• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.141-144
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• 2000

Recently DC-DC converters significantly increase the total losses as rising switching frequency. Traditional soft switching technique for reducing switching losses even increase voltage/current stress of switch. In this paper Resonant circuit for soft switching is connected in parallel with power stage and only operates just before turn-on of the main operates just before turn-on of the main switch, Therefore This doesn't affect the total circuit operation. ZNT-PWM converter designed with 170-260V input 4--V 5A output and 100kHz switching frequency is tested respectively with 500W. 1kW, 1.5kW, and 2kW loads.

• 대한전기학회논문지
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• 제37권8호
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• pp.528-533
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• 1988

The miniturization of a DC-to-DC converter in connection with the stability is investigated in this paper. As both the capacitance of the smoothing capacitor and the inductance of the reactor are reduced by rasing the switching frequency, it is known that the stability of the buck converter declines with the switching frequency but the buck-boost converter has a nearly uniform stability. Furthermore, that the buck-boost converter is suitable for the miniturization of circuit is cleared in the high frequency region above a certain switching frequency.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 추계학술발표회
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• pp.39-39
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• 2017

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.824-827
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• 1987

The miniturization of a DC-DC converter circuit in connection with the stability is investigated in this paper. As both the capacitance of the smoothing capacitor and the inductance of the reactor are reduced by raising the switching frequency, it is known that the stability of the buck converter declines with the switching frequency but the buck-boost converter has a nearly uniform stability. Furthermore, that in the frequency region above a certain switching frequency the buck-boost converter is suitable for the miniturization of circuit is cleared.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.946-949
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• 2001

This paper proposes a new zero-current switching (ZCS) pulse-width modulation (PWM) switch cell that has no additional conduction loss of the main switch. In this cell, the main switch and the auxiliary switch turn on and turn off under zero current condition. The diodes commutate softly and the reverse recovery problems are alleviated. The conduction loss and the current stress of the main switch are minimized, since the resonating current for the soft switching does not flow through the main switch. Based on the proposed ZCS PWM switch cell, a new family of dc to dc PWM converters is derived. The new family of ZCS PWM converters is suitable for the high power applications employing IGBTs. Among the new family of dc to dc PWM converters, a boost converter was taken as an example and has been analyzed. Design guidelines with a design example are described and verified by experimental results from the 2.5 kW prototype boost converter operating at 40kHz.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1998년도 학술발표회논문집
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• pp.120-124
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• 1998

In this paper, new zero voltage and zero current switched PWM(Pulse Width Modulated) converters are suggested. The main and auxiliary switch of the converters satisfy soft switching conditions, which are zero voltage or zero current switching of the switches. The switching characteristics of the proposed converters are experimentally verified by boost typed converter, which has 250 kHz switching frequency. For the 250 kHz operation, turn on period of auxiliary switch is about 1/40 for switching period of 4 ${\mu}\textrm{s}$. Therefore, the conduction loss of auxiliary switch is reduced.

• 전기학회논문지P
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• 제62권3호
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• pp.145-150
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• 2013

A novel AC to DC PWM converters with unity input power factor are proposed to overcome the above shortcoming. The main function of these converters is to shape the input line current to force it exactly in phase with the input AC voltage. Therefore, the input power factor can be improved to near unity and the input current harmonics can be eliminated. In this paper, half-bridge converter with two active switches and two diodes are utilized for low-cost type UPS configuration. By having only two semiconductors in the current path at any time, losses can be reduced over the conventional boost topology. Also, this converter provides controllable dc-link voltage, high power factor, and low cost type converter by simple power circuits. Simulation results show that the proposed half-bridge converter/inverter control technique can be applied to single-phase low-cost type UPS systems successfully.

• Journal of Power Electronics
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• 제12권2호
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• pp.258-267
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• 2012

An interleaved single-stage AC/DC converter with a boost converter and an asymmetrical half-bridge topology is presented to achieve power factor correction, zero voltage switching (ZVS) and load voltage regulation. Asymmetric pulse-width modulation (PWM) is adopted to achieve ZVS turn-on for all of the switches and to increase circuit efficiency. Two ZVS half-bridge converters with interleaved PWM are connected in parallel to reduce the ripple current at input and output sides, to control the output voltage at a desired value and to achieve load current sharing. A center-tapped rectifier is adopted at the secondary side of the transformers to achieve full-wave rectification. The boost converter is operated in discontinuous conduction mode (DCM) to automatically draw a sinusoidal line current from an AC source with a high power factor and a low current distortion. Finally, a 240W converter with the proposed topology has been implemented to verify the performance and feasibility of the proposed converter.

• Journal of Power Electronics
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• 제10권4호
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• pp.351-356
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• 2010

A new current-balancing multi-channel LED driver is proposed in this paper. The conventional LED driver system consists of three cascaded power conversion stages and its driver stage has the same number of expensive boost converters as those of the LED channels. On the other hand, the proposed LED driver system consists of two cascaded power stages and its driver stage requires only passive devices instead of expensive boost converters. Nevertheless, all of the currents through multi-channel LEDs can be well balanced. Therefore, it features a smaller system size, improved efficiency, and lower cost. To confirm the validity of the proposed driver, its operation and performance are verified on a prototype for a 46" LCD TV.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.196-197
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• 2010

In same cases of grid connected system using photovoltaic modules, high boosting ratio is required for the converters. Four topologies based on conventional boost converters are implemented according to the voltage doubler and cascade methods. The topologies are analyzed and compared according to its boosting ratio and configurations. Consequently, the suitability of four topologies for MIC application is considered by simulation results.