• 전력전자학회논문지
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• 제5권2호
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• pp.154-162
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• 2000

본 논문에서는 3상 강압형 다이오드 정류기에서 출력전압의 저주파 리플 전압을 감소시키기 위한 새로운 제어기법을 제안한다. 제안한 펄스 주파수 변조 기법은 강압형 다이오드 정류기의 출력전압과 넓은 부하 범위에 대한 주 스위치의 영전류 스위칭을 보장하기 위해 적용된다. 본 논문에서 적용된 펄스 주파수 변조 기법은 일반적으로 입력전류의 낮은 고조파의 단위 역률의 장점을 지니고 있다. 또한 출력전압에서 보여진 저주파 리플전압을 감소시키기 위해 효과적으로 사용되어진다. 제안된 제어기법을 자세하게 설명하며 그 타당성을 검증하기 위해 시뮬레인션 및 실험을 통하여 검증한다.

• 전력전자학회논문지
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• 제19권6호
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• pp.488-493
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• 2014

This paper presents a carrier-based pulse-width modulation(PWM) method for reducing the common-mode voltage of a three-level four-leg converter. The idea of the proposed PWM method is intuitive and easy to be implemented in digital signal processor-based converter control systems. On the basis of the analysis of space-vector PWM(SVPWM) and sinusoidal PWM(SPWM) switching patterns, the fourth leg pole voltage of the three-phase converter called "f leg pole voltage" is manipulated to reduce the common-mode voltage. To synthesize f leg pole voltage for the suppression of the common-mode voltage, positive and negative pole voltage references of f leg are calculated. An offset voltage is also deduced to prevent the distortion of a, b, and c phase voltages. The feasibility of the proposed PWM method is verified by simulation and experimental results. The common-mode voltage of the proposed PWM method in peak-to-peak value is 33% in comparison with that of the conventional SVPWM method. The transition number of the common-mode voltage is also reduced to 25%.

• 한국통신학회논문지
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• 제37권6B호
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• pp.423-432
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• 2012

솔라셀의 동작 상태와 센서 MAC 프로토콜의 Active 및 Sleep 동작 모드를 고려하여 충전배터리와 센서통신장치의 입력 전원을 제어하는 회로를 설계한다. 솔라셀과 재충전 배터리를 단순 조합하는 센서통신장치는 햇빛이 없는 시간이 장기간 지속될 때 배터리 소모가 많아서 작동을 멈추게 된다. 일반적으로 센서 MAC 프로토콜은 전력소모를 줄이기 위하여 짧은 Active모드와 전력 소모가 거의 없는 긴 Sleep모드를 반복한다. 이러한 특성을 고려하여, 햇빛이 충분하고 Sleep모드이면 배터리를 충전하고 햇빛이 불충분하고 Active모드이면 배터리 전력을 사용하도록 설계함으로써 배터리 지속 시간을 크게 향상시켰다. 또한, 센서통신장치는 솔라셀의 출력전력값의 크기에 따라서 솔라셀과 배터리 사이에서 입력 전원을 스위칭 하도록 하였다. 스위칭 도중에 일시적 전원 차단으로 인한 마이크로프로세서의 리셋을 방지하기 위하여 커패시터를 사용하였다. 또한, 커패시터는 Sleep모드에서 전원을 공급한다. 실험을 통하여 본 센서통신장치가 장기간의 햇빛이 없는 경우에도 안정적으로 작동한다는 것을 입증하였다.

• The Plant Pathology Journal
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• 제31권2호
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• pp.108-114
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• 2015

Curvularia lunata is an important maize foliar fungal pathogen that distributes widely in maize growing area in China, and several key pathogenic factors have been isolated. An yeast two-hybrid (Y2H) library is a very useful platform to further unravel novel pathogenic factors in C. lunata. To construct a high-quality full length-expression cDNA library from the C. lunata for application to pathogenesis-related protein-protein interaction screening, total RNA was extracted. The SMART (Switching Mechanism At 5' end of the RNA Transcript) technique was used for cDNA synthesis. Double-stranded cDNA was ligated into the pGADT7-Rec vector with Herring Testes Carrier DNA using homologous recombination method. The ligation mixture was transformed into competent yeast AH109 cells to construct the primary cDNA library. Eventually, a high qualitative library was successfully established according to an evaluation on quality. The transformation efficiency was about $6.39{\times}10^5$ transformants/$3{\mu}g$ pGADT7-Rec. The titer of the primary cDNA library was $2.5{\times}10^8cfu/mL$. The numbers for the cDNA library was $2.46{\times}10^5$. Randomly picked clones show that the recombination rate was 88.24%. Gel electrophoresis results indicated that the fragments ranged from 0.4 kb to 3.0 kb. Melanin synthesis protein Brn1 (1,3,8-hydroxynaphthalene reductase) was used as a "bait" to test the sufficiency of the Y2H library. As a result, a cDNA clone encoding VelB protein that was known to be involved in the regulation of diverse cellular processes, including control of secondary metabolism containing melanin and toxin production in many filamentous fungi was identified. Further study on the exact role of the VelB gene is underway.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.132-132
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• 2011

For the programming volume of PRAM, Ge2Sb2Te5(GST) thin films have been dominantly used and prepared by physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD). Among these methods, ALD is particularly considered as the most promising technique for the integration of PRAM because the ALD offers a superior conformality to PVD and CVD methods and a digital thickness control precisely to the atomic level since the film is deposited one atomic layer at a time. Meanwhile, although the IST has been already known as an optical data storage material, recently, it is known that the IST benefits multistate switching behavior, meaning that the IST-PRAM can be used for mutli-level coding, which is quite different and unique performance compared with the GST-PRAM. Therefore, it is necessary to investigate a possibility of the IST materials for the application of PRAM. So far there are many attempts to deposit the IST with MOCVD and PVD. However, it has not been reported that the IST can be deposited with the ALD method since the ALD reaction mechanism of metal organic precursors and the deposition parameters related with the ALD window are rarely known. Therefore, the main aim of this work is to demonstrate the ALD process for IST films with various precursors and the conformal filling of a nano size programming volume structure with the ALD?IST film for the integration. InSbTe (IST) thin films were deposited by ALD method with different precursors and deposition parameters and demonstrated conformal filling of the nano size programmable volume of cell structure for the integration of phase change random access memory (PRAM). The deposition rate and incubation time are 1.98 A/cycle and 25 cycle, respectively. The complete filling of nano size volume will be useful to fabricate the bottom contact type PRAM.

• International Journal of Automotive Technology
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• 제4권2호
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• pp.65-75
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• 2003

A HEV evaluation program, funded by ADEME, was carried out by a group of Laboratories of different specialties in order to evaluate and compare consumption, emission and component technologies of the three first HEVs put on the market (Toyota Prius, Nissan Tino and Honda Insight). This paper presents the results obtained until now. These results show good consumption and emission performance of the tested vehicles compared to conventional ones. The energy management seems to be globally the same for the three vehicles excepting for cold stans where the Insight allows a very earlier stop of the engine compared to the Tino and especially to the Prius. A mapping of the engine consumption of the Prius and the Insight was performed in order to furnish data for the simulation models. The Permanent Magnet motors of the Prius and Tino have different number of pair poles and then different emf at a given speed. The low emf values of the Prius allow operation at high speed with less field weakening control than for the Tino. The inverters of the Prius and the Tino, controlled by a PWM at respectively 5 kHz and 7 kHz switching frequency, are made of IGBTs with high commutation performances.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2777-2783
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• 2015

전력 피크 감소는 전력 공급자 뿐 아니라 사용자에게도 점점 중요한 기술이 되고 있다. 전기 부하 스케줄링은 기기의 주기적 작동 시간을 여러 개의 시간 조각들로 분리하고 여러 기기들에 대해 작동 시간 조각들을 통합적으로 교차 배치하여 전력 피크를 줄이는 기법이다. 본 논문에서는 부하 스케줄링 알고리즘인 EDF, LSF, TCBM, lazy 스케줄러의 성능을 분석하고 개선 방안을 제시한다. 분석을 위해 스케줄링 정책들을 분산제어 시뮬레이션 환경에서 구현하고, 실제 전력 사용 데이터를 이용한 광범위한 실험을 통해 전력 편차, 스위칭 횟수, 온도 범위 위반 비율 등의 관점에서 스케줄링 정책별 성능 특성을 논한다. 또한, 과도한 스위칭 방지를 위해 제한적 선점 기능을 제안하고 그 효과를 입증한다. 실험결과, 스케줄러 용량을 실제 전력 요구에 맞춰 설정하면 성능이 극대화됨을 확인하였으며, 스케줄링을 통해 150W 보다 큰 전력편차를 가지는 비율이 원래 21.5%에서 3.2%까지 감소함을 알 수 있었다.

• 조명전기설비학회논문지
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• 제16권2호
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• pp.121-129
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• 2002

본 논문에서는 효과적인 접지그리드 설치기법에 대하여 기술하였으며, 낙뢰나 지락고장서지, 개폐서지 등으로 부터 인체의 감전보호나 컴퓨터를 비롯한 전기·전자기기의 보호를 위한 접지그리드의 시설 및 배치방법에 따른 실험적인 평가를 수행하였다. 접지그리드의 배치에 따른 대지표면전위경도의 분석과 위험전압으로 작용하는 대지 표면전위상승의 억제에 주안점을 두고 실험용 모델접지전극을 시설한 후 임 펄스전류를 인가하였다. 기존의 등간격 접지그리드의 결점을 보완하기 위해 접지그리드에 경사를 가지는 보조접지그리드를 시설하였으며, 보조접지그리드를 시설한 접지시스템에서는 인체나 전기·전자기기에 위험전압으로 작용하는 대지표면전위경도를 최대 50%이상 완화시키는 효과를 얻었다.

• Journal of Communications and Networks
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• 제9권4호
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• pp.511-523
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• 2007

In broadband convergence network(BcN), heterogeneous broadband wired & wireless subnetworks and various terminal equipments will be interconnected. In order to provide end-to-end realtime multimedia services on such heterogeneous networking environment, as a result, two major problems should be resolved: i) Multimedia session establishment & negotiation that adjusts the differences in the capability of multimedia data processing at the end terminal nodes, ii) quality of service(QoS)-guaranteed connection establishment or resource reservation with connection admission control(CAC) in each heterogeneous subnetworks along the path. The session layer signaling(e.g., SIP/SDP) should be extended for QoS negotiation, and must be tightly cooperating with network layer signaling or resource reservation with CAC function. In this paper we propose a session and connection management architecture for the QoS-guaranteed realtime multimedia service provisioning on BcN, with Q-SIP/SDP, resource reservation protocol with traffic engineering extension, and CAC functions. The detailed interaction scenario and related algorithms for QoS-guaranteed realtime multimedia session, resource reservation and connection establishment are explained and analyzed. From the experimental implementation of the proposed scheme on a small scale BcN testbed, we verified that the proposed architecture is applicable for the realtime multimedia service provisioning. We analyze the network performance and QoS parameters in detail.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.216-218
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• 2001

The transformer role is very important in power system operation and control; also its price is very expensive. Therefore many kinds of the efforts for transformer protection have been executed. So for as, current differential relay(87) has been mainly used for transformer protection. But current differential relaying method has several troubles as followings. Differential current can be occurred by transformers inrush current between winding1 and winding2 of transformer when transformer is initially energized. Also harmonic restrained element used in current differential relaying method is one of the causes of relays mal-operation because recently harmonics in power system gradually increase by power switching devices(SVC, FACTS, DSC, etc). Therefore many kinds of effort have been executed to solve the trouble of current differential relay and one of them is method using ratio of increment of flux linkages(RIFL) of the primary and secondary windings. This paper introduces a novel protective relay for power transformers using RIFL of the primary and secondary windings. Novel protective relay successfully discriminates between transformer internal faults and normal operation conditions including inrush and this paper includes real time test results using RTDS(Real Time Digital Simulator) for novel protective relay. A novel protective relay was designed using the TMS320C32 digital signal processor and consisted of DSP module. A/D converter module, DI/DO module, MMI interface module and LCD display module and developed by Xelpower co., Ltd.