نتایج جستجو برای: levitation

تعداد نتایج: 1853  

ژورنال: Journal of Railway Research 2019
Aghazadeh, Amir, Askarian Abyaneh, Hossein, Niazazari, Iman,

In this paper a new method is proposed for determining PID controller parameters in order to decrease losses in levitation system of magnetic trains. It is assumed that this system is a hybrid system and it consists of electric and permanent magnet. For optimization of losses initially AC losses of magnetic levitation system are calculated. Linear model of levitation system as well as modeling ...

Journal: :iranian journal of science and technology (sciences) 2014
a. hekmati

superconducting materials are capable of trapping extremely high magnetic fields. this property and meissner effect of superconductors causes a levitation force between bulk superconductors and a permanent magnet (pm). this levitation force has possible industrial applications such as permanent magnet guideways (pmg). because of the high price of permanent magnets, the optimization of pmg desig...

2014
Yanjun Yu Huangqiu Zhu Si Zeng

In order to decouple traditional levitation windings and armature windings, a new selfdecoupling magnetic levitation generator (SDMLG) is proposed for wind turbines. This new generator adopts double-stator structure. The armature windings are in the outer stator, and the levitation windings are in the inner stator. The rotor is made of a distributed hollow structure, so that it can effectively ...

2003

Magnetic levitation is becoming widely applicable in magnetic bearings, high-speed ground transportation, vibration isolation, etc., [1]. For example, magnetic bearings support radial and thrust loads in rotating machinery. In addition, magnetic suspension generates levitation action in rectilinear motion devices such as high-speed ground transportation systems. Magnetic levitation is immensely...

2001
M. D. Simon A. K. Geim

Stable levitation of one magnet by another with no energy input is usually prohibited by Earnshaw’s Theorem. However, the introduction of diamagnetic material at special locations can stabilize such levitation. A magnet can even be stably suspended between (diamagnetic) fingertips. A very simple, surprisingly stable room temperature magnet levitation device is described that works without super...

2008
Tomáš Hron

1. Introduction From the principal point of view, the magnetic levitation is a method which is used for suspending an object in the air, without any physical contact. There are few main types of the magnetic levitation – electromagnetic, electrodynamic, transformation, superconductive and diamagnetic. All these are usually based on the force interaction between magnetic field and gravitation fi...

Journal: :Mathematics and Computers in Simulation 2006
Tetsuzo Sakamoto Masaki Nakayama

This paper presents a modeling and simulation of a superconducting maglev vehicle with a levitation and guidance assist method we have proposed. The assist system stabilizes and assists the vehicle operation so that the vehicle does not need to depend on the mechanical wheels as much as possible at low speeds. By controlling the LSM armature currents, the auxiliary levitation and guidance force...

2015
Mohsen Honarjou H. Faraji A. Shirzadi

One maintenance task that still exist with conventional motors, are bearing lubrication and renewal. Bearingless motors are replaced with conventional motor that uses a magnetic levitation force to suspend a rotor without any mechanical contact. In bearingless motors, additional windings are wound together with motor windings in stator slots. In this paper, a bearingless permanent magnet-type s...

2015
A Patel S C Hopkins A Baskys V Kalitka A Molodyk B A Glowacki

Stacks of superconducting tape can be used as composite bulk superconductors for both trapped field magnets and for magnetic levitation. Little previous work has been done on quantifying the levitation force behavior between stacks of tape and permanent magnets. This paper reports the axial levitation force properties of superconducting tape wound into pancake coils to act as a composite bulk c...

2014
Zhongqiao Zheng Xiaojing Wang Yanhong Zhang Jiangsheng Zhang

In response to the uncertainty, nonlinearity and open-loop instability of active magnetic levitation control system, and neural network PID quadratic optimal controller are designed using optimum control theory. Introducing supervised Hebb learning rule, constraint control for positioning errors and control increment weighting are realized by adjusting weighting coefficients, using weighed sum-...

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