最新刊期
卷 ， 期 4 ， 2023
- 摘要：Compared to traditional transportation methods, high-speed maglev trains have many advantages. On a world-wide scale, two modes of maglev systems, electromagnetic suspension (EMS) and electrodynamic suspension (EDS), have emerged mature through years of research and practice. The superconducting (SC) EDS system has potential applications for high-speed and ultra high-speed transportation, with simple system topology, high reliability, better floating to weight ratio, larger suspension gap, and self-stable characteristics of the suspension system. This paper outlines the research progress of electrodynamic suspension technology in Japan, South Korea, the United States, and China, and provides a detailed introduction to the full elements test system of high-temperature SC EDS developed by CRRC Changchun Railway Vehicles Co., Ltd. The construction of this test system promotes the research of key technologies and verification of design methods in SC EDS. Currently, the SC EDS train is still in the exploration and initial stage of engineering verification, and it requires the attention and expansion of research institutions, in order to solve the research and development problems related to key components, supporting equipment, and test tracks. In the future, maglev technology will develop towards higher speeds, better economical, and more practical technological directions.关键词：maglev transportation;electrodynamic suspension;superconducting maglev;full elements;test system
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发布时间：2024-08-02
Special Report
- 摘要：The maximum correlated kurtosis feature mode decomposition (MCKFMD) method can effectively remove redundant information and enhance fault features, but its effect is affected by the number of decomposition modes, the number of initialized filters and the filter length. To address this problem, a bearing fault diagnosis method based on compound Gini index (CGI) and MCKFMD was proposed. Firstly, a new sparse index called CGI was constructed by combining the squared Gini index in the time domain and frequency domain to quantify the abundance of periodic impulses in the time domain and frequency domain, and its performance was evaluated and verified. Secondly, CGI was used as the fitness function for the sand cat swarm optimization (SCSO) algorithm to quickly and accurately obtain the optimal parameter combination of MCKFMD and realize the adaptive decomposition of fault signals. Finally, CGI was used to select the optimal mode for Hilbert envelope demodulation to achieve fault feature extraction. The proposed method was verified for effectiveness by using analog and experimental signals, and comparative studies have shown that it is more effective in extracting periodic fault features compared with the parameter-optimized variational modal decomposition (VMD) and fixed-parameter MCKFMD.关键词：maximum correlated kurtosis feature mode decomposition;sand cat swarm optimization algorithm;fault diagnosis;bearing faults;compound Gini index;EMU
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发布时间：2024-08-02 - 摘要：A rolling contact fatigue prediction model and a wear prediction model were established to analyze the influence of slope and speed on the rolling contact fatigue and wear of electric multiple unit (EMU) wheels on long steep slope track. The wheel rolling contact fatigue prediction model was composed of a vehicle dynamics model and a damage function. The wheel wear prediction model included a vehicle dynamics model, a wheel-rail local contact model, a wear model, and smoothing and updating strategy. The wheel wear prediction model was modified and verified based on the field measured wheel wear results. The results show that downhill is the main case of wheel rolling contact fatigue, and the higher the speed or downhill slope, the more likely the wheel initiate rolling contact fatigue. When the vehicle runs in a straight line, the fatigue crack initiation position is basically within the range of 6 to 9 mm from the outside of the nominal rolling circle of the wheel, and the fatigue crack initiation angle is basically between -10° to10°. Whether uphill or downhill, the greater the slope, the greater the wheel wear. The wear area of the wheels on an uphill condition with a slope of 30‰ is approximately 1.85 times that of a downhill condition with a slope of ‒30‰. Under the same slope conditions, for uphill cases, wheel wear increases with the increase of vehicle speed; for downhill cases, vehicle speed has less effect on wheel wear.关键词：long steep slope;electric multiple unit;wheel rolling contact fatigue;wheel wear prediction;wear model;high-speed railway
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发布时间：2024-08-02 - 摘要：As the axle assembly relationship of variable gauge bogie is clearance fit, in which the axle box bearing bears greater axial load compared with the traditional bogie axle box bearing, it is necessary to consider the impact of axial load on bearing contact stress. A simulation model of a 1 435/1 520 mm high-speed variable gauge bogie axle bearings was established using Romax, and the impact of different track gauges, different roller modification methods, and different axial clearance on the contact stress between the rollers and the inner ring were analyzed when considering axial load. The calculation results show that: After the bearing is subjected to axial load, 1) the bearing contact stress is more serious in case of broad gauge than standard gauge, and the maximum contact stress of unmodified roller does not meet the standard requirements; 2) the 4 types of modified rollers can reduce the maximum contact stress and stress concentration coefficient compared with the unmodified rollers, among which the ability of logarithmic modified rollers to bear axial load is better than the other 3 types of modified rollers; and 3) the optimal axial clearance will continue to decrease in the direction of negative clearance.关键词：axle box bearing;axial loading;contact stress;gauge;modification method;axial clearance;high-speed train
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发布时间：2024-08-02 - 摘要：Regarding the contact problem of axle sleeve type spline pair in the wheel axle structure of 1 435 mm/1 520 mm gauge-changeable bogie with a speed of 400 kilometers per hour, the contact pressure distribution was studied under different gauge and misalignment angles, and the influence of crowned modification and gear tip rounding on the contact pressure distribution on the tooth surface of spline pair was studied in the paper with ABAQUS software. The calculation results show that: the maximum contact pressure on the tooth surface of the spline pair increases with the increase of misalignment angle, and the contact pressure on the broad gauge is greater than that on the standard gauge; when there is angular misalignment, crowned modification significantly reduces the maximum contact pressure of the spline, as the amount of modification quantity increases, the compensation ability of the spline for angular misalignment becomes stronger; the crowned shaped axle sleeve type spline pair has an misalignment angle range, which causes the maximum contact pressure of the spline pair to be smaller on the broad gauge than on the standard gauge, and the angle range increases as the amount of modification quantity increases; the edge effects in the direction of tooth profile is improved after the crowned shaped axle sleeve type spline pair is rounded at the gear top, further reducing the maximum contact pressure.关键词：gauge-changeable technology;spline pair;misalignment angle;crowned modification;gear tip rounding;high-speed EMU
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发布时间：2024-08-02 - 摘要：This paper first introduced the principle and process of modeling turnouts by the multi-body dynamics software Simpack, and then expounded the process to solve the wheel-rail contact geometric relationship in the turnout area using the trajectory method programmed by MATLAB and based on the measured data of No. 12 speeding-up turnout profile and JM3 tread, and accordingly revealed the distribution of wheel-rail contact points in different turnout areas as the study results. A vehicle-turnout dynamic interaction model was first established by Simpack in the current study according to the characteristics of 160 km/h railway vehicles, to simulate the dynamic response of the vehicle passing through turnouts at 160 km/h directly and inversely before and after the tread wear, and to discuss the impact of the stiffness and damping of the vehicle's lateral damper and anti-hunting damper on the hunting motion in the turnout area. The results show that the continuous changes of wheel-rail contact geometry in the turnout area is an important factor affecting the dynamic performance of the turnout area. To be specific, when the vehicle passes through turnouts with discontinuous wheel-rail contact points, the wheel-rail coupling is vulnerable to impact, which is mainly represented by the vertical impact and vibration at the frog, and any sudden change of the contact points also causes lateral vibration. The vehicle with over-worn treads suffers from the hunting motion when passing through turnouts at a high speed, which can be suppressed by adjusting the parameters of the anti-hunting damper and lateral damper, as a move to improve the dynamic performance of the vehicle passing through turnouts.关键词：railway vehicle;variable-section turnout;wheel-rail contact geometry;dynamic performance
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发布时间：2024-08-02 - 摘要：During train operation, influenced by track irregularity or random wind load, the vehicle body is continuously under the impact of random vibration loads, which will cause fatigue damage to the vehicle structure in severe cases. To ensure train operation safety, an analysis of random vibration fatigue of the door on a new 160 km/h large volume box wagon with movable side walls was carried out. Considering the influence of excitation transmission on bogie, car body and other parts, the vehicle body dynamics simulation model was established through a flexible modeling method, and the door's vertical vibration acceleration spectrum was obtained by using the American sixth grade track line. The door's fatigue damage was calculated with two analyzing methods, which were the frequency domain analysis based on the stress response power spectrum density function and the time domain analysis based on the rain flow counting method. The results show that the door's fatigue life under the two analyzing methods both meet the requirements for operating six million kilometers, and the areas with weak fatigue strength are welding parts on the door seat. The fatigue damage calculated by frequency domain analysis method is 0.89, and that calculated by time domain analysis method is 0.51. The former is more conservative. Finally, the reasons for the difference between the two results are analyzed from three angles, namely the data processing methods, evaluation methods and calculation principles.关键词：160 km/h box wagon;fatigue life;random vibration;flexible modeling;time domain analysis;frequency domain analysis;simulation;track irregularity
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发布时间：2024-08-02 - 摘要：In view of the significant difference between maglev train and wheel-rail train on the vibration environment of on-board equipment, for the accelerated vibration test of maglev equipment, the whole vehicle vibration test of commercial maglev version 3.0 train was carried out on the high-speed maglev test line of Tongji University. According to the measured PSD obtained by the statistical tolerance method, the acceleration factor was deduced to be 5.66. Based on this, the accelerated vibration test profiles in x, y and z directions of the maglev equipment were designed. The comparison between the measured PSD and the standard PSD in IEC 61373:2010 shows that the magnitude of the measured PSD is lower than that of the standard PSD in the frequency band of 2~50 Hz, the relative deviation of the RMS values between the two is -35.3% to -59.4%, the upper limit of vibration frequency of the measured PSD is 500 Hz, higher than that of the standard PSD, which is 150 Hz. It can be seen that the magnitude of vibration of maglev equipment is lower than that of wheel-rail train, but with a wider vibration frequency band range than standard requirement. Therefore, using the measured PSD can more truly simulate the operating vibration environment of maglev equipment.关键词：maglev train;accelerated vibration test;measured data;data induction
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发布时间：2024-08-02
Railway Rolling Stock
- 摘要：In order to promote scientific and technological innovation in the field of high-speed railway equipment, a new generation of 400 km/h EMU is attempted to create, which is faster, safer, more environment-friendly, energy-saving, intelligent. Based on the traction requirements of high-speed EMU, considering the indexes of wheel-rail adhesion and traction acceleration, this paper calculated the wheel rim power and power unit configuration of high-speed EMU with a speed of 400 km/h. Based on the design idea of traction system simplification and design platform of traction system of EMU based on Chinese standards, the technical parameters and traction main circuit topology design scheme of the new generation of high-speed EMU permanent magnet traction system were proposed, and the network-side characteristics and inverter output characteristics of the traction system were simulated and verified. Combined with the characteristics of permanent magnet traction system, the key technologies such as high-speed permanent magnet motor with restarting at unknown speed, permanent magnet motor rotor position angle identification and early warning for loss of excitation were analyzed and verified. The results have guiding significance for the research and development of high-speed EMU permanent magnet traction system.关键词：high speed EMU;permanent magnet traction system;traction converter;main circuit
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发布时间：2024-08-02 - 摘要：Heavy-haul trains need to be braked in cycles when running on long and steep downslopes, which causes great challenges for drivers and brings huge influences to the safe and smooth operation of the trains. In the current study, a multi-objective optimal operation model was established for heavy-haul trains firstly, considering the dynamic process in the application of air braking force, and the constraints due to the train operation environment and vehicle mechanical characteristics, and then was solved by the quadratic programming algorithm. Since the air braking model can hardly be linearly approximated, the air braking force was incorporated into the optimization model as a kind of train known control force, taking advantage of the consistent main characteristics of the modeled speed curve, resulting in the electro-pneumatic braking control decoupled spatially and temporally. Moreover, an iterative algorithm was designed to fit the air braking force with the optimized speed curve. Finally, the operation criteria for heavy-haul trains on long and steep downslopes were quantified and incorporated into the model as the specific constraints parameters for simulative study, and the results were compared with the measured operation data. The comparison results demonstrate that the proposed algorithm can achieve safe and steady operation of heavy haul trains by reducing coupler force.关键词：heavy-haul train;model-based operation;quadratic programming;iterative algorithm;longitudinal impulse
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发布时间：2024-08-02 - 摘要：The paper provided a brief introduction to the characteristics and current applications of permanent magnet synchronous motors in the trains of Changsha metro line 5. It selected an experimental train that used a permanent magnet synchronous traction system on Changsha metro line 1 to conduct line simulation and on-site energy-saving tests for the traction system's energy consumption. Based on the analysis of the no-load energy consumption of trains using asynchronous traction systems on lines 1–4 and trains using permanent magnet synchronous traction systems on line 5 of Changsha metro, the efficiency and energy consumption with trains using asynchronous traction systems were compared and analyzed in detail. It was found that for the lines with regenerative energy absorption and utilization devices installed on the overhead contact network of the main track, excluding the impact of passenger capacity, the average energy saving rate of no-load trains on line 5 was 29.56% compared to line 1, line 3, and line 4, and 39.21% compared to line 2 without the regenerative energy absorption and utilization devices installed on the overhead contact network of the main track. Energy consumption of the train is an important part of the operation cost. The permanent magnet traction system has obvious energy-saving effect, which is consistent with the national requirements for the development of energy-saving, low-carbon economy. The application of permanent magnet traction system is helpful to reduce the operating cost of metro trains and realize the goal of rapid green transportation.关键词：metro;permanent magnet traction system;permanent magnet synchronous motor;energy consumption of no-load trains;energy consumption analysis, energy-saving;simulation
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发布时间：2024-08-02
Electric Traction and Control
- 摘要：Arcing on metro pantographs contribute to the accelerated wear of pantograph strips and the catenary, imposing a serious safety risk to rail transit. For the problem of strong light interference and variable background in pantograph arcing detection for metro vehicles, an arcing detection method based on an improved yolov4-tiny model is proposed. In order to improve the detection ability of small targets, this method incorporated a third-scale prediction branch to the original two-scale prediction branches of yolov4-tiny, to enable the positioning of small arcs in the shallow network. Moreover, a receptive field block (RFB) module was embedded beneath the backbone network, to expand the network′s receptive field and enhance the model′s feature extraction ability. The test results show the average precision (PAP) of the improved model on the test set is increased to 98.2%, marking an improvement of 7.8 percentage points over yolov4-tiny. Despite yielding similar positioning effect for arcs, the improved model works at significantly higher speeds than yolov4, enabling inference speed of a single image in only 6.5 ms. The proposed method is proven effective and accurate in fulfilling the arcing detection task for pantographs of metro vehicles.关键词：metro vehicle;arcing detection;target detection;YOLO;deep learning
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发布时间：2024-08-02 - 摘要：Aiming at the problems of inaccurate extraction, discontinuity and being susceptible to noise when the edge of a carbon slide is detected by using a traditional edge detection algorithm, an edge detection method of pantograph carbon slide based on an improved Canny algorithm was proposed in the paper. Firstly, the cascade filter with a combination of anisotropic diffusion and bilateral filter was used instead of the Gaussian filter in the original algorithm to denoise the image and improved the algorithm's ability to smooth various mixed noises. Gamma transformation was used to highlight the edge features of the image. Scharr operator was used to determine the gradient magnitude of the edges. Otsu algorithm was introduced to overcome the drawback of manually setting the high and low thresholds in the original algorithm, making the algorithm have better adaptability in determining the dual thresholds. Finally, the edge contour was further improved with morphological ideas and the Zhang-Suen refinement algorithm to eliminate possible subtle voids in the edges. The experimental results show that the improved algorithm can extract the edge information of the carbon slide more accurately than the traditional algorithm, and has strong adaptability and anti-interference, which provides effective theoretical support for the subsequent detection of the pantograph carbon slides.关键词：pantograph carbon slide;Canny algorithm;cascaded filter;Scharr operator;Otsu algorithm;Zhang-Suen refinement
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发布时间：2024-08-02 - 摘要：In order to solve the power quality issue caused by dominant negative sequences, which result from single-phase loads of electrified railways in the three-phase grids, this paper presented a control strategy of compensation for negative sequences particularly suitable for electrified railways, taking the super-capacitor integrated modular multilevel converter (SC-MMC) system as the object, and leveraging precise compensation of negative sequence current by converters and efficient utilization of regenerative braking energy through energy storage facilities as the regulation means. Aimed to improve system reliability and flexibility, the MMC sub-modules were connected with super-capacitor storage devices in a decentralized pattern, to coordinate the MMC and energy storage devices for joint negative sequence compensation. This study began with an analysis of the working theory of the energy storage modular multilevel system, based on the main circuit topology and negative sequence compensation principle. Then, a system mathematical model was constructed based on a single-phase equivalent circuit and working modes were divided into charging, discharging, and balancing, taking into account the locomotive load characteristics and super-capacitor state of charge (SOC). Finally, a hierarchical coordinated control strategy was proposed, among which energy management is designed at the upper layer to identify working modes and calculate reference power for each port within the limits specified in relevant national standards, while port current control was designed at the lower layer to enable power tracking for each port and dynamic switching coordination between different operating modes. The case study shows the effectiveness of the SC-MMC system in compensating for negative sequences in the grid under different locomotive load levels and super-capacitor SOC scenarios, and coordinated control of the super-capacitor and MMC to contribute to compensation.关键词：super-capacitor energy storage system;modular multilevel converter;power quality;hierarchical coordinated control
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发布时间：2024-08-02 - 摘要：In order to study the influence of stray current from urban rail transit systems in dynamic operation on the magnetic bias characteristics of substations along the line, simulation analysis was conducted in the current study, with a coupled simulation model of "rail transit system - substation AC power grid" established by CDEGS software based on a 220 kV substation in Shanghai and its nearby rail transit system, across a complete metro train running cycle of "starting-coasting-braking-stopping", involving the potential and current variation rules of each structural level, the spatial distribution of stray current and the bias DC of the transformer neutral point. Comparison was then made between the simulation results and the field test data. Based on the results, in this simulation model, the rail potential is low only when the traction substation supplies power to trains, with little effect on the bias DC of the transformer neutral point; the rail potential greatly increases when power is supplied across sections for train braking, up to 25.424 V, and the bias DC of the transformer neutral point can reach 1.2 A; the total rail leakage current peaks, i.e. 21.647 A, after train operation for 105 s, while it is 17.908 A at 12 s after train starting; the highest proportion of inflow to the transformer neutral point is 3.473%. During a complete train running cycle, the rail potential in some rail sections alternates between positive and negative, which may cause bias DC reversing of the transformer neutral point.关键词：stray current;bias DC;coupled simulation model;train running cycle;cross-section power supply;urban rail transit
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发布时间：2024-08-02 - 摘要：The electrified railway catenary generates wind deflection and vibration under wind load. The longitudinal wind deflection affects the current collection quality of the contact wire and the pantograph, and causes contact force fluctuations and pantograph-catenary separation fault. The lateral wind deflection increases the contact area of the pantograph’s sliding strip, and in severe cases, the contact line is off-line laterally, resulting in pantograph scraping accidents. This paper conducted an in-depth research on the wind deflection characteristics of catenary systems in strong wind areas, and proposed a calculation method for catenary wind deflection based on nonlinear finite element to provide guidance for catenary design and wind deflection prevention. The specific methods are as follows: Considering the irregular shape of the contact wire cross-section, a hydrodynamic calculation model of the contact wire cross-section was constructed in Fluent, and the aerodynamic coefficients of the contact wire under different attack angles were obtained through the flow simulation. The static wind load model of the contact wire and the messenger wire was deduced by fluid induced vibration theory, based on a comprehensive consideration of the geometric nonlinearity of the catenary when the wind deflection occurs, the global stiffness matrix of the catenary was deduced using the absolute nodal coordinate method, and the three-dimensional nonlinear finite element model of the catenary was established. The wind deflection of the contact wire under the static wind load of different wind speeds and different initial wind attack angles was obtained by applying wind loads. Taking the actual catenary data as an example, the calculation results show that under different wind speeds and initial attack angles, the contact wire wind deflection generated by the static wind load on the catenary is affected by its aerodynamic coefficient, and increases with the wind speed. It is also very sensitive to the wind attack angle . When the wind speed is 30 m/s, the maximum lateral wind deflection of the catenary can reach 8.3% of the daily working length of the pantograph strip, which may lead to the occurrence of pantograph scraping accidents.关键词：high-speed railway;catenary;finite element;three-dimensional model;CFD;wind deflection
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发布时间：2024-08-02 - 摘要：Pantograph-catenary system is the central system for the power supply of urban rail transit trains. Higher train speed and complex train operating environment can generate severe vibrations on the pantograph-catenary system, resulting in high-frequency arcing and abnormal abrasion of pantograph. Taking the abnormal abrasion of the pantograph-catenary system in a metro project as an example, this paper studies the relationship between operation indicators and the abnormal abrasion of pantograph-catenary system, and correlations among the operation indicators. Firstly, this paper proposed the selection of indicators influencing the abnormal abrasion of pantograph-catenary system based on the definition of status indicator of pantograph-catenary operation and calculation formula. The data collection system of the metro line was established to obtain the measured data in the operation of the metro. Secondly, this paper statistically analyzed the distribution law and change trend of the indicators of old and new sliders under different working conditions, and studied the correlation among the indicators. Finally, under the same working condition, spatiotemporal dimension association analysis was used to analyze the internal connections and differences of each indicator in terms of space and time. The research results show that: in the early stage of running-in between the slider and the catenary, the arcing rate increases due to the lack of an oxide layer, which leads to an increase in the arcing rate of the pantograph-catenary contact, but the change trend between the indicators is not obvious. As the slider runs to a stable abrasion period, there is a strong correlation between the offline rate of the pantograph, arcing rate, and abnormal rate of the hard point. When one of the indicators is abnormal, it is always accompanied by the abnormality of the other indicators. The occurrence of abnormal abrasion is often accompanied by the abnormality of pantograph-catenary operation indicators. The monitoring and prevention of abnormal abrasion of pantograph-catenary can be completed by monitoring operation parameters, which provides an effective method for studying the mechanism of abnormal abrasion of pantograph-catenary.关键词：urban rail transit;train;pantograph-catenary system;abrasion;arcing;pull-out value;metro vehicle
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发布时间：2024-08-02 -
Research on on-track adaptability trial of pantograph carbon contact strips for electric locomotives
摘要：As one of consumable parts for railway electric locomotives, pantograph carbon contact strips are largely demanded, and more manufacturers engage in the trial production of pantograph carbon contact strips for electric locomotives. The current study is necessary in order to improve on-track trial operation of pantograph carbon contact strips for locomotives in the trial production stage. This paper summarized and analyzed the potential failure modes and corresponding causes of the carbon contact strips in service, expounded the necessity of the on-track adaptability trial for them, and summarized the preconditions of the on-track trial operation. In addition, an on-track adaptability trial scheme of pantograph carbon contact strips for locomotives was designed, covering five aspects of loading quantity and cycle of trial operation, tracking and monitoring during trial operation, disassembly and inspection after trial operation, evaluation of trial results and safety emergency plan. This scheme was applied to a new type of pantograph carbon contact strips for locomotives produced by a domestic manufacturer. The on-track trial process and test data comprehensively proved the feasibility of this trial scheme, not involving any effect to the normal operational service of the locomotive. The trial scheme can fully reflect and evaluate the adaptability and quality reliability in the on-track application of new locomotive pantograph carbon contact strips in trial production, and effectively guide the relevant parties in the actual operation of the pantograph carbon contact strips for locomotives on the trial site, thus reducing the safety risk of the on-track trial, and provide important technical support for the mass loading of pantograph carbon contact strips on locomotives.关键词：electric locomotive;carbon contact strip;adaptability;trial scheme- 43
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发布时间：2024-08-02
Railway Electrification
- 摘要：Based on the phase change isothermal technology for deep hole drilling machine, a research methodology involving numerical simulation and experimental testing was applied to optimize the heat transfer design of a heat sink for a rail transit project with non-uniform heat flux density and multiple integrated heat source devices in its thermophysical field. First of all, a comparison was made on the temperature rise performance of heat sinks with phase change isothermal technology for deep hole drilling machine in different installation directions, the fluctuation range under different working conditions is only 1.6%-3.4%, showing a small difference, indicating that the heat transfer process of the working medium inside the heat sinks with phase change isothermal technology for deep hole drilling machine had good anti-gravity characteristics. Secondly, the performance of the newly designed and optimized heat sinks with phase change isothermal technology for deep hole drilling machine was compared with that of the conventional finned heat sink of the same size. The results show that the temperature rise of heat sinks with phase change isothermal technology for deep hole drilling machine can be reduced by 6.0-14.3 K, with a reduction rate of 10.9%-13.8%, compared with conventional finned heat sink under the same working conditions. The maximum reduction in the average temperature is 26.3 K, with a maximum reduction rate of 53.3%, and both the temperature rise control and the average temperature are greatly improved, indicating that the application of phase change isothermal technology for heat dissipation of deep hole drilling machine in thermophysical fields with non-uniform heat flux density and multiple integrated heat source devices can yield significant heat dissipation advantages.关键词：heat sinks with phase change isothermal technology for deep hole drilling machine;temperature uniformity;numerical simulation;temperature rise comparison
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发布时间：2024-08-02 -
Intelligent integrated power device with high power density and research on its parallel application
摘要：To overcome the limitations on the packaging and application structure of traditional power semiconductor devices and upgrade converters, this paper proposed a novel intelligent integrated power device with high power density. Its feasibility was investigated by focusing on common parallel application scenarios in the high-power converter field. The study primarily examined the four key influencing factors: device parameters, main circuit, heat dissipation structure, and drive control. It analyzed and validated the excellent device matching, inductance balance, heat dissipation uniformity, control signal synchronization, and anti-interference capability. Subsequently, the article demonstrated the favorable parallel current sharing effect through the double pulse test and power assessment test. The experimental results show the achievement of the theoretical design and physical verification objectives of this technology platform, establishing a strong foundation for future engineering applications.关键词：high power;high voltage;integration;intelligent;IGBT;IPM;paralleled current sharing- 56
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发布时间：2024-08-02 - 摘要：To meet the high requirements for performance and reliability in packaging silicon carbide (SiC) power devices, this paper focused on studying relevant advanced interconnection processes, specifically double-side silver sintering technology for chip and thick copper wire ultrasonic bonding technology. Through a series of quality evaluations and tests, a comparative analysis was conducted regarding the influence of different sintering processes on double-side silver sintering layers for chip and chip shear strength, and the effect of lining plate surface materials on copper wire bonding strength. In addition, temperature shock tests were conducted on the samples, to investigate the influence of temperature shock on silver sintering in terms of microstructure and shear strength, as well as the copper wire bonding strength. The experimental results show that both the single-sintering process and multiple-sintering process achieve chip shear strength standard values that meet industrial production requirements, but the multiple-sintering process exhibits superior silver sintering effects in terms of structure and chip shear strength. Under temperature shock conditions, the sintering silver displays expanded necks and pores in the microstructure, and both sintering processes produce a significant increase in chip shear strength. Moreover, the choice of lining plate material significantly influences the copper wire ultrasonic bonding strength. Although bonds on bare copper active metal braze (AMB) exhibit better mechanical properties compared to silver-plated AMB, the former deteriorates in mechanical properties under the effect of temperature shock, while the mechanical properties of the latter are enhanced. Taking into account the fracture modes shown at the second bond after the pull test, temperature shock contributes to shifting the fracture mode of bonds on bare copper AMB from 100% neck fracture to welding spot drop, while a gradual decrease in welding spot drop for silver-plated AMB.关键词：silicon carbide power device;double-side silver sintering for chip;cooper wire bonding
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发布时间：2024-08-02
High-power Devices
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