College of Automation Xi'an University of Technology, China.
College of Automation Xi'an University of Technology, China.
ISA Trans. 2019 Sep;92:118-133. doi: 10.1016/j.isatra.2019.02.006. Epub 2019 Feb 25.
Torsional vibration of flexible drive chain is a historical issue. With the maximization development and the rotating machinery high-speed operation, the drive chain systems of large-scaled units become more and more complex, which makes the torsional vibration problems becoming increasingly prominent in recent years. This article deeply analyzed the small signal stability of large-scaled WECS based on CMT, elaborated the torsional vibration mechanism and reasons for the first time and pointed out torsional vibration is caused by the disturbance wind and the DPC strategy. The disturbance wind is an external stimulus and can produce a low-frequency torsional vibration at the same frequency as wind speed. The DPC could weaken the drive chain damping. If the total damping of drive chain is negative, the unstable torsion vibration will occur. And if the drive chain is still a under-damped dynamic, the high-frequency torsional vibration at natural frequency will be generated. Therefore, large-scaled WECS must have damping control. This study found that appropriate enhancing drive chain stiffness could reduce low-frequency torsional vibration caused by wind speed. Therefore, a damping and stiffness compensation control method was proposed to suppress the torsional vibration. Compared with the conventional damping control, the new method not only can suppress the high-frequency torsional vibration but also has a good restraining effect on the low-frequency torsional vibration. Furthermore, the detailed design procedures including the calculation of injection damping and stiffness were given in this paper. Finally, the correctness and effectiveness of our analysis were further verified by the simulation experiments.
挠性传动链的扭转振动是一个历史问题。随着大型机组的发展和旋转机械的高速运行，传动链系统变得越来越复杂，近年来扭转振动问题日益突出。本文基于 CMT 对大型 WECS 的小信号稳定性进行了深入分析，首次详细阐述了扭转振动的机理和原因，指出扭转振动是由扰风以及 DPC 策略引起的。扰风是一种外部激励，可在与风速相同的频率下产生低频扭转振动。DPC 会削弱传动链的阻尼。如果传动链的总阻尼为负，则会发生不稳定的扭转振动。如果传动链仍然是欠阻尼动力系统，则会在固有频率下产生高频扭转振动。因此，大型 WECS 必须具有阻尼控制。本研究发现，适当增加传动链的刚度可以减小由风速引起的低频扭转振动。因此，提出了一种阻尼和刚度补偿控制方法来抑制扭转振动。与传统的阻尼控制相比，新方法不仅可以抑制高频扭转振动，而且对低频扭转振动也有很好的抑制效果。此外，本文还给出了详细的设计步骤，包括注入阻尼和刚度的计算。最后，通过仿真实验进一步验证了我们分析的正确性和有效性。
