Purpose <p>Electric drive systems involve complex interactions among mechanical, electrical, and magnetic fields, which significantly influence system performance and service life. Existing models often overlook nonlinear factors, limiting their accuracy in predicting dynamic behavior. Therefore, it is essential to establish a high-precision dynamic model to investigate the multi-physics coupled vibration characteristics of electric drive systems.</p> Method <p>This study proposes a multi-field coupling dynamic modeling method for electric drive systems, integrating conformal mapping, equivalent magnetic network, and finite unit method. The model accounts for numerous nonlinear factors, including magnetic saturation effect、magnetic field harmonics、time-varying meshing stiffness and eccentricity errors, and is applicable to both steady-state and transient conditions. The proposed approach enables comprehensive analysis of electromechanical interactions while maintaining computational efficiency compared to conventional models.</p> Results and Conclusions <p>The results show that complex frequency features, such as modulation frequency, exist simultaneously in the spectrum under the multi-field coupling effect, which further exacerbates the electromagnetic and mechanical vibration excitation. The sensitivity of the mechanical response to the meshing errors is consistent with that of the gear speed class. The gear eccentricity error exacerbates the vibration and dynamic load response of the system, with the coexistence of amplitude modulation and frequency modulation, which introduces a rich modulation frequency that can be expressed as |<i>f</i>_<i>mn</i> ± <i>f</i>_<i>rn</i>|, (<i>n</i> = 1, 2). The proposed model effectively captures nonlinear interactions in electric drive systems, providing insights into vibration mechanisms and dynamic load responses.</p>