Comprehensive characterization of the periodic attractors problem in the wind turbine control system

In this paper we comprehensively describe and characterize the continuous undesired oscillatory phenomenon existent in the wind turbine control system, even with control enforcement/limits imposed by industry. First, we re-introduce our state-of-the-art validated model for the wind turbine control system and its operational regions based on different wind speeds. Second, we generalize our rigorous proof of the existence of attractors given the control limits provided by industry. Then, we show by simulations that a Hopf bifurcation is existent in the dynamics, which results in undesired continuous oscillations (attractors) to take place when there are drops in certain parameters from the power grid. This phenomenon is shown to be unstoppable even when the control limiters of industry are imposed. This could be explaining some of the problems currently facing the wind turbine controls, especially, in extreme and sudden situations. The results of this paper fully describe the problematic aforementioned phenomenon and reveal what have been observed in field about wind turbine behaviors in certain situations.