最新刊期
卷 ， 期 2 ， 2023
- 摘要：As the core component of electrification process, the power semiconductor device keeps improving, and constantly promotes the development of electrification devices and applications. The key technologies of power semiconductor devices mainly include four aspects: new material, new structure, new package and intelligence. The requirements for power semiconductor devices are different in different application scenarios. By analyzing the characteristics of typical application scenarios of rail transit, electric vehicle and electric power system, this paper analyzed and described the applications of fine trench insulated gate bipolar transistor, silicon carbide and intelligent integrated power devices with high power density. At present, power semiconductor devices are still in a rapid and steady development stage. Existing technologies are maturing and new technologies are emerging, there is a huge space for the development of key technologies in the four aspects.关键词：power semiconductor device;new material;new structure;new package;intelligence;typical applications
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发布时间：2024-08-02
Special Report
- 摘要：Bogie is the running device that supports, pulls and realizes the brake of vehicle body, buffers vibration and rotates relative to the vehicle body, which determines the safety, reliability and quality of train operation. The bogie of China's high-speed EMU has undergone three stages of development: technology introduction, innovation based on absorption, and independent innovation. Through continuous technological innovation and practice, achievements have been made in key technologies such as structural lightweight, safety and reliability, dynamic performance, and intelligence. The scientific research and testing conducted on test benches, circular tracks, and dedicated testing lines for the structural strength and dynamic performance of bogies, as well as the long-term service tracking testing of the lines, have laid a solid foundation for theoretical research and engineering practice and the independent development of China's high-speed EMU bogies in the stage of independent innovation. This paper systematically reviews the structural parameters and technical bottlenecks of China's high-speed EMU bogies in three development stages, and points out the technical research direction of the next-generation high-speed EMU and CR450 bogies. From the perspective of the basic structure of bogie, this paper systematically discusses the development process and trend of bogie's overall integration, frame, wheel-set axle box and positioning device, suspension device, driving system, foundation braking and auxiliary device, and puts forward the research direction of technological independent innovation and engineering application innovation. This paper also discusses the research status and development direction of five key technologies: lightweight design of bogies, strength reliability, vehicle system dynamics, intelligent design, and experimental testing.关键词：high-speed EMU;bogie;structural design;strength reliability;vehicle system dynamics;intelligence;high-speed train
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发布时间：2024-08-02
General
- 摘要：In view of the crosstalk problem in the application of SiC MOSFET module, this paper first conducted a comparison of the parameters and measured waveform of three types of measuring differential probes to effectively reduce measurement error. Then, the reasons why crosstalk causes excessive forward voltage and excessive negative voltage at the gate and source were analyzed in detail, and three effective countermeasures in application were provided, including reducing gate impedance, using active Miller clamping and three-level turn-off crosstalk suppression circuit. Reducing the gate impedance could suppress the amplitude of gate voltage and reduce induced voltage drop. By using active Miller clamping technology, the amplitude of the gate source voltage crosstalk waveform was limited to the clamping voltage range. By utilizing three-level turn-off crosstalk suppression circuit technology, the forward uplift and negative peak of gate source voltage was suppressed significantly. The effectiveness of the three methods was proved by experiment and simulation.关键词：crosstalk problem;voltage at the gate and source;gate impedance;active Miller clamping;three-stage off level driving technology
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发布时间：2024-08-02 - 摘要：In order to improve the copper wire bonding performance of the power modules, an optimization design scheme of process parameters for copper wire bonding was proposed by using the six-factor five-level orthogonal test method, and combining the back propagation (BP) neural network and genetic algorithm (GA). Firstly, the selected samples were orthogonally tested and the results were analyzed by range analysis to generate the influence weight ranking of the process parameters on the bonding quality. Secondly, a prediction model of copper wire bonding performance was constructed using the BP neural network, and the optimal values of process parameters were generated by solving the BP neural network fitness function with GA. Comparing the optimization results from the BP genetic algorithm with those from the traditional methods, the former was found in the stability of the copper wire bonding process improved more significantly. Finally, the power cycle test was carried out on the power module, showing that the power cycle capability of the module optimized by the BP genetic algorithm was significantly improved.关键词：copper wire bonding;BP neural network;genetic algorithm;optimization of process parameters
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发布时间：2024-08-02 - 摘要：The paper presents a new type of gate driver for IGBT, which has the function of acquiring the operation state data in addition to traditional gate drive and short-circuit protection functions. Acquiring data of IGBT in normal operation state and at fault is conducive to understanding the working environment of IGBT, analyzing IGBT failure mechanism, and providing theoretical basis for the improvement and positive design of power electronic devices in power system. The gate driver is based on field programmable gate array, which integrates pulse control, drive and protection, signal acquisition, and serial communication functions. The main functional modules are described in detail in the paper, and the functions and reliability were verified by mathematical model simulation and experiments. The paper provides a technical reserve for the digital and intelligent development of gate drive technology, and data support for the failure analysis and health management research of IGBT modules.关键词：IGBT gate driver;data acquisition;FPGA;digital gate drive;smart gate drive
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发布时间：2024-08-02 - 摘要：Aiming at the new generation of high-voltage packaged SiC device modules with smaller chip size and higher power density, this paper applied the research methods of numerical simulation and test, and studied heat transfer optimization design based on an new composite phase change cooling technology. The results of the optimized design were compared with the conventional profile fin cooling scheme with the same dimensions. The results of comparison show that the temperature rise of the new composite phase change radiator can be reduced by 23.9-32.5 K (39.7%-61.6%) compared with that of the profile fin radiator at the same wind speed with the power of 3×630 W. Under the conditions of the same air cooling system, the range of temperature rise can be reduced by 52%. Under the condition of the same design temperature rise of the radiator, the application power of a single IGBT can increase by about 860 W, or doubling the original power. It has a broad development prospect for the application of high power and high heat flux heat dissipation.关键词：new composite phase change radiator;thermal management;numerical simulation;SiC device
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发布时间：2024-08-02
High-power Devices
- 摘要：The rubber tyred metro has three-series suspension systems and two sets of running systems, namely rubber wheels and steel wheels. The steel wheels, as safety wheels, only function in the event of tyre burst and turnout passing. In normal running, the steel wheels have no contact with the rail, so the calculation formula of the flexibility coefficient of rail vehicle derived in the past is no longer applicable to the rubber tyred metro. In view of the differences between the running systems of rubber tyred metro and railway vehicle, this paper deduced the calculation formula of the flexibility coefficient of the rubber tyred metro vehicle according to the definition of the flexibility coefficient in the UIC 505-5 regulation, and established the "vehicle-tyre-track beam" coupling dynamics simulation model of the rubber tyred metro vehicle by using the multi-body dynamics software ADAMS to verify the correctness of the formula. The calculated results were close to the simulation results. When the rubber tyred metro stopped on the inclined track with a superelevation rate of 11.15% in AW5 working condition, the value of the flexibility coefficient was the maximum and exceeded the limit value of 0.4 of the flexibility coefficient provided in the UIC 505-5 regulations. However, it could be judged that the rubber tyred metro was in a safe state at this time and did not overturn according to the tyre force and wheel load reduction rate. The results show that the derived formula for calculating the flexibility coefficient is consistent with the simulation results. However, due to the obvious difference between the conventional track structure and the rubber tyred metro vehicle, it is not suitable to use the limit value of the flexibility coefficient provided in the UIC 505-5 regulation and the flexibility coefficient to evaluate the anti-overturning ability of the rubber tyred metro vehicle in the AW5 working condition.关键词：rubber tyred metro;three-series suspension;flexibility coefficient;anti-overturning;multibody dynamics;metro vehicles
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发布时间：2024-08-02 - 摘要：To address the fatigue failure of wheel tyre in train operation, improve the bearing capacity of tyres and safety of resilient wheel, a systematic study of the load-bearing characteristics and relevant influencing factors of wheel tyre was carried out combined with the structural characteristics and bearing mechanism of resilient wheel. In order to accurately analyze the stress characteristics of wheel tyre with elastic support, based on the finite element theory, a parameterized calculation model of wheel tyre load-bearing characteristics with rubber blocks discrete support was established. Then, the stress state distribution, dynamic deformation and stress amplitude of wheel tyre under different structural parameters such as wheel stiffness, wheel tyre thickness and wheel diameter were studied. The results show that the stress distribution on the inner and outer surface of the tyre shows a change trend in the shape of a “W” during operation of the wheels. The inner surface is dominated by tensile stress and the outer surface, by compressive stress. With the increase of tyre thickness and wheel stiffness, the bearing capacity and safety of tyre are improved. However, when the diameter of wheel increases, the bearing capacity of tyre tends to decrease. Therefore, for the resilient wheel with bigger diameter, the wheel stiffness and tyre thickness should be appropriately increased to improve safety. The research methods and results in this paper provide not only a reliable design basis for structural and performance optimization of resilient wheels, but also a strong guidance and reference value for improving the safety and reliability of resilient wheel application.关键词：rail transit;resilient wheel;wheel tyre;load-bearing characteristics;stress;finite element
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发布时间：2024-08-02 - 摘要：Wheels are the key components of EMU and degradation occurs on wheels after long-term service, impeding the operation safety and stability of EMU. In addition, the wheels of the entire train of EMU are operated and maintained in groups, so the degradation of each wheel has overall synchronization and individual differences, and adjacent wheels affect each other in the operation and maintenance (O&M) processes. Wheel degradation is characterized by diverse influencing factors, mutual influence of parameters and high randomness, so a numerical simulation method was proposed for the degradation of whole-train wheels of EMU in full-process O&M. A probabilistic model that incorporated the relevant factors, degradation laws and uncertainties is used to simulate the key factors in the operation and maintenance process, such as wheel wear, defects and reprofiling, and then the numerical simulation of the wheel degradation process was realized through closed-loop iteration. Then, a numerical simulation method of wheel degradation based on Monte Carlo simulation is proposed to simulate the degradation process of whole-train wheels of EMU under the influence in random links. Finally, based on the operation and maintenance data of EMU in China, modeling and simulation examples were given. The results show that the method can effectively predict the average level and uncertainties of degradation of whole-train wheels of EMU, enabling forecast of the remaining service life of wheels. The method can also be used to optimize of the overhaul limits of wheels based on the wheel operation and maintenance cost evaluation, so as to reduce the cost in the whole process of wheel operation and maintenance and improve the economy of EMU maintenance.关键词：EMU;wheel;wear;reprofiling;operation and maintenance;degradation process;numerical simulation
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发布时间：2024-08-02 - 摘要：In this paper, a levitation, guidance and propulsion integrated design was proposed for maglev trains on the principle of permanent magnet electrodynamic suspension, in which the Halbach ring permanent magnet wheels and conductor plates were tilted after clockwise rotation. Firstly, the three-dimensional force characteristics of the oblique permanent magnet wheel were analyzed with the ANSYS Maxwell finite element simulation software. According to the simulation results, for a single magnetic wheel with an outer diameter of 200 mm, the oblique angle should not be less than 60 degrees to ensure a buoyancy-weight ratio greater than 5.5 and generate a corresponding propulsive force of 310 N and guiding force of 380 N. Further analysis involved the variation law of the three-dimensional force of the magnetic wheel with the working air gap, conductor plate thickness and conductivity. The three-dimensional force decreased with increasing working air gap. With the increase of the thickness and conductivity of the conductor plate, the suspension force and guiding force increased until reaching saturation, while the propulsion force increased first and then decreased. Based on the above analysis results, a new conceptual model of the levitation, guiding and propulsion integration was presented for maglev trains, and the magnetic wheels with larger diameters and widths were calculated and analyzed. According to the results, the magnetic field utilization rate is the maximum when the diameter is 250 mm in diameter, and the utilization rate is positively correlated with the change in the magnetic wheel width. Applying and extending the permanent magnet electrodynamic suspension theory, the study results can be applied to effectively reduce the construction cost of maglev train systems and provide a reference for the design of new maglev trains with integrated levitation, guidance and propulsion.关键词：permanent magnet wheel;integration;maglev train;utilization rate of EDW
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发布时间：2024-08-02 - 摘要：Based on the two test tracks which CRRC Ziyang Locomotive Co., Ltd. participated in the construction, this paper introduces the design principles, grounds for parameter selection, general implementation plan, and implementation of key subsystems including bogie, electrical control system, braking system, and rescue equipment during the development of the suspended monorail train. In addition, the paper analyzes the test data of key performance such as the smoothness, posture and noise of a running train. The paper also describes the problems occurred during the test and state of train in detail, with the analysis of problem cause and introduction to the process of identifying the optimal structure and parameters of related equipment after step-by-step improvement and optimization. Relevant experience can provide reference for the design and development of similar products in the future.关键词：suspended monorail train;type selection;development;test;urban rail transit
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发布时间：2024-08-02
Railway Rolling Stock
- 摘要：The rolling bearing is an important part of the traction motor of high-speed train, and its failure seriously affects the safety of train operation. The acoustic diagnosis method for bearing fault has the advantages of non-invasive installation and low operation and maintenance cost, but it also has the disadvantages of low signal-to-noise ratio and difficult to extract fault features. Machine learning has the robustness to avoid the influence of noise. Aiming at the problem that a small number of features cannot fully characterize the bearing fault when applying machine learning to acoustic fault diagnosis, this paper proposes to superimpose and fuse the Gramian angular field (GAF) and wavelet time-frequency figure to form a six channel fusion feature map to effectively characterize the bearing fault. Firstly, the traction motor bearing acoustic fault test-bed was established to obtain the fault acoustic signal. Secondly, the acoustic signal fusion feature map based on GAF was established. Then, the residual networks (ResNETs) model was used to train and verify the fault classification model for the features of the fusion feature map, and the accuracy was compared with the fault classification method with a single feature map as the feature. The results show that the acoustic fault classification model based on GAF fusion feature map has an accuracy of 99.89%, so the fusion feature map can more effectively reflect the bearing fault.关键词：traction motor bearing;acoustic fault diagnosis;convolutional neural network;fusion feature map;Gramian angular field;high-speed train
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发布时间：2024-08-02 - 摘要：A large amount of measurement noise exists in the gap sensor signals of the suspension system of maglev train, which affects the control quality and stability of the suspension system. To address this issue, the boundary curve of the second-order discrete time optimal control was determined by means of isochronous region, and a new form of discrete time optimal control function, without complicated square root operation, was constructed based on the boundary curve and the reachable region. The phase compensation was achieved by differential prediction compensation method. Then, the suspension controller based on the new tracking differentiator (TD) was designed. The numerical simulation shows that the TD can quickly track the input signal with favorable filtering effect, no chattering and overshoots. The experiments conducted on the maglev train platform demonstrate that the proposed suspension controller of TD can significantly reduce the maximum overshoots around 15% during the levitation of the train and achieve stable suspension control of the maglev train, indicating strong engineering practicability.关键词：maglev train;suspension control;gap signal;tracking differentiator;phase compensation;simulation
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发布时间：2024-08-02 - 摘要：In order to solve the influence of high reactive power, negative sequence current and harmonic distortion rate on power quality in railway traction power supply system, multi-dimensional Taylor network optimization control was applied to railway power conditioner with modular multilevel converter (MMC-RPC). Compared with traditional double closed-loop PI controller, multi-dimensional Taylor network (MTN) controller has advantages of strong anti-disturbance ability, better robustness and lower harmonic distortion rate. Aiming at the parameter setting problem, the integral of the error square between the reference value and the actual value of the dq axis current was used as the output performance index, and the particle swarm optimization algorithm was used to optimize the parameters in MTN. In MATLAB/Simulink, the simulation models of MMC-RPC using MTN controller and PI controller were built respectively, and the two common working conditions of locomotive load and load mutation were compared in electrified railway, which verified the effectiveness and superiority of MTN controller in MMC-RPC.关键词：railway static power conditioner;modular multilevel converter;multi-dimensional Taylor network controller;particle swarm optimization
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发布时间：2024-08-02 - 摘要：Accurate positioning of trains is of great importance to the safety of train operation. In some foreign subway projects, limited by the maturity of technical system and control of design cost, conventional GPS and CBTC positioning technologies cannot meet the demand of train positioning in the projects. Therefore, a nonlinear compensation based self-positioning method for rail transit trains is proposed. This method can achieve precise positioning of trains solely relying on existing onboard equipment without adding new equipment such as GPS, CBTC, etc. The proposed method features simple composition, low cost, high accuracy, and high reliability (free from environmental affection), which is worth further promotion. Firstly, the specific process used neural networks to establish a compensation model for the instantaneous speed of trains and improve the accuracy of train instantaneous speed through the compensation model, and then the real-time running distance of the train was obtained by integrating the compensated real-time speed and operating time of the train. Afterwards, the distance of the train to the next station was calculated based on the fixed train operation diagram, thus to realize positioning. The experimental results show that after compensation the positioning accuracy is less than 0.2 m, upgraded by 3-4 times of the accuracy before compensation.关键词：rail transit;train positioning;neural network;nonlinear compensation
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发布时间：2024-08-02
Electric Traction and Control
- 摘要：In urban rail transit, in addition to overhead catenary system, the electric shoegear-conductor rail system is often used for energy supply of trains. In the shoegear-conductor rail system, the electric shoegear slides along the conductor rail, and the vibration behavior is complex and vulnerable to the influence of line conditions and the structure itself. When the conductor rail has rail joint gap, the shoegear passing through will generate large impact force, resulting in the deterioration of the current collection quality of the shoegear-conductor rail system. Based on multi-body dynamics and finite element theory, this paper built a shoegear-conductor rail coupling dynamics model, and compared it with measured data to verify the accuracy of the model. Based on the model, the dynamic performance of the shoegear-conductor rail system at different speeds and with rail joint gaps in different directions was analyzed, considering the worst conductor rail joint gap conditions specified in the standard. The results show that when the shoegear passes through the front-high-rear-low rail joint gaps, the vehicle running speed has a more serious influence on the current collection quality of the shoegear-conductor rail system compared to the front-low-rear-high rail joint gaps.关键词：urban rail transit;shoegear-conductor rail system;rail joint gap;current collection quality;multi-body dynamics method
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发布时间：2024-08-02 - 摘要：In order to ensure the power quality of traction power supply system and reduce the costs for purchasing electricity by traction substation, a probabilistic forecasting model of traction load based on sparse Gaussian process (SGP) is proposed. Firstly, the model constructed the input feature vector based on the historical characteristics of traction load and time information. Then, the mapping relationship between input characteristics and traction load was established, and SGP was used to fit the mapping relationship. Finally, a rolling forecasting methodology was used to predict the traction load. The comparative experiments carried out on the real operation data of a traction substation on Shuohuang railway verify the advantage of the proposed method, where the point forecasting can obtain the prediction value with an error of about 7%, and the probabilistic forecasting can obtain the reliable prediction interval under different confidence coefficients.关键词：ttraction load;load forecasting;Gaussian process;point forecasting;probabilistic forecasting;electric locomotive
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发布时间：2024-08-02 - 摘要：A grounding method of OCS pillar foundation based on conductive concrete was proposed to solve the grounding problem of traction power supply system in areas with high soil resistivity. The proportioning of materials for conductive concrete was optimized from two aspects: mechanical strength and conductivity, and the composite conductive material composed of 20% graphite + 2.5% steel fiber was selected. By analyzing the natural grounding scheme and effect of conductive concrete OCS pillar foundation, it was found that scheme could reduce the grounding resistance by 73.16%. If the adjacent foundations were connected, it could meet the requirements of grounding resistance of traction power supply system. The electrothermal characteristics of conductive concrete foundation under lightning impulse were analyzed, and it was found that the temperature rise of conductive concrete OCS pillar foundation was small. The internal temperature distribution was uniform, and it was not easy to be affected by structural stress. The proposed grounding method of traction power supply system based on conductive concrete only needs to replace the ordinary concrete with conductive concrete during construction, which is simple and convenient to implement. It provides a new method for the grounding of electrified railway in areas with high soil resistivity.关键词：traction power supply;grounding resistance;conductive concrete;OCS;pillar foundation
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发布时间：2024-08-02
Railway Electrification
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