• Title/Summary/Keyword: power conditioner

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3상 인버터 시스템에서 주파수 특성을 고려한 필름 콘덴서의 DC-link 적용 방법에 관한 연구 (The study on DC-link Film Capacitor in 3 Phase Inverter System for the Consideration of Frequency Response)

  • 박현수
    • 한국산학기술학회논문지
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    • 제19권4호
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    • pp.117-122
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    • 2018
  • 대용량 3상 시스템 에어컨은 최근 들어 소비 전력 저감을 위해 인버터 회로를 포함하고 있다. 인버터 회로는 교류를 다이오드를 통해 정류하고 DC-link 전원부 콘덴서에 의해 평활된 직류를 사용한다. 이 때 평활에 사용되는 DC-link 전원부 콘덴서는 전압 리플, 전류 리플 조건을 만족하기 위해 전해 콘덴서가 일반적으로 사용된다. 콘덴서의 용량을 줄이게 되면 회로부의 크기 및 무게, 비용을 줄일 수 있게 된다. 본 논문에서는 최소점 추정 PPL(Phase Locked Loop) 위상 제어와 평균 전압 d축 전류제어 기법을 조합하여 입력 리플 전류를 약 90% 저감하는 알고리즘을 제안한다. 입력 리플 전류의 감소로 인해 DC-link 콘덴서의 전류 리플도 감소하므로 콘덴서의 용량을 줄일 수 있지만 전해 콘덴서의 경우 등가 직렬 저항(ESR : Equivalent Series Resistance)이 크기 때문에 발열로 인한 수명이 한계를 가진다. 본 논문에서는 전해 콘덴서 대신 DC-link 단에 전류 리플을 고려한 필름 콘덴서를 선정하는 방법을 제안한다. 필름 콘데서의 정전 용량 선정, 내압 선정, RMS(Root Mean Square) 전류 용량, RMS 전류 주파수 해석을 고려해 콘덴서의 용량을 선정할 경우 1680uF의 전해 콘덴서를 20uF로 용량을 낮추어 설계함으로써 전원부 콘덴서의 크기 및 무게, 비용을 줄였으며 전동기 구동을 통해 동작을 확인하였다.

자동차 풀리 제조공정의 불량률 감소를 위한 데이터 웨어하우스 구조 설계 (Design of Data Warehouse System for Reducing Defect Rate in Automotive Pulley Manufacturing Process)

  • 이규봉;김보현;오봉훈;주인식;장재덕
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.133-138
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    • 2005
  • Automotive pulleys play a key role in driving the cooling pump, oil pump, air-conditioner and so on by using an engine power. Researches on design processes and technologies of the pulleys can be found in many literatures. On the other hand, the areas related to manufacturing processes of the pulleys have been treated negligently. Vast data extracted from various information systems are transformed, integrated, and summarized to become a special database for helping users make a decision. The database, namely the data warehouse has been popularly used in the marketing and customer management of enterprises and recently applied to improve the design and manufacturing processes. In this study the manufacturing process of pulleys were analyzed through the intensive investigation of shop-floors and the interviews with workers and managers. The defects generated during a manufacturing process were categorized in a few types and the causes of defects examined for extracting the dominant parameters in the setup process for producing pulleys. As the first step to construct the data warehouse for the manufacturing processes of pulleys, authors proposed its architecture focused on the reduction of defect rate during the setup process.

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가전제품 소음등급 기준설정에 관한 연구 (Study on Establishment of the Noise Grade Criteria for Household Appliances)

  • 박형규;이재원;이우석;한진석;구진회
    • 한국소음진동공학회논문집
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    • 제22권12호
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    • pp.1237-1242
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    • 2012
  • No matter how low it might be, noise from home appliances in indoor environment cause displeasure for residents as it is produced nearby. Electronic goods including vacuum cleaner and washing machine generate high frequency noise, which interrupts TV-watching or conversations and cause noises between floors in apartment houses. In particular, refrigerators make constant noise late at night, hampering the study for exams and causing sleeplessness. Korea, despite the government's efforts to promote low-noise goods based on the noise test by corporation, there is a lack of standardization in the test method, test condition and measuring equipments. This is a major reason that lowers the reliability of low-noise products. At present, low-noise home appliances are certified with eco labeling in the nation but, only 7 brands of refrigerators, 4 brands of washing machines and 97 brands of air-conditioners obtained certification as of august, 2011. In addition, none of Kimchi-refrigerator and vacuum cleaner brands were approved as low-noise home appliances. This shows Korea's relatively underdeveloped market for low-noise products, which, in part, is because of the difficulties companies face in being certified with eco labeling as they should satisfy various requirements such as power-saving and eco-friendly design besides low-noise features. As a result, low-noise labeling for home appliances should be established for the revised noise and vibration management law and the study was carried out to establish low-noise labeling system for major noise sources including vacuum cleaner, washing machine, air-conditioner and refrigerator.

직렬아크현상의 검출기술 및 장치 (Detection Technique and Device of Series Arcing Phenomena)

  • 지홍근;정광석;박대원;길경석;서동환;류길수
    • Journal of Advanced Marine Engineering and Technology
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    • 제34권2호
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    • pp.332-338
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    • 2010
  • 전력계통에서 아크현상이 원인이 되는 전기화재는 전기제품의 사용증가에 따라 급증하고 있으나, 이들 사고를 방지할 수 있는 확립된 방법은 없다. 이들 배경에서 본 논문은 공기조화기에서 직렬아크 검출 기술과 장치에 대한 실험적 결과에 대해 기술하였다. 공기조화기의 불완전한 접속부에서 발생하는 직렬아크를 모의하고, 주파수 스펙트럼을 FFT로 분석한 결과, 190 kHz~250 kHz와 900 kHz~1.6 MHz 에 존재함을 알 수 있었다. 저역차단주파수가 170 kHz이며 60 Hz를 176 dB까지 감쇄시킬 수 있는 아크검출 및 파형정형 회로를 설계하였다. 또한 스위치 조작, 인버터 운전 및 서지 등에 의해 발생하는 노이즈로부터 직렬아크신호를 분리할 수 있는 알고리즘을 제안하였다. 적용실험은 UL1699에 규정 되어있는 아크발생장치를 이용하여 여러 형태의 공기조화기에서 수행되었으며, 99 %이상 검출능력을 나타내었다.

고밀도 데이터센터의 열환경제어를 위한 수치해석 (Numerical Analysis of Thermal Environment Control in High-Density Data Center)

  • 권오경;김현중;차동안
    • 대한기계학회논문집B
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    • 제36권8호
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    • pp.821-828
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    • 2012
  • CPU의 발열량 증가는 서버를 통과하는 배출공기와 유입공기와의 상당한 온도차를 발생시키고 이로 인해 배출공기의 재순환 현상과 유입공기의 바이패스 현상이 발생한다. 이는 데이터센터 냉각시스템의 효율저하를 발생시킨다. 따라서 CRAC의 제어를 통해 유입공기와 배출공기를 분리하는 것이 데이터센터 냉각시스템의 중요한 목표이다. 본 연구에서는 CFD 해석 코드인 ICEPAK을 이용하여 데이터센터에 대한 수치해석을 진행하였다. 실내부로 유입되는 공기유량의 변화에 따른 CPU의 온도와 실 전체의 온도분포를 분석하였다. 이를 통해 CPU의 발열량에 따른 최적 유입유량을 선정하였다. CPU 발열량이 100, 120, 140 W인 경우 유입유량이 $0.15m^3/s$인 지점에서 발열제거와 온도분배가 가장 잘 이루어졌다. RTI 성능지표를 이용하여 해석결과를 검증하였고 RTI 값이 81인 경우 가장 안정적인 결과를 보였다.

천연가스 개조 승용차에 대한 실험적 연구(1) - 연비, 배기 및 주행 성능 (Experimental Study on Natural Gas Conversion Vehicle(1) - Fuel Economy, Emission and Roadability)

  • 김형구;김인옥;엄인용
    • 한국자동차공학회논문집
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    • 제23권4호
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    • pp.410-419
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    • 2015
  • In this study, the roadability, fuel economy and emission characteristics were evaluated for a natural gas converted vehicle. The results are as follows; Not only the shortage of power was observed in stall test, but also large deterioration of acceleration performance was exposed in roadability. Compared to the original LPG system, the acceleration is 76% in start acceleration and 45 ~ 65% in overtaking acceleration, especially the decline became larger when air conditioner is at work. Furthermore, because the mapping data, which controls the injection depending on driving condition, do not match up with injection system, the failure of air-fuel ratio feedback control occurs resulting from the large gap between the required and the really supplied amount of fuel. This failure cause the exhaust gas to emit without catalytic conversion and the fuel economy based on the fuel heat value to get worse 22% in the mode test and 16% in road test respectively. In addition, the existing injection system does not secure enough fuel at the starting so that it may lead to the fail of clod start, the deterioration of hot start and inharmonic of engine at the idle after start.

계측시스템을 활용한 틸팅열차 추진장치 특성 연구 (A Study on TTX Traction Characteristics using Measurement System)

  • 한영재;이수길;박춘수;한성호;이준석;정권일
    • 한국전기전자재료학회논문지
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    • 제20권12호
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    • pp.1093-1098
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    • 2007
  • Tilting trains are currently in operation in 13 countries around the world. With the advances in tilting technology, verification of economic efficiency, and changes in economic situations, the introduction of tilting trains will rapidly spread across the globe. The measurement system is composed of the industrial computers installed in the console and the measurement racks mounted on each car. It is utilized to accumulate the data by the communication card and the optical cable. The optical cable and power cable are coupled at the connector located in joint of train to make easy to disconnect car each other. The signal conditioner is designed to choose and to extend the channel for each sensor readily. The sensor measurement rack has adopted as decentralization method. It is installed in each car to minimize the cable length. In also, it is manufactured based on 19"rack and covered to protect the cable. In this study, the programs for measurement and analysis were also developed to understand the traction system characteristics of TTX. Using this measurement system, we studied that acceleration test, re-powering test, and gradually powering test. The acceleration performance of TTX is 1.735 km/h/s, and it is inner standard value. The notch test result from 1 to 7 steps, DC link voltage is under standard value, and the output electric current of inverter is controlled normally. From the test results, we saw the performances of the traction systems are normal.

하계 공동주택 하이브리드 환기시스템 적용에 따른 실내공기 및 열 환경 평가 (Analysis of Indoor Air & thermal environment with Hybrid Ventilation system during summer)

  • 김상진;김은수;김태연;이승복
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2006년도 하계학술발표대회 논문집
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    • pp.387-392
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    • 2006
  • The recent on indoor air problem has led to many studies on the methods and effects of ventilation for better indoor air quality. Although natural ventilation is the most effective and energy-saving method in residental housings, the small size of openable window has been a problem in high-rise residential buildings to ventilate only through natural ventilation. Consequently, the installation of mechanical ventilation system has been a requirement in residential buildings, and has caused other problems such as increase of energy consumption and SBS. Hybrid ventilation which uses forces of both natural and mechanical power has been introduced to solve the problem of increase in energy consumption with natural ventilation. In this paper, two types of hybrid ventilation systems in residential building were introduced. One type was with natural ventilation through vent grille in the window, and another type was with natural ventilation through ceiling duct while both types used mechanical ventilation system with the outlets. The indoor temperature distribution and pollution density distribution in summer while operating the ceiling air conditioner were analyzed through CFD simulation. In this paper, the optimal location of diffusers to achieve thermal comfort would be proposed.

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설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제26권12호
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

라즈베리 파이를 이용한 실내관리 시스템 (A Indoor Management System using Raspberry Pi)

  • 정수;이종진;정원기
    • 한국산학기술학회논문지
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    • 제17권9호
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    • pp.745-752
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    • 2016
  • 모든 사물들이 인터넷에 연결되는 사물 인터넷 시대에 즈음하여 본 논문에서는 라즈베리파이와 지그비를 이용하여 실내의 LED 조명등과 멀티탭을 on/off 하고 조명등의 밝기와 출입문의 전자 도어락을 스마트폰으로 원격 제어하는 시스템을 제안한다. 라즈베리파이에 적외선 송신 모듈을 연결하여 리모트컨트롤이 가능한 에어컨 등의 가전제품을 스마트폰 어플로 제어했으며 실내의 영상, 실내온도, 조도 등을 모니터링 했다. 리모트컨트롤이 가능한 모든 가전제품들을 원격 제어하기 위해서는 IR 송신코드를 알아내어야 하는데 AVR 마이크로컨트롤러를 이용해서 IR 송신코드를 알아내는 방법을 제안했다. 상용의 사무실용 도어락을 개조하여 원격으로 개폐하는 방법을 제안했다. LED 조명의 밝기는 ATmega88로 PWM 신호를 발생시켜서 0에서 10 레벨까지 컨트롤했고 멀티탭의 제어는 ATmega32와 포토커플러, TRIAC를 사용하였다. 측정된 온도 및 조도는 Tiny44A를 사용하여 A/D 변환되고 SPI 통신으로 라즈베리파이에게 송신된다. 카메라는 라즈베리파이의 CSI(Camera Serial Interface) 헤드에 연결하였다. 스마트 멀티탭은 일정시간 동안 on 시킬 수 있고 미래시점에 on이 되도록 예약할 수 있다. 대기전력을 줄이기 위해서는 수동으로 멀티탭의 콘센트를 뽑거나 스위치을 꺼면 되지만 스위치를 꺼지 않고 외출한 경우에도 스마트폰으로 원격 제어하여 스위치를 꺼면 대기전력을 줄이는데 많은 도움이 될 것이다.