• 전력전자학회논문지
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• 제18권4호
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• pp.359-366
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• 2013

This paper proposes a zero-current-transition(ZCT) synchronous buck converter using auxiliary circuit with soft-switching for light weight and high efficiency. In this scheme, an auxiliary circuit is added to the conventional synchronous rectifier buck converter and used to achieve soft-switching condition for both the main switch and synchronous switch. In addition, the switch in the auxiliary circuit operates under soft-switching conditions. Thus, the proposed converter provides a higher efficiency. The basic operations, in this paper, are discussed and design guidelines are presented. The usefulness of the proposed converter is verified on a 200KHz, 20 W prototype converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.243-246
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• 1997

In this paper, soft switching high power factor buck converter is proposed. This converter is composed of diode rectifier, a input capacitor can be small enough to filter input capacitor can be small enough to filter input current, buck converter with loss less snubber circuit. Converter is operated in discontinous conduction mode, turn of of the switching device is a zero current switching(ZCS) and high power factor input is obtained. In addition, zero voltage switching(ZVS) at turn of is achieved and switching loss is reduced using loss less snubber circuit. The capacitor used in the snubber circuit raised output voltage. Therefore, proposed converter has higher output voltage and higher efficiency than conventional buck type converter at same duty factor in discontious conduction mode operation.

• Journal of Power Electronics
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• 제11권5호
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• pp.655-661
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• 2011

This paper presents two topologies for single-stage single-phase double-buck type PFC converters, designed to operate at high power factor, near sinusoidal input currents and adjustable output voltage. Unlike the known buck type PFC topologies, in which the output voltage is always lower than the maximum input voltage, the proposed converters can operate at output voltages higher than the ac input peak voltage. A reduced number of switches on the main path of the current are another characteristic of the two proposed topologies. To shape the input line currents, a fast and robust controller based on a sliding mode approach is proposed. This active non-linear control strategy, applied to these converters allows high quality input currents. A Proportional Integral (PI) controller is adopted to regulate the output voltage of the converters. This external voltage controller modulates the amplitude of the sinusoidal input current references. The performances of the presented rectifiers are verified with experimental results.

• 한국조명전기설비학회지:조명전기설비
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• 제11권4호
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• pp.100-108
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• 1997

기동 돌입전류가 없는 역률개선을 위한 강압형과 승합형이 결합된 형태의 새로운 푸시풀 퀀텀 직렬공진형 정류기를 제안한다. 제안된 정류기의 동적모델링을 개발하여 기동 돌입전류를 제거하는 제어기법을 제안하였으며 컴퓨터 시뮬레이션과 실험을 통하여 제안된 정류기와 제어기법의 유용성을 보였다. 제안된 방식으로 고역률과 넓은 출력진압 범위를 얻었다.

• 전력전자학회논문지
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• 제15권5호
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• pp.394-400
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• 2010

본 논문에서는 Buck Converter 동작 원리를 Full -Bridge Inverter에 적용한 전자식 안정기를 제안하였다. 전자식안정기는 EMI 필터, 수동 PFC, Full-Bridge Inverter로 2-stage로 구성되어 있다. PFC는 신뢰성 확보를 위해 수동 PFC를 사용하였다. Full-Bridge Inverter는 High Side와 Low Side 스위치의 구동 주파수를 각각 고주파와 저주파로 구동하여 Buck Converter의 동작을 구현 하였다. 램프를 저주파수 구형파로 구동하여 음향공명현상을 피하게 되었으며, 고주파수 스위칭으로 인덕터의 부피를 줄였다. 제안한 방법은 시뮬레이션과 실험을 통해 증명하였다.

• 전력전자학회논문지
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• 제4권1호
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• pp.82-90
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• 1999

본 논문은 단일 스위치 3상 ZCS 강압형 정류기의 펄스주파수 제어기법을 다루고 있다. 제안하는 펄스주파수 제어방법은 거의 정현적인 입력전류를 흐르게 하여 3상 강압형 정류기의 성능을 보여준다. 제안하는 제어구조의 유용성을 검증해 주는 시뮬레이션과 실험 결과는 단일 스위치 3상 ZCS 강압형 정류기의 고역율, 입력전류의 낮은 THD, 부하 변동에 대한 전압의 응답특성들이 뛰어남을 보여준다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.658-662
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• 1998

A pulse frequency modulation control method for single-switch three-phase buck rectifiers is comprehensively studied in this paper. The proposed pulse frequency control method leads the three-phase buck rectifier to high performance system that can draw the nearly sinusoidal imput-line currents. The simulated and experimental results demonstrate that the system provides low total harmonic distortion of the input-line currents, high-power factor, and good output voltage regulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.423-427
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• 1998

A new single-switch, three-phase, high power factor, multi-resonant, ZCS buck rectifier that operates in the continuous conduction mode has been reported. Basically, pulse frequency modulation method should be adopted to suitably control the system. This paper puts main focus on the methods how the pulse frequency modulation can be implemented and a comprehensive investigation on the corresponding control loops is coducted.

• Journal of Power Electronics
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• 제2권1호
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• pp.46-54
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• 2002

In this paper a neural network controller for achieving maximum power tracking as well as output voltage regulation, for a wind energy conversion system (WECS) employing a permanent magnet synchronous generator is proposed. The permanent magnet generator (PMG) supplies a dc load via a bridge rectifier and two buck-boost converters. Adjusting the switching frequency of the first buck-boost converter achieves maximum power tracking. Adjusting the switching frequency of the second buck-boost converter allows output voltage regulation. The on-time of the switching devices of the two converters are supplied by the developed neural network (NN). The effect of sudden changes in wind speed and/ or in reference voltage on the performance of the NN controller are explored. Simulation results showed the possibility of achieving maximum power tracking and output voltage regulation simulation with the developed neural network controllers. The results proved also the fast response and robustness of the proposed control system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.656-659
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• 2001

In this paper a neural network controller for achieving maximum power tracking as well as output voltage regulation, for a wind energy conversion system(WECS) employing a permanent magnet synchronous generator, is proposed. The permanent magnet generator (PMG) supplies a dc load via a bridge rectifier and two buck-boost converters. Adjusting the switching frequency of the first buck-boost converter achieves maximum power tracking. Adjusting the switching frequency of the second buck-boost converter allows output voltage regulation. The on-times of the switching devices of the two converters are supplied by the developed neural network(NN). The effect of sudden changes in wind speed ,and/or in reference voltage on the performance of the NN controller are explored. Simulation results showed the possibility of achieving maximum power tracking and output voltage regulation simultaneously with the developed neural network controller. The results proved also the fast response and robustness of the proposed control system.