最新刊期
卷 ， 期 5 ， 2022
- 摘要：Cooling system is an important subsystem of power concentrated EMU. The cooling performance, volume, weight, auxiliary power and noise control of cooling devices are the technical bottlenecks and difficulties in product research and development, which directly affect the reliability, economy and environmental friendliness of EMU operation. In order to satisfy the cooling requirement of traction system components including traction transformer, traction converter and power supply cabinet in limited space, make the structure more compact, reduce the cooling unit weight and auxiliary power consumption, control noise, and improve the radiator fouling resistance and maintainability, a composite cooling tower for 160 km/h power concentrated EMU was developed. The cooling tower adopted the optimized design of water-oil integrated compound radiator with high cooling efficiency, and axial flow fan with optimized impeller, guide vane, air duct structure, which had high efficiency and low noise. The whole structure was designed as a lightweight overall aluminum bearing structure. This paper introduced the overall structure, working principle, technical design, simulation analysis and test verification of the composite cooling tower for 160 km/h power concentrated EMU. By comparing with the existing typical composite cooling tower for electric locomotive, the paper shows that the composite cooling tower for 160 km/h power concentrated EMU is more advanced in terms of multi-system matching, efficient heat dissipation, low noise, energy conservation and lightweight design.关键词：power concentrated EMU;traction transformer;traction converter;composite cooling tower;cooling efficiency;noise;lightweight;energy conservation
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发布时间：2024-08-02 - 摘要：Against the problem of insufficient lateral flexibility due to the design space limitation of secondary springs of the bogie for a suspended monorail train, an equivalent restoring stiffness formula was deduced from the linear theory of small swing angles for the four-linkage suspension mechanism. Based on the formula, the geometric parameters optimization of suspension system was completed, and the lateral stiffness of the suspension system was improved to the level equivalent to the secondary air spring used on metro trains. Combined with the actual design cases of suspended monorail trains, the four-link suspension mechanism was analyzed from the view of kinematics and dynamics using the multi-rigid-body dynamics approach. The applicability scope and limitation of the equivalent restoring stiffness formula were summarized, and a 3D coupling dynamics model for the whole train was established to analyze and verify the effectiveness of the optimized design solution of the suspension system. The results show that the design solution by reasonably matching the geometric parameters of the four-linkage mechanism can significantly improve the lateral riding quality of the train, but when the train passes through a small radius curve, it will cause more dynamic deviation of the train body.关键词：suspended monorail vehicle;four-linkage;restoring stiffness;optimization;urban rail transit;simulation
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发布时间：2024-08-02 - 摘要：Flange thickness is an important parameter measuring wheel size of locomotives. In recent years, the problem of flange thickening over the specified limit has become particularly prominent, which not only increases the maintenance cost, but also reduces the locomotive turnover rate. Moreover, excessive losses due to reprofiling bring an adverse effect to the service life of wheels. In this paper, the principle of flange thickening was firstly analyzed, and it was found that the change in measurement standard and the improvement of locomotive operating track conditions are the main influencing factors. A flange thinning model was built based on the wheel tread contours with thin flanges specified in the Chinese railway standard, and analysis was performed in consideration of the actual flange change of each wheel, to generate the reprofiling plans to maintain their wheel tread contours with the optimum flanges. In addition, the flange thinning model was added to the economical reprofiling model, and the technical indicators such as flange thickness, reprofiling amount, reprofiling order, and reprofiling craft requirements were determined, integrating the factors such as the initial reprofiling amount and the requirements of wheel diameter difference into account, such achieving customization for wheel reprofiling plans, and expanding the application scope of economical reprofiling model. An application system was built based on the improved wheel reprofiling model, which was applied in trial to the locomotive wheels at the depot, and the improved model was verified in actual conditions. In the two-month trial application, flange thinning reached a proportion of 78%, with an average thinning of 0.83 cm and the average reprofiling amount per wheel down by 7.94%. It can be seen from the verification results that the model can not only reduce the reprofiling proportion of locomotives with thickened flanges, thus improving the turnover rate of locomotives, but also effectively reduce the average reprofiling amount of wheels, to prolong their service life, demonstrating the value of promotion and application.关键词：locomotive wheel;flange thickening;flange thinning model;improved wheel reprofiling model;model effect verification
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发布时间：2024-08-02 - 摘要：Considering that the entire electric multiple unit (EMU) needs to be withdrawn from service for carrying out preventive maintenance (PM) of the critical equipment, leading to an increase to downtime loss, the concept of replacement repair is proposed in this paper. Specifically, based on the preventive maintenance schedule, the involved critical equipment is replaced with another set of equipment with good performance and then delivered for maintenance, so as to overcome the shortage of sudden increase of service suspension loss caused by preventive maintenance. This paper took the EMU critical equipment as the research object. The preventive maintenance models were built respectively based on replacement repair and non-replacement repair, with the preventive maintenance reliability threshold as the decision making variable, the total maintenance cost of the EMU critical equipment in a replacement cycle as the decision making objective, and applying the 2-level imperfect maintenance measure for the EMU critical equipment. Based on the example analysis, the optimization results of preventive maintenance reliability threshold based on replacement repair are higher than that based on non-replacement repair, and the total maintenance cost of replacement repair is 22.2% lower than that of non-replacement repair. Therefore, the preventive maintenance strategy of the EMU critical equipment based on replacement repair can greatly reduce the total maintenance cost of equipment in a life cycle and can maintain the equipment at a higher reliability level.关键词：electric multiple unit (EMU);critical equipment;downtime loss;replacement repair;total maintenance cost;high-speed train
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发布时间：2024-08-02 - 摘要：In order to study the safety of EMUs under high-speed collision with large animals, a three-dimensional curved surface model of deer was generated through physical scanning and data processing, and then a finite element stack model of deer was established. With a kind of elastic-plastic material selected to simulate deer’s body skeleton, which can simulate skeleton damage by inputting the plastic failure strain in the parameter field of material attributes, and a constitutive model of linear elastic materials was selected to simulate their muscle and skin, and the pendulum side collisions were carried out for verification. By analyzing the spatial relationship between the EMUs head and animals crossing the track, and referring to the definitions of frontal collision and offset collision between trams and pedestrians specified in CEN/TR 17420: 2020 standard, two collision scenarios, i.e. frontal collision and offset collision, were set between the train at the maximum operating speed of 160 km/h and deer invading the track. The results of the finite element simulation analysis are as follows. Under the frontal collision scenario, the mean deceleration of the body of the head car is the highest, and the maximum mean deceleration in any 30 ms and 120 ms intervals is 0.73g and 0.21g respectively, which is lower than the requirements of 10g and 5g specified in EN 15227 standard; The maximum wheelset lifting amount is 1.64 mm, which is far less than 75% of the nominal flange height of 28 mm. In the offset collision scenario, the mean deceleration of the body of the head car is the highest, and the maximum mean deceleration in any 30 ms and 120 ms intervals is 0.53g and 0.13g respectively, which is lower than the requirements specified of 10g and 5g in EN 15227 standard; The maximum wheelset lifting amount is 1.75 mm, which is far less than 75% of the nominal flange height of 28 mm. Under the two collision scenarios, the carbody structure, coupler, anti-creeper, main energy absorber and pilot are free of plastic deformation, and all the evaluation indicators meet the requirements of EN 15227:2020 standard, which indicates that the designed EMUs is safe and reliable, and the carbody can withstand high-speed collisions of deer or other large animal.关键词：EMUs;large animal;crashworthiness;safety;finite element;simulation
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发布时间：2024-08-02 - 摘要：Because straddle monorail vehicles run on rubber wheels, the contact status between the pantograph and the catenary is hard to control, and the abrasion on the current-receiving sliding block on the pantograph is serious. In order to reduce the abrasion on the sliding block, a sensitivity analysis method was used in this paper to analyze the influence degree of vehicle dynamics parameters on the coupling force of pantograph and catenary based on the dynamic simulation analysis model of "vehicle-pantograph-catenary" system. The average value of the pantograph-catenary contact force was considered as the optimization objective, and dynamics parameters of the vehicle were optimized by non-dominated sorting genetic algorithm (NSGA-II). The results show that the rigidness of the running tires and the guide tires has a great influence on the pantograph-catenary contact quality , and the standard deviation of the contact force decreases to a certain degree at different speed after parameter optimization. The abrasion problem of pantograph sliding block of straddle monorail vehicle can be improved by optimizing the radial rigidness of tires.关键词：straddle monorail;dynamics;pantograph-catenary contact quality;optimization;catenary;track irregularity;urban rail transit
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发布时间：2024-08-02 - 摘要：A 1-D longitudinal dynamics model was built with two type B metro trains of the same consist under longitudinal impact with each other, and the energy absorbing elements at the end of cars were modelled and simulated (including the reversible energy absorbing elements such as the rubber draft gear and irreversible ones such as the collapsible tube and anti-creeper). The parameters for the irreversible energy absorbing elements (collapsible tube) at the end of cars were optimized, for the sake of meeting multi-stage energy absorbing in train collisions, and comparative analysis was conducted on energy absorption in sections under the scenarios of a constant resistance force pattern, multistage resistance force pattern, and gradient resistance force pattern. According to the results, the variable resistance force pattern gives the energy absorbing element the best performance to meet the energy absorbing requirement at different speeds in collisions, to the benefit of uniform distribution of energy absorbing across sections, as the best solution to tackle the contradiction between a limited space between cars and insufficient energy absorbing stroke. Furthermore, the gradient resistance force pattern presents a better energy absorbing performance than the multistage resistance force pattern. The simulation results may serve as a reference in the parameter configuration of the energy absorbing elements in the coupler and draft gear system, especially the collapsible tube.关键词：metro;energy absorbing;parameters;optimization;coupler;simulation
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发布时间：2024-08-02 - 摘要：In the medium and low speed maglev vehicle-rail coupling system, the turnout is an important part of the line change of the maglev vehicle, and its main beam mostly adopts the web or box-shaped steel beam structure with relatively low modal frequency and damping. When the maglev vehicle passes the turnout at a certain speed, it is easy to couple vibration with it, which affects the running stability and driving safety of the vehicle. For this reason, this paper took Changsha medium and low speed maglev vehicle as a prototype, established a maglev vehicle-turnout beam coupling system model, and analyzed the vibration response of the maglev vehicle-turnout beam coupling system by studying the magnetic-rail interaction relationship and vibration control method of the coupling system. In addition, a tuned mass damper (TMD) based on dynamic vibration absorption was proposed, and its effectiveness in suppressing the vibration response of a maglev vehicle-turnout beam coupling system was demonstrated. The research results show that the feedback coefficient of the control system can change the magnetic-rail interaction relationship of the coupled system to different degrees, and the gap feedback coefficient and the velocity feedback coefficient have obvious effects. The speed of the vehicle has a significant effect on the vibration response of the vehicle body and the active beam of the turnout, the medium and low speed maglev vehicles are more sensitive to the speed within 40 km/h when passing through the steel beam of the variable cross-section switch. During the operation of the maglev vehicle, the lower modes of the turnout beam are more easily excited, which is the key factor that causes the resonance of the maglev vehicle-turnout coupling system. The principle of tuning the mass damper device is to adjust the vibration frequency of the TMD device to the vicinity of the vibration coupling frequency of the main structure of the switch beam by increasing or decreasing the weight of the device, and to change the resonance characteristics of the switch beam by means of dynamic vibration absorption, so as to achieve the effect of suppressing the coupled vibration of the turnout beam. The comparative analysis in this paper shows that TMD controller has obvious effect on improving the stability of maglev vehicle-turnout coupling system, it is an effective coupled vibration control measure.关键词：medium and low speed maglev vehicle;coupling vibration;variable section turnout beam;TMD control;suspension stability;urban rail transit
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发布时间：2024-08-02 - 摘要：Single-type low-floor trams have been widely used in the construction of urban light rail transit in recent years. As a common component of low-floor trams, the rotation stopping block can limit the relative swing angle range between the car body and the bogie. Its design scheme has a great impact on the movement attitude and dynamic performance of the vehicle when it passes through the small radius curve line. Determining the arrangement of the rotation stopping block on the bogie is the basis for the design of its structure and mechanical properties. At present, there are few studies on the rotation stopping block. The arrangements of the rotation stopping block and its influence have not been paid attention to. In this paper, for single-type low-floor vehicles with different arrangements of rotation stopping block, an optimization method for the rotation stopping block gap was proposed, which comprehensively considered the requirements of vehicle’s gauge and dynamic performance. The influence of different rotation stopping block arrangements on vehicle dynamic performance was studied. A design was proposed which could make the dynamic performance of the vehicle better under the condition of ensuring the same results of the vehicle gauge check. The research results show that when the vehicle passes through the small radius S-shaped curve line, with the reduction of the rotation stopping block gap, it is easier for the vehicle to meet the gauge requirements, but the curve passing safety become worse; With the premise of design conditions permitting, comprehensively considering the requirements of the vehicle’s gauge and dynamic performance, the lateral arrangement of the rotating stops is more suitable for single-type low-floor trams; If the rotation stops need to be arranged longitudinally due to the design conditions, the secondary lateral stop can be adjusted and optimized to obtain an optimized design scheme for the vehicle with better dynamic performance.关键词：low-floor tram;rotation stopping block;dynamic performance;gauge;urban rail transit
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发布时间：2024-08-02 - 摘要：Taking the sanding device of an electric multiple unit (EMU) as the object of study, which suffered from weld cracking in the service process, investigation was carried on its random vibration fatigue problem. Firstly, the stress response at the key part of the sanding device was studied by the vibration test bench and under the load spectrum defined in IEC 61373, and the random vibration fatigue was evaluated by using the frequency-domain lifetime evaluation method. Secondly, a random vibration model of the sanding device was established, based on the rigid-flexible coupling method and considering pseudo excitation, to simulate the test vibration environment of the sanding device. The stress response at the key part of the sanding device was got by using the modal stress recovery method, and the model correctness was verified from the aspects of stress time history and power spectral density. Finally, this model was further used to investigate the random vibration fatigue lifetime of the sanding device under the measured vibration environment. The results show that the Dirlik method can evaluate the amplitude distribution of the stress rainflow matrix more accurately than the Zhao-Baker method. The proposed random vibration model of the sanding device based on pseudo excitation can effectively simulate the vibration environment under the test, thus accurately simulating the stress response at the key part of the sanding device. Compared with the measured line data, the vibration spectrum for the axle-mounted components given in IEC 61373 overestimates the vibration amplitude in the low frequency range, and ignores the vibration energy over 500 Hz. Under the action of the wheel polygonal wear, the stress amplitude of the sanding device close to 500 Hz is significantly enlarged, resulting in the greatly reduced service lifetime of the sanding device.关键词：EMU;sanding device;vibration fatigue;vibration test;high-speed train
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发布时间：2024-08-02 - 摘要：The lightweight design of the car body structure in EMUs leads to an increase in structural flexibility, and with the increase in the operating mileage and the deterioration of wheel-rail wear, the car body suffers from worsening abnormal elastic vibrations during operation, such as jittering and lurching, which affect riding comfort and operational safety. This paper was intended to analyze the causes of such abnormal vibrations, from the perspectives of modal contribution, modal design and modal control. Firstly, based on the modal correction and modal test results of the car body, a finite element model of the car body was established. Secondly, according to the working conditions, the car body was processed into a free modal, and the structural modal parameters were extracted. Then, based on the modal analysis theory and the principle of modal contribution, the elastic modal shapes of the car body structure were analyzed, and the structural modal contribution factor was calculated according to the car body modal displacement. Finally, the modal matching method and transfer function method were analyzed for the elastic vibration control of the car body. The results show that the modals that contribute greatly to the vertical vibration of the car body in the order of magnitude are as follows: the first-order vertical bending, the first-order diamonding, the second-order diamonding, and the first-order torsioning, and the modals that contribute greatly to the lateral vibration in the order of magnitude are as follows: the first-order lateral bending, the first-order diamonding, the second-order diamonding, and the first-order torsioning. The main factors that cause the elastic vibration of the car body are the track disturbance, the bogie hunting motion, the bogie modal, and the suspension parameters of the underfloor equipment. The rigid natural vibration frequency of the wheelset, frame, car body and other EMU components should meet the vibration isolation requirements, and the first-order diamonding elastic modal frequency of the car body should be effectively isolated from the rigidity and elastic frequencies of the frame, to reduce abnormal elastic vibration of the car body. An increase in the damping ratio of the car body structure can reduce the amplitude of the acceleration transfer function and improve the riding comfort. Specifically, an increase in the damping ratio of the car body structure from 0.015 to 0.150 can improve the running stability index by 13%, so increasing the structural damping can significantly reduce car body vibration.关键词：EMU;car body;modal analysis;modal contribution;modal matching;transfer function;high-speed train;track irregularity
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发布时间：2024-08-02 - 摘要：The polygonal evolution of wheels affects the operational safety of EMUs. In order to study the evolution process and its effect on vehicle vibration behaviors, the wheel profile of an EMU in China was measured and analyzed. Based on the vehicle dynamics theory and rolling contact theory, a vehicle-rail coupling dynamics model was established, and the characteristics of polygonal wear were simulated from angles of view of the time domain and frequency domain. Assuming that the lateral wheel profile and nominal wheel radius were unchanged, a long-term wear iterative model was established in combination with the USFD wear model, to simulate the polygonal evolution behaviors, and the effect on the dynamic performance was analyzed on the basis of the measured out-of-roundness data. The results show that there is a phase difference between the final circumferential profile and the initial profile, and the waveform changes little with worsening wheel wear. The wheel polygon has little effect on the running stability index, but it affects the wheel-rail dynamic interaction. The maximum wheel-rail vertical force decreases with the increase of wheel out-of-roundness wavelength, and increases with the increase of speed and roughness amplitude. At the same driving speed, the vertical acceleration amplitude of the frame increases with the increase of the roughness amplitude.关键词：wheel polygon;wear iteration;evolution behavior;dynamic performance;measured profile;EMUs;track irregularity
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发布时间：2024-08-02
Railway Rolling Stock
- 摘要：In order to meet the requirements of running over-long, diesel-electric hybrid and power-distributed heavy haul train formations, a multi-mode marshaling was proposed, supporting the diesel-electric coupling and eight-locomotive coupling. Moreover, a formation solution with 40 electric and diesel locomotives coupled in five consists in a wired manner was realized, in coordination with the distributed power (DP) system. In the support of this solution, more heavy haul trains could be operated in the sections without increasing power supply capacity, and the requirements of heavy haul transport with mixed locomotives of different types could be met. The effectiveness of this solution has been verified on an electric locomotive project in South Africa.关键词：heavy haul train;formation with coupled locomotives;electric-diesel coupling;multi-mode;multi-locomotive coupling;distributed power;heavy haul railway
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发布时间：2024-08-02 - 摘要：Metro trains have the advantages of high starting acceleration, high operating speed, punctuality and large carrying capacity, but energy consumption is also an important issue that needs close attention in metro operation. How to further improve the efficiency of energy conservation for metro trains has become a key point in the design of traction system. Compared with traditional asynchronous traction system, the direct-drive permanent magnet traction system with high driving efficiency and good corner-passing performance is one of the directions for the research and development of traction and transmission technology used in rail transit system. Benchmarking the performance indicators of traditional asynchronous traction system, a direct-drive permanent magnet traction system was developed based on the design and model selection of the direct-drive permanent magnet synchronous motor on the train of Xuzhou metro line 1. According to the characteristics of direct-drive permanent magnet traction system, a new full-speed range position sensorless control technique for permanent magnet synchronous motor and an adhesion control technique adapted for direct-drive permanent magnet system were used to realize real-time control of the traction inverter and direct-drive permanent magnet synchronous motor. The on-vehicle test showed that the direct-drive permanent magnet traction system has such advantages as stable motor position identification and fast response, and the traction force is stable and efficient with low adhesion on rail surface. The energy consumption comparison test showed that the direct-drive permanent magnet traction system was 22.7% higher than asynchronous traction system in terms of energy conservation, indicating significant energy saving performance. The direct-drive permanent magnet traction system, which is compact and energy efficient, has positive significance for promoting the further development of the rail transit industry.关键词：Xuzhou metro;direct-drive permanent magnet traction;permanent magnet synchronous motor;position sensorless;adhesion control;water cooling device;metro train
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发布时间：2024-08-02 - 摘要：The state of health (SOH) of nickel-cadmium battery used on EMUs influences the operation safety of trains. Due to the complex working conditions of EMUs, the existing SOH monitoring methods are unable to realize good online monitoring. To study the change tendency of battery SOH and realize online prediction, this paper proposed an online SOH prediction method based on the charging time under constant voltage rise, with the assumption that there is no discharge when using charger to charge the battery. This method determined the optimal constant voltage rising range (i.e. the voltage difference between the start and end of charging) through a comprehensive correlation analysis of charging time under constant voltage rise and battery SOH based on moving voltage window, and then extracted the optimal charging time under constant voltage rise from the voltage range as the input for the long short-term memory (LSTM) model. The sparrow search algorithm (SSA) was used to optimize the LSTM parameters, establishing a battery SOH prediction model, and realizing the online prediction of battery SOH. The test results show that, compared with traditional LSTM and back propagation (BP) neural network, the battery SOH prediction model based on SSA-LSTM has higher prediction accuracy.关键词：EMUs;nickel-cadmium battery;SOH prediction;charging time under constant voltage rise;SSA-LSTM
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发布时间：2024-08-02 - 摘要：In the process of circulating air brake control of intelligent driving heavy haul train with the formation of 3+0, because the magnitude of air braking force is affected by various factors such as railway line conditions, vehicle load, friction characteristics of brake shoes, differences in pipelines, and intermittent working characteristics of air brakes, it is difficult to accurately plan and control trains, even causing potential safety hazards. To solve this problem, this paper proposed a prediction method for the strong and weak of air braking force based on IPSO-SVM (Improved Particle Swarm Optimization-Support Vector Machine). IPSO was used to optimize the parameters of SVM. The main factors affecting the magnitude of air braking force were used as the input of SVM to evaluate the strong and weak of air braking force, and the analysis and verification were carried out based on the measured data of Shenmu-Shuozhou railway. The results show that the prediction accuracy of the proposed method can reach more than 90%, which verifies the method is rational and effective, having good and practical value in engineering application.关键词：heavy haul train;intelligent driving;air braking;IPSO;SVM
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发布时间：2024-08-02 - 摘要：In a multiple-pole and high-power PMSTM with high fundamental frequency, the harmonic frequency of the internal magnetic field increases accordingly. The harmonic magnetic field will induce eddy current in the winding, resulting in high-frequency eddy current loss,, which will cause additional copper loss to be greatly increased, and should not be ignored in the design process. AC winding loss is the sum of DC winding loss and eddy current loss. The sources, calculation methods and influencing factors of AC winding loss of PMSTM with high frequency and power were studied. A detailed FEA model of an 8-pole 675 kW high-frequency PMSTM was established. The influence of stator slot opening depth, winding conductor parallel number, rotor rotating magnetic field and time harmonic of input current on AC winding loss were analyzed. The calculation results show that the harmonic magnetic field has the greatest influence on the conductor current density distribution near the slot opening; Optimizing the slot opening depth and winding conductor parallel number can effectively reduce the eddy current loss of the winding, minimize AC winding loss, and improve the efficiency of PMSTM.关键词：eddy current loss;winding AC loss;skin effect;proximity effect;finite element analysis;PMSTM;simulation
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发布时间：2024-08-02 - 摘要：Focusing on the eco-driving for supercapacitor trams, considering traction/braking characteristics, trip operation time constraint, variable value of slope and power constraints of supercapacitor, a modified dynamic programming method was proposed with consideration the optimal manipulation derived from the maximum principle. Firstly, the system model was introduced, and an optimization problem was constructed. Then, eco-driving regimes of supercapacitor trams were analyzed based on the maximum principle. The state space of velocity trajectory was constructed integrating dynamic programming. Finally, the bi-section method was utilized to find optimized eco-driving speed profiles to satisfied the trip time constraint. Simulation results show that the better solve efficiency and quality can be obtained by the modified dynamic programming compared to the traditional dynamic programming. The high utilization rate of regenerative braking for supercapacitor trams increases the usage of electric braking condition and shrinks the usage of coast condition.关键词：urban rail transit;energy saving optimization;regenerative braking;supercapacitor tram;adaptive dynamic programming;simulation
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发布时间：2024-08-02
Electric Traction and Control
- 摘要：In electrified railway operation, it is easy to result in low-frequency oscillation if the electrical parameters of the locomotive and the traction network are mismatched. This will not only hamper the power supply protection of the traction network, but also lead to blocking of the locomotive’s traction system, posing severe threats to the safe operation of traction network and locomotive. To better suppress the oscillation, this paper presented an optimized oscillation suppression strategy and parameter design method. Firstly, after describing the equivalent circuit topology and control strategy of the vehicle-network system, a closed-loop small signal model of the system was modeled according to small signal theory. Then, on the basis of stability analysis, an optimized oscillation suppression method was proposed based on active damping control, aiming to improve the dynamic performance of the suppression strategy. As for the issue that excessively large coefficient for active damping control would influence the steady-state performance of the system, the minimum value of active damping control coefficient was determined according to Routh stability criterion. At last, the results of the test on time-domain simulation model verified the effectiveness of the optimized suppression method and the rationality of its parameter design.关键词：low-frequency oscillation;vehicle-network system;active damping;suppression strategy optimization;parameter design
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发布时间：2024-08-02 - 摘要：The pantograph-catenary system is a key part of power supply for electric locomotive, and its operating status determines the current receiving quality of electric locomotive, as well as safety and efficiency of trains. In order to solve the problems of traditional method for inspection of pantograph-catenary status, such as low efficiency and poor performance in real time inspection,this paper designed an online pantograph-catenary status inspection system solution based deep learning. The solution adopted NIDIA Xavier SoC module to perform image processing, and realizes pantograph-catenary inspection by YOLO v4 and adaptive image enhancement module was also added. The mAP of inspection target before and after optimization was 0.950 and 0.961 (with the IOU threshold of 0.5) respectively. Classification of catenary dropper status based on ViT lightweight class attention model was realized at an average accuracy rate of 97.69%. After acceleration by using NVIDIA TensorRT accelerator, the inference time of inspection model and classification model were 31.0 ms and 2.2 ms respectively. The system has high robustness and practicability, which can provide theory basis and design reference for online inspection function of pantograph-catenary abnormality in the future.关键词：pantograph-catenary status inspection;catenary;dropper;deep learning;TensorRT;ViT;YOLO v4
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发布时间：2024-08-02 - 摘要：Currently, many metro lines use ground energy storage facilities to gather regenerative braking energy of trains. The capacity configuration of the energy storage facility is closely associated with the characteristics of regenerative braking power of traction load in the power supply section. However, traditional diode rectifier unit of traction substation cannot transmit the regenerative braking energy back to the power grid, thus bringing difficulties in obtaining the data of regenerative braking power of the traction power supply section through field testing, so the configuration of the capacity of energy storage device lacks data support. This paper proposed a traction load modeling method based on the probability distribution of single train power and the probability distribution of the number of trains in the power supply section, and traction load simulation was used to realize the multiple-target optimization configuration of energy storage facility capacity. This method first established the power probability distribution model of a single train under different working conditions, and then used Poisson distribution to model the number of trains in the power supply section, and then obtained the traction load model considering the time sequence of train. At last, artificial fish swarm algorithm was used to identify the parameters of the proposed traction load model. The probability density of the positive part of traction load power generated by detailed example was compared with the measured data, and the results had verified the accuracy and validity of the modeling.关键词：metro;regenerative braking;probability distribution;traction load;artificial fish swarm algorithm;urban rail transit
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发布时间：2024-08-02 - 摘要：When establishing the dynamic mathematical model of traction power supply system for urban rail transit, it is necessary to solve the group of ordinary differential equations. However, because the traction power supply system of urban rail transit is a typical rigid system with complex topology and time-varying parameters, deviation between the simulated result and the reality exists in dynamic simulation when the traditional time-discrete algorithm is used to simulate the system. Therefore, a hybrid simulation method combining traditional time discretization and the quantized state system algorithm was proposed. Firstly, according to the varying rates of state variables, the system model was divided into two subsystems: large step solution and small step solution. The state variables of small step subsystem with fast-varying rates were quantized and discretized, and the pseudo-oscillation of simulation value was reduced by improving the quantized state system algorithm, while the traditional time discretization algorithm was used to improve the computational efficiency for the state variables of subsystems with relatively slow changes and large steps. Secondly, the dynamic mathematical models of multi-pulse uncontrolled rectifier unit and the power source train of the urban rail traction power supply system were established by using the ordinary differential equations, and the real-time power flow analysis of AC and DC side of the model was implemented by using the mixed simulation method of quantized state time discretization in MATLAB. Then an equivalent model was established in Simulink, and the waveforms obtained by using this algorithm were compared with the Simulink simulation waveforms to verify the accuracy of this method. Finally, the simulation time and step length of different methods were compared under the same simulation conditions. The results show that the quantized state time discretization hybrid solution method is feasible, accurate and efficient in the dynamic simulation system of urban rail traction power supply.关键词：urban rail transit;traction power supply;ordinary differential equation;quantized state system;rigid system;simulation;multi-pulse uncontrolled rectifier
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发布时间：2024-08-02
Railway Electrification
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