• Title/Summary/Keyword: equivalent series resistance

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Property analysis of multi layer Organic Light Emitting Diodes using equivalent circuit models (등가 회로 모델을 이용한 다층 유기발광 소자의 특성 분석)

  • Park, Hyung-Jun;Kim, Hyun-Min;Yi, Jun-Sin;Nam, Eun-Kyoung;Jung, Dong-Geun
    • Proceedings of the KIEE Conference
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    • 2006.10a
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    • pp.119-120
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    • 2006
  • The impedance spectroscopy is one of the effective ways to understand the electrical properties of organic light emitting diodes. The frequency-dependant properties of small molecule based OLEDs have been studied. The equivalent circuit of single-layer device is composed of contact resistance ($R_c$), bulk resistance ($R_p$) and bulk capacitance ($C_p$). The equivalent circuit of double layer device is composed of two parallel circuits connected in series, each of which is a parallel resistor and a capacitor. We have fabricated a double layer device indium-rio-oxide (ITO, anode), N,NV -diphenyl- N,NV -bis(3-methylphenyI)-1,1V -diphenyl-4,4V-diamine (TPD, hole-transporting layer), tris-(8-hydroxyquinoline) aluminum (Alq3, emitting layer), and aluminum (AI, cathode) and two single layer devices ([TO/ Alq3/ AI, ITO/TPD/AI).

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Electric Circuits Modeling of Magnetoelectric Bulk Composites in Low Frequency (ME 소자의 저주파 등가회로 모델링)

  • Chung, Su-Tae;Ryu, Ji-Goo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.7
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    • pp.515-521
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    • 2013
  • Magnetoelectric(ME) bulk composites with PZT-PNN-PZN/$Fe_2O_4$ were prepared by using a conventional ceramic methods and investigated on the ME voltage vs frequency of ac magnetic fields. We made the electric equivalent circuits by using the Maxwell-Wagner model and simulated the frequency dependence of ME voltage in low frequency region. ME devices were described by a series of two equivalent circuits of piezoelectric and magnetic, which have the relaxation time ${\tau}$ due to the interaction between ME device and load resistor. Equivalent circuit of piezoelectric material is independent of frequency. However ferrite magnetic materials have Debye absorption and dipolar dispersion, whose equivalent circuit is a function of frequency. Therefore we suggest the resistance in the equivalent circuit is proportion to $1+{\omega}^2{\tau}^2$ and the capacitance is in inverse proportion to $1+{\omega}^2{\tau}^2$ in the magnetic materials.

Battery Equalization Method for Parallel-connected Cells Using Dynamic Resistance Technique

  • La, Phuong-Ha;Choi, Sung-Jin
    • Proceedings of the KIPE Conference
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    • 2018.11a
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    • pp.36-38
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    • 2018
  • As the battery capacity requirement increases, battery cells are connected in a parallel configuration. However, the sharing current of each battery cell becomes unequal due to the imbalance between cell's impedance which results the mismatched states of charge (SOC). The conventional fixed-resistance balancing methods have a limitation in battery equalization performance and system efficiency. This paper proposes a battery equalization method based on dynamic resistance technique, which can improve equalization performance and reduce the loss dissipation. Based on the SOC rate of parallel connected battery cells, the switches in the equalization circuit are controlled to change the equivalent series impedance of the parallel branch, which regulates the current flow to maximize SOC utilization. To verify the method, operations of 4 parallel-connected 18650 Li-ion battery cells with 3.7V-2.6Ah individually are simulated on Matlab/Simulink. The results show that the SOCs are balanced within 1% difference with less power dissipation over the conventional method.

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Effects of the Recycled Waste Rope Fibers on the Strength and Carbonation Resistance of Cementitious Composites (폐로프 재활용 섬유보강 시멘트 복합체의 탄산화가 강도에 미치는 영향)

  • Sanghwan Cho;Taek Hee Han;Min Ook Kim
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.4
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    • pp.407-415
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    • 2023
  • In this study, a carbonation test was conducted on cementitious composites reinforced with recycled waste rope fibers (W series) according to EN 12390-12 standards. The test results were compared to those of commercially available polypropylene fibers (P series). In the carbonation test, both the carbonation depth and area were significantly influenced by the water-to-cement ratio. Notably, the carbonation resistance performance of cementitious composites containing waste rope fibers surpassed that of commercially available PP fibers under equivalent conditions. Throughout the 250-day test period, the W series exhibited higher compressive strength values than the P series, while both series displayed a similar trend of strength increase during the same duration. During the initial stage, the W series exhibited flexural strength levels similar to those of the P series. However, in the later stages, the P series showed a higher mean flexural strength by 1.0 MPa.

Series-parallel resonant converter using a contactless power supply for the efficiency improvement (효율 개선을 위한 직${\cdot}$병렬 공진컨버터 적용 비접촉 전원)

  • Kong Y.S.;Lee H.K.;Kim E.S.;Cho J.G.;Kim J.M.
    • Proceedings of the KIPE Conference
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    • 2004.11a
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    • pp.45-48
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    • 2004
  • To improve the efficiency characteristics in the resonant converter using the contact-less power supply with the large air-gap and the long primary winding, this paper suggests the three-level series-parallel resonant converter(SPRC). The voltage gain characteristics of the proposed converter have the unit gain in a resonance frequency point of the series and parallel, and input voltage and current in the primary of SPRC are always In phase for the all equivalent load resistance because of the parallel resonant tank of the high impedance. The results are verified on the simulation based on the theoretical analysis and the 4kW experimental prototype.

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Physical-based Dye-sensitized Solar Cell Equivalent Circuit Modeling and Performance Analysis (물리 기반의 염료 감응형 태양전지 등가회로 모델링 및 성능 분석)

  • Wonbok Lee;Junhyeok Song;Hwijun Choi;Bonyong Gu;Jonghwan Lee
    • Journal of the Semiconductor & Display Technology
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    • v.22 no.3
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    • pp.67-72
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    • 2023
  • In this paper, a dye-sensitized solar cell (DSSC), one of the representative third-generation solar cells with eco-friendly materials and processes compared to other solar cells, was modeled using MATLAB/Simulink. The simulation was conducted by designating values of series resistance, parallel resistance, light absorption coefficient, and thin film electrode thickness, which are directly related to the efficiency of dye-sensitized solar cells, as arbitrary experimental values. In order to analyze the performance of dye-sensitized solar cells, the optimal value among each parameter experimental value related to efficiency was found using formulas for fill factor (FF) and conversion efficiency.

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Life Estimation of DC Link Electroytic Capacitors (직류 링크 전해 커패시터의 수명 추정)

  • 이동춘
    • Proceedings of the KIPE Conference
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    • 2000.07a
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    • pp.57-60
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    • 2000
  • An aluminum electrolytic capacitor is used in DC Link of ac motor drive system. In this case it usually has the shortest lifetime in the system and then determines the system lifetime. Therefore life estimation of the electrolytic capacitor is needed for maintenance of th circuit. In this paper a method for life estimation is presented with a ESR(equivalent series resistance) model and a heat transfer model of capacitor that can be used to estimate operating temperature it is investigated through a simple example using ESR and heat transfer.

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A Study on the Stacked type Film Chip Capacitor (적층형 필름 Chip Capacitor 개발)

  • 송호근;박상식;연강흠;김성호
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1991.10a
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    • pp.73-78
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    • 1991
  • In this study of stacked type film chip capacitor, the important parameters are heat-treated temperature, pressure and time. We measured the temperature dependence of dielectric properties and dissipation factor and the frequency dependence of dielectric properties, dissipation factor, ESR(Equivalent Series Resistance) and impedance in stacked type film capacitor. As a result, the best conditions of heat-treated temperature, pressure and time were proved to be 130$^{\circ}C$, 10kg/$\textrm{cm}^2$ and 3hrs, respectively.

Life Estimation of Electrolytic Capacitors in Inverters (인버터용 전해커페시터의 수명 추정)

  • Lee, Dong-Choon
    • Proceedings of the KIEE Conference
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    • 2000.11a
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    • pp.243-245
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    • 2000
  • In general, aluminum electrolytic capacitors are used in the DC link of PWM inverters fur ac motor drives. The capacitor usually has the shortest lifetime in the system and then determines the lifetime of the inverter system. In this paper, a method of capacitor lifetime estimation is proposed by using an ESR(equivalent series resistance) model and a heat transfer model of capacitor, from which internal operating temperature is estimated. Then, the lifetime is predicted by Arrhenius's equation. A practical example is presented.

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The modeling method of ignitors for HID lamps (HID 램프용 점화기의 모델링 기법)

  • Park, Chong-Yeun;Lim, Byoung-Noh;Jang, Mok-Soon
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1104-1105
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    • 2007
  • 본 논문은 고압방전램프용 안정기의 점화기 4종류를 ESR(Equivalent Series Resistance)를 고려하여 등가모델링 하였다. 전자식 안정기의 구동식에 따른 풀 브리지 방식의 점화기 2종류와 하프 브리지 방식의 1종류 마지막으로 자기식 안정기의 점화기를 모델링하고 타당성을 증명하기 위해 실험을 통하여 입증하였다.

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