High-speed Maglev Research Articles

Practical investigation of future perspectives and limitations of maglev technologies

Results of an International Survey among Transport Experts and Specialists Maglev.
 With the aim of tracking current trends in the market perspectives of magnetic levitation, or maglev technologies, the non-profit International Maglev Board conducted a primary study in the spring of 2018 among maglev specialists and transportation professionals. More than 1 000 professionals took part in the survey. Main topics of the study are questions comparing the suitability of conventional wheel-on-rail and maglev technologies according to application areas. Predicted opportunities and developments in maglev technology, acceptance issues and research needs are analyzed. The results are broken down by expertise and nationality of the participants. This short version presents selected findings of the survey in compressed form.
 Background: There is an obvious need for information on international trends in the application of Maglev transport technologies. The study attempts to grasp the global dimension of magnetic levitation developments in a structured way.
 Aim: To track current trends in magnetic levitation transport system innovation. Identify perspectives, research tasks and implementation barriers. Comparison of magnetic levitation systems with steel wheel systems. Analysis of the key topics of the debate.
 Methods: Primary study in spring 2018 among 1 058 maglev specialists and transport experts. Internet-based online survey.
 Results: The ratings vary greatly according to the expertise and origin of the respondents. In certain fields of application, wheel-rail systems remain the preferred transport technology. But in certain other fields of application, maglev technologies have become preferred over conventional steel-wheel-rail by a majority of transport professionals. This is particularly the case for high-speed maglev transport and for the new application of maglev elevators in buildings. At the same time, many respondents see a continuing need for research.
 Conclusion: Overall, there is a differentiated picture. Respondents from North and South America, Russia and Asia are on average particularly open to an implementation of certain maglev technologies.

Energy consumption of track-based high-speed trains: maglev systems in comparison with wheel-rail systems

Background: The energy consumption of a high-speed system is an important part of its total operational costs. This paper compares the secondary energy demand of different wheel-rail systems, such as ICE, TGV and Shinkansen, and maglev systems, such as Transrapid and Chuo Shinkansen.
 In the past, energy values of systems with different conditions (train configuration, dimension, capacity, maximum speed) were frequently compared. The comparative values were often represented by the specific energy consumption based on passenger capacity and line-kilometer values.
 Aim: The goal is to find a way to compare the specific energy consumption of different high-speed systems without any distortion of results.
 Methods: A comparison of energy values based on normative usable areas inside the high-speed systems will be described and evaluated in this paper, transforming the results to a more distortion-free comparison of energy consumption of different systems.
 Results: The results show the energy consumption as an important characteristic parameter of high-speed transportation systems based on an objective comparison and give ranges of expected energy demand of different systems dependent on maximum speed level.
 Conclusion: Up to the design speed of wheel-rail systems there are slight advantages in terms of energy consumption for the Transrapid maglev. From the perspective of energy consumption under consideration to reduce travel time, high-speed maglev systems represent a promising option for new railway projects. However, a project-specific system decision must be based on a complete life-cycle cost analysis, including investment cost

Dynamic interaction analysis of the high-speed maglev vehicle/guideway system based on a field measurement and model updating method

Practical simulation technology is of great importance in the design and research of the maglev system. This paper presents a practical vehicle/guideway model based on an in situ vibration test and model updating method. In this model, the guideway is established by the Finite Element method and then updated by the measurement, and the vehicle is simulated as a 10-degree-of-freedom model, which consists of a car-body and eight magnets. The vehicle interacts with the guideway by the magnetic interactive forces, which are tuned by the current feedback controller. The vehicle/guideway interaction problem is solved by the proposed incremental iteration procedure. Two case studies including the Shanghai High-speed Maglev Commercial Operational Line and the High-speed Maglev Test Line at Tongji University were presented for the validation of the proposed model. Finally, the effects of random surface irregularity and distributed magnetic forces were investigated here, and the frequency response of the guideway was analyzed in detail. The results indicate that the proposed model can provide a practical response prediction and analysis because the dynamic characteristics of the guideway and the excitation frequency of the maglev train are reasonably considered in this model.

THE FAULT LOCATING SYSTEM OF THE HIGH-SPEED MAGLEV TRAIN

Analyzing and researching the levitation and guidance sensor fault location system of high-speed maglev train, we developed an offline testing method of sensor fault location system, which can carry on the fast positioning of sensor boards, and greatly improve the efficiency of maintenance. The research results have certain reference value for maintenance work of Shanghai maglev engineering demonstration line.

Application and further development of Maglev transportation in China

Since the high-speed maglev line in Shanghai was put into operation in 2003, it has been running safely for 15 years, maintaining the highest speed of public ground traffic 430 km/h and 99.8~99.9% punctuality. Since 2001, China ministry of science and technology (MOST) has been supporting the research and development of high speed maglev transportation technology. In 2016, under the support of the MOST, China Railway Rolling stock Corporation (CRRC) started to lead the program of engineering research of Maglev. The aim of the program is to develop 600 km/h high speed Maglev system and 200 km/h medium speed maglev system. The newly developed high speed Maglev system could be tested, verified and applied on the planned Shanghai - Hangzhou high speed Maglev line. 
 Since the operation opening of Changsha Maglev Airport Express Line in May 2016, Hunan province has planned to build more maglev line with top speed 100–160 km/h. Following the operation of urban maglev in Changsha and Beijing, the Qingyuan Maglev line in Guangdong province began to build at the end of 2017. The new maglev line will connect hot spring tourist attractions and Changlong theme park (animal park) in 2019. 
 This paper introduces the application and construction of maglev transportation in China, recent R&D status, further plans and trend of development.

Service experiences Maglev vehicles Shanghai

In the late 1990s thyssenkrupp Transrapid GmbH successfully qualified the Maglev Vehicle TR08 and obtained the type approval certificate. Based on that design, in 2001-2003 three five-car vehicles for the first commercial high speed Maglev Line in Shanghai have been manufactured and set into operation. The VIP-Run took place over 15 years ago and the commercial operation has been running for almost 15 years at great availability.
 The Transrapid system concept of small autonomous redundant electronics based modules facilitates significantly smooth maintenance - diagnosis, testing and system inspection.
 Thanks to intelligent diagnostics, the use of easily interchangeable plug-in units, the dimensioning of the spare parts inventory according to the expected failure rates and the replenishment lead time, the maintenance efforts are still within the forecast range at the beginning of the project. Furthermore, the maintenance concept is essentially unchanged since the beginning.
 There are no special materials that are subject to a potential shortage or price leap, but all according to normal industrial base.
 Thanks to the low level of stress to components on board, most electrical and electronic units are still on-board as original equipment, which are 15 years old and at no end of life is visible.
 But in case of repair or replacement, the challenge is the adaptation to the volatile market of electronic components. This includes the necessary lead-time for adaptive development and qualification, which has to be considered.
 On the side of the vehicle supplier, a small smart team of electronics experts is managing obsolescence and compensates discontinuation.
 The paper tells how it works and appreciates trustful cooperation of the supplier in Europe with the operator in China.

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

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.

A special excitation system for analysis of coupling characteristics of thrust and levitation force of maglev train

Background: In the maglev train propelled by long stator linear synchronous motor (LSLSM), the thrust characteristics are one of important points to evaluate the performance of the system. However, coupling effect exists between the propulsion and levitation system. Therefore, the interference from the levitation system must be considered when the propulsion system is designed.
 Aim: The article focus on the analysis of coupling characteristics of thrust and levitation force of maglev train, and a special excitation system is designed for the study.
 Methods: In order to study the thrust performance under the fluctuating air gap field under laboratory conditions, a rotating synchronous motor has been designed to imitate the long stator linear synchronous motor applied in high speed maglev train. And a special excitation system is designed for the rotating synchronous motor, which can simulate the fluctuation of the exciting current during the actual operation of maglev train. The air gap of the rotating synchronous motor is kept as constant, and the fluctuating excitation current is added to the excitation winding of the rotating synchronous motor, thus the simulation of air gap magnetic field variation is achieved.
 Results: The special excitation system of the experimental motor is introduced in detail.
 Conclusion: The relationship between thrust and levitation force of long stator linear synchronous motor (LSLSM) in maglev train is strong coupling, non-linear, and dynamic. Complete decoupling of thrust and levitation force is not easy to be achieved. The experimental platform has been built to study the coupling characteristics of thrust and levitation force of maglev train.

Hardware-in-the-loop simulation of high-speed maglev transportation five-segment propulsion system based on dSPACE

Aim: For exploring and testing the key technology of high-speed maglev transportation propulsion control system, this paper designs and establishes a hardware-in-the-loop (HIL) real-time simulation system of the high-speed maglev transportation five-segment propulsion system.
 Materials and methods of the studies: According to the route conditions and propulsion segment division of Shanghai maglev demonstration and operation line, the real-time simulation platform based on dSPACE multiprocessor systems is implemented. The simulation system can achieve the functional simulation of all the high-power related equipment in the 5-segment area, including 8 sets of high-power converter units, 2 sets of medium-power converter units, 2 sets of low-power converter units, five-segment trackside switch stations and long-stator linear synchronous motors. The mathematical models of linear motors and converters are built in MATLAB/Simulink and System Generator, after compiling, they can be downloaded and executed in Field Programmable Logic Array (FPGA). All the interfaces connecting the simulation system to the propulsion control system physical equipment use real physical components as in the field, such as analog I/O, digital I/O, optical signals and Profibus.
 Results: By using CPU+FPGA hardware configuration, the simulation steps are greatly shortened and the response speed and accuracy of real-time simulation system are improved. The simulation system can simulate multiple operating modes such as multi-segment, multi-vehicle, double-track, double-feeding, step-by-step stator section changeover, and so on. The simulation results show that the maximum speed of the simulation system can reach 500 km/h.
 Conclusion: This HIL system can provide detailed real-time on-line test and verification of high speed maglev propulsion control system.

Multifunctional linear induction motor with longitudinal-transverce magnetic flux for magnetic-levitational transport

Background: Traction linear induction motors (LIM) at the current stage of human society development are the most promising for high-speed magnetic-levitation transport (MLT) and are already used in a number of commercial projects. Linear induction motors can be executed with longitudinal, transverse and longitudinal-transverse magnetic flux and have a large number of design options.
 Aim: In addition to traction efforts, LIM develops the forces of magnetic-levitation and lateral stabilization (self-stabilization). The efforts of magnetic-levitation of linear induction motors with longitudinal and transverse magnetic flux are very significant in the zone of large slides (at low speeds) and decrease with increasing speed of the magnetic-levitation transport. To a lesser extent, the decrease in slip (at high speeds) affects the magnetic-levitation forces developed by a number of design variants of linear induction motors with a longitudinal-transverse magnetic flux, in which magnetic fields traveling in a transverse direction towards each other are additionally used. This is explained by the fact that at high and low velocities MLT, the LIM slip will be equal to unity relatively oppositely running in the transverse direction of the magnetic fields and the magnetic suspension forces will be maximum.
 Materials and Methods: Running towards each other in the transverse direction of the MLT movement, magnetic fields cross the electrically conductive secondary element (playing the role of the track structure of the high-speed transport system) and induce electromotive forces in it, under the influence of which currents will flow.
 Results: As a result, cross counter-directional mechanical forces are created which, in the symmetrical arrangement of the MLT crew relative to the track structure, are mutually balanced and do not have any effect on the motion of the magnetic-levitation transport. At lateral (transverse) displacement of the high-speed transport on the magnetic suspension relative to the track structure, the equilibrium of the transverse mechanical forces is disrupted and, under the effect of the effort difference, the MLT crew will be automatically returned to the original symmetrical position.
 Conclusion: The distribution of magnetomotive forces (MMF) of a linear induction motor with a longitudinal-transverse magnetic flux, whose magnetic system is formed by the combination of longitudinally and transverse laminated cores, on the teeth of which the coils of a concentrated three-phase winding are located, is considered. The relations are represented in the form of a double Fourier series for calculating the resultant MMF value in the air gap of a linear induction motor with a longitudinal-transverse magnetic flux.

Stiffness of Coupling Connection and Bearing Support for High-Speed Maglev Guideways

Stiffness of Coupling Connection and Bearing Support for High-Speed Maglev Guideways

Analysis on Dynamics Characteristics of Maglev with Loop Type Linear Synchronous Motor Section Change Algorithm using Electro-Mechanical Co-Simulation

A linear synchronous motor (LSM) is generally used for high-speed maglev train propulsion. For the LSM, the permanent magnet is installed on the train and the stator on the railway. But The stator winding is not practical to install the LSM as the same length as the train travel distance because the electric power is supplied to the entire railway at once, power loss will be significant. Therefore, several stators are separated from each other by section and the power is supplied to each section when maglev is on the section. For this purpose, it is necessary to develop an accurate control system to control each section and synchronize adjacent sections during a section change. In this paper we developed a control system for the section change, which is essential for the operation of the Maglev train using the LSM as its propulsion system, and this control system was combined with the multibody dynamics analysis of the Maglev to develop a state-of-the-art control algorithm; the performance of this control algorithm was proven to be excellent. Furthermore, we applied the analysis technique of electro-mechanical coupling system, which can analyze both the control algorithm of the section change and the multibody dynamics analysis of the Maglev at the same time, to examine the running performance of the Maglev train with different design variables in different running conditions.

Numerical simulation of pressure waves induced by high-speed maglev trains passing through tunnels

Numerical simulation of pressure waves induced by high-speed maglev trains passing through tunnels

Influence of track irregularities in high-speed Maglev transportation systems

Track irregularities of high-speed Maglev lines have significant influence on ride comfort. Their adjustment is of key importance in the daily maintenance of these lines. In this study, an adjustment method is proposed and track irregularities analysis is performed. This study considers two modules: an inspection module and a vehicle-guideway coupling vibration analysis module. In the inspection module, an inertial reference method is employed for field-measurements of the Shanghai high-speed Maglev demonstration line. Then, a partial filtering, integration method, resampling method, and designed elliptic filter are employed to analyze the detection data, which reveals the required track irregularities. In the analysis module, a vehicle-guideway interaction model and an electromagnetic interaction model were developed. The influence of the measured line irregularities is considered for the calculations of the electromagnetic force. Numerical integration method was employed for the calculations. Based on the actual field detection results and analysis using the numerical model, a threshold analysis method is developed. Several irregularities modalities with different girder end\'s deviations were considered in the simulations. The inspection results indicated that long-wavelength irregularities with larger girder end\'s deviations were the dominant irregularities. In addition, the threshold analysis of the girder end\' s deviations were considered in the simulations. The inspection results indicated that long-wavelength irregularities with larger girder end\'s deviation shows that irregularities that have a deviation amplitude larger than 6 mm and certain modalities (e.g., M- and N-shape) are unfavorable. These types of irregularities should be adjusted during the daily maintenance.

Modelling and validation of coupled high-speed maglev train-and-viaduct systems considering support flexibility

ABSTRACTThis study presents a more realistic modelling of the maglev-based high-speed railway line in Shanghai, China. Focus is placed on an accurate simulation of the two subsystems: the train subsystem including the magnets and the viaduct subsystem including the modular function units of the rails. The electromagnet force–air gap model with a proportional-derivative (PD) controller is adopted to simulate the interaction between the maglev train via its electromagnets and the viaduct via its modular function units. The flexibilities of the rails, girders, piers and associated elastic bearings are all considered in the modelling of the viaduct subsystem to investigate their effects on an interaction between the two subsystems. By applying the proposed model to the Shanghai maglev line, the essential characteristics of the coupled system can be duly captured. The accuracy and effectiveness of the proposed approach are then validated by comparing the computed dynamic responses and frequencies with the measurement results. It is confirmed that the proposed modelling with a detailed simulation of the magnets and modular function units can duly account for the dynamic interaction between the train and viaduct systems. Moreover, the effects of the inclusion of the flexibilities of the rails, girders and elastic supports to the response of the coupled system are respectively investigated, the results of which prove that their involvements are essential to the accurate prediction of the response of the coupled maglev train–viaduct system.

The influence of inhomogeneous magnetic field over a NdFeB guideway on levitation force of the HTS bulk maglev system

Dynamic responses of high temperature superconducting bulk to inhomogeneous magnetic field distribution of permanent magnet guideway, as well as enlarged amplitude of magnetic field obtained by partially covering the permanent magnet guideway (PMG) with iron sheets in different thickness, are investigated. Experiments show that the instantaneous levitation force increases with the increase of the variation rate of magnetic field (dB/dt). Meanwhile, inhomogeneous magnetic field from PMG causes the decay of levitation force. The decay of levitation force almost increases linearly with the increase of alternating magnetic field amplitude. It should be very important for the application of high-speed maglev system.

Thermal effect on dynamic performance of high-speed maglev train/guideway system

Temperature fields and temperature deformations induced by time-varying solar radiation, shadow, and heat exchange are of great importance for the ride safety and quality of the maglev system. Accurate evaluations of their effects on the dynamic performances are necessary to avoid unexpected loss of service performance. This paper presents a numerical approach to determine temperature effects on the maglev train/guideway interaction system. Heat flux density and heat transfer coefficient of different components of a 25 m simply supported concrete guideway on Shanghai High-speed Maglev Commercial Operation Line is calculated, and an appropriate section mesh is used to consider the time-varying shadow on guideway surfaces. Based on the heat-stress coupled technology, temperature distributions and deformation fields of the guideway are then computed via Finite Element method. Combining guideway irregularities and thermal deformations as the external excitations, a numerical maglev train/guideway interaction model is proposed to analyze the temperature effect. The responses comparison including and excluding temperature effect indicates that the temperature deformation plays an important role in amplifying the response of a running maglev, and the parameter analysis results suggest that climatic and environmental factors significantly affect the temperature effects on the coupled maglev system.

Technological Development of High Speed Maglev System Based on Low Vacuum Pipeline

Technological Development of High Speed Maglev System Based on Low Vacuum Pipeline

Adjustable Squirrel-Cage Linear Induction Motor for Magnetic Levitation Transport

The article deals with linear induction motor (LIM) with a squirrel-cage winding of the secondary element (SE), which functions as the armature of the machine. Linear location of squirrel-cage winding of the secondary element of LIM allowed suggesting a number of options for the regulation of the winding resistance of SE. Objective. Development and research of LIM with adjustable winding resistance of the secondary element for magnetic levitation transport, and the study of the properties of adjustable LIM. At the modern level of development of the electrical engineering, asynchronous electric drive and magnetic levitation transport, the primary method of changing the frequency rotation of motor and speed of linear motion of high-speed transport vehicles is frequency control. Frequency control allows changing the frequency of rotation of the machine and linear speed of LIM smoothly and in broad diapason. The high cost of static electronic converters of high power limits the large-scale application of frequency control. The increase of the current frequency also leads to lower torque and traction. Results. According to the authors, the application of the adjustable linear induction motors with variable resistances of short-circuited windings of the secondary elements will allow to expand the range of control of LIM, intended for high-speed magnetic levitation transport with the realisation of large traction, including the start (starting the vehicle) by means of current displacement in the groove of the secondary element of the LIM. Conclusion. The linear induction motors of this type, as well as the calculation of the magnetic field in the groove of the secondary element, and evaluation of the influence of the current displacement on the starting and controlling features of the machine are considered.

Combination Traction and Lateral Stabilisation System for Magnetic Levitation Transport

The problems of improvement of modern types of transport and creation of new ones are important and topical for the human society development. One of the most promising and environmentally-friendly modes of transport is the high-speed maglev transport, moving at speeds of approximately 500 km/h. Objective. Justification of linear induction motor, development and research of various constructions of this type of motors. Methods. Description of linear induction motor with longitudinal and transverse magnetic flux for combined traction and lateral stabilisation system of maglev transport, having increased lateral stabilisation forces. The mathematical modelling of magnetomotive force (MF) in the air gap of traction linear motor of this type has been conducted. To analyse the MF the assumption has been made about even distribution of magnetic induction in the air gap in transverse direction and its sinusoidal longitudinal direction, making it possible to develop new mathematical model of MF distribution in the air gap of linear induction motor with longitudinal and transverse magnetic flux Results. The developed mathematical model for calculation of MF on traction linear machine will enable increasing accuracy of traction and lateral stabilisation combined system forces for maglev transport. The same relates to mutual location of inductor to the secondary element. All this proves the successful ten-year commercial operation experience of magnetically suspended train carrying passengers from an airport to Shanghai, P.R. China. The values of traction and lateral stabilisation forces of linear induction motor with longitudinal and transverse magnetic flux is greatly influenced by the character of current distribution in the secondary element. The character itself is influenced by MF distribution in the air gap.