Structural And Dynamics Analysis On The Yaw System Of MW Grade Wind Turbine

As an important part of horizontal axis wind turbine, Yaw system’s main role is tocooperate with control system, which makes the wind wheel always being upwind stateto improve the efficiency of wind turbine power generation. Meanwhile, it also provideslocking torque necessary to ensure the safe operation of wind turbine and shutdownstate.In order to study the dynamic characteristics of wind turbine in yaw and thesecurity and reliability of yaw system, by using the multi-body dynamics method in thispaper, the dynamic characteristics of wind turbine in yaw was analyzed and also thestructure strength of yaw system was calculated, which validated security and reliabilityof yaw system. The method used in this research provided technical reference for designand checking of the wind turbine yaw system with engineering value.The main research included following work:①This paper studied on the aerodynamic theory of wind turbine under steady yaw,yaw amendment was carried out based on traditional BEM theory, derived a BEMtheory suitable for steady yaw as well as criterion generally applicable in yaw powerassessment. Further illustrated the basic structure and function of active yaw system oflarge-scale wind turbine.②According to the German Society of Germanisher Lloyd (GL) certification,topological graph of the wind turbine and the yaw system was drawn. On the basis oftopological graph, wind turbine dynamics model was built in SIMPACK. In accordancewith automatic yaw control principle, automatic yaw control model was established.With the IEC specification, wind simulation model was constructed to realize wholemachine co-simulation in yaw conditions of air-flexibility-control.③Time domain and frequency domain in two kinds of different wind condition ofwind turbine was analyzed. Time domain analyzed the yaw system of wind, pitch anglechanges, power curve and yaw gear meshing. Campbell diagram and the correspondingenergy distribution were found through frequency domain analysis which determinesthe dangerous point of resonance yaw process. The motion equations about torsionalvibration of the tower during yawing was set up, and yawing instability factor wasconcerned to get the conclusion that torsional instability of the tower would not occurduring yawing. ④According to load characteristics of the yaw system of wind turbine, The yawbearing roller simulate with contact gap elements. According to the VDI2230, the highstrength bolt pretension deviation structure is calculated and the finite element model ofthe yaw system with the static strength analysis was constructed. Combined with thefinite element method, the random fatigue load spectrum of high strength bolt wasobtained. According to the GL specification, the notch coefficient parameters of S-Ncurve and bolt was calculated. Based on the linear Miner criterion, the yaw bearing bolteventually damage value calculate was calculated.