Ma L.,Beihang University |
Chen J.,Beihang University |
Du G.,Beihang University |
Cao R.,Guangdong Mingyang Wind Power Industry Group Co.
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2010
This influence of trailing edge's thickness on aerodynamic performance for large wind turbine airfoils was studied. The trailing edge's thickness of NREL wind turbine airfoils S814 and S827 with test data was numerically treated with XFOIL. The trailing edge's thickness changes between 0.5% and 5.0% relative to chord with constant maximum thickness, camber and chord. The results indicate that when trailing edge's thickness increases within certain range, lift coefficient and drag coefficient also increase, but lift-drag ratio increases and then decreases. Lift coefficient and lift-drag ratio of airfoils reach to the best conditions when trailing edge's thickness is around 1.5% relative to chord. The conclusion can be used to design the wind turbine blades.
Song X.,Beihing University |
Chen J.,Beihing University |
Du G.,Beihing University |
Cao R.,Guangdong Mingyang Wind Power Industry Group Co
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2014
With the aim of accurately taking into account viscous effects and profound influence of vortex sheet downstream on the aerodynamic performance of wind turbine blades, a model combing blade aerodynamic model based on the classic lifting-line theory with full free vortex wake model was presented, The numerical solution was insured to be fast and stable by parallel processing, fast multipole method (FMM) and predictor-corrector-relaxation scheme. The validity of present method were performed through comparisons with the National Renewable Energy Laboratory (NREL) experimental data and CFD results from the references, under axis flow and yaw condition, respectively.
Song X.-C.,Beihang University |
Chen J.,Beihang University |
Chen L.,Beihang University |
Du G.,Beihang University |
Cao R.-J.,Guangdong Mingyang Wind Power Industry Group Company Ltd
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2013
Through optimization of the blade bound circulation distribution, a fast aerodynamic optimization method for blade of wind turbine was developed. In the method, the full free vortex wake model was introduced, and then computed quickly by parallel processing and fast multipole method(FMM). When selecting Fourier series representation of the bound circulation as the optimization variables to decrease the number of optimization variables, using the power coefficient as an objective function and adding the thrust coefficient as a constraint, optimization was carried out and optimal blade geometry parameters were obtained from optimal circulation distribution. This was validated through comparisons with the National Renewable Energy Laboratory (NREL) experimental rotor. Results show that, when tip speed ratio was 3.79 and 4.74, with a thrust coefficient constraint, optimization could enhance the power coefficient by 32% and 8%, respectively. When a variety of blade numbers and tip speed ratios were chosen, without a thrust constraint, global optimizations were performed, and the power coefficients are over 0.48.
Li H.,Central South University |
Yang C.-H.,Central South University |
Deng W.-L.,Xiangtan University |
Ma X.-L.,Guangdong MingYang Wind Power Industry Group Co.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010
When doubly-fed induction generator (DIFG) cuts in power grid, it will inevitably have an impact on the power grid. Excessive rush current will shorten the life of the motor, increase power grid voltage fluctuation, and may even cause the failure of the cutting-in grid. In this paper, the matrix converter is regarded as the AC-excitation systems and equalized as a virtual rectifier and virtual inverter. This control system regards the grid voltage and phase as given value, the stator voltage as a feedback value, and simplifies the solution of complex decoupling control. It will make DIFG stator voltage changes with grid voltage simultaneously by the control of voltage and phase of the virtual inverter. Thereby it reduces the impact current of the cutting-in grid. The experimental results show that the impact current of the cutting-in is little, and verify the feasibility of the control. © 2010 Chin.Soc.for Elec.Eng.
Chen C.,Xiangtan University |
Chen C.,South China University of Technology |
Xie Y.,South China University of Technology |
Ma X.,Guangdong MingYang Wind Power Industry Group Co.
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2012
Aim to solve the poor dynamic performance and the low disturbance resistance of PI power decoupling controller for DFIG power generator system based on matrix converter, this paper propose a nonlinear control algorithm for the AC-excitation DFIG system. First, we establish the mathematical model of the DFIG, based on the model, use the inverse system theory and deduce the inverse model, add the inverse model in series to the front of the original system model, develop the whole system to a pseudo linear system. Consider the system performance influenced by the parameters of the linearized model, we use the predictive control to improve the robustness. The simulation results show that the control strategy has fast response and good dynamic performance. The off-grid and cut-grid experimental data validate that under sub-synchronous or super-synchronous state, the stator voltage and frequency can maintain stability and achieve variable speed constant frequency operation.
Yan F.,Tianjin University |
Yan F.,Guang Dong Ming Yang Wind Power Industry Group Ltd Company |
Li Y.,Tianjin University |
Luo Z.,Tianjin University |
And 2 more authors.
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2016
In this paper, the failure behavior of three-sheet 6061 aluminum alloy resistance spot is studied to evaluate the mechanical properties of the welded joint, the tensile-shear tests were performed in six different joint types. Mechanical performance of the joint was described in terms of peak load and energy absorption. The results showed that different joints exhibit different peak load and energy absorption. The rotation of nugget plays an important role in controlling the peak load and energy absorption during the tensile-shear test. Large rotation of nugget will lead to the low peak load and energy absorption. The maximum peak load and energy absorption is obtained when the sheet/sheet interface is subjected to pure shear. © 2016, Editorial Board of Transactions of the China Welding Institution, Magazine Agency Welding. All right reserved.