• Title/Summary/Keyword: lifetime

Search Result 3,616, Processing Time 0.136 seconds

Improvement on Switching Characteristics of IGBT by Means of Lifetime Control (Lifetime Control을 이용한 IGBT의 스위칭 특성 개선)

  • Lee, Se-Gyu;Jeong, Sang-Gu
    • The Transactions of the Korean Institute of Electrical Engineers C
    • /
    • v.49 no.3
    • /
    • pp.165-168
    • /
    • 2000
  • Improvement on the switching characteristic of IGBT by means of the uniform and local lifetime control is studied numerically using two-dimensional simulator, MEDICI. In the case of uniform lifetime control, the on-state and switching characteristics are simulated as a function of lifetime, and compared with the experimental results reported, which allows a relationship between dose of electron irradiation and controlled lifetime. In the case of local lifetime control, simulations are carried out by varying the position, width, and lifetime of the locally controlled region, and the results are compared with the characteristics for the case of the uniform lifetime control. The turn-off time of the device with an optimized locally controlled region is found to decrease from about $4.5\mus$ to 0.11$mutextrm{s}$ while the forward voltage drop increases from 1.37V to 2.61V in comparison with that for the uniform lifetime control.

  • PDF

An Study on Basis for Demand Estimation of Lifetime Sports Facilities (생활체육시설의 수요예측을 위한 기초적 연구)

  • Min, Young-Gi
    • Journal of The Korean Digital Architecture Interior Association
    • /
    • v.3 no.1
    • /
    • pp.15-22
    • /
    • 2003
  • The purpose of this study was to analyze basic conditions for the demand estimation erection of lifetime sports facilities. This is described the whole concept of lifetime sports(sport for all) for helping the understanding of its concept correctly. Firstly, second chapter was examined the significance, function and role of lifetime sports in modern society. Secondly, third and forth chapter was examined demand and participation of lifetime sports activities for demand estimation of lifetime sports facilities. Participation rate is on the rise by the increase in income and leisure time to some extent, but after that it stops rising. In other words, the same participation rate persists without additional increase in participation by the changes in time deepening and in the patterns of demand for lifetime sports activities.

  • PDF

Lifetime-Temperature Rise Model for the Evaluation of Degradation in Electric Connections/Contacts (전기적 접속/접촉부 열화 평가를 위한 수명 온도상승 모델)

  • Kim, Jeong-Tae;Kim, Nam-Jun
    • The Transactions of the Korean Institute of Electrical Engineers C
    • /
    • v.51 no.2
    • /
    • pp.55-61
    • /
    • 2002
  • In this paper, 'lifetime-temperature rise model' based on the 'lifetime-resistance model' is theoretically Proposed, in order to find out the evaluation method of degradation and the residual lifetime by use of infrared image camera for electric connections/contacts. Two assumptions have been builded up for the 'lifetime-temperature rise model': one is associated with the linear relationship between the temperature ism ΔK and contact resistance, and the other the functional relationship between the temperature of electric connections/contacts and the operating time presenting in the 'lifetime-resistance model'. To prove the proposed model, experiments have been performed for various electric connections/contacts. From the experimental results, measured values were quite similar to the calculated values, which proved the above-mentioned two assumptions. Therefore, by use of 'lifetime-temperature rise model', it is possible to estimate the trend of degradation and the residual lifetime for electric connections/contacts through the temperature measurements .

A Basic Study on Accelerated Life Test Method and Device of DSA (Dimensionally Stable Anode) Electrode (촉매성 산화물 전극 (DSA, Dimensionally Stable Anode)의 가속수명 테스트 방법과 장치에 관한 기초 연구)

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Environmental Science International
    • /
    • v.27 no.6
    • /
    • pp.467-475
    • /
    • 2018
  • The lifetime of the electrode is one of the most important factors on the stability of the electrode. Since the lifetime of the DSA (Dimensionally stable anode) electrode is long, an accelerated lifetime test is required to reduce the test time. Beacuse there is no basis or standard method for accelerated lifetime testing, many researchers use different methods. Therefore, there is a need for basis and methods for accelerated lifetime testing that other researchers can follow. We designed a reactor system for accelerated lifetime testing and planned specific methods. Reactor system was circulating batch reactor. Reactor volume and cooling water tank were 12.5 L and 100 L, respectively. Electrode size was $2cm{\times}3cm$ (real electrolysis area, $5cm^2$). In order to maintain the harsh conditions, accelerated lifetime test was carried out in a high current density ($0.6A/cm^2$) and low electrolyte concentration (NaCl, 0.068 mol/L). Maintaining a constant temperature was an important operation parameter for exact accelerated lifetime test. As the accelerated lifetime test progressed, the active component of electrode surface was consumed and desorption occurred. At the point of 5 V rise, corrosion of the surface of the base material(titanium) also started.

Analysis of Orbital Lifetime Prediction Parameters in Preparation for Post-Mission Disposal

  • Choi, Ha-Yeon;Kim, Hae-Dong;Seong, Jae-Dong
    • Journal of Astronomy and Space Sciences
    • /
    • v.32 no.4
    • /
    • pp.367-377
    • /
    • 2015
  • Atmospheric drag force is an important source of perturbation of Low Earth Orbit (LEO) orbit satellites, and solar activity is a major factor for changes in atmospheric density. In particular, the orbital lifetime of a satellite varies with changes in solar activity, so care must be taken in predicting the remaining orbital lifetime during preparation for post-mission disposal. In this paper, the System Tool Kit (STK$^{(R)}$) Long-term Orbit Propagator is used to analyze the changes in orbital lifetime predictions with respect to solar activity. In addition, the STK$^{(R)}$ Lifetime tool is used to analyze the change in orbital lifetime with respect to solar flux data generation, which is needed for the orbital lifetime calculation, and its control on the drag coefficient control. Analysis showed that the application of the most recent solar flux file within the Lifetime tool gives a predicted trend that is closest to the actual orbit. We also examine the effect of the drag coefficient, by performing a comparative analysis between varying and constant coefficients in terms of solar activity intensities.

Effects of the Local Lifetime Control on the Switching and Latch-up Characteristics of IGBT (Local Lifetime Control이 TGBT의 스위칭 및 래치업 특성에 미치는 영향)

  • Lee, Se-Kyu;Chung, Sang-Koo
    • Proceedings of the KIEE Conference
    • /
    • 1999.07d
    • /
    • pp.1953-1955
    • /
    • 1999
  • The effects of the local lifetime control on the characteristics of IGBT are investigated using the 2-dimensional device simulator, MEDICI. Many lumped resistive turn-off simulations are carried out to analyze the effects of the minority carrier lifetime, the width, and the position of the region with a reduced local minority carrier lifetime. As a result of these simulations, it is concluded that the on state voltage drop$(V_{CE,SAT})$ is only slightly increased while the switching behavior is greatly improved if the low lifetime region is properly set. And these results are compared with IGBTs having uniform lifetime.

  • PDF

Lifetime Temperature Rise Model for the Degradation of Electric Connections/Contacts (도체접속부 열화에 대한 수명온도상승 모델)

  • Kim, Jeong-Tae;Kim, Ji-Hong;Koo, Ja-Yoon;Yoon, Ji-Ho;Ham, Gil-Ho
    • Proceedings of the KIEE Conference
    • /
    • 2000.07c
    • /
    • pp.1611-1613
    • /
    • 2000
  • In this study in order to find out the trends and the residual lifetime for electric connections/contacts using infrared image camera, "lifetime temperature rise model" is theoretically proposed on the base of "lifetime resistance model" and to prove this theory, experiments have been performed for various kinds of electric connections/contacts. Two suggestions have been builded up or the "lifetime temperature rise model" ; one is the linear relationship between the temperature rise $\Delta K$ and contact resistance, and the other is the functional relationship between the temperature of electric connections/contacts and the operating time which ascribed in the "lifetime resistance model". From the experimental results, measured values were quite similar to the theoretical value so that two suggestions in "lifetime temperature rise model" were appeared to be correct.

  • PDF

A Lifetime-based Cache Policy for Stable Data Distribution in NDN (NDN에서 안정성 있는 데이터 배포를 위한 Lifetime 기반의 캐시 정책)

  • CHOI, SU-HO;JOE, IN-WHEE
    • Proceedings of the Korea Information Processing Society Conference
    • /
    • 2019.05a
    • /
    • pp.92-95
    • /
    • 2019
  • CDN은 여러 서버에 데이터를 분산하여 캐시 한 뒤 빠르게 데이터를 배포하는 네트워크이다. 하지만 CDN은 서버 성능에 영향을 받고 데이터의 Lifetime이 얼마 없는 경우 중앙 서버 혹은 데이터 제작자와의 통신을 통해 데이터를 새로 받아야 한다. 반면에, NDN은 데이터를 라우터별로 캐시하여 트래픽을 분산시키고 딜레이를 줄였다. 하지만, 캐시 된 데이터의 Lifetime에 따라 데이터를 받지 못하는 문제가 있다. 본 논문에선 데이터 요청자가 Lifetime 내에 데이터를 못 받으면 요청자의 네트워크 상황과 Interest 패킷의 주기를 고려하여 캐시 된 데이터의 Lifetime을 증가시켜 안정성 있는 데이터 배포를 목표로 하였다. 캐시 정책이 적용된 시뮬레이션을 진행했으며, 얼마 남지 않은 Lifetime을 증가시켜 데이터 요청자가 데이터를 온전히 받을 수 있음을 확인하였다.

Lifetime Maximization with Cooperative Wireless Energy Sharing in Wireless Multi-Hop Communications (무선 멀티 홉 통신에서 협력적인 무선 에너지 공유를 통한 생존시간 최대화)

  • Choi, Hyun-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.24 no.11
    • /
    • pp.1550-1553
    • /
    • 2020
  • In this paper, we maximize the lifetime of a multi-hop path through a cooperative wireless energy sharing scheme between constituent nodes in a wireless multi-hop communication. Considering a bidirectional multi-hop communication environment, we present an optimization problem to maximize path lifetime by adjusting the amount of energy each node needs to share with its neighboring nodes. On the basis of solidarity property, i.e., the lifetime of the multi-hop path is maximized when the lifetimes of all nodes are the same, we convert the considered optimization problem into a linear programming problem and solve it easily. Simulation result shows that the proposed two-way wireless energy sharing method maximizes the path lifetime of multi-hop communications and approximately doubles the path lifetime compared with the one-way energy sharing method.

Lifetime Management Method of Lithium-ion battery for Energy Storage System

  • Won, Il-Kuen;Choo, Kyoung-Min;Lee, Soon-Ryung;Lee, Jung-Hyo;Won, Chung-Yuen
    • Journal of Electrical Engineering and Technology
    • /
    • v.13 no.3
    • /
    • pp.1173-1184
    • /
    • 2018
  • The lifetime of a lithium-ion battery is one of the most important issues of the energy storage system (ESS) because of its stable and reliable operation. In this paper, the lifetime management method of the lithium-ion battery for energy storage system is proposed. The lifetime of the lithium-ion battery varies, depending on the power usage, operation condition, and, especially the selected depth of discharge (DOD). The proposed method estimates the total lifetime of the lithium-ion battery by calculating the total transferable energy corresponding to the selected DOD and achievable cycle (ACC) data. It is also demonstrated that the battery model can obtain state of charge (SOC) corresponding to the ESS operation simultaneously. The simulation results are presented performing the proposed lifetime management method. Also, the total revenue and entire lifetime prediction of a lithium-ion battery of ESS are presented considering the DOD, operation and various condition for the nations of USA and Korea using the proposed method.