• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.729-730
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• 2008

Recently, contactless power transfer system is widely used in many industry applications such as automated guided vehicles and medical applications. In this paper, we derived electrical parameters and analyzed output characteristics of contactless power transfer device with resonant converter for levitation / propulsion system. And, the characteristics analysis results are satisfied with output required specifications of analysis model.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.263-264
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• 2010

본 논문에서는 동일한 전압, 전류 위상을 갖는 2개의 트랜스포머를 1개의 트랜스포머로 집적화하여 부피저감 효과를 갖는 IM 트랜스포머를 제안한다. 제안한 IM 트랜스포머는 하프브릿지 및 풀 브릿지 타입의 컨버터, 인버터에서 승압, 감압 및 절연을 위한 트랜스포머를 2개 이상 사용하는 경우에 하나의 트랜스포머로 집적화하여 외족 코어에서 자속을 상쇄시켜 코어부피가 저감되는 효과가 있다. 제안된 IM 트랜스포머는 이론적으로 분석하여 Gyrator model을 통해 모의실험 및 시작품 제작하여 46인치 LCD TV용 인버터에 적용하여 실험을 통해 우수성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.242-243
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• 2010

This paper investigates a power supply of medium voltage with enhanced ignition characteristics for plasma torch. Series resonant half-bridge topology is presented to be a suitable ignition circuitry. The ignition circuitry is integrated into the main power conversion system of a multi-phase staggered three-level dc-dc converter with a diode front-end rectifier. The plasma torch rated for 3MW, 2kA and having the physical size of 1m long is selected to be a high enthalpy source in waste disposal system. The steady-state and transient operations of plasma torch are simulated. The parameters of Cassie-Mary arc model are calculated based on 3D magneto-hydrodynamic simulations. Circuit simulation waveform shows that the ripple of arc current can be maintained within ${\pm}10%$ of its rated value under the existence of load disturbance. This power conversion configuration provides high enough ignition voltage around 5KA during ignition phase and high arc stability under the existence of arc disturbance noise resulting in a high-performance plasma torch system.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.12
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• pp.596-607
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• 2006

This paper presents Single Phase Switched Reluctance Motor (SPSRM) optimum design for vacuum cleaners using Response Surface Methodology (RSM) to determine geometric parameters, and the 2-D Finite Element Method (FEM) has been coupled with the circuit equations of the driving converter. Additionally, an optimum process for SPSRM has been proposed and peformed with geometric and electric parameters thereby influencing the inductance variation and effective torque generation as design variables. SPSRM performances have also been analyzed to determine an optimal design model for maximized efficiency at high power factor. In order to confirm the propriety of the Finite Element Method and motor performance calculation, simulation waveform and experiment waveform for motor voltage and current were compared.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.3
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• pp.35-42
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• 2017

This paper presents hardware implementation of background timing-skew calibration technique for time-interleaved analog-to-digital converters (TI ADCs). The timing skew between any two adjacent analog-digital (A/D) channels is detected by using pure digital Finite Impulse Response (FIR) delay filter. This paper includes hardware architecture of the system, main units and small sub-blocks along with control logic circuits. Moreover, timing diagrams of logic simulations using ModelSim are provided and discussed for further understanding about simulations. Simulation process in MATLAB and Verilog is also included and provided with basic settings need to be done. For hardware implementation it not practical to work with all samples. Hence, the simulation is conducted on 512 TI ADC output samples which are stored in the buffer simultaneously and the correction arithmetic is done on those samples according to the time skew algorithm. Through the simulated results, we verified the implemented hardware is working well.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.113-117
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• 1997

In this paper we detected the thrombosis formation by spectral analysis and neural network. Using microphone and amplifier, we measured the sound from the mechanical valve which is attached to the pneumatic ventricular assist device. The sound was sampled by A/D converter and the periodogram is the main algorithm or obtaining spectrum. We made the valvular thrombosis models using pellethane and silicon and they are thrombosis model on the disk, around the sewing ring and fibrous tissue growth across the orifice of valve. The spectrum of normal and 5 kinds of thrombotic valve were obtained and primary and secondary peak appeared in each spectrum waveform. So to distinguish the secondary peak of normal and thrombotic valve quantatively, 3 layer back propagation neural network.

• Journal of Power System Engineering
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• v.6 no.2
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• pp.73-81
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• 2002

In this study, electronically controlled automatic transmission adopted on a subcompact model in the market was modelled, and the driving performances of the transmission were simulated with the models. Kinetic and dynamic models of working components are established. The driving simulation program is developed with those models, and the various driving conditions are analyzed. With the results, the dynamic behaviour of the engine and the automatic transmission is easily understood. Especially, the transient performances of torque converter and clutches are deeply analyzed. Skipping the vehicle road test by using this analyzing tool, we can expect the cost down and the reduction of the development period of automatic transmission.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.11
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• pp.943-950
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• 2008

A novel nondestructive testing (NDT) system, which is able to detect a crack with high speed and high spatial resolution, is urgently required for inspecting small cracks on express train wheels. This paper proposes a high speed scan type magnetic camera, which uses the multiple amplifying circuits and the crack indicating pulse output system. The linearly integrated Hall sensors are arrayed in parallel, and the Hall voltages from each sensor in the scanning direction are obtained and amplified. High-speed NDT can be achieved by using the exclusive analog-digital converter and micro-processor because the ${\partial}\;V_H/\;{\partial}$ x value, which provides the most important crack information, can be obtained by buffering and calculating. The effectiveness of the novel method was verified by examine using cracks on the wheel specimen model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.1059-1066
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• 2003

A power generation system are proposed to convert ambient mechanical vibration into electrical energy using cantilever-type piezoelectric materials. The vibration-based power device can be used for self-powered systems without batteries. This paper presents the theoretical analysis for the coupled equations of piezoelectric and structural motions and investigates the dynamic characteristics of the self-power system using transfer function method. The theoretical model is verified by the finite element analysis of the resonance frequency, the dynamic response of the structure and the sensor sensibility. Experimental results measured using a prototype system agrees with the theoretical predictions. The system is shown to produce 2.53㎼ in average. Finally, we perform the optimal design for system variables to maximize output power.

• Nuclear Engineering and Technology
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• v.31 no.1
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• pp.1-8
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• 1999

In this paper, we propose a new type of power control system for the rod drive coil of the CEDM of the PWR NPP in order to supply more reliable DC power The electrical modelling of the controlled rod drive coil was done by referring related documentations. The design of the proposed system is based on this electric81 model satisfying the existing specification. A high power DC-DC converter scheme is adopted utilizing the SMPS technique in the design of the proposed system. In order to show the effectiveness of the proposed system, an experimental system with the capability of 3.2 K Watt was set up for a rod with four cores and some computer simulations and experimentations were carried out. The result shows a very similar tracking performance with that of the existing system to the driving command. As a result of this, the proposed method can be applied to the power control system for the rod drive coil of the CEDM of the PWR NPP.