• 조명전기설비학회논문지
• /
• 제17권6호
• /
• pp.95-104
• /
• 2003

전기 철도계통은 기존 전력계통과 달리 단상, 대용량 부하로 필연적으로 전압강하, 전압불평형 및 고조파 왜곡 등의 전력품질의 문제가 발생한다. 이러한 문제점 중 상시전압강하는 전력품질의 가중 중요한 요소로서 SVC(Static Var Compensator) 또는 STACOM(Static Compensator)를 설치하여 전압강하를 보상하는 연구가 수행되었다. 또한 순시전압강하는 고속으로 운전중인 철도차량의 제어 및 안전에 상당한 영향을 미칠것으로 예상된다. 따라서 본 논문에서는 AT(Auto Transformer)급전계통에 적용되는 순간전압강하 보상장치에 관한 연구를 수행하였다. 순간전압강하에 의한 철도차량의 과도해석을 위해 전원, 철도급전변압기, AT, 철도선로 및 철도 차량부하를 모델링 하였다. 또한 순간전압강하 발생시 철도차량부하의 과도특성을 분석하였고 이를 보상하기위한 순간전압강하 보상장치 (DVR:Dynamic Voltage Restorer)를 제안하였다. 순간전압강하 보상 시뮬레이션 결과, 순간전압강하 보상장치의 철도급전계통의 적용은 상당히 유용함을 알수있었다.

• 전기학회논문지
• /
• 제67권1호
• /
• pp.137-141
• /
• 2018

The voltage drop is important in electric railway for feeding a huge power of train on fixed feeding area. Nowadays it is tried to operate a high speed trains on conventional lines and there is problem on the voltage drop too. It is simulated on the conditions increased the turn ratio of trolley, installed autotransformer neutral line with variable taps. In result, it is compensated the voltage drop between ATs and better on last AT, not on the position of AT. And it is decreased a return current and neutral current of AT because of unbalance between trolley and feeder. It should be studied faster and more controllable the solid state switchs instead of the mechanical one in order to utilize this system.

• Nuclear Engineering and Technology
• /
• 제49권1호
• /
• pp.209-215
• /
• 2017

Fast neutron irradiation was used to improve the switching speed of a 600-V nonpunch-through insulated gate bipolar transistor. Fast neutron irradiation was carried out at 30-MeV energy in doses of $1{\times}10^8n/cm^2$, $1{\times}10^9n/cm^2$, $1{\times}10^{10}n/cm^2$, and $1{\times}10^{11}n/cm^2$. Electrical characteristics such as current-voltage, forward on-state voltage drop, and switching speed of the device were analyzed and compared with those prior to irradiation. The on-state voltage drop of the initial devices prior to irradiation was 2.08 V, which increased to 2.10 V, 2.20 V, 2.3 V, and 2.4 V, respectively, depending on the irradiation dose. This effect arises because of the lattice defects generated by the fast neutrons. In particular, the turnoff delay time was reduced to 92 nanoseconds, 45% of that prior to irradiation, which means there is a substantial improvement in the switching speed of the device.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 C
• /
• pp.1559-1561
• /
• 2003

In northeast Asia, there will be several important HVDC transmission lines to be established in Korea and China for perspective electric network market. 5500V 4-inches High voltage thyristor can be used in the DC transmission and distribution of electric power system. In this application, many thyristors are connected in series for each thyristor valves. Therefore, the required low reverse-recovery charge QRR and low on-state voltage drop $V_{TM}$ for such thyristor is necessary to this application. In our work, the on-state and off-state voltage performance was simulated by commercial simulation software.

• 한국안전학회지
• /
• 제29권2호
• /
• pp.12-17
• /
• 2014

This paper is aimed to analyze the characteristics of simultaneous voltage, current and temperature signals for poor connection on electrical connector. In order to attain this purpose, detected were the current and voltage signals on electric wire with series arc, named arc signals, and also monitored were the changes of RMS, instantaneous value of waveform in time domain and temperature value with video. Two states are made normal state over $5kgf{\cdot}cm$ and poor connections state below $0.5kgf{\cdot}cm$ by screw gage. In the voltage signal case, the voltage drop was increased with which the current was increased. In the current signal case, poor connections at the time interval 1~4A all showed "shoulder", as distinct difference from the normal state shown waveform pattern. In the temperature signal case, poor connections are twice at 1A and five times at 4A in the normal state. The temperature continues insulation of electrical wiring and connector can be carbonized. The results of this study will be effectively used in developing the preventive devices and system for electric fire by poor connections.

• Journal of international Conference on Electrical Machines and Systems
• /
• 제3권3호
• /
• pp.354-361
• /
• 2014

The Unified Power Flow Controller (UPFC) can flexibly manage power flow and maintain line voltage. The UPFC consists of two inverters in parallel side and series side. In parallel side, the reactive power can be compensated to improve the power factor. In series side, the voltage drop can be compensated to maintain proper line voltage. It is necessary for the operation in both sides to output the current and the voltage quickly and accurately. As the method for the UPFC control, the deadbeat control with state observer is applied. The deadbeat control is able to realize a quick response of the current and voltage control for only a sampling period compared with the general PI control. A principle and simulation results are presented in this paper.

• ETRI Journal
• /
• 제39권3호
• /
• pp.373-382
• /
• 2017

A new internally compensated low drop-out voltage regulator based on the cascoded flipped voltage follower is presented in this paper. Adaptive biasing current and fast charging/discharging paths have been added to rapidly charge and discharge the parasitic capacitance of the pass transistor gate, thus improving the transient response. The proposed regulator was designed with standard 65-nm CMOS technology. Measurements show load and line regulations of $433.80{\mu}V/mA$ and 5.61 mV/V, respectively. Furthermore, the output voltage spikes are kept under 76 mV for 0.1 mA to 100 mA load variations and 0.9 V to 1.2 V line variations with rise and fall times of $1{\mu}s$. The total current consumption is $17.88{\mu}V/mA$ (for a 0.9 V supply voltage).

• 한국전기전자재료학회논문지
• /
• 제28권8호
• /
• pp.496-500
• /
• 2015

This paper was proposed the theoretical research and optimal design 3000V super junction NPT IGBT for using electrical automotive and power conversion. Because super junction IGBT was showed ultra low on resistance, it was structure that can improve the thermal characteristics of conventional NPT IGBT. The electrical characteristics of super junction NPT IGBT were 2.52 V of on state voltage drop, 4.33 V of threshold voltage and 2,846 V breakdown voltage. We did not obtaing 3,000 V breakdown voltage but we will obtain 3,000 V breakdown voltage through improving p pillar layer. If we are carried this research, This device will be used electrical automotive, power conversiton and high speed train.

• 한국전기전자재료학회논문지
• /
• 제30권4호
• /
• pp.210-213
• /
• 2017

In this paper, we analyzed the structural design and electrical characteristics of a 3.3 kV super junction FS IGBT as a next generation power device. The device parameters were extracted by design and process simulation. To obtain optimal breakdown voltage, we researched the breakdown characteristics. Initially, we confirmed that the breakdown voltage decreased as trench depth increased. We analyzed the breakdown voltage according to p pillar dose. As a result of the experiment, we confirmed that the breakdown voltage increased as p pillar dose increased. To obtain more than 3.3 kV, the p pillar dose was $5{\times}10^{13}cm^{-2}$, and the epi layer resistance was $140{\Omega}$. We extracted design and process parameters considering the on state voltage drop.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.74-75
• /
• 2008

TIGBT has some merits which are lower on-state voltage drop and smaller cell pitch, but also has a defect which is relatively lower breakdown voltage in comparison with planar IGBT. This lower breakdown voltage is due to the electric field which is concentrated on beneath the vertical gate. Therefore in this paper, new trench IGBT structure is proposed to improve breakdown voltage In the new proposed structure, a narrow oxide beneath the trench gate edge where the electric field is concentrated is extended into rectangular shape to decrease the electric field. As a result, breakdown voltage is improved to 23%.