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Proceedings ArticleDOI

A Study of Different Possible Switched Mode Chopper Circuits for Multi-Magnet Based DC Electromagnetic Levitation System

TL;DR: In this article, an overview of power amplifier for multi-magnet based DC electromagnetic levitation system has been presented and the general requirement of power amplifiers for levitation systems has been described.
Abstract: In this paper an overview of power amplifier for multi-magnet based DC electromagnetic levitation system has been presented The general requirement of power amplifier for levitation system has been described The proposed multi-magnet based single axis levitation scheme has been described in brief Different possible switched mode power circuits for the multi-magnet based electromagnetic levitation system have been discussed and a comparative study has been made of the different topologies of power amplifiers based on their structure and practical results that derived from the proposed experimental set-up In the actual work design, fabrication and testing of multi- magnet based electromagnetic levitation scheme has been made as a complete project But in this paper the emphasis is given on the power amplifier portion due to limitation of space
Citations
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23 Oct 1973
TL;DR: In this paper, the rotor is made in the form of a rod placed between the poles of the electromagnets of an n-phase system, which can be used in gravimetry and gyroscopic devices.
Abstract: : The electromagnetic suspension suggested differs from known suspensions in that its rotor is made in the form of a rod placed between the poles of the electromagnets of an n-phase system. This invention can be used in gravimetry and gyroscopic devices. (Author)

16 citations

References
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Journal ArticleDOI
TL;DR: In this article, a single input single output (SISO) analytical model and closed-loop identification experiments are presented, with emphasis on design procedures of H/sub 2/ and H/ sub /spl infin// controllers applied to the electromagnetic levitation system.
Abstract: Many magnetically levitated transport systems have been constructed, tested, and improved. Various magnetic levitation (MagLev) system technologies are being developed, and some of them, including the prototype featured in this article, use electromagnets for vehicle levitation. Vehicle levitation is achieved by controlling the gaps of these electromagnets. The constructed prototype will have independent levitation and propulsion systems, but the focus of this article is on the levitation system only. The system is open-loop unstable, highly nonlinear, and it has a very restricted equilibrium region. A single input single output (SISO) analytical model and closed-loop identification experiments are presented, with emphasis on design procedures of H/sub 2/ and H/sub /spl infin// controllers applied to the electromagnetic levitation system. For the designs of these controllers, a special choice of weighting functions is employed to attenuate the resonance peak at low frequencies in the closed-loop system. The results show that closed-loop system responses with H/sub 2/ and H/sub /spl infin// controllers are very similar and present better performances when compared to the response obtained with a classical controller.

78 citations


"A Study of Different Possible Switc..." refers background or methods in this paper

  • ...Thispaper reports control ofan electro magnetically levitated platform (vehicle structure) [ 6 ]that usesfour attraction typemagnets fixed atthefour corners oftheplatform....

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  • ...topology (Fig. 6 ), itmaymakesense toinvest onanother simple circuit tocontrol thedumpcapacitor voltage within desired limits ortofeed backthis energy toinput supply....

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  • ...Instead ofthispowercircuit topology, ifthe simplified circuit (Fig. 6 ) withonlyoneswitch (anda diode withenergy-dump circuit) permagnet isused, the overall saving inthepoweramplifier components maybe significant....

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  • ...Thecommonsource point canbedirectly connected tothecontrol ground andgate driveisolation isnota musthere.Fig.7 showsa modification overthecircuit ofFig. 6 tokeepthe capacitor voltage magnitude undercontrol andnearly ripple free....

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  • ...Ineachcasethecurrent of theelectromagnet iscontrolled through asingle switch based DC toDC switched modechopper circuit (Fig. 6 ) utilizing anouterposition control loopandaninner current feedback control loopasshownintheblock diagram ofFig. 1.A leadcompensator [8]isusedin cascade withtheposition control loopformaintaining overall closed loopstability....

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Journal ArticleDOI
TL;DR: In this paper, two major demonstration systems are now in operation, one in Germany and one in Japan, for electrodynamic suspension and levitation, following on from aircushion vehicles such as the Tracked Hovercraft and the Aerotrain.
Abstract: Defying gravity seems to have fascinated scientists and philosophers through the ages. Electromagnetic suspension and levitation, following on from aircushion vehicles, such as the Tracked Hovercraft and the Aerotrain, has been the focus of attention and research for passenger-carrying vehicles since the 1970s. Two major demonstration systems are now in operation : one in Germany and one in Japan. Besides application to passenger-carrying vehicles, controlled DC electromagnet technology has been applied to produce frictionless magnetic bearings, conveyor systems, flow meters, etc. This is becoming a rapidly expanding area, moving out of the realms of academe into one of considerable industrial importance. The applications now include high-speed machine tool spindles, ultra-centrifuges, turbo-alternators, corrosive-liquid pumps, gas compressors and high-vacuum pumps, fly wheels for energy storage, handling components for protective coating and weighing balances. New developments in superconducting materials have also aroused fresh interest in the electrodynamic levitation schemes such as the Japanese one.

72 citations


"A Study of Different Possible Switc..." refers background or methods in this paper

  • ...Based on the basic principle, magnetic levitation may broadly be classified into two types, electrodynamic levitation and electromagnetic levitation [1-2]....

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  • ...In contrast, the explicit DC method, technically known as the DC electromagnetic levitation system (EMLS) [1-3], has a considerably simpler configuration with favourable power requirement....

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  • ...The expected variation in the magnet demand current (small signal component), over its nominal DC value, is expected to be band limited to around 10 Hz but it is better to have a current tracking capability in the range of up to 100 Hz [1]....

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  • ...In electromagnetic levitation (attraction system), the electromagnets are driven either by AC or DC source [1-2]....

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Journal ArticleDOI
TL;DR: A modified class-G linear amplifier has been developed to improve the overall efficiency of a transconductance amplifier loaded with the high inductance and low resistance typical of the magnetic bearing coils.
Abstract: A modified class-G linear amplifier has been developed to improve the overall efficiency of a transconductance amplifier loaded with the high inductance and low resistance typical of the magnetic bearing coils. A simple theoretical characterization has been used to provide some diagrams to optimize the power efficiency as a function of a nonconstant load such as that due to a rotor unbalance. Experimental results are reported that show a more than satisfactory agreement with the expected results and the developed theory.

34 citations


"A Study of Different Possible Switc..." refers background in this paper

  • ...Fig. 4 Asymmetrical bridge (H-bridge) converter circuit...

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  • ...Theasymmetrical bridge circuit showninFig. 4 ...

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