• 한국산업정보학회논문지
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• 제18권2호
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• pp.13-18
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• 2013

The authors designed a high temperature superconductor (HTS) racetrack coil for a 10 MW class superconducting synchronous wind turbine generator. The designed HTS racetrack coil was analyzed by an electromagnetic finite element method (FEM) to determine the magnetic field distribution, inductance, stress, etc. This paper describes the stress analysis and structure design result of the HTS racetrack coil for 10 MW class superconducting synchronous wind turbine generators, considering orthotropic material properties, a large magnetic field, and the resulting Lorentz force effect. Insulated HTS racetrack coils and no-insulation HTS racetrack coils were also considered. According to the results of the stress analysis, the no-insulation HTS racetrack coil results were better than the insulated HTS racetrack coil results.

• 한국초전도ㆍ저온공학회논문지
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• 제16권1호
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• pp.27-31
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• 2014

2G HTS tapes are widely used for various electric machines. In addition, stacked or parallel connected HTS tapes are essentially used to raise transport current level for large capacity electric machines. Therefore, critical current characteristic of stacked tapes need to be studied. Recently developed 2G HTS tapes are fabricated with various defects doping so that tapes possess pinning center to improve the critical current characteristic. During this process, the critical current is determined minimum value in not perpendicular magnetic field but a specific magnetic field angle according to the reported research. However, the effects of magnetic field angle to critical current of multi-stacked 2G HTS tapes have not been examined. In this paper, field coil which is a race-track coil wound by using an HTS tape with iron-core was fabricated to apply angle adjustable magnetic field to the 2G HTS tape samples. We measured critical current of single and multi-stacked two tapes that have different characteristic depending on various magnetic field angle and magnitude in liquid nitrogen environment. Furthermore, results of single and multi-stacked tapes were compared and analyzed.

• 한국초전도ㆍ저온공학회논문지
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• 제15권4호
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• pp.48-52
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• 2013

This paper compares the features of second generation (2G) High Temperature Superconducting (HTS) field coil with those of magnesium diboride ($MgB_2$) field coil for a 10 MW class superconducting generator. Both coils can function effectively in their respective magnetic flux density range: 10-12 T for 2G HTS field coil, 2 T for $MgB_2$ superconducting field coil. Even though some leading researchers have been developing 10 MW class superconducting generator with 2G HTS field coil, other research groups have begun to focus on $MgB_2$ wire, which is more economical and suitable for mass production. However 2G HTS wire is still appealing in functions such as in-field property and critical temperature, it shows higher in-field property and critical temperature than $MgB_2$ wire.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2001년도 제6차 학술대회 초록집
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• pp.174-174
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• 2001

Purpose： Dimensions of body RF coil composed of 4 rectangular loops for low field open MRI hav been optimized. The design result shows the field inhomogeneity of B1 field below 1.5 dB in the 25 cm DSV can be achieved. Method： Our low field RF coil is composed of 4 rectangular strip loops that assumed to b located at both the bottom and top sides of permanent magnet. All the loops have identica dimensions and current amplitude. First, the inductance of a loop is calculated. Second, the current distribution on the coil strip is calculated by using finite difference time doma method (FDTD). It takes as much as 4 days in FDTD simulation for low frequency RF field That's why the electrical dipole radiation method is used for simulation. With the curren distribution obtained using the FDTD simulation, for various dimensional parameters th magnetic field has been calculated by electric dipole radiation method, where the curren elements are regarded as electric dipole radiation sources. The field pattern from electri dipole radiation is almost same as that from FDTD simulation. Also, it is same as that fro the result using the Viot-Savart equation, for far tone radiation term becomes zero and th Bl field amplitude of near one radiation is the same as the B field due to static current The field homogeneity is calculated in the 25 cm BSV.

• 한국전자파학회논문지
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• 제11권7호
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• pp.1194-1203
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• 2000

1 mG부터 5 G까지 발생시킬 수 있는 소동물 실험율 60Hz 자계 발생장치를 설계하고 제작하였다. 동시에 많은 동물을 시험하기 위해서는 발생장치 내의 균일한 자계 분포 영역이 넓어야 하는데, 본 고에서는 SD-계쥐 약 50마리를 수용할수 있도록 하기 위해 소동물의 거주 공간을 장치 내부 1$\times$1$\times$1m3 크기로 하고 전체 발생장치의 크기는 1.8$\times$1.8$\times$1.8m3 입방형으로 설정하였다. 장치 내부의 자계 균일도를 검증하기 위해서 3차원 자계 계산 프로그램을 개발하였고, 이를 이용하여 거주 공간의 자계 분포가 가장 균일하게 되는 내.외곽코일의 최적 전류비 및 위치를 결정하였다. 또한 수치계산을 통한 임피던스에 근거하여 전원장치를 제작하였다. 제작된 자계 발생장치는 측정을 통하여 동물 거주 공간의 자계 최대치와 최소치의 차이가 3% 이내임을 확인할수 있었고 정밀한 소동물 자계 노출 시험용으로 사용 가능한 것으로 판단되었다.

• Journal of electromagnetic engineering and science
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• 제11권4호
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• pp.298-303
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• 2011

A capsular endoscope (CE) for inspection of the large intestine requires a motor for backward navigation against the autonomous travel in the intestine. This study proposes an HF power system for generating a magnetic field and for delivering wireless power to the internal or implanted medical devices. The magnetic field is generated by a wound coil (L) around a wooden frame, and the current is driven to the coil through a resonating capacitor (C). The characteristics of the resonance frequency shifting of the L-C series circuit are analyzed. A stable magnetic field intensity in the field coil is maintained by a specially designed frequency tracking system that automatically follows the L-C resonance frequency. Testing confirmed that the oscillation system tracks well the parameter changes of the electric components caused by the operating conditions or environmental variations.

• 한국군사과학기술학회지
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• 제18권3호
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• pp.244-252
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• 2015

This paper describes design and construction results of the measurement system developed on the purpose of measuring properties of AC magnetic field sensors used in the weapon system. The system for measuring the properties of AC magnetic field sensors consist of 3-axis helmholtz coil, signal generator, signal amplifier, sensor data acquisition unit and AC magnetic field sensor property measurement & analysis equipment including the operating software. By using this system, we can measure various properties of AC magnetic field sensor such as sensitivity, linearity and dynamic response in the frequency from 1 Hz to 10 kHz. Finally we also verified its performance by measuring the property of a MAG 639, standard magnetic field sensor of bartington instruments, with the developed measurement system.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2003년도 한국우주과학회보 제12권2호
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• pp.63-63
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• 2003

There are many actuators and sensors used for attitude control system for KOMPSAT such as Reaction Wheel Assembly, Magnetic Torque Assembly, Dual Thruster Module, Solar array Drive, Three Axis Magnetometer, Conical Earth Sensor, Fine Sun Sensor Assembly, Coarse Sun Sensor Assembly, Gyro Reference Assembly and so on. For KOMPSA T satellite it has been considered using the Magnetic Torquer (MTQ) generating the magnetic dipole moment. In general, the magnetic dipole moment for satellite attitude control system is used for dumping out the excessive reaction wheel momentum so that the reaction wheel speed is not saturated. The objective of this study is to analyze the magnetic field characteristics generated by the Magnetic Torquer using the Maxwell 2D Field Simulator software. Currently, the developing model (DM) of the MTQ is being developed and manufactured at a company under the supervision of KARL MTQ is an electromagnet consisting of a ferromagnetic cylindrical core on which an excitation coil is wound. A current is passed through the coil to produce a dipole momentum in the ferromagnetic core. The configuration of the MTQ will be introduced in the presentation. The 2 dimensional model of the MTQ is drawn as axisymmetric models in RZ plane, and each corresponding material is assigned to the each MTQ object, the core, coil, and background. After the boundary conditions, current sources, and solution parameters are set up, the magnetic field intensities, directions, and other values specified by users can be calculated by using the finite element analysis. The theoretical magnetic field quantities obtained by the Maxwell 2D Simulator can be used for the basis of the development of the MTQ.

• 대한전기학회논문지
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• 제34권1호
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• pp.38-43
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• 1985

Since the superconductor type II with high critical current and high critical magnetic field was discovered in 1961, there were many studies on the superconducting coil for high field and highly homogeneous field. The graphical method and the numerical method by Newton Raphson technique have been studied as the method for design of homogeneous superconducting coil. It is comparatively easy to get a compensating coil for any given main coil by the above methods, but it is too laborious to get a general solution for main coil dimension. This paper studies the optimal design method for minimum volume of superconducting coil under certain central field and highly homogeneous field. The present method makes use of the nonlinear programming for optimization. The optimal solution of NMR superconducting coils by this method are demonstrated very well.

• 한국통신학회논문지
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• 제40권2호
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• pp.349-354
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• 2015

본 논문은 차량감지를 위해 자기센서를 이용하여 자기신호를 측정하고 형상을 분석한 결과에 관한 것이다. 자기센서는 하니웰사의 MR센서를 이용하였고, 센서의 성능을 알아보기 위해 3축의 길이가 1.2 m인 자기장 발생장치를 제작하여 자기장 감지능력을 측정하였다. 차량감지는 주행차로와 비 주행차로에 센서를 설치한 후 감지여부와 차체의 크기가 다른 7개 차량에 대해서 자기장을 측정하였다. 또한 SUV와 소형 차량의 주차구역과 비 주차구역에 센서를 설치하고 자기장 형상을 분석하였다. 마지막으로 차량의 각 부분별 자기장 형상을 측정하였다. 측정 결과 주행차로에 자기장 형상은 비 주행차로의 경우보다 자기장 첨두치가 크며 복잡한 형상을 보여 센서의 설치 위치로 주행차로와 주행차의 방향을 구분할 수 있었으며, 차체가 클수록 자기장의 변화가 커서 차량 종류를 식별할 수 있었다. 또한 차량의 각 부분별 자기장의 변화를 측정하여 형상을 분석하였다.