• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.174-176
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• 2003

The power conversion system must be increased switching frequency in order to achieve a small size, a light weight and a low noise. This paper proposes a skillful and a concise PWM DC-DC converter employing both zero voltage and zero current high frequency switching(ZVCS) operation. The Proposal ZVCS circuit is composed with resonant circuit using active resonant condenser. And this circuit provides switches with ZVS and ZCS by quasi resonant only that switching transients appear. This operation results in reduction of stress and losses in the power devices and resonant components. Some simulation results are included to confirm the validity of the analytical results.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.189-192
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• 2001

This paper proposed that an AC-DC converter system using multiple buck-chopper operates with four choppers connecting to a number of parallel circuits. To improve these, a large number of soft switching topologies included a resonant circuit have been proposed. And, some simulative results on computer are included to confirm the validity of the analytical results. The partial resonant circuit makes use of an inductor using step-down and a condenser of loss-less snubber. The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in a partial resonant circuit makes charging energy regenerated at input power source for resonant operation. The proposed conversion system is deemed the most suitable for high power applications where the power switching devices are used.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.294-298
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• 2003

In this paper, the new zero-current-transition (ZCT) circuit cell is proposed. The main switch is turned-off under the zero current and zero voltage condition, and there is no additional current stress and voltage stress in, the main switch and the main diode. The Auxiliary switch is turned-off under the zero voltage condition, and the main diode is turned-on under the zero voltage condition, The resonant current required to obtain the ZCT is small and regenerated to the input voltage source. The operational principles of the boost converter integrated with the proposed ZCT circuit cell is analyzed theoretically and verified by the simulation and experimental result. Index terms - zero-current-transition (ZCT), zero-current- switching (ZCS), zero-voltage-switching (ZVS)

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1992.11a
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• pp.47-50
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• 1992

In this paper, the authors propose a so-called new zero voltage switching circuit topology arts an improved PWM strategy. In order to minimize voltage stress in dc-ac high switching frequency power conversion, the proposal circuit is used as interface between DC sully and the PWM inverter. The new ZVS circuit provide PWM inverter with a short zero voltage period in the dc 1ink just before inverter switches operate. By using the proposed modulating signal (transformational sinewave) art carrier sinal (sawtooth ware), the amplitude of the fundamental component is increased about 15 percent more than that of a conventional sinusoidal modulating signal and triangular carrier signal, the switching tosses is reduced. Some simulative results on computer are included to confirm the validity of the analytical results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.357-360
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• 2008

In this paper a high efficiency soft switching boost converter is proposed for photovoltaic system. Using some resonant components, the circuit can be achieved the soft switching capability. Each of the switches in the proposed circuit performs ZV (Zero Voltage) or ZC (Zero Current) switching. Thus, the high efficiency characteristic can also be obtained, and then the size of the total system can be reduced. The operational modes of the verifying the effectiveness of the proposed circuit. As a matter of course, we will present the simulation results in this paper.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.487-488
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• 2010

This paper proposes a soft switching boost converter with an auxiliary circuit. This circuit helps a main switch operate as a soft switching. The main switch operates ZVS turn-on and ZVS turn-off. And the auxiliary switch operates ZCS turn-on and ZVS turn-off. In this paper, operation modes are analyzed and soft switching operation is verified through simulations.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.12
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• pp.664-669
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• 2002

In this paper the method to determine tire optimal switching instants in order to reduce the transient surges during switching not relevant to the neutral treatment of shunt reactors is presented. This method consists of the following two steps. First, the instants of the voltage peaks between the contacts of each poles and the voltage magnitude as well as the moments of the current zero crosses were found out analytically. Next, the instants of the contact touches or separations were determined in consideration of the rate of decrease of dielectric strength or a circuit breaker and the variation of the its operating time. The results obtained from the EMTP(Electromagnetic Transient Program) analysis studies show that the making instants are established at the peak voltage of each three poles for any conditions of a neutral point and the possible upper limited values of inrush currents due to the variation of the mechanical operating time can be estimated.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.38-40
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• 2002

In the case of conventional high frequency inverter, with damage of switch by surge voltage when switch gets into compulsion extinction by load accident and so on because reactor is connected by series to switch, or there was problem of conduction loss by reactor's resistivity component, Also, it has controversial point of that can not ignore conduction loss of switch in complete work kind action of soft switching. In this paper, as high frequency induction heating power supply, we propose half bridge type multi resonance soft switching high frequency inverter topology that can realize high amplitude operation of load current with controlling switch current by multiplex resonance, mitigating surge voltage when switch gets into compulsion extinction and to be complete operation of zero current switching by opposit parallel connected reactor to inverter switch. and do circuit analysis for choice of most suitable circuit parameter of circuit

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.185-187
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• 1995

A boost converter proposed in this paper operates with high power factor due to input current of sinusoidal waveform. If there were no input LPF, the current is got to be discontinuos form in proportion to AC input voltage magnitude under the constant duty factor switching. Thereupon, the harmonics of input current waveform is reduced and the LPF is made with few elaboration and the control circuit is simple. The switching devices in proposed circuit are operated with soft switching by the partial resonant method. The patial resonant circuit makes use of a reactor using step-up and a capacitor of loss-less snubber. The result is that switching loss is very low and efficiency of system is high.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.18-24
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• 2019

In this paper, expandable bobbin type multiple integrated coupled-inductor applied 4-paralled switching rectifier was proposed. To design the proposed inductor easily, inductance designing formula was derived through magnetic circuit analysis of the 4-paralleled integrated coupled-inductor. Furthermore, to verify practicality of the proposed inductor, it was applied in 600W class 4-paralleled interleaved switching rectifier, and the steady-state characteristics of the proposed inductor and discrete inductors were compared. Consequently, it was showed that the proposed inductor can replace the conventional discrete inductors with alternative electrical characteristic standard, hence miniaturization of the SMPS can be achieved. From the test result, test circuit with the proposed inductor showed maximum 97.1% of power conversion efficiency and under 18W of power loss where the circuit with discrete inductors showed 96.7% and 20W respectively.