• 한국정보처리학회논문지
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• 제7권2호
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• pp.470-476
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• 2000

본 논문은 소자 수준의 설계방법 보다아키텍쳐와 같은사위수준의 설계방법을 적용하여 IP(Intellectual Property)에 활용하기 적합한 저전력 마이크로콘트롤러 코어 설계를 다루었다. 스위칭 캐패시턴스를 줄이기 위하여 자주 사용되는 레지스터 전달 마이크로 오퍼레이션에 레지스터간의 직접적인 전달 구조를 적용하였다. 입력데이터의 상승예지 시간을 줄이기 위하여 분산 버퍼구조를 제안하였다. 또한 성능저하 없이 소비전력을 줄이기 위하여 파이프라인 구조에 적용된다. 본 논문에서는 CISC 명령어를 처리하기에 적합한 파이프라인이 설계되었다. 설계된마이크로콘트롤러는 전력소모를 20%정도 감소시켰다. 전력소모를 측정하기 위해서는 SYNOPSYS의 EPIC powermill과 현대 0.6um CMOS 파라메터를 적용하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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• pp.19-22
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• 2004

The resonant planar transformer, which had power capacity of 300 W, input voltage of 220 V, output voltage of 15 V, and switching frequency of 500 kHz, was designed and manufactured by using the planar core with large effective area and the flat copper lead frames for miniaturization and high efficiency of the switching mode power supply (SMPS). As well as, a resonant converter equipped with the above mentioned planar transformer was manufactured and electromagnetic characteristics were investigated. The numerical value of turns for 1st and 2nd winding were 12 and 2 respectively. The self inductance of 1st winding was 33.2 ${\mu}H$, very low leakage inductance of 1.27 ${\mu}H$, and the coupling factor of 0.98 were obtained at switching frequency of 300 kHz. The high efficiency of 88.21 % for the SMPS equipped with planar transformer was obtained at power capacity of 300 W.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.484-485
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• 2003

We report on the optimization of the fabrication process of hybrid sol-gel thin film deposition to produce low cost $1 {\times} 16$ splitters for optical communications. We learn that sol-gel film thickness is dependent upon the spinning speeds and viscosity of the sol-gel solutions and refractive index upon the dopant concentrations of Al and Zr in the sol solutions. We could find the optimized physical conditions to achieve the desired thickness of core and cladding layers. We will further carry out the fabrication and measurements of insertion loss, polarization dependent loss (PDL), etc. for the performance of fabricated splitter devices.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.140-142
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• 2005

SMPS의 손실에는 switching loss, conduction loss, core loss가 있다. 최근 SMPS에서는 switching loss를 줄여 효율을 높이고자 반도체 스위치 2개를 사용하는 공진형 구조가 증가하고 있다하지만 공진형 구조는 반도체 스위치에서 소비되는 conduction loss로 의해 기존의 컨버터에 비해 무부하시 전력 소모가 크다. 그러나 최근 시장은 무부하시 소비되는 대기전력의 규제가 이슈가 되고 있다. 본 논문에서는 active clamped flyback converter에서 무부하시 반도체 스위치의 conduction loss의 감소를 위해 Clamp 회로의 보조 스위치는 동작시키지 않고, flyback converter로만 동작하도록 설계하여 무부하시에는 기존의 flyback converter의 동작과 같이 도통 손실이 급속히 줄도록 하였다. 또한 스위칭 손실을 줄이기 위해 주 스위치의 동작 주파수를 감소시켜 SMPS의 무부하시의 소모를 감소시켰다. 70W급 SMPS의 제작과 실험을 통해 위의 방법을 증명하고자 한다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권8호
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• pp.358-363
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• 2005

This paper presents the reasonable design parameters of a switched reluctance motor to drive a hybrid electric vehicle by using the equivalent magnetic circuit method. The designed motor can be redesigned by using finite element analysis as a variation of the parameter for the purpose of improving performance. This paper shows that a flat-topped current of a phase can be made from a change of the lamination stack length for high average torque and a lower torque ripple. The change of current falling time as a variation of turn-off angle was shown by finite element analysis. The core loss and copper loss were described. The torque of the redesigned motor is suitable for low and high speed ranges to drive a HEV. which is verified by the speed-torque curve.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전력기술부문
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• pp.12-14
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• 2007

A voltage transformer (VT) is used to transform a high voltage into a low voltage as an input for a metering device or a protection relay. VTs use an iron core which maximizes the flux linkage. The primary current of the VT has non-fundamental components caused by the hysteresis characteristics of the iron core. It causes a voltage drop in the winding impedances resulting in the error of the VT. This paper describes a compensation algorithm for the VT. The proposed algorithm can compensate the secondary voltage of VT by calculating the primary current from the exciting current of the hysteresis loop in the voltage transformer. In this paper, the exciting branch was divided into a non-linear core loss resistor and a non-linear magnetizing inductor. The performance of the proposed algorithm was validated under various conditions using EMTP generated data. Test results show that the proposed compensation algorithm can improve the accuracy of the VT significantly.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.39-44
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• 2005

In HANARO, a multi-purpose research reactor of 30 MWth, the emergency water supply system consists essentially of an emergency water storage tank located in the level of about thirteen meter (13 m) above the reactor core, a three inch ('3\%') diameter water injection pipe line including injection valves from the tank to the reactor cooling inlet pipe and a test loop to do periodic system performance test. When the water level of the reactor pool comes down to the extremely low due to a loss of reactor pool water accident the emergency water stored in the tank should be fed to the core by the gravity force and at that time the design flow rate is eleven point four kilogram per second (11.4 kg/s). But it is impossible periodically to measure the injection flow rate under the emergency condition because the normal water level should be maintained during the reactor operation. This paper describes a flow network analysis to simulate the flow rate under the emergency condition. As results, it was confirmed through the analysis results that the calculated flow rate agrees with the design requirement under the emergency condition.

• 한국전기전자재료학회논문지
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• 제17권3호
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• pp.340-347
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• 2004

Ultra-small size, high-performance, solenoid-type RF chip inductors utilizing low-loss A1$_2$O$_3$ core materials were investigated. The dimensions of the RF chip inductors fabricated were 1.0mm${\times}$0.5mm${\times}$0.5mm and copper coils were used. The materials (96％ A1$_2$O$_3$) and shape (I-type) of the core, the diameters (40${\mu}{\textrm}{m}$) and position (middle) of the coil, and the lengths (0.35mm) of solenoid were determined by a high-frequency structure simulator (HFSS) to maximize the performance of the inductors. The high-frequency characteristics of the inductance (L) and quality-factor (Q) of the developed inductors were measured using a RF impedance/material analyzer (E4991A with E16197A test fixture). The developed inductors exhibit an inductance of 11 to 11.3nH and a qualify factor of 22.3 to 65.7 over the frequency ranges of 250 MHz to 1.7 GHz, and show results comparable to those measured for the inductors prepared by Coilcraft$^{TM}$. The simulated data described the high-frequency data of the L and Q of the fabricated inductors well.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1666-1669
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• 1996

To produce low loss amorphous molding cores which are used as choke cores in high efficiency electronic ballast for Metal Halide Lamp, the magnetic properties of amorphous molding cores were investigated with the various fabrication methods. The results are as follows : (1) The total weight of molding core gradually increased as molding time increases. (2) The magnetic properties($B_{10}$, $B_r$, $B_t/B_s$, $H_c$, $W_c$) of molding core drastically deteriorated. This is presumably due to the compressive stress imposed on amorphous core occurred during epoxy curing treatment. (3) Two step annealing process(curing+field annealing) was more or less effective to recover the damaged properties.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.803-810
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• 2022

The small modular liquid-metal fast reactor (SMFR) is an important component of advanced nuclear systems. SMFRs exhibit relatively low breeding capability and constraint space for control rod installation. Consequently, control rods are deeply inserted at beginning and are withdrawn gradually to compensate for large burnup reactivity loss in a long lifetime. This paper is committed to investigating the impact of control rod compensation operation on core neutronics characteristics. This paper presents a whole core fine depletion model of long lifetime SMFR using OpenMC and the influence of depletion chains is verified. Three control rod position schemes to simulate the compensation process are compared. The results show that the fine simulation of the control rod compensation process impacts significantly the fuel burnup distribution and absorber consumption. A control rod equivalent position scheme proposed in this work is an optimal option in the trade-off between computation time and accuracy. The control position is crucial for accurate power distribution and void feedback coefficients in SMFRs. The results in this paper also show that the pin level power distribution is important due to the heterogeneous distribution in SMFRs. The fuel burnup distribution at the end of core life impacts the worth of control rods.