Study On Eccentric Vibration Characteristics Of Traction Motor In Subway Power System

As a widely used power source in the field of rail transportation,the vibration control of traction motor power transmission system has been a hot research topic.When the rail vehicle is in normal operation,the motor is excited by the track making the rotor of the traction motor eccentric.The rotor eccentricity will cause the magnetic field change and unbalanced magnetic pull,which will in turn pull the motor rotor eccentricity and intensify the vibration,and transmit and affect the other components of the bogie.This thesis focuses on the effect of motor vibration on other components of the bogie under the consideration of the two-way coupling effect of electromagnetic force and bogie dynamics system and the stable eccentric conditions after coupling.The main contents are as follows.First,a vehicle-track coupling dynamics model based on the multi-body dynamics method is established,and on this basis,the effects of different track classes,different speeds and different loads on the eccentricity of the traction motor are investigated.The results show that the changes of vehicle speed and track class have a more obvious effect on the eccentric distance of the motor,while the changes of pure load hardly affect the eccentric distance.Next,the calculation and analysis of the electromagnetic performance of the traction motor under different eccentric conditions were carried out.The two-dimensional finite element model of the traction motor is established and verified by the finite element method,and the electromagnetic performance and unbalanced magnetic pull of the traction motor under different eccentric conditions are simulated and analyzed on the basis of the previous thesis.The results show that with the increase of vehicle running speed or the decrease of track level,the eccentricity distance and the unbalanced magnetic pull force on the stator and rotor increase;after the occurrence of static eccentricity,the stator and rotor are mainly subjected to the unbalanced magnetic pull with zero frequency in the vertical direction,except that no new frequency component is added.Then,the two-way coupling analysis of electromagnetic force and bogie system is carried out,and the air gap magnetic field,electromagnetic force wave and spatial and temporal distribution of the traction motor are calculated under stable eccentric conditions.The results show that the eccentric distance gradually stabilizes after 3-4 iterations and increases about50 % compared with the initial eccentric distance;the harmonics of the same frequency appear in the neighboring orders of the traction motor electromagnetic force wave under the stable eccentric condition,and the closer to the main wave,the larger the amplitude of the harmonics.Finally,the vibration test experimental analysis and simulation study were conducted.Vibration test experiments are conducted on the power car of the subway train to investigate the vibration characteristics of the eccentric fault motor and the non-eccentric fault motor under the field operation conditions and the influence on the surrounding main components,and simulations such as harmonic response analysis,modal analysis and vibration transmission analysis are conducted based on the model established in the previous thesis to further explain and investigate the experimental phenomena and conclusions.The results show that: the main components of vibration of different eccentric fault motors are basically the same in frequency but different in amplitude,and the vibration of the motor will be transmitted to other parts of the bogie;the analysis finds that the modal state of the motor overlaps with the electromagnetic force wave,which will lead to increased vibration,and this frequency is also the main frequency of the vibration experimental measurement data.