Maglev Train Research Articles

Dynamic Interaction Analysis of High-Speed Maglev Train and Guideway with a Control Loop Failure

The fault of a control loop can occur when a high-speed maglev train is running on guideways, which will affect the dynamic responses of the maglev train and guideway and is one of the controlling cases in the design of guideway functional parts. To study the dynamic response of the vehicle and guideway when a control loop failure occurs, first, a spatial coupling vibration model, which includes the three-dimensional (3D) maglev trains, guideways, piers and electromagnetic force based on the proportional-derivative (PD) controller, is proposed, and the electromagnetic force model for a control loop failure is presented. Second, the effectiveness of the coupling vibration model is verified based on the measured results of the Shanghai maglev line (SML). Finally, the dynamic responses of maglev train and guideway are discussed under a suspension magnet or guidance magnet with a control loop failure, and the influences of the location of the fault, the weight of the vehicle and the preload of the guidance system are analyzed. The most disadvantageous load value acting on the functional parts in case of magnet failure is obtained. The results show that the dynamic responses of the maglev train with a control loop failure will vary due to the location of the fault on trains and guideways, the weight of vehicle and the lateral preload. Although a control loop failure has little influence on the dynamic response of the guideway, the suspension force or guidance force on guideway will increase suddenly, and this sudden force is far larger than the vehicle static load or lateral preload of guidance magnets.

Ground vibration induced by maglev trains running inside tunnel: Numerical modelling and experimental validation

Vibration induced by urban rail transit has been a growing public concern worldwide. In this context, medium-low speed maglev trains gradually stand out due to their environmentally-friendly advantages in vibration and noise control. However, few studies have investigated maglev train-induced vibration, and much uncertainty still exists about the environmental vibration caused by underground medium-low speed maglev trains. This paper presents a numerical study of train-induced vibration and proposes a hybrid prediction model based on vehicle-track spatially coupled dynamics in the 2.5D FE framework. This method could consider the nonlinear behaviour of the vehicle-track system in more detail, and the application of Green's function makes this method more efficient when dealing with multiple conditions. Moreover, field measurements are carried out on maglev train-track-embankment system, and measured data show good agreement with the prediction results in the time and frequency domain, verifying the accuracy of the proposed model. Numerical analysis is conducted for the vibration response of the vehicle-track-tunnel-soil system, which reveals the transmission behaviour of the maglev train-induced vibration in layered soils, along with the possible causes of vibration amplification phenomena disclosed. Finally, the vibration levels caused by the maglev and subway trains are compared to quantify their differences. Related results provide insights for unveiling the mechanism of impact brought by daily maglev trains on the neighbouring environment and the quality of residents living alongside.

Design and Levitation Performance above A Permanent Magnet in Maglev Train Prototype

Abstract Maglev trains have a working system that will later be used to move the train. Magnetic Levitation (maglev) working system uses the principle of attractive or repulsive force generated by magnets. In its development, there are several systems used on maglev trains. This article describes how to design the strength of the magnetic field in the maglev prototype. Tests using a magnet based on the distance and diameter of the magnet. The results of measuring the magnetic field on a permanent magnet by varying the space to determine the position of the largest magnetic field, where the largest magnetic field is found in 2 magnetic pieces with a diameter of 15 mm with a value of 50.7 gauss. In the coil magnet, manual calculations are carried out, to produce a magnetic field equal to 2 pieces of 15 mm diameter magnet requires a current of 10 amperes

Neural-Network-State-Observation-Based Adaptive Inversion Control Method of Maglev Train

Maglev train is a new vehicle of rail transit. The time-varying load caused by large capacity is an important test of suspension system. If the state variable matrix and parameter matrix caused by time-varying mass cannot be estimated effectively, it is very likely to lead to the decline of suspension performance and instability. Firstly, an NNs state observer based on neural network is proposed to effectively estimate the system state and parameter matrix. Secondly, based on the NNs observer model, an inverse control algorithm with stronger regulation ability is designed by integrating the output limited characteristics and Lyapunov function, which can ensure the stability of the system when disturbed. The simulation results show that the control algorithm proposed in this paper can have faster response speed and stability in the flotation process of 16mm-10mm, and has better anti-disturbance ability in the face of time-varying mass disturbance. Finally, based on the single point suspension experimental platform, the effectiveness and practicability of the proposed control algorithm are verified, and the correctness of the proposed NNs observer model is also verified.

High-speed magnetolevitatve land transport with power supply by distributed photoelectric energy system with perspective energy storage

Among the various types of high-speed land transport a magnetic levitation transport (magnetoplanes) is recognized as the most promising, so research related to the improvement of this type of transport is relevant. The work is devoted to the integra-tion of three promising research technologies: magnetolevitative transport, photoelec-tric energy conversion and phase-metric radionavigation. It is this integration, i.e. the essential interpenetration of these three subsystems, results in an overall synergistic ef-fect. Achieving the goals of sustainable development of the national economic complex within the framework of traditional transport and energy technologies is problematic, as energy consumption of transport systems exceeds one third of energy consumption, and the fastest mode of transport – an air transport is one of the leading air pollutants. Therefore, the purpose of this work is to substantiate a promising way to solve this problem by combining in a single system of renewable energy technologies and magne-tolevitative transport. The methods of system analysis and decomposition, statistical analysis of solar insolation, radiophysical experiment, computer modeling of photovol-taic energy converters, algorithmization of current control processes and forecasting the energy storage devices state are involved. The result of the research is the development of physical and technical bases for the improvement of magnetolevitative transport. Conclusion: by combining in a single system of renewable energy technologies and mag-netic levitation transport it is possible to create a system of all-weather guaranteed power supply based on solar energy and a reliable precision high-speed control system in real time.

The Hybrid Suspension System for Middle-to-Low-Speed Maglev Trains Considering the Prevention of Firm Absorption

The electromagnetic suspension system (EMSS) plays a critical role in providing attractive force for middle-to-low-speed maglev trains, which contains two critical components—an electromagnet and a steel track. However, with the acceleration of trains, the eddy current generated by the relative motion between the electromagnet and the track becomes intensified, which may directly weaken the attractive force. To maintain the suspension air gap between the iron yoke and the track stable, more current needs to be inserted into the winding of the electromagnet. The local thermal surge existing in the winding may appear due to the overloaded input current for long term, which may cause the insulation aging or even damage of the winding. If the short-circuit accident occurs between the neighboring turns of the winding due to the interturn insulating damage of the winding, the loss of suspension force tends to be deteriorated undoubtedly. In this article, a novel hybrid suspension system mixed electromagnetic and permanent magnetic modes is proposed for enhancing suspension force with economical power consumption. However, when applying permanent magnets for assisting electromagnets, the firm absorption (FA) phenomenon needs to be considered. Two suspension schemes with unequal-width and unequal-height iron yokes are launched for reducing FA risk. The corresponding finite element method (FEM) models have been built and verified by experimental results. The comparison of different suspension schemes under the dynamic condition with different relative velocities between the suspension module and the track has been undertaken in the end.

Numerical Analysis of the Rotational Magnetic Springs for EDS Maglev Train

Different from the traditional railway trains, the combined levitation and guidance EDS maglev train is more likely to rotate after being disturbed. Therefore, the rotational electromagnetic stiffnesses are significant operating parameters for the train. In this paper, the different effects of each translational offset generated in the rotational motion on the corresponding rotational electromagnetic stiffnesses in the EDS maglev train are analyzed and calculated. Firstly, a three-dimensional model of the maglev train is established. Then, based on the space harmonic method and the equivalent circuit of the levitation and guidance circuits, the formulas of rolling, pitching and yawing stiffness are presented. Finally, by comparing with the three-dimensional finite element simulation results, the key translational displacements in the rotational motion which has a great impact on the stiffness are obtained. Hence, the three-dimensional analytical formula can be simplified and the computation can be reduced. In addition, the accuracy of the calculation results is verified by comparing with the experimental data of Yamanashi test line.

Notice of Retraction: Three-dimensional Electromagnetic Characteristics Analysis of Novel Linear Synchronous Motor under Lateral and Yaw Conditions of MAGLEV

Dynamic stability analysis of superconducting electro-dynamic maglev train under lateral and yawing motion condition is the key research content. The novel three-dimensional electromagnetic model of integrated linear synchronous motor in electro-dynamic maglev train with yawing operation condition is proposed, which can not only simultaneously achieve the propulsion, levitation and guidance performances of maglev vehicle, but also analyze the dynamic stability performance of train with yawing condition. The three-dimensional analytical method is introduced for analyzing the electromagnetic force characteristics of the linear synchronous motor with the yawing operation condition. Firstly, the topology structure and operation principle of the linear synchronous motor with yawing attitude are proposed. Secondly, the three-dimensional analytical model and expressions of electromagnetic characteristics are obtained by equivalent circuit method and Fourier decomposition method, such as levitation force, guidance force, propulsion force and yawing torque, etc. Finally, the three-dimensional electromagnetic characteristics of the linear synchronous motor are calculated under yawing operation conditions of maglev train, and the correctness of the analytical theory is verified by the finite element analysis and measured data on the test line.

Discrete-Time Optimal Control of Double Integrators and its Application in Maglev Train

Discrete-Time Optimal Control of Double Integrators and its Application in Maglev Train

Experimental and Numerical Analyses of a Novel Wing-In-Ground Vehicle

The AeroCity is a new form of transportation concept that has been developed to provide high-speed ground transportation at a much lower cost than the existing high-speed railway. Utilizing the Wing-in-Ground (WIG) effect, the AeroCity vehicle does not require complex infrastructures like other contemporary concepts, such as the Hyperloop or Maglev trains. In the current work, the aerodynamic characteristics of the AeroCity vehicle are examined through a Computational Fluid Dynamics (CFD) analysis. The results from the CFD analysis qualitatively match with the findings of wind tunnel experiments. Surface streamlines and boundary layer measurements correspond well with the numerical data. However, the force measurements show a discrepancy. It is found that the separation bubble over the side plates is not captured by the CFD, and this is responsible for an under-prediction of the drag at higher free-stream velocities. The Transition SST model improved the matching between the experiments and numerical simulations. The influence of the moving ground is numerically investigated, and the effect of non-moving ground on the vehicle aerodynamics was found not to be significant. Finally, the inclusion of the track wall is examined. It is found that the merging of the wingtip vortices is responsible for a significant drag increase and, therefore, an alternative track geometry should be investigated.

The Effect of Concave Size on the Aerodynamics of a Maglev Train

The Effect of Concave Size on the Aerodynamics of a Maglev Train

A three-dimensional numerical model for evaluation of eddy current effects on electromagnetic forces of HTS electrodynamic suspension system

Magnetic levitation (Maglev) train has the advantages of high speed, low noise, low carbon emission and low operation costs, which meets the demands of future transportation systems. The high temperature superconducting (HTS) ElectroDynamic Suspension (EDS) system with on board HTS magnets and null-flux ground suspension coils is one of the most promising schemes for commercial operation. The numerical model of the electromagnetic forces in the HTS EDS system is well established through the dynamic circuit approach. However some realistic behavior including the eddy current induced in the metal vessel cannot be easily described as simple circuit components like a coil. The analysis of these issues is easier with a finite element method (FEM). In this paper, a three-dimensional FEM model is built to simulate the electromagnetic behavior of the null-flux coils – HTS magnet mechanism in motion. Especially, the electromagnetic interaction forces between the ground null-flux coils and HTS magnets mechanism are studied. Moreover, effects of framed vessel structures on electromagnetic forces of the HTS EDS system is discussed.

Verification of numerical model of hybrid EMS using test bench measurements at large air gap

Aim: The study was focused on measurement of the lifting force of a hybrid EMS (HEMS) prototype. The measured data were used to verify numerical models.
 Materials and Methods: Measurements were performed on a certified test bench at a large air gap (13 mm, 17 mm). The measured data were compared with results of numerical experiments.
 Results: A comparison of measured and simulated parameters have proved reliability of numerical models.
 Conclusions: A prototype of HEMS for maglev transport has been built and bench tested at JSC NIIEFA. The results obtained will be used to establish measurement, prototyping, and inspection procedures for series production.

Track Defect Detection for High-Speed Maglev Trains via Deep Learning

The high-speed maglev train is a new type of transportation. The long stator track plays a critical role in the levitation guidance and traction system. Therefore, its condition directly affects the operation of maglev trains. It is extremely important to detect the abnormal condition of high-speed maglev tracks to ensure the stable, safe, and reliable operation of the train. In this article, an onboard image detection system is designed for high-speed maglev tracks, which can accurately obtain the image of long stator tracks under the harsh conditions of limited installation space, insufficient illumination, and rapid operation of vehicles. High-speed maglev trains are not yet in widespread use. In China, there is currently only one demonstration operating line located in Shanghai, and the length of the track test line is limited. Therefore, the number of track images that can be acquired is extremely limited. In view of the lack of defective samples of high-speed maglev tracks, this article proposes a data enhancement method based on sample generation and image fusion to augment the dataset of defective samples. To improve the quality of generated high-speed maglev track defect images, a joint attention layer (JEA) combining squeeze-and-exception (SE) block and spatial attention module (SAM) is designed and introduced into the generative adversarial network (GAN). This work provides a data basis for the study of track defect detection of high-speed maglev trains. In addition, this article detects the defects of high-speed maglev tracks via deep learning-based target detection algorithms, which can automatically detect, accurately classify and locate the defects of stator surface and cables, filling the gap in the field of high-speed maglev track defect detection.

A Numerical Method for Determining Critical Current of ReBCO Coils: Modelling Details, Validation, and Comparison with T-A-Formulation

High temperature superconductor (HTS) coils have been applied in high field magnet applications, such as nuclear magnetic resonance (NMR) and maglev trains. The accurate calculation on the critical current of HTS coils is key for the magnet design and optimization. An effective way to calculate the critical current of HTS coils is the quasi-critical state model based on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T-A</i> formulation and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E-J</i> power law, which works well in 2D models, but suffers from hard convergence and huge computations in 3D models. A simple way of critical current calculation is to use a magnetic field model based on uniform current assumption. This improved model avoids solving highly-nonlinear equations and the calculation cost is greatly reduced, thus can be a more practical solution for the critical current estimation of HTS coils with complex geometry. This paper studies and compares critical current of circular and racetrack HTS coils, the critical current of each coil is calculated by <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T-A</i> model and the improved uniform current model. Results from the uniform current model shows consistency with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T-A</i> model with a discrepancy lower than 5% for most cases. This paper aims to provide a simple and fast modelling method for the critical current estimation with enough accuracy for HTS coils.

Feasibility Analysis of Vacuum Pipeline Magnetic Levitation Energy Storage System Based on Existing Magnetic Levitation Transportation Technology

This paper is mainly summarized the research progress of maglev transportation technology. The vacuum pipeline magnetic levitation energy storage system is constructed based on the existing four types of magnetic levitation as technical prototypes, and the four schemes are formed: as followed: electromagnetic suspension (EMS) medium and low speed magnetic levitation type vacuum pipeline energy storage system, EMS high speed magnetic levitation type vacuum pipeline energy storage system, electric suspension (EDS) high speed magnetic levitation type vacuum pipeline energy storage system and super high-speed rail type vacuum pipeline energy storage system. The energy storage and energy storage cost of these four energy storage systems are analyzed to study their energy storage feasibility.

Optimisation of input power in linear induction motor (LIM) based Maglev vehicle

Maglev or magnetic levitation is an advanced technology in the modern world for high speed trains. The magnetically levitated train has no wheels, but floats on an electromagnetic wave. Maglev train system uses magnetic forces to levitate, guide and to propel the vehicle and the technology behind it enamored many countries worldwide. Different techniques have been proposed by the researchers, and a number of corridors have been selected and surveyed. This paper, describes a separate type of magnetically levitated train working model based on Linear Induction Motor (LIM) and permanent magnet. In this paper, the LIM is divided into three sections and the complete system performance is analyzed.

Tunable flux-jump characteristic of multifilamentary composite Nb&lt;sub&gt;3&lt;/sub&gt;Sn superconducting wires in maglev systems

The superconducting solenoid with constant large current is exposed to an alternating magnetic field during the acceleration of the superconducting maglev train, which will cause flux jump of the superconducting solenoid. It can reduce the current-carrying capacity of the solenoid, and generate a lot of heat and make the temperature of the superconducting solenoid rise sharply, which will make the whole superconducting coils quenched. Thus the research of flux jump has very important scientific significance. Nb&lt;sub&gt;3&lt;/sub&gt;Sn superconducting wire is a composite structure composed of multiple superconducting filaments、copper and epoxy resin. In this paper, the magneto-thermal instability behavior of a three-dimensional superconducting wires under alternating magnetic fields and constant current is studied by using a two-dimensional model in which the net current of each filament is constrained to zero. By analyzing the effect of amplitude and frequency of alternating magnetic field on flux jump of a Nb&lt;sub&gt;3&lt;/sub&gt;Sn superconducting wire, we find that when the magnetic field amplitude keeps unchanged, the magnetic field threshold of the initial flux jump changes non-monotonically with the frequency. While the frequency keeps unchanged, the threshold of the initial flux jump changes monotonously with the amplitude of the alternating magnetic field. In addition, with the decreasing applied field, the frequency range for flux jump first increases then decreases to certain critical frequency when the superconducting wire does not have flux jumps. The results of this paper can provide a theoretical basis for regulating the magneto-thermal instability of superconducting wires.

Prospects for the use of Maglev trains in Azerbaijan

Prospects for the use of Maglev trains in Azerbaijan

Vibration analysis and multi-state feedback control of maglev vehicle-guideway coupling system

&lt;abstract&gt; &lt;p&gt;Due to the existence of elastic modes in the track, the suspension system of maglev train is prone to vehicle-track coupling vibration, which has become an important problem restricting the further development of maglev train technology. In view of the limitation of the existing rigid track suspension model, this paper establishes an electromagnet-controller-elastic track coupling system model. And then, the nonlinear maglev system is transformed into a linear system by Hartman-Grobman theorem. Since the elastic deformation of the track is difficult to measure, a tracking differentiator is presented to filter out the interference of the displacement signal and obtain the differential signal of the gap between the electromagnet and the track. In order to suppress the vehicle-track coupling vibration, a four-state feedback control method is proposed by introducing the gap differential feedback signal. According to the Hurwitz algebraic criterion, the stability of four-state feedback control system is compared with that of three-state feedback control system. Simulation results show that, the four-state feedback control method can provide the elastic deformation information of the track, and can suppress the coupling vibration between the vehicle and the elastic track effectively.&lt;/p&gt; &lt;/abstract&gt;