• 전력전자학회논문지
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• 제9권2호
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• pp.134-141
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• 2004

본 논문은 DC/DC 컨버터의 효율을 개선하기 위해 동기정류방식을 제시하였다. 제안된 동기정류 방식은 single winding self-driven synchronous rectification(SWSDSR)로서 1차측은 Push-Pull topology를 사용하였다. 특히 이 방식은 데드타임구간에도 동기정류 스위치를 온 시켜서 효율을 개선 할 수 있다. 최종적인 시뮬레이션과 실험 결과는 자기구동 동기정류(SDSR) 방식과 보조권선을 이용한 자기구동 동기정류(SWSDSR) 방식의 효율에 관한 비교와 해석을 보여준다.

• 전자공학회논문지S
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• 제34S권2호
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• pp.112-120
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• 1997

The clamp mode (CM) forward zero voltage switching multi resonant converter (ZVS-MPC) with self-driven synchronous rectifier is studied. The loss at the synchronous rectification stage of the converter is analyzed using MOSFET piecewise linear model and is compared with the loss at the conventional schottky diode rectification stage of th econverter. From the results of the analysis, it is known that the use fo MOSFETs as a synchronous rectifier reduces the loss at the rectification stage overthe whole load range comparing the use of schottky diodes as a conventional rectifier in the converter. In order to verify the validit of the analysis, we have built a 33W(3.3V/10A) CM forward ZVS-MRC with self-driven synchronous rectifier, in which switching frequency is 1MHz, and tested. FRom the experimental results, it is known that the synchronous rectification achieved about 1W improvement in the loss at the rectification stage and about 3% in the efficiency at the converter as compared with the conventional schottky diode rectification.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.395-399
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• 1996

The Clamp Mode(CM) Forward Zero Voltage Switching Multi Resonant Converter(ZVS-MRC) with self-driven synchronous rectifier in studied. The loss at the synchronous rectification stage of the converter is analyzed using MOSFET linear model and is compared with the loss at the conventional schottky diode rectification stage of the converter. From the results of the analysis, it is known that the use of MOSFETs as a synchronous rectifier reduces the loss at the rectification stage over the whole load range comparing the use of schottky diodes as a conventional rectifier in the converter. In order to verify the validity of the analysis, we have built a 33W(3.3V/10A) CM Forward ZVS-MRC with self-driven synchronous rectifier, in which switching frequency is 1MHz, and tested. From the experimental results, it is known that the synchronous rectification achieved about 1W improvement in the loss at the rectification stage and about 3% in the efficiency at the converter as compared with the conventional schottky diode rectification.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.110-113
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• 1993

The MOSFET synchronous rectification in the Active-Clamp Forward converter is presented. The Active-Clamp Forward converter has little dead time during the off time of the main switch and it is suitable for the MOSFET synchronous rectification comparing to the other Forward converter topologics. Using the MOSFET synchronous rectification on the Active-Clamp Forward converter with 3.3[V] output and 500[kHz] switching frequency, the improvement of efficiency is achieved comparing with the conventional Schottky barrier diode rectification.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.345-351
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• 2003

Single winding self driven synchronous rectification(SWSDSR) scheme is based on an additional winding in the power transformer (auxiliary winding). It allows for maintaining the synchronous rectifiers on even when the voltage in the transformer is zero, which is impossible to do in traditional self-driven approaches. Its technique is verified to improve the efficiency by experiment. In this paper, there are compared self driven synchronous rectification(SDSR) with SWSDSR about the efficiency

• 전력전자학회논문지
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• 제21권2호
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• pp.117-125
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• 2016

In this paper, the inverter switch losses of BLDC motor for three types of PWM methods and power devices were analyzed. When the BLDC motor is driven at low currents, the inverter switch losses for MOSFET are low because MOSFET operates like resistance. However, the inverter switch losses for IGBT are higher than MOSFET due to its large turn-off losses. Moreover, synchronous rectification switching method is adaptable because MOSFET has 2-channel. So, MOSFET can be driven with more low impedance and losses. For low power inverter with MOSFET, the power losses of unified PWM are lower than that of unipolar and bipolar PWM. Proposed method and losses analysis results are verified by examination and simulation using Matlab/Simulink.

• Journal of Power Electronics
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• 제16권6호
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• pp.2035-2044
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• 2016

In order to match the voltages between high voltage battery stacks and low voltage super-capacitors with a high conversion efficiency in hybrid energy sources electric vehicles (HESEVs), a high ratio bidirectional DC-DC converter with a synchronous rectification H-Bridge is proposed in this paper. The principles of high ratio step-down and step-up operations are analyzed. In terms of the bidirectional characteristic of the H-Bridge, the bidirectional synchronous rectification (SR) operation is presented without any extra hardware. Then the SR power switches can achieve zero voltage switching (ZVS) turn-on and turn-off during dead time, and the power conversion efficiency is improved compared to that of the diode rectification (DR) operation, as well as the utilization of power switches. Experimental results show that the proposed converter can operate bidirectionally in the wide ratio range of 3~10, when the low voltage continuously varies between 15V and 50V. The maximum efficiencies are 94.1% in the Buck mode, and 93.6% in the Boost mode. In addition, the corresponding largest efficiency variations between SR and DR operations are 4.8% and 3.4%. This converter is suitable for use as a power interface between the battery stacks and super-capacitors in HESEVs.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권5호
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• pp.351-357
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• 2004

In this paper, we present an analytical method that provides fast and efficient evaluation of the conversion efficiency for switching power supplies. In the proposed method, the conduction losses are evaluated by calculating the effective values of the ideal current waveform first and incorporating them into an exact equivalent circuit model of the switching power supply that includes all the parasitic resistances of the circuit components. While the winding losses and core losses are accurately accounted for the magnetic components, the skin and proximity effects are assumed to be negligible in order to simplify the analysis. The validity and accuracy of the proposed method are verified with experiments on a prototype active-clamped forward converter with synchronous rectification. An excellent correlation between the experiments and theories are obtained for the input voltages of 36-75 V with 4-6 MOSFETs employed for the synchronous rectification.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.1973-1976
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• 1998

Recently, new trend in telecommunication device is to apply low voltage, about 3.3V-1.5V. However, it is undesirable in view of high efficiency and power desity which is the most important requirement in the distributed power system. Rectification loss in the output stage, in on-board converter for distributed power system are constrained to obtain high efficience at low output voltage power suppies. This paper explains the basic operational principles of three kinds of ZVS DC/DC converters with self-driven synchronous rectifier. The three topologies are analyzed by simulation and exprimentation, and the characteristics comparisons of high efficience converter are carried out in view of the minimized rectification losses in the out stage.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.40-41
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• 2017

New adaptive SR (synchronous rectification) control method is proposed offering high efficiency in entire load conditions for resonant converters, in this paper. Unlike the conventional SR control method where turn-on time of the MOSFETs is varied depending on load conditions due to the stray inductance induced by a lead frame of MOSFET or PCB patterns, the proposed method automatically maintains a time interval between turn-off instance of a MOSFET and zero current instance of a body diode of the MOSFET as a predetermined time, in each switching cycle. Therefore, optimized turn-on time of the MOSFET can be achieved regardless of the leakage inductance. In this paper, the operational principle of proposed control method has been discussed. It has been tested on LLC resonant converter with 240 W to verify the proposed control method.