Hybrid Maglev Research Articles

Backstepping fuzzy-neural-network control design for hybrid maglev transportation system.

This paper focuses on the design of a backstepping fuzzy-neural-network control (BFNNC) for the online levitated balancing and propulsive positioning of a hybrid magnetic levitation (maglev) transportation system. The dynamic model of the hybrid maglev transportation system including levitated hybrid electromagnets to reduce the suspension power loss and the friction force during linear movement and a propulsive linear induction motor based on the concepts of mechanical geometry and motion dynamics is first constructed. The ultimate goal is to design an online fuzzy neural network (FNN) control methodology to cope with the problem of the complicated control transformation and the chattering control effort in backstepping control (BSC) design, and to directly ensure the stability of the controlled system without the requirement of strict constraints, detailed system information, and auxiliary compensated controllers despite the existence of uncertainties. In the proposed BFNNC scheme, an FNN control is utilized to be the major control role by imitating the BSC strategy, and adaptation laws for network parameters are derived in the sense of projection algorithm and Lyapunov stability theorem to ensure the network convergence as well as stable control performance. The effectiveness of the proposed control strategy for the hybrid maglev transportation system is verified by experimental results, and the superiority of the BFNNC scheme is indicated in comparison with the BSC strategy and the backstepping particle-swarm-optimization control system in previous research.

The Effect of the Horizontal Distance between the Permanent Magnets on the Levitation Force in Hybrid Magnetic Levitation System

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

Study of the load reduction for hydro-generator bearing by hybrid magnetic levitation

To solve the problem of heat and friction existing in weight bearing of the hydraulic generator, a new type of magnetic levitation devices is proposed. The devices consist of electromagnetic and permanent magnetic levitation, which share together most of the hydraulic generator rotor weight to reduce axial load on thrust bearing. The permanent magnetic levitation is performed by new repulsive ring Halbach arrays. The new Halbach arrays are analyzed by using magnetic potential equations and superposition principle, and the magnetic flux density formulas are obtained. The formula results are verified by FEM. By further study of 3D model simulation analysis, it is confirmed that the new repulsive ring Halbach arrays can reach the design goal on actual working conditions.

The Effect of the Distance between the Permanent Magnets on the Levitation Force in Hybrid Magnetic Levitation System

t has been investigated that the interaction force in hybrid magnetic levitation systems with two GdBCO bulk superconductors and two permanent magnets system and a cubic permanent magnet (PM2) and a cubic permanent magnet (PM3) system in their coaxial configuration at liquid nitrogen temperature. The two single-domain GdBCO samples are of φ20mm and 10mm in thickness, the permanent magnet PM1 is of rectangular parallelepiped shape, the permanent magnets PM2 and PM3 are of cubic shape; the system placed on the middle of system and their coaxial configuration; It is found that the maximum levitation force decreases from 40.6N to 17.8N while the distance (Dpp) between the permanent magnets is increased from 0mm to 24mm and the distance (Dsp) between the two GdBCO bulk superconductors and a cubic permanent magnet PM3 is 0mm, The results indicate that the higher levitation force can be obtained by introducing PM-PM levitation system based on scientific and reasonable design of the hybrid magnetic levitation system, which is helpful for designing and constructing superconducting magnetic levitation systems.

Estimation of Airgap Length in Magnetically Levitated Systems

In this paper, a new technique for estimation of airgap length in magnetically levitated systems (MagLev) is introduced. The proposed method makes use of the embedded airgap information in the inductance of an active phase in a hybrid MagLev system. Terminal measurements are used along with the phase voltage equation to estimate airgap length by the virtue of an existing one-to-one correspondence between inductance and airgap length. Sensitivity analysis will be carried out to illustrate the impact of changes in MagLev's geometry and current sensor resolution on the accuracy of the proposed method. Based on experimental results, it will be shown that the proposed sensorless method performs well both at standstill and moving conditions.

2029 薄鋼板のハイブリッド磁気浮上システムに関する研究 : 永久磁石と鋼板間のギャップの最適化の検討(G05-4 移動体の運動と制御,G05 機械力学部門)

2029 薄鋼板のハイブリッド磁気浮上システムに関する研究 : 永久磁石と鋼板間のギャップの最適化の検討(G05-4 移動体の運動と制御,G05 機械力学部門)

Design, manufacture and performance evaluation of HTS electromagnets for the hybrid magnetic levitation system

A high speed electromagnetic suspension (EMS) maglev has emerged as the solution to speed limit problem that conventional high-speed railroad has. In the EMS maglev, small levitation gap needs uniform guide-way which leads to increase the construction cost. The large levitation gap can reduce the construction cost. However it is hard for normal conducting electromagnet to produce larger magneto-motive force (MMF) for generating levitation force as increased levitation gap. This is because normal conductors have limited rating current to their specific volume. Therefore, the superconducting electromagnet can be one of the solutions for producing both large levitation gap and sufficient MMF. The superconducting electromagnets have incomparably high allowable current density than what normal conductors have. In this paper, the prototype of high temperature superconducting (HTS) electromagnets were designed and manufactured applicable to hybrid electromagnetic suspension system (H-EMS). The H-EMS consists of control coils for levitation control and superconducting coils for producing MMF for levitation. The required MMF for generating given levitation force was calculated by both equations of ideal U-core magnet and magnetic field analysis using the finite element method (FEM). The HTS electromagnets were designed as double pancakes with Bi-2223/Ag tapes. Experiments to confirm its operating performance were performed in liquid nitrogen (LN2).

Research on magnetic force characteristics of the controlled-PM Maglev linear synchronous motor with finite element method

A controlled-PM Maglev system with permanent magnets and electromagnets excitation together can improve the lift/weight ratios, and reduce electromagnetic power consumption at the same air gap compared with a conventional electromagnetic attractive levitation system. It has been proved to be a very effective approach with great potential for application in magnetic levitation system. This paper analyses the magnetic force characteristics of linear synchron ous motor in a controlled-PM maglev model vehicle system in our lab with fi nite element method (FEM), presents the relationship between the magnetic forces and air gap at different current excitat ion, thrust-angle performance, and experiment results. Compared with an electromagnet, a permanent magnet has higher energy density. At present, high energy level of NdFeB can meet the need of most motor performances. If permanent magnets (PM) and electromagnets are combined to form hybrid magnets, the lift force could be increased effectively with the same air-gap length, and the vehicle weight could be decreased. In this hybrid maglev system, PM may provide the base support force required for levitation, while electromagnets produce adjustable support force to stabilize the levitation system. Thus there leads to an extensive reduction of the energy consumption by the vehicle. The rated power of the supply batteries and choppers for exciting current is reduced to a great extent. Since the lift force of the hybrid maglev

Influence of Auxiliary Permanent Magnet on the High-$T_{\rm c}$ Superconductive Hybrid Maglev System

The high-Tc superconductive (HTS) hybrid Maglev with the auxiliary permanent magnet (PM) is a useful method to improve the system load density and stiffness. The auxiliary PM changes the magnetic circuits and increases the instability of the Maglev system. To investigate the levitation performance, different HTS hybrid Maglev arrangements involving PM and bulk HTS were tested above the permanent magnet guideway. Some useful conclusions and reference for relative design can be found from the experimental results and analyses.

Experimental study of a PM-HTSC hybrid magnetic levitation system

Experimental study of a PM-HTSC hybrid magnetic levitation system

Performance comparisons of model-free control strategies for hybrid magnetic levitation system

The study mainly focuses on the development of three model-free control strategies including a simple proportional-integral-differential (PID) scheme, a fuzzy-neural-network (FNN) control and an adaptive control for the positioning of a hybrid magnetic levitation (maglev) system. In general, the lumped-parameters dynamic model of a hybrid maglev system can be derived from the energy balance. In practice, the mathematical model can not be established precisely because this hybrid maglev system is inherently unstable in the levitated direction, and the relationships between current and electromagnetic force are highly nonlinear. To cope with the unavailable dynamics, model-free control design is used to handle the system behaviour. In this study the experimental results of PID, FNN and adaptive control schemes for the hybrid maglev system are reported. As can be seen from performance comparisons, the adaptive control system yields favorable control performance superior to that of PID and FNN control systems. Moreover, it not only has a learning ability similar to that of FNN control but also the simple control structure of PID control.

A hybrid maglev vehicle using permanent magnets and high temperature superconductor bulks

A hybrid maglev vehicle using permanent magnets and high temperature superconductor (HTS) bulks is presented. Its guideway is composed of permanent magnets and soft iron. The HTS bulks provide partial levitation force and guidance force, and the onboard permanent magnets provide additional levitation force. Firstly, the levitation force of a single permanent magnet and a single HTS bulk over a permanent magnetic track is studied, the surface magnetic flux density of which is up to 1.2 T. Secondly, both levitation force and guidance force of two arrays of permanent magnets and HTS bulks are studied. Results show that the hybrid maglev vehicle using permanent magnets and HTS bulks has larger levitation force and stiffness.

Experimental study of a PM‐HTSC hybrid magnetic levitation system

Experimental study of a PM‐HTSC hybrid magnetic levitation system

Experimental study of a PM-HTSC hybrid magnetic levitation system

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

Calculation of the induced currents and forces for a hybrid magnetic levitation system

This paper presents the calculation of the induced currents and forces for a 3D nonlinear eddy current field problem with ferromagnetic moving conductors. The A/spl I.oarr/, V-A/spl I.oarr/ formulation is used in combination with four different gauging methods to stabilize the solution process. To consider nonrectangular shapes of geometries tetrahedral elements were employed. The computation procedure is applied to a hybrid magnetic levitation system of a contactless and frictionless conveyance system.

Experimental Consideration on PM-HTSC Hybrid Magnetic Levitation System

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.

Hybrid Vibration Control Using Superconductor as Levitation and Velocity Sensor and Application of H.INF. Control Theory.

A new method of using a high Tc superconductor as two functions of levitation device and velocity sensor is introduced. The levitated object is controlled with an electromagnet using the measured velocity signal, that is, the system involves a hybrid magnetic levitation of superconductor pinning effect and active magnetic bearing. The experimental setup of a single degree-of-freedom system is made using a cantilever beam. A coil is wound around a permanent magnet which is used as a velocity sensor, This coil produces electromotive voltage in proportion to relative velocity. In order to insulate against vibration from the base and to reduce vibration from external force an H∞ optimum controller is designed. A simple experimental setup is made and the results obtained are discussed in detail.

Trial Manufacture of a PMHTS Hybrid Maglev System.

Trial Manufacture of a PMHTS Hybrid Maglev System.