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직류가선전압 모의장치를 적용한 지하철용 회생인버터 시스템
지용혁(Ji Young-Hyok),조기현(Cho Ki-Hyun),장수진(Jang Su-Jin),원충연(Won Chung-Yuen),김용기(Kim Yong-Ki) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-
In this paper, a unified regenerative inverter system for railway with DC line voltage simulator is proposed. In order to determine the operation characteristics of the regenerative inverter, the DC line voltage simulator is proposed. The DC line voltage simulator, which is based on the AC-DC PWM converter, varies the DC voltage according to the fluctuating voltage which is measured in the actual DC line. The suitable operating point of the regenerative inverter can be estimated from the simulation result. The regenerative inverter operates two modes. When the DC line voltage exceed the operating point, already set up, it works as regenerative inverter to return the excessive power of DC line to the grid. When the DC line voltage is under the operating point, it works as active power filter to compensate harmonic currents. In this paper, the control algorithm of the DC line voltage simulator and that of the regenerative inverter is proposed.
중성선 영상 고조파 전류 저감을 위한 하이브리드 전력 필터
지용혁(Young-Hyok Ji),박상훈(Sang-Hoon Park),김재형(Jae-Hyung Kim),원충연(Chung-Yuen Won),송상훈(Sang-Hoon Song) 전력전자학회 2008 전력전자학술대회 논문집 Vol.- No.-
According to the development of power switching device technology, the power conversion system is used from the small electric power units to the large industrial instruments. These instruments are operated as harmonic sources in the grid and the harmonics cause zero sequence harmonics in the neutral line. To reduce zero sequence harmonics, the zigzag transformer is used conventionally. But the zigzag transformer can reduce only 60∼70% of harmonics. In this paper, hybrid power filter for zero sequence harmonics reduction and the harmonic detection method are proposed.
김영호(Young-Ho Kim),지용혁(Young-Hyok Ji),김재형(Jae-Hyung Kim),원충연(Chung-Yuen Won),김영렬(Young-Real Kim) 한국조명·전기설비학회 2008 한국조명·전기설비학회 학술대회논문집 Vol.2008 No.5월
In this paper, the battery charging device using DMFC(Direct Methanol Fuel Cell) for electric bicycle is proposed. In the proposed system, phase-shift full-bridge converter is used as a battery charger by boosting the 12V DMFC output voltage up to 36V. By using the phase-shift technique, the ringing of the transformer is reduced and the efficiency of the converter can be improved. The operation modes of proposed phase-shift full-bridge converter is analyzed and verified by the simulation and the experimental results.
태양전지 어레이 음영 변화에 따른 손실 보상을 위한 최대전력점 추종 기법
정훈영(Hoon-young Jung),지용혁(Young-hyok Ji),정두용(Doo-yong Jung),이수원(Su-Won Lee),원충연(Chung-Yuen Won) 한국조명·전기설비학회 2009 한국조명·전기설비학회 학술대회논문집 Vol.2009 No.5월
Under partial shading condition, the multiple local maxima can be existed on the output characteristics of PV array. In case of the conventional MPPTs (i.e, P&O or IncCond), the failure of maximum power point tracking could be occurred under partial shading condition(PSC). The problems are deduced by the analysis of conventional MPPTs. In this papar, a real maximum rower point tracking for PV array under partially shaded condition is proposed. And proposed MPPT is analyzed by case study. It is confirmed by simulation results that the proposed MPPT can track the real MPP under partial shading condition.
정훈영(Hoon-Young Jung),지용혁(Young-Hyok Ji),김재형(Jae-Hyung Kim),이수원(Su-Won Lee),원충연(Chung-Yuen Won),김진욱,Byoung-Kuk Lee 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.2
A digital grid synchronization technique is needed for distributed generation system to make output current sinusoidal even if the grid voltage is distorted by harmonics. In this paper, a digital grid synchronization technique based on adaptive notch filter is proposed. The analysis of proposed technique is performed through the consideration of grid synchronization technique based on PLL and FLL, and the validity of the proposed method was confirmed by simulation results..
김재형(Jae-Hyung Kim),지용혁(Young-Hyok Ji),원충연(Chung-Yuen Won),정용채(Yong-Chae Jung) 전력전자학회 2008 전력전자학술대회 논문집 Vol.- No.-
In this paper, novel phase angle following algorithm for the single phase grid-connected inverter is proposed. Gird-connected inverter needs phase angle detection for synchronization grid voltage with the inverter output. In case of single phase grid-connected inverter, zero crossing detection and virtual 2-phase PLL using digital all pass filter or digital low pass filter are used conventionally. But these methods have a weakness for harmonics, noises and ripples. The proposed method of PLL achieve DFT(Discrete Fourier Transform) using Goertzel algorithm. It can extract fundamental voltage of grid. As a results, it can obtain phase angle using digital all pass filter without effect of harmonics, noises and ripples. Simulation results are presented to demonstrate the effectiveness of the proposed algorithm.
인터리브드 소프트 스위칭 부스트 컨버터의 입출력 리플 분석
정두용(Doo-Yong Jung),지용혁(Young-Hyok Ji),김영렬(Young-Real Kim),정용채(Yong-Chae Jung),원충연(Chung-Yuen Won) 전력전자학회 2012 전력전자학회 논문지 Vol.17 No.2
In this paper, the input current and output voltage ripple of the soft switching interleaved boost converter was analyzed. Ripples of input current and output voltage with an interleaved method is analysed and as a result, the facts that it has lower ripple current than conventional interleaved method is verified. it means that a capacity of a main inductor can be reduced. Besides, a low capacitance of capacitor which means high lifetime and confidence can be used because of reducing ripples of output voltage. In order to verify the validity of the proposed converter used 10uF film capacitor, experiment was performed, and the efficiency of the proposed converter was measured with variable load and duty conditions.