• 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)

• Journal of Power Electronics
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• v.3 no.4
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• pp.215-223
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• 2003

In this paper, a 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, respectively. 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 condition is relatively small and regenerated to the input voltage source. The operational principles of a boost converter integrated with the proposed ZCT circuit cell are analyzed and verified by the simulation and experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.2
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• pp.79-85
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• 2001

In this paper, a novel Zero-Current-Transition (ZCT) technique, which provides Zero-Current-Switching (ZCS) turn-off of the main switch, the main diode and the auxiliary switch, is presented. The proposed auxiliary circuit consists of minimum elements only one auxiliary switch, resonant inductor and resonant capacitor. Also the reduced di/dt, which is obtained by resonant inductor, helps soft turn-on of the main switch. Besides, to eliminate the additional conduction loss and current stress on main switch, a topological variation was performed. The theoretical analysis and the operation principle of the new ZCT techniques are described in detail with a boost converter as an example. To verify the validity of the proposed ZCT techniques, the simulation and the experiment were performed under 1kW output power and 100kHz switching frequency.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1669-1677
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• 2016

A new auxiliary circuit for boost, buck, buck-boost, Cuk, SEPIC, and zeta converters is introduced to provide soft switching for pulse-width modulation converters. In the aforementioned family of DC-DC converters, the main and auxiliary switches turn on under zero current transition (ZCT) and turn off with zero voltage and current transition (ZVZCT). All diodes commutate under soft switching conditions. On the basis of the proposed converter family, the boost topology is analyzed, and its operating modes are presented. The validity of the theoretical analysis is justified by the experimental results of a 100W, 100 kHz prototype. The conducted electromagnetic emissions of the proposed boost converter are measured and found to be lower than those of another ZCT boost converter.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.950-952
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• 2001

This paper proposes a new zero-current transition (ZCT) pulse-width modulation (PWM) switch cell that overcomes the limitations of the conventional ZCT converters. The proposed ZCT cell provides zero-current-switching (ZCS) condition for the main switch and the auxiliary switch. The conduction loss and current stress of the main switch are minimized, since the circulating current for the soft switching does not flow through the main switch. The proposed ZCT PWM switch cell is suitable for the high power applications employing IGBTs. Design guidelines with a design example are described and verified by experimental results from the 1 kW prototype boost converter operating at 70kHz.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.213-215
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• 2002

This paper presents grid connected photovoltaic inverter system using a new Zero-Current-Transition(ZCT) technique. The main switches of the proposed grid connected inverter are turned off under the zero current condition by operating the auxiliary circuit and also all semiconductor devices, switches and diodes, are applied to low rated voltage regardless of the load condition. In additionally, the proposed ZCT scheme has advantages, which are without the additional current stresses and the conduction losses on the main switches during the resonance period of the auxiliary circuit. The simulation was performed to verify the validity of the proposed grid connected photovoltaic ZCT inverter system.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.217-219
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• 2005

This paper presents an improved ZCT (Zero-Current-Transition) PWM DC/DC Boost Converter without additional current stress and conduction loss on the main switch during the resonance period of the auxiliary cell. The auxiliary cell consists of a resonance inductor, a resonant capacitor, an auxiliary switch and the Zero-Current-Switching ranges of the main and the auxiliary switch of the proposed converters are entirely achieved by operating the auxiliary cell. Then Improved ZCT soft switching converter will be discussed. Therefore, the proposed converter has a high efficiency. To show the superiority of this converter is verified through the experiment with a 640W, 50kHz prototype converter.

• Journal of Power Electronics
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• v.9 no.2
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• pp.156-163
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• 2009

In this paper a family of zero current transition PWM converters which employs a simple auxiliary circuit is introduced. This soft switched auxiliary circuit is only composed of a switch and a capacitor. The proposed converters are analyzed and various operating modes of the ZCT flyback converter are discussed. Design considerations are presented and the experimental results of the ZCT flyback converter laboratory prototype are illustrated. The experimental results confirm the validity of theoretical analysis.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1539-1548
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• 2018

This paper introduces a new soft switched AC-DC boost converter with power factor correction (PFC). In the introduced converter, all devices are turned on and off under soft switching (SS). The main switch is turned on under zero voltage transition (ZVT) and turned off under zero current transition (ZCT). The main diode is turned on under zero voltage switching (ZVS) and turned off under zero current switching (ZCS). Meanwhile, there is not any current or voltage stress on the main devices. Besides, the auxiliary switch is turned on under ZCS and turned off under ZVS. The detailed theoretical analysis of the converter is presented, and also theoretical analysis is verified by a prototype with 100 kHz and 500 W. Also, the proposed converter has 99.8% power factor and 97.5% total efficiency at soft switching operation.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.759-762
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• 2002

A ZCT(Zero Current Transition) PWM(Pulse-Width-Modulation) boost converter using parallel MOSFET switch is proposed in this paper. The IGBT(main switch) of the proposed converter is always turned on with zero current switching and turned off with zero current/zero voltage switching. The MOSFET(auxiliary switch) is also operates with soft switching condition. In addtion to, the proposed converter eliminates the reverse recovery current of the freewheeling diode by adding the resonant inductor, Lr, in series with the main switch. Therefore, the turn on/turn off switching losses of switches are minimized and the conduction losses by using IGBT switch are reduced. In addition to, using parallel MOSFET switch overcomes the switching frequency limitation occurred by current tail. As mentioned above, the characteristics are verified through experimental results.