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The concept of Inductrack refers to the magnetic levitation technology achieved by Halbach arrays of permanent magnets. In an Inductrack system, the dynamic behaviors involved with transient responses are difficult to capture due to the highly nonlinear, time-varying, electromagnetic-mechanical couplings. In the literature, dynamic modeling of Inductrack systems that aims to analyze the transient behaviors has been widely addressed. However, one common issue with the previous investigations is that most of the dynamic models either partly or completely adopted certain steady-state and ideal case assumptions. These assumptions are extremely difficult to maintain in a transient scenario, if not impossible. Therefore, while providing good understanding of Inductrack systems, the previous results in dynamic modeling have a limited utility in providing guidance for feedback control of Inductrack systems. Recently, a benchmark transient Inductrack model was created for characterizing the transient time response of the system with fidelity, which enables model-based feedback control design. In this work, based on the transient model, a new control method for the Inductrack dynamic system is developed. The proposed control method consists of a linear part and a nonlinear part. The linear part is devised based on a state feedback configuration; the nonlinear part is accomplished by fitting a nonlinear “force-current” mapping function. With this nonlinear feedback controller, the levitation gap of the Inductrack vehicle can be effectively stabilized at both constant and time-dependent traveling speed. The proposed control law is demonstrated in numerical examples. The nonlinear control design is potentially extensible to more complicated Inductrack systems with higher degrees of freedom.

As a new strategy for magnetic levitation envisioned in 1990s, the Inductrack system with permanent magnets (PMs) aligned in Halbach arrays has been intensively studied and applied in many projects. Due to the nonlinear, time-varying electro-magneto-mechanical coupling in such a system, the dynamic behaviors are complicated with transient responses, which in most cases can hardly be predicted with fidelity by a steady-state Inductrack model. Presented in this paper is a benchmark 2-DOF transient Inductrack model, which is derived from the first laws of nature, without any assumed steady-state quantities. It is shown that the dynamic response of the Inductrack dynamic system is governed by a set of nonlinear integro-differential equations. As demonstrated in numerical simulations with the transient model, unstable vibrations in the levitation direction occur when the traveling speed of the vehicle exceeds a threshold. To resolve this instability issue, feedback control is implemented in the Inductrack system. In the development, an assembly of Halbach arrays and active coils that are wound on the PMs is proposed to achieve a controllable source magnetic field. In this preliminary investigation, the proposed control system design process takes two main steps. First, a PID controller is set and tuned based on a simple lumped-mass dynamic system. Second, the nonlinear force-current correlation is obtained from a lookup table that is pre-calculated by steady-state truncation of the full transient Inductrack model. With the implemented feedback control algorithms, numerical examples display that the motion of the vehicle in levitation direction can be effectively stabilized at different traveling speeds. Although only a 2-DOF transient model is used here, the modeling technique and the controller design approach developed in this work are potentially applicable to more complicated models of Inductrack Maglev systems.

As a new strategy for magnetic levitation envisioned in the 1990s, the Inductrack system with Halbach arrays of permanent magnets has been intensively researched. The previous investigations discovered that an uncontrolled Inductrack system may be unstable even if the vehicle travels well below its operating speed and that instability can be persistent near and beyond the operating speed. It is therefore necessary to stabilize the system for safety and reliability. With strong nonlinearities and complicated electromagneto-mechanical coupling, however, the transient response of such a dynamic system is difficult to predict with fidelity. Because of this, model-based feedback control of Inductrack systems has not been well addressed. In this paper, by taking advantage of a recently available two degrees-of-freedom transient model, a new feedback control method for Inductrack systems is proposed. In the control system development, active Halbach arrays are used as an actuator, and a feedback control law, which combines a properly tuned proportional-integral-derivative controller and a nonlinear force-current mapping function, is created. The proposed control law is validated in numerical examples, where the transient motion of an Inductrack vehicle traveling at constant speeds is considered. As shown in the simulation, the control law efficiently stabilizes the Inductrack system in a wide range of operating speed, and in the meantime, it renders a smooth system output (real-time levitation gap) with fast convergence to any prescribed reference step input (desired levitation gap).

In the past years, different superconducting levitation systems were developed around the world. Most projects focused on optimizing the flux density in the working space of the superconductor in order to maximize the levitation force of the system. In general, these systems use tracks with permanent magnetic Halbach arrays or combine permanent magnets with steel yokes to maximize the usable flux density. Therefore, none of these tracks can easily be switched off to allow a safe crossing or to build a fast turnout switch without moving parts. A new track was designed containing permanent magnets and a YBCO-tape-coil to realize a fast switchable track. In this concept, the permanent magnets provide the flux used for levitation, whereas the coil controls the flux in the space above the track, where levitation usually takes place. The magnetic behavior of this new design was studied and improved with two-dimensional (2-D) and 3-D simulations. Afterwards, a demonstrator was built on which the induced magnetic field was measured in the different operation modes. The results of the measurements and the simulations indicate that the flux density above of the track might be controlled by the coil current. It was proven that the new track design generates magnetic fields comparable to the standard permanent magnetic track, whereas only residual fields are measured in inactive mode, which can be further reduced with negative coil currents.

In Part I of this two-part paper, a new benchmark transient model of Inductrack systems is developed. In this Part II, the proposed model, which is governed by a set of non-linear integro-differential governing equations, is used to predict the dynamic response of Inductrack systems. In the development, a state-space representation of the non-linear governing equations is established and a numerical procedure with a specific moving circuit window for transient solutions is designed. The dynamic analysis of Inductrack systems with the proposed model has two major tasks. First, the proposed model is validated through comparison with the noted steady-state results in the literature. Second, the transient response of an Inductrack system is simulated and analyzed in several typical dynamic scenarios. The steady-state response results predicted by the new model agree with those obtained in the previous studies. On the other hand, the transient response simulation results reveal that an ideal steady-state response can hardly exist in those investigated dynamic scenarios. It is believed that the newly developed transient model provides a useful tool for dynamic analysis of Inductrack systems and for in-depth understanding of the complicated electro-magneto-mechanical interactions in this type of dynamic systems.

As a new approach to magnetic levitation by permanent magnet envisioned in 1990s, the concept of Inductrack has been applied to designs of various Maglev systems, including rocket launchers, Maglev trains, and the Hyperloop system as a conceptual future transportation tool. In such a system, the interaction forces between the source and induced magnetic fields are motion-coupled, and inevitably complicated with transient responses. Most previous investigations have mainly relied on the assumptions of ideal magnetic field, steady-state response and averaged magnetic force. Although these analyses provide some useful information for system design, due to limited understanding of the magnetic field-motion coupling and transient responses, they cannot predict the dynamic behaviors of an Inductrack system with fidelity and accuracy. Presented in this paper is a new transient model of Inductrack dynamic systems that is derived from fundamental physics laws, with the interactions of magnetic forces and motion in consideration. In the development, a state space representation of the transient model is established for numerical simulations. As verified in numerical examples, a benchmark 2-DOF transient model not only is able to reproduce the “steady-state” results reported in the literature, but also can exhibit the transient behaviors of Inductrack systems in longitudinal and vertical motion, which otherwise may not be possible by the existing models. The modeling approach presented in this paper is extendible to multi-degree-of-freedom (M-DOF) cases and it provides a foundation for stability analyses and feedback control of Inductrack systems.

The levitation force between a permanent magnet (PM) and a high-temperature superconductor (HTS) bulk has resulted in various industrial applications. PMs’ volume has a substantial role in the cost of PM guideways (PMGs), especially for long-distance transportation, which necessitates the optimum arrangement for PMs. Halbach array has proved considerable levitation force because of its one-sided magnetic field among the other known arrangements. In this paper, a variety of Halbach PMG structures with varying PM magnetization angles are simulated and the impact of PM angular magnetizations on the levitation force is investigated. A heuristic method has been proposed to acquire the optimum magnetization angles that maximize the levitation force. This optimum design decreases the total cost due to the minimum PM use besides providing a satisfactory stable levitation for a specified levitation height, PMG width, and HTS disk’s characteristics. Prototypes have been developed based on the optimized PMG designs with the satisfactory results, compatible with the analytical and simulation results.

This paper describes the levitation and guidance characteristics of a semi-high-speed magnetic levitation (MAGLEV) vehicle. For a MAGLEV, which operates at 200 km/h, the guidance magnet is essential for high-speed operation at curves and against a side wind. The levitation and guidance magnets are electromagnetically and dynamically coupled, because both are used in a single rail. Because of the interactions between the levitation and guidance systems, clear establishment of their correlation is required for robust and stable control. We identify the electromagnetic/dynamic correlation of the levitation and guidance systems of the MAGLEV using a magnetic equivalent circuit and motion equations. A controller is developed to realize stable control by considering the system correlation. The control properties are obtained through simulation to achieve stable levitation and guidance.

We studied a magnetic levitation system that uses the magnetic shielding effect of high-temperature superconductor (HTS) bulks. The basic model in our system is composed of a ferromagnetic rail, HTS bulks, and a permanent magnet. To increase the levitation force in the system, we used three basic models and proposed some modified models that featured different arrangements of the three basic models. The modified models were the parallel model, common-rail (NSN) model, and common-rail (SSS) model. First, we explained the three kinds of modified models and then showed the measured levitation forces of these models. The experimental results indicated that the maximum levitation force was 1588 g for the common-rail (NSN) model, 1064 g for the common-rail (SSS) model, and 976 g for the parallel model. The strongest levitation force of the common-rail (NSN) model was more than seven times greater than the maximum levitation force of the basic model.

A passive magnetic levitation (maglev) carrier is a transportation device that is based on magnetic levitation and does not have any electric circuits on the moving part. Because the actuation devices are not in the moving platform for passive operation, the levitation forces are non-homogenous. This characteristic makes the design and control of the system challenging. We present design and control procedures for a passive maglev carrier system. To achieve stable and accurate levitation, mechanical analyses were performed to determine the configuration and locations of the levitation magnets. The key challenge in the control design is that the locations and magnitudes of the levitation forces are not continuous around the edge of the moving platform when it passes the magnet. Therefore, the longitudinal positions of the magnets relative to the moving platform are a noise (uncontrollable) factor for the controller. The control parameters should be robust against the noise factor to achieve reliable performance. The Taguchi method was used to determine the optimal control parameters in the presence of the noise factor. The optimized gain reduced the position variation of the levitated carrier by 50% in terms of the root mean square error.

The article presents the results of the prototype magneto-levitation bogie for the transport of containers using the technology of magneto-dynamic levitation «Inductrack». The main elements of the prototype bogie are: - supporting welded steel frame, which is attached to the container stops, blocks, magnets, support and guide wheels; - the magnets are combined into blocks according to the scheme «an Array of Halbach»; - shunting wheel required for pre-acceleration of the bogie (with levitation wheels not touching the track structure); - guide wheels, which serve for centering the bogie on the road when driving on a plot of acceleration. Cart design was developed taking into account the possibility of placing massive superconductors instead of permanent magnets. Carts are designed to carry containers of various types, it does not require additional devices for connecting the carriages together. To assess the strength of the construction was taken following calculation modes: - the moving bogie, when you turn on linear synchronous motor, a trolley supported by shunting wheel and operate the inertial load; - braking when the bogie is in magneto-levitation flight support with the maneuvering of the wheel is missing, there are inertial load; - support bogie magnets on when the bogie is in magneto-levitation flight; - support the trolley on the shunting wheel, the linear synchronous motor is turned off. The calculation was carried out by finite element method using the design package «Ansys Workbench».

A Maglev car travels by floating on a magnetic track with the attractive and repulsive force of magnets to create both lift and propulsion. The paper presents outlines of an application on magnetic levitation transportation technology to design a new car and study of it utilizing computer vision. This vehicle is specially designed to give high comfort to the physically challenged people and to move in a profoundly secure condition. The vehicle is planned with a full resting beds compartment and can move at a very high speed. Inductrack a frictionless, attractive levitation framework is proposed to be used here for super speeds. It offers a smooth contactless trip to the goal. Helper components are just required when the vehicle needs to back off and needs to stop at a station. The financially savvy Halbach arrays of magnets are utilized to produce high magnetic fields to suspend and move the vehicle. Computer animation of the whole circumstance shows up and observed it to be a good vehicle with high speed. Computer vision system study is utilized to detect cars, monitoring vehicle, analysis of car video information for a safe journey, and to avoid accidents. Tracking a car in a vulnerable environment is difficult due to noise generation. To overcome this problem, a method is proposed for noise removal from the car videos for tracking it in a vulnerable environment. It is found that the proposed methods give better result compared to the existing one. Thus, it shows that computer vision can greatly help the Maglev vehicle to provide more safety, high alerts, and high comfort to the passengers.

The EMS (Electro-Magnetic Suspension) maglev train uses attractive magnetic forces to neutralize its weight, which puts a rather high requirement on the smoothness of the track since the levitation gap is generally 8∼10 mm. It has been observed that in a traveling urban maglev train, the levitation gap error of the rear levitation unit in a levitation module is generally more prominent than that of the front levitation units; and under poor track conditions, the rear electromagnet of the levitation unit is more likely to clash with the track and to cause a levitation failure. However, this phenomenon has not yet been well interpreted. In this paper, a model of the levitation module in a maglev train is built to study the responses of the levitation gaps under different vehicle speed and track conditions, and results show that the levitation module is sensitive to some specified wavelengths of the track irregularities, and the analysis well interprets the reason that causes the difference of the response for the front and the rear levitation unit under track irregularities. A control strategy is also proposed to reduce the rear gap fluctuation.

In this study, the noncontact magnetic levitation system using combined high temperature superconducting (HTS) bulk annuli and ring-shaped permanent magnet (PM) was proposed. In the suggested levitation system, the HTS bulk annuli were magnetized by ring-shaped PMs fixed between the HTS bulk annuli, so there was no more need to apply source for magnetization. In this paper, the levitation forces on the radial and axial directions were measured using 1 PM + 2 bulks (1 unit) and 2 PM + 3 bulks systems to study the optimization of levitation system. To improve the levitation property of proposed levitation system, the shape of PM and materials of the rotor shaft were studied experimentally.

We studied a magnetic levitation system using the magnetic shielding effect of a GdBCO bulk superconductor. One set of permanent magnet, ferromagnetic rail, and HTS bulk is called the basic model. To increase the magnetic levitation force, we place two basic models side by side. There are two kinds of models. The first has the S poles of the permanent magnets in both modules on the upper side and is named the 2-set (SS) model. The second has the S pole on the upper side of the permanent magnet and the N pole on the upper side of the other permanent magnet, and is called the 2-set (SN) model. The levitation force of the 2-set (SS) and (SN) models was more than twice that of the basic model. To support the experimental approach, we numerically evaluate a magnetic flux distribution using finite element method software.

A levitation configuration is reported wherein diamagnetic levitation, weight compensated diamagnetic levitation and diamagnetically stabilised levitation are combined. The configuration allows the simultaneous inline triple levitation of three different bodies without the need of energy input or feedback control. The proposed levitation setup could find application in sensitive multi-range seismometers or accelerometers wherein levitating seismic bodies with different masses and resonance behaviour are needed.

A small superconducting maglev propeller system, a small spacecraft model suspending and moving around a terrestrial globe, several small maglev vehicle models and a magnetic circuit converter have been designed and constructed. The track was paved by NdFeB magnets, the arrangement of the magnets made us easy to get a uniform distribution of magnetic field along the length direction of the track and a high magnetic field gradient in the lateral direction. When the YBCO bulks mounted inside the vehicle models or spacecraft model was field cooled to LN 2 temperature at a certain distance away from the track, they could be automatically floating over and moving along the track without any obvious friction. The models can be used as experimental or demonstration devices for the magnetic levitation applications.

It has been investigated that the interaction force in hybrid magnetic levitation systems with a GdBCO bulk superconductor and a permanent magnet system and two permanent magnets (PM2) and two cubic permanent magnets (PM3) system in their coaxial configuration at liquid nitrogen temperature. A single-domain GdBCO sample is of 20mm and 10mm in thickness, the permanent magnet PM1 is of rectangular parallelepiped shape, the permanent magnets PM2 and PM3 are of cubic shape; the system placed on the middle of system and their coaxial configuration; It is found that the maximum levitation force decreases from 46.3N to 16.3N while the horizontal distance (Dpp) between the rectangle permanent magnet and two cubic permanent magnets (PM2) is increased from 0mm to 24mm and the horizontal distance (Dsp) between a GdBCO bulk superconductor and two cubic permanent magnets (PM3) is 0mm, The results indicate that the higher levitation force can be obtained by introducing PM-PM levitation system based on scientific and reasonable design of the hybrid magnetic levitation system, which is helpful for designing and constructing superconducting magnetic levitation systems.

A design for a passive magnetic bearing system that can stably levitate a rotor in all directions is described. The bearing system consists of levitation magnets coupled with a Halbach array stabilizer, which induces currents in stabilization coils, in order to overcome the inherent instability of a system composed only of permanent magnets. The levitation magnet system consists of two pairs of annular ring magnets which provide an upward magnetic levitation force to counteract the downward gravitational force of the rotor. The Halbach array stabilizer consists of two stabilization coils shifted in angular position with respect to one another and centered in the vertical direction between two rotating Halbach arrays. Magnetic fields from permanent magnets are calculated using superposition of fields due to patches of magnetization charge at surfaces where the magnetization is discontinuous. Induced currents in the stabilization coils are calculated by computing the time derivative of the magnetic flux through those coils. Magnetic forces on the rotor are computed using a superposition of forces on each patch of magnetization charge. The entire magnetic bearing system, consisting of both the levitation magnets and the Halbach array stabilizer, is stable to both vertical and lateral displacements. Results are compared with a simpler straightened approximation of the Halbach array stabilizer.

This paper proposes an analytical levitation force computation method using the equivalent magnetic circuit (EMC) of a controlled-permanent magnet (CPM) levitation system that has potential applications in a magnetically levitated vehicles. The airgap field and levitation force characteristics of the CPM are investigated using the EMC, considering airgap fringing and leakage flux path for longitudinal and lateral direction surfaces. The computation results are validated using finite-element analysis and experimental results. The levitation performance was tested using a dynamic force test facility, which confirms the validity of the EMC computation scheme for the description of a CPM levitation system.

The Laboratory for Applied Superconductivity of the Federal University of Rio de Janeiro (LASUP) has been developing a superconducting magnetic levitation urban train named MagLev-Cobra. It is a kind of light rail vehicle where the conventional wheel-rail track is substituted by a rail of Ne-Fe-B magnets and carbon steel interacting with superconductor bulks installed in the vehicle to promote levitation. The main cost of this levitation system is the magnetic rail. Therefore, any improvement in the shape and configuration of magnets and iron has a significant budgetary impact. In this paper, the optimizations carried out with the feasible direction interior point algorithm, extensive search, and genetic algorithm of magnetic rails are presented. The objective is to find the geometry that minimizes the total cost, for a given levitation force, considering some practical restrictions. The levitation force restriction is calculated using a finite-element method. During the optimization process, the superconductor null permeability model is used. Finally, the results are checked with the Bean model and verified experimentally. Measurements of the levitation force and the field mapped over the magnetic rails are presented. Significant reduction of soft and hard ferromagnetic materials was reached.

In this paper we analyse the behaviour of a small-scale model of a magnetic levitation system based on the Inductrack concept. Drag and lift forces acting on our prototype, moving above a continuous copper track, are studied analytically following a simple low-speed approach. The experimental results are in good agreement with the theoretical calculations. 3D-numerical simulations are also used to highlight the significance of the edge effects and to extrapolate the results to higher speeds.

The gradeability is one of the advantages of the high-temperature superconducting (HTS) maglev vehicle, and it is relative to the levitation characteristic of the maglev system on the ramp. The influence of the ramp angle on the levitation characteristics of the HTS maglev model was investigated. Some levitation characteristic parameters on the uphill guideway with different ramp angles were studied by the equivalent experiment, such as the levitation force, the levitation gap, the levitation stiffness and the guidance force. Compared with the experimental results on the horizontal guideway, it was found that the levitation gap increased, but the levitation force and the levitation stiffness decreased. The levitation gap and the levitation stiffness are considered as the main maglev characteristic parameters needed to be taken into account.

Typically, three types of levitation technologies are applied to magnetic levitation systems: electromagnetic suspension, electrodynamic suspension, and hybrid electromagnetic suspension. A Halbach array is a special arrangement of permanent magnets which augments the magnetic field on one side of the device while cancelling the field to near zero on the other side. The application of this Halbach array magnet to the electrodynamic suspension has been recently studied in order to increase the levitation capability. This paper is focused on an analytical method of the magnetic levitation system using Halbach array magnet. The suitability of the proposed method is verified with comparing to the finite element method. In addition, dynamic stability of the magnetic levitation system is discussed. From this study, it is confirmed that the proposed method provides a reasonable solution with less computation time compared to the finite element method and the magnetic levitation system using Halbach array magnet is stable dynamically.

Magnetic levitation, maglev, or magnetic suspension is a method by which an object is suspended with no support other than magnetic fields. This project describes the design procedure, analysis, and control of a single actuator magnetic levitation system. First the details of the system design and construction are presented, followed by an analysis of the relevant sub-systems and controller theory. Experimental levitation data is collected and compared to the theory. Utilizing a phase lead-lag controller, the goal is to investigate magnetic levitation and to design a working system capable of levitating an object without any form of support, maglev system is made stable for the levitation of a steel ball. Despite the simplicity and low cost of the position sensing system, it is able to detect the ball position. The successful operation of this system made of relatively low cost, low precision components reveals that compact, cheap, integrated magnetic levitation systems are becoming more feasible for a variety of applications with the increasing availability of new materials and faster, cheaper computer processing power.

By translationally moving a magnetic source above a conductive plate guideway both levitation and drag forces are created. Unfortunately, the electrodynamic drag force can be quite high [1]. Kratz studied a double Halbach array topology, such as shown in Fig 1 [1], and used a simple curve fitting approximation to model the forces. Kratz experimentally showed that a significant reduction in drag force can be created when using this “null current” approach. Much earlier Urankar derived analytic equations for a similar double coil system [2].

A pinning-type superconducting magnetic levitation guide with bulk high-Tc superconductors was studied for use as a goods transportation system, an energy storage system, etc. A superconducting magnetic levitation running test apparatus with a circular track of ca. 38 m length, 12 m diameter, which comprises the magnetic rail constituted by Nd-B-Fe rare-earth permanent magnets and steel plates, was manufactured to examine loss and high-speed performance of the magnetic levitation guide. Running tests were conducted in air. These tests clarify that a vehicle supported by a superconducting magnetic levitation guide runs stably at speeds greater than 42 km/h above the circular track.

Worldwide high speed Maglev (> 400km/h) developments refer to Maglev such as the Japanese JR-Maglev MLX, the German Transrapid and the USA Inductrack Maglev. Other world projects exist such as the Japan HSST ( 400km/h). The authors investigate new possibilities to combine both the propulsion and the levitation. In order to minimize the heat due to the motor levitation and guidance losses, a polarized excitation is proposed. The use of permanent magnet NdFeB for the excitation is still not applied for high speed Maglev, requiring mechanical power greater than 6MW. Such a solution only appears in Urban Rapid Transit Maglev (

A magnetically levitated (MAGLEV) vehicle using electromagnets and iron rails generates lateral guiding force naturally by controlling levitation force to maintain the air gaps between the magnets and the iron rails. A MAGLEV system without guide magnets offers simple design and cost advantages. But such a system has little lateral damping force. In order to improve damping characteristics, an experimental apparatus using salient-pole-type magnets and laminated iron rails was made. The iron cores were placed in two rows. The suspension coils surrounded both of the magnet iron cores and the damping coils surrounded every magnet core separately. The damping coils were excited by currents proportional to the lateral displacement velocity. According to a step response experiment, the lateral motion dissipated after a cycle or two of the swing. The self-inductance of the suspension coil of the magnet was almost unchanged against variation of the lateral displacement. The influence of damping current on the levitation was very small. This paper discusses the electromagnetic characteristics of the levitation system. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 71–80, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20372

A new type of magnetic levitation system called the Inductrack has been proposed by R. F. Post. This system is composed of a special arrangement of permanent magnets on board which is called the Halbach array, and a close-packed array of shorted coils in the longitudinal direction on the ground. This composition can obtain a large magnetic force, a very low take-off speed, and a high lift-to-drag ratio. This paper describes numerical simulations of the Inductrack magnetic levitation by the Fourier series analysis which is utilized in the analysis of superconducting magnetic levitation. By using numerical examples considering a full-scale car model, we reveal the features of the Inductrack system in comparison with the superconducting magnetic levitation. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 67–74, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10061

This papers presents technology aspects and choices relative to worldwide MAGLEV projects such as the German Transrapid, the Japanese MLX, the USA Inductrack and the Swissmetro. Propulsion, magnetic levitation and guidance, transfer of energy to the vehicle are investigated.

In this paper, a novel cylindrical magnetic levitation gravity compensator is proposed, of which the mover is composed of several permanent magnet rings in the arrangement of Halbach structure and the stator is composed of one permanent magnet ring and four copper coils. The new vacuum compatible gravity compensator can be applied to the 6-DOF high precision magnetic levitation stage as the vibration isolation and leveling device. Firstly, the analytical model of the magnetic levitation gravity compensator is established. The flux density distribution of the Halbach magnet array rings is obtained by using equivalent current model. Then the expressions of magnetic levitation forces and vertical stiffness are derived. Secondly, finite element method (FEM) is used to calculate the magnetic levitation forces in order to verify the analytical model. The results from FEM are in good agreement with the ones from analytical model, which indicates that the analytical model is accurate and reasonable. In addition, a cooling system for the magnetic levitation gravity compensator is designed and the thermal field of stator part is calculated. Last, the temperature rise experiment is achieved.

This paper aims at Design, Fabrication and Control of a single actuator magnetic levitation system. A physical design model of Magnetic Levitation System have been presented at the initial phase. Modeling and Simulation of this non-linear magnetic levitation system is proposed with feedback linearization where a non linear state space transformation is used to linearize the system exactly. After this, experimental setup and construction of actual magnetic levitation system is presented. Experimental Levitation data is collected and compared to the theory. Magnetic levitation system considered in this study is taken as a neodymium magnet suspended in a voltage controlled magnetic field. Dynamic behavior of the system was modeled by the study of electromagnetic and mechanical subsystems. State space model was derived from the system equations. For high accuracy in position detection, Hall effect sensor SS49E was utilized. The successful operation of this system was obtained using relatively cheaper and simpler magnetic levitation subsystems and components.

A new type of magnetic levitation system called the Inductrack, has been proposed by R F. Post. This system is composed of a special arrangement of permanent magnets on board which is called the Halbach array, and a close-packed array of shorted coils in the longitudinal direction on the ground. This composition can obtain a large magnetic force, a very low take-off speed and a high lift-to-drag ratio. This paper describes numerical simulations of the Inductrack magnetic levitation by the Fourier series analysis which is utilized in the analysis of superconducting magnetic levitation. By using numerical examples considering a full-scale car model, we reveal the features of the Inductrack system in comparison with the superconducting magnetic levitation.

Magnetic Levitation Transport system is suspended by magnetic levitation, and it is therefore basically free of contact parts that produce dust particles by friction. In order to take advantage of this no-dust characteristic, a number of magnetic levitation systems are currently being developed as transport systems for use in semiconductor manufacturing processes.The authors proposed the development of a new magnetic levitation system using a linear induction motor. Although the magnetic levitation characteristic was stabilized successfully, the moving control was complicated because the moving speed is dependent on the frequency of the commercial-frequency power supply. The present paper proposes the moving control of an AC attraction-type magnetic levitation transport system using a two-phase linear motor. The present system uses a low-frequency two-phase sinusoidal power supply amplitude-modulated from the commercial-frequency power supply. The levitation force is generated and controlled by a commercial-frequency AC magnetic field. In order to control the moving of the system, a low-modulation frequency control method is adopted.

Arising out of research at the Lawrence Livermore National Laboratory on passive magnetic bearings, a new magnetic levitation system, the Inductrack, has been developed and tested at model scale. The system employs special arrays of permanent magnets (Halbach arrays) on the moving car. The magnetic field from the arrays induces repelling currents in a close-packed array of shorted circuits in the track. Above a low transition speed (a few kilometers per hour), levitation forces approach a constant value, while drag forces decrease inversely with speed, with L/D reaching 200:1 or more at operating speeds. The high magnetic efficiency of the Halbach arrays, plus the use of close-packed track circuits, results in levitating forces approaching 40 metric tonnes per square meter (using NdFeB permanent magnet arrays, whose weight in typical cases is a few percent of the levitated weight). The system is passively stable: only motion is required for levitation. Failure of the drive system only results in the train slowing down and settling onto auxiliary wheels at a low speed. A detailed theoretical analysis of the Inductrack was made, on the basis of which a small-scale model was constructed and operated. The Laboratory is building a new small-scale model system (under NASA sponsorship) to demonstrate the acceleration rates and speeds (10-g and Mach 0.4 in the model) needed to magnetically launch rockets.

Although the maglev operating technology could produce smooth train rides at speeds up to 500 km per hour, no full scale operating maglev system has been built. The problems encountered, such as being much more expensive than conventional railways and as yet, not fail-safe, have limited the maglev application. A new design which uses no superconducting magnets or powered electromagnets is being developed. Named Inductrack, it uses permanent room-temperature magnets which are similar to bar magnets. In this concept, the underside of each train car has an Halbach array of magnetic bars which produce a very strong magnetic field. The track has closely packed coils of insulated wire and each coil is a closed circuit. The Inductrack produces levitating forces by inducing electric currents in the track. This article explores the theory of Inductrack and presents other possible uses for this new concept.

A principle of hybrid magnetic levitation system using permanent magnets (PMs) and high-temperature superconductors (HTSCs) for a linear-motor-type carrier system in a high-quality clean room and a magnetic bearing for the flywheel energy storage system are discussed. A substantial levitation force was generated by the repulsive force between like poles of coupled magnets. However, the repulsion system with magnets is essentially unstable without control. Thus, HTSCs are applied for control elements of the PM-HTSC hybrid magnetic levitation system. In this system, the levitation force becomes stronger than in the system without PM, and we can expect sandwich-type magnetic bearing capable of sustaining greater force. © 1998 Scripta Technica, Electr Eng Jpn, 124(4): 56–63, 1998

A fast computer code that generates currents and forces for multiple magnetic levitation (MAGLEV) vehicle coils over a discrete guideway of arbitrary geometry has been developed, tested, and verified. A study of coil dimensions for overlapping loops, ladders, and discrete loops has been conducted to determine the optimal guideway design. A parameter known as "figure of merit" has been defined to assist in evaluating the level of "merit" for a particular track configuration. From this, it has been discovered that, for most cases, ladder tracks are a better configuration over both overlapping and discrete loops. On closer inspection, it was also discovered that an aspect ratio of unity for the dimensions of a ladder track yields the best overall results.

A principle of hybrid magnetic levitation system using permanent magnets (PM) and high temperature superconductors (HTSC) for a linear-motor-type carrier system in a high quality clean room and a magnetic bearing using for the flywheel energy storage system are discussed. The substantial levitation force was generated by the repulsive force between the same poles of coupled magnets. However the repulsion system with magnets is essentially unstable without any control. Then HTSC is applied for control elements of the PM-HTSC hybrid magnetic levitation system. In this system, the levitation force becomes stronger than the system without PM. And we can expect the sandwich type magnetic bearing greater force.

This paper deals with the design of levitation electromagnet for super high speed magnetic levitation (Maglev) vehicle. Electromagnetic characteristics of levitation magnet are analyzed by finite element analysis. Levitation force ripples and cogging force are reduced by adopting core separation. 4-pole cutoff model has been manufactured to verify the design. A static force experiment is carried out with test model.

This paper describes the levitation and guidance control of a passive magnetic levitation tray system. In this system, a moving tray is completely contactless and has no electric equipments. Lifting, guiding and propelling forces are generated by external electromagnets. Especially, we focused on the levitation and guidance control in this paper. We designed the controllers and evaluated their performances through experiments.

Two methods for superconducting magnetic levitation are investigated to enhance levitation characteristics such as levitation force and horizontal stability. In one of the investigated methods, not only a repulsive force between a permanent magnet and a superconductor but also the force between two permanent magnets is utilized to achieve strong levitation force and horizontal stability. In an other method, a high Tc superconductor was preliminarily magnetized by a permanent magnet via a field-cooling process. Levitation forces and horizontal stability in the proposed system were numerically evaluated using a computer program based on the critical state model.

This paper describes the influence of the nonlinear characteristics of a magnet, which is expected to have a large influence on levitation performance of a maglev vehicle with mechanical air gap control. The effect of nonlinear characteristics of magnets on levitation performance, which is expressed by the guide wheel load of the vehicle, is initially analyzed from a static point of view. Numerical calculation and experiments using test vehicle are carried out to show nonlinear effect of the magnet on the levitation performance. The dynamic levitation performances are analyzed by a simulation study with 3 DOF and 17 DOF vehicle models. The simulation results show that the unstable rolling motion of the undercarriage is caused by nonlinear characteristics of magnets if a low control lever ratio is set. It is also shown that the deterioration of levitation performance caused by nonlinear characteristics of magnets is suppressed by a large control lever ratio.

This paper describes the levitation mechanism of a maglev planar transportation vehicle. Levitation force is generated using magnetic wheels and nonmagnetic conductor. The combination of the linear induction motor mechanism enables the vehicle to do planar motion. The effects of the major design parameters are estimated through the analysis and experiments. Parametric design to get required performance of the levitation mechanism is achieved using those design parameters.

A new type of magnetic levitation mechanism has been proposed. The feature of this mechanism is using wireless power supply system and Lorentz forces for levitation. The stability of levitation is performed by passive control by magnetic flux configuration between permanent magnets and active control of electromagnets. In this paper, the concept of levitation mechanism is introduced, FEM analyses for levitation force and wireless power supply performance is examined. In concept two types of levitation systems which are different on the point of active control directions are introduced. In FEM analyses, the required current for levitation and the directions of generating forces are calculated. In the study of wireless power supply system, the required voltage for the levitation is expected. Finally the feasibility of the proposed levitation system will be verified.

The dynamic response of a magnetic levitation (maglev) transportation system has important consequences for guideway design and system costs. The objective of this research is to develop a framework to analyze the dynamic interaction between a flexible guideway structure and a maglev vehicle named Electric Cargo Conveyor (ECCO). Different from other maglev vehicles, which use either electromagnetic or electrodynamic suspension technologies, the ECCO is the only system utilizing the Inductrack levitation technology, where the permanent magnets are arranged as so-called Halbach arrays to create a levitating force. The theoretical dynamic model of the ECCO system is derived in this paper. The guideway structure is modeled as a simply supported beam based on Bernoulli-Euler beam theory. The vehicle is modeled as a two-degree-of-freedom mass-damper-spring system. They are coupled with each other through nonlinear magnetic forces. To investigate the dynamic interaction between the vehicle and guideway, a finite element model of the ECCO system is created in COMSOL Multiphysics using its equation-based modeling interface. Numerical simulations are conducted to examine the effects of different factors such as the cargo weight and the vehicle speed.Copyright © 2012 by ASME

A study that compares between decentralized and centralized controllers for electromagnetic suspension (EMS) Maglev systems that use combined magnets with an inverted U-rail for levitation and lateral control is presented. A simple 2-DOF (degrees of freedom) Maglev system model (rigid and flexible body cases) that comprises heave and lateral modes is used. The study is based on two aspects. First, by sketching the multi-input multi-output (MIMO) root loci with every controller individually for system rigid and flexible body cases. Second, a gradient-like search algorithm based on an optimal criterion for decentralized and centralized controllers' gains tuning is used. The work is generalized on a real EMS Maglev system, and the simulation results for these Maglev systems shows that the centralized control is more capable of lateral displacements suppression that may result from disturbing lateral forces than the decentralized one.