• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1424-1425
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• 2007

In this paper approves AC high voltage by experimental GIS(Gas Insulated Switchgear) chamber and AC 300[kV] power source to study breakdown characteristics by pressure(P) change and change of electrode distance(d) at AC high voltage of Imitation Air(I-Air, $N_2$ : $O_2$ = 79[%] : 21[%]) to alternate $SF_6$ and achieved research. Gave P change of I-Air to study I-Air's breakdown characteristics using niform fields(Sphere-Sphere electrode) and non-uniform fields(Needle-Plane electrode) and studied relations breakdown voltage ($V_B$) by each P different d.

• 한국전기전자재료학회논문지
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• 제20권5호
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• pp.403-409
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• 2007

In this paper, effects of the trench angle($\theta$) on the breakdown voltage according to the process parameters of p-base region and doping concentrations of n-drift region in a Trench Gate IGBT (TIGBT) device were analyzed by computer simulation. Processes parameters used by variables are diffusion temperature, implant dose of p-base region and doping concentration of n-drift region, and aspects of breakdown voltage change with change of each parameter were examined. As diffusion temperature of the p-base region increases, depth of the p-base region increases and effect of the diffusion temperature on the breakdown voltage is very low in the case of small trench angle($45\;^{\circ}$) but that is increases 134.8 % in the case of high trench angle($90\;^{\circ}$). Moreover, as implant dose of the p-base region increases, doping concentration of the p-base region increases and effect of the implant dose on the breakdown voltage is very low in the case of small trench angle($45\;^{\circ}$) but that is increases 232.1 % in the case of high trench angle($90\;^{\circ}$). These phenomenons is why electric field concentrated in the trench is distributed to the p-base region as the diffusion temperature and implant dose of the p-base increase. However, effect of the doping concentration variation in the n-drift region on the breakdown voltage varies just 9.3 % as trench angle increases from $45\;^{\circ}$ to $90\;^{\circ}$. This is why magnitude of electric field concentrated in the trench changes, but direction of that doesn't change. In this paper, respective reasons were analyzed through the electric field concentration analysis by computer simulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.195-198
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• 2000

In this paper the insulation characteristics test results of 25 low-voltage induction motors($3\phi$, 5HP, 380V) are presented. Five different types of insulation techniques are applied to 25 motors. The maximum partial discharge (PD) magnitude ($\textrm{Q}_{m}$) discharge inception voltage (DIV) dissipation factor tip-up ($\Delta$tan$\delta$) and rate of change in AC current($\Delta$I) are measured by PD and AC current tests. Also the insulation breakdown tests by high voltage pulse are performed and the corresponding breakdown voltage are obtained.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1426-1430
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• 2009

AC AT feeding method consists return circuits of electric train inserting in parallel between trolly line and feeding line and connecting neutral line to rail and FPW. Due to increasing electric load at feeding system, collecting voltage of train and end voltage are going down. So to increase voltage between trolly line and rail, the usefulness of new autotransformer are considered which variation of short impedance and change of line voltage is simulated with modified winding ratio of autotransformer from 1:1 to variable tab.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.197-200
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• 2001

This paper presents a PWM buck AC-AC converter with instantaneous compensation for input voltage sag and surge. The presented converter use commercial IGBT modules and its output voltage is regulated so as to remain constant AC output voltage. The feedforward control technique is also proposed to establish instantaneous duty level change whereby stable output voltage will be retained. This paper show the characteristics and control algorithm of the converter through various PSPICE simulations.

• 한국방사선학회논문지
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• 제13권5호
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• pp.705-711
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• 2019

현재 최신 장비의 두부 CT검사에서 파라메타의 변화와 선량변화에 대한 연구가 부족하고 특히 노이즈, 균일도 해석 및 선량변화에 대한 연구가 부족하다고 생각된다. 따라서 높은 사양 두부 CT 사용 시 노출 파라메타 중 관전압, 슬라이스 두께, 피치변화에 대해 분석하여 이때 발생하는 현상에 대해서 연구하고자 하였다. 실험을 통해서 균일도는 고관전압과 두꺼운 슬라이스 선택 및 최저 피치를 사용할 때 균일도가 좋음을 알 수 있었다. 모두 조합한 결과 균일도가 가장 조건은 140 kVp, 10 mm, pitch 0.5로 나타났다. 노이즈는 관전압과 슬라이스 두께를 높이면 피치에 관계없이 개선되는 것을 알 수 있었고, 선량은 관전압과 피치의 증가에 따라 선형적으로 증가하는 것으로 나타났다. 따라서 본 연구결과는 고 사양의 두부 CT 사용에서 참고자료가 될 것이다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권11호
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• pp.503-507
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• 2005

Both ratio error and phase angle error in voltage transformer(VT) depend on values of VT burden used. Thus, precise measurement of burden is very important for the evaluation of VT. A method of evaluation for VT burden has been developed by employing the portable decade resistor, with AC-DC resistance difference less than 10-3. The burden value(value and power factor) can be obtained by conductance and susceptance, obtained by measuring the change of ratio error and phase angle error caused by the resistance change of decade resistor. The burden value and power factor obtained by the method are consistent with those obtained using power analyzer within corresponding uncertainties.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.184.2-184.2
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• 2010

This study performs modelling and simulation of permanent magnetic synchronous generator wind turbine by using Matlab & Simulink. In simulation, change of wind velocity, change of load, and voltage decrease of infinite bus are performed. Through such simulation, different with wiring system that there is only existing load, this study can confirm problems and voltage changing characteristics, which can occur in distributed electric power that load and electric power is mixed and operated, especially, in interconnecting with wind power generation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.148-148
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• 2010

Measuring the a-IGZO TFTs with various temperatures was found to induce a threshold voltage shift and a change of the subthreshold gate voltage swing. Characteristic change is dependant on a material of the substrate at the temperature from $20^{\circ}C$ to $100^{\circ}C$. The threshold voltage was shifted to the left from -2.7V to -61V on SiO2/galss. But, as the temperature increases form $20^{\circ}C$ to $100^{\circ}C$. the threshold voltage was shifted to the right from 0.85V to 2.45V.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.877-880
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• 1989

Described is a DC voltage regulator of new type where an optical fiber is used as a sense line to transmit the PFM signal, which represents the load voltage and its change, from the load to the controller so as to make the equivalent sense-line length short. The prototype version provides a load voltage change rate of 2.3% over the current range of 0A to 5A at 15V DC, with an output impedance of 0.06ohm.