• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2217-2220
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• 1997

To achieve the high performance speed control of synchronous permanent magnet motor, the influence of iron loss can not be negleced as the increase of driving frequency with high speed operation. This paper proposes a maximum efficiency control algorithm for permanent magnet synchonous motors by controlling the d-axis component of the armature current at any speed and torque. The objective of the optimum efficiency controller is to seek a combination of d-q axis current components which provide minimum input power (minimum losses) at a certain operating point by adding a small amout of perturbation to the d-axis current reference.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1948-1950
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• 1997

In this paper, we compose of the single current source inverter for utility interactive photovoltaic system. According to insert parallel resonant circuit, the do reactor decreases the distortion of dc current and output current. Therefore, we decrease the do reactance and control modulation factor to operation at the maximum power point around of solar cell.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.6
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• pp.1010-1016
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• 2004

In this paper, a scheme for estimating the parameters of solar cells and a NN-based emulator for predicting the maximum power point are presented. The diode model with series and shunt resistors is used to estimate parameters highly affecting its V-I characteristic curve and both a real-coded genetic algorithm and the model adjustment technique are employed. For implementing the emulator, a multi-layered neural network incorporating with the BP algorithm is used. A set of simulation works using both field data and generated data are carried out to demonstrate the effectiveness of the proposed method.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.276-282
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• 2012

This study looked for Mode status of each for fatigue crack growth behavior about the repeat load of mode I and the static load of mode II. The experiment was performed in the state of the repetition frequency of the sine wave 10Hz, the stress ratio 0.1, maximum load 300kg.f, a static load 0, 100, 200, 300kg.f, As the experimental results, in mode of static load, while the load value increases, the crack growth rate is slower as the energy of a crack mixing grows. Mode I and the power mode II get an influence each other in the direction of crack propagation path, but as they eventually get closer to the breaking point of the crack growth, it is dominated by the mode I.

• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.87-92
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• 1996

When cutting 2.0cm-thick red oak and hard maple with an air-jet-assisted carbon-dioxide laser of 2kW output power, maximum feed speed at the point of full penetration of the beam decreased with increasing the angle between grain and cutting direction. Feed speed averaged 3.75 and 3.38 meters per minute for red oak and hard maple, respectively. Gray-level of laser-cut surfaces were analyzed by image analysis system. The highest gray level of laser-cut surface was obtained when red oak was cut parallel to grain by laser. Surface profiler was used to scan the sawn and laser-cut surfaces. Center line average roughnesses of laser-cut surfaces were higher than those of sawn surfaces. Scanning electron micrographs showed the cell walls which were melted by laser.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.32-34
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• 2011

본 논문은 최대전력추종 태양광 충전법을 적용한 LED 동기점멸등 제어시스템 설계 및 구현을 목표로 한다. 즉, 선박의 야간 안전항해를 돕기 위한 항로표지인 등부표에 장착되는 LED 동기점멸등의 구동제어 시스템, 최대전력추종 방식의 전류제어 벅 컨버터를 적용한 배터리 충전시스템의 설계 및 구현, 그리고 그 특성파악에 대해 중점적으로 다룬다. 시스템에 적용한 태양광 모듈의 모델링 및 MATLAB 시뮬레이션을 통해 추출한 태양전지 파라미터를 충전회로 시스템에 적용하여 최대전력추종 태양광 충전시스템을 설계하였다. 따라서, 본 논문에서는 원칩 마이크로컨트롤러를 사용하여 최대전력추종(MPPT) 태양광 충전제어시스템과 GPS활용 LED 동기점멸등 구동제어시스템을 구현하여, 그 특성파악을 통한 실시스템 적용가능성을 확인하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.47-48
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• 2011

PV(Photovoltaic) cell의 출력 전력은 일사량이나 온도와 같은 외부환경의 영향을 받아 변화하게 되므로 PV cell은 전압과 전력의 출력에 있어 비선형적이다. 이와 같은 비선형적 관계로 인해 MPPT(Maximum Power Point Tracking)를 수행하는 것이 PV 시스템에서는 매우 중요하다. 본 논문에서는 PV의 전력-전압 출력 특성에서 MPP를 기준으로 양쪽 경사면의 기울기와 Section의 차이를 이용한 새로운 추종법을 제안하였다. P-V 특성 곡선에서 왼쪽 측면에 비해 오른쪽 측면이 큰 기울기를 갖는 동시에 좁은 Section을 가지므로 제안하는 알고리즘은 이러한 특성을 활용한다. 또한 EMTP를 이용하여 제안된 기법의 성능과 동작을 검증하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1392-1393
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• 2011

This paper proposes fuzzy logic control maximum power point tracking(FLC MPPT) of photovoltaic(PV) pump system using IPMSM. Conventional MPPT controller was unstable by reason of the ripple-current of DC link in three phase inverter. Thus in this paper the control algorithm of IPMSM using $i_q$ current is composed to improve the insecurity of conventional MPPT controller. Proposed algorithm is operated by simulation with variation radiation condition. And analyze the response characteristic of IPMSM. The validity of this paper is proved by analyzed data.

• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.731-741
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• 2011

Conventional methodologies (empirical, analytical, numerical, hybrid, etc.) for sizing photovoltaic (PV) systems cannot be used when the relevant meteorological data are not available. To overcome this situation, modern methods based on artificial intelligence techniques have been developed for sizing the PV systems. In the present study, the optimum PV/inverter sizing ratio for grid-connected PV systems with orientation due south and inclination angles of $45^{\circ}$ and $60^{\circ}$ in selected Algerian locations was determined in terms of total system output using type-2 fuzzy logic. Because measured data for the locations chosen were not available, a year of synthetic hourly meteorological data for each location generated by the PVSYST software was used in the simulation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.367-370
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• 2009

This paper proposes a novel maximum power point tracking(MPPT) control algorithm considering insolation to improve efficiency of PV system. The proposed algorithm is composed perturb and observe(P&O) method and constant voltage(CV) method. P&O method is simple to realize and CV method is possible to tracking MPP with low insolation. Response characteristics of proposed algorithm is compared to conventional P&O method with insolation variation. This paper proves the validity of proposed algorithm through the analysis result.