Calculation of Electromagnetic Forces for EDS Type Maglev Using 3-D Finite Element Model

2021 ◽  
Author(s):  
Seonbin Lim ◽  
Junsun Yoo ◽  
No-Cheol Park
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Vertical Direction ◽  
Lateral Vibration ◽  
Maglev Train ◽  
Maglev Vehicle ◽  
Study Results ◽  
Propulsion Force ◽  
Simulation Results ◽  
Excitation Force

Abstract Electrodynamic (EDS) type suspension is appropriate for a high-speed maglev train as control is not essential to levitate a train. However, the trains might oscillate large in the vertical direction since there is no control for the EDS type maglev train. Linear Synchronous Motor (LSM) is used to propel trains as it can generate large propulsion force with high efficiency. LSM generate periodic, not uniform, Electromagnetic (EM) force and it cause vertical and lateral vibration. Therefore, EM forces acting on a maglev vehicle should be investigated to determine the vibration characteristics of a high-speed maglev train. An excitation force on bogies is nonlinearly changed by air gap between ground coils and magnets on bogies. Therefore, relative position of guide and a bogie could be defined to contracting time variant excitation force. The study focuses on verifying vertical and lateral vibration due to LSM that makes repeating propulsion force to a maglev vehicle. We made a transient 3-D EM analysis model that could simulate levitation and guidance force of a maglev vehicle. The model was constructed based on straight rail of the conventional maglev system, L0 series in Japan. We compared the simulation results, levitation, and guidance forces on single ground coil, with another study results. Also, total EM forces on a bogie in simulation results was compared with real track experimental results of another study. We could evaluate ride comport and running stability using our transient EM force by coupling with rigid body simulation.

scholarly journals Aerodynamic Analysis of Pressure Wave of High-Speed Maglev Vehicle Crossing: Modeling and Calculation

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3770
Author(s):  
Gao ◽  
Ni ◽  
Lin ◽  
Luo ◽  
Ji
Keyword(s):  
Pressure Wave ◽  
High Speed ◽  
Calculation Model ◽  
The Body ◽  
Aerodynamic Load ◽  
Maglev Train ◽  
Aerodynamic Analysis ◽  
Simulation Techniques ◽  
Maglev Vehicle ◽  
Full Speed

When two maglev trains travel in opposite directions on two adjacent tracks, train crossingis inevitable. Especially when both trains run at full speed, the pressure wave formed by each otherwill have a significant impact on the structure of the vehicle. Therefore, it is important to understandthe pressure distribution on the body surface during the crossing to mitigate impact of the pressurewave. In this work, numerical simulation techniques are employed to reveal the nature of pressurewave during train crossing. Firstly, the aerodynamic load calculation model and the pressure wavecalculation model are established, based on the turbulence model and flow field control equation.Secondly, the governing equations are discretized together with determined correspondingboundary conditions, which leads to an effective numerical analysis method. Finally, thecorresponding aerodynamic analysis is carried out for the high-speed maglev test vehicle runningat speed 500 km/h on the open-air line. The simulation results reveal that the spot which sustainsthe most pressure fluctuation is at the widest part of the vehicle during the train crossing. This formsvaluable insights on the aerodynamic nature of high-speed maglev train and provides necessaryinputs to the structural design of the vehicle.

A Study on the Aerodynamic Safety of Skirt Board Structure on Maglev Train

2011 ◽  
Vol 138-139 ◽  
pp. 836-841
Author(s):  
Zhi Qiang Liu ◽  
Wei Hua Ma ◽  
Shi Hui Luo
Keyword(s):  
High Speed ◽  
Aerodynamic Resistance ◽  
Board Structure ◽  
Maglev Train ◽  
Study Results ◽  
The Stability ◽  
Safety Limit

Utilizing CFD, the influences of skirt board structure on high speed maglev train's aerodynamic resistance and the stability under crosswind are studied. Studies have been conducted on the aerodynamic of skirt boards which located on different positions. Simulation analyses are finished with maglev train running at speed of 350km/h for both with and without crosswind. Study results show that, some skirt boards are likely to be pulled apart, further, lower the safety limit speed.

Research on Modeling and Simulation of Power Electronic Circuits Based on MATLAB

2014 ◽  
Vol 687-691 ◽  
pp. 3106-3109 ◽  
Author(s):  
Quan Guo ◽  
Kun Xu ◽  
Fang Yi Sun ◽  
Xue Qian Li
Keyword(s):  
Modeling And Simulation ◽  
Design Process ◽  
High Speed ◽  
High Efficiency ◽  
System Structure ◽  
Power Electronic ◽  
Electronic Circuits ◽  
Actual System ◽  
Power Electronic Circuits ◽  
Simulation Results

the example of three-phase bridge controlled rectifying circuit discussed the method of the utilization of MATLAB SIMULINK on the modeling and simulation of power electronic circuits, and gave the simulation result waveform, verifying the convenience, intuition, high-efficiency, high speed, genuineness and accuracy of this method. This method can also make modeling and simulation on quite complex circuits, power electronic conversion system, and electric drive automatic control system. The systematic modeling is very similar to the design process of the actual system. Users can get the simulation results of the system quickly without programming and the deduction of mathematical models of circuits and systems. The analysis on the simulation results can transform the system structure or modify relevant parameters in order to make the system get the required results and performance, which can greatly accelerate the analysis or design process of the system.

Dynamic Analysis of a Coupled System of High-Speed Maglev Train and Curved Viaduct

2018 ◽  
Vol 18 (11) ◽  
pp. 1850143 ◽  
Author(s):  
Z. L. Wang ◽  
Y. L. Xu ◽  
G. Q. Li ◽  
S. W. Chen ◽  
X. L. Zhang
Keyword(s):  
Dynamic Analysis ◽  
High Speed ◽  
Coupled System ◽  
Dynamic Responses ◽  
Global Coordinate System ◽  
Maglev Train ◽  
Horizontally Curved ◽  
Maglev Vehicle ◽  
Initial Equilibrium State ◽  
Stiffness And Damping

This study presents a framework for dynamic analysis of a coupled system of high-speed maglev train and curved viaduct. A series of trajectory coordinates are used to define the motion of maglev vehicles moving over a horizontally curved track, the stiffness and damping matrices of the equations can be thus reduced into those of the straight track. The curved viaduct system is modeled in the global coordinate system using the finite element method, in which the inner and outer rails in the different horizontal planes are duly included. The electromagnet force-air gap model is adopted for the maglev vehicle via its electromagnets and rails on the viaduct, by appropriate transformation of coordinates. By applying the proposed framework to the Shanghai maglev line, curved path-induced dynamic responses and characteristics of the vehicle are explored, which agree well with the measurement ones. The dynamic responses of the curved viaduct are also examined in the vertical, lateral and rotational directions by comparison with the straight viaduct. Moreover, the effect of various curve radii and cant deficiencies on the coupled system are investigated. The results show that for a maglev vehicle moving with an initial equilibrium state, its lateral and rotational response are mainly excited by track roughness. In addition to the track radius, cant deficiencies significantly affect the operational safety of the viaduct.

scholarly journals Development of Propulsion Inverter Control System for High-Speed Maglev Based on LS-LSM

2017 ◽  
Author(s):  
Jeong-Min Jo ◽  
Jin-Ho Lee ◽  
Young-Jae Han ◽  
Chang-Young Lee ◽  
Kwan-Sub Lee
Keyword(s):  
Control System ◽  
Real Time ◽  
Dynamic Property ◽  
Single Unit ◽  
High Speed ◽  
Maglev Train ◽  
Synchronous Motors ◽  
Maglev Vehicle ◽  
Propulsion Control ◽  
Linear Synchronous Motors

In the case of long-stator linear drive, unlike rotative drives for which speed or position sensors are a single unit attached to the shaft, these sensors extend along the guideway. The position signals transmitted from maglev vehicle can’t meet the need of the real-time propulsion control in the on-ground inverter power substations. In this paper the design of the propulsion inverter control system with a position estimator for driving long-stator synchronous motor in high speed maglev train is proposed. The experiments have been carried out at the 150m long guideway in O-song test track. To investigate the performance of the position estimator, the propulsion control system with and without the position estimator are compared. The result confirms that the proposed strategy can meet the dynamic property need of propulsion inverter control system for driving long-stator linear synchronous motors

scholarly journals A method of thrust ripple suppression for long stator linear synchronous motor

2018 ◽  
Vol 4 (2) ◽  
pp. 30-44
Author(s):  
Siyuan Mu ◽  
Jinsong Kang ◽  
Shuo Wang ◽  
Yusong Liu ◽  
Cuiwei He
Keyword(s):  
High Speed ◽  
Reference Frames ◽  
High Efficiency ◽  
Synchronous Motor ◽  
Low Noise ◽  
Good Prospect ◽  
Maglev Train ◽  
Harmonic Current ◽  
Current Harmonics ◽  
Linear Synchronous Motor

With the advantages of high speed, low noise and high efficiency, the electromagnetic suspension (EMS) type maglev train has a good prospect in railway transportation. It is based on the long stator linear synchronous motor (LSLSM). However, due to cogging effect, end effect and the harmonics in the stator current and flux density distribution around the air-gap, the thrust generated by the LSLSM fluctuates. The thrust ripple brings noise, drop of control accuracy, even causes the resonance of train. In this paper, the thrust ripple produced by the cogging effect and flux linkage harmonics is analyzed. Then a method of harmonic current injection is proposed to compensate cogging force and reduce the thrust ripple, without influence the decoupling control of traction and suspension system. The injected current harmonics are controlled under multiple rotating reference frames independently. Finally, based on voltage equations of harmonics, the decoupled harmonic current controllers with harmonic voltage feedforward are designed, which improve the performance of current harmonics response and thrust ripple suppression. Simulation results on Simulink verify the effectiveness of proposed thrust ripple suppression method for LSLSM.

One-step Separation and Purification of Four Phenolic Acids from Stenoloma chusanum (L.) Ching by Medium-pressure Liquid Chromatography and High-speed Counter-current Chromatography

2019 ◽  
Vol 9 (2) ◽  
pp. 138-143
Author(s):  
Tianyun Li ◽  
Xiling Dai ◽  
Yichen Li ◽  
Guozheng Huang ◽  
Jianguo Cao
Keyword(s):  
Natural Products ◽  
Liquid Chromatography ◽  
Phenolic Acids ◽  
High Speed ◽  
High Efficiency ◽  
Total Phenolic ◽  
Medium Pressure ◽  
Medium Pressure Liquid Chromatography ◽  
One Step ◽  
Counter Current

Background:Stenoloma chusanum (L.) Ching is a Chinese traditional medicinal fern with high total flavonoid and total phenolic content. Traditionally, phenolic compounds were separated by using column chromatography, which is relatively inefficient. </P><P> Objective: This study aims to use an efficient method to separate natural products from S. chusanum by Medium-Pressure Liquid Chromatography (MPLC) and High-Speed Counter-Current Chromatography (HSCCC).Methods:In the present research, firstly, a sample (2.5 g) from the dichloromethane extract of S. chusanum was separated by MPLC. Next, fraction P5 was purified by HSCCC with a two-phase solvent system composed of hexane-ethyl acetate-methanol-water (HEMWat) at a volume ratio of 2:4:1:4 (v/v/v/v). </P><P> Result: Four phenolic acids were obtained and their structures were identified by means of NMR and ESI-mass analysis. They were identified as: 1) protocatechuic acid (34 mg, purity 90.1%), 2) syringic acid (66 mg, purity 99.0%), 3) p-hydroxybenzoic acid (5 mg, purity 91.2%) and 4) vanillic acid (6 mg, purity 99.3%).Conclusion:The combination of MPLC and HSCCC is a high-efficiency separation method for natural products. This is the first report with regard to the separation of four phenolic acids in one step by MPLC and HSCCC from S. chusanum (L.) Ching.

Tail shapes lead to different propulsive mechanisms in the body/caudal fin undulation of fish

2020 ◽  
pp. 095440622096768
Author(s):  
Jialei Song ◽  
Yong Zhong ◽  
Ruxu Du ◽  
Ling Yin ◽  
Yang Ding
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Efficiency ◽  
The Body ◽  
Caudal Fin ◽  
Fish Model ◽  
Swimming Efficiency ◽  
Simulation Results ◽  
Propulsive Mechanism ◽  
High Depth

In this paper, we investigate the hydrodynamics of swimmers with three caudal fins: a round one corresponding to snakehead fish ( Channidae), an indented one corresponding to saithe ( Pollachius virens), and a lunate one corresponding to tuna ( Thunnus thynnus). A direct numerical simulation (DNS) approach with a self-propelled fish model was adopted. The simulation results show that the caudal fin transitions from a pushing/suction combined propulsive mechanism to a suction-dominated propulsive mechanism with increasing aspect ratio ( AR). Interestingly, different from a previous finding that suction-based propulsion leads to high efficiency in animal swimming, this study shows that the utilization of suction-based propulsion by a high- AR caudal fin reduces swimming efficiency. Therefore, the suction-based propulsive mechanism does not necessarily lead to high efficiency, while other factors might play a role. Further analysis shows that the large lateral momentum transferred to the flow due to the high depth of the high- AR caudal fin leads to the lowest efficiency despite the most significant suction.

Research on springback characteristic in flexible multi-points 3D stretch-bending process

2021 ◽  
pp. 095440542110284
Author(s):  
Song Gao ◽  
Tonggui He ◽  
Qihan Li ◽  
Yingli Sun ◽  
Jicai Liang
Keyword(s):  
Simulation Model ◽  
High Efficiency ◽  
Vertical Direction ◽  
Factors Affecting ◽  
Stretch Bending ◽  
Element Simulation ◽  
Bending Process ◽  
Bending Radius ◽  
Aluminum Profiles ◽  
Bending Sequence

The problem of springback is one of the most significant factors affecting the forming accuracy for aluminum 3D stretch-bending parts. In order to achieve high-efficiency and high-quality forming of such kind of structural components, the springback behaviors of the AA6082 aluminum profiles are investigated based on the flexible multi-points 3D stretch-bending process (3D FSB). Firstly, a finite element simulation model for the 3D FSB process was developed to analyze the forming procedure and the springback procedure. The forming experiments were carried out for the rectangle-section profile to verify the effectiveness of the simulation model. Secondly, the influence of tension on springback was studied, which include the pre-stretching and the post-stretching. Furthermore, the influences of the bending radius and bending sequence are revealed. The results show that: (1) The numerical model can be used to evaluate the effects of bending radius and process parameters on springback in the 3D FSB process effectively. (2) The pre-stretching has little effect on the horizontal springback reduction, but it plays a prominent role in reducing the springback in the vertical direction. (3) The increase of bending deformation in any direction will lead to an increase of springback in its direction and reduce the springback in the other direction. Besides, it reduces the relative error in both directions simultaneously. This research established a foundation to achieve the precise forming of the 3D stretch-bending parts with closed symmetrical cross-section.

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