• 한국전자통신학회논문지
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• 제17권3호
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• pp.459-466
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• 2022

개폐서지는 전력시스템에서 발생하는 과전압 현상 중의 하나이며 변전소의 차단기 등 개폐장치의 동작이나 송전선로의 고장으로 인해 발생한다. 특히 송전선로의 절연설계를 위하여 개폐서지의 피크를 산정하는 것은 매우 중요하고 AC/DC 병가선로의 안정적인 운영을 위한 절연협조의 기본적인 검토항목이다. 본 논문에서는 새로운 AC/DC 병가구조의 전력시스템에 대한 상정해석을 위하여 AC 765kV와 DC ±500kV Bi-Pole 시스템이 조합된 송전선로를 대상으로 하였다. 일반적으로 교류 송전시스템의 절연설계를 위한 비정상적인 과전압은 외부과전압으로 낙뢰에 의한 과전압과 내부과전압으로 개폐에 의한 과전압을 고려한다. 직류 송전시스템의 경우에는 개폐에 의한 과전압 보다 송전선로의 중간에서 지락고장이 발생하면 인접한 정상선로에 유기되는 내부과전압을 개폐서지라하며 직류송전선로에 유기되는 가장 큰 일시적인 과전압을 의미한다. 본 논문의 연구목적으로 구성된 선로에 대하여 EMTDC 소프트웨어를 사용하여 모의하였으며, 다양한 AC/DC 혼합 형태에 대한 개폐과전압의 영향을 검토하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.418-422
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• 1998

A new single stage AC/DC converter based on the forward converter is proposed. The proposed converter offers both the high power factor and the direct conversion from ac line to dc output voltage. Also, the proposed converter reduces the diode conduction loss, so improves the overall efficiency of the converter, compared with other alternatives. The principles of operation and the simulation results of the proposed converter are presented. A 100 W prototype was built and tested to show the potential of applications of the proposed converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.318-320
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• 2007

Single-phase cycloconverters are widely used for ac-ac power conversion especially for speed control of ac drives. In this paper, a new single-phase to single-phase Z-source cycloconverter topology is proposed. The proposed single-phase Z-source cycloconverter can boost to a desired voltage with various frequency. Thus, it is called a frequency step-down and amplitude voltage step-up converter. The operating principle of the proposed topology is presented. Analysis and simulation for this single-phase Z-source cycloconverter are also presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.986-989
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• 2004

The concept and results of a simple constant switching frequency delta modulation scheme suitable for DC-AC power conversion in uninterruptable power supply (UPS) applications are presented. Unlike the traditional delta modulation scheme, the scheme has a well defined harmonic spectrum, resulting in a simple filter design and reduced radio interference.

• Journal of Power Electronics
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• 제3권2호
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• pp.69-80
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• 2003

Computer aided engineering (CAE) is a systematic approach to develop a better product/application with maximum possible options and minimum transition time. This paper presents a comprehensive feasibility analysis of various CAE techniques for evaluation and optimization of power electronic converters and systems. Different CAE methods for analysis, design, and performance improvement are classified. In addition, their advantages compared to the conventional workbench experimental methods are explained in detail and through examples.

• Journal of Power Electronics
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• 제12권2호
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• pp.276-284
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• 2012

AC/AC power conversion is widely used to feed AC loads with a variable voltage and/or a variable frequency from a constant voltage constant frequency power grid or to connect critical loads to an unreliable power supply while delivering a very balanced and accurate sinusoidal voltage system of constant amplitude and frequency. The load specifications will clearly impose the requirements for the inverter stage of the power converter, while wider ranges of choices are available for the rectifier. This paper investigates the utilization of a buck-type current source rectifier as the active front-end stage of an AC/AC converter for applications that require an adjustable DC-link voltage as well as elimination of the low-frequency common mode voltage. The proposed solution is to utilize a combination of two or more zero current vectors in the Space Vector Modulation (SVM) technique for Current Sources Rectifiers (CSR).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1364-1367
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• 2005

In this paper, a novel prototype topology of soft switching PWM controlled high frequency AC power conversion circuit without DC voltage smoothing chemical capacitor filter link from the voltage grid of utility frequency AC power supply source with 60Hz-100V or 60Hz-200V is proposed and introduced for innovative consumer induction heating(IH) boiler applications as hot water producer, steamer and super heated vapor steamer.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.328-329
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• 2020

The AC/DC converter, which connects the AC grid to the DC grid in the microgrid, is a critical component in power sharing and stable operation. Sometimes the AC/DC converters are connected in parallel to increase the transmission and reception capacity. When connected in parallel, circulating current is generated due to line impedance difference or sensor error. As a result of circulating current, there is deterioration and loss in particular PCS(Power Conversion System). In this paper, we propose droop control with novel adaptive virtual impedance for reducing circulating current. Feasibility of proposed algorithm is verified by PowerSIM simulation.

• 전력전자학회논문지
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• 제21권3호
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• pp.224-230
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• 2016

In this study, a single-power-conversion series-resonant ac-dc converter with high efficiency and high power factor is proposed. The proposed ac-dc converter consists of single-ended primary-inductor converter with an active-clamp circuit and a voltage doubler with series-resonant circuit. The active-clamp circuit clamps the surge voltage and provides zero-voltage switching of the main switch. The series-resonant circuit consists of leakage inductance $L_{lk}$ of the transformer and resonant capacitors $ C_{r1}$ and $ C_{r2}$. This circuit also provides zero-current switching of output diodes $D_1$ and $D_2$. Thus, the switching loss of switches and reverse-recovery loss of output diodes are considerably reduced. The proposed ac-dc converter also achieves high power factor using the proposed control algorithm without the addition of a power factor correction circuit and a dc-link electrolytic capacitor. A detailed theoretical analysis and the experimental results for a 1kW prototype are discussed.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.254-256
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• 2007

The Solar energy is either used as a solar thermal energy or converted to electrical power through power conversion system. The latter method is defined as a solar cell changing the solar energy into the direct electric energy or power conversion that convert the dc power into ac power.For the solar cell to be a practical alternative energy, the study should be focused not only on the solar cell ,but also the power conversion system for common power source. In this study, we get the suitable power to common load ,using Ag Grid DSC(Dye-sensitized solar cell). Our purpose is to achieve the common solar cell power generation system ,using converter and PWM(Pulse width modulation) inverter system controled by DSP.