• Title/Summary/Keyword: Power Supply System

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Fusing Time Characteristics Analysis of Cable according to Temperature and Insulator (온도 및 절연체에 따른 케이블의 단선시간 특성 해석)

  • Kim, Ju-Hee;Kang, Sin-Dong;Kim, Jae-Ho
    • Journal of the Korean Society of Safety
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    • v.33 no.5
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    • pp.15-20
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    • 2018
  • This paper describes the fusing time characteristics of Light PVC Sheathed Circular Cord(VCTF) and Tray Frame Retardant(TFR) cables according to increased temperature under over current condition. The experimental equation will be used to determine the validity and reliability of the test results. The over current flowed 3, 5 and 10 times higher than the amount of allowable current using DC power supply with DAQ(Data Acquisition) measurement system. An infrared radiation heater, which was controlled by a variable AC auto transformer, was used to increase the temperature from room temperature to 50, 100 and 150 degrees Celsius. First, two type of cables were analyzed those with different cross-sectional areas with in the same structure and those with different structures with in the same cross-sectional areas. Then, it was determined how fusing time had been influenced according to the cross-sectional areas and different structures, respectively. The cable resistance was increased by joule heating according to increasing temperature. Therefore, the allowable current of cable is decreased. Finally, the fusing time of the cable was decreased due to increased temperatures at current flow, which were 3 times the amount of allowable current. The instantaneous breakdown was observed when current flow was 5 and 10 times over the amount of allowable current. The fusing time is directly affected by the structure of cable insulation.

A 0.13 ㎛ CMOS Dual Mode RF Front-end for Active and Passive Antenna (능·수동 듀얼(Dual) 모드 GPS 안테나를 위한 0.13㎛ CMOS 고주파 프론트-엔드(RF Front-end))

  • Jung, Cheun-Sik;Lee, Seung-Min;Kim, Young-Jin
    • Journal of Advanced Navigation Technology
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    • v.13 no.1
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    • pp.48-53
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    • 2009
  • The CMOS RF front-end for Global Positioning System(GPS)are implemented in 1P8M CMOS $0.13{\mu}m$ process. The LNAs consist of LNA1 with high gain and low NF, and LNA2 with low gain and high IIP3 for supporting operation with active and passive antenna. the measured performances of both LNAs are 16.4/13.8 dB gain, 1.4/1.68 dB NF, and -8/-4.4 dBm IIP3 with 3.2/2 mA form 1.2 V supply, respectively. The quadrature downconversion mixer is followed by transimpedance amplifier with gain controllability from 27.5 to 41 dB. The front-end performances in LNA1 mode are 39.8 dB conversion gain, 2.2 dB NF, and -33.4 dBm IIP3 with 6.6 mW power consumption.

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A Study on the Life Cycle Cost Calculation of the Railroad Vehicle Based on the Maintenance Information (철도차량 유지보수정보를 이용한 수명주기비용 계산 연구)

  • Kim, Jae-Hoon;Jun, Hyun-Kyu;Park, Jun-Seo;Jeong, Hyun-Yong
    • Journal of the Korean Society for Railway
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    • v.12 no.1
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    • pp.88-94
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    • 2009
  • Life cycle costing is one of the most effective approaches for the cost analysis of long-life products such as the railroad vehicle. Life cycle costing includes the cost of concept design, development, manufacture, operation, maintenance and disposal. Especially, life cycle costing in the railroad industry has been focused on the maintenance cost. In this paper, the standard, guide and maintenance information of railroad vehicle were investigated, and the unique corrective and preventive maintenance templates of railroad vehicle were proposed. Maintenance cost of an auxiliary power supply system of EMU was predicted by using the proposed templates. The results show that the preventive maintenance, PM, cost is much higher compare to corrective maintenance, CM, cost because of daily and monthly maintenance tasks which require lots of labor work. It is expected that these templates can help railroad operators make maintenance strategies with consideration of the cost parameter.

Design of high slew-rate OTA for DC-DC converters (DC-DC 컨버터용 높은 슬류율의 OTA 설계)

  • Kim, In-Suk;Ryu, Seong-Young;Roh, Jeong-Jin
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.43 no.10 s.352
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    • pp.118-125
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    • 2006
  • A new error amplifier is presented for fast transient response of DC-DC converters. The amplifier has low quiescent current to achieve high power conversion efficiency, but it can supply sufficient current during large signal operation. Two comparators detect large-signal variations, and turn on extra current supplier if necessary. The amount of extra current is well controlled, so that the system stability can be guaranteed in various operating conditions. The simulation results show that the new error amplifier achieves significant improvement in transient response than the conventional one.

The Design of LLC-typed Resonant Converter with Ga-N HEMT PFC and SR method for Electric Vehicle (Ga-N HEMT PFC 및 SR기법이 적용된 전기자동차용 LLC 공진형컨버터의 설계)

  • Yoo, DongJoo;Chun, Ji-Yong
    • Journal of the Korea Convergence Society
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    • v.8 no.11
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    • pp.313-319
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    • 2017
  • In this paper, we present a design technique that miniaturises the DC-DC converter, a key component in the electric vehicle system, using the advanced material (Ga-N HEMT) in the LLC resonant converter and freely changes the resonant frequency. This design is also proposed to improve the efficiency and temperature characteristics by adding SR Topology in the secondary side output during the operation of power supply. In this experiment, as a consequence of the constructed circuit with the operation of high switching frequency of 200 kHz, the size of LLC and PFC was able to be minimised by 40[%]. Thus, the characteristics of operating temperature demonstrated $60-65^{\circ}C$ without a heat sink, when the temperature was measured at 250W (12V/20A). The features were all due to the advantages of the change of switching frequency, switching circuits implementation, and the maximisation of switching frequency. Based on these design results, we would like to implement more than 1 [kW].

A Study of the Development of Apartment's Structural Cost Saving Checklist through the Case Research (사례분석을 통한 공동주택 골조공사의 원가절감 체크리스트 개발에 관한 연구)

  • Lee, Kyeong-Seob;Suh, Sang-Wook
    • Korean Journal of Construction Engineering and Management
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    • v.11 no.6
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    • pp.65-77
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    • 2010
  • Our nation's housing construction is given much weight over 32% in 2007 and especially apartment is taking over 67%. If we put into construction environment consideration, we are having a trouble with price cap policy and the realestate recession due to the global economic crisis. So in order to get competitive power and supply of cheap apartment, the necessity of cost saving is increasing. This research collected the past constructed apartment project's cost saving examples which were influencing on the construction cost, quality and time. We analyzed collected cost saving datum and assorted these in compliance with classification system. By analysis of correlation among datum with exclusion and integration, we make a propose cost saving Checklist that will be a base data to give a chance to use in working level and other research.

Study on Expansion of Output Point for PLC Output Unit (PLC 출력 Unit의 출력 점수 확장에 관한 연구)

  • You Jeong-Bong;Jeon Ho-Ik;Nam Sang-Yep
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.42 no.3 s.303
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    • pp.25-32
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    • 2005
  • PLC is the most widely utilized among many sorts of existing controller for the design of process control system, and study about a PLC language is performed actively. In this paper, we proposed the method that we increase an output points when increased of the output machine which is going to control it in the FA design that used PLC. Output point is going to be extended with 2-3 points in the state that cannot equip output unit in basic base any more. Then an extension base, a power supply, an extension cable and an output unit must be equipped particularly. Then a cost must be added very much. This paper propose the method which extended an output in a small quantity. We designed the expansion unit that received the points of output unit and decoded the signal and the program module that finally extended output points by encoding and decoding, and we confirmed his feasibility through a experiment.

A Study on Design of Offshore Meteorological Tower (해상기상탑 설계에 관한 연구)

  • Moon, Chae-Joo;Chang, Young-Hak;Park, Tae-Sik;Jeong, Moon-Seon;Joo, Hyo-Joon;Kwon, O-Soon;Kwag, Dae-Jin;Jeong, Gwon-Seong
    • Journal of the Korean Solar Energy Society
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    • v.34 no.2
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    • pp.60-65
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    • 2014
  • A meteorological(met) tower is the first structure installed during the planning stages of offshore wind farm. The purpose of this paper is to design the met tower with tripod bucket type support structure and to install the sensors. The support structure consist of a central steel shaft connected to three cylindrical steel suction buckets which is more cheaper than monopile or jacket type. And the remote wind condition sensors and marine monitoring equipment, including adcp, pressure type tide gauge, wave height sensors, and scour sensors, remote power supply are installed. The manufactured met tower constructed on sea area which is in front of Gasa island. All of functions of met tower showed normal operation conditions and the wind data got by remote data collection system successfully.

A Theoretical Study on the Feasibility of Long Distance Heat Transport Network Using Decomposition/Synthesis of Methanol (메탄올의 분해/합성 반응을 이용한 장거리 열수송 네트웤 구축 가능성에 대한 이론적 연구)

  • Jang, In-Sung;An, Ik-Kyoun;Han, Gui-Young;Moon, Seung-Hyun;Park, Sung-Youl;Park, Min-A;Lee, Hoon;Yoon, Seok-Mann
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 2007.11a
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    • pp.187-192
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    • 2007
  • A project is being implemented to develop the long distance energy transport technology using the chemical reactions. This project can be classified into three main research categories covering heat recovery reaction, long distance energy transport, and heat generation reaction. In this study, the methanol is selected as a system material since it shows several unique superior characteristics as follows: gaseous state of reactant and product, large heat of reaction, high yields of reaction at relatively low temperature, and also steady and economical supply. Furthermore, it is anticipated that the outcomes of this study can be widely applied to the related industries. A feasibility study was carried out to evaluate the economics of this technology which study was based on the following case: 10,000 households, 15km distance energy transportation, utilization of waste heat from power plant.

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Microfabrication of Submicron-size Hole on the Silicon Substrate using ICP etching

  • Lee, J.W.;Kim, J.W.;Jung, M.Y.;Kim, D.W.;Park, S.S.
    • Proceedings of the Korean Vacuum Society Conference
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    • 1999.07a
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    • pp.79-79
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    • 1999
  • The varous techniques for fabrication of si or metal tip as a field emission electron source have been reported due to great potential capabilities of flat panel display application. In this report, 240nm thermal oxide was initially grown at the p-type (100) (5-25 ohm-cm) 4 inch Si wafer and 310nm Si3N4 thin layer was deposited using low pressure chemical vapor deposition technique(LPCVD). The 2 micron size dot array was photolithographically patterned. The KOH anisotropic etching of the silicon substrate was utilized to provide V-groove formation. After formation of the V-groove shape, dry oxidation at 100$0^{\circ}C$ for 600 minutes was followed. In this procedure, the orientation dependent oxide growth was performed to have a etch-mask for dry etching. The thicknesses of the grown oxides on the (111) surface and on the (100) etch stop surface were found to be ~330nm and ~90nm, respectively. The reactive ion etching by 100 watt, 9 mtorr, 40 sccm Cl2 feed gas using inductively coupled plasma (ICP) system was performed in order to etch ~90nm SiO layer on the bottom of the etch stop and to etch the Si layer on the bottom. The 300 watt RF power was connected to the substrate in order to supply ~(-500)eV. The negative ion energy would enhance the directional anisotropic etching of the Cl2 RIE. After etching, remaining thickness of the oxide on the (111) was measured to be ~130nm by scanning electron microscopy.

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