• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.135-139
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• 2012

A digital controller can simply realize a complex operation algorithm and power control process which can not be applied by an analog circuit for a solar array regulator(SAR). The digital resistive control(DRC) makes an equivalent input impedance of the SAR be resistive characteristic. The resistance of the solar array varies largely in a voltage source region and slightly in a current source region. Therefore when the solar array regulator is controlled by the DRC, the Advanced Incremental Conductance MPPT Algorithm with a Variable Step Size(AIC-MPPT-VSS) is suitable. The AIC-MPPT-VSS, however, using small signal resistance and large signal resistance of the solar array can not limit the absolute value of the solar array power. In this paper, the solar array power limiter is suggested and the BUCK-BOOST type SAR which is fully controlled by the digital controller is verified by simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.16-23
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• 2006

This paper presents a novel single-stage high frequency resonant inverter link type DC-DC converter using zero voltage switching with high power-factor. The proposed topology is integrated half-bridge boost rectifier as power factor corrector(PFC) and half-bridge high frequency resonant converter into a single-stage. The input stage of the half-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. Simulation results have demonstrated the feasibility of the proposed high frequency resonant converter. Characteristics values based on characteristics analysis through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter will be able to be practically used as a power supply in various fields as induction heating applications, fluorescent lamp and DC-DC converter etc.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.387-388
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• 2016

본 논문은 V2G를 위한 Bidirectional OBC를 제안한다. 상용화 시 적시 적용 가능한 높은 역/전송 효율의 Bidirectional OBC 전력회로를 제안하고 베터리 전력을 입력원으로 분산형 전력공급 장치에서 요구하는 품질을 만족하는 전력 생산을 위해 계통연계 회로 및 제어 기술을 제안한다. Bidirectional OBC의 PFC Type은 양방향 구현을 위해 기존 MOSFET과 Diode로 구현된 구조와 달리 모두 IGBT를 이용하여 Single Phase Inverter를 구현 하였으며, IGBT 이용 시 예측되는 Reverse Recovery Loss 개선을 위하여 Hybrid Switch 구조를 제안 하였다. Bidirectional OBC의 DC/DC Type은 전송 및 역송에 따라 Buck동작과 Boost 동작이 가능하도록 설계 하였고 Secondary LC Resonant Topology 가변구조법을 사용 하였다.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.255-258
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• 1996

A new low conduction loss, low cost zero-voltage-transition power factor correction circuit(PFC) is presented. Conventional PFC which consists of a bridge diode and a boost converter(one switch) always has three semiconductor conduction drops. Two switch type PFCs reduces conduction loss by reducing one conduction drop but the cost is increased because of increased number of active switches. The proposed PFC reduces conduction loss with one switch, which allows low cost. Conduction loss improvement is a little bit less than that of two switch type, but very close up. Operation and features are comparatively illustrated and verified by simulation and experimental results of 1 kW laboratory prototype.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.665-669
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• 2000

Recently the problem of energy branch become worse increasingly. Therefore many researches about new energy source are processing in several places around are processing in several places around the world. Especially solar energy has many advantages like as purity and infinity. Photovoltaic(PV) system can be classified into two types : One is stand alone type and the other is utility interactive one. Utility interactive type PV system need some technology that Maximum peak power tracking(MPPT) and Anti-islanding and Active Power filter(APF). For APF operation dc-link voltage should be high to supply sufficient output current which needed for harmonic current compensation so usually DC-DC converter is used for boost. In this paper DC-DC converter for PV system and controller for dc-link voltage control are analyzed and designed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.467-472
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• 2005

In this paper, design and control of the novel SEPIC-Flyback converter(SF converter) is developed as a possible converter for fuel cell system. This output characteristic of SF converter is similar to Buck-Boost converter in that it can step-up or step-down the voltage. With the small signal equivalent circuit modeling of SF converter, control-to-output transfer function is obtained. SF converter couples up the inductive type converter to capacitive type converter with one transformer, which has less ripple current than its respective one does. To verify the validity of the proposed converter, 500W, 100kHz converter is designed and tested. ZVS switching and active clamping are also tested in practice.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.166-168
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• 2004

Conventional Switched Mode Power Supplies(SMPS) with diode-capacitor rectifier have distorted input current waveform with high harmonic order contents. Typically, these SMPS have a power factor lower than 0,7. To improve with this problem the power factor correction(PFC) circuit of power supplies has to be introduced. Specially, to the reduce size and manufacture cost of power conversion device, the single-stage PFC converter is increased to demand as necessary of study. In this paper, comparative analysis of Valley-fill, boost and feedforward type single stage power factor correction circuit based on the flyback converter is given. Also, the validity of designed three type of single stage PFC circuit are confirmed by simulation and experimental results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1999.11a
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• pp.290-295
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• 1999

This paper describes Trans-less type utility interactive system that is combined with buck/boost chopper applying partial resonant method, which remove Trans, and high efficient PWM inverter. Therefore, it is possible to make it lightweight, to cut down the cost, and to improve its reliability. What the merits of this system are that we con transmit arbitrary power to load and utility regardless of generating voltage magnitude and we can always obtain high factor controlling by equal phase signal with utility.

• Journal of Ginseng Research
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• v.36 no.4
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• pp.354-368
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• 2012

Thousands of literatures have described the diverse role of ginseng in physiological processes such as cancer, neurodegenera tive disorders, insulin resistance, and hypertension. In particular, ginseng has been extensively reported to maintain homeostasis of the immune system and to enhance resistance to illness or microbial attacks through the regulation of immune system. Immune system comprises of different types of cells fulfilling their own specialized functions, and each type of the immune cells is differentially influenced and may be simultaneously controlled by ginseng treatment. This review summarizes the current knowledge on the effects of ginseng on immune system. We discuss how ginseng regulates each type of immune cells including macrophages, natural killer cells, dendritic cells, T cells, and B cells. We also describe how ginseng exhibits beneficial effects on controlling inflammatory diseases and microbial infections.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1427-1434
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• 2003

Turbo- or Super-charging has been used to boost engine power for Gasoline- and Diesel Engine since beginning of 20th century. So far turbo-charger has enjoyed a high reputation in the charging field for its technical advantages such as no demand of operation power from engine and an excellent charging effect in a static operation at mid- and high engine speed. A mechanically driven super-charger, however, is now popular due to the high engine power at quick change of the driving mode - high engine torque even at low engine speed. Since super-charger needs operation power from engine, it is difficult to improve its relatively higher fuel consumption than that of turbo-charger. This negative point is still an obstacle to the wide use of supercharger. Super-charger using screw-type compressor will fulfill the purpose to reduce fuel consumption by minimizing operation power owing to no charge at idling or part load driving condition. This study aims to develop power control concept to achieve the minimization of operation power. A screw type super-charger was modified in design partially and installed with an internal bypass valve and a bypass tube to control charging pressure at part load. The various control concepts show a possibility to reduce operation power of super-charger.