• 전기학회논문지
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• 제62권7호
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• pp.937-942
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• 2013

Equivalent series impedance of high-voltage pulsed power capacitor is one of the important electrical characteristics both for users and for capacitor manufacturers because it may have serious effects on the performance of pulse forming circuits. In this paper, definition of equivalent series impedance and factors which generate equivalent series impedance are reviewed. Theoretical analysis for the calculation of equivalent series impedance based on differential measurement method is described and calculation program has been developed. In order to acquire data which are necessary to calculate equivalent series impedance from discharging current waveform, charging-dischargig controller has been manufactured. Measurement results of equivalent series impedance for high voltage pulsed power capacitor have been given.

• Journal of Electrochemical Science and Technology
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• 제11권3호
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• pp.318-321
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• 2020

Here I present a formula which converts a constant phase element (CPE) to its equivalent capacitor. Electrochemical impedance spectroscopy is capable of resolving a complex electrochemical processes into its faradaic and non-faradaic elements, and the non-faradaic process is frequently described as a CPE in place of a capacitor due to the non-ideality. Being described as a capacitor, the non-faradaic element provides information by its capacitance, but a CPE cannot provide a physical meaning. In order to solve the problem, the CPE has been dealt with as an equivalent capacitor of which the capacitance provides practical information. Succeeding the two methods previously suggested, a new conversion method is suggested in this report. While the previous ones manipulate only the CPE, the new method takes both the CPE and its related resistor into account for conversion. By comparing the results obtained by the three methods, we learn that the results are nearly the same within tolerable ranges, and conclude that any of the method choices is acceptable depending on the conditions of the system of interest.

• 전력전자학회논문지
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• 제12권5호
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• pp.372-377
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• 2007

본 논문은 가변속 구동 장치에서 직류링크 전압 평활용으로 사용되는 전해 커패시터의 새로운 고장 진단 방법을 제안한다. 전해 커패시터의 등가직렬저항은 직류링크 전압과 부하 전류로부터 직접 추정되고, 추정된 등가직렬저항으로부터 전해 커패시터의 상태가 결정된다. 온도 변동에 따른 등가직렬저항 변동을 보상하기 위해, 커패시터 주변의 PCB에 다이오드를 부착하고 다이오드의 전압 강하로부터 커패시터의 온도를 간접적으로 검출한다. 시뮬레이션 및 실험은 제안된 방식의 효용성을 보인다.

• 전기학회논문지P
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• 제60권4호
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• pp.220-226
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• 2011

This paper proposes a straightforward method of analyzing the operation characteristics for the capacitor run single-phase induction motor from the traditional equivalent circuit based on the revolving field theory. The proposed method consists of five procedures as follows: mechanical loss segregation, iron loss segregation and calculation of the equivalent circuit parameters, recalculation of parameters of the main winding side, calculation of the auxiliary winding magnetizing reactance and effective turn ratio, and analyzing the operation characteristics for this motor. When the characteristics are analyzed, the segregated mechanical and iron losses are considered as a loss resistance across input terminals of the equivalent circuit for the analysis. The validity of the proposed method is verified from the comparison between the computed results and the experimental ones for the operation characteristics.

• 전기학회논문지P
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• 제59권4호
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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.

• 전기학회논문지P
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• 제58권2호
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• pp.207-213
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• 2009

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. This paper proposed a novel fault diagnosis method of an electrolytic capacitor used for voltage smoothing in boost DC converter. The equivalent series resistance(ESR) of electrolytic capacitor estimated from FFT result of filtered waveform of capacitor voltage/current. Main advantage of the proposed method include circuit simplicity and easy implementation. Simulation and experimental results are shown to verify the performance of the proposed method.

• 전기학회논문지P
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• 제60권2호
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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.

• 전기학회논문지P
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• 제58권4호
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1506-1508
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• 2001

We have investigated for the modeling and the simulation of the ferroelectric capacitor and MFS TFT (Metal-Ferroelectric-Semiconductor Thin Film transistor). For ferroelectric capacitor modeling, we adopted the equivalent circuit model which consists of a nonlear capacitor, a nonliner resistor, and a linear capacitor. MFS TFT have been modeled by combining the ferroelectric capacitor and Bsim3 MOSFET model. Our simulations show the characteristics of ferroelectric capacitor and MFS TFT.

• 한국ITS학회 논문지
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• 제8권6호
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• pp.173-179
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• 2009

본 논문에서는 순시전압강하 보상장치 등의 전력변환시스템에 사용되는 수퍼 커패시터(또는 전기이중층콘덴서; EDLC)의 고장진단을 위한 파라미터의 측정기법에 관한 연구를 수행하였다. 직류 에너지의 저장을 위한 기존의 장치에는 납축전지 또는 전해 커패시터를 사용하여 왔으나 환경문제 및 에너지밀도의 측면에서 불리하여 최근에는 수퍼 커패시터의 사용이 주목을 받고 있다. 따라서 본 논문에서는 이러한 수퍼 커패시터의 내부 특성 및 고장 마모 등을 분석하기 위한 커패시터의 등가직렬저항(ESR) 및 정전용량을 측정하는 기법을 제시하여 고장진단의 주요한 데이터에 활용이 가능토록 하였으며, 또한 수퍼 커패시터를 적용한 순간전압강하에 대한 응용 실험을 수행하여 그 결과를 함께 제시하였다.