Study on the Dynamic Characteristics of Planetary Gear System Considering Motor Torque Ripple and Suppression Strategy

To address the output torque ripple caused by nonlinear disturbance factors during the operation of a permanent magnet synchronous motor (PMSM), which leads to reduced transmission accuracy and increased noise in the planetary gear system, this study investigates internal excitations such as time-varying mesh stiffness (TVMS) and gear backlash in the gear transmission system and develops a translational–torsional dynamic model using the lumped parameter method. Based on a refined model of the PMSM, the motor torque ripple is calculated and analyzed. Harmonic voltage injection is employed to suppress the ripple, with the torque before and after suppression used as the variable load input for the planetary gear system. The dynamic responses of the planetary system, both before and after the suppression of torque ripple, are computed. The results indicate that the stator current frequency of the motor and the gear meshing frequency exhibit significant modulation effects in the low-frequency range. By comparing the dynamic responses of the gear system before and after torque ripple suppression, it is shown that the suppression strategy effectively improves the time-domain waveforms of the gear system’s vibration signals, bringing them closer to the response under constant torque. It is concluded that the sidebands generated in the low-frequency range are the key factors influencing system vibration, thereby revealing the vibration coupling mechanism between the gear and motor system. This research provides theoretical support for the optimization design and vibration–noise reduction of planetary gear transmission systems.