Dynamics Analysis of Planetary Gear Trains in a Wind Turbine Under Mean Wind Speed

Targeting at planetary gear trains (PGTs) used in wind turbines, this paper investigates their vibration and dynamics under the aerodynamic torque of mean wind speed. Wind shear and tower shadow effects are considered in modeling the torque. A lumped parameter model is then developed to calculate the vibration and dynamics response of the PGT to the aerodynamic torque. In this model, the gear teeth and bearings are modeled as springs and the rotation of the carrier and the planet gears as well as the translation of the sun gear are taken into account. The time varying effect of the stiffness of gear mesh is incorporated into the model. Newmark algorithm is used to solve the vibration model established. In the last, the vibration response and dynamic meshing forces of the PGT are simulated and analyzed for rotors with 2 blades and 3 blades. The simulation result demonstrates that the aerodynamic torque is not a constant even under a constant wind speed. Instead, it changes with a frequency which equals the fundamental rotor frequency multiplied by the number of blades. The torque fluctuation causes corresponding vibration response and dynamic force fluctuation in the PGT.