Research On Lateral-torsional Coupling Vibrations In The Machine-rotor Dynamics Of Electro-mechanical Transmission System

The electromechanical compound transmission system of vehicle is composed of permanent magnet synchronous motor and mechanical transmission parts,and is a typical electromechanical coupling system.The transmission performance of the system is related to the electromagnetic parameters of the motor and the structural parameters.And the variation of the electromagnetic parameter not only affects the transmission performance of the system,but also influences the characteristics of mechanical transmission components.This also provides a foundation for the study of electromechanical coupling.Vibration is one of the most important factors to measure the performance of a large number of transmission systems.Large vibration may lead to the damage of the shaft,the increase of noise and the poor performance of the system.In this paper,the electromechanical coupling mechanism is explored,and the effect of coupling parameters on torsional vibration and lateral vibration of the system is analyzed,and a series of coupled vibration laws are obtained.Main contents include:A preliminary study on the application of permanent magnet synchronous motor in automobile electromechanical energy conversion is conducted.Based on the permanent magnet synchronous motor dynamic model(Park model),according to the load fluctuation,inductance,permanent magnet flux and current controller and other factors,the electromagnetic parameters are obtained by freezing permeability method.Frequency characteristics of electromagnetic torque ripple due to the harmonic current injection and the electric saturation is discussed through the finite element calculation.The mechanism of electromagnetic vibration is revealed.Considering the influence of current injection on the electromagnetic torque of permanent magnet synchronous motor,the torsional vibration model for the permanent magnet synchronous motor and the mechanical rotor is built.The torsional vibration response under external excitation is calculated.The influence of the harmonic current injection on the current frequency charatericstics is analyzed.Then the law of vibration on the electromagnetic parameter and the mechanical parameter is obtained.Finally,the active dampling mechanism of the electromechanical coupling torsional vibration is revealed.According to different pwer factor angle,the unbalanced magnetic pull caused by the rotor eccentricity is stydied.Firstly,the unbalanced magnetic pull model of motor rotor is established.Then nonlinear lateral vibration equation of electromechanical coupled system is built.The nonlinear stability is analyzed.And the forced vibration response is obtained by using L-P method.The electromechanical coupling law under the unbalanced magnetic pull is obtained.Rotor mass eccentricity and load fluctuation have cross coupling between the torsional coupling channel and the transverse motion coupling channel,which can produce multi-electromechanical coupling vibration.This chapter considers the unbalanced magnetic pull and load torque fluctuation of eccentric rotor permanent magneti synchronous motor,the multiple-electromechanical coupling dynamic model is established based on the electromechanical analysis dynamics.The multiple-coupled vibration chanrateristics under the electromagnetic paratmeters is solved by the nonlinear dynamics theory and numerical algorithm.The action of vibration excited by different electromagnetic state is calculated and analyzed.And finally,some vibration reduction methods of electromechanical transmission systems for the main mechanical and electrical parameters is studied and obtained.