NONLINEAR DYNAMICS OF ELECTROMECHANICAL COUPLING IN ELECTRIC TRANSMISSIONS

The shift from internal combustion engines to electric motors requires a deep understanding of the dynamic behavior of electric drivetrains. A key aspect is the electromechanical coupling between the motor and the transmission, where electromagnetic forces interact with mechanical vibrations. This bidirectional coupling influences system performance, comfort, and durability. Electromagnetic torque ripple, caused by magnetomotive forces and flux harmonics, and mechanical effects like gear mesh stiffness variations and transmission errors, contribute to complex vibration behaviors. This study develops a nonlinear dynamic model of an electric drive gear system that integrates motor electromagnetic excitations and gearbox mechanical dynamics. Key nonlinearities such as torque ripple, backside contact, and mesh stiffness variations are included. A nonlinear finite element method improves the accuracy of static gear stiffness evaluation. Numerical solutions of the governing equations analyze the system’s response under different operating conditions. Results show that time current harmonics and spatial magnetic field harmonics significantly affect the frequency content of the electromagnetic torque. Electromechanical coupling intensifies vibrations under steady-state conditions. Ignoring these interactions can lead to inaccurate predictions. This work highlights the need to consider both electromagnetic and mechanical dynamics for accurate modeling, improved performance, and enhanced reliability of electric drivetrain systems.