• Title, Summary, Keyword: capacitor

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The Carrier-based PWM Method for Voltage Balance of Flying Capacitor Multi-bevel Inverter (플라잉 커패시터 멀티-레벨 인버터의 커패시터 전압 균형을 위한 캐리어 비교방식의 펄스폭변조기법)

  • 이상길;강대욱;이요한;현동석
    • The Transactions of the Korean Institute of Power Electronics
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    • v.7 no.1
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    • pp.65-73
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    • 2002
  • This paper proposes a new carrier-based PWM method to solve the most serious problem of flying capacitor multi-level inverter that is the unbalance of capacitor voltages. The voltage unbalance occurs due to the difference of each capacitor's charging and discharging time applied to Flying Capacitor Inverter. New solution controls the variation of capacitor voltages into the mean '0'during some period by means of new carriers using the leg voltage redundancy in the flying capacitor inverter. The solution can be easily expanded to the multi-level inverter. The leg voltage redundancy in the new method makes the switching loss of device equals to the conduction loss of device. This paper will examine the unbalance of capacitor voltage and the conventional theory of self-balance using Phase-shifted carrier. And then the new method that is suitable to the flying capacitor inverter will be explained.

A High Tunable Capacitor Embedding Its Electrodes in Tunable Thin Film Dielectrics (가변형 박막 유전체에 전극을 임베디드 시킨 고가 변형 커패시터)

  • Lee Young-Chul;Hong Young-Pyo;Ko Kyung-Hyun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.9
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    • pp.860-865
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    • 2006
  • In this paper, a novel tunable inter-digital capacitor using dielectric tunable $Bi_2O_3-ZnO-Nb_2O_5(BZN)$ pyrochlore thin films is proposed. In order to improve the tunability and reduce DC bias voltage using the fringing electric field, the electrodes of the inter-digital capacitor are embedded in the thin film. Designed results using a 2.5 D simulator show that the tunability of the proposed inter-digital capacitor improves by 10 %, compared to the conventional inter-digital capacitor. The proposed IDC, which is based on the simulation results, was fabricated, using the BZN thin film deposited by a reactive RF magnetron sputtering on the on the silicon substrate. The fabricated inter-digital capacitor shows the maximum tunability of 50 % at 5.8 GHz and 18 V DC applied.

Study of Back-Up Electric Power Source as a Role for Instant Power Industry Safety by Super Capacitor (순간 정전시 산업안전용 보조전원 역할의 Super Capacitor에 관한 연구)

  • 김상길;김종철;허진우;김경민;이용욱;강안수
    • Proceedings of the Safety Management and Science Conference
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    • pp.345-354
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    • 1999
  • A new type of capacitor named "Super Capacitor" has been developed, in which the properties of electric double layer formed at the interface of activated carbon electrode- liquid organic electrolyte is applied. This capacitor is small In size, light in weight, wide In temperature range(-25~$70^{\circ}C$), large in charge-discharge capability and good in voltage preservation. And this super capacitor is applied as a power back-up for electricity failure in volatile memory devices etc., a power source for a short time and a power source for operating actuators. At present the development of high power back-up types of the capacitor system and improvement of their characteristics are being actively conducted in order to find wider applications.lications.

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EFFICIENT DESIGN OF CAPACITOR DISCHARGE IMPULSE MAGNETIZER SYSTEM FOR 8-POLE MAGNET

  • Kim, Pill-Soo;Kim, Yong;Baek, Soo-Hyun
    • Journal of the Korean Magnetics Society
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    • v.5 no.5
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    • pp.828-832
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    • 1995
  • This paper describes the efficient design, analysis method and experimental verification of capacitor discharge impulse magnetizer system. A capacitor discharge magnetizer system is used to produce a high current impulse of short duration in this magnetizing fixture. The parasitic resistance and parasitic inductance of the capacitor discharge impulse magnetizer system have been estimated using known air-core test coil. Finite element analysis (using MAXWELL 2-D field simulator) and magnetizing circuit analysis (using SPICE) are also used as part of the design and analysis process of the capacitor discharge impulse magnetizer system. Application study for a magnetizing fixture design is shown. 8-pole magnetizing fixture has been designed and analyzed using finite element analysis. The fixture design for 8-pole magnet are presented along with the experimental results. The experimental results have been achieved using a high-voltage, high-energy capacitor discharge impulse magnetizer and 8-pole iron core fixtures (charging voltage : 2000[V], capacitor bank : 4000[$\mu\textrm{F}$]).

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Optimization of Capacitor Threshold VT Implantation for Planar P-MOS DRAM Cell (평면구조 P-MOS DRAM 셀의 커패시터 VT 이온주입의 최적화)

  • Chang Sung-Keun;Kim Youn-Jang
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.2
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    • pp.126-129
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    • 2006
  • We investigated an optimized condition of the capacitor threshold voltage implantation(capacitor $V_T$ Implant) in planar P-MOS DRAM Cell. Several samples with different condition of the capacitor $V_T$ Implant were prepared. It appeared that for the capacitor $V_T$ Implant of $BF_2\;2.0{\times}l0^{13}\;cm^{-2}$ 15 KeV, refresh time is three times larger than that of the sample, in which capacitor $V_T$ Implant is in $BF_2\;1.0{\times}l0^{13}\;cm^{-2}$ 15 KeV. Raphael simulation revealed that the lowed maximum electric field and lowed minimum depletion capacitance ($C_{MIN}$) under the capacitor resulted in well refresh characteristics.

Harmonic Analysis of Reactor and Capacitor in Single-tuned Harmonic Filter Application

  • Kim, Jong-Gyeum;Park, Young-Jeen;Lee, Dong-Ju
    • Journal of Electrical Engineering and Technology
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    • v.6 no.2
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    • pp.239-244
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    • 2011
  • Industrial power distribution system includes many kinds of non-linear loads, which produce the harmonics during energy conversion transition. The single-tuned passive filter is widely used to absorb the harmonics and attenuate its undesirable effect in the distribution system. However, the passive filter might be severely stressed, and sometimes even damaged, due to the absorption of harmonics. There is voltage rise on the capacitor when the single-turned harmonic filter is applied. When the capacitor voltage rose above the allowable limit, the expected life of the capacitor will considerably deteriorate. On the other hand, the reactor can experience the spike voltage even if the voltage and current of the capacitor are within the allowable limit, and this accumulated voltage stress of the reactor causes its premature fault. In this paper, we analyzed and compared the harmonic voltage and current of the reactor and capacitor in a single-tuned harmonic filter through the EMTP software and verified them with the experimental results.

A Simple ESR Measurement Method for DC Bus Capacitor Using DC/DC Converter (DC/DC 컨버터를 이용한 DC Bus 커패시터의 간단한 ESR 측정 기법)

  • Shon, Jin-Geun;Kim, Jin-Sik
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.4
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    • pp.372-376
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    • 2010
  • Electrolytic capacitors have been widely used in power electronics system because of the features of large capacitance, small size, high-voltage, and low-cost. Electrolytic capacitors, which is most of the time affected by aging effect, plays a very important role for the power electronics system quality and reliability. Therefore it is important to estimate the parameter of an electrolytic capacitor to predict the failure. The estimation of the equivalent series resistance(ESR) is important parameter in life condition monitoring of electrolytic capacitor. This paper proposes a simple technique to measure the ESR of an electrolytic capacitor. This method uses a switching DC/DC boost converter to measure the DC Bus capacitor ESR of power converter. Main advantage of the proposed method is very simple in technique, consumes very little time and requires only simple instruments. Simulation results are shown to verify the performance of the proposed method.

A Study on the Characteristic of Capacitor by Asymmetrical Voltage Unbalance (비대칭 전압 불평형에 의한 커패시터 동작 특성)

  • Kim, Jong-Gyeum;Park, Young-Jeen
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.1
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    • pp.18-23
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    • 2010
  • As the increasing of Non-linear load, we have been growing interest for the harmonics. Harmonics has been focused on the current component rather than voltages. Voltage harmonics can be mainly generated at the PCC with non-linear load and act on voltage unbalance. Voltage harmonics can be enlarged at the capacitor with low impedance as frequency increases. Capacitor is basically used for the power-factor compensation and sometimes as the passive filter. Small voltage of low-order acts on quite a few at the capacitor by the current increase. Capacitor has easily fall under by harmonic components. In this paper, we measured the magnitude and phase angle of asymmetrical voltage with harmonics components at the PCC and calculated with the same condition. we concluded that voltage harmonics of higher order increase each current component but have a little effect on capacitor rating.

Characteristics Analysis of Capacitor and Reactor for Harmonic Filter (고조파 필터용 커패시터와 리액터의 특성 해석)

  • Kim, Jong-Gyeum;Park, Young-Jeen;Lee, Eun-Woong
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.1
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    • pp.1-8
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    • 2009
  • Recently, application of non-linear load is gradually increased. Non-linear load produces harmonic components of current during the energy conversion transition. Passive filter is used for reducing of harmonics in the user power systems. This filter, which is composed of capacitor and reactor, frequently get out of order by electrical stress. There are voltage and current increase when capacitor and reactor are applied in the user's filter systems. If increased voltage and current is above stipulated values, they have severely an influences on the life of capacitor and reactor. This paper describes that the voltage and current of capacitor used for filter is within the limits of allowable values, but reactor is beyond the limits and reveals spike voltage. Therefore this phenomenon brings about premature fault of reactor and capacitor.

Series Voltage Compensation Systems for Voltage Sag by Using an Environmentally Friendly Ultra-capacitor (친환경 Ultra-capacitor에 의한 순시전압강하의 직렬전압보상 시스템)

  • Shon, Jin-Geun;Jeon, Hee-Jong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.4
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    • pp.763-769
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    • 2009
  • A series voltage compensation(SVC) system is a power-electronics controller that can protect sensitive loads from disturbance in the supply system. Especially, voltage sags are considered the dominant disturbances affecting the power quality. This paper dealt with a system of off-line type voltage sag compensation by using a bi-directional DC/DC converter of environmentally friendly ultra-capacitor. This capacitor is attached to the DC link of SVC through the high-efficiency DC/DC converter in order to compensate the DC link voltage drop during short-term power interruption as voltage sags. Therefore, in this paper, a DC/DC converter to control high-efficiency energy of ultra-capacitor and voltage sag detection algorithm of off-line type SVC systems are newly introduced. According to the results of experimental of prototype system, it is verified that the proposed system has effectiveness of voltage sag compensation using an ultra-capacitor.