• Journal of Power Electronics
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• 제12권1호
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• pp.164-171
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• 2012

Variable step size maximum power point trackers (MPPTs) are widely used in photovoltaic (PV) systems to extract the peak array power which depends on solar irradiation and array temperature. One essential factor which judges system dynamics and steady state performances is the scaling factor (N), which is used to update the controlling equation in the tracking algorithm to determine a new duty cycle. This paper proposes a novel stability study of variable step size incremental resistance maximum power point tracking (INR MPPT). The main contribution of this analysis appears when developing the overall small signal model of the PV system. Therefore, by using linear control theory, the boundary value of the scaling factor can be determined. The theoretical analysis and the design principle of the proposed stability analysis have been validated using MATLAB simulations, and experimentally using a fixed point digital signal processor (TMS320F2808).

• 전기전자학회논문지
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• 제23권2호
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• pp.495-501
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• 2019

본 논문에서는 정류 브리지 다이오드를 갖는 단상 무정전전원장치의 전원측 고조파 및 역률 개선을 위한 가변형 고조파 필터를 제안한다. 2레벨 이상의 전력변환방식을 적용한 무정전전원장치는 전원측 고조파 및 역률 특성이 우수한 반면, 전 브리지 방식의 무정전전원장치는 전원측에 제 3고조파, 제 5고조파, 제 7고조파 및 역률 저하를 심각하게 야기한다. 이에 따라 단상 전 브리지 동작에 의해 야기된 (2n+1)차 고조파 제거 및 역률 개선을 위한 가변형 고조파 필터를 제안하고자 한다. 제안한 가변형 고조파 필터의 성능을 평가하기 위해 다양한 시뮬레이션과 실험을 진행하여 타당성을 검증하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권6호
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• pp.336-341
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• 1999

In this paper a control method to compensate the fluctuation in source voltage by using reactive current is presented. When the source voltage is changed within $\pm$10[%] range, the unit power factor is carried out. Otherwise, the converter is controlled by variable power factor. By using above control, the converter input voltage is maintained constantly. And then it was certified by simulation with the ACSL and several experiments.

• 한국조명전기설비학회지:조명전기설비
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• 제8권3호
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• pp.36-43
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• 1994

본 연구는 교류전원측에서 콘버터에 의해 출력전압조정과 동시에 입력전류가 전압과 동상에 가까운 정현파가 되도록 하기 위해 고주파 스위칭에 의한 단상 부스터 콘버터의 제어방식을 분석하고 가변밴드폭 제어방식에 의해 1[kW]부하에 대하여 각 파라메타를 산정하며 실험장치를 구성하여 주파수 스팩트럼 분석기에 의한 분석을 토대로 고역률 동작을 확인하고자 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.1038-1040
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• 1993

Single phase AC to DC Boost-converter which is control led with a variable hysteretic current mode for improvent of input power factor makes high power factor possible. Power Factor correction circuit can be identified with a determination of each parameters. A simaluation and experiment result to load and parameter variation is examined.

• Journal of Power Electronics
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• 제14권5호
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• pp.890-898
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• 2014

Critical conduction mode boost power factor correction converters operating at the boundary of continuous conduction mode and discontinuous conduction mode have been widely used for power applications lower than 300W. This paper proposes an enhanced variable on-time control method for the critical conduction mode boost PFC converter to improve the total harmonic distortion characteristic. The inductor current, which varies according to the input voltage, is analyzed in detail and the optimal on-time is obtained to minimize the total harmonic distortion with a digital controller using a TMS320F28335. The switch on-time varies according to the input voltage based on the computed optimal on-time. The performance of the proposed control method is verified by a 100W PFC converter. It is shown that the optimized on-time reduces the total harmonic distortion about 52% (from 10.48% to 5.5%) at 220V when compared to the variable on-time control method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.163-167
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• 2000

This paper presents the digital control of single-phase power factor correction(PFC) converter which has the variable gain according to the condition of inner control loop error. Generally the gain of inner current control loop in single-stage PFC converter has a constant magnitude. This has a bad influence on the power factor because current loop doesn't operate smoothly in the condition that input voltage is low In particular a digital controller has more time delay than an analog controller and degrades This drops the phase margin of the total digital PFC system,. It causes the problem that the gain of current control loop isn't increased enough. In addition the oscillation happens in the peak value of the input voltage open loop PFC system gain changes according to ac input voltage. These aspects make the design of the digital PFC controller difficult The digital PFC controller presented in this paper has a variable gain of current control loop according to input voltage. The 1kW converter was used to verify the efficiency of the digital PFC controller.

• 한국화재소방학회논문지
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• 제22권2호
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• pp.9-19
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• 2008

최근 다른 행정조직에 비하여 연구가 부족했던 소방행정분야에 체계적인 변화가 나타나고 있다. 특히, 소방수요가 증가하고 형태가 다양화되고 있는데, 가장 시급한 일은 소방수요에 맞게 소방력을 확보하는 일이다. 이러한 소방력의 배치는 주민들의 사회적 후생의 만족으로 이어질 것이다. 본 연구의 목적은 소방력의 결정요인을 찾아보고 소방수요가사회 경제적 요인의 영향을 받는지 알아보는데 있다. 이를 위하여 본 연구에서는 소방력, 소방수요, 사회 경제적 요인, 재정적 요인에 대한 조사를 실시하였다. 그 다음, 이론적 배경과 과거연구를 근거로 4가지 가설을 설정하였다. 가설을 검증하기 위한 통계적 방법은 회귀방정식과 구조방정식분석이다. 본 연구 결과, 소방력은 소방수요와 재정적 요인에 의해서는 양(+)의 유의적인 영향을 받았으나, 사회 경제적인 요인에 의해서는 음(-)의 유의적인 영향을 받았다. 또한 소방수요는 경제적인 요인에 의해서는 양(+)의 영향을 받았으나, 사회적인 요인은 음(-)의 영향을 미친 것으로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.240-243
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• 2001

This paper presents the digital controller using variable gain for single-phase power factor correction (PFC) converter. Generally, the gain of inner current control loop in single-stage PFC converter has a constant magnitude. This is why input current is distorted under low input voltage. In particular, a digital controller has more time delay than an analog controller which degrades characteristics of control loop. So, it causes the problem that the gain of current control loop isn't increased enough. In addition, the oscillation happens in the peak value of the input voltage open loop PFC system gain changes according to ac input voltage. These aspects make the design of the digital PFC controller difficult. In this paper, the improved digital control method for single-phase power factor converter is presented. The variable gain according to input voltage and input current help to improve current shape. The 800W converter is manufactured to verify the proposed control method.

• KIEE International Transactions on Power Engineering
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• 제4A권2호
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• pp.51-57
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• 2004

This paper describes the dynamic performance of a variable speed wind turbine system responding to a wide variety of wind variations. Modeling of the wind generation using power electronics interface is proposed for dynamic simulation analysis. Component models and equations are addressed and their incorporations into a transient analysis program, PSCAD/EMTDC are provided. A wind model of four components is described, which enables observing dynamic behaviors of the wind turbine resulting from wind variations. Controllable power inverter strategies are intended for capturing the maximum power under variable speed operation and maintaining reactive power generation at a pre-determined level for constant power factor control or voltage regulation control. The components and control schemes are modeled by user-defined functions. Simulation case studies provide variable speed wind generator dynamic performance for changes in wind speed