• Title/Summary/Keyword: equivalent series resistance

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Electrical Conduction Mechanism and Equivalent Circuit Analysis in $Alq_3$ based Organic Light Emitting Diode ($Alq_3$에 기초한 유기 발광 소자에서 전기전도특성과 등가회로분석)

  • Chung, Dong-Hoe;Shin, Cheol-Gi;Lee, Dong-Gyu;Lee, Joon-Ung;Lee, Suk-Jae;Lee, Won-Jae;Jang, Kyung-Wook;Kim, Tae-Wan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.103-106
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    • 2004
  • We have studied a conduction mechanism and equivalent circuit analysis in $Alq_3$ based Organic Light Emitting Diode. The conduction mechanism in organic light emitting diode can be classified into three regions; ohmic region, space-charge-limited current (SCLC) region and trap-charge-limited current (TCLC) region depending on the region of applied voltage. Equivalent circuit model of organic light emitting diode can be established using a parallel combination of resistance $R_p$ and capacitance $C_p$ with a small series resistance $R_s$.

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A Study of Power Output Characteristics for the Magnesium Metal Fuel Cell (마그네슘 금속연료전지의 출력특성에 관한 연구)

  • Kim, Yong-Hyuk
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.3
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    • pp.212-217
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    • 2014
  • The electric power output characteristics of magnesium fuel cell were investigated with regard to internal resistance. A equivalent circuit with the series-connected three internal resistance was introduced to analyze of the response to change of power. The power output analysis was employed in order to investigate the effect of internal resistances for the electrolyte concentration, air electrode area, Mg electrode area and distance between the electrodes. It was confirmed that internal resistance is generated by the electrolyte, air electrode and metal electrode, then those Internal resistances had a significant effect on the power output decrease. The power output was a maximum when the load resistance maches the internal resistance of the magnesium fuel cell. The fuel efficiency was only 50% at maximum power output. Higher fuel efficiency was achieved when the load resistance is greater than the internal resistance.

A Study of MPPT Control Algorithm for Boost Converter of Photovoltaic System Considering Capacitor Equivalent Series Resistance (커패시턴스 내부저항을 고려한 태양광용 Boost 컨버터에 대한 MPPT 제어 알고리듬 고찰)

  • Choi J. Y.;Yu G. J.;Lee D. G.;Lee K. O.;Jung Y. S.;Kim K. H.
    • Proceedings of the KIPE Conference
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    • 2001.12a
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    • pp.109-114
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    • 2001
  • Photovoltaic systems normally use a maximum power point tracking (MPPT) technique to continuously deliver the highest possible power to the load when variations in the insolation and temperature occur. A simple method of tracking the maximum power points (MPPs) and forcing the boost converter system to operate close to these points is presented through deriving small-signal model and transfer function of boost converter. This paper aims at modeling boost converter including equivalent series resistance of input reservoir capacitor by state-space-averaging method. In the future, properly designed controller for compensation will be constructed for maximum photovoltaic power tracking control.

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Effect of Non-Idealities on the Design and Performance of a DC-DC Buck Converter

  • Garg, Man Mohan;Pathak, Mukesh Kumar;Hote, Yogesh Vijay
    • Journal of Power Electronics
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    • v.16 no.3
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    • pp.832-839
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    • 2016
  • In this study, the performance of a direct current (DC)-DC buck converter is analyzed in the presence of non-idealities in passive components and semiconductor devices. The effect of these non-idealities on the various design issues of a DC-DC buck converter is studied. An improved expression for duty cycle is developed to compensate the losses that occur because of the non-idealities. The design equations for inductor and capacitor calculation are modified based on this improved expression. The effect of the variation in capacitor equivalent series resistance (ESR) on output voltage ripple (OVR) is analyzed in detail. It is observed that the value of required capacitance increases with ESR. However, beyond a maximum value of ESR (rc,max), the capacitor is unable to maintain OVR within a specified limit. The expression of rc,max is derived in terms of specified OVR and inductor current ripple. Finally, these theoretical studies are validated through MATLAB simulation and experimental results.

Designing Impedance Network at Quasi Z-Source Inverters by Considering ESR in the Capacitor (커패시터의 ESR을 고려한 Quasi Z-소스 인버터의 임피던스 네트워크 설계)

  • Yang, Jong-Ho;Chun, Tae-Won;Lee, Hong-Hee;Kim, Heung-Geun;Nho, Eui-Cheol
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.5
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    • pp.453-460
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    • 2012
  • This paper proposes the method to design the parameters of an impedance network at three-phase QZSI(quasi Z-source inverter) by considering an equivalent series resistance (ESR) in the capacitor. The equations of both two capacitor voltages and two inductor currents are derived at three operating modes of the QZSI. The capacitor voltage ripples caused by the ESR in the capacitor at the transition state of operating modes are calculated. Based on the ripples of both the capacitor voltages and inductor currents, the optimal values of capacitor and inductor are designed. The simulation studies using PSIM and experimental results with DSP are carried out to verify the performance of design method.

An Improvement On-Line Failure Diagnosis of DC Link Capacitor in PWM Power Converters (PWM 전력 컨버터에서 DC 링크 커패시터의 개선된 온라인 고장 진단)

  • Shon, Jin-Geun;Na, Chae-Dong
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.1
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    • pp.40-46
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    • 2010
  • DC link electrolytic capacitors are widely used in various PWM power converter system, such as adjustable speed driver(ASD) or DC/DC converter. Electrolytic capacitors, which is the most of the time affected by aging effect, plays a very important role for the power electronics system quality and reliability. This objective of this paper is to propose a improvement method to detect the rise of equivalent series resistor(ESR) in order to realize the online failure prediction of electrolytic capacitor for DC link of PWM power converter. The ESR detection scheme is based on the determination of the electrolytic capacitor AC losses calculated from voltage/current measurement using AC coupling. Therefore, the preposed online failure prediction method has the merits of easy ESR computation and circuit simplicity compare with BPF method. Simulation results show the veridity of the proposed on-line ESR estimation method.

A Development of Ethernet-Based Remote Diagnosis System for DC Voltage Smoothing Capacitor using DSP (DSP를 적용한 전력용 DC 평활 커패시터의 이더넷 원격 고장진단시스템 개발)

  • Shon, Jin-Geun
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.60 no.2
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    • pp.94-98
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    • 2011
  • Electrolytic power capacitors today form essential components for virtually any power electronic system such as DC/DC converter or UPS. Frequently, electrolytic capacitors for DC link voltage smoothing are the key components which determine the life cycle of the whole unit and often are responsible for converter breakdown failures. In this paper, ethernet-based remote diagnosis system for DC voltage smoothing capacitor using DSP control board is developed. To estimate the status of the capacitor, the equivalent series resistor(ESR) of the component has to be determined. The ESR detection scheme is based on the determination of the capacitor ripple power losses calculated from DC link voltage/current measurement. Experimental results show the veridity and reliability of the proposed ethernet-based remote on-line capacitor diagnosis system.

On-line Failure Detection Method of DC Output Filter Capacitor in Power Converters (전력변환장치에서의 DC 출력 필터 커패시터의 온라인 고장 검출기법)

  • Shon, Jin-Geun
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.4
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    • pp.483-489
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    • 2009
  • Electrolytic capacitors are used in variety of equipments as smoothening element of the power converters because it has high capacitance for its size and low price. 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. This objective of this paper is to propose a new method to detect the rise of equivalent series resistor(ESR) in order to realize the online failure prediction of electrolytic capacitor for DC output filter of power converter. The ESR of electrolytic capacitor estimated from RMS result of filtered waveform(BPF) of the ripple capacitor voltage/current. Therefore, the preposed online failure prediction method has the merits of easy ESR computation and circuit simplicity. Simulation and experimental results are shown to verify the performance of the proposed on-line method.

Equivalent-Circuit Analysis of Organic Light-Emitting Diodes in $ITO/TPD/Alq_3/Al$ ($ITO/TPD/Alq_3/Al$ 유기발광소자의 등가회로 분석)

  • Ahn, Joon-Ho;Oh, Yong-Chul;Hong, Jin-Woong;Lee, Joon-Ung;Song, Min-Jong;Kim, Tae-Wan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07a
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    • pp.188-191
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    • 2004
  • We have investigated equivalent-circuit analysis of organic light-emitting diodes in $ITO/TPD/Alq_3/Al$. Complex impedance Z of the device was measured in the frequency range of $40Hz{\sim}1MHz$. We are able to interpret the frequency-dependent response in terms of equivalent-circuit model of contact resistance $R_s$ in series with two parallel combination of $R_{TPD},\;C_{TPD}\;and\;R_{Alq3},\;C_{Alq3}$.

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The Effective Capacitance of a Constant Phase Element with Resistors in Series

  • Byoung-Yong, Chang
    • Journal of Electrochemical Science and Technology
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    • v.13 no.4
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    • pp.479-485
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    • 2022
  • The power of energy storage devices is characterized by capacitance and the internal resistance. The capacitance is measured on an assumption that the charges are stored at the electrode interface and the electric double layer behaves like an ideal capacitor. However, in most cases, the electric double layer is not ideal so a constant phase element (CPE) is used instead of a capacitor to describe the practical observations. Nevertheless, another problem with the use of the CPE is that CPE does not give capacitance directly. Fortunately, a few methods were suggested to evaluate the effective capacitance in the literature. However, those methods may not be suitable for supercapacitors which are modeled as an equivalent circuit of a CPE and resistor connected in series because the time constant of the equivalent circuit is not clearly studied. In this report, in order to study the time constant of the CPE and find its equivalent capacitor, AC and DC methods are utilized in a complementary manner. As a result, the time constants in the AC and DC domains are compared with digital simulation and a proper equation is presented to calculate the effective capacitance of a supercapacitor, which is extended to an electrochemical system where faradaic and ohmic processes are accompanied by imperfect charge accumulation process.