• 전자공학회논문지 IE
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• 제44권1호
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• pp.1-5
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• 2007

본 논문에서는 FFL에 대한 기초 방전특성의 일부분으로 인가전압을 정현파와 구형파로 변화시켜 V-Q Lissjous 도형을 이용하여 FFL의 방전형태를 분석하고, 인가전압의 듀티비(duty ratio)의 면화에 의한 radiation transition에 대하여 고찰하였다. FFL을 정현파와 펄스파을 이용하였고, 절연층으로 둘러 쌓여 있는 전극을 갖는 FFL의 방전 특성을 V-Q 리사쥬 도형을 이용하여 방전 특성을 고찰하였다. FFL은 펄스파로 구동하였을 때 방전 전류는 전압의 상승 순간에 방전 전류가 흐른다. 듀티비가 증가하면 준안정 준위의 Xe 원자들은 증가하며 172nm의 자외선 방사량이 증가하고 있음을 확인할 수 있었다.

• Journal of Power Electronics
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• 제16권3호
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• pp.872-882
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• 2016

A novel pseudo-continuous conduction mode (PCCM) voltage-fed single-stage power factor correction (PFC) full-bridge battery charger is proposed in this paper. By connecting a freewheeling transistor in parallel with an input inductor, the PFC cell can operate in the PCCM with a constant duty ratio. Thus, the dc/dc stage can be designed using this constant duty ratio and the restriction on the duty ratio of the PFC cell is eliminated. As a result, the input current distortion is less and the dc bus voltage becomes controllable over the wide output power range of the battery charger. Moreover, the operation principle of the dc/dc stage is designed to be similar to that of a conventional phase-shifted full-bridge converter. Therefore, it is easy to implement. In this paper, the operation of the new converter is explained, and the design considerations of the controller and key parameters are presented. Simulation and experimental results obtained from a 1 kW prototype are given to confirm the operation of the proposed converter.

• Journal of Power Electronics
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• 제18권6호
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• pp.1642-1649
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• 2018

A single-stage flyback LED AC-DC converter based on primary-side control under constant current mode is proposed in this study. The proposed converter features low total harmonic distortion (THD) and high power factor (PF). It also consists of a zero-crossing distortion compensation circuit and a variable duty ratio control compensation circuit to deal with the line current distortions caused by fixed duty ratio control. The system model and layout are built in Simplis and Cadence, respectively. The feasibility and performance of the proposed circuit is verified by designing and fabricating an IC controller in the HHNEC $0.35{\mu}m$ 5 V/40 V HVCMOS process. Experimental results show that the PF can reach a level in the range of 0.985-0.9965. Moreover, the average THD of the entire system is approximately 10%, with the minimum being 6.305%, as the input line voltage changes from 85 VAC to 265 VAC.

• 대한전자공학회논문지SD
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• 제49권7호
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• pp.1-9
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• 2012

기존의 LED 패키지가 갖는 온도에 따른 광 특성 변화 문제를 해결하기 위하여 온도센서가 집적된 LED 패키지 시스템을 제안하였다. 패키지의 온도를 실시간으로 측정하기 위하여 정확도가 우수하며 온도에 따른 저항의 변화가 선형적인 특징을 갖는 온도센서(RTD 형)를 설계하였으며, 장기간의 안정성을 보장하기 위하여 안정된 박막의 증착조건을 결정하고 이를 바탕으로 $1.560{\Omega}/^{\circ}C$의 민감도를 갖는 온도센서를 패키지 내부에 제작하였다. 제작된 패키지를 이용하여 온도에 무관하게 일정한 광량을 나타내는 시스템의 구현을 위하여 변환 회로부와 제어 회로부를 제작하고 이들을 결합함으로써, 패키지의 온도 변화에 따라 PWM duty ratio의 변화를 통해 광 출력을 보상해 주는 시스템을 제안하고 제작하였다. LED의 동작온도인 $0^{\circ}C$에서 $140^{\circ}C$ 범위에서 PWM duty ratio를 관측한 결과 제안했던 일정한 광량을 위한 PWM duty ratio에 매우 근접한 출력 신호를 발생시키는 것을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.145-147
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• 2005

This paper presents a methodology for satisfying the thermal comfort of Indoor environment and reducing the summer peak demand power by minimizing the power consumption for an Air-conditioner within a space. KEPCO(Korea Electric Power Corporation) use the fixed duty cycle control method regardless of the indoor thermal environment. This method has disadvantages that energy saying depends on the set-point value of the Air-Conditioner and DLC has no net effects on Air-conditioners if the appliance has a lower operating cycle than the fixed duty cycle. A variable duty cycle estimates the PMV(Predict Mean Vote) at the next step with a predicted temperature and humidity coming from the back propagation neural network model. It is possible to reduce the energy consumption by maintaining the Air-conditioner's OFF state when the PMV lies in the thermal comfort range. The proposed methodology uses the historical real data of Sep. 7th, 2001 from a classroom in seoul to verify the effectiveness of the variable duty cycle method comparing with fixed duty cycle. The result shows that the variable duty cycle reduces the peak demand to 2.6times more than fixed duty cycle and increases the load control ratio by 8% more. Based on the variable duty cycle control algorithm, the effectiveness of DLC is much more improved as compared with the fixed duty cycle.

• 한국대기환경학회지
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• 제15권4호
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• pp.457-461
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• 1999

Recently, increasing usage of diesel vehicle, many countries try to reduce the pollutant materials by emission regulation standard. Particularly, in our country, the supplement ratio of diesel vehicle is high, and air pollution by particulate matter(PM) is very serious. So, in theoretical study wer analyzed the formation principle of gaseous emission and PM, the characteristics of CVS-75 mode. In experimental study, we tested exhaust gas reduction of emission and PM, the characteristics of CVS-75 mode. In experimental study, we tested exhaust gas reduction of disel oxidation catalyst(DOC) by CVS-75 mode in light duty diesel vehicle. In case of an automobiletest with the 2,956cc diesel engine which DOC was equipped, CVS-75 mode which is similar to driving conditions on the road was chosen as the restrictive mode of light duty diesel automobile in our country. According to the Pt, the reduction rate of exhaust emission was estimated with using 0.1% high sulfur fuel and 0.05% low sulfur fuel.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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• pp.103-106
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• 2001

In this paper, a soft switching half-bridge converter using secondary switches for output control and conduction loss reduction is proposed. The conventional half-bridge converter must be fixed on duty cycle for soft switching. The proposed converter was consisted of two added switches in series of the secondary rectifier diodes. The main switches with constant duty cycle are operated ZVS. The secondary switches are operated ZV-ZCS. Especially, the primary switches were fixed duty cycle for maximum voltage conversion ratio. Output of converter is controlled by duty cycle or phase-shifted time of secondary switches. The conduction loss of the proposed converter can be reduced by the secondary switches. The operation characteristic, analysis, simulation and experimental results of the proposed converter are presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.155.2-155
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• 2001

A heavy duty power manipulator consisting of high reduction ratio joints is usually used in heavy duty tasks. When the heavy duty power manipulator is used as the slave manipulator in the teleoperated bilateral control system, the position control performance of the slave manipulator and the system stability tend to deteriorate due to the windup phenomenon caused by actuator saturation. KAERI has developed a teleoperated bilateral control system for the study of the remote handling of a spent fuel mockup bundle, which has an enhanced bilateral control algorithm improving the position tracking performance of the slave manipulator while compensating for the windup phenomenon. In this paper, the developed bilateral control system ...

• 한국항행학회논문지
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• 제14권6호
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• pp.831-837
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• 2010

광 시간 분할 다중/파장 분할 다중 (OTDM/WDM; optical time division multiplexing/wavelength division multiplexing) 전송 시스템의 구현을 위한 40 Gbps RZ 형식의 최적 조건을 충격 계수 (duty cycle)와 소광비 (ER; extinction ratio)에 따른 성능 분석과 비교를 통해 도출하였다. 광전송 링크에는 광섬유의 색 분산과 비선형에 의한 신호 왜곡을 보상하기 위해 광 위상 공액기 (OPC; optical phase conjugator)와 inline 분산 제어 (DM; dispersion management)가 적용되었다. ER에 따른 시스템 성능 변화의 영향이 적으면서 동시에 OTDM에 의한 160 Gbps 신호로의 다중화에 적합한 충격 계수는 0.25이라는 것을 확인하였다. 또한 DM의 적용에 있어 중계 거리 당 잉여 분산 (RDPS; residual dispersion per span)을 크게 할수록 동일한 전체 잉여 분산 (NRD; net residual dispersion)에 의해 결정되는 RZ 형식의 성능 개선 정도를 증가시킬 수 있는 것을 알 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제7권5호
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• pp.714-723
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• 2012

A new Z-source inverter (ZSI) topology is developed to improve voltage boost ability. The proposed topology is modified from the switched inductor topology by adding some more inductors and diodes into inductor branch to the conventional Z-source network. The modulation methods developed for the conventional ZSI can be easily utilized in the proposed ZSI. The proposed ZSI has an ability to obtain a higher voltage boost ratio compared with the conventional ZSI under the same shoot-through duty ratio. Since a smaller shoot-through duty ratio is required for high voltage boost, the proposed ZSI is able to reduce the voltage stress on Z-source capacitor and inverter-bridge. Theoretical analysis and operating principle of the proposed topology are explicitly described. In addition, the design guideline of the proposed Z-source network as well as the PWM control method to achieve the desired voltage boost factor is also analyzed in detail. The improved performances are validated by both simulation and experiment.