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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.

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 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 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.

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 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.

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.

The levitation force and thrust in a current-controlled single-sided linear induction motor which propels electrodynamically-levitated vehicles are discussed. It has been shown theoretically that the single-sided linear induction motor (SLIM) can operate satisfactorily over suitably large clearance gap compared with the effective height of electrodynamic suspension. The levitation force in SLIM can be used practically as an alternative levitation force in the low-speed region by supplying a primary current several times the rated current within the very short acceleration times. In high-speed Maglev vehicle system with electrodynamic suspension and SLIM propulsion, the aluminum plate for levitation can be saved for the distance to accelerate the vehicle to speeds sufficient for electrodynamic levitation by the cryogenic magnets.

Recently, magnetic levitation device have been attractive. In magnetic levitation system we think PM-type magnetic levitation system is suitable for convyer system in facilities. From this viewpoint, we studied the PM-type magnetic levitation system, and we successfully levitated such devices. But then its structure was very unstable in control, so it had to control in a small compass and seosors and control system had to be precise. To control it easy, we thought the method to reduce lateral force by new arrangement of PMs. It's the way which arranges vehicle side PMs in parallel to the track side PM and we analyzed the repulsive force based on surface current on PMs. By this method, we have reduced lateral force by arrangement of PMs. To verify the calculated characteristics, we made the equipment to measure the repulsive force and we obtained measured value. The measured value agreed well with calculated value. We verify the method of analysis and the possibility to reduce lateral force by the arrangement of magnets.

Analyses have been made of the design parameters which affect the magnetic lift and drag forces on the magnetically suspended very high speed train models of practical interest. In the suspension systems investigated here, the superconducting magnets are installed in the train and the roadbed is equipped with normal-conducting coils. As a result of this investigation, an improved suspension system is proposed, which consists of "ladder-type conductor" in the roadbed. This new system is investigated theoretically.

It has been generally believed that the magnetic levitation of trains of the induction-repulsion type needs large ampere turn on the train magnets, and only superconductive magnets make the magnetic levitation feasible. However, the magnetic levitation becomes feasible also with the normal conductive electromagnet if the iron magnetic path is properly provided. An experimental example has been investigated. For details, see Digests of the 1972 Intermag Conference (available from IEEE Headquarters).