• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.260-264
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• 1998

Three phase Boost/Buck converter which have economical merits and simple control scheme, are analyzed and evaluated through comparative methods and digital simulation for equivalent load. Those play a part of voltage boost/buck as well as power factor correction with single switch. Controller operating in constant and variable frequency is used for rapid output response and stable system condition respectively. Moreover low THD property of single switched converters is available for inverter arc welding machine known as high power and low power factor. So, in this paper a comparison of the characteristics in boost and buck converter is described and then simulation results conforms the merits from point of view of power factor and voltage regulator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1114-1116
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• 2002

The characteristics of voltage drop and THD for parallel operating 11 PCRs (Phase Controlled Rectifiers) are analysed. The PCRs are used to drive high current (1.6 kA ${\sim}$ 3.7 kADC) electromagnetic coils for electromagnets. All the PCRs operate simultaneously in pulsed mode, and the pulse shot occurs every 150 seconds. During the pulse operation the PCR output current ramps up for 4 seconds, and then keeps flat top state for 2 seconds, and finally ramps down for 4 seconds. For the flat top mode a severe voltage drop and distortion appear in the power system because transformers for the PCRs are designed considering pulsed mode operation. It is expected that the analysis method can be applied to improve the system performance including power factor and design of high power pulsed mode operating power supply systems.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1996년도 추계학술발표회논문집
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• pp.104-108
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• 1996

This paper deals with the design considerations and characteristics analysis of a SCR rectifier in pulsed over load operation. The Pulse repetition rate is one every 150 seconds and each current pulse width is 10 seconds. Therefore the characteristics of the transformer and SCR rectifier which consist the pulsed DC power supply are different from those of the conventional AC/DC power converters having continuous load. The variations of the DC output voltage drop, PF and THD versus the %Z of the transformer is analyzed through simulations and the experimental results thought to be useful in design high power pulsed DC power suppler.

• Journal of Power Electronics
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• 제16권6호
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• pp.1991-2004
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• 2016

An LC filter is required to reduce the output current ripple in the auxiliary resonant snubber inverter (ARSI) for high-performance applications. However, if the traditional control method is used in the ARSI with LC filter, then unnecessary current flows in the auxiliary circuit. In addressing this problem, a novel load-adaptive control that fully uses the filter inductor current ripple to realize the soft-switching of the main switches is proposed. Compared with the traditional control implemented in the ARSI with LC filter, the proposed control can reduce the required auxiliary current, contributing to higher efficiency and DC-link voltage utilization. In this study, the detailed circuit operation in the light load mode (LLM) and the heavy load mode (HLM) considering the inductor current ripple is described. The characteristics of the improved ARSI are expressed mathematically. A prototype with 200 kHz switching frequency, 80 V DC voltage, and 8 A maximum output current was developed to verify the effectiveness of the improved ARSI. The proposed ARSI was found to successfully operate in the LLM and HLM, achieving zero-voltage switching (ZVS) of the main switches and zero-current switching (ZCS) of the auxiliary switches from zero load to full load. The DC-link voltage utilization of the proposed control is 0.758, which is 0.022 higher than that of the traditional control. The peak efficiency is 91.75% at 8 A output current for the proposed control, higher than 89.73% for the traditional control. Meanwhile, the carrier harmonics is reduced from -44 dB to -66 dB through the addition of the LC filter.

• 전력전자학회논문지
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• 제12권3호
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• pp.267-275
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• 2007

본 논문은 현재 청정에너지의 개념으로 대두되고 있는 에너지원 가운데 기계적인 에너지로 저장하여 필요 시 꺼내어 사용할 수 있는 플라이휠 에너지 저장장치에 대한 에너지 입, 출력 모델링 및 PWM 인버터 시스템의 해석 및 제어에 관한 논문으로서, 플라이휠 저장장치 특성 및 시스템 모델링에 관해 논의한다. 재질에 따른 플라이휠의 특성과 플라이휠 에너지 저장장치의 속도 특성에 따른 전압과 전류의 변화량을 수식으로 간략화 하여 분석하고, 시뮬레이션을 통하여 플라이휠의 에너지 저장상태를 분석하였다. 또한, 부하측 전원의 이상유무에 관계없이 에너지를 공급할 수 있는 Online UPS로 사용하기 위해 PDFF 제어기법을 이용하여 전압제어 및 전류제어의 이중루프 제어로 구성된 단상 PW방식의 인버터 시스템 제작하였으며, 실험을 통하여 실제로 0.1[p.u], 1[p.u]에서의 제어되는 전압, 전류제어파형 및 THD 특성에 관하여 평가한다.