| After decades of development, wind power has been internationally recognized as one ofthe most mature technologies, the development of low-cost and the most promising renewableenergy. Many countries consider wind power as an important choice to improve the energystructure and response to climate change. Variable pitch control is one of the key technologiesof wind turbine power control, in-depth study of large variable pitch control technology hasimportant practical significance.Variable pitch wind turbine is the prevalent types in the market. The unit control threeblades of the wind turbine at the same time and set the wind speed at the axis of the rotor bladesas the reference wind speed. However, in practical applications, due to the presence of surfacefriction, the wind speeds at different heights are different. With the continuous increase of thecapacity of the units, the length of the wind turbine blades become bigger and bigger. So, thedifference between actual wind speed and reference wind speed become larger. This hasresulted in the large loads on the wind turbine blade and compared to the rated power, outputpower has greater volatility.Firstly, analysis and research have been made about uneven distribution of effective windspeed on large-scale wind turbine. And mathematical model has established based on the theblade azimuth weighting coefficient assigned. Then we designed a fuzzy pitch controller andfuzzy PID pitch controller, then, combined with the previously established mathematicalmodels to simulate and analyze.The results show that, fuzzy controller only barely meet the design requirements in thegeneral case. It is difficult to ensure the safe operation of the unit in harsh environments. Thefuzzy PID controller can adjust the three parameters of the PID online. Thereby adjusting theblade pitch angle in order to achieve the smooth control of the output power of the unit. Thecontroller can better meet the design requirements. |
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