maximum deflections are within the allowable deformation limits for the materials. Manufacturing processes for the two structures are described. [ABSTRACT FROM AUTHOR]

The output wind power curve versus wind speed is the most important characterization parameter of wind turbines. It allows quantifying and analyzing the design performances of wind turbines, monitoring its database, and controlling the operation modes and manufacturing products. Wind power curve can be used to select the proper rotor size to estimate the potential of wind energy at candidate wind sites and to assess the control device of the operating conditions. Developing model strategies for wind farms has the basic objectives such as the optimization of wind power produced and the minimization of dynamic loads to provide the best quality of output wind power at reasonable cost. Optimal design of wind turbines requires maximum-closing to the cubical output wind power curve despite technical and economic considerations. This study aims to determine the design wind speed of a wind turbine based on modeling-optimization of the output wind power curve under certain working conditions. The procedure is applied to a unit wind turbine in Gamesa wind farm (G52/850, 10.2 MW, http://www.thewindpower.net) connected to an electrical grid located in south-west Algeria and extrapolated for other windy sites in Algeria. From simulation results, the design wind speed to inlet wind speed ratio V d / V in = [ 3 / (3 − a) ] 1 / a increased from 0.35 to 7.68 once a increased from 0.001 to 2.9999. Consequently, the output wind power predicted an increase of about 17.7% and an annual specific wind energy factor of about 2.55%–4% than nominal value given by the manufacturer, reducing the unit average cost of the electricity, generated by wind farms, by about 18.75%. [ABSTRACT FROM AUTHOR]

The study deals with the numerical analysis aspects that are necessary for identifying of modal parameters of the tower structure as the most important part of the horizontal axis wind turbine, which are basic for the dynamic response analysis. In the present study, the modal behavior of an actual 55-m-high steel tower of 850 KW wind turbine (GAMESA G52/850 model) is investigated by using three-dimensional (3D) Finite Element (FE) method. The model was used to identify natural frequencies, their corresponding mode shapes and mass participation ratios, and the suggestions to avoid resonance for tower structure under the action wind. The results indicate that there is a very good agreement with the fundamental vibration theory of Euler-Bernoulli beam with lamped masse in bending vibration modes. When the rotor of the wind turbine runs at the speed of less than or equal to 25.9 rpm it will not have resonant problems (stiff–stiff tower design). Furthermore, in case the rotor runs at the speed of between 25.9 and 30.8 rpm, the adequate controller is necessary in order to avoid the corresponding resonant susceptible area of the tower structure (soft–stiff tower design). [ABSTRACT FROM AUTHOR]

Sun-tracking system (STS) is a key factor for solar photovoltaic (PV) future and new answers for the solar market. It will expand large-scale PV projects (PV farms) worldwide, and it is possible to collect more energy from the sun. PV farms consist of thousands of STS that are subject to dynamic loads (wind, snow, etc.), vibrations, and gravitational loads. This paper presents the structural dynamic analysis of a 24 m² bi-axial STS (azimuth-elevation) at different elevation angles based on its modal parameters (natural frequencies, modal shapes, and modal damping ratios) and dynamic performance indices (modal participation factors (MPF), forcing frequencies, and mechanical quality factors) by means of the finite element analysis (FEA). The simulation results show that the structural dynamic design of the STS meets the desired structural requirements and agrees well with structural dynamic standards (EN 1991-1-4 and ASHRAE). These results can be used for further analysis on optimal design and vibration safety verification for the bi-axial STS (PV applications). [ABSTRACT FROM AUTHOR]