• Title/Summary/Keyword: Capacitor lifetime

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The best accelerated method and lifetime prediction of electrolytic capacitors (전해 캐패시터의 최적 가속시험방법과 수명예측)

  • Kim, Ha-Na;Sim, Chan-Ho;Kim, Sung-Jun;Yoon, Jung-Rag;Lee, Hun-Yong
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.1945-1947
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    • 2005
  • This study considers find out best accelerated life testing and lifetime prediction of electrolytic capacitors. We proved about relation between failure and deterioration mechanism from last thesis. Beside we performed test that temperature and voltage press higher than allowance specification. Failure distribution acquired from those test. And wiebull function and Minitab program applied to accelerated constant and lifetime by means of calculation. At the result, goodness of fit affect to weibull function and acceleration factor therefore fitting is important factor in reliability testing.

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AC-DC Converter for Electrolytic Capacitor-less LED Driver with Reduced LED Peak Current (LED 구동전류의 피크값이 저감된 전해 커패시터 없는 AC-DC 컨버터)

  • Kang, Kyoung-Suk;Park, Gwon-Sik;Seo, Byung-Jun;Nho, Eui-Cheol
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.1
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    • pp.59-65
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    • 2018
  • A new single-stage flyback power converter with PFC for electrolytic capacitor-less LED driver is proposed in this study. This method minimizes the peak-to-average ratio of the LED driving pulsating current by adding the LED driving current near the LED current valley area, as well as the third harmonic component injection into the input current. The reduced peak current value of the LED drive current minimizes the thermal stress of the LED itself, thereby increasing the reliability of the LED, as well as achieving a long lifetime. Simulation and experimental results show the usefulness of the proposed topology.

Third Harmonic Injection Circuit to Eliminate Electrolytic Capacitors in Light-Emitting Diode Drivers

  • Yoo, Jin-Wan;Jung, Kwang-Hyun;Jeon, In-Ung;Park, Chong-Yeun
    • Journal of Electrical Engineering and Technology
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    • v.7 no.3
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    • pp.358-365
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    • 2012
  • A new third harmonic injection circuit for light-emitting diode (LED) drivers is proposed to eliminate electrolytic capacitors and thereby extend the lifetime of LED drivers. When a third harmonic current is injected to the input current of the LED driver, the required capacitance of the driver can be reduced. The proposed circuit can control an injection ratio and has simple circuitry. The synchronous third harmonic is generated by a phase locked loop (PLL), a 1/3 counter, and op-amps and applied to a power factor correction circuit. Thus, the storage capacitor can install film capacitors instead of the electrolytic capacitor. The value of storage capacitance can be reduced to 78% compared to an input power factor of 100%. The proposed circuit is applied to the 80W prototype LED driver to experimentally verify the performances.

Single Phase Grid Connected Voltage-ed Inverter Utilizing a Power Decoupling Function (전력 디커플링 기능을 가진 단상 계통연계 전압형 인버터)

  • Lee, Sang-Wook;Mun, Sang-Pil;Park, Han-Seok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.66 no.4
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    • pp.236-241
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    • 2017
  • This paper presents a single-phase grid connected voltage-ed inverter with a power decoupling circuit. In the single-phase grid connected voltage-ed inverter, it is well known that a power pulsation with twice the grid frequency is contained in the input power. In a conventional voltage type inverter, electrolytic capacitors with large capacitance have been used in order to smooth the DC voltage. However, lifetime of those capacitors is shortened by the power pulsation with twice grid frequency. The authors have been studied a active power decoupling(APD) method that reduce the pulsating power on the input DC bus line, this enables to transfer the ripple energy appeared on the input DC capacitors into the energy in a small film capacitor on the additional circuit. Hence, extension of the lifetime of the inverter can be expected because the small film capacitor substitutes for the large electrolytic capacitors. Finally, simulation and experimental results are discussed.

Optimal Allocation of Shunt Capacitor-Reactor Bank in Distribution System with Dispersed Generators Considering Installation and Maintenance Cost (분산전원을 포함한 배전계통에서 설치비용과 유지보수 비용을 고려한 병렬 캐패시터-리액터 Bank의 최적 설치 위치 선정)

  • Heo, Jae-Haeng;Lyu, Jae-Kun;Lee, Woo-Ri;Park, Jong-Young;Park, Jong-Keun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.11
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    • pp.1511-1519
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    • 2013
  • This paper proposes the allocation method for capacitor-reactor banks in a distribution system with dispersed generators to reduce the installation costs, the maintenance costs and minimize the loss of electrical energy. The expected lifetime and maintenance period of devices with moving parts depends on the total number of operations, which affects the replacement and maintenance period for aging equipment under a limited budget. In this paper, the expected device lifetimes and the maintenance period are included in the formulation, and the optimal operation status of the devices is determined using a genetic algorithm. The optimal numbers and locations for capacitor-reactor banks are determined based on the optimal operation status. Simulation results in a 69-bus distribution system with the dispersed generator show that the proposed technique performs better than conventional methods.

A New Volt/Var Control of Substation for Distribution Volt/Var Regulation (배전계통 전압/무효전력조정을 위한 새로운 전압/무효전력제어 방식)

  • Choi, Joon-Ho;Kim, Jae-Chul;Son, Hag-Sig;Im, Tae-Hoon
    • Proceedings of the KIEE Conference
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    • 2001.07a
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    • pp.285-288
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    • 2001
  • In this paper we proposed the on line volt/var control schemes of the load Tap Changer (LTC) transformer and shunt capacitor bank for distribution volt/var regulation. In the existing volt/var control of the distribution substation, the voltage of feeders and var of distribution systems is mainly controlled by the LTC transformer tap position and on/off status of the shunt capacitor. The LTC and shunt capacitor bank has discrete operation characteristics and therefore it is very difficult to control volt/var at the distribution networks within the satisfactory levels. Also there is limitation of the operation times of the LTC and shunt capacitor bank because it is affects on their functional lifetime. The proposed volt/var control algorithm determine an optimal tap position of LTC and on/off status of shunt capacitors at a distribution network with the multiple feeders. The mathematical equations of the proposed method are introduced. Simple case study was performed to verify the effectiveness of the proposed method.

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Cooperation Algorithms of LTC and SC for Distribution Volt/Var Regulation (배전계통 전압/무효전력 보상을 위한 LTC변압기와 SC의 협조운전 알고리즘)

  • Choi, Joon-Ho;Kim, Jae-Chul;Nam, Hae-Kon;Moon, Seung-Il
    • Proceedings of the KIEE Conference
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    • 2003.07a
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    • pp.399-402
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    • 2003
  • In this paper, the on line volt/var control algorithms of the food Load Tap Changer (LTC) transformer and Shunt Capacitor(SC) are proposed for distribution volt/var regulation. In the existing volt/var control of the distribution substation, the voltage of feeders and var of distribution systems is mainly controlled by the LTC transformer tap position and on/off status of the shunt capacitor. The LTC and shunt capacitor bank has discrete operation characteristics and therefore it is very difficult to control volt/var at the distribution networks within the satisfactory levels. Also there is limitation of the operation times of the LTC and shunt capacitor bank because it is affects on their functional lifetime. The proposed volt/var control algorithm determine an optimal tap position of LTC and on/off status of shunt capacitors at a distribution network with the multiple feeders. The mathematical equations of the proposed method are introduced. Simple case study was performed to verify the effectiveness of the proposed method.

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DC Traction Regenerative Energy Storage Devices using Super-capacitor (슈퍼 커패시터를 이용한 직류철도 회생에너지 저장장치)

  • Kim, Jong-Yoon;Jung, Doo-Yong;Jang, Su-Jin;Lee, Byoung-Kuk;Won, Chung-Yuen
    • The Transactions of the Korean Institute of Power Electronics
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    • v.13 no.4
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    • pp.247-256
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    • 2008
  • Regenerative energy generated by regenerative braking of DC traction can cause the system malfunction or damage to the rectifier, or malfunction of the power conversion device in power supply system by DC Line voltage rise in feeder line. Regenerative energy storage system using super capacitor is one of the ways to stabilize DC line voltage. In this paper, energy storage system of DC traction system using super-capacitor bank is implemented and using the field measurement data of the station N and the station S on the Line 2, the operation characteristics of line voltage caused by regenerative energy of electric trains are verified. Also, charge/discharge characteristics of super capacitor are verified as well. Thus, we can verify the operation characteristics of super-capacitor bank for regenerative energy storage system installed in DC Traction. And if we can use field measurement data of DC line voltage, we have obtained cost reduction. The stabilization of the system will be improved by measuring the operation characteristics of regenerative energy storage system in certain section operated by DC traction and predicting the capacity and lifetime of super-capacitor.

A Telemetry Silicon Pressure Sensor of LC Resonance Type (LC공진을 이용한 원격측정용 압력센서의 제작 및 실험)

  • Kim, Hak-Jin;Kim, Soon-Young;Yang, Sang-Sik
    • Proceedings of the KIEE Conference
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    • 2001.07c
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    • pp.1872-1874
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    • 2001
  • This paper presents an implantable telemetry LC resonance-type pressure sensor to measure the cerebral ventricle pressure. The sensor consists of an inductor and a capacitor. The LC resonant circuit consists of the sensor and an external antenna coil that are coupled magnetically. The resonance frequency of the circuit decreases as the applied pressure increases the capacitance of the sensor. The sensor is designed in consideration of the biocompatibility and long lifetime for continuous monitoring of the ventricle pressure. The sensor is simple to fabricate and small in comparison with others reported previously. The inductor is fabricated by electroplating and the variable capacitor is constructed with a flexible p+ diaphragm. Also, the deflection of the diaphragm, the variation of the capacitance and the resonance frequency are analyzed and calculated.

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C-T Characteristics of Nitridized MOS Capacitor (질화된 MOS 커패시터의 C-T 특성)

  • Chang, Eui-Goo;Choi, Won-Eun;Seo, Yong-Jin;Choi, Hyun-Sik;Yu, Seok-Bin
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.788-791
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    • 1988
  • The C-T characteristics of nitridized MOS capacitor have been studied. The generation lifetimes were calculated using C-T transient response ans found to vary as sample condition. This is due to the non-uniformity of fast surface state. Also, This experimental curves were different from theoretical curves. The result suggests that the change in material structure (from SiO2 to Si-N-O) is important in improving minority carrier lifetime.

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