Investigation On Vibration And Noise Control Of Railway Vehicle’s Critical Equipment Using Multi-Field Source Coupling Analytical Method

With the progress of society and economic development,the rail transit equipment technology grows fast as well,so,"safe,comfortable,green,environmental protection"concept of rail transit deeply roots in people’s heart and people’s requirement of comfort on railway vehicle becomes higher and higher,as a consequence,the vibration and noise problems of railway vehicle causes high attention,gradually becoming a hot research aspect in current academia and engineering.Auxiliary converter is one of the key equipment of metro vehicle,and there are many excitation sources in it,such as transformer,reactor and centrifugal fan,which are the main vibration and noise source in vehicle operation.It has important theoretical significance and engineering application value to study the mechanism,characteristics and optimal control methods of vibration noise during its operation.In this paper,the traditional single factor optimization control method of the vibration noise has been broken through,systematically putting forward the method to predict the vibration noise,design and optimization control methods for the current transformer,whose electromagnetism,structure and fluid field coupling system is complex.Research results is of great significance on the building and control optimization of such complex multi field coupling vibration noise and theoretical system,the main research results and innovation are as follows:The multi-physics field simulation model to investigate the electromagnetic-vibration-noise performance of transformer,which is one of the main vibration sources of auxiliary converter,is established.A method of modifying the parameters of simulation model using transformer modal test and vibration test is proposed.The validity of simulation modeling and analysis method is verified by experiment.Based on the research of the influences of current harmonic asymmetry,core flux density,clamp stiffness,winding stiffness and damping on the vibration of the transformer body and the radiated noise of the structure,specific methods for reducing transformer vibration and noise are proposed in various aspects such as reducing the high-order magnetostrictive force,displacement amplitude and resonance peak value.The simulation analysis process of the aerodynamic noise of the auxiliary converter centrifugal fan and the air duct is established,and the validity of the simulation modeling and analysis method is verified by experiment.Simulations for calculating the vortex distribution of the fan region and the sound pressure level distribution of the internal and external cabinet are performed,and the internal relation between the flow field and the noise propagation is revealed.A conclusion is drawn that the inhomogeneous inlet velocity and the excessive eddy current are the reasons for the excessive noise of the fan.An investigation to find out the influence of increasing blade number,setting up rectifier net and resonant cavity on the uniformity of inlet velocity and the distribution of vortex is carried out.On this basis,a comprehensive optimization design method for reducing the aerodynamic noise of the converter is proposed.A multi-dimensional vibration noise evaluation and optimization system for complex electromagnetic-structure-fluid multi-field coupled systems such as converters is constructed.For the problem of too large electromagnetic vibration transmission of converter,a method for calculating the vibration transmission of complex elastic system which can fully integrate the simulation and test data is proposed as well as the corresponding design method of vibration reduction based on the vibration isolation parameters of transformer and the parameter optimization of cabinet structure.For the problem of the converter cabinet noise optimization,a simulation method to predict noise of the converter cabinet based on statistical energy analysis is presented,and an adaptive method of the converter cabinet noise optimization based on increasing acoustic transmission loss is put forward as well.Focused on the related problems of ventilation,structure light weight and structural fatigue life which affect the vibration and noise performance of converter,a fast calculation flow of transient temperature rise in the inverter module based on the model reduction method is proposed,predicting the transient temperature change curve under different working conditions,which provides the theoretical basis for evaluating the wind volume and the thermal design of the IGBT module.The structural fatigue simulation process based on vibration test load spectrum of actual running line is developed,and the difference of the random vibration test standard is analyzed.The effect of the measured vibration data on the structure fatigue of converter cabinet is revealed,which has important practical value in engineering.