• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.303-304
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• 2015

본 논문에서는 CCM에서 동작하는 PFC 인덕터의 AC 권선 손실에 대하여 분석하고, PFC 승압 컨버터의 효율을 개선하기 위해 인덕터의 AC 권선손실을 저감하는 방법을 제안한다. 제안한 방법은 기존의 단일선 대신 Litz선을 사용하고, 권선의 DC 저항 및 인덕터의 창면적을 고려하여 권선을 설계한다. 제안한 방법을 적용한 인덕터와 기존의 인덕터를 PFC 승압 컨버터에 적용하여 실험적으로 손실을 비교함으로써 PFC 승압 컨버터의 효율이 개선되었음을 보인다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.112-114
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• 2020

기존 위상천이 풀브리지 컨버터는 입력전압 범위가 넓을 경우, 제어변수인 듀티의 변동이 크게 되어 큰 순환전류가 존재하고, 2차측 정류단 전압스트레스가 커지는 문제가 있다. 이러한 문제점을 해결하기 위해 본 논문에서는 위상천이 방식을 적용한 3-레그 인버터 타입의 절연형 컨버터를 제안한다. 제안회로는 턴 비의 변화로 입력전압에 상관없이 항상 최대 듀티로 동작하며, 1차측 전류 및 2차측 정류단 전압스트레스를 감소시킬 수 있다. 제안 회로의 타당성을 검증하기 위해, 입력 311V_DC/622V_DC, 출력 50V 6kW급 사양의 프로토타입 컨버터를 설계·제작하였고, 그 실험 결과를 발표한다.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.619-621
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• 2002

In this paper, AC reactor for PWM converter using the metal powder is introduced. Metal powder AC reactor was developed to substitute conventional iron core typed AC reactor in the PWM converter application. The characteristics of the metal powder AC reactor are analyzed and tested. A new reactor has reduced switching noise and loss.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.187-192
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• 2007

The terminal voltage of a synchronous generator is maintained by the field current control of excitation system Generally AC/DC converter which is component of AVR(Automatic Voltage Regulator) system for excitation current control is connected to diode rectifier and DC/DC converter system In the case of diode rectifier system of phase controlled converter, AC/DC converter has low power factor and some low order harmonics in the line current. In this paper, two-stage three-phase PWM AC/DC converter is studied to solve these problems, The proposed method is verified by the computer simulations and experimental results in prototype generation system.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1219-1226
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• 1993

A buck-boost zero current switched(ZCS) series resonant AC to DC converter for the DC output voltage regulation together with high power factor is proposed. The proposed single phase AC to DC converter enables a zero current switching operation of all the power devices allowing the circuit to operate at high swtiching frequencies and high power levels. A dynamic model for this Ac to DC converter is developed and an analysis for the internal operational characteristics is explored. Based on this analysis, a switched discrete sliding mode control(SDSMC) technique is investigated and its advantages over the other types of current control techniques are discussed. With the proposed control technique, the unity power factor without a current overshoot and a wide range of output voltage can be obtained.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1737-1742
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• 2012

The scott transformer is used to supply single-phase power to the AC railway system. Since the scott transformer is a passive facility, it cannot regulate load-side voltage according to load change. Meanwhile, the Voltage Source Converter (VSC) is able to convert the voltage and control active and reactive power. In this paper, the feasibility of a AC railway system based on Back-to-Back (BTB) VSC which is composed of a rectifier, a DC-DC converter, a inverter, has been proposed. A three-phase to single-phase BTB VSC is modeled. The proposed AC railway system based on BTB VSC is tested on Matlab/Simulink.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.36-43
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• 2010

This paper proposes a new type of voltage sag-swell compensator based on a Z-source AC-AC converter. The proposed topology employs a pulse width modulation (PWM) Z-source AC-AC converter along with a injection transformer. A safe commutation strategy is used to eliminate voltage spikes on switches without snubber circuit. During a voltage sag or swell, the proposed system controls the adding or missing voltage and maintains the rated voltage of sinusoidal waveform at the terminals of the critical loads. The proposed system is able to compensate 20[%] voltage swell and is also able to compensate 60[%] voltage sag. In order to control and detect the voltage sag and swell, the peak voltage detection method is applied. Also, the operating principles of the proposed system are described, and a circuit analysis is provided. Finally, PSIM simulation and experimental results are presented to verify the proposed concept and theoretical analysis.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.1
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• pp.70-76
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• 1998

A switch-mode AC/DC converter with high input power factor and sinusoidal input current waveforms is analyzed and modelled for computer simulation. The developed mathematical model for this converter can be used to examine the transient and steady-state performance for selecting the proper ratings of filter, boost inductor and semiconductor devices or the effects of this converter under normal and fault operating conditions on the associated power systems. The proposed model and computer programs are confirmed by comparing with the experimental results.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.148-149
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• 2019

Voltage unbalance can be occured in AC-DC microgrid systems when AC loads or AC systems are connected. To solve this problem, 3-phase 4-wire interlinking converter is used. This paper proposes in PLL method that can detect accurate phase and voltage magnitude.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.695-697
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• 1993

In this paper, a novel concept for a static three-phase to three-phase power converter for an AC drive with an unity power factor and reduced harmonics on the utility line is presented. The power circuit consists of two back-to-back connected six-pulse bridges having only a $5{\mu}F$ ceramic capacitor in the DC link. By controlling the active power balance between two bridges, the DC link voltage can be maintained within 20V deviation from the nominal value with the small ceramic capacitor regardless of the load variation even in the unbalanced source condition.