Dynamic Analysis of Wind Turbine Gearbox Components

Mingming Zhao,Jinchen Ji

doi:10.3390/en9020110

Abstract

This paper studies the dynamic response of a wind turbine gearbox under different excitation conditions. The proposed 4 degree-of-freedom (DOF) dynamic model takes into account the key factors such as the time-varying mesh stiffness, bearing stiffness, damping, static transmission error and gear backlash. Both the external excitation due to wind and the internal excitation due to the static transmission error are included to represent the gearbox excitation conditions. With the help of the time history and frequency spectrum, the dynamic responses of wind turbine gearbox components are investigated by using the numerical integration method. This paper explains under which conditions the fretting corrosion, as one of the wind turbine gearbox failure modes, may occur. Furthermore, it is observed that the external excitation fluctuation has large influence on the dynamic responses of both the gears and bearings.

Highlights

The wind turbine drivetrain converts high torque on the main shaft to low torque on the high-speed shaft to meet the electromechanical requirements of the generator
The analysis focuses on the effects of the excitation conditions on gears and bearings of the wind turbine gearbox with the help of the time histories and FFT spectrums
The present work developed a 4-DOF dynamic model of a wind turbine gearbox, which takes into account both the low-frequency external excitation and the high-frequency internal excitation

Summary

Introduction

The wind turbine drivetrain converts high torque on the main shaft to low torque on the high-speed shaft to meet the electromechanical requirements of the generator. Vibrations in wind turbine gearboxes have received significant attention from both the industry and researchers, to the authors’ best knowledge the fundamental failure mechanisms have not yet been fully understood due to the complexity of its nature,. In the context of vibrations, a wind turbine gearbox can be considered as a complex dynamic system subjected to highly complex loading conditions. The torque applied on the gearbox is driven by the rotor blades under fluctuating wind, and the variable loads inherently exist within the entire gearbox. Under such conditions, the fatigue life of wind turbine gearboxes is significantly affected [2]

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