Research On The Improvement Of The Operating Control Strategies Of The Variable Speed Variable Pith Wind Turbine

On the basis of the basic control strategies analysis of the variable speed variablepith (VSVP) wind turbine, aiming at solving the common problems of the wind turbine,such as the rotor overspeed, overload of the key components in the gust wind conditions;the rotor can not maintain the optimal tip speed ratio in the optimal control zone; towerfore-aft vibration and drive train torsional vibration. This article investigated thecorresponding improved control methods.Main researches covered in this paper are as follows:Chapter1: Introduction. This chapter introduced the background of the researchtopic and state-of-art of the wind power generation technology and development trends.Chapter2: Establishment of the wind turbine model. The whole wind turbinemodel was established based on the GH Bladed (horizontal axis wind turbine design andload calculation software). This is the basis of the following simulation and validationof the control algorithms.Chapter3: The operating control principle of the VSVP wind turbine. The basic operatingcontrol strategy of the VSVP wind turbine was analyzed, including the torque control,pitch control and the switch between different control zones.Chapter4: Gust wind control strategy. Wind turbine usually can not make quick response inthe gust wind, and it leads to the over-speed of the rotor, too large loads, even the shutdown of thewind turbine. This paper optimizes the transition between different control zones to achieve the aimof the gust wind suppression based on the basic operating control strategy.Chapter5: Maximum power point tracking control. The operating characteristic of thewind turbine in the optional control zone was analyzed. Due to the large moment of inertia of thewind turbine drive train, the rotor can not maintain the optional tip speed ratio well. Method of howto convert the wind power to electricity mostly in low wind speed was investigated. And the controlmethod was validated by full and half gust wind.Chapter6: Active vibration control of the key components. The own damping of the windturbines is very small, and it is very common that the tower vibration and drive train torsionalvibration happen. Those decrease the lifespan of the wind turbine. This article applied the sky-hookdamping algorithm to control of the tower fore-aft vibration, and the drive train torsional vibrationwas also suppressed by the way of additional torque. The simulation results showed that the controlmethods could decrease the load of the tower and gearbox obviously.