| With the increase in the size and lighter of the wind turbines, its components become more flexible and natural frequency of the system reduce gradually. The longtime vibration of the components due to the load, will lead to fatigue destroy, so it becomes more important to avoid the damage from the gust and secure their safe when operating in the harsh natural enviroment.Firstly based on the known parameters of the2MW wind turbine power models, simulation, and compared with the Bladed software models of wind turbine power to prove the accuracy of the models built. There is a wide variety loads of wind turbine which is extremely complex and its obviously more seriously for aerodynamic loads. According to the blade element and momentum theory of aerodynamic principle, a wind turbine blade mechanism modeling was made to calculate a single blade element load and then quadrature for the whole blade load. At last, analysis of the relationship between certain parameters and load. Considering the variability of wind speed and the nonlinear load curve, this paper made the wind speed into several partitions, then calculated and analyzed the load variable situation and designed one PID controller for each partitions. When the wind speed changed, the outputs of multiple PID controllers switched according to the management strategy. The simulation results show that the multiple PID switch strategy on load control give a optimal load curve. Compared to single PID control, the new control strategy has better control performance.Though it is not complicated to calculate the load of wind turbines through a dedicated wind turbine sofeware. A mega-watt class load model was independently established in detail, so it could make a good understanding of the relationship between each parameter and load and also have a great significance for the load optimization and control. |
