Papers by Author: Li Xiang Sun

Abstract: Based on the Palmgren-Miner linear cumulative fatigue damage theory, the blade root fatigue loads in different effective turbulence intensities were calculated and analysed. The results show that when the air density and the wind speed are constant, the blade root fatigue loads increase linearly with the effective turbulence intensity increasing, and the slopes increase linearly with the wind speed increasing. According to these results, the main source of the blade root fatigue loads under different wind conditions can be estimated to provide a theoretical basis for WTGS type selection in the special sites.

Abstract: Mode analysis for wind turbine is more and more important with the large-scale direction development of wind turbines. Considering twist angle of blade, centrifugal force, weight of blade, weight of tower and nacelle, turbine inertia, traditional transfer matrix theory is amended and applied in the mode analysis of wind turbine in this paper. Applying amended transfer matrix theory, the mode analysis of a real wind turbine is made and the analysis results are compared with the calculation results from NREL Mode program. The comparison results show that amended transfer matrix theory takes wind turbine inertia into account and have higher accuracy.

Abstract: With the large-scale direction development of wind turbine, the vibrations of wind turbines, which are rigid-flexible coupled multi-body systems, can be easily excited. Control system can be improved to reduce the vibration amplitude and load levels. Fluctuation-suppression pitch control strategy has been improved in this paper. The reference input rotation speed, which is normally constant, is required to change with rotation acceleration in pitch control in this new control strategy. Theory and simulation show that Fluctuation-suppression pitch control (FSPC) strategy can improve the vibration characters of wind turbine and suppress rotation speed and power fluctuation, and it is also quite effective for gust situation