Repulsive Magnetic Levitation Research Articles

Repulsive magnetic levitation-based electromagnetic energy harvesting of a low-frequency ocean wave

In this study, an electromagnetic energy harvester for a low-frequency ocean wave was developed in a compact 3D-printed structure. Ocean wave energy conversion technologies exist, but maintaining them in the harsh marine environment is crucial for business. Friction increases maintenance costs. Therefore, magnetic levitation, being friction-free, is used for cost-effective, low-maintenance electromagnetic energy harvesting applications. Low-frequency oscillating energy is captured using repulsive magnetic levitation with a buoy and generating electricity using a permanent magnet and copper coil. A levitating magnet is repelled by a fixed one, inducing electricity as it passes through a coil. Experiments with a 0.1 Hz sine wave mimic the average frequency of ocean waves, showing successful voltage peaks at intervals. The output voltage and measured power from the harvester exhibit variations influenced by multiple parameters. The maximum output voltage observed was 3.4 V and an average of 99 mW of power was calculated. The experiment demonstrates the feasibility of using repulsive magnetic levitation for low-frequency wave energy harvesting and also encompasses various harvester configurations, including transfer magnet forces and top magnets.

Stabilization of a Magnetic Repulsive Levitation Flywheel System Using a High-Efficiency Superconducting Magnetic Bearing

In this study, we developed a superconducting magnetic bearing using a permanent repulsive magnet. A repulsive magnetic levitation system with a permanent magnet can generate a strong levitation force in the absence of a power supply. However, it is unstable, except in the direction of repulsion. In contrast, superconducting magnetic bearings can generate a restoring force in all directions by utilizing the magnetic flux pinning property of the superconductors. Therefore, we constructed a superconducting magnetic bearing (SMB), which is stable along all axes without control, and has a strong axial levitation force, by combining a repulsive-type magnetic levitation system and a superconducting magnetic levitation system. We also reduced the amount of HTS used for the SMB and proposed an efficient method of using HTS. Furthermore, a driving test of the flywheel incorporating the SMB was conducted to verify the characteristics of the SMB. The experiment confirmed that the flywheel could overcome the resonance and drive the flywheel. In the drive experiment, the flywheel was driven up to 10,000 rpm.

Self‐tuning predictive control applicable to ship magnetic levitation damping device

In the ship design, there are strict vibration-proof requirements for precision instruments. Therefore, a ship repulsive magnetic levitation damping device is designed to achieve vibration reduction. And one self-tuning predictive control method is proposed to achieve the stable levitation of this device. Firstly, a predictive control (MPC) method with state constraints and input constraints is adopted to realise the stable suspension of the floater. The MPC can solve the problem of position imbalance of the magnetic levitation system under the external complex disturbances. Secondly, a self-tuning MPC method based on recursive least square is proposed to solve the problem caused by the fixed parameters of the traditional predictive controller. At the beginning of each control cycle, the recursive least-squares (RLS) method is used to estimate the parameters of the system. Thus, the optimal control model could be obtained for the current situation. Then, this model is applied to the predictive controller to solve the problem of parameter fixation in the traditional predictive control. Finally, the simulation results show that it can improve the accuracy, dynamic response and anti-interference performance obviously.

Examination of Vibration Damping Method by Controlling the Rigidity of Superconducting Magnetic Bearings

In this study, we developed a method to control vibration of a superconducting magnetic bearing flywheel using a repulsive levitation system that combines permanent magnets and coils. Generally, in the repulsive type magnetic levitation system using only permanent magnets, the repulsive force in the levitation direction is strong, but it is unstable in other directions. Therefore, the pinning effect of high-temperature superconductors is used to increase the stability. However, the resonance in the radial direction was large, and countermeasures were required. Thus, we propose a method to suppress the amplitude by changing the radial stiffness. In this method, we changes the current applied to the coil inserted between the repulsion magnets. This makes it possible to change the radial stiffness. Vibration is controlled by changing the stiffness at resonance point. The above vibration control method was verified by experiments, and the usefulness of this proposal was clarified.

Adaptive Control of Repulsive Magnetic Levitation System

Adaptive Control of Repulsive Magnetic Levitation System

Salient-Pole Deformation of a Floating Ring Permanent Magnet in a Low Stiffness Type Repulsive Magnetic Levitation Device and Its Levitation Characteristics

Salient-Pole Deformation of a Floating Ring Permanent Magnet in a Low Stiffness Type Repulsive Magnetic Levitation Device and Its Levitation Characteristics

Design and Optimization of a Magnetic Levitation Load Reduction Device for a Hydropower Unit

The construction of hydropower stations has been expanding in China as a result of economic development and the improvement of people’s lives. To save cost, the capacity of a single unit has been greatly increased, and many higher technical requirements have been presented for hydropower units, among which one of the key technologies is the thrust bearing. With the increase in single machine capacity, the pv value of the kinetic energy on the thrust bearing also increases, which will cause the bearing tile burning accident. Therefore, the thrust bearing needs to be designed to improve the bearing capacity. Instead of improving the traditional mechanical structure and using new materials, this paper proposes a levitation load reduction device for the thrust bearing to reduce the pv value of the kinetic energy on the thrust bearing. On the basis of kinetic energy analysis, the feasibility of the magnetic levitation load reduction device is analyzed. A repulsive maglev load reduction device suitable for hydropower units is designed; according to linear motor theory, a three-dimensional analytical model is established to analyze the levitation force, and an analytical calculation method is given. A finite element simulation model is built to study the effects of the primary electrical parameters, structural parameters, and material properties on electromagnetic forces, and the effect rules and the methods of optimal design are given. A small-scale prototype was developed, then tests were conducted to verify the feasibility and accuracy of the design and mechanism.

Performance Evaluation of a Newly Proposed Repulsive Type Magnetic Levitation System with Low Magnetic Stiffness

Performance Evaluation of a Newly Proposed Repulsive Type Magnetic Levitation System with Low Magnetic Stiffness

Control conmutado para un sistema de levitación magnética con atascamiento-deslizamiento

Magnetic levitation systems can be used in many applications such as precise positioning. Repulsive configurations are open-loop stable and offer other interesting characteristics. However, these applications may present stick-slip effects due to the friction forces. The combination of the highly non-linear magnetic forces and the stick-slip effects result in a complex control problem. This article presents the identification, model analysis and control system design for an experimental repulsive magnetic levitation system. The design is based on the principles of state feedback linearization. In previous reports it was shown that the performance of feedback linearization control of similar devices is degraded by the parameter uncertainty introduced by the friction. In this work, the performance of the feedback linearization control is improved by adding an outer-loop linear controller with integral action. This controller was designed according to classical frequency analysis. Experimental results show better transient responses and low steady state errors. Nevertheless, the integral action and the friction force increase the stick-slip oscillations. Stick-slip motion is eliminated through a switching control strategy based on the experimental characterization of the stick-slip sliding surface. The resulting control scheme allows preserving the low steady state error of the integral control law and eliminates the stick-slip motion. This is accomplished through a relatively simple controller when compared with previous reports. Experimental results show the effectiveness of the proposed scheme.

Proposal of permanent magnet repulsive maglev transportation system: possibility of automobile with magnetic levitation

AbstractThis paper describes a maglev transportation system for automobiles. The track is an array of permanent magnet blocks, and the levitating body is the bedplate which consists of permanent magnet plates, propulsion coils, levitation coils, and guidance coils. The feature of this system is that an automobile equipped with the bedplate is free to approach into the track or to swerve from the track by using four wheels with the lift. The force acting on the levitating body is calculated on the assumption that each permanent magnet can be expressed as a surface current. From the calculation results, it is proven that an automobile of 4.35 m length, 1.8 m width, and 1700 kg weight can run at a speed of 500 km/h against the air resistance force of 3704 N on the condition that the battery has an output of 337.5 V and a capacity of 190 Ah. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(3): 65– 76, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20491

504 反発型磁気浮上装置のセルフパワード・アクティブ振動制御

磁気浮上系は非接触なため、摩擦、磨耗、騒音の心配がない利点を持ち、磁気軸受け、クリーン性を要する環境の搬送装置、高速の磁気浮上車などに適用されている.反発型の磁気浮上系は静的には安定であるが、十分な散逸エネルギが得られないため、動的な安定性はあまり期待できない.コイルをアクチュエータとして扱うアクティブ制御は、パッシブより良好な制振特性を示すが、アクティブ制御は外部エネルギを消費する欠点がある.また、アクティブ制御を行う際に、エネルギを回生し、その回生したエネルギを用いて制御を行う、セルフパワード・アクティブ制御が提案されている.本研究では永久磁石反発型の一自由度系モデルの装置を用い、アクティブ制御の外部エネルギに代わり、アクチュエータから電磁気的に回生した振動エネルギを使用する. 実験装置には、リニアガイドに沿って上下運動をすることができる浮上体に、コイルが取り付けてある.そのコイルがアクティブ制御を行うアクチュエータとエネルギ回生を行うジェネレータの役割をする.制御系設計では、最適制御理論を用いた.浮上体の振動を抑えるために浮上体の速度に重みをかけ、地面との接触を避けるために相対変位に重みをかけた評価関数を用いた.セルフパワード・アクティブ制御において、コイルに流れる電流を目標電流に近づけるため、モードを切り替えている.各モードには、エネルギ回生モード、ブレーキモード、力行モードがある.図A1のコイルオープンとセルフパワード・アクティブ制御の浮上体絶対変位のパワースペクトル密度を比較すると、セルフパワード・アクティブ制御を行ったときの浮上体絶対変位が抑えられていることがわかる.また、図A2のコイルオープン、アクティブ制御、セルフパワード・アクティブ制御の浮上体絶対変位のRMS値からも、同様に、セルフパワード・アクティブ制御時に抑えられていることがわかる.永久磁石反発型磁気浮上装置を用い、ランダム波を外乱として加えたときのセルフパワード・アクティブ振動制御を行った結果、セルフパワード・アクティブ制御の動的安定性をコイルオープン時より向上させることができた.さらに外部からのエネルギの供給をせずに、アクティブ制御に近い制振特性も得られることを示すことができた.

Proposal of Permanent Magnet Repulsive Maglev Transportation System-Possibility of Automobile with Magnetic Levitation-

This paper describes a maglev transportation system for automobile. The track is an array of permanent magnet blocks, and the levitating body is the bedplate which consists of permanent magnet plates, propulsion coils, levitation coils and guidance coils. The feature of this system is that the automobile equipped with the bedplate is free to approach into the track or to swerve from the track by using four wheels with the lift. The force acting on the levitating body is calculated on the assumption that each permanent magnet can be expressed as a surface current. From the calculation results, it is proven that the automobile of 4.35m length, 1.8m width and 1700kg weight can run at speed of 500km/h against the air resistance force of 3704N on the condition that the battery has an output of 337.5V and a capacity of 190Ah.

A novel dual-axis repulsive Maglev guiding system with permanent magnet: modeling and controller design

In this paper, we extend our previous result (1999, 2000) on designing a single-axis Maglev guiding system to a more involved task of designing a novel dual-axis positioning system. First, important issues related to construction of the mechanism of the dual-axis positioning system are addressed. Then, the dynamics of the dual-axis Maglev guiding system are analyzed. According to the derived analytic model, which is subject to unknown system parameters, an adaptive controller that can control the carrier at the desired target point of each axis with full alignment is presented. From the experiment results, a good performance in terms of regulation of the guiding-axis and tracking of the positioning-axis is achieved. This validates the design of the system hardware and demonstrates the feasibility of the developed controller.

Novel Design and Control Application to a Planar Maglev System

In this paper, a prototype of a novel planar maglev positioning system is proposed. It is a repulsive maglev system with a carrier and a matrix of the coils. Then, its analytical model is derived and analyzed. Next, an adaptive controller is to develop to deal with the unknown parameters with the objective of regulating the 6 DOFs in this system. From the simulation results, satisfactory performances including regulation accuracy and control stiffness have been demonstrated.

725 回生されたエネルギによる反発型磁気浮上系の振動制御

A repulsive magnetic levitation requires an active vibration control for dynamic stability, because it is not obtained enough dissipative energy. However, active control has a drawback to consume external energy. In this study, it was used that regenerated energy as electric power obtained by motion of actuator instead of external energy, for control of a 1-DOF magnetic levitation system using repulsive of permanent magnet. According to the experiment, performances of vibration are improved by the proposed system.

DESIGN AND CONTROL OF A NOVEL PLANAR MAGLEV POSITIONING SYSTEM

This paper describes a novel planar repulsive maglev prototype. In this maglev system, the carrier is levitated by a planar 2D array of coils. The levitation forces are due to repelling between the magnets and the coils. Then, the general model of motion of the carrier with complete degree of freedoms(DOFs) is derived and analyzed. Next, for the sake of control, a PID controller is designed here to regulate the all DOFs of the planar maglev system. From the simulation results, satisfactory good performances including stiffness and precision have been demonstrated. The experiment of the proposed system is under preparation.

338 ゲインスケジューリングによる反発形磁気浮上装置の制御(アドバンスト制御理論応用III)(OS アドバンスト制御理論応用)

In this article, we discuss control of a repulsive type magnetic levitation system. First we show a experimental result by using a LQG controller. Next we try to achieve levitation control by means of the gain scheduling technique. Here we describe the repulsive type magnetic levitation system as a linear systems with a scheduling parameter and design a scheduled controller for the linear system with a scheduling parameter.

Adaptive nonlinear control of repulsive maglev suspension systems

Magnetic levitation systems have recently become the focus of many research interests not only because they are most suitable for high-precision engineering applications but also because of the fact that they represent a difficult challenge to control engineers. As a result, most previous studies have focused on the control stabilization problem. In this paper, the issue of performance with respect to uncertainty in order to achieve a desired stiffness is addressed. The proposed controller is an adaptive backstepping controller. The adaptive backstepping controller provides system stability under model uncertainty, and achieves the desired servo performance. The experiments show that the proposed control achieves a superior behavior than other control.

Passive Repulsive MagLev: Concept and Experimental Demonstration

A simple demonstrator for a magnetic levitation vehicle (MagLev) based on repulsive suspension forces generated by permanent magnets is presented. The lateral and yaw motions are stabilized using controlled electromagnets. A mathematical model, aimed mainly at defining the control strategy, has been developed and then experimentally validated using the demonstrator. Two different control strategies have been tested, namely a zero position error and a zero average current control strategy. Both proved to grant a stable behaviour and to effectively counteract external force disturbances. This demonstrator will be used in future research on MagLev vehicles but also on magnetic suspensions in general.

Design, implementation and self-tuning adaptive control of maglev guiding system

This paper presents a self-tuning adaptive control (STA control) for a magnetically levitated (maglev) guiding system. The guiding system is a repulsive maglev system with a passive carrier and four active guiding tracks. Hybrid magnets exert the levitation forces, whereas the stabilizing forces are produced by electromagnets. Given such a system, an STA stabilizing controller is developed, and the thorough analysis of the stability property is also proposed. It is shown that without precise knowledge of various components, the overall system stability and the regulating precision are assured, which validates the hereby proposed system. From the simulation and experimental results, the performance of the system design and the enforced control mechanism is demonstrated successfully.