• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.12
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• pp.2343-2351
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• 2007

In this paper, we describe the design and implementation of time-varying magnetic field stimulator. Novel design for power supply part to generate high repetitive magnetic field for very short time(less than $300{\mu}s$) was achieved. Using the novel designed power supply part and the circular type coil probe, we've achieved high magnetic field up to 1.2 Tesla in 20Hz repetition rate.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.2
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• pp.227-230
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• 2009

In this paper, we performed the optimum design of reactors for matrix-type superconducting-fault current limiters (SFCLs), using electromagnetic analysis tools. We decided a optimun position within a reactor for superconducting elements of current-limiting parts and trigger parts from the calculation of magnetic flux internsity for reactor structures. Also we decided effective distance length between two reactors through the analysis of the distribution of magnetic field, according to distance lengths between them. We designed and characterized matrix-type SFCLs, based on our optimum design of a reactor. We confirmed uniform distribution of a fault current, resulted from the improvement of simultaneous quench characteristics within our matrix-type SFCL.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.71-74
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• 2000

The equi-potential lines designed in the electric field are introduced to find the preform shape in axisymmetric hot forging. The equi-potential lines generated between two conductors of different voltages show similar trends of the minimum work paths between the undeformed shape and the deformed shape. Base on this similarity the equi-potential lines obtained by arrangement of the initial and final shapes are utilized for the design of preform and then the artificial neural network is used to find the range of initial volume and potential value of the electric field.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.23-24
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• 2013

In recent years, ISG (Integrated Starter and Generator) system receives a great attention for electric electrification of normal gasoline vehicle. As a cost-effect machine design, an ISG without a permanent magnet is considered. A 12slot-10pole field-excitation flux-switching synchronous machine (FEFSSM) is designed and analyzed via JMAG. The active parts such as the field excitation coil and armature coil are located on the stator. The rotor part consisting of single piece iron makes it more robust and suitable to apply for high speed motor drive system application coupled with reduction belt. The design target is the motor with a maximum torque of 40Nm, a maximum power of 10kW and a maximum speed of 14000 rpm. In this paper, design optimization method is proposed for high torque capability.

• Journal of Hydrogen and New Energy
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• v.20 no.6
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• pp.492-498
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• 2009

Six sigma methode was applied for optimization of flow field design of a proton exchange membrane fuel cell (PEMFC). The optimization between number of channel and channel/rib width was suggested in this paper with six sigma method. With the help of six sigma design of experiment (DOE) the number of experiments may be reduced dramatically. The fuel cell channel design optimization with results of these experiments with a 100 $cm^2$ serpentine flow field indicates a optimization data for a given constant operating conditions.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.113-115
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• 2007

This paper presents a design notch to reduce cogging torque of interior type permanent magnet motor. As design notch on rotor of IPM motor, magnetic field from between rotor and teeth of state is changed. By reason of variation magnetic field, cogging torque is generated. Through Fourier formulation of magnetic field on rotor, we found position of notch and manufactured armature that is designed by optimizing analysis. The validity of the proposed design is confirmed with experiments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.923-929
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• 2004

A magnetostrictive sensor is a sensor measuring elastic waves. Because of its unique non-contact measurement feature, the sensor receives more attentions in recent years. These sensors have been mainly used to measure longitudinal and torsional waves in ferromagnetic waveguides, but there increases an interest in using the sensor for flexural wave measurement. Since the performance of the sensor is strongly influenced by the applied bias magnetic field distribution, the design of the bias magnetic system providing the desired magnetic field is critical. The motivation of this investigation is to design a bias magnetic system consisting of electromagnets and yokes and the specific objective is to formulate the design problem as a bias yoke topology optimization. For the formulation, we employ linear magnetic behavior and examine the optimized results for electromagnets located at various locations. After completing the design optimization, we fabricate the prototype of the proposed bias magnetic system, and test its performance through flexural wave measurements.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.99-102
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• 2006

Optimal flow-field design of bipolar-plates for a commercial class PEM(polymer electrolyte membrane) fuel cell stack was carried out on the basis of three-dimensional computational fluid dynamics(CFD) simulation. A three-dimensional CFD model originally developed by Shimpalee et al., has been utilized for performing large-scale simulation of a single fuel cell consisting of bipolar-plates gas diffusion layers, and a membrane-electrode-assembly(MEA). The CFD model is able to predict the current density, pressure drops, gas velocities, vapor and liquid water contents, temperature distributions, etc. inside a single fuel cell. Depending on simulation results from the CFD modeling of a PEM fuel cell, several flow-fields of bipolar-plates were designed and verified. The final design of the bipolar-plate has been chosen from the simulations and experimental tests and showed the best performance as expected from the simulation results under a normal operating condition. Thus, the CFD simulation approach to design the optimal flow-field of the bipolar-plates was successful. The final design was adopted as the best flow-field to build a commercial scale PEM fuel cell stack, the performance of which shows about 42% higher than that of the older bipolar-plate design.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.696-698
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• 2004

In this paper we design $H_{\infty}$ infinity controller for Induction motor with low speed operation. $H_{\infty}$ controller is applied in order to design a state feedback static controller for field oriented control of an induction motor. $H_{\infty}$ controller are linear plant can be set up using the same assumptions that are at the basis of field oriented control. Thus, $H_{\infty}$ control theory can be successfully used to set up a state feedback controller for field oriented control of an induction motor. The performances of the $H_{\infty}$ controller is numerically analysed and experimentally verified to prove the validity of the design procedure. In this paper show that performances with high robustness to variations of system parameter.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1026-1031
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• 2008

We report on the design and experimental results of a large diameter faraday rotator for the high-power laser system(KLF: Kaeri laser facility) that was completed in late 2007s at Korea Atomic Energy Research Institute. The design involves modelling the magnetic field of cylindrical coil with large diameter(110 mm). Magnetic field generation coil is designed by 6 layers using a rectangular wire with cross-sectional area $3{\times}5[mm^2]$. We obtain an isolation ratio for optical feedback of 35 dB at 1064 nm and magnetic field strengths ${\sim}25kG$. We expect that the design can be widely used optical isolators in high-power laser system.