• Journal of Power Electronics
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• v.13 no.2
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• pp.177-185
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• 2013

This paper studies a soft switching DC/DC converter to achieve zero voltage switching (ZVS) for all switches under a wide range of load condition and input voltage. Two three-level PWM circuits with the same power switches are adopted to reduce the voltage stress of MOSFETs at $V_{in}/2$ and achieve load current sharing. Thus, the current stress and power rating of power semiconductors at the secondary side are reduced. The series-connected transformers are adopted in each three-level circuit. Each transformer can be operated as an inductor to smooth the output current or a transformer to achieve the electric isolation and power transfer from the input side to the output side. Therefore, no output inductor is needed at the secondary side. Two center-tapped rectifiers connected in parallel are used at the secondary side to achieve load current sharing. Due to the resonant behavior by the resonant inductance and resonant capacitance at the transition interval, all switches are turned on at ZVS. Experiments based on a 1kW prototype are provided to verify the performance of proposed converter.

• Journal of information and communication convergence engineering
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• v.6 no.3
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• pp.301-304
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• 2008

This paper presents a lossless inductor snubber-assisted series resonant high frequency inverter using the trench gate IGBTs for the electromagnetic induction eddy current-heated fixing roller in copy and printing machines in a new generation. This soft switching high-frequency inverter can completely achieve zero current soft switching (ZCS) commutation mode transitions and wide power regulation under its constant frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally presented for a constant frequency PDM strategy under a ZCS operation, together with its output power regulation characteristics-based on the pulse density modulation. The effectiveness of this soft switching high-frequency inverter is confirmed for the fixing equipment with the induction-heated fixing roller.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.1
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• pp.14-21
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• 2006

This paper presents a Zero-Current Switching(ZCS) two-transformer phase-shifted full-bridge(TTFB) converter using voltage ripple. The proposed converter provides Zero-Voltage Switching(ZVS) of leading leg switches and ZCS of lagging leg switches using voltage ripple. Especially, circulating current is reduced by ZCS operation and there are no additional components required for the soft switching of power switches. Furthermore, in case of light load, ZVS operation of lagging leg can be achieved. The operations, analysis and design consideration of proposed converter are presented. To verify the validity of the proposed converter, experimental results for a 410W (205[V], 2[A]) prototype are presented.

• Journal of the Korea Computer Industry Society
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• v.8 no.2
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• pp.107-112
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• 2007

Laser wave length can have evaporation effect by absorption because outer skin or tissue of focus is consisted of water almost though absorption of water occurs more than 90% almost in formation thickness of very thin floor. Can operate outer skin, steam by floor and correct incision of formation is available. Suture surgical operation is available to vein or lymph system and surgical operation region can dry and see as eye and radish bleeding surgical operation is available. Specially, stability of tube both end output about pulse by weight very, this research can cause various curative effect because can reduce bulk and control easily current wave style of medical laser using electric power conversion device of high frequency way. If introduce ZVS (Zero Voltage Switching) or ZVZCS (Zero Voltage and Zero Current Switching), is more profitable because can reduce switching damage. Because electric power department of proposed medical laser can do stable soft-switching in wide subordinate extent introducing ZVZCS technique by the first help and control department composes microcontroller, output current waveform user have free form make Result that experiment because design and manufacture, brought result that improve of 20% than existing equipment, and will be bought to get into superior result if supplement as systematic late.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1103-1104
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• 2008

In this paper, authors propose a novel step-up AC-DC chopper operated with power factor correction (PFC) and with high efficiency. The proposed chopper behaves with discontinuous current control (DCC) of input current. The input current waveform in the proposed chopper is got to be a discontinuous sinusoid form in proportion to magnitude of ac input voltage under the constant duty cycle switching. Therefore, the input power factor is nearly unity and the control method is simple. In the general DCC chopper, the switching devices are turned-on with the zero current switching, but turn-off of the switching devices is switched at current maximum value. To achieve a soft switching of the switching turn-off, the proposed chopper is used a new partial resonant circuit. The result is that the switching loss is very low and the efficiency of chopper is high.

• Proceedings of the KIPE Conference
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• 2001.12a
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• pp.129-132
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• 2001

Recently, a ZVT boost converter is embedded in a power factor correction system. The control circuit of the converter assures soft-switching for all the MOSFETs and load regulation. The PFC system contains additional control circuits which assure the input voltage in a sinusoidal form and feed-forward line voltage regulation. In this paper, a soft switching boost converter with zero-voltage transition(ZVT) main switch using zero-current switching(ZCS) auxiliary switch is proposed. Operating intervals of the converter are persented and analyzed. The proposed results show that the main switch maintains UT while auxiliary switch retains ZCS for the complete specified line and load conditions.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.39-42
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• 1998

This paper is presented the Partial Resonant Soft Switching Mode Power Converter which is adapted the power converter having the partial resonant soft switching mode, that makes switches operated when the resonant current or voltage becomes zero by making the resonant circuit partially at turning on and off of the switches with suitable layout of the resonant elements and switch elements in the converter. Also, this paper includes the analysis and simulation of the Partial Resonant type Buck-Boost Chopper.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.668-672
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• 2001

The utility interactive sinewave modulated inverter for the solar photovoltaic (PV) power conversion and conditioning with a new high frequency pulse modulated link is presented for domestic residential applications. As compared with the conventional full-bridge hard switching PWM inverter with a high frequency AC link, the simplest single-ended quasi-resonant soft switching sinewave modulated inverter with a duty cycle pulse control is implemented, resulting in size and weight reduction and low-cost. This paper presents a prototype circuit of the single-ended zero voltage soft switching sinewave inverter for solar power conditioner and its operating principle. In addition, this paper proposes a control system to deliver high quality output current. Major design of each component and the power loss analysis under actual power processing is also discussed from an experimental point of view. A newly developed interactive sinewave power processor which has $92.5\%$ efficiencty at 4kW output is demonstrated. It is designed 540mm-300mm-125mm in size, and 20kg in weight.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.1
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• pp.80-85
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• 2015

In the issues of interleaved topology which have been in limelight as high power converter, various soft-switching methods are studied to reduce switching losses in high power application. The interleaved ZCT converter has an additional filter inductor to reduce losses of diodes during reverse recovery process. However, additional current conduction modes are occurred by the inductor, we need to analyze switching losses with inductor values on each mode. In this paper, current conduction modes and boundary conditions of interleaved ZCT converter are analyzed. In the conclusion, the minimum of switching losses in converter operation modes is analyzed by calculating switching losses.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.15-16
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• 2012

This paper is study on a novel high efficiency step up-down converter using loss-less snubber capacitor. The proposed converter is accomplished that the turn-on operation of switches is on zero current switching (ZCS) by DCM. The converter is also applicable to a new quasi-resonant circuit to achieve high efficiency converter. The control switches using in the converter are operated with soft switching, that is, ZVS and ZCS by quasi-resonant method. The control switches are operated without increasing their voltage and current stresses by the soft switching technology. The result is that the switching loss is very low and the efficiency of the converter is high.