| The problem of pantograph and catenary in railway operation has always been a major problem that troubles railways.Taking the pantograph and catenary offline can damage the stability of the pantograph and catenary system operation.This project mainly analyzes the current status of railway pantograph and catenary,and completes the main six aspects of work:(1)The mathematical theory module of the arc,the physical mathematical model of the arc,and the magnetic fluid dynamics(MHD)equation of the arc were derived.After reserving the knowledge of the arc theory,the COMSOL simulation of the bow net arc was completed,and the relationship between the electromagnetic radiation of the bow net arc and the arc current,energy size,and distribution was obtained.This facilitates the verification of experimental results and data analysis in the future.(2)Completed the construction of the experimental platform for arcing of the pantograph and catenary,and designed the FPGA hardware and software modules for the electromagnetic radiation detection system of the pantograph and catenary,including the design of peripheral circuits with FPGA as the core;Complete the design of analog and digital A/D conversion circuits;Designed a data cache circuit with SDRAM and asynchronous FIFO as the core,solving the storage difficulty problem of data reading and writing with different frequencies;Finally,a USB data communication circuit was designed to complete the work of data transmission to the upper computer.And complete the control and functional implementation of various hardware in software.(3)Due to noise issues in the detection of electromagnetic radiation signals and current signals from pantograph and catenary arcs,which interfere with experimental collection results and subsequent analysis,it is necessary to perform waveform data denoising.In terms of data denoising,it is necessary to select the threshold and threshold function for threshold denoising,compare SNR and MSE under different thresholds,and compare the waveforms of hard threshold denoising and soft threshold denoising.Finally,an improved hard threshold denoising method was selected,The frequency domain analysis compared the FFT’s base 2 and base 4 algorithms,and ultimately selected FFT’s base 4 as the frequency domain analysis algorithm after comparative analysis.(4)Through the Control variates,the arcing situation of pantograph catenary under different distance between pantograph and catenary is tested.The test is carried out by changing the detection distance of the detection system,and the influence of different detection distance on the acquisition signal is analyzed;And the arc electromagnetic radiation and arc current signals were collected using FPGA,and the FFT based 4frequency domain analysis of FPGA was designed.(5)Transfer the data collected by FPGA to MATLAB,and perform signal denoising,time-domain,and frequency-domain analysis on the collected signals in MATLAB software to obtain the time-domain and frequency-domain characteristics of electromagnetic radiation and arc current of the pantograph network arc.By fitting a large amount of experimental data,the relationship curves between the electromagnetic radiation and arc current of different pantograph-catenary distances in the time domain were obtained.It was found that the amplitude of the arcing electromagnetic radiation signal of the pantograph-catenary increases with the increase of the pantographcatenary distance,and the change rate of the arc current and the electromagnetic radiation signal are the same,but the waveform direction is opposite;Through experimental analysis,it was found that as the detection distance of the detection system increased,the arc signal gradually weakened.Therefore,the most suitable detection distance was selected.(6)The GUI interface display part of MATLAB has been designed to achieve interface control that integrates arc signal acquisition,storage,and processing analysis functions. |
PDF Full Text Request