An improved decoupling method for dynamic modeling of wind turbine gearbox with planet gear journal bearings

Planet gear journal bearing (PGJB) is usually modeled by nonlinear film force or linear stiffness-damping coefficient in the dynamic modeling of wind turbine gearbox (WTG) with PGJB. The former has high simulation accuracy but a high computational cost; the latter has high computational efficiency but neglects time-varying film force and journal-sleeve eccentricity, leading to limited simulation accuracy. In this study, an improved dynamic modeling approach of PGJB is proposed considering the time-varying journal-sleeve eccentricity and additional eccentricity correction force based on the linear stiffness-damping coefficient. A rigid-flexible coupling dynamic model of WTG with PGJB is established, considering the structural flexibility of gearbox housing, carrier, ring gear, and shafts, as well as the dynamic supporting forces of PGJB. The influences of operating conditions and PGJB’s parameters on calculation accuracy and dynamic characteristics of WTG are studied and partially verified by an initial experiment. The results show that the dynamic meshing force fluctuation makes PGJB’s stiffness-damping coefficient and additional eccentricity correction force change periodically. The proposed model accurately predicts system response within boundary conditions, especially a prediction error of 10% in planet gear vibration displacements at the rated operating condition. Decreasing the width-to-diameter ratio and radial clearance of PGJB and increasing input torque improve the load-sharing performance of WTG.