Study on the Electromechanical Coupling Torsional Vibration Characteristics of Electric Drive Transmission Systems under Motor Harmonic Excitation

Considering the spatial harmonic and time harmonic excitation of the permanent magnet synchronous motor, and the dynamic meshing excitation of gear pairs, this paper constructs one electromechanical coupling torsional vibration model. The torsional vibration characteristics of the electric drive transmission system in pure electric vehicles are investigated. Key electromechanical parameters are obtained by numerical calculations, and the electromechanical coupling system model is solved using the Runge-Kutta method. Finally, the system dynamic response characteristics at rated speed of 3000 r/min are analyzed. The results indicate that the significant bidirectional coupling exists between the electromagnetic excitation of the motor and the mechanical excitation of the gear transmission system. The current spectrum contains fundamental and harmonic components, along with components of gear meshing frequencies and their modulated sideband characteristics relative to the electrical frequency. The electromagnetic torque spectrum exhibits components of gear meshing frequencies, and gear angular velocity fluctuations are influenced by motor harmonic excitation. Under multi-source excitation, this study reveals the frequency modulation mechanism of torsional vibrations in electromechanical coupling drive systems, providing a theoretical basis for vibration and noise suppression.