• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.220-224
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• 2005

EMU(Electric Multiple Unit) operated in local area is mostly consist of moving system on the rail and the traction motor drives the gear and wheel with the mechanical propulsion force. Most of countries are interested in Magnetic Levitation Vehicle for the transportation system on next generation and they have been studying about it continuously. Thus this paper is studied the Linear Induction Motor as the propulsion equipment of Magnetic Levitation Vehicle

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2001년도 학술대회 논문집
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• pp.61-64
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• 2001

Levitation force of a new magnetic levitation system using a super-conducting bulk magnet(SBM) and a permanent magnet(PM) was numerically calculated. The non-linear J-E relation of a SBM was modeled using a critical state model and iteration method, and demagnetization of a PM was considered using a demagnetization curve of a real PM. The maximum limitation of levitation force was found according to increasing the trapped field in a SBM. Finite element method was used for numerical calculation.

• 한국초전도ㆍ저온공학회논문지
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• 제10권1호
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• pp.37-41
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• 2008

본 연구에서는 초고속 자기부상열차의 개발을 위한 기초연구의 성격을 가지고 있는 고온초전도 자기부상자석의 최적 설계를 수행하였다. 고온초전도 자기부상자석은 임계전류, 발생자장, 지상도체 등을 고려하여야 하는데 3차원 수치해석법을 이용하여 권선의 구조를 설계하였다. 권선의 형태로써 더블팬케이크형 고온초전도 권선을 선택하였으며 일정한 길이의 초전도선으로 최적의 부상조건을 가지는 구조를 도출하였다. 본 연구에서 제시한 조건은 총 800m 고온초전도선을 사용하는 가정 하에 piece length 400m로 내경 100mm인 더블팬케이크형 코일 2개를 제작하여 직렬로 연결한 부상자석이다. 제작한 자석의 인덕턴스는 279.4mH였으며 임계전류는 42A 였다. 인덕턴스, 발생자장 모두 설계 시 제시한 계산 값과 일치하는 결과를 보여주었으므로 본 연구는 성공적으로 수행되었다고 할 수 있으며 본 결과는 향후 초전도 자기부상자석의 설계에 기초자료로 활용될 수 있을 것이다.

• 한국초전도ㆍ저온공학회논문지
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• 제19권1호
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• pp.30-35
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• 2017

The effects of the crystallographic orientation and sample thickness on the magnetic levitation forces (F) and trapped magnetic field (B) of single grain YBCO bulk superconductors were examined. Single grain YBCO samples with a (001), (110) or (100) surface were used as the test samples. The samples used for the force-distance (F-d) measurement were cooled at 77 K without a magnetic field (zero field cooling, ZFC), whereas the samples used for the B measurement were cooled under the external magnetic field of a Nd-B-Fe permanent magnet (field cooling, FC). It was found that F and B of the (001) surface were higher than those of the (110) or (100) surface, which is attributed to the higher critical current density ($J_c$) of the (001) surface. For the (001) samples with t=5-18 mm, the maximum magnetic levitation forces ($F_{max}s$) of the ZFC samples were larger than 40 N. About 80% of the applied magnetic field was trapped in the FC samples. However, the F and B decreased rapidly as t decreased below 5 mm. There exists a critical sample thickness (t=5 mm for the experimental condition of this study) for maintaining the large levitation/trapping properties, which is dependent on the material properties and magnitude of the external magnetic fields.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.623_624
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• 2009

This paper deals with the characteristic analysis of electro-magnet (EM)-permanent magnet (PM) hybrid levitation and propulsion device for magnetically levitated (maglev) vehicles. Several machine characteristics such as levitation force with/without control current and thrust are described. In order to verify the analysis results and feasibility of high-speed operation of the maglev vehicle, real-scale static test set is implemented and tested.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권6호
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• pp.342-350
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• 2003

In this paper, a levitation controller for a magnetic levitation(MagLev) system is designed and implemented. The target to be controlled is PEM(permanent and electromagnet) type with 4-corners levitation which is open-loop unstable, highly non-linear and time-varying system. The digital control system consists of a VME-based CPU board, AD board, PU board, 4-Quadrant chopper, and gap sensor, accelerometer as feedback sensors. In order to estimate the velocity of the magnet, we used 2nd-order state observer with acceleration and gap signal as input and output, respectively. Using the estimated states, a state feedback control law for the plant is designed and the feedback gains are selected by using the pole-placement method. The designed controller is experimentally validated by step-type gap reference change and force disturbance test.

• 한국초전도ㆍ저온공학회논문지
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• 제9권1호
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• pp.76-81
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• 2007

This paper deals with the characteristics of a small scale $high-T_c$ superconducting(HTSC) levitation system. The levitation tester. which models after electrodynamic suspension(EDS) maglev, consists of one HTSC magnet, a reaction plate, and force measuring components. Instead of moving magnet, AC current was applied to the fixed HTSC magnet. The magnet also has persistent current switch(PCS). The inductance of the magnet was 18.5 mH and total joint resistance of the magnet was $5.74{\times}10^{-7}\Omega$. AC current was applied into the HTSC magnet with various frequencies and the levitation force was calculated and measured. According to the increase of the vehicle speed, the levitation force was saturated.

• 한국정밀공학회지
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• 제21권11호
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• pp.91-98
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• 2004

TFLIM(Transverse Flux Linear Induction Motor), making its closed magnetic path with the direction of the traveling field orthogonal, had been developed to decrease an edge effect of the general induction motor. To control the levitation force and the thrust force on the secondary part of TFLIM independently, the various methodologies have been presented. When we try to achieve the independent control using only the multi-phase inputs assigned in the stator coils as an approach, in which condition we can minimize the coupling effect between two forces\ulcorner In this paper, we show the qualitative influence of a slip frequency, an ac magnitude, a dc offset superposed in the ac power, and a major parameter of TFLIM on the couple through the computer simulation. And to realize the independent motions between levitation and thrust motion without any auxiliary means fur isolation of the secondary part of TFLIM, the decouple compensator is suggested, including the experimental results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.482-487
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• 2001

This paper introduces a Lorentz force type four-pole self-bearing motor, where the new pole arrangement of a stator is intended to function both as a synchronous PM motor and as a magnetic bearing. The Lorentz force type has some good points such as linearity of control force, freedom from flux saturation, and high efficiency unlike conventional self-bearing motors. Mathematical expressions of torque and radial force are derived to show that they can be separately controlled regardless of rotational speed and time. To verify the proposed theory, a prototype is made, where a ring-shape outer is actively controlled in two radial directions while the other motions are passively stable supposing the radial stability. Through some experiments, it is shown that the proposed scheme can provide high capability and feasibility for a small high-speed self-bearing motor.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.358-362
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• 1999

Magnetic levitation forces and trapped magnetic fields of top-seeded melt growth-processed YBCO superconductors with multiseeding were studied. The number of seeds was varied from one to six. The surface magnetic field of the prepared YBCO samples was dependent on the number of the seeds. The trapped magnetic field of the top surface decreased with increasing the number of the seed. Particularly, it drastically decreased at the YBCO grain boundary, probably due to the weak rink nature of the boundary. The magnetic levitation force also decreased with increasing the number of the seeds, similar to the variation of the surface magnetic field.