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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.

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.

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».

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 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.

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.

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 (

The fundamental electromechanical interactions in a passive null-flux electrodynamic maglev system (EDS) are mediated by the voltages induced in the levitation coils by the sled magnets, and by the forces exerted on the sled as a result of the induced currents. This work presents a reliable and compact method to calculate these interactions by using analytical expressions of the magnetic field of a permanent magnet. The proposed approach provides a highly efficient and numerically stable approach to the computation of the flux induced in the levitation coils as well as the induced voltages and currents and lift, drag, and guidance forces acting on the sled's magnets. The analytical model is compared to a simplified algebraic model suitable for real-time control of EDS maglev suspension dynamics. Both models are compared with measurements and show good predictive quality.

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

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.

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.

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 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.

16th IEEE International Symposium on Electromagnetic Launch (EML) Technology -- MAY 15-19, 2012 -- Inst Strateg & Innovat Technologies (ISIT), Beijing, PEOPLES R CHINA WOS: 000319079100027 This paper deals with the design, construction, and especially the testing of a new magnetic levitation (maglev) train driven by an air-cored tubular linear induction motor. The proposed new design topology uses only one force-generating system (motor) to produce the three forces required in a maglev system: propulsion, levitation, and guidance, whereas classical maglev trains use separate motors or permanent magnets to produce each of these forces. Moreover, the system eliminates the need for control of the levitation and guidance forces. This paper presents a condensed design guideline, simply explains the implementation process of a laboratory-scale prototype, shows in detail the experimental test results-including the low-damping problem-and then addresses the advantages of the proposed system over existing maglev systems. IEEE, China Electrotechn Soc, IEEE Nucl & Plasma Sci Soc

It is presented in this paper an active magnetic levitation system used for the nanogram detection in biomedical domain. The design, simulation and levitation experiment are presented in detail. The device is composed of three parts: planar coil electro magnetic (EM) as lower stator, permanent magnetic (PM) as rotor and capacitance plate as lower stator. The levitation force versus displacement is analyzed by Ansys software and the air damping coefficient is also calculated. A dynamic model of levitation control is build to select control parameter and explain the experimental measurement. The stiffness versus frequency is analyzed. Experimental results of initial levitation, square wave response and sine wave sweep frequency response are presented and discussed. Preliminary measurements indicate that the response time for initial levitation is 0.2s, and the control current is 0.17A when the levitation height is 1mm. The quick-response performance is in agreement with the dynamic simulation by Matlab/Simulink. From sweep frequency experiment, it can be seen that when the levitation height is 1mm, the resonant frequency is 27.34Hz. The relationship between minimum detectable mass and frequency has been got. At last, the prospective MEMS design is proposed, which is applicable for the cancer cell weight detection.

All electro-dynamic levitation systems (EDS) have peak drag forces and peak and average power consumption to deal with in order to be viable in Maglev applications. Both factors affect the energy cost and the capital cost of the propulsion system. A significant improvement for EDS systems is a so-called null-current configuration. It consists of two Halbach arrays, one above the track and one below the track. The two arrays are oriented with respect to one another so that their horizontal field components add while their vertical field components oppose. In this way, the levitating field component is enhanced while the field component that excites the currents in the ladder-track between the two arrays is weakened. The basic idea is that the lower induced current and the higher levitating field component produce the necessary levitation force. At the same time the drag force is much lower, since it depends on the product of the induced current and the vertical field component.

the 1960s, transportation industry planners have sought an energy-efficient design for a train that can glide through air at speeds up to 500 kilometers per hour. This type of train, called a magnetically levitated (maglev) train, is thought to be a viable solution to meet the nation's growing need for intercity and urban transportation networks. However, despite some promising developments, unresolved concerns with the operation and safety of maglev trains has prevented the transition from demonstration model to commercial development. Inductrack, a maglev system originally conceived by Livermore physicist Richard Post, is designed to address these issues. Post's work on Inductrack began with funding from Livermore's Laboratory Directed Research and Development Program, and in 2003, the technology was licensed to General Atomics (GA) in San Diego for train and transit system applications. This year, members of the Livermore-GA team received an R&D 100 Award for Inductrack's development. Inductrack uses permanent magnets to produce the magnetic fields that levitate the train and provides economic and operational advantages over other maglev systems. It can be adapted to both high-speed and urban-speed environments. In the event of a power failure, the train slows gradually until it comes to rest on its auxiliary wheels.more » The maintenance requirements for Inductrack are also lower than they are for other systems, plus it has a short turning radius and is designed for quiet operation. Previous designs for maglev systems did not offer the energy efficiency or safety protections that are in the Inductrack design. Electromagnetic systems (EMS) use powered electromagnets to levitate the train. However, these systems are based on magnetic attraction rather than repulsion and thus are inherently unstable. In EMS trains, the levitation gap--the separation between the magnet pole faces and the iron rail--is only about 10 millimeters and, during operation, must be maintained to within {+-}1 millimeter. Position sensors and electronic feedback systems are required to control the magnetic current and to compensate for the inherent instability. This requirement, plus the onboard source of emergency power required to ensure operational safety during a sudden power loss, increases the complexity of EMS trains. In contrast, in electrodynamic systems (EDS), large superconducting magnet coils mounted on the sides of the train generate high-intensity magnetic field poles. Interaction of the current between the coils and the track levitates the train. At operating speeds (above a liftoff speed of about 100 kilometers per hour), the magnetic levitation force balances the weight of the car at a stable position. EDS trains do not require the feedback control systems that EMS trains use to stabilize levitation. However, the superconducting magnetic coils must be kept at temperatures of only 5 kelvins, so costly electrically powered cryogenic equipment is required. Also, passengers, especially those with pacemakers, must be shielded from the high magnetic fields generated by the superconductors.« less

The Inductrack magnetic levitation system, developed at the Lawrence Livermore National Laboratory, was studied for its possible use for launching rockets. Under NASA sponsorship, a small model system was constructed at the Laboratory to pursue key technical aspects of this proposed application. The Inductrack is a passive magnetic levitation system employing special arrays of high-field permanent magnets (Halbach arrays) on the levitating cradle, moving above a "track" consisting of a close-packed array of shorted coils with which are interleaved with special drive coils. Halbach arrays produce a strong spatially periodic magnetic field on the front surface of the arrays, while canceling the field on their back surface. Relative motion between the Halbach arrays and the track coils induces currents in those coils. These currents levitate the cradle by interacting with the horizontal component of the magnetic field. Pulsed currents in the drive coils, synchronized with the motion of the carrier, interact with the vertical component of the magnetic field to provide acceleration forces. Motional stability, including resistance to both vertical and lateral aerodynamic forces, is provided by having Halbach arrays that interact with both the upper and the lower sides of the track coils. At present, a 7.8 meter track composed of drive and levitation coils has been built and the electronic drive circuitry performs as designed. A 9 kg cradle that carries the Halbach array of permanent magnets has been built. A mechanical launcher is nearly complete which will provide an initial cradle velocity of 9 m/s into the electronic drive section. We have found that the drag forces from the levitation coils were higher than in our original design. However, measurements of drag force at velocities less than 1 m/s are exactly as predicted by theory. Provided here are recommended design changes to improve the track’s performance so that a final velocity of 40 m/s can be achieved with the existing track. This project was designed and built as part of a Phase II contract that started in Feb. 1999 and ended in Sep. 2000 at a cost of $600K. A detailed budget on how this funding was spent is also included here.

A small-scale model track of a new type of magnetic levitation system (dubbed the ``Inductrack`` system), and a passively magnetically levitated cart, has been designed, constructed and operated. The track consists of a close-packed array of rectangular levitation coils, 15 centimeters in width transversely and 20 meters in length. The array of coils is inductively loaded above and below its lower horizontal section with ferrite tiles. Paralleling the levitation coils on each side are aluminum-channel rails on which ride auxiliary wheels attached to the cart. The cart has, on its lower surface and on its sides, fore and aft, special arrays (``Halbach arrays``) of permanent magnet bars that produce a strong periodic magnetic field below the cart. This magnetic field, when the cart is in motion, induces repelling currents in the Inductrack coils, levitating it and centering it transversely. When mechanically launched (with a pulley- and-weight system) at speeds substantially above a ``transition speed`` of about 2 meters per second, the cart levitated and flew stably down the track, settling to rest on its wheels near the end of the track. In the last phase of the program an electromagnetic launching section consisting of another array of coils, connected to pulse-driver circuits, was added at the beginning of the track. Aided by an initial launch (from stretched ``bungee`` cords), this electromagnetic launching system was operated successfully, resulting again in levitation and subsequent stable flight of the cart.

In a superconducting magnetically levitated vehicle, the conventional wheel-rail system is substituted by a permanent magnet guideway (PMG) made with Nd-Fe-B magnets and carbon-steel interacting with bulk superconductors installed in the vehicle to promote the levitation. The main cost of this levitation system is the PMG. Two geometries that minimizes the total cost, for a given static levitation force (LFmin), are dynamically investigated and compared in this paper. Impulse response on time and frequency domains, stiffness, damping, and oscillation frequency are presented for different conditions. The experimental apparatus is also described.

This report describes theoretical and experimental investigations of a new approach to the problem of the magnetic levitation of a moving object. By contrast with previously studied levitation approaches, the Inductrack concept concept represents a simpler, potentially less expensive, and totally passive means of levitating a high-speed train. It may also be applicable to other areas where simpler magnetic levitation systems are needed, for example, high-speed test sleds for crash testing applications, or low-friction conveyer systems for industrial use.

Magnetic levitation type seismic isolation device composed of HTS bulks and permanent magnets can theoretically remove horizontal vibration completely. It is, however, not easy to generate the large levitation force by using only the levitation system composed of HTS bulk and permanent magnet (HTS-PM system). We focused on a hybrid levitation system composed of the HTS-PM system and the PM-PM system composed of only permanent magnets and investigated the suitable arranging method of the hybrid system for improving levitation force and obtaining stable levitation. In order to clarify the most suitable permanent magnet arrangement in the PM-PM system for the levitation force improvement, repulsive force between permanent magnets was measured in various kinds of the PM-PM system. The maximum repulsive force per unit area in the PM-PM system was at least three times larger than the levitation force per unit area in the HTS-PM system, so that the levitation force in the hybrid system was larger than that of the HTS-PM system. Stable levitation was also achieved in the hybrid system. This is because repulsive force in the PM-PM system against horizontal displacement was much smaller than restoring force in the HTS-PM system.

A large scale test facility for the high speed ground transportation system TRANSRAPID has been built in Emsland. In the near future this test facility will show the economic feasibility of such a system. An essential component of this system is the magnetic levitation and guidance system of the vehicle. The requirements on this suspension system are: good ride comfort, high reliability and low operating costs. The elements of the suspension system are controlled cross field electromagnets with massive iron cores and rails for guidance and controlled longitudinal field magnets with a laminated iron core and rail for levitation. The reason for lamination is the combination of three operating tasks in the levitation magnets. These are: levitation, propulsion, and inductive power transfer to the vehicle. These magnets generate the exciting field of the synchronous linear motor. Due to these tasks the theoretical model for a levitation magnet has to be expanded in order to be able to describe these effects in dynamic simulations. The mechanical and the electrical structure of the suspension system must have several redundancies in order to get a high overall safety.

The dynamic circuit theory for the analysis of the suspension characteristics of electrodynamic magnetic levitation schemes for realistic magnet and guideway configurations is reviewed. Electrodynamic forces and moments have been measured on a large-scale stationary superconducting magnet interacting with an aluminum strip mounted on the rim of a 7.6-m diameter rotating test wheel. Good agreement is found between analytical and experimental results over the speed range to 100 km/h for the electrodynamic forces of test configurations which provide a rigorous test for theory. The speed dependence of moments is reported and used to estimate the force distribution on the superconducting coil. The dynamic circuit theory is then used to determine the suspension characteristics of the levitation system for the proposed Canadian Maglev vehicle.

In a magnetically levitated railway system with superconducting vehicular magnetic coil, short-circuiting ground coil, and a loop-type track, the magnetic field produced by ground coils is not uniform and therefore the lift force fluctuates as the train moves and the magnetic flux of the superconducting magnet fluctuates with time. The sheet-type track consists of continuous conductive sheets of aluminum or copper. The levitation characteristics of the sheet-type track have been analyzed so far by directly solving Maxwell's equation or by replacing the sheet current by an image current. In these analyses, it has usually been assumed that the sheet is infinitely or semiinfinitely wide. Until now, the levitation characteristics of a sheet-type track with finite width have been analyzed little. An analysis is given in which a ground sheet with finite width is replaced by a number of conductors with square cross section arranged in the running direction. Self- and mutual inductances of the conductors are taken into account in calculating the levitation characteristics. Calculated levitation characteristics of the sheet-type track are compared with those of the loop-type track.

Thermographic techniques and rotating wheel experiments are used to examine magnetic forces and dynamics of levitated models. Induced track current and magnetic pressure distributions for moving superconducting levitation coils are infered from laboratory tests on coils with sinusoidal currents. Magnetic search coils and liquid crystal and infrared thermography are used to determine current patterns in thin aluminum plates. Theoretical justification for these methods is given and shows that sinusoidally induced patterns are similar to motion induced current distributions in the high speed thin track limit. The dynamics of a freely magnetically levitating model on a "V" groove rotating thin track shows that stable motions are possible for the "V" track. These tests also show that drag coupled yaw-roll-lateral instabilities are possible for certain model geometries.

The most important versions of the magnetic levitation technique are expounded in the following. The programme of the magnetic levitation development in the Federal Republic of Germany including the choice of the electromagnetic levitation technique and its development up to operational readiness are also described and accounted for. The present survey emphasizes the main advantages of the levitation system due to its specific characteristics, defines fields of application and shows concrete possibilities of use. Ways for an optimum development are briefly pictured.

A magnetic levitation system utilizing superconducting magnets is now being developed for a high speed ground vehicle. From a view point of ride quality, a damping force for the mechanical oscillation of a levitated vehicle is one of the most important problems in this levitation system. This paper presents the analysis of the magnetic damping force in a loop track magnetic levitaion system; the magnetic damping force is caused by track loops. It is theoretically pointed out that the magnetic damping force is "negative" except in an extremely low velocity range. The theory is applied to the estimation of the magnetic damping force in a train model of practical interest. The results of the estimation suggest that the negative magnetic damping force is considerably large in a median velocity range (100 ∼ 200 km/h). Passive damping has been also investigated; it is found that damper loops installed in the levitation cryostat is effective even in persistent mode operation. It is concluded that rather good ride quality will be obtained by use of the passive damping method.

An outline of the magnetic levitation project in Japan is given. Research has been concentrated on levitation system utilizing electromagnetic repulsive force between a normal metal track and on-board superconducting magnets. Development of levitation magnets together with other items basic for a levitation system is given.

According to the div B = 0 condition, permanent magnetic levitation along a track is possible with stable characteristics in only one dimension. Mostly, the vertical dimension will be preferred. Transverse stabilization is achieved by guide rollers and inductor combs of linear motors, respectively. If no high stability is required in the vertical dimension, e.g., because disturbing forces are small, the arrangement of magnets in the track can be designed in such a way that weak stability in the vertical direction results in weak instability in the direction transverse to the track. The lateral forces, which now have only weak destabilization effects, can be overcompensated by the centering forces of double comb linear induction motors. This weakly unstable characterristics of the levitation system entails major energy conservation as a result of lower ohmic losses in the reaction rails. A model exhibiting these weakly unstable characteristics has been investigated. Such levitation system can be made of two V-shaped grooves consisting of permanent magnetic dipole plates.

The characteristics of an auxiliary damper winding to improve the dynamic performance of the electrodynamic levitation system have been investigated. Passive and active damping are included in the study.

The basic properties of flat sheet and flat ladder levitation systems are compared and contrasted based on the assumption that identical quantities of material are used in their construction. It is shown that although ladder systems can produce slightly better lift-to-drag ratios, the overall performance of sheets is better, particularly where lateral destabilization must be minimized.

Simple "best case" calculations of power/lift and lift/ weight ratios for electromagnetic levitation systems using controlled permanent magnets are presented. The use of ferrite, alnico, and rare-earth permanent magnets is considered and it is shown that their use can substantially improve the potential performance of such systems. A major difficulty is that the very small control powers obtained may severely limit the stable dynamic operating range.

This paper describes the dynamics of the propulsion and levitation systems in the Maglev vehicle M-Bahn for low-speed urban transportation in which a controlled permanent-magnet-(PM) linear synchronous motor (LSM) is used and controlled for its propulsion and levitation. An elevated guideway is periodically supported by pillars and approximated by a sinusoidal track. To compensate for the static instability of the propulsion and levitation systems, the state feedback controllers for both systems are designed for the Maglev M-Bahn. The transient responses of the systems to the external step forces given in the longitudinal and/or vertical directions are simulated using the non-linear dynamic equations of the propulsion and heave motions, which were derived on a basis of the theory of the controlled-PM LSM presented previously by the authors.