Search

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]

Currently, both the permanent magnet synchronous generators and the electrically excited synchronous generator are used in the direct-drive wind turbine technology to produce electrical energy. Aiming at the high cost of permanent magnets, the commercial availability, mainly in African, and the difficulty of the magnetic field weakening operation of the PMSG machine, the work studied a novel design of a direct-drive H-Darrieus wind turbine (H-DWT) based on doubly fed induction generator (DFIG) using MATLAB/Simulink software. The stator topology is connected directly to the grid while the rotor is connected to grid with back to back converters. The study includes the sizing, modeling, and control of the proposed system. A sliding mode control (SMC) approach is selected in order to achieve robust control of active/reactive power injected into the grid. The real wind speed spanning a period of one year of the province of Adrar city located in the south of Algeria is used to test the complete system. The simulation results illustrate the operating efficiency of a DFIG and the performance of the SMC method in stator powers tracking in direct-drive wind energy conversion systems. • The design of the direct-drive vertical axis wind turbine system is realized through a well detailed dimensioning. • A detailed modeling of DFIG under fewer hypotheses is introduced. • Sliding-mode control approach is designed for Stator power regulation of DFIG. • The proposed SMC presented the best performance. [ABSTRACT FROM AUTHOR]