Hasil untuk "Railroad engineering and operation"

SI Junmin, YUE Xuelei, TIAN Di et al.

High power density and high efficiency are two important trends in the research of permanent magnet synchronous motors (PMSM) used in metro traction systems. The key to achieving these objectives lies in improving performance in current loop control. However, under control conditions with a low carrier wave ratio, the coupling effect between the <italic>d</italic>-axis and <italic>q</italic>-axis currents intensifies as this ratio decreases. Additionally, digital control delays further amplify this coupling phenomenon. As a result, both the dynamic response speed and the robustness of the current regulator decline. To address these issues, this paper presents the design of an internal model decoupling controller capable of compensating for digital control delays, based on the principle of internal model control (IMC). This controller achieves the precise decoupling of <italic>d</italic>-<italic>q</italic> axis currents, optimizes the dynamic performance of the current regulator, and enhances system robustness. Simulation analyses and experimental verifications conducted on the experimental platform of permanent magnet traction on Xi'an Metro Line 1 demonstrate that, compared to PI current regulators, the designed IMC controller exhibits stronger robustness, faster dynamic response, and reduced torque error, while meeting the design index of 3%.

LI Can, LIU Yunhua, LIU Guowang et al.

The reliability of input inrush current suppression circuits is crucial for ensuring the stable operation of power boards, deemed one of the fundamental requirements for the safe operation of electric locomotives. In order to improve this reliability, this paper proposed a series of optimization measures based on the failure instance involving anti-inrush metal oxide semiconductor field effect transistors (MOSFET) in a power supply application. The initial analysis addressed the waveform timing of MOSFETs using a simplified model, deriving the working principles and related calculation formulas for input inrush current suppression circuits. Subsequently, a loss evaluation method for the MOSFETs’ safe operation area (SOA) was introduced, based on the Miller effect. Through evaluating SOA loss in the measured waveform, the root cause of the anti-inrush MOSFET failure was identified to be the insufficient power derating of the device at elevated temperatures. To address this issue, optimization measures were proposed, such as adjusting the device model according to failure cause, extending the Miller platform time, and implementing a delayed start-up. The results from model simulations were harnessed to calculate energy demands for switching on the anti-inrush MOSFET and energy bearing limits under various input conditions. The calculation results show that the MOSFET power derating after optimization aligned with requirements throughout the entire input voltage and temperature ranges. The subsequent experiments were conducted on an engineering prototype under full conditions. The experimental results demonstrated the efficacy of the proposed optimization measures in effectively enhancing the reliability of input inrush current suppression circuits.

Liang Chen, Liyi Xiong, Fang Zhao et al.

Purpose – The safe operation of the metro power transformer directly relates to the safety and efficiency of the entire metro system. Through voiceprint technology, the sounds emitted by the transformer can be monitored in real-time, thereby achieving real-time monitoring of the transformer’s operational status. However, the environment surrounding power transformers is filled with various interfering sounds that intertwine with both the normal operational voiceprints and faulty voiceprints of the transformer, severely impacting the accuracy and reliability of voiceprint identification. Therefore, effective preprocessing steps are required to identify and separate the sound signals of transformer operation, which is a prerequisite for subsequent analysis. Design/methodology/approach – This paper proposes an Adaptive Threshold Repeating Pattern Extraction Technique (REPET) algorithm to separate and denoise the transformer operation sound signals. By analyzing the Short-Time Fourier Transform (STFT) amplitude spectrum, the algorithm identifies and utilizes the repeating periodic structures within the signal to automatically adjust the threshold, effectively distinguishing and extracting stable background signals from transient foreground events. The REPET algorithm first calculates the autocorrelation matrix of the signal to determine the repeating period, then constructs a repeating segment model. Through comparison with the amplitude spectrum of the original signal, repeating patterns are extracted and a soft time-frequency mask is generated. Findings – After adaptive thresholding processing, the target signal is separated. Experiments conducted on mixed sounds to separate background sounds from foreground sounds using this algorithm and comparing the results with those obtained using the FastICA algorithm demonstrate that the Adaptive Threshold REPET method achieves good separation effects. Originality/value – A REPET method with adaptive threshold is proposed, which adopts the dynamic threshold adjustment mechanism, adaptively calculates the threshold for blind source separation and improves the adaptability and robustness of the algorithm to the statistical characteristics of the signal. It also lays the foundation for transformer fault detection based on acoustic fingerprinting.

Xiaohao CHEN, Weihua MA

In order to study the effect of the time delay on the stability of EMS maglev train and solve the problem of instability of maglev train, a single degree of freedom electromagnetic suspension model based on double loop feedback control system was established. Based on the time delay of controller, the Routh-Hurwitz stability criterion was used to determine the characteristic root distribution of the system. The critical threshold of Hopf bifurcation was provided quantitatively. It was pointed out that when the controller delay was larger than the critical value, the system equilibrium point was no longer stable. A single-degree-of-freedom maglev bench was developed. The correctness of the theoretical analysis was verified by numerical simulation and bench test.

Hailong WANG, Linghui WEI, Canjiang YAO

The strength of the gear pair in the high-speed train gearbox is a key factor for the safe operation of the train, using China’s independent research and development high-speed train bogie gearbox gear as study object, three-dimensional gear system model was established, and finite element model was built by SOLIDWORKS simplifying, and with ANSYS WORKBENCH, static and transient mechanical analysis of gear meshing parts was carried out. Theoretical calculation and simulation results were both within the safe range of strength, and met the designed requirements. In transient dynamics analysis, it was found that there was some higher contact stress and stress fluctuation at the starting stage of the gear, which would have some adverse effects on the reliability of the gear system.

WANG Junran, ZHANG Kunlun, HUANG Qing et al.

In charging control system of trolley bus, the output performance of the control system would be unstable caused by external turbulent, which results in the noise amplified. To enhance the robust and adaptive of control system, a new no-linear control method was proposed based on tracking differentiator to improve the charging control performance of ultra-capacitor trolley bus and optimize the curve of the output current and voltage of the system. Aiming at the problem of control parameter variety, a Ziegler-Nichols method was used to adjust the parameter. Simulation and test results completely proved that the proposed method was effective, which improved performance of the control system apparently, solved the contradiction between rapidity and overshoot, and realized quick and smooth charging for the super-capacitor energy storage trolley bus.

A. V. Paranin, A. B. Batrashov

The article compares the results of calculation of the finite element simulation of current and temperature distribution in the scale model of the DC catenary with the data of laboratory tests. Researches were carried on various versions of the structural design of catenary model, reflecting the topological features of the wire connection, characteristic of the DC contact network. The proportions of the cross-sectional area of the scaled model wires are comparable to each other with the corresponding values for real DC catenary. The article deals with the operating conditions of the catenary model in the modes of transit and current collection. When studying the operation of the scale catenary model in the transit mode, the effect of the structural elements on the current distribution and heating of the wires was obtained. Within the framework of the scale model, theoretical assumptions about the current overload of the supporting cable near the middle anchoring have been confirmed. In the current collection mode, the experimental dependences of the current in the transverse wires of the scale model are obtained from the coordinate of the current collection point. Using the model it was experimentally confirmed that in the section of the contact wire with local wear, not only the temperature rise occurs but also the current redistribution due to the smaller cross section. Thus, the current share in other longitudinal wires of the scale model increases and their temperature rises. Scale and mathematical models are constructed with allowance for laboratory clamps and supporting elements that participate in the removal of heat from the investigated wires. Obtained study results of the scale model allow to draw a conclusion about the adequacy of the mathematical model and its correspondence to the real physical process. These conclusions indicate the possibility of applying mathematical model for calculating real catenary, taking into account the uneven contact wear wire and the armature of the contact network.

CHEN Long, DAI Huanyun, GUO Zhaotuan et al.

The characteristics of the anti-yaw damper for high-speed trains in China were studied by means of the test method, including the analysis of dynamic damping and dynamic stiffness parameters. The experimental results showed that the dynamic stiffness of the anti-yaw damper increased with the increase of the frequency value, while the dynamic damping value decreased. At the same time, the adaptability analysis of the high-speed trains, including the stability, the maximum lateral acceleration of the vehicle body and the derailment coefficient, were calculated by using the dynamic simulation software SIMPACK. The simulation results showed that the anti-yaw damper meanwhile ensures the linear stability and the curve through performance, which verified the superiority and necessity of the anti-yaw damper in the practical application of the high-speed trains.

ZENG Yaping, DING Jie, WANG Yongsheng et al.

Aiming at the phenomenon of abnormal noise about a type of electric locomotive cab, the vibration and noise of related parts were tested. The wheel vibration characteristics, carbody vibration transmission performance, cab structure mode and cavity mode were analyzed, and the possible causes of abnormal noise were obtained, which was pointed out that the low-frequency vibration caused by polygonal misalignment was the main causes for the excessive vibration of cab, the sound and solid coupling vibration between the vibration frequency of the cab panel and cavity mode was the fundamental cause of the abnormal noise of electric locomotive.

L. A. Muginshtein, M. I. Mekhedov

Determination of the actual capacity of rail lines, taking into account technical and technological features of operation of technical stations and running sections is one of the most important systemic problems facing the industry. In order to solve the problem a dynamic mathematical model was developed where the number of receiving-departure tracks in technical station yards, time for holding tracks for handling transit cargo trains, intervals of following trains passing in train flows in up-and-down directions connected by the system of interdependencies. The model allows to reduce train-hours and to increase local speed at the passage of train flows due to optimization of ratios of holding time of receiving-departure tracks, number of such tracks and values of intertrain intervals. By means of dynamic model the reasons of increase in holding time of tracks in up-train yards of the st. Karymskaya at increase in number of receiving-departure tracks are explained. Direction of increasing capacity of up-train yards at st. Karymskaya is the consistent implementation of measures to ensure daily provision of locomotives, serving the Eastern operation area, at the st. Karymskaya in rate of 5 - 10 locomotives and relevant receive of up-train flows from the next road in the amounts determined by real available capacity at the st. Karymskaya, changed after creating a locomotive reserve.

ZHANG Tiancheng, DU Yaoxin, WU Wangqun et al.

JD372 motor of GMC96 rail grinding vehicle was introduced from the design, manufacture, test and operation. Threebearing structure design was used with un-driving end adopted matched pushing bearing for high shock and vibration characteristics of the motor. The motor has excellent performance, and advanced technical and economic indexes which satisfies the high-speed heavy line maintenance performance requirements.

FANG Weng-wu, LIU Wei, LUO Shi-hui et al.

Based on the elastic wheelset, wheel polygonization rigid-flexible coupling vehicle dynamics simulation model was established. Firstly, reasonableness of elastic wheelset was analyzed; then, by modifying command to form polygonal wheel, influence of elastic wheelset polygonization parameters-wave depth, phase angle and harmonic order to vehicle dynamics performance at different running speed was researched, and important indicators of the horizontal force of the axle, the wheel-rail lateral force, derailment coefficient, wheel load reduction rate were given at the speed of 40~80 km/h, which determined the critical speed. Simulation results showed that the three polygonization parameters effected on dynamics performance differently, but all had little impact on the derailment coefficient, and wheel load reduction rate had great impact at the speed of 60 km/h, so long-term operation at 60 km/h should be avoided to prevent resonance.

陈明奎, 谭利红

A method of measurement parameters programmatically configuring based on LabVIEW was introduced. The technique of modifying measurement parameter in human machine interface was discussed in detail, in which many advanced programming techniques, for example, applying VI reference, property node calling, controls references indexing, genetic reference converting to specific reference, were applied. The module of measurement parameters programmatically configuring in measurement system extended the software’s suitable scope and it is beneficial to software’s modularization and reuse.

Leopold Hrabovský

This contribution describes a determination of maximum height of the cap of crosssectional area of the belt conveyor with one-idler set on the basis of known value of useable conveyor belt width. At the same time is determined the biggest crosssectional area of belt conveyor with three-idler set assuming that the values of surcharge angle, conveyor belt width, troughing angle and length dimensions of idlers are known as well.

Michal Dorda, Dušan Teichmann

The paper deals with a two-stage queuing model of the reception sidings and the hump in the marshalling yard Ostrava - Pravé nádraží. We distinguish two types of shunting - primary shunting of arriving trains we consider to be customers and secondary shunting to be system failures. By solving of the presented mathematical model some important characteristic of the modelled system are obtained.

Rudolf Kampf, Daniela Hykšová

This article focuses on waste management and its connection with reverse logistics, case study of waste management in the Pardubice public transport company. Article focuses on suggesting an alternative way of waste processing of polluted diluents. Improving waste processing could gain expenses saving and generate more profit from this area.

Eva Sventeková

V príspevku sú popísané vybrané ukazovatele vyjadrujúce prevádzkové charakteristiky terminálu intermodálnej prepravy. Metodika ich výpočtu je odvodená z podkladov projektovej dokumentácie plánovaných a rekonštruovaných terminálov intermodálnej prepravy. V príspevku je riešený výpočet efektívneho výkonu terminálu, počet manipulácií s kontajnermi, stanovenie dĺžky manipulačných koľají a koľají hlavnej prekládkovej skupiny, analýza využitia úložných plôch terminálu a jeho kapacita.

Marián Sedliak, Marián Šulgan

Článok predstavuje prehľad metód, pomocou ktorých môže výrobný podnik uskutočniť kategorizáciu vstupných materiálových položiek do tried s rozličnou prioritou riadenia ich obstarávania, čo slúži ako podpora pre rozhodovanie o vhodnom spôsobe obstarávania jednotlivých vstupov.

Hana Císařová, Jaromír Široký

Due to the increasing customer demands for quality traffic, increasing transport volumes and diverse range of possible technologies, logistics provides solutions in freight transport. This article focuses on logistics and information technology, market principles and new trends in the City logistics. Currently, it is important to solve the transport service in the City logistics, distribution models which are a guarantee of new opportunities for optimization of transport in urban areas.

Martin Kendra

Skvalitnenie verejnej osobnej dopravy môže prilákať cestujúcich z individuálnej automobilovej dopravy na hromadnú dopravu. Je to jediná cesta ako z hľadiska trvalo udržateľného rozvoja možno zabezpečiť primeranú mobilitu obyvateľstva bez rizika kongescií a iných negatívnych externalít. Železničná spoločnosť Slovensko, a.s. (ZSSK) rozbehla v roku 2005 projekt Nový poriadok, ktorého cieľom je skvalitnenie služieb ZSSK so zameraním hlavne na požiadavky zákazníkov.