• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.2
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• pp.64-72
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• 2001

In this paper, forward Zero Voltage Switching Multi Resonant Converter(ZVS MRC) for non-contact charging energy transmission is reposed. The forward ZVS MRC is effective in adsorbing parasitic element as well as minimizing the switching loss. That can accommodate very high frequency. So forward ZVC MRC is applied to non-contact charging energy transmission. Used converter has saperatable transformer and synchronous rectifiers. Coupling coefficient(k), leakage inductance, coupling inductance and resonant frequency are observed for the air gap. By using the observed value, this circuit is designed and implemented. This proposed circuit is simulated by the PSPICE and experimented. The voltage stress of a main switch and the output power of the converter are measured. This paper show that is compatible for non-contact charging energy transmission.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.1
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• pp.56-63
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• 2000

Buck converter is considered to be one of the most widely used DC-DC converters due to its simple structure and high reliable performance. However, when it be combined with thin-film inductor, its own low inductance requires higher switching frequency in order to maintain optimum output ripple voltage and thus gives rise to extra switching losses. In view to overcoming such a technical inconvenience, soft switching fashion is suggested such as zero-voltage-switching of which an well known example is a Zero-Voltage-Switching clamp voltage(ZVS-CV) converter for which low inductance is imperatively required for ZVS operation. In order to support our suggestion, a 1W ZVS-CV buck converter is built by use of thin-film inductor, and then tested it. From the results of experiment and loss analysis, it is proved that the ZVS operation is well achieved and the measured efficiency of the converter is improved about 4% at full load comparing the conventional buck converter.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.4
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• pp.315-322
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• 2009

In the conventional boost converter, the actual duty cycle is limited as the output voltage increases due to increased voltage and current stress of the switch and diode and voltage surge caused by diode reverse recovery. In this paper a new non-isolated boost converter suitable for high gain applications is proposed. The proposed converter has voltage gain of around 6 when the duty cycle is 0.5. Since ZVS is achieved under CCM, the proposed converter has wide ZVS range. Also, voltage ratings of switch and diode are the same as one third of output voltage, and ratings of input and output passive components are reduced due to the interleaving. In addition voltage surge caused by diode reverse recovery is negligible due to ZCS turn-off of diodes. Operating principle of the proposed converter is described and validated through theoretical analysis, simulation and experiment.

• Journal of IKEEE
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• v.16 no.2
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• pp.131-137
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• 2012

This paper is study on a new high efficiency DC-DC converter of discontinuous conduction mode (DCM) with zero voltage switching (ZVS). The converters of high efficiency are generally made that the power loss of the used semiconductor switching devices is minimized. 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. The soft switching operation and the system efficiency of the proposed DCM-ZVS converter are verified by digital simulation and experimental results.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.223-226
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• 2003

This paper presents a high-frequency ZVS-PWM boost chopper-fed DC-DC converter with a single active auxiliary edge-resonant snubber which is used for power conditioner such as solar photovoltaic generation and fuel cell generation. The experimental results of boost chopper fed ZVS-PWM DC-DC converter are evaluated. In audition to its switching voltage and current waveforms, and the switching v-i trajectory of the power devices are discussed and compared with the conventional hard switching DC-DC converter treated here. The temperature performance of IGBT module,, efficiency, and EMI noise characteristics of this ZVS-PWM DC-DC converter using IGBTs are measured and evaluated from an experimental point of view.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.227-230
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• 2003

In this paper, a full bridge edge-resonant zero voltage mode based soft-switching PWM DC-DC power converter with a high frequency center tapped transformer link stage is presented from a practical point of view. The power MOSFETS operating as synchronous rectifier devices are implemented in the rectifier center tapped stage to reduce conduction power losses and also to extend the transformer primary side power MOSFETS ZVS commutation area from the rated to zero-load without a requirement of a magnetizing current. The steady-state operation of this phase-shift PWM controlled power converter is described in comparison with a conventional ZVS phase-shift PWM DC-DC converter using the diodes rectifier. Moreover, the experimental results of the switching power losses analysis are evaluated and discussed in this paper. The practical effectiveness of the ZVS phase-shift PWM DC-DC power converter treated here is actually proved by using 2.5kW-32kHz breadboard circuit. An actual efficiency of this converter is estimated in experiment and is achieved as 97$\%$ at maximum.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2522-2525
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• 1999

Buck converter is considered to be one of the most widely used DC-DC converters due to its simple structure and high reliable performance. However, when it be combined with thin-film inductor, its own low inductance requires higher switching frequency in order to maintain optimum output ripple voltage and thus gives rise to extra switching losses. In view to overcoming such a technical in-convenience, soft switching fashion is suggested such as zero-voltage-switching of which an well known example is a Zero-Voltage-Switching clamp voltage(ZVS-CV) converter for which low inductance is imperatively required for ZVS operation. In order to support our suggestion, a 1W of ZVS-CV buck converter( Vo=3.3V, Iomax=0.3A, fs= 1.2MHz) is built by use of thin-film inductor, and then tested for comparing the measured efficiency between ours and conventional one. As the our results. the efficiency is improved about 2% at full load by the application of our concept.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.2
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• pp.69-74
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• 1999

This paper presents about a example of circuit design and characteristics of proposed circuit in the case of adopted the high frequency resonant Inverter of SEPP type using ZVS(Zero-Voltage-Switching) to the Induction heating load. The soft switching technology known as ZVS is used to reduce turn on and off loss at switching. Also, this paper realizes quantitative circuit analysis which has change the equivalent of Induction heating load to the electric circuit. According to the calculated characteristics value, a method of the circuit designs and operation characteristics of the Inverter is proposed. In addition, this paper proves the propriety of theoretical analysis through the experiment. The proposed inverter shows it can be practically used as power source system for induction heating Jar etc.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.134-139
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• 2005

This paper presents a cost effective quasi-resonant soft-switching PWM high frequency inverter with minimum circuit components. This inverter can achieve wider soft commutation, simpler power circuit configuration, smaller volumetric size, lower cost and wider power regulation range, higher-efficiency as compared with single ended quasi-resonant ZVS-PFM inverter and active voltage clamped quasi-resonant ZVS-PWM inverter. The operation principle of the proposed inverter is described on the basis of the simulation and experimental results, together with its operating performances in steady state. The operating performances of this unique proposed high frequency inverter based on ZVS and ZCS arms-related soft commutation principle is evaluated and discussed as compared with the active voltage-clamped ZVS-PWM inverter and a conventional single-ended ZVS-PFM inverter. The practical effectiveness of a novel type quasi-resonant soft-switching PWM high frequency inverter using IGBT is actually proved for consumer induction heated appliances as rice cooker, hot water producer, steamer and super heated steamer. The extended bidirectional circuit topology of quasi-resonant PWM high frequency inverter with minimum circuit components is demonstrated, which operate as the direct frequency changer.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.5
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• pp.352-357
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• 2000

This paper presents about an example of circuit design and characteristics of inverter according to the variable capacitance of the DC voltage source separation capacitor used in ZVS-HB type high frequency resonant inverter. The soft switching technology known as ZVS is used to reduce turn off loss at switching. In the event the capacitance of the DC voltage source separation capacitor is varied, the analysis of inverter circuit has generally described by using normalized parameter and operating characteristics have been evaluated in terms of switching frequency and parameters. According to the calculated characteristics value, a method of the circuit designs and operating characteristic of the inverter is also presented in this paper. In addition, this paper proves the validity of theoretical analysis through the experiment. This proposed inverter shows that it can be practically used in future as power source system for the lighting equipment of discharge lamp, DC-DC converter etc.