• 전기학회논문지
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• 제62권11호
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• pp.1550-1559
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• 2013

Light emitting diode(LED) lighting has been applied various industry fields because of its high efficiency, low power consumption, long life time, and environment friendly characteristics. Generally, LED lighting needs a driver to maintain constant current. Most popular driver is the switching converter. In the converter, there are several electrolytic capacitors. However the lifespan of the electrolytic capacitor is much shorter than LED. Therefore the lifespan of LED lighting with electrolytic capacitor is decreased. Also, LED lighting needs dimming control because of various needs and energy saving. This paper presents the dimmable single-stage PFC DCM flyback converter without electrolytic capacitor and parallel LC resonant filter for reducing 120[Hz] ripple on the output. The type 2 controller is used to maintain constant current and the analog dimming control is used. The proposed converter is verified through simulation and experimental works.

• 전기학회논문지P
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• 제61권4호
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• pp.186-191
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• 2012

DC Bus Electrolytic capacitors have been widely used in power conversion system because they can achieve high capacitance and voltage ratings with volumetric efficiency and low cost. This type of capacitors have been traditionally used for filtering, voltage smoothing, by-pass and other many applications in power conversion circuits requiring a cost effective and volumetric efficiency components. Unfortunately, electrolytic capacitors are some of the weakest components in power electronic converter. Many papers have proposed different methods or algorithms to determinate the ESR and/or capacitance C for fault diagnosis of the electrolytic capacitor. However, both ESR and C vary with frequency and temperature. Accurate knowledge of both values at the capacitors operating conditions is essential to achieve the best reference data of fault judgement. According to parameter analysis, the capacitance increases with temperature and the ESR decreases. Higher frequencies make the ESR and C to decrease. Analysis results show that the proposed electrolytic capacitor parameter estimation technique can be applied to reference signal of capacitor diagnosis systems successfully.

• 한국ITS학회 논문지
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• 제8권6호
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• pp.180-186
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• 2009

DC/DC 컨버터 등의 전력변환장치와 같은 비선형부하에 대해 알루미늄 전해 커패시터는 에너지의 일시적 저장이나 전압 평활용으로 많이 사용되고 있다. 그러나 전해 커패시터는 사용 시간이 늘어나면서 온도 상승 및 전해액(electrolyte)의 증발 등으로 인하여 고장이 매우 빈번하게 나타난다. 따라서 본 논문에서는 이러한 사고에 대한 고장모드를 분류하고 이를 진단하기 위한 사전 단계로 전해 커패시터의 주파수 변화에 따른 특성 해석과 이를 바탕으로 한 커패시턴스 용량 추정 알고리즘을 제안하였다. 기본파에 해당하는 저주파의 주파수 분석 결과에 따른 모의 실험의 결과는 제안한 알고리즘의 타당성을 입증하였다.

• 전기학회논문지P
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• 제59권1호
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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.

• 전기학회논문지P
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• 제61권1호
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• pp.41-46
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• 2012

Electrolytic power capacitors have been widely used in power conversion system such as inverter or UPS because of characteristics of large capacitance, high-voltage and low-cost. The electrolytic capacitor, which is most of the time affected by the aging effect, plays a very important role for the power-electronics system quality and reliability. Therefore it is important to diagnosis monitoring the condition of an electrolytic capacitor in real-time to predict the failure. In this paper, the on-line remote diagnosis monitoring system for UPS DC link electrolytic capacitors using low-cost single-chip zigbee communication modules is developed. To estimate the health status of the capacitor, the equivalent series resistor(ESR) of the component has to be determined. The capacitor ESR is estimated by using RMS computation using BPF modeling of DC link ripple voltage/current. Zigbee-based hardware experimental results show that the proposed remote capacitor diagnosis monitoring system can be applied to UPS successfully.

• 전기학회논문지P
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• 제66권4호
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• pp.213-218
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• 2017

The DC electrolytic capacitor for DC-link of power converter is widely used in various power electronic circuits and system application. Its functions include, DC Bus voltage stabilization, conduction of ripple current due to switching events, voltage smoothing, etc. Unfortunately, DC electrolytic capacitors are some of the weakest components in power electronics converters. Many papers have proposed different algorithms or diagnosis method to determinate the ESR and tan ${\delta}$ capacitance C for fault alarm system of the electrolytic capacitor. However, both ESR vary with frequency and temperature. Accurate knowledge of both parameters at the capacitors operating conditions is essential to achieve the best reference data of fault alarm. According to parameter analysis, the capacitance increases with temperature and the initial ESR decreases. Higher frequencies make the reference ESR with the initial ESRo value to decrease. Analysis results show that the proposed DC Bus electrolytic capacitor reference ESR model setting technique can be applied to advanced reference signal of capacitor diagnosis systems successfully.

• 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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• 제64권1호
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• pp.29-34
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• 2015

DC bus electrolytic capacitors are used in variety of equipments as smoothing element of the power converters because it has high capacitance for its size and low price. It is responsible for frequent breakdowns of many static converters and inverter drive systems. Therefore it is important to diagnosis monitoring the condition of an electrolytic capacitor in real-time to predict the failure of power converter. In this paper, the on-line remote diagnosis monitoring system for DC BUS electrolytic capacitors of power converter using low-cost type Zigbee communication modules is developed. To estimate the health status of the capacitor, the equivalent series resistor(ESR) of the component has to be determined. The capacitor ESR is estimated by using RMS computation using AC coupling method of DC link ripple voltage/current. The Zigbee communication-based experimental results show that the proposed remote DC capacitor diagnosis monitoring system can be applied to DC/DC converter and UPS successfully.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권7호
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• pp.338-346
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• 2001

In this paper, dc link currents for the three-phase diode rectifiers and PWM inverters are analyzed and an algorithm of estimating the life of dc link electrolytic capacitors using the analyzed ripple current is presented. Since the capacitor life is dependent on the operating temperature, the power dissipation in capacitors should be calculated. For this, the ESR(equivalent series resistance) model of the capacitor is derived and ripple currents through the capacitor are analyzed. Relating the power dissipation and the heat transfer equation, the internal operating temperature is calculated. Then, the capacitor life can be predicted by using Arrhenius's equation. An example for applications is given for the practical system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.55-56
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• 2012

In general, a power decoupling method using electrolytic capacitor is used to solve a problem that appears 120[Hz] ripple of grid at the PV module output. But electrolytic capacitor has a effect on the short lifetime and low reliability of PV system. Therefore, studies which replace the large electrolytic capacitor with small film capacitor have been researched in resent years. This paper proposes flyback inverter which can be replaced with film capacitor by connecting the circuit implementing zero voltage switching in PV side. The proposed system is validated by PSIM simulation.