| The speed increasing gearbox is the key component of the wind turbine, whichmust has higher reliability and service life than the general mechanicalsystem because of working in the circumstances of random wind field and high altitudesetting up. The planetary gear transmission system is commonly used in the MW-levelwind turbines, and has the obvious characteristics of low speed, heavy load, varyingspeed and varying load, the dynamic characteristics are very complex due to thefrequent disturbance under the random wind and have a greater impact on reliability andstability of wind turbines. Researching the dynamic properties of planetary geartransmission of wind turbine can be advantageous to break through the key technologyof wind power energy equipment and promote the localization of manufacturing anddesign of wind turbine transmission equipment.This topic is the important component of the National Natural Science Funds(50975294). The dynamics characteristics of the planetary gear transmission system ofwind turbine are studied in the paper, and the main research contents as follows.①Study on external load characteristics of wind turbine transmissionThe AR wind speed model is build on the basis of random signal spectrumestimation method and the spectrum characteristics, and the pneumatic load calculationmodel is build using the wind turbine pneumatic theory. According to the active powerbalance, the Doubly Fed Induction Generator vector control model is build，the electromagnetism torque expression and the Energy conversion relationship ofconstant frequency variable speed motor are deduced based on the matrix analysismethod of rotating electrical machines. The equivalent dynamics model is set upaccording to the mechanical system dynamics. Based on the above, considering thepitch angle control method of wind turbine blade, the wind-mechanical-electrical unitedsimulation model is build and the calculation for the simulation model is carried out, theexternal dynamic load of is obtained and its rule and properties are analyzed.②Dynamics model and dynamic excitation of planetary gear transmissionConsidering the bearing’s flexibility and making the gear pair as spring in meshingline, the torsion-translation dynamics model of planetary gear transmission system isbuild using the lumped parameter method and the differential equations of system arederived based on the mechanical vibration theory and many factors are analyzed such as mesh stiffness, bearing stiffness, planetary gear mesh phase, internal and externalincentive.③Research on the natural vibration characteristics of the planetary gear systemwith time-varying stiffness of gear and bearingThe influences of gear mesh stiffness and bearing supporting stiffness on systemnatural frequency and the modal transition phenomenon are analyzed based oncalculating the natural frequency and vibration modes. The gear mesh stiffness isexpressed by Fourier series, the bearing stiffness expression is build by Hertz contacttheory, and the mesh phasing is considered, the tine-varying rules are analyzed ofsystem stiffness of planetary gear system，the frequency features and the vibrationcharacteristics are researched in the condition of time-varying.④Research on the varying load excitation mechanism and the dynamic responsecharacteristic of wind turbine planetary gear system.Aiming at the speed variation and elastic deformation caused by varying load forplanetary gear system, the transformational relation between the kinetic energy and thepotential energy in varying load conditions are analyzed by energy method, thevibration differential equations of planetary gear system are derived based on theLagrange function and the results part②, the varying load excitation mechanism arediscussed and the influence of load excitation on vibration frequency of system isanalyzed. Taking into account the time-varying characteristicsthe of system stiffness andthe varying load excitation, the dynamic responses are solved by the Newmark methodand the dynamic responses characteristics are obtained.⑤Experimental study of the vibration response characteristics of wind turbineplanetary gear system.The test rig of back-to-back energy feedback was setup and the dynamics propertytesting program of wind turbine was established. The vibration signal of transmissionsystem was measured under the working conditions of steady and unsteady drive/loadtorque. The influence regulations of varying load on the system vibration response wereobtained, the theory model and the research methods were validated by comparing tworesults of steady and unsteady working conditions. |
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