最新刊期
期 6 ， 2021
- 摘要：In response to the energy saving and consumption reduction requirements of the medium-speed maglev train suspension systems, a permanent magnet electromagnetic hybrid suspension and guidance system was proposed. According to the working principle of this permanent magnet electromagnetic hybrid suspension and guidance system, the structural composition of the permanent magnet electromagnetic hybrid suspension and guidance system was determined, analysis of suspension and levitation force characteristics, self-guide characteristics, and research on the air gap control method and anti-seize control strategy were completed.Based on the establishment of the system mathematical model and simulation model, the system scheme was simulated and veri fied.Suspension & levitation force loss, temperature rise, suspension controller performance of the hybrid suspension electromagnet,and suspension guidance capacity, bearing capacity, etc. of the suspension system in straight and curved sections were tested. The results show that the permanent magnet electromagnetic hybrid suspension and guidance system has the characteristics of strong carrying capacity, low electric current energy consumption, and almost no heat. And the self-adaptive ability of the system meets the requirements of medium-speed maglev operation, which will lay the foundation for the promotion and application of medium-speed maglev trains.关键词：medium speed maglev train;permanent magnet electromagnetic hybrid suspension;guidance system;self-guided characteristic;electromagnet;anti-seize;simulation;finite element
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发布时间：2022-01-18 - 摘要：The abnormality of the suspension system means that the operating state of the suspension system does not match the expected state, and the system has no faults in the actual operation of the middle-low speed maglev train. Accurately detecting the abnormality of the suspension system helps managers allocate limited monitoring resources reasonably, arrange preventive maintenance plans in advance, reduce unplanned maintenance costs, and reduce accident rates. Although an empirical threshold based on the suspension gap can be obtained according to the "Technical Conditions for the Suspension Control System of Middle-low Speed Maglev Trains CJ/T458—2014", it is affected by the non-unique rated suspension gap and external disturbances, which will cause false negatives in engineering applications. Meanwhile, the problem of the balance of suspension gap data increases the dif ficulty of anomaly detection. Therefore, an anomaly detection method for suspension systems based on the Gaussian distribution of hyperspheres was proposed. Firstly, FWHT(Fast Walsh-Hadamard Transform) technology was used to extract sample features, and the feature distribution space was made approxim ate to a hypersphere. Then, the abnormal threshold was determined according to the Euclidean distance between the sample feature and the center of the sphere. The experimental results of the field data show that, compared with the methods based on empirical threshold, the principal component analysis (PCA) and support vector data description (SVDD), the proposed method is more superior in anomaly detection ability.关键词：maglev train;suspension system;suspension gap;anomaly detection;FWHT;PCA;SVDD;track irregularity
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发布时间：2022-01-18 - 摘要：Taking the virtual rail train as the research object, the comprehensive comfort evaluation model was constructed considering the in fluencing factors of its comfort. Through the field investigation and analysis of the importance of the in fluencing factors of passenger comfort, the analytic hierarchy process was used to determine the weight relationship of each factor, the existing indicators and platform test were compared and analyzed to determine the single factor comfort evaluation method, and the comfort evaluation system was established to complete the comprehensive comfort evaluation. Finally, taking Yibin smart rail as an example,the results of questionnaire survey showed that the evaluation method was consistent with passengers' feelings, and according to the evaluation results, suggestions on improving the comfort of virtual rail train were put forward, which provided theoretical reference for the further design and development of virtual rail train.关键词：virtual rail vehicle;comprehensive comfort;evaluation model;urban rail transit
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发布时间：2022-01-18 - 摘要：When the emergency braking of high-speed trains is greater than 300 km/h, wind resistance braking is an effective auxiliary braking measure. In this paper, based on the N-S and k-ε double equation model of the three-dimensional steady incompressible viscous flow field, a preliminary analysis of the aerodynamic performance of the high-speed train with brake wing panels was carried out with the computational fluid dynamics method. Directional force, vertical lift, lateral force, gas flow field aerodynamic interference effect and aerodynamic noise were calculated and explained in detail on the selection of different longitudinal positions, different upwind angles and different sets of longitudinal arrangement of the first row of wind wing panels. Preliminary research shows that: ① When a single-row brake wing panel is installed on the roof of a 350 km/h high-speed train headway for emergency braking, the air brake resistance of the train will increase by approximately 45% compared with that without the wing panel, and the vertical lift will increase by approximately 70%; ② When using wind resistance braking, the maximum pressure and average pressure on the windward surface of the brake wing plate increase in the form of parabola from the far ambient pressure value with the increase of speed, and the minimum pressure decreases in the form of inverted parabola from the far ambient pressure value; ③ The installation position of the first row of wind wing panels is within 2 m of the streamlined tail joint at the front of the driver's cab, the air resistance of the train decreases as the distance increases, and the vertical lift is basically unchanged. The range of positive and negative pressure zones formed before and after the wind wing panels gradually becomes smaller and weaker;④ When the windward angle of the first row brake wing plate is gradually expanded within 45 ° ~ 90 °, the air resistance of the train remains basically unchanged, the vertical lift increases first and then decreases slowly, and the aerodynamic interference effect and the high-pressure area on the windward surface of the wing plate are gradually weakened; ⑤ When multiple sets of brake wing panels are arranged on the roof of the head train at maximum equal intervals, as the number of wing panel arrangements increases, the air resistance experienced by the train increases slowly, and the vertical lift received remains basically unchanged. The aerodynamic interference effect between the wind wing plates gradually increased. The pressure on the windward side of the wind wing plates show that the first group is much larger than the subsequent groups, and the pressure peaks of the subsequent groups remain basically the same, with slight fluctuations.关键词：high-speed trains;aerodynamics;aerodynamic characteristics;aerodynamic noise;brake wing panel;air resistance;numerical modeling;simulation
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发布时间：2022-01-18 - 摘要：It is found that there are 18-19 order wheel polygons in the wheels of an EMU. In order to study the in fluence of wheel polygons on the vibration behavior of the vehicle, the line test of the vehicle was carried out, and the vibration acceleration of the key components was measured and analyzed. Based on the line tracking test conditions, the SIMPACK was used to establish the dynamic simulation model, and the measured wheel polygon data was used as the input. The vibration data of each key component obtained by the line experiment and the dynamic simulation was compared from the time domain and frequency domain, and the reasons for the difference of the comparison results were analyzed. The results showed that the line test data of the vertical acceleration of the frame were slightly larger than the simulation data, and the overall difference of the vertical acceleration of the axle box was small. The vibration energy of the frames in the line test and simulation test was concentrated at about 540 Hz, the vibration energy of the axle box in the simulation test was concentrated at 527 Hz, and the vibration energy of the axle box in the line test was concentrated at 542 Hz, which was close to the frequency caused by the 19th-order wheel polygon (547.81 Hz), and the fluctuation trend of the vibration energy of the two were roughly similar. The simulation test can basically restore the line test and accurately re flect the in fluence of wheel polygon on vehicle vibration behavior.关键词：high-speed train;EMUs;wheel polygon;line test;simulation
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发布时间：2022-01-18 - 摘要：Three grounding fault detection schemes of HX series electric locomotives were introduced, and it was evaluated whether there were potential electrical safety hazards when single point grounding occured in different grounding ranges under different grounding detection schemes and the locomotive continued to operate after isolating the fault converter. Through simulation analysis,when a single-point ground fault occured on the motor side, the intermediate DC link side or x-terminal of the traction transformer secondary side, no matter which ground fault detection method, the fault converter can be isolated to meet the continuous power reduction operation of the locomotive without safety risk; When the grounding fault point occured at a-terminal on the secondary side of the traction transformer, there was still a risk for the continuation in low resistance grounding mode and in the operation of isolated fault converter,which shall be stopped for rescue; There was a risk for the operation of isolated grounding fault converter in high resistance grounding mode, and the continuous operation of fault shaft can be maintained. Through the above ground fault mode analysis, it was convenient to guide operators to ensure the safe operation of locomotives and vehicles under various grounding modes.关键词：low resistance current grounding;DC circuit negative grounding;high resistance grounding;traction converter;simulation;electric locomotive
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发布时间：2022-01-18 - 摘要：Tests and finite element calculation methods were used to verify the structure and strength of the articulated equipment of the suspended modular tram with 5 modules and low floor. The finite element calculation results and test results showed that the structure of the articulated equipment met the strength requirements, and the finite element calculation method was conform to the actual situation, which could provide reference for the design and calculation of similar articulated equipment in the future.关键词：suspended modular tram;tramcar;articulated equipment;finite element
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发布时间：2022-01-18 - 摘要：In rail transit traction systems, due to the use of single-phase recti fiers, the DC input voltage of the inverter contains a ripple component whose frequency is twice the frequency of the grid-side voltage, which will cause the torque and current of the traction motor to pulsate. In order to reduce the pulsation, a beat frequency suppression control method based on a second-order generalized integrator was proposed. First, the second-order generalized integrator was used to accurately extract from the ripple component, and then the phase compensation information was injected to form the beat frequency suppression component, and finally the beat frequency suppression component was superimposed on the magnetic link to achieve beat frequency suppression. At the same time, the two optimization strategies were compared, and the optimization of the control method was realized according to the pulsation suppression effect. The simulation veri fied the accuracy of ripple components extraction and the effectiveness of low-frequency current and torque ripple suppression.关键词：traction system;ripple component;Second-order generalized integrator;beat frequency suppression;simulation;electric locomotive
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发布时间：2022-01-18 - 摘要：The design background of the FXN5C AC drive freight diesel locomotive was roughly described, and the con figuration, main technical parameters, traction and brake characteristics of the locomotive were brie fly described. The main transmission system, AC and DC auxiliary transmission system, locomotive microcomputer network control system, locomotive reconnection control,control console and electrical cabinet design schemes of the locomotive were mainly introduced, focusing on the working principle of each system, system composition and the use of parts. Finally, the evaluation status of locomotive operation was explained, and the test proved that the electrical system operated stably and reliably with excellent performance.关键词：diesel locomotive;AC drive;freight;main and auxiliary integration;electric transmission system;design
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发布时间：2022-01-18
Railway Rolling Stock
- 摘要：In order to reduce the hydrogen consumption of the fuel cell/lithium battery hybrid power system for trams, improve the rate of change of fuel cell power, and avoid the accumulation of lithium battery state of charge (SOC) power shortage or excess power supply, a coordinated control strategy of fuel cell hybrid power system for trams based on dynamic programming (DP)optimization was proposed. Based on the fuel cell hybrid power system model, the objective function of the hydrogen consumption of the fuel cell hybrid power system and the rate of change of the fuel cell power was established, and the state of charge (SOC) penalty function was introduced to constrain the SOC to be equal all the time. Through the DP global optimization, the optimal distribution sequence of fuel cell and lithium battery power was found to realize the coordinated control of the fuel cell hybrid power system.The simulation system based on fuel cell hybrid power supply system is veri fied by experiment, and the results show that: the fuel economy is improved by 44.8%, the probability of fuel cell output power in the range of 20-60 kW is 64.16%, and the change rate is signi ficantly improved; the starting and ending SOC values of lithium battery are basically consistent, which veri fies the effectiveness and superiority of the strategy proposed in this paper.关键词：fuel cell hybrid power system;coordinated control;DP optimization;tram;simulation;urban rail transit
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发布时间：2022-01-18 - 摘要：At present, the line-side over-current faults of locomotives and EMUs traction system have the problem that the diagnosis and protection methods are single and the speci fic fault source cannot be accurately located. So a real-time diagnosis method based on decision tree model was proposed. Based on the off-line analysis of the related line-side over-current fault related signals,the fault characteristics were obtained and the decision tree model was established; The real-time acquisition of signals in the process of operation and the calculation of their fault characteristics were carried out, then based on the decision tree model, the accurate fault location was realized; And different protection strategies were adopted according to the fault diagnosis results, so as to achieve the optimal protection and isolation of faults. The field test results show that the method is simple and effective, can realize real-time accurate fault diagnosis and optimal protection, and greatly improve the train availability and intelligence level.关键词：EMUs;fault diagnosis;traction system;real-time diagnosis;line-side over-current;decision tree diagnosis model
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发布时间：2022-01-18 - 摘要：The distributed power locomotive wireless synchronous control system of heavy haul combined train is the main control system designed to solve the operation of long and heavy haul combined train. In the distributed power locomotive wireless synchronous control system, the wireless train backbone network was established to realize the wireless communication of multiple connected locomotives, so as to transmit the locomotive control command and locomotive working condition feedback. Through the mutual cooperation of networks at all levels and the cooperation between locomotives, the requirements of heavy-duty combined train operation were met. Through the successful development and batch application of wireless synchronous control system for distributed power locomotive, an important technical guarantee for heavy haul freight transportation was provided.关键词：heavy-duty trains;distributed power locomotive;locomotive wireless synchronous control system;wireless reconnection grouping;synchronous control
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发布时间：2022-01-18
Electric Traction and Control
- 摘要：Hard examples for visual perception can improve the performance of object detection effectively in autonomous driving scenes. However, they are dif ficult and hard to obtain in the real world. A hard example mining method for visual perception based on multisensory fusion was presented. The obstacles target segmented from radar point clouds was used to verify the image detection targets.Hard samples of image object detection and unlabeled samples in the real open world can be identi fied by the mapping relationship of multi-sensors based on actual obstacles. These hard samples were for training a new object detection model and remote deployment through the cloud-side collaboration mechanism to realize the optimization and iterative update of the model. Experiments show that hard samples in the mining autopilot scenes can be effectively collected by this method, and be used to improve the performance of object detection through incremental transfer learning signi ficantly. In addition, the algorithm also has important guiding signi ficance for autonomous driving scenarios in rail transit and other fields.关键词：hard example mining;multi-sensor fusion;deep learning;visual perception;autonomous driving
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发布时间：2022-01-18 - 摘要：The operation in the locomotive depot is an important part for freight railway operations. The efficiency and safety of the operation in the locomotive depot directly affect the ef ficiency and effectiveness of railway operating enterprises.In this paper, an intelligent system for locomotive operations was designed to explore and research the application of automatic operation functions such as automatic wake-up and sleep, automatic maintenance, remote automatic setting of operating parameters,automatic shunting in the field of freight railway. The application effect shows that the above functions of the system improve the ef ficiency of operations in the locomotive depot, strengthen the normalization and safety of operations in the depot, and reduce the labor intensity of the operators.关键词：operation in the locomotive depot;intelligent operation;operation ef ficiency;operation safety;automatic drive
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发布时间：2022-01-18 - 摘要：Aiming at the problems of rolling bearing vibration signals were dif ficult to identify due to strong time-varying and strong noisy characteristics, a method based on adaptive wavelet analysis (AWA) and multiple layers convolution extreme learning auto-encoder (MLCELAE) was proposed. Firstly, a new method was proposed to detect the vibration signals spectrum boundary of rolling bearing, which could divide the signals spectrum adaptively, and then decompose the vibration signals into several intrinsic modal components. Secondly, the components which could best reflect the fault characteristics of the vibration signals were screened and reconstructed. Finally, the convolution extreme learning auto-encoder was constructed and multiple layers convolution extreme learning auto-encoder was built by stacking layer by layer, then the vibration signals samples of rolling bearing were fed into MLCELAE for automatic feature learning and fault identi fication. The experimental results show that the average fault identification accuracy of the proposed method reaches 98.48% and the standard deviation is only 0.17. Compared with other methods, it has more advantages in fault identi fication accuracy of rolling bearing, which is suitable for automatic identi fication of rolling bearing faults.关键词：bearing;adaptive wavelet analysis;fault identi fication;convolution extreme learning auto-encoder
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发布时间：2022-01-18
Intelligent Technology
- 摘要：According to the research requirement of vehicle satellite positioning technology, and in order to achieve the synchronization between dynamic kilometer posts in vehicle control system and satellite coordinates, the system architecture and implementation principle of the semi-physical satellite positioning simulation system were studied, the software design was completed, the simulation system was built in the indoor environment, and the function of the system was veri fied by application test. The results of the test indicated that under indoor simulation condition, the satellite dynamic signal was compatible to the actual line. Furthermore, the system showed a short latency and small deviation, which could be used as a research experimental lab for vehicle positioning with BDS or GPS.关键词：railway kilometer post;train positioning;semi-physical simulation;on-board train control
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发布时间：2022-01-18
Communication and Signal
- 摘要：During the operation of HVDC system with the earth as the loop, the formed current field in the ground has corrosion effect on the adjacent high-speed railway system. A complete high-speed railway comprehensive grounding equivalent model and high-speed EMU electrical model were established, the existing DC path was analyzed, and the "Π" type equivalent circuit suitable for high-speed railway simulation modeling was extracted. The simulation models of various typical scenes of high-speed railway were established by using CDEGS software. Through the simulation analysis of different soil resistivity and vertical distance between grounding electrode and railway, the DC current flowing through traction power supply system and EMU under different external conditions was compared. The results show that there are differences in DC parameters in different high-speed railway sections. The higher the soil resistivity, the smaller the vertical distance between the grounding electrode and the railway, and the greater the DC current flowing through the traction transformer of EMU; When the soil resistivity along the line is less than 300 Ω·m and the vertical distance between the grounding electrode and the railway is more than 5 km, the DC magnetic bias effect of EMU traction transformer meets the requirements of the regulations.关键词：HVDC;grounding electrode;ground current;high-speed railway;high-speed EMU;DC bias;excitation;simulation
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发布时间：2022-01-18 - 摘要：When the 24-pulse recti fier has failed, the amount of fault signal generated was large, and the sparsity was low, so the fault warning cannot be accurately performed. A method based on compressed sensing theory (CS) was proposed for fault signal recovery and reconstruction. Firstly, the 24-pulse recti fier model was built in MATLAB to simulate the fault signal. Secondly, the original fault signal was sparsely represented by redundant dictionary, and a piecewise orthogonal matching pursuit (Dice-StOMP)algorithm based on Dice coefficient similarity matching criterion was proposed, which used Dice coefficient similarity matching criterion to replace the inner product metric matching criterion, so as to optimize the support set and recover the original signal.Finally, the validity of the model and the superiority of the algorithm were veri fied in MATLAB. The simulation results show that the built model can correctly simulate the fault signal, and the proposed algorithm has higher reconstruction accuracy and shorter reconstruction time than other recovery algorithms.关键词：24 pulse recti fier;compression sensing;redundant dictionary;Dice-StOMP algorithm;signal reconstruction;simulation;fault diagnosis
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发布时间：2022-01-18
Railway Electrification
- 摘要：Aiming at the over voltage problem of long cable caused by high-speed switch devices such as silicon carbide, the mechanism of over voltage of long cable and its in fluencing factors were analyzed, and a method of suppressing over voltage of long cable based on interphase transformer was put forward, which was veri fied by modeling simulation, double pulse circuit and buck circuit test. The results showed that the method was effective in suppressing over voltage of long cable obviously.关键词：PWM pulse;transmission line;characteristic impedance;over voltage;interphase transformer;simulation
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发布时间：2022-01-18
Reliability Engineering
- 摘要：The physical structure of IGBT module package was introduced, and the main mechanism of chip failure caused by heat shock was analyzed. The main transfer path of chip heat loss was analyzed, the transient heat-transfer model of each link of heat transfer was established, and the calculation method of transient temperature rise of each link was given respectively. The heat transfer model of heat pipe radiator cooled by the moving vehicle wind was complex, so the detailed analysis and experimental study were carried out particularly.An effective method to obtain the real-time parameters of the radiator thermal impedance model was found. Finally, the calculation method of transient junction temperature was summarized and the software tool was developed. The calculation method and software tools introduced can be widely applied and provide important reference for transient chip temperature calculation of IGBT module.关键词：IGBT;diode;heat loss;thermal impedance;junction temperature;metro vehicles
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发布时间：2022-01-18
High-power Devices
- 摘要：In the field of intelligent operation and maintenance of subway trains, the detection of abnormal appearance of trains is an indispensable important link. From traditional manual inspections to 2D imaging image recognition methods of line array cameras, there are certain defects, which are not enough to achieve fast and accurate intelligent inspections. The image recognition method based on 2D imaging can solve the problems of slow manual inspection and missed inspection caused by fatigue. However, the abnormal problems that occur in the third dimension perpendicular to the imaging plane have not been well resolved. A bolt looseness detection method based on 2D/3D imaging was proposed, which avoided the impact of excessive changes in image pixel values caused by light, water stains, gray layers, etc. on the detection results in 2D imaging, and can be applied to abnormal detection of subway trains very well.关键词：subway;3D detection;plane fitting;area growth;loose calculation
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发布时间：2022-01-18
Detection Technology
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