• Journal of Power Electronics
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• 제14권3호
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• pp.421-431
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• 2014

A DSP-based self-adaptive proportional-integral (PI) controller to control a DC-DC converter is proposed in this paper. The full-bridge topology is adopted here to obtain higher power output capability and higher conversion efficiency. The converter adopts the zero-voltage-switching (ZVS) technique to reduce the conduction losses. A parallel secondary active clamp circuit is added to deal with the voltage overshoot and ringing effect on the transformer's secondary side. A self-adaptive PI controller is proposed to replace the traditional PI controller. Moreover, the designed converter adopts the constant-current and constant-voltage (CC-CV) output control strategy. The secondary active clamp mechanism is discussed in detail. The effectiveness of the proposed converter was experimentally verified by an IGBT-based 10kW prototype.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.311-314
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• 2003

In this paper, proposed circuit proposes that Active-Clamp-Circuits basis of a current-fed inverter linked type high frequency resonant dc-dc converter of conventional. and the paper the most of characteristics of the reduced high voltage stress main switches with active clamp circuits and output current constant with the resonant part consists of L, C resonant tank circuit. Also, the capacitor (C$_1$, C$_2$) connected in switches are a common using by resonance capacitor and ZVS capacitor. and circuit analysis used state equation of each part modes. Also we conform a rightfulness theoretical analysis by comparing a parameters values and simulation values obtained from simulation using Power MOS-FET as switching devices.

• 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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.400-402
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• 2008

A new interleaved forward converter, adopting series-input parallel-output structure with a common transformer reset circuit, is proposed in this paper. Series-input structure distributes the voltage stress on switches, which makes it suitable for high input voltage application. Paralleling output stage with an interleaving technique enables the circuit handle large output current and reduces filter size. In addition, since two forward converters share one active-clamp circuit for the transformer reset, its primary structure is simplified. All these features make the proposed converter promising for high input voltage applications with high efficiency and simple structure.

• 조명전기설비학회논문지
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• 제24권5호
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• pp.136-144
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• 2010

본 논문에서는 2개의 액티브 클램프 포워드 컨버터로 구성된 투 스위치 인터리브 액티브 클램프 포워드 컨버터를 제안하고자 한다. 제안된 컨버터는 단지 2개의 스위치만을 필요로 하며, 각 스위치는 상호 보조스위치로서 동작하기 때문에 회로의 구성이 간단하고 저비용의 용이한 제어를 특징으로 한다. 아울러 부가적인 공진 인덕터로 인하여 데드타임 동안에 영전압 스위칭 동작이 가능하다. 제안된 컨버터는 인터리브 동작으로 인하여 출력 전압 및 전류 리플이 저감되므로 출력 필터의 크기를 줄일 수 있으며, 그로인하여 컨버터의 부피를 감소시킬 수 있다. 본 논문에서는 제안된 투 스위치 인터리브 액티브 클램프 포워드 컨버터의 모드별 해석과 특성을 논의하였으며, 160[W]급 시작품을 제작하여 그 타당성을 검증하였다.

• 조명전기설비학회논문지
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• 제29권5호
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• pp.57-64
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• 2015

This paper proposes a new switching algorithm for an controllable clamp snubber to improve the efficiency of a fly-back converter system. This system uses an controllable clamp method for the snubber circuit for the efficiency and reliability of the system. However, the active clamp snubber circuit has the disadvantage that system efficiency is decreased by switch operating time because of heat loss in resonance between the snubber capacitor and leakage inductance. To address this, this paper proposes a new switching algorithm. The proposed algorithm is a technique to reduce power consumption by reducing the resonance of the snubber switch operation time. Also, the snubber switch is operated at zero voltage switching by turning on the snubber switch before main switch turn-off. Experimental results are presented to show the validity of the proposed controllable clamp control algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 전문대학교육위원 P
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• pp.13-15
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• 1999

The zero voltage and zero current switching(ZVZCS) full bridge (FB) PWM converter using secondary active clamp is characterized by high efficiency, good ZVZCS characteristic, simple topology and low cost. But at the period for discharge of the secondary clamp capacitor, peak pulses and ringing pulse occur in rectified secondary side of the converter. In this paper, a novel secondary active clamp circuit for the ZVZCS FB PWM converter is proposed and a 50 kHz, 500 W prototype converter was experimented for verification of the converter characteristics. It was verified that high voltage peak pulses and ringing pulse on secondary rectified waveforms of the converter are decreased effectively.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.520-522
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• 2008

A novel two-switch active clamp forward converter suitable for high input voltage applications is proposed. The main advantage of the proposed converter, compared to the conventional active forward converters, is that circuit complexity is reduced and the voltage stress of the main switches is effectively clamped to either the input voltage or the clamping capacitor voltage by two clamping diodes without limiting the maximum duty ratio. Also, the clamping circuit does not include additional active switches, so a low cost can be achieved without degrading the efficiency. Therefore, the proposed converter can feature high efficiency and low cost for high input voltage applications. The operational principles, features, and design considerations of the proposed converter are presented in this paper. The validity of this study is confirmed by the experimental results from a prototype with 200W, 375V input, and 12V output.

• 전력전자학회논문지
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• 제17권3호
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• pp.230-237
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• 2012

This paper proposes an active-clamp ac-dc converter with direct power conversion that has a simple structure and achieves high efficiency. The proposed converter is derived by integrating the step-down ac chopper and the output-voltage doubler. The proposed converter provides direct ac-dc conversion and dc output voltage without using any full-bridge diode rectifier. The step-down ac chopper using an active-clamp mechanism serves to clamp the voltage spike across the main switches and provides zero-voltage turn-on switching. The resonant-current path formed by the leakage inductance of the transformer and the resonant capacitor of the output-voltage doubler achieves the zero-current turn-off switching of the output diodes. The operation principle of the converter is analyzed and verified. A 500W prototype is implemented to show the performance of the proposed converter. The prototype provides maximum efficiency of 95.1% at the full load.

• Journal of Power Electronics
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• 제15권1호
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• pp.86-95
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• 2015

An active clamp high step-up boost converter with a coupled inductor is proposed in this paper. In the proposed strategy, a coupled inductor is adopted to achieve a high voltage gain. The clamp circuit is included to achieve the zero-voltage-switching (ZVS) condition for both the main and clamp switches. A rectifier composed of a capacitor and a diode is added to reduce the voltage stress of the output rectifier diode. As a result, diodes with a low reverse-recovery time and forward voltage-drop can be utilized. Since the voltage stresses of the main and clamp switches are far below the output voltage, low-voltage-rated MOSFETs can be adopted to reduce conduction losses. Moreover, the reverse-recovery losses of the diodes are reduced due to the inherent leakage inductance of the coupled inductor. Therefore, high efficiency can be expected. Firstly, the derivation of the proposed converter is given and the operation analysis is described. Then, a steady-state performance analysis of the proposed converter is analyzed in detail. Finally, a 250 W prototype is built to verify the analysis. The measured maximum efficiency of the prototype is 95%.