The regenerative braking energy utilization system(RBEUS)stands as a promising technique for improving the efficiency and power quality of electrified railways.Beyond the vital aspects of energy management and control...The regenerative braking energy utilization system(RBEUS)stands as a promising technique for improving the efficiency and power quality of electrified railways.Beyond the vital aspects of energy management and control strategies,ensuring fault protection is paramount for the secure and steady operation of the traction power supply system(TPSS)integrated with RBEUS.This paper introduces an innovative protection scheme tailored to diverse RBEUS application scenarios.Firstly,fault categories are streamlined into three levels:system,equipment,and warning.Subsequently,a novel multi-port active power differential protection method,aligned with RBEUS operational principles,is crafted to serve as a comprehensive and sensitive main protection.Building upon this foundation,a hierarchical protection structure for RBEUS is established,addressing the intricacies and variations in fault types while boosting anti-disturbance capabilities under faulty conditions.Embracing the principle of railway-oriented safety,a collaborative RBEUS-TPSS protection scheme is put forth.Finally,through simulated scenarios encompassing various fault conditions,the proposed scheme’s feasibility and effectiveness are convincingly validated.展开更多
The cone-jet in electrohydrodynamic atomization has been widely applied into numerous industrial fields owing to micro-sized drops with narrow distribution and high charge.The electrified jet emits from a single capil...The cone-jet in electrohydrodynamic atomization has been widely applied into numerous industrial fields owing to micro-sized drops with narrow distribution and high charge.The electrified jet emits from a single capillary sheathed with quartz tube is visualized versus operating parameters and physical properties,and breakup instabilities are also discussed.The range of operating parameters for a steady conejet broadens,as well as the minimum flow rate.Taylor cone angle decreases with an increase in flow rate,while increases as electric potential increasing.The jet breakup length decreases with an increase in flow rate and conductivity,while increases as electric potential increasing.The diffusion angle increases as flow rate increasing,while decrease as electric potential and conductivity increasing.Much clearer whipping instabilities are observed with an increase in“electro-Weber”number and conductivity.The completion in disturbance or/and suppression from axial and radial stresses,drag force dominates the variation.Meanwhile,for a large flow rate,the transition from varicose instabilities to whipping instabilities is found.The whipping instabilities are clearly observed for high conductivity due to much more free ions in liquid.For much higher conductivity,an intermittent electrified jet appears and shows an umbrella plume,and breakup length sharply shortens.展开更多
Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, C...Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and CnHm of electrified railways, and analyzed their dynamic characteristics during the period of 1975 2007. The results show that during this period, the annual mean values of energy saving is 1.23×10^6 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 4.267×10^6 t, 20.5×10^3 t, 3.0×10^3 t, 9.6×10^3 t, 67.9×10^3 t, and 6.9×10^3 t per year, respectively. The annual average increasing rates of energy saving is 139×10^3 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 483×10^3 t, 2.3×10^3 t, 0.34×10^3 t, 1.1×10^3 t, 7.7 ×10^3 t and 0.78×10^3 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China＇s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China＇s railway transportation.展开更多
In order to improve the Power Quality(PQ)of traction power supply system and reduce the power rating and operation cost of compensator,a Static VAR Compensator(SVC)integrated Railway Power Conditioner(RPC)is presented...In order to improve the Power Quality(PQ)of traction power supply system and reduce the power rating and operation cost of compensator,a Static VAR Compensator(SVC)integrated Railway Power Conditioner(RPC)is presented in this paper.RPC is a widely used device in the AC electrified railway systems to enhance the PQ indices of the main network.The next generation of this equipment is Active Power Quality Compensator(APQC).The major concern of these compensators is their high kVA rating.In this paper,a hybrid technique is proposed to solve aforementioned problems.A combination of SVC as an auxiliary device is employed together with the main compensators,i.e.,RPC and APQC that leads on to the reduction of power rating of the main compensators.The use of proposed scheme will cause to reduce significantly the initial investment cost of compensation system.The main compensators are only utilized to balance active powers of two adjacent feeder sections and suppress harmonic currents.The SVCs are used to compensate reactive power and suppress the third and fifth harmonic currents.In this paper firstly,the PQ compensation procedure in AC electrified railway is analyzed step by step.Then,the control strategies for SVC and the main compensators are presented.Finally,a simulation is fulfilled using Matlab/Simulink software to verify the effectiveness and validity of the proposed scheme and compensation strategy and also demonstrate that this technique could compensate all PQ problems.展开更多
Increasing railway traffic and energy utilization issues prompt electrified railway systems to be more economical,efficient and sustainable.As regenerative braking energy in railway systems has huge potential for opti...Increasing railway traffic and energy utilization issues prompt electrified railway systems to be more economical,efficient and sustainable.As regenerative braking energy in railway systems has huge potential for optimized utilization,a lot of research has been focusing on how to use the energy efficiently and gain sustainable benefits.The energy storage system is an alternative because it not only deals with regenerative braking energy but also smooths drastic fluctuation of load power profile and optimizes energy management.In this work,we propose a co-phase traction power supply system with super capacitor(CSS_SC)for the purpose of realizing the function of energy management and power quality management in electrified railways.Besides,the coordinated control strategy is presented to match four working modes,including traction,regenerative braking,peak shaving and valley filling.A corresponding simulation model is built in MATLAB/Simulink to verify the feasibility of the proposed system under dynamic working conditions.The results demonstrate that CSS_SC is flexible to deal with four different working conditions and can realize energy saving within the allowable voltage unbalance of 0.008%in simulation in contrast to 1.3%of the standard limit.With such a control strategy,the performance of super capacitor is controlled to comply with efficiency and safety constraints.Finally,a case study demonstrates the improvement in power fluctuation with the valley-to-peak ratio reduced by 20.3%and the daily load factor increased by 17.9%.展开更多
Traction power systems(TPSs)play a vital role in the operation of electrified railways.The transformation of conventional railway TPSs to novel structures is not only a trend to promote the development of electrified ...Traction power systems(TPSs)play a vital role in the operation of electrified railways.The transformation of conventional railway TPSs to novel structures is not only a trend to promote the development of electrified railways toward high-efficiency and resilience but also an inevitable requirement to achieve carbon neutrality target.On the basis of sorting out the power supply structures of conventional AC and DC modes,this paper first reviews the characteristics of the existing TPSs,such as weak power supply flexibility and low-energy efficiency.Furthermore,the power supply structures of various TPSs for future electrified railways are described in detail,which satisfy longer distance,low-carbon,high-efficiency,high-reliability and high-quality power supply requirements.Meanwhile,the application prospects of different traction modes are discussed from both technical and economic aspects.Eventually,this paper introduces the research progress of mixed-system electrified railways and traction power supply technologies without catenary system,speculates on the future development trends and challenges of TPSs and predicts that TPSs will be based on the continuous power supply mode,employing power electronic equipment and intelligent information technology to construct a railway comprehensive energy system with renewable energy.展开更多
Purpose–The traction cable is paralleled with the existing traction network of electrified railway through transverse connecting line to form the scheme of long distance power supply for the traction network.This pap...Purpose–The traction cable is paralleled with the existing traction network of electrified railway through transverse connecting line to form the scheme of long distance power supply for the traction network.This paper aims to study the scheme composition and power supply distance(PSD)of the scheme.Design/methodology/approach–Based on the structure of parallel traction network(referred to as“cable traction network(CTN)”),the power supply modes(PSMs)are divided into cableþdirect PSM and cableþautotransformer(AT)PSM(including Japanese mode,French mode and new mode).Taking cableþJapanese AT PSM as an example,the scheme of long distance power supply for CTN under the PSMs of co-phase and out-of-phase power supply are designed.On the basis of establishing the equivalent circuit model and the chain circuit model of CTN,taking the train working voltage as the constraint condition,and based on the power flow calculation of multiple train loads,the calculation formula and process for determining the PSD of CTN are given.The impedance and PSD of CTN under the cableþAT PSM are simulated and analyzed,and a certain line is taken as an example to compare the scheme design.Findings–Results show that the equivalent impedance of CTN under the cableþAT PSM is smaller,and the PSD is about 2.5 times of that under the AT PSM,which can effectively increase the PSD and the flexibility of external power supply location.Originality/value–The research content can effectively improve the PSD of traction power supply system and has important reference value for the engineering application of the scheme.展开更多
Centrifugal microfluidic platforms are highly regarded for their potential in multiplexing and automation,as well as their wide range of applications,especially in separating blood plasma and manipulating two-phase fl...Centrifugal microfluidic platforms are highly regarded for their potential in multiplexing and automation,as well as their wide range of applications,especially in separating blood plasma and manipulating two-phase flows.However,the need to use stroboscopes or high-speed cameras for monitoring these tasks hinders the extensive use of these platforms in research and commercial settings.In this study,we introduce an innovative and cost-effective strategy for using an array of light-dependent resistors(LDRs)as optical sensors in microfluidic devices,particularly centrifugal platforms.While LDRs are attractive for their potential use as photodetectors,their bulky size frequently restricts their ability to provide high-resolution detection in microfluidic systems.Here,we use specific waveguides to direct light beams from narrow apertures onto the surface of LDRs.We integrated these LDRs into electrified Lab-on-a-Disc(eLOD)devices,with wireless connectivity to smartphones and laptops.This enables many applications,such as droplet/particle counting and velocity measurement,concentration analysis,fluidic interface detection in multiphase flows,real-time monitoring of sample volume on centrifugal platforms,and detection of blood plasma separation as an alternative to costly stroboscope devices,microscopes,and high-speed imaging.We used numerical simulations to evaluate various fluids and scenarios,which include rotation speeds of up to 50 rad/s and a range of droplet sizes.For the testbed,we used the developed eLOD device to analyze red blood cell(RBC)deformability and improve the automated detection of sickle cell anemia by monitoring differences in RBC deformability during centrifugation using the sensors’signals.In addition to sickle cell anemia,this device has the potential to facilitate low-cost automated detection of other medical conditions characterized by altered RBC deformability,such as thalassemia,malaria,and diabetes.展开更多
An overview of current thermal challenges in transport electrification is introduced in order to underpin the research developments and trends of recent thermal management techniques.Currently,explorations of intellig...An overview of current thermal challenges in transport electrification is introduced in order to underpin the research developments and trends of recent thermal management techniques.Currently,explorations of intelligent thermal management and control strategies prevail among car manufacturers in the context of climate change and global warming impacts.Therefore,major cutting-edge systematic approaches in electrified powertrain are summarized in the first place.In particular,the important role of heating,ventilation and air-condition system(HVAC)is emphasised.The trends in developing efficient HVAC system for future electrified powertrain are analysed.Then electric machine efficiency is under spotlight which could be improved by introducing new thermal management techniques and strengthening the efforts of driveline integrations.The demanded integration efforts are expected to provide better value per volume,or more power output/torque per unit with smaller form factor.Driven by demands,major thermal issues of high-power density machines are raised including the comprehensive understanding of thermal path,and multiphysics challenges are addressed whilst embedding power electronic semiconductors,non-isotropic electromagnetic materials and thermal insulation materials.Last but not least,the present review has listed several typical cooling techniques such as liquid cooling jacket,impingement/spray cooling and immersion cooling that could be applied to facilitate the development of integrated electric machine,and a mechanic-electric-thermal holistic approach is suggested at early design phase.Conclusively,a brief summary of the emerging new cooling techniques is presented and the keys to a successful integration are concluded.展开更多
Removing high-risk and persistent contaminants from water is challenging,because they typically exist at low concentrations in complex water matrices.Electrified flow-through technologies are viable to overcome the li...Removing high-risk and persistent contaminants from water is challenging,because they typically exist at low concentrations in complex water matrices.Electrified flow-through technologies are viable to overcome the limitations induced by mass transport for efficient contaminant removal.Modifying the local environment of the flow-through electrodes offers opportunities to further improve the reaction kinetics and selectivity for achieving near-complete removal of these contaminants from water.Here,we present state-of-the-art local environment modification approaches that can be incorporated into electrified flow-through technologies to intensify water treatment.We first show methods of nanospace incorporation,local geometry adjustment,and microporous structure optimization that can induce spatial confinement,enhanced local electric field,and microperiodic vortex,respectively,for local environment modification.We then discuss why local environment modification can complement the flow-through electrodes for improving the reaction rate and selectivity.Finally,we outline appropriate scenarios of intensifying electrified flow-through technologies through local environment modification for fit-for-purpose water treatment applications.展开更多
In response to the current energy and environmental challenges,reducing or replacing reliance on fossil fuels and striving for carbon neutrality seems to be the only viable choice.Recently,a cutting-edge,eco-friendly ...In response to the current energy and environmental challenges,reducing or replacing reliance on fossil fuels and striving for carbon neutrality seems to be the only viable choice.Recently,a cutting-edge,eco-friendly method of chemical synthesis via transient Joule heating(JH)demonstrated significant promise across various domains,including methane reforming,ammonia synthesis,volatile organic compounds removal,plastic recycling,the synthesis of functional carbon materials from repurposed solid waste,etc.In this review,the advantages,and latest developments in thermochemical synthesis by flash and transient JH are comprehensively outlined.Unlike the ongoing heating process of conventional furnaces that consume fossil fuels,dynamic and transient JH can get significantly higher reaction rates,energy efficiency,flexibility,and versatility.Subsequently,the transient reaction mechanism,data science optimization,and scale-up production models are discussed,and prospects for the integration of the electrified chemical industry with renewable energy for carbon neutrality and long-term energy storage are also envisioned.展开更多
The resting potential is the potential difference that exists between the inner and outer sides of the cell membrane when the cell is not stimulated.The resting membrane potential is a key regulator of phenomena such ...The resting potential is the potential difference that exists between the inner and outer sides of the cell membrane when the cell is not stimulated.The resting membrane potential is a key regulator of phenomena such as cell proliferation,morphogenesis,migration and differentiation.In this paper,we proposed a model of electrified cell clusters that considers the resting potential of cell clusters in the resting state.By measuring the potential difference between the inner and outer sides of biological tissues,it is verified that the cell cluster has a negative potential difference when taking the outer potential as the reference.In the absence of external conductors,the tissue is electrically neutral;while in the presence of external conductors,the positive net charges escape freely under repulsive forces and the biological tissues form a negative electrical equilibrium system.The model proposed in this study explored the potential situation above the cellular level in the resting state,providing a new perspective for the research on resting potential.展开更多
In the context of the“dual carbon”goals,to address issues such as high energy consumption,high costs,and low power quality in the rapid development of electrified railways,this study focused on the China Railways Hi...In the context of the“dual carbon”goals,to address issues such as high energy consumption,high costs,and low power quality in the rapid development of electrified railways,this study focused on the China Railways High-Speed 5 Electric Multiple Unit and proposed a mathematical model and capacity optimization method for an onboard energy storage system using lithium batteries and supercapacitors as storage media.Firstly,considering the electrical characteristics,weight,and volume of the storage media,a mathematical model of the energy storage system was established.Secondly,to tackle problems related to energy consumption and power quality,an energy management strategy was proposed that comprehensively considers peak shaving and valley filling and power quality by controlling the charge/discharge thresholds of the storage system.Thecapacity optimization adopted a bilevel programming model,with the series/parallel number of storage modules as variables,considering constraints imposed by the Direct Current to Direct Current converter,train load,and space.An improved Particle Swarm Optimization algorithm and linear programming solver were used to solve specific cases.The results show that the proposed onboard energy storage system can effectively achieve energy savings,reduce consumption,and improve power qualitywhile meeting the load and space limitations of the train.展开更多
The 2025 Shanghai Auto Show reaffirmed its role as one of the world’s most influential automotive industry events,offering a panoramic view of the future shaped by intelligent and electrified vehicles.With over 200 n...The 2025 Shanghai Auto Show reaffirmed its role as one of the world’s most influential automotive industry events,offering a panoramic view of the future shaped by intelligent and electrified vehicles.With over 200 new models on display-85 percent of them new energy vehicles-this year’s show spotlighted how the global auto industry is pivoting rapidly towards an era of software-defined and AI-powered mobility.展开更多
Significant advances in battery and fuel cell technologies over the past decade have catalyzed the transition toward electrified transportation systems and large-scale renewable energy integration.Concurrent with thes...Significant advances in battery and fuel cell technologies over the past decade have catalyzed the transition toward electrified transportation systems and large-scale renewable energy integration.Concurrent with these developments,the interdisciplinary role of mechanics has emerged as a critical research frontier.展开更多
Electrocatalysis has been extensively explored for the storage and conversion of renewable electric power.Understanding the physisorption and chemisorption processes at electrified solid–liquid interfaces(ESLIs)is cr...Electrocatalysis has been extensively explored for the storage and conversion of renewable electric power.Understanding the physisorption and chemisorption processes at electrified solid–liquid interfaces(ESLIs)is crucial for revealing the typical surface restructuring and catalyst dissolution during electrocatalysis.Although advanced in situ tools and theoretical models have been proposed[1,2],identifying the nature of the active sites with atomic-scale spatial resolution remains a challenge,especially at ESLIs.In a recent work published in Nature,Zhang et al.[3]reported a groundbreaking atomic-resolution imaging of the structural dynamics of Cu nanowire catalysts in ESLIs for electrochemical CO_(2)reduction(ECR).展开更多
Current works of environmental perception for connected autonomous electrified vehicles(CAEVs)mainly focus on the object detection task in good weather and illumination conditions,they often perform poorly in adverse ...Current works of environmental perception for connected autonomous electrified vehicles(CAEVs)mainly focus on the object detection task in good weather and illumination conditions,they often perform poorly in adverse scenarios and have a vague scene parsing ability.This paper aims to develop an end-to-end sharpening mixture of experts(SMoE)fusion framework to improve the robustness and accuracy of the perception systems for CAEVs in complex illumination and weather conditions.Three original contributions make our work distinctive from the existing relevant literature.The Complex KITTI dataset is introduced which consists of 7481 pairs of modified KITTI RGB images and the generated LiDAR dense depth maps,and this dataset is fine annotated in instance-level with the proposed semi-automatic annotation method.The SMoE fusion approach is devised to adaptively learn the robust kernels from complementary modalities.Comprehensive comparative experiments are implemented,and the results show that the proposed SMoE framework yield significant improvements over the other fusion techniques in adverse environmental conditions.This research proposes a SMoE fusion framework to improve the scene parsing ability of the perception systems for CAEVs in adverse conditions.展开更多
Conventional maintenance mode for the traction power supply system(TPSS)is to perform scheduled regular maintenance activities for power supply equipment,while such maintenance mode may result in undue maintenance tas...Conventional maintenance mode for the traction power supply system(TPSS)is to perform scheduled regular maintenance activities for power supply equipment,while such maintenance mode may result in undue maintenance tasks and low efficiency due to different degradation processes of different sorts of equipment.To address this problem,this paper introduces a preventive opportunistic maintenance(POM)method for TPSS based on equipment reliability.Firstly,a POM model is established by considering the equipment reliability degradation process based on Weibull distribution.Then,by considering the total power outage time in the planned operation cycle of TPSS as the optimization objective,the optimal maintenance scheme of TPSS is formulated by iterative method of maintenance strategies.The proposed method is verified by introducing practical maintenance strategies and fault record data of the traction transformer,circuit breaker and disconnector in an actual TPSS of a railway administration.Results show that the presented method can make full use of the existing fault data to develop a POM scheme for TPSS.It can improve maintenance efficiency and reduce power outage time,providing guidance to formulate scientific maintenance strategies for TPSS.展开更多
The autotransformer(AT)neutral current ratio method is widely used for fault location in the AT traction power network.With the development of high-speed electrified railways,a large number of data show that the relat...The autotransformer(AT)neutral current ratio method is widely used for fault location in the AT traction power network.With the development of high-speed electrified railways,a large number of data show that the relation between the AT neutral current ratio and the distance from the beginning of the fault AT section to the fault point(Q-L relation)is mostly nonlinear.Therefore,the linear Q-L relation in the traditional fault location method always leads to large errors.To solve this problem,a large number of load-related current data that can be used to describe the Q-L relation are obtained through the load test of the electric multiple unit(EMU).Thus,an improved fault location method based on the back propagation(BP)neural network is proposed in this paper.On this basis,a comparison between the improved method and the traditional method shows that the maximum absolute error and the average absolute error of the improved method are 0.651 km and 0.334 km lower than those of the traditional method,respectively,which demonstrates that the improved method can effectively eliminate the influence of nonlinear factors and greatly improve the accuracy of fault location for the AT traction power network.Finally,combined with a shortcircuit test,the accuracy of the improved method is verified.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52107126 and52077179)the Key Regional Innovation and Development Joint Fund Project(No.2023YFB2303901)the funding of Chengdu Guojia Electrical Engineering Co.,Ltd.(No.NEEC-2022-B11).
文摘The regenerative braking energy utilization system(RBEUS)stands as a promising technique for improving the efficiency and power quality of electrified railways.Beyond the vital aspects of energy management and control strategies,ensuring fault protection is paramount for the secure and steady operation of the traction power supply system(TPSS)integrated with RBEUS.This paper introduces an innovative protection scheme tailored to diverse RBEUS application scenarios.Firstly,fault categories are streamlined into three levels:system,equipment,and warning.Subsequently,a novel multi-port active power differential protection method,aligned with RBEUS operational principles,is crafted to serve as a comprehensive and sensitive main protection.Building upon this foundation,a hierarchical protection structure for RBEUS is established,addressing the intricacies and variations in fault types while boosting anti-disturbance capabilities under faulty conditions.Embracing the principle of railway-oriented safety,a collaborative RBEUS-TPSS protection scheme is put forth.Finally,through simulated scenarios encompassing various fault conditions,the proposed scheme’s feasibility and effectiveness are convincingly validated.
基金National Natural Science Foundation of China(52076105)Natural Science Foundation of Jiangsu Province(BK20171301)。
文摘The cone-jet in electrohydrodynamic atomization has been widely applied into numerous industrial fields owing to micro-sized drops with narrow distribution and high charge.The electrified jet emits from a single capillary sheathed with quartz tube is visualized versus operating parameters and physical properties,and breakup instabilities are also discussed.The range of operating parameters for a steady conejet broadens,as well as the minimum flow rate.Taylor cone angle decreases with an increase in flow rate,while increases as electric potential increasing.The jet breakup length decreases with an increase in flow rate and conductivity,while increases as electric potential increasing.The diffusion angle increases as flow rate increasing,while decrease as electric potential and conductivity increasing.Much clearer whipping instabilities are observed with an increase in“electro-Weber”number and conductivity.The completion in disturbance or/and suppression from axial and radial stresses,drag force dominates the variation.Meanwhile,for a large flow rate,the transition from varicose instabilities to whipping instabilities is found.The whipping instabilities are clearly observed for high conductivity due to much more free ions in liquid.For much higher conductivity,an intermittent electrified jet appears and shows an umbrella plume,and breakup length sharply shortens.
基金supported by Climate Change Special Project of China Meteorological Administration(No CCSF2011-14)
文摘Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and CnHm of electrified railways, and analyzed their dynamic characteristics during the period of 1975 2007. The results show that during this period, the annual mean values of energy saving is 1.23×10^6 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 4.267×10^6 t, 20.5×10^3 t, 3.0×10^3 t, 9.6×10^3 t, 67.9×10^3 t, and 6.9×10^3 t per year, respectively. The annual average increasing rates of energy saving is 139×10^3 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 483×10^3 t, 2.3×10^3 t, 0.34×10^3 t, 1.1×10^3 t, 7.7 ×10^3 t and 0.78×10^3 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China＇s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China＇s railway transportation.
文摘In order to improve the Power Quality(PQ)of traction power supply system and reduce the power rating and operation cost of compensator,a Static VAR Compensator(SVC)integrated Railway Power Conditioner(RPC)is presented in this paper.RPC is a widely used device in the AC electrified railway systems to enhance the PQ indices of the main network.The next generation of this equipment is Active Power Quality Compensator(APQC).The major concern of these compensators is their high kVA rating.In this paper,a hybrid technique is proposed to solve aforementioned problems.A combination of SVC as an auxiliary device is employed together with the main compensators,i.e.,RPC and APQC that leads on to the reduction of power rating of the main compensators.The use of proposed scheme will cause to reduce significantly the initial investment cost of compensation system.The main compensators are only utilized to balance active powers of two adjacent feeder sections and suppress harmonic currents.The SVCs are used to compensate reactive power and suppress the third and fifth harmonic currents.In this paper firstly,the PQ compensation procedure in AC electrified railway is analyzed step by step.Then,the control strategies for SVC and the main compensators are presented.Finally,a simulation is fulfilled using Matlab/Simulink software to verify the effectiveness and validity of the proposed scheme and compensation strategy and also demonstrate that this technique could compensate all PQ problems.
文摘Increasing railway traffic and energy utilization issues prompt electrified railway systems to be more economical,efficient and sustainable.As regenerative braking energy in railway systems has huge potential for optimized utilization,a lot of research has been focusing on how to use the energy efficiently and gain sustainable benefits.The energy storage system is an alternative because it not only deals with regenerative braking energy but also smooths drastic fluctuation of load power profile and optimizes energy management.In this work,we propose a co-phase traction power supply system with super capacitor(CSS_SC)for the purpose of realizing the function of energy management and power quality management in electrified railways.Besides,the coordinated control strategy is presented to match four working modes,including traction,regenerative braking,peak shaving and valley filling.A corresponding simulation model is built in MATLAB/Simulink to verify the feasibility of the proposed system under dynamic working conditions.The results demonstrate that CSS_SC is flexible to deal with four different working conditions and can realize energy saving within the allowable voltage unbalance of 0.008%in simulation in contrast to 1.3%of the standard limit.With such a control strategy,the performance of super capacitor is controlled to comply with efficiency and safety constraints.Finally,a case study demonstrates the improvement in power fluctuation with the valley-to-peak ratio reduced by 20.3%and the daily load factor increased by 17.9%.
基金supported in part by the Scientific Foundation for Outstanding Young Scientists of Sichuan under Grant No.2021JDJQ0032in part by the National Natural Science Foundation of China under Grant No.52107128in part by the Natural Science Foundation of Sichuan Province under Grant No.2022NSFSC0436.
文摘Traction power systems(TPSs)play a vital role in the operation of electrified railways.The transformation of conventional railway TPSs to novel structures is not only a trend to promote the development of electrified railways toward high-efficiency and resilience but also an inevitable requirement to achieve carbon neutrality target.On the basis of sorting out the power supply structures of conventional AC and DC modes,this paper first reviews the characteristics of the existing TPSs,such as weak power supply flexibility and low-energy efficiency.Furthermore,the power supply structures of various TPSs for future electrified railways are described in detail,which satisfy longer distance,low-carbon,high-efficiency,high-reliability and high-quality power supply requirements.Meanwhile,the application prospects of different traction modes are discussed from both technical and economic aspects.Eventually,this paper introduces the research progress of mixed-system electrified railways and traction power supply technologies without catenary system,speculates on the future development trends and challenges of TPSs and predicts that TPSs will be based on the continuous power supply mode,employing power electronic equipment and intelligent information technology to construct a railway comprehensive energy system with renewable energy.
基金funded by Youth Science Foundation Fund Project of National Natural Science Foundation of China(51607148)Science and Technology R&D Program of China State Railway Group Co.,Ltd.(SY2020G001)Project of Sichuan Science and Technology Program(2021YJ0028)。
文摘Purpose–The traction cable is paralleled with the existing traction network of electrified railway through transverse connecting line to form the scheme of long distance power supply for the traction network.This paper aims to study the scheme composition and power supply distance(PSD)of the scheme.Design/methodology/approach–Based on the structure of parallel traction network(referred to as“cable traction network(CTN)”),the power supply modes(PSMs)are divided into cableþdirect PSM and cableþautotransformer(AT)PSM(including Japanese mode,French mode and new mode).Taking cableþJapanese AT PSM as an example,the scheme of long distance power supply for CTN under the PSMs of co-phase and out-of-phase power supply are designed.On the basis of establishing the equivalent circuit model and the chain circuit model of CTN,taking the train working voltage as the constraint condition,and based on the power flow calculation of multiple train loads,the calculation formula and process for determining the PSD of CTN are given.The impedance and PSD of CTN under the cableþAT PSM are simulated and analyzed,and a certain line is taken as an example to compare the scheme design.Findings–Results show that the equivalent impedance of CTN under the cableþAT PSM is smaller,and the PSD is about 2.5 times of that under the AT PSM,which can effectively increase the PSD and the flexibility of external power supply location.Originality/value–The research content can effectively improve the PSD of traction power supply system and has important reference value for the engineering application of the scheme.
基金funding from CONAHCYT in the form of a scholarship as a member of the National System of Researchers(CVU:969467)the financial support of the FEMSA foundation.
文摘Centrifugal microfluidic platforms are highly regarded for their potential in multiplexing and automation,as well as their wide range of applications,especially in separating blood plasma and manipulating two-phase flows.However,the need to use stroboscopes or high-speed cameras for monitoring these tasks hinders the extensive use of these platforms in research and commercial settings.In this study,we introduce an innovative and cost-effective strategy for using an array of light-dependent resistors(LDRs)as optical sensors in microfluidic devices,particularly centrifugal platforms.While LDRs are attractive for their potential use as photodetectors,their bulky size frequently restricts their ability to provide high-resolution detection in microfluidic systems.Here,we use specific waveguides to direct light beams from narrow apertures onto the surface of LDRs.We integrated these LDRs into electrified Lab-on-a-Disc(eLOD)devices,with wireless connectivity to smartphones and laptops.This enables many applications,such as droplet/particle counting and velocity measurement,concentration analysis,fluidic interface detection in multiphase flows,real-time monitoring of sample volume on centrifugal platforms,and detection of blood plasma separation as an alternative to costly stroboscope devices,microscopes,and high-speed imaging.We used numerical simulations to evaluate various fluids and scenarios,which include rotation speeds of up to 50 rad/s and a range of droplet sizes.For the testbed,we used the developed eLOD device to analyze red blood cell(RBC)deformability and improve the automated detection of sickle cell anemia by monitoring differences in RBC deformability during centrifugation using the sensors’signals.In addition to sickle cell anemia,this device has the potential to facilitate low-cost automated detection of other medical conditions characterized by altered RBC deformability,such as thalassemia,malaria,and diabetes.
基金This project has been supported in the frame of the BIS-Funded Programme 113167the Royal Society project 1130182 and European Union project H2020-MSCA-RISE 778104.
文摘An overview of current thermal challenges in transport electrification is introduced in order to underpin the research developments and trends of recent thermal management techniques.Currently,explorations of intelligent thermal management and control strategies prevail among car manufacturers in the context of climate change and global warming impacts.Therefore,major cutting-edge systematic approaches in electrified powertrain are summarized in the first place.In particular,the important role of heating,ventilation and air-condition system(HVAC)is emphasised.The trends in developing efficient HVAC system for future electrified powertrain are analysed.Then electric machine efficiency is under spotlight which could be improved by introducing new thermal management techniques and strengthening the efforts of driveline integrations.The demanded integration efforts are expected to provide better value per volume,or more power output/torque per unit with smaller form factor.Driven by demands,major thermal issues of high-power density machines are raised including the comprehensive understanding of thermal path,and multiphysics challenges are addressed whilst embedding power electronic semiconductors,non-isotropic electromagnetic materials and thermal insulation materials.Last but not least,the present review has listed several typical cooling techniques such as liquid cooling jacket,impingement/spray cooling and immersion cooling that could be applied to facilitate the development of integrated electric machine,and a mechanic-electric-thermal holistic approach is suggested at early design phase.Conclusively,a brief summary of the emerging new cooling techniques is presented and the keys to a successful integration are concluded.
文摘Removing high-risk and persistent contaminants from water is challenging,because they typically exist at low concentrations in complex water matrices.Electrified flow-through technologies are viable to overcome the limitations induced by mass transport for efficient contaminant removal.Modifying the local environment of the flow-through electrodes offers opportunities to further improve the reaction kinetics and selectivity for achieving near-complete removal of these contaminants from water.Here,we present state-of-the-art local environment modification approaches that can be incorporated into electrified flow-through technologies to intensify water treatment.We first show methods of nanospace incorporation,local geometry adjustment,and microporous structure optimization that can induce spatial confinement,enhanced local electric field,and microperiodic vortex,respectively,for local environment modification.We then discuss why local environment modification can complement the flow-through electrodes for improving the reaction rate and selectivity.Finally,we outline appropriate scenarios of intensifying electrified flow-through technologies through local environment modification for fit-for-purpose water treatment applications.
基金The authors express their great appreciation for the support of National Natural Science Funds for Distinguished Young Scholar(52125601)Natural Science Foundation of Hubei Province,China(2022CFA031)+1 种基金the Open Fund of State Key Laboratory of New Textile Materials and Advanced Processing Technologies(FZ2022005)the Interdisciplinary Research Program of Huazhong University of Science and Technology(2023JCYJ004).
文摘In response to the current energy and environmental challenges,reducing or replacing reliance on fossil fuels and striving for carbon neutrality seems to be the only viable choice.Recently,a cutting-edge,eco-friendly method of chemical synthesis via transient Joule heating(JH)demonstrated significant promise across various domains,including methane reforming,ammonia synthesis,volatile organic compounds removal,plastic recycling,the synthesis of functional carbon materials from repurposed solid waste,etc.In this review,the advantages,and latest developments in thermochemical synthesis by flash and transient JH are comprehensively outlined.Unlike the ongoing heating process of conventional furnaces that consume fossil fuels,dynamic and transient JH can get significantly higher reaction rates,energy efficiency,flexibility,and versatility.Subsequently,the transient reaction mechanism,data science optimization,and scale-up production models are discussed,and prospects for the integration of the electrified chemical industry with renewable energy for carbon neutrality and long-term energy storage are also envisioned.
基金This work was partially supported by the National Natural Science Foundation of China(No.62271023)the Beijing Natural Science Foundation(No.7202102)the Fundamental Research Funds for Central Universities.
文摘The resting potential is the potential difference that exists between the inner and outer sides of the cell membrane when the cell is not stimulated.The resting membrane potential is a key regulator of phenomena such as cell proliferation,morphogenesis,migration and differentiation.In this paper,we proposed a model of electrified cell clusters that considers the resting potential of cell clusters in the resting state.By measuring the potential difference between the inner and outer sides of biological tissues,it is verified that the cell cluster has a negative potential difference when taking the outer potential as the reference.In the absence of external conductors,the tissue is electrically neutral;while in the presence of external conductors,the positive net charges escape freely under repulsive forces and the biological tissues form a negative electrical equilibrium system.The model proposed in this study explored the potential situation above the cellular level in the resting state,providing a new perspective for the research on resting potential.
基金funded by the National Natural Science Foundation of China(52167013)the Key Program of Natural Science Foundation of Gansu Province(24JRRA225)Natural Science Foundation of Gansu Province(23JRRA891).
文摘In the context of the“dual carbon”goals,to address issues such as high energy consumption,high costs,and low power quality in the rapid development of electrified railways,this study focused on the China Railways High-Speed 5 Electric Multiple Unit and proposed a mathematical model and capacity optimization method for an onboard energy storage system using lithium batteries and supercapacitors as storage media.Firstly,considering the electrical characteristics,weight,and volume of the storage media,a mathematical model of the energy storage system was established.Secondly,to tackle problems related to energy consumption and power quality,an energy management strategy was proposed that comprehensively considers peak shaving and valley filling and power quality by controlling the charge/discharge thresholds of the storage system.Thecapacity optimization adopted a bilevel programming model,with the series/parallel number of storage modules as variables,considering constraints imposed by the Direct Current to Direct Current converter,train load,and space.An improved Particle Swarm Optimization algorithm and linear programming solver were used to solve specific cases.The results show that the proposed onboard energy storage system can effectively achieve energy savings,reduce consumption,and improve power qualitywhile meeting the load and space limitations of the train.
文摘The 2025 Shanghai Auto Show reaffirmed its role as one of the world’s most influential automotive industry events,offering a panoramic view of the future shaped by intelligent and electrified vehicles.With over 200 new models on display-85 percent of them new energy vehicles-this year’s show spotlighted how the global auto industry is pivoting rapidly towards an era of software-defined and AI-powered mobility.
文摘Significant advances in battery and fuel cell technologies over the past decade have catalyzed the transition toward electrified transportation systems and large-scale renewable energy integration.Concurrent with these developments,the interdisciplinary role of mechanics has emerged as a critical research frontier.
基金financially supported by the Natural Science Foundation of Shandong(ZR2023ME014)。
文摘Electrocatalysis has been extensively explored for the storage and conversion of renewable electric power.Understanding the physisorption and chemisorption processes at electrified solid–liquid interfaces(ESLIs)is crucial for revealing the typical surface restructuring and catalyst dissolution during electrocatalysis.Although advanced in situ tools and theoretical models have been proposed[1,2],identifying the nature of the active sites with atomic-scale spatial resolution remains a challenge,especially at ESLIs.In a recent work published in Nature,Zhang et al.[3]reported a groundbreaking atomic-resolution imaging of the structural dynamics of Cu nanowire catalysts in ESLIs for electrochemical CO_(2)reduction(ECR).
基金Supported by National Natural Science Foundation of China(Grant Nos.51975118,52025121,51975103,51905095)National Natural Science Foundation of Jiangsu Province(Grant No.BK20180401).
文摘Current works of environmental perception for connected autonomous electrified vehicles(CAEVs)mainly focus on the object detection task in good weather and illumination conditions,they often perform poorly in adverse scenarios and have a vague scene parsing ability.This paper aims to develop an end-to-end sharpening mixture of experts(SMoE)fusion framework to improve the robustness and accuracy of the perception systems for CAEVs in complex illumination and weather conditions.Three original contributions make our work distinctive from the existing relevant literature.The Complex KITTI dataset is introduced which consists of 7481 pairs of modified KITTI RGB images and the generated LiDAR dense depth maps,and this dataset is fine annotated in instance-level with the proposed semi-automatic annotation method.The SMoE fusion approach is devised to adaptively learn the robust kernels from complementary modalities.Comprehensive comparative experiments are implemented,and the results show that the proposed SMoE framework yield significant improvements over the other fusion techniques in adverse environmental conditions.This research proposes a SMoE fusion framework to improve the scene parsing ability of the perception systems for CAEVs in adverse conditions.
基金the National Natural Science Foundation of China under Grant(51907166)the Science and Technology Project of CHINA RAILWAY under Grant(2017J001-F&N2018G023)the Sichuan Science and Technology Program under Grant(2018GZ0020).
文摘Conventional maintenance mode for the traction power supply system(TPSS)is to perform scheduled regular maintenance activities for power supply equipment,while such maintenance mode may result in undue maintenance tasks and low efficiency due to different degradation processes of different sorts of equipment.To address this problem,this paper introduces a preventive opportunistic maintenance(POM)method for TPSS based on equipment reliability.Firstly,a POM model is established by considering the equipment reliability degradation process based on Weibull distribution.Then,by considering the total power outage time in the planned operation cycle of TPSS as the optimization objective,the optimal maintenance scheme of TPSS is formulated by iterative method of maintenance strategies.The proposed method is verified by introducing practical maintenance strategies and fault record data of the traction transformer,circuit breaker and disconnector in an actual TPSS of a railway administration.Results show that the presented method can make full use of the existing fault data to develop a POM scheme for TPSS.It can improve maintenance efficiency and reduce power outage time,providing guidance to formulate scientific maintenance strategies for TPSS.
基金supported by the National Key Research and Development Program of China(No.2021YFB2601500)the Natural Science Foundation of Sichuan Province(No.2022NSFSC0405)。
文摘The autotransformer(AT)neutral current ratio method is widely used for fault location in the AT traction power network.With the development of high-speed electrified railways,a large number of data show that the relation between the AT neutral current ratio and the distance from the beginning of the fault AT section to the fault point(Q-L relation)is mostly nonlinear.Therefore,the linear Q-L relation in the traditional fault location method always leads to large errors.To solve this problem,a large number of load-related current data that can be used to describe the Q-L relation are obtained through the load test of the electric multiple unit(EMU).Thus,an improved fault location method based on the back propagation(BP)neural network is proposed in this paper.On this basis,a comparison between the improved method and the traditional method shows that the maximum absolute error and the average absolute error of the improved method are 0.651 km and 0.334 km lower than those of the traditional method,respectively,which demonstrates that the improved method can effectively eliminate the influence of nonlinear factors and greatly improve the accuracy of fault location for the AT traction power network.Finally,combined with a shortcircuit test,the accuracy of the improved method is verified.
