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Revolving magnet wheels with permanent magnets
Abstract
A new type of actuator with both magnetic levitation and linear drive is proposed. The actuator, called magnet wheel, has a rotating magnetic field obtained by revolving permanent magnets with high coercivity mechanically. The induction repulsive‐type magnetic lift force with self‐stabilization can be obtained by linking the rotating flux to a conducting plate. The induced simultaneous drag torque, which causes power loss, is used to obtain thrust in two proposed ways. These are called “tilt type” and “partial overlap type,” respectively. In the tilt type, the magnet wheel is tilted against the surface of a conducting plate. In the partial overlap type, the magnet wheel operates near the edge of a conducting plate.
In this paper, the fundamentals of the structure of proposed magnet wheels are described. The basic characteristics at parallel to the conductor are shown by using a numerical three‐dimensional electromagnetic analysis and measured results. The generation of both lift force and thrust in tilt type and partial overlap type magnet wheel are proved by experiments, respectively.
... Compared with others, the pretty disparity of the permanent magnet electrodynamic wheel (PM EDW) is known as the levitation-propulsion integration. The PM EDW has been proposed for over decades [9], the concept regains popularity in the realm of Maglev car application. A novel Maglev car and the various operation modes were proposed and introduced by our group [10], [11], [12]. ...
... Characteristics of the radial PM EDW have been studied, and conclusions indicate that the PM EDW system resembles a linear induction motor (LIM) without back-iron [26], [27], [28], [29] for a traveling magnetic field is generated and only a passive guideway is required to create the propulsion force. In other words, the EDW can be thought to be a new type of actuator with both magnetic levitation and linear drive [9], [30]. The electromagnetic forces are closely related with the relative slip speed v s resembling that of a LIM. ...
... The magnetic field generated by the EDW is modeled using an equivalent fictitious magnetic charge cylindrical [32], [33]. The z-axis component of B 1 can be derived as listed in (9). ...
The levitation-propulsion integration ability of radial permanent magnet electrodynamic wheel (PM EDW) renders its competitive edge over other magnetic levitation systems. A low-cost and effective second induction method is proposed to target the synchronous improvement of the saturation speed, levitation and propulsion forces. Its effectiveness is determined from the small-scale EDW to the full-scale EDW via theoretical model, simulation analysis and experiments test. First, according to magnetic charge theory, an updated EDW is proposed and developed. Simulated and tested results of the small-scale EDW demonstrate that the levitation force, propulsion force and saturation speed are increased by 14%, 7% and 30%. This improvement benefits the increased induction current and the mitigated skin effect. Afterwards, further analysis of the full-scale EDW with rings of various conductivity and thickness is conducted. The levitation force, propulsion force and saturation speed are enhanced by more than 50%, 10% and 200% synchronously. Based on analysis of power loss under the same levitation and propulsion forces, the updated EDW is more efficient than the original EDW. Ultimately, a proof-of-principle prototype with the updated EDW and 4-m long guideway are developed. The multi-loop PID control strategy along with dynamic mode implementation methodology are introduced. The scaled prototype is levitated over guideway at 12 mm and the levitation-propulsion ability is implemented with the maximum acceleration of 1.25 m/s
2
. This proof-of-principle prototype with updated EDW and control strategy paves the way to engineering applications of Maglev car.
... (sheet), 평판의 이송에 효과적으로 이용될 수 있다 [1][2][3] . 이러한 응 용에 있어 관건은 자기차륜의 회전에 의해 생성되는 자기력의 제어 성(controllability)에 있다. ...
... 후자의 경우 평판과의 대항 면적이 작아 힘밀도 측 면에서는 상당히 불리하며 평판 이송보다는 자기부상 열차와 같은 대용량 시스템에의 응용이 모색되었다 [5] . 축형 차륜을 이송력으로 이용하기 위해 회전 토크는 추력으로 전환되어야 하는데 이를 위해 차륜을 평판 모서리와 일정 부분 중첩시키거나 차륜의 축을 기울여 부상력을 분할해서 사용하는 방법이 제안되었다 [1] . 그러나 발생한 추력이 부상력과 강하게 연성되어있고 이러한 힘들을 독립적으로 제어할 수 있는 방법에 대해서는 연구된 사례가 없다 [4] . ...
Two-axial electrodynamic forces generated on a conductive plate by a partially shielded magnet wheel are strongly coupled through the rotational speed of the wheel. To control the spatial position of the plate using magnet wheels, the forces should be handled independently. Thus, three methods are proposed in this paper. First, considering that a relative ratio between two forces is independent of the length of the air-gap from the top of the wheel, it is possible to indirectly control the in-plane position of the plate using only the normal forces. In doing so, the control inputs for in-plane motion are converted into the target positions for out-of-plane motion. Second, the tangential direction of the open area of the shield plate and the rotational speed of the wheel become the new control variables. Third, the absolute magnitude of the open area is varied, instead of rotating the open area. The forces are determined simply by using a linear controller, and the relative ratio between the forces creates a unique wheel speed. The above methods were verified experimentally.
... Thus, this paper defines d and d s as the ratio of the distance between the centers of the DEDWs to the outer diameter of the EDWs, as shown in Eqs. (10) and (11). In the content related to EDWs' size, d and d s will be used as the index for wheelbase design because of the above reason, ...
With the advantage of “suspension-drive” integration, the Maglev car has broad application prospects in fields, such as Maglev highways. Currently, a laboratory-scale Maglev car prototype has been built by one of the groups of Southwest Jiaotong University equipped with four permanent magnet electrodynamic wheels. A full-scale Maglev car is planned for design. The distance between the front and rear electrodynamic wheels (EDWs) of a Maglev car will directly affect the safety of the entire car system operation; therefore, it is necessary to explore the wheelbase design. This paper first analyzes the relationship between the electromagnetic force of double EDWs (DEDWs) and the wheelbase under the size of a scaled prototype through 3D simulation and verifies the effectiveness of the simulation model through experiments. Furthermore, the electromagnetic force characteristics of full-scale DEDWs were explored through finite element simulation methods. Finally, we provide the wheelbase design standards for the Maglev car of any size. The findings indicate that the electromagnetic force of DEDWs first rapidly decreases and then stabilizes with increasing wheelbase. The ratio of the inner and outer radius of the DEDWs, and the material and thickness of the conductor plate do not affect the critical value of the wheelbase, while the rotation speed and air gap of DEDWs are the parameters affecting the design of the wheelbase. This article provides a new idea for the wheelbase design of the Maglev car, which is expected to provide some reference for the structural design and parameter optimization of multi-EDW devices.
... N. Fujii et al. [32,33] proposed a vertical permanent magnet wheel structure which was placed above the edge of the conductive track. It can not only generate levitation force, but also generate propulsion force and lateral force. ...
Based on the principle of permanent magnet electrodynamic suspension (PMEDS), a new concept maglev car was designed by using rotary magnetic wheels and a conductor plate. It has the advantages of being high-speed, low-noise, environmentally friendly, safe and efficient. The PMEDS car is designed to use a permanent magnet electrodynamic wheel (EDW) to achieve the integration of levitation force and driving force. The levitation force is generated by the repulsive force of the eddy current magnetic field, and the driving force is generated by the reaction force of magnetic resistance. A simplified electromagnetic force model of the EDW and a dynamics model of the PMEDS car were established to study the operating mode. It shows that the PMEDS car can achieve suspension when the rotational speed of the EDWs reaches a certain threshold and the critical speed of the EDWs is 600 rpm. With the cooperation of four permanent magnet EDWs, the PMEDS car can achieve stable suspension and the maximum suspension height can reach 7.3 mm. The working rotational speed of EDWs is 3500 rpm. At the same time, the movement status of the PMEDS car can be controlled by adjusting the rotational speed of rear EDWs. The functions of propulsion, acceleration, deceleration, and braking are realized and the feasibility of the PMEDS car system is verified.
... Although low or high-temperature superconductors may be used a significantly lower cost solution is achieved by using rare-earth Nd-Fe-B magnets [81]. Fujii and Ogawa first considered rotating axially placed rare-earth magnets [80,[84][85][86][87]. Two proposed methods for creating thrust and suspension force simultaneously using a tilt and an overlap type magnet wheel is shown in Fig. 11 and Fig. 12. ...
... The magnitude of F B for any magnet configuration can be numerically calculated using the techniques described by Meeker [31]. If a WMB is used in a single-sided RLFF, such as those used by Priede et al [32] or Bucenieks [18,22], care should be given to account for electromagnetic lift forces generated by the RLFF [33][34][35]. These lift forces (F L ) could be problematic during flowmeter startup or flow transients when the relative velocity between the fluid and the magnets is the greatest. ...
A 'weighted magnetic bearing' has been developed to improve the performance of rotating Lorentz-force flowmeters (RLFFs). Experiments have shown that the new bearing reduces frictional losses within a double-sided, disc-style RLFF to negligible levels. Operating such an RLFF under 'frictionless' conditions provides two major benefits. First, the steady-state velocity of the RLFF magnets matches the average velocity of the flowing liquid at low flow rates. This enables an RLFF to make accurate volumetric flow measurements without any calibration or prior knowledge of the fluid properties. Second, due to minimized frictional losses, an RLFF is able to measure low flow rates that cannot be detected when conventional, high-friction bearings are used. This paper provides a brief background on RLFFs, gives a detailed description of weighted magnetic bearings, and compares experimental RLFF data to measurements taken with a commercially available flowmeter. © 2018 Not subject to
... (radial type)으로 구분된다[1][2][3]표 1. 전도성 평판의 반송 시험을 위한 동전기 휠의 제원.정 광 석 232 ...
Shielding the air-gap magnetic field of the electrodynamic wheel below a conductive plate and opening the shielding plate partially, a thrust force and a normal force generate on the conductive plate at the open area. But, as only the variable controlling both forces is a rotating speed of the electrodynamic wheel, it is very difficult to control the forces independently by the speed. So, we discuss a novel method controlling the forces effectively through manipulating a size of the open area. The independent control is made possible by virtue of the feature that the relative ratio between both forces is irrelevant to an air-gap length and determined uniquely for a specific rotating speed of the wheel. Therefore, the rotating speed and the size of open area become new control variables. The feasibility of the method is verified experimentally. Specially, the controllable magnetic forces are used in a noncontact conveyance of the conductive plate.
... A number of researchers have been considering using rare-earth magnets for maglev applications. Most recently, Fujii showed that the rotation of axially placed rare-earth permanent magnets over the edge of a conductive track could create lift and propulsion force simultaneously, in addition, guidance forces were created when the track had an incline [5, 6]. Unfortunately the performance when operating with translational motion and thrust efficiency results have not be published, also no scaling discussion has been provided for the axial magnet rotation maglev system. ...
The mechanical rotation of a radially positioned permanent magnet Halbach array above a conducting, non-magnetic, track creates a traveling time-varying magnetic field that can inductively create levitation and propulsion forces simultaneously. This 'Electrodynamic Wheel' (EDW), could be used to create a relatively cheap form of maglev transportation since the track would not need to be electrified and both the levitation and propulsion forces would be created by one mechanism. The various parameters that influence the performance of such a maglev system have been studied by using a 2D steady-state Finite Element Method. The effect of the pole number, magnet thickness, radius, track thickness, and track conductivity on the EDW performance were considered. Design guidelines and methods to further improve the EDW performance are suggested.
The permanent magnet electrodynamic wheel system is a competitive alternative for achieving linear propulsion due to its integrated propulsion-guidance capability. In this paper, an integrated propulsion-guidance system comprising a conductive plate and a permanent magnet electrodynamic wheel (PMEDW) is developed and investigated for implementation in a high temperature superconducting (HTS) maglev prototype. Firstly, an analytical model combined with a simulation model is established and verified through experimental results. Furthermore, the impact of conductive plate thickness and working air gap on propulsion performance is analyzed. The correlation between the PMEDW system and permanent magnet guideway (PMG) is also explored. Moreover, the characteristics of the completed propulsion-guidance HTS system are studied, including propulsion ability and guidance performance. Finally, a small-scale experimental prototype with an auxiliary PMEDW is developed, and dynamic experiments are carried out. The outcomes demonstrate that the proposed propulsion system can sufficiently drive the HTS maglev module and enhance the guidance capability. The findings can serve as a reference for subsequent applications of the HTS maglev train traction system.
A magnetic-levitation system using a rotating permanent magnet has been developed. Pole pitch of the magnetic wheels and thickness of the metal plates required for levitation were investigated by experiments and computational calculation. To determine the optimum conditions, the levitation force, generated using motors with different torque and rotation speeds, was measured. These measurements clarified differences in the generated levitation force due to the different rotational speed and torque. Parameters, such as skin depth, magnetic density, eddy-current distribution density, the ratio of drag force to levitation force, and levitation force per driving power were numerically calculated from the magnetic field created by the rotating permanent magnet and effective frequency. Magnetic wheels should be designed to be large and the pole pitch of magnets was to be wide, and the levitation force per driving power will be improved in proportion to the root function of the pole pitch between magnets.
The contradiction between supply and demand of road transportation is prominent and the traffic load is increasing day by day, which makes it face a new challenge. Maglev car is the application of maglev technology to the automotive field, so as to realize the non-contact operation of the vehicle and the road, reduce the running resistance, improve speed and road operating efficiency. This paper studies a special permanent magnet electrodynamic suspension (PMEDS) structure that can convert magnetic resistance into propulsion force which is called as electrodynamic wheel (EDW). The primary electromagnetic characteristic of the PMEDS system employing an annular Halbach structure was analyzed by simulation and experiments. Firstly, the physical model of EDW was established to introduce the working principle and structural characteristics in detail, and a 2D finite element simulation model by ANSYS Maxwell was established. Subsequently, the structural parameters of the permanent magnet wheel and the induction plate were optimized. Then, a PMEDS test platform was designed based on the simulation results. Compared with the experimental results under dynamic conditions, the finite element simulation results are in good agreement with the experimental results. The results show that the EDW can achieve stable levitation force and propulsion force at the same time, which indicates a possible technical approach for maglev car.
When an array of rare-earth magnets, embedded in a rotor, is subjected to mechanical rotation over a conductive, paramagnetic guide-plate, where the axis of the rotor is perpendicular to the guideway, it induces eddy currents that create a counter magnetic field resulting in levitation and drag forces. Since the net drag force in the guide-plate is zero, hence, rotors only generate levitation forces that stabilize the system without creating any directional motion. This paper is an attempt to investigate the effects of varying parameters (rotational speed of rotors, number of magnetic poles and material & dimensions of guide-plate) on a “quadcopter” working on electromagnetic levitation achieved by spinning electrodynamic rotors. Additional investigation on the effect of an increase in temperature of the guide plate on the lift of the quadcopter was also recorded.
Putting a conductive rod between rotating axial electrodynamic wheels composed of repetitive permanent magnets, three-axial magnetic forces generate on the conductive rod. It is possible to levitate and transfer the rod on space with the forces. However, the forces vary in direction and magnitude for a position of the rod between the electrodynamic wheels. Thus, the position influences the stability of the rod also. To guarantee the stability of a levitated object, the force acting on the object should have negative stiffness like a spring. So, we analyze the stable operating range of the conductive rod levitated by the axial wheels with the commercial finite element tool in this paper. Specially, as the pole number and the radial width of permanent magnets has much influence on the generated force and thereby the stable region, their sensitivities are analyzed also. The analytic result is compared with experimental result.
When a conductive rod is put within rotating axial magnet wheels arranged parallel, three-axial magnetic forces generate on the rod. In some region, the forces has a property of negative stiffness, thus they can be applied to noncontact conveyance of the rod without a control load. Apart from the passive driving, the magnet wheel should be controlled for the rod to be stayed at the still state or be moved in a specified velocity. But, because a control input is just the rotating speed of the magnet wheel, the number of input is less than that of variables to be controlled. It means that levitation force and thrust force increase at the same time for increasing wheel speed, resulting from a strong couple between two forces. Thus, in this paper, a novel method, in which the longitudinal motion of the rod is controlled indirectly by the normal motion of the rod with respect to the wheel center, is introduced to manipulate the rod without mechanical contact on space.
An axial magnet wheel, in which permanent magnets are arranged circumferentially and polarized periodically, is proposed as a driving method to transfer a conductive rod without mechanical contact in space. The magnet wheel, whose axial plane is laid parallel to the rod, is rotated to generate three axial magnetic forces on the rod. But, the all forces are strongly coupled to each other through the rotational speed of the wheel. Furthermore, the number of degrees of freedom to be controlled in the transfer system, in which the rod is supported by two pairs of magnet wheels actuated by two wheel motors, is more than the number of input variables. To solve the above problem, a novel method in which the transfer control of the rod is converted to a tilt control of the rod is proposed and verified experimentally. And, the force characteristic of the magnet wheel is analyzed for variations of the main geometric parameters to obtain the desired design specifications.
A spiral electrodynamic wheel is proposed as an actuator for the contactless conveyance of a conductive rod. When rotating the wheel around the rod, a radial force, a tangential force, and an axial force are generated on the rod and cause a screw motion of the rod. The rotation of the rod is the inevitable result due to traction torque of the wheel and the unintended motion to be excluded. However, the rotating speed of the rod should be measured without mechanical contact to be cancelled out through the controller, so the electrodynamic wheel is used as a sensor measuring the rotating speed of the rod indirectly as well as an actuator. In this paper, we model the magnetic forces by the proposed wheel theoretically and compare the derived model with simulation result by Maxwell, and analyze influences on the magnetic forces by key parameters constituting the wheel. The feasibility of the conveyance system is verified experimentally.
The partial shielding of the magnetic field generated by a magnet wheel that rotates under a conductive plate generates two linearized axial electrodynamic forces similar to those generated by a linear induction motor on the plate over the non-shielded open area. The forces are strongly coupled by the rotating speed of the magnet wheel, which is the only control variable. Therefore, to position the plate in space as desired, another control variable besides the wheel speed is needed. So, in this paper, the absolute size of the open area is proposed as a new variable. Around the nominal rotating speed, the normal force is much more sensitive than the thrust force to the speed of the wheel. Therefore, the speed roughly corresponds to the normal force, and the size of the open area corresponds to the thrust force. Of course, a variation of the normal force due to a change in size of the open area should be compensated by controlling the wheel speed. As another case for the positioning of a conductive plate, the in-plane positions of the plate can be controlled indirectly by out-of-plane control with respect to the target air–gaps obtained by the in-plane controller. Although the only controlled variable is the air–gap lengths, in-plane control forces are reflected in determining the air–gap lengths. The above methods are verified experimentally.
As a method obtaining linear thrust force for the magnet wheel producing a strong traction torque, the concept of magnetic shield is suggested and compared with the existing approaches. Specially, as the magnet wheel, in which the permanent magnets rotate mechanically instead of ac driving to make traveling field, is physically similar with the rotary induction motor, there is a periodical force ripple in tangential direction as well as normal direction. But, the force ripple can be suppressed from a shape change of the shield plate. Namely, the change brings out a change of entry and exit effect of the circumferential field for the magnet wheel. The feasibility of the shield concept is verified from simulation and experiment.
A magnet wheel is chosen as the driving method to transfer a conductive plate without mechanical contact in space, due to its high force density. When permanent magnets (hereafter PMs) constituting the magnet wheel rotate below the conductive plate, not only a repulsive type of normal force but also a traction torque is generated on the plate. To utilize the torque as a thrust force, the magnetic fields from PMs are covered partially using a magnetic shield plate. So, in-plane positions of the conductive plate are controlled by turning the shield plate opened partially. In this paper, the operating principle of the noncontact conveyance system using a magnet wheel is discussed, including experimental verification. Specially, the resulting force from the suggested magnet wheel is AC force with oscillation, but it can be minimized through varying entry or exit shape of the open area of the magnetic shield plate.
We have proposed the “magnet wheel” which is a magnetic wheel with the functions of induction repulsive-type magnetic levitation and linear thrust using mechanically revolving permanent magnets. We designed and produced a magnet wheel installed winding for own drive. In the unit, a synchronous motor is constructed by adding only the armature winding because the strong magnets of the magnet wheel are used in common for the field pole of synchronous motor. For the design, the relational expression between the lift force and the driving power is shown. Compared with arrangements using a separate motor, a very compact and light magnet wheel can be constructed. The produced magnet wheel with outside diameter of 190 mm has the payload of about 10 kg at the mechanical clearance of 15 mm
The authors earlier proposed a revolving permanent-magnet type wheel called the “magnet wheel,” which has the functions of both induction repulsive magnetic levitation and thrust. In this paper, the relationship between magnetic poles and lift force or thrust characteristics is examined to investigate the performance. Five types of magnet wheels are discussed in an experimental study and four more types are used in a theoretical study with three-dimensional numerical analysis. The following parameters are considered: magnetomotive force (mmf) of a permanent magnet; thickness of the magnet in the magnetizing direction; total volume of magnets; fundamental factor; distortion factor of the space mmf distribution of poles; pole pitch; diameter of magnet wheel; mechanical clearance; and thickness and resistivity of conducting plate. The results show the following: 1. The lift force per unit of magnet volume is approximately proportional to the fundamental factor of the space mmf distribution of the poles. A low degree space harmonic mmf is effective in increasing lift force. 2. The driving power per unit of lift force is almost entirely independent of the configuration of the primary member, including pole arrangement and position relative to the secondary conducting plate, respectively, and depends only on the resistance of the conducting plate. 3. In both the “partial-overlap type” and “tilt type” magnet wheels, many poles with sufficiently large pole pitch are useful. In the tilt type the use of a small tilt angle is desirable. © 1999 Scripta Technica, Electr Eng Jpn, 128(4): 111–120, 1999
Lift force, thrust and lateral force characteristics of
“partial overlap type magnet wheel” are presented, where
“magnet wheel” is a proposed electromagnetic device for an
induction repulsive type Maglev vehicle constructed with revolving
permanent magnets and conducting plate, and “partial overlap
type” is one type of magnet wheel. Smaller resistivity of the
conducting plate induces larger lift force and lateral force except
thrust. The 2-pole arrangement has maximum thrust at larger overlap than
4-pole. The wall of the conducting plate gives larger lateral force
without adverse influence on lift force and thrust
The characteristics of magnet wheels for magnetic levitation and
linear drive applications are investigated by using a three-dimensional
computer simulation. Magnet wheels levitate by revolving permanent
magnets over a conducting plate, in which eddy currents are induced.
Thrust is also produced by making the torque unbalanced. This paper
deals with “partial overlap type” magnet wheels, producing a
lift force and thrust. Magnetic flux density and eddy currents are
examined for both 3-pole and 2-pole structures
For a simple Maglev mover, the magnetic levitated, propelled and
guided mover using the “magnet wheels” is discussed. The
“magnet wheel” generates both the induction repulsive type
magnetic lift force and the thrust by rotating permanent magnets
mechanically over the conducting plate. The “partial overlap type
magnet wheel” is used in the paper, in which the thrust is
produced from the drag torque by setting the rotator near the edge of
the conducting plate. The Maglev device using the four magnet wheels can
levitate stably without vibration, pitching and rolling, and the damping
always exists for any condition at standstill. The configuration with
inclination magnet wheels at both sides makes the Maglev mover with
guidance
We present a two-dimensional complex steady-state finite-element method for calculating the lift and thrust or breaking forces created when a magnetic rotor is translationally moved and rotated over a conducting sheet. The method replaces the magnetic rotor with an equivalent current sheet by equating the current sheet's and magnet rotor's magnetic vector potentials. We validate the steady-state method by comparing the forces with transient finite-element models. The utility of this steady-state model is that it enables a study of the effects of parameter changes for such a machine to be undertaken rapidly.
When a magnetic rotor is both rotated and translationally moved above a conductive, nonmagnetic, guideway eddy currents are induced that can simultaneously create lift, thrust, and lateral forces. In order to model these forces, a 3D finite-element model with a magnetic charge boundary has been created. The modeling of the rotational motion of magnets by using a fictitious complex magnetic charge boundary enables fast and accurate steady-state techniques to be used. The conductive regions have been modeled using the magnetic vector potential and nonconducting with the magnetic scalar potential. The steady-state model has been validated by comparing it with a Magsoft Flux 3D transient model (without translational velocity) and with experimental results. The 3D model is also compared with a previously presented 2D steady-state complex current sheet model.
The mechanical rotation of a radially positioned permanent-magnet Halbach array above a conducting, nonmagnetic track induces eddy currents in the track that can inductively create suspension and propulsion forces simultaneously. The parameters that affect the performance of this electrodynamic wheel are studied using a 2-D steady-state finite-element method. Tradeoffs between the lift and thrust force performance are investigated and methods to improve the thrust efficiency are proposed.
In commercializing the superconducting maglev system it is important to reduce the cost, especially that of ground coils installed all along the guideway. The ground coils designed for Yamanashi test track under construction are composed of both eight-shaped null-flux coils for EDS (Electro-Dynamic Suspension) and double-layered armature coils of LSM (Linear Synchronous Motor). The former reduces the magnetic drag of the running resistance, and the latter reduces the electromagnetic fluctuation in the superconducting coils. Besides, the eight-shaped coils can generate propulsion force by being connected to the power supply. This system can generate levitation force, guidance force and propulsion force by the same ground coils. Therefore this system is expected to save the cost of ground coils, number of which are decreased. In this paper we present the principle and analytical formula of the combined propulsion, levitation and guidance system (PLG system), including one for angles. In addition, using numerical examples, the characteristics of this system are expressed.
There is a levitation method which uses 8-shape levitation coils arranged on the vertical surface of the guideway. These coils can act as a guidance means as well as the levitation means. The characteristics of this system is examined using numerical examples and experimental data. The cables connecting right and left coils are not connected to a high voltage power source unlike the usual guidance system which is combined with propulsion. Thus the electric insulation of the cables is now not a problem. Numerical examples show that the levitation characteristics of the combined levitation and guidance system is almost the same as in the system without the guidance function, and that it atains reduced running resistance with necessary guidance stiffness obtained. Test run was done at Miyazaki Test Line equipped with coils of this type arranged about 120 m, and the results show stable running and balanced displacement which agrees with calculated value. © 1992, The Institute of Electrical Engineers of Japan. All rights reserved.
In commercializing the superconducting maglev system, it is important to reduce the cost, especially that of ground coils installed all along the guideway. The ground coils designed for Yamanashi test track under construction are composed of both octagonal-shaped null-flux coils for EDS (Electrodynamic Suspension) and double-layered armature coils of LSM (Linear Synchronous Motor). The former reduces the magnetic drag of the running resistance, and the latter reduces the electromagnetic fluctuation in the superconducting coils.
In addition, the octagonal-shaped coils can generate propulsion force by being connected to the power supply. This system can generate levitation force, guidance force and propulsion force by the same ground coils. Therefore this system is expected to reduce the cost of ground coils, the number of which is decreased.
This paper presents the principle and analytical formula of the combined propulsion, levitation and guidance system (PLG system), including one for angles. In addition, using numerical examples, the characteristics of this system are expressed.
In order to realize a completely contactless railway system, it is necessary to develop what is called the zero power control scheme that supports the total vehicular weight only by the permanent magnet. This research proposes three kinds of zero power control schemes for the four-point supported vehicle. An example of design procedure is presented that is effective for the control system whose parameters vary considerably, for instance, due to the variation of vehicular weight. Effectiveness of the proposed control schemes is demonstrated by simulation and experiments.
The HSST-03 is a new transport system and is due to be put on display for a test run at "the International Exposition, Tsukuba, Japan (EXPO' 85)" to be held in Japan in 1985. The design of the HSST-03 vehicle was conducted by the hands of Japan Air Lines and Sumitomo Electric Industries. The vehicle of the HSST-03 system is levitated by electromagnets and propelled by linear induction motors. It has a length of 13.8 m, a gross weight of 16 tons, and 47 seats for passengers. It is designed to serve as a means of passenger carriage in the Expo site. The vehicle assembly was completed in February, 1984, and the levitation test of the vehicle is under way. On the other hand, the track for the HSST-03, which has the length of about 350 m, is now under construction and will be completed by the end of June, 1984. The HSST-03 is characterized by the module system which has a LIM for propulsion and 4 magnets for levitation and guidance unitized in a box beam structure and will be applicable for high-speed operational vehicles in the future. We have already carried out preliminary experiments on the module system and other components, and obtained satisfactory results as expected earlier.
Two new types of magnet wheels are proposed for both magnetic levitation and linear drives. The permanent magnets (PMs) of the magnet wheel are rotated over the conducting plate to obtain an induction type of repulsive lift force which is useful for simple and self-stabilizing magnetic levitation. The drug torque induced simultaneously is put to good use to obtain thrust by two simple ways. In one type, called “tilt type”, the surface of rotating PM is tilted against the surface of the conducting plate. In another type, called “partial overlap type”, the rotator installed PM is set over near the edge of the conducting plate. The static characteristics of the magnet wheels are confirmed by experimental work and approximate analyses
The ROMAG system of magnetically guiding and propelling vehicles using ordinary-temperature linear electric motors which combine levitation, thrust, guidance, and dynamic active suspension to achieve a high ratio of payload to vehicle weight is described. The vehicle requires low-cost passive track and provides a high degree of passenger ride comfort. It is applicable for low-cost low-speed ″people-mover″ vehicles as well as high-speed interurban transport systems. The motors are single-sided linear motors with the wound part attached to the vehicle. The passive part is the ferromagnetic rail. The motors operate beneath the rail. Two different types of rails are possible. The rails can be simple steel bars with notches along the underside to provide high reluctance paths. The operation is that of a self-excited synchronous or reluctance motor with thrust proportioned to the relationship between the magnetizing-current phase vector and the rail notch position. For higher thrust (greater than 0. 2g accleration) the rail should contain short-circuiting conductors instead of open notches. The system then operates as a squirrel-cage induction motor with slip frequency proportioned to thrust. A servo system controls motor voltage so that magnetic lift force is constant as speed increases and as torque angle (or slip frequency in the case of an induction motor) increases.
Test facility and simple approximate analysis of static characteristics of magnet wheel
- N. Fujii
- K. Kawamura
- K. Naotsuka
- T. Nakao
Application of the Magnetic Levitation Train in the Federal Republic of Germany
- Raschbichler H. G.
Analysis for Static Characteristics of Magnet Wheels
- Fujii N.
- Naotsuka K.
- Ogawa K.
Analysis for static characteristics of magnet wheels
- Fujii N.
Test facility and simple approximate analysis of static characteristics of magnet wheel
- Fujii N.