• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.222-225
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• 2003

In this paper the performance of the high speed circuit breaker with fault current detector is described. The operating mechanism of circuit breaker in use is a magnetic actuator and a fault current detector is based on the DSP and A/D converter. The results show that 3-cycle is enough to interrupt the fault current and the more speed up performance is expected with on-going project.

• 약학회지
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• 제37권1호
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• pp.76-83
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• 1993

The changes in discharge current, emission and/or oscillation frequency of the electric oscillation of a glow discharge are the potential sensitive measure of the concentration of an impurity in the argon plasma supporting gas. A single jet enhanced glow discharge has been interfaced with the gas chromatograph via 1/8" O.D. tube with a heating pad to study the changes in discharge current. To investigate the optimum operating conditions of the glow discharge system as detector for gas chromatography, pressure, gas flow rate, discharge current, distance between the anode and the cathode have been studied.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1593-1599
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• 2017

This paper presents a multi-channel light-emitting diode (LED) driver IC with a current-mode current regulator. The proposed current regulator replaces resistors for current sensing with a sequentially controlled single current sensor and a single regulation loop for sensing and regulating all LED channel currents. This minimizes the current mismatch among the LED channels and increases voltage headroom or, equivalently, power efficiency. The proposed LED driver IC was fabricated in a $0.35-{\mu}m$ BCD 60-V high voltage process, and the chip area is $1.06mm^2$. The measured maximum power efficiency is 93.4 % from a 12-V input, and the inter-channel current error is smaller than as low as ${\pm}1.3%$ in overall operating region.

• 한국정보전자통신기술학회논문지
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• 제3권4호
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• pp.35-42
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• 2010

본 논문은 기존 SELinux를 포함한 리눅스 보안 운영체제와 보안 모듈에 관한 선행 연구 분석을 통해 사용자 식별 인증, 주체 객체의 보안 권한 상속, 참조 모니터와 MAC 등급 처리, DB를 이용한 실시간 감사 추적이 적용된 리눅스 접근제어 보안 모듈을 다음과 같이 제안하였다. 첫째, 사용자 인증 시 접속 허용 IP를 판별하고 보안등급과 범주를 입력하게 하여 불법 침입자가 superuser(root) 권한을 획득하였다 하더라도 시스템 파괴가 불가능 하도록 설계 하였다. 둘째, 주체 및 객체의 보안 속성 상속을 통하여 주체가 보안이 설정된 객체에 접근할 때, 설정되어 있는 주체의 보안 정보와 객체에 설정되어 있는 보안 정보를 비교함으로써 접근 제어가 이루어지도록 하였다. 셋째, 커널상에서 현재 발생하는 모든 사건에 대해 참조모니터의 감사를 진행하며, 악의적인 목적으로 여러 객체에 접근하는 것을 사전에 차단하도록 하였다. 넷째, DB를 이용한 실시간 보안 감사 추적 시스템을 통해 각 행위와 관련된 보안 감사 자료는 보안 관리자에게 실시간으로 제공되기 때문에 긴급 상황이나 문제 발생 시 즉각 대처할 수 있도록 설계하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.780_781
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• 2009

This paper proposes efficiency optimization control of IPMSM drive using hybrid intelligent controller(HIC). The design of the speed controller based on fuzzy-neural network that is implemented using fuzzy control and neural network. The design of the current based on adaptive fuzzy control using model reference and the estimation of the speed based on neural network using ANN controller. In order to maximize the efficiency in such applications, this paper proposes the optimal control method of the armature current. The optimal current can be decided according to the operating speed and the load conditions. This paper proposes speed control of IPMSM using ALM-FNN, current control of model reference adaptive fuzzy control(MTC) and estimation of speed using ANN controller. The proposed control algorithm is applied to IPMSM drive system controlled HIC, the operating characteristics controlled by efficiency optimization control are examined in detail.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.776_777
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• 2009

Optimal efficiency control of synchronous reluctance motor(SynRM) is very important in the sense of energy saving and conservation of natural environment because the efficiency of the SynRM is generally lower than that of other types of AC motors. This paper is proposed a novel efficiency optimization control of SynRM considering iron loss using neural network(NN). The optimal current ratio between torque current and exciting current is analytically derived to drive SynRM at maximum efficiency. This paper is proposed an efficiency optimization control for the SynRM which minimizes the copper and iron losses. The design of the speed controller based on adaptive learning mechanism fuzzy-neural networks(ALM-FNN) controller that is implemented using fuzzy control and neural networks. The objective of the efficiency optimization control is to seek a combination of d and q-axis current components, which provides minimum losses at a certain operating point in steady state. The control performance of the proposed controller is evaluated by analysis for various operating conditions. Analysis results are presented to show the validity of the proposed algorithm.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.357-360
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• 2009

The present study focused on the segmented cell which has the similar performance to unaltered (not segmented) cell in real operating condition. Many literatures have been made the segmented cell to observe the behavior of local current density distribution in the single cell. However, it has been lack of scheme to segment the cell in that the detailed interpretation of segmenting in analytic point of view was insufficient. Hence, the basic idea of segmenting was introduced to determine the component to be segmented in anode side of unit cell. The electrical contact/bulk resistance was measured by using four wire/probe method through each part of cell components including MEA, GDL, Bipolar Plate and Current Collector. Electron transport mechanism was predicted by comparing resistance values which were obtained from the experiment. As a result, this offered a great benefit to segment the cell efficiently. With this method further experiments would be conducted in research areas which require current density distribution at the same operating condition as unaltered cell.

• ETRI Journal
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• 제38권2호
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• pp.244-251
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• 2016

In this paper, we investigate the electrical characteristics of two trench-gate-type super-barrier rectifiers (TSBRs) under different p-body implantation conditions (low and high). Also, design considerations for the TSBRs are discussed in this paper. The TSBRs' electrical properties depend strongly on their respective p-body implantation conditions. In the case of the TSBR with a low p-body implantation condition, it exhibits MOSFET-like properties, such as a low forward voltage ($V_F$) drop, high reverse leakage current, and a low peak reverse recovery current owing to a majority carrier operation. However, in the case of the TSBR with a high p-body implantation condition, it exhibits pn junction diode.like properties, such as a high $V_F$, low reverse leakage current, and high peak reverse recovery current owing to a minority carrier operation. As a result, the TSBR with a low p-body implantation condition is capable of operating as a MOSFET, and the TSBR with a high p-body implantation condition is capable of operating as either a pn junction diode or a MOSFET, but not both at the same time.

• 대한기계학회논문집
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• 제18권10호
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• pp.2706-2711
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• 1994

In this work, an experimental type of torque converter has been constructed and its characteristics have been evaluated by adapting an electrorheological fluid(ERF) as an operating medium. The device was designed by using the equations which were proposed by Carlson et al. The correlation between the rheological behaviour of an ERF and mechanical parameters of the clutch has been investigated. The torque generated by an ERF in this device is sum of one due to the yield strength by polarizing dispersed particles in dielectric oil and one due to the viscous drag. The experimental results are presented in terms of torque and current density as a function of rotational speed at various electric field strength applied. Experimental results showed that the measured torque was rapidly increased with the increase of the electric field, generally being proportional to the rotational speed of the motor. The measured current was shown to be increased with the increased electric field. Also, the current was decreased with the increase of increased with the increased electric field. Also, the current was decreased with the increase of the rotational speed of the motor and reached plateau region after f = 5 Hz.

• 전력전자학회논문지
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• 제7권5호
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• pp.405-412
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• 2002

전류원 브릿지 회로방식은 전압원 회로방식에 비해 스위치 차단 시 발생하는 전압 스파이크에 연루되는 에너지가 커 고효율로 동작하는 무손실 스너버가 필수적인데, 이 스너버는 그 동작원리가 복잡하고 동작조건이 바뀜에 따라 성능의 변동이 심하여 설계가 어려운 문제가 있다. 본 논문에서는 0.5 이상의 시비율로 동작하는 전류원 하프-브릿지 컨버터를 위한 무손실 스너버의 동작을 완전히 분석하고 설계사항에 대해 고찰한 뒤 실험을 통해 검증한다