• 전력전자학회논문지
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• 제23권3호
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• pp.190-198
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• 2018

This paper proposes a nonisolated, bidirectional, soft-switching DC - DC converter with PWM plus phase shift (PPS) control. The proposed converter has an input-parallel/output-series configuration and can achieve the interleaving effect and high voltage gains, resulting in decreased voltage ratings in all related devices. The proposed converter can operate under zero-voltage switching (ZVS) conditions for all switches in continuous conduction mode. The power flow of the proposed converter can be controlled by changing the phase shift angle, and the duty is controlled to balance the voltage of four high voltage side capacitors. The PPS control device of the proposed converter is simple in structure and presents symmetrical switching patterns under a bidirectional power flow. The PPS control also ensures ZVS during charging and discharging at all loads and equalizes the voltage ratings of the output capacitors and switches. To verify the validity of the proposed converter, an experimental investigation of a 2 kW prototype is performed in both charging and discharging modes under different load conditions and a bidirectional power flow.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.256-262
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• 2018

This study introduces a novel Soft Switching (SS) Pulse Width Modulated (PWM) AC-DC boost converter. In the proposed converter, the main switch is turned on with Zero Voltage Transition (ZVT) and turned off with Zero Current Transition (ZCT). The main diode is turned on with Zero Voltage Switching (ZVS) and turned off with Zero Current Switching (ZCS). The auxiliary switch is turned on and off with ZCS. All auxiliary semiconductor devices are turned on and off with SS. There is no extra current or voltage stress on the main semiconductor devices. The majority of switching energies are transferred to the output by auxiliary transformer. Thus, the current stress of auxiliary switch is significantly reduced. Besides, the proposed converter has simple structure and ease of control due to common ground. The theoretical analysis of the proposed converter is verified by a prototype with 100 kHz switching frequency and 500 W output power. Furthermore, the efficiency of the proposed converter is 98.9% at nominal output power.

• Smart Structures and Systems
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• 제25권3호
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• pp.385-391
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• 2020

In this paper, a new passive lossless snubber circuit with energy transfer capability is proposed. The proposed lossless snubber circuit provides Zero-Current Switching (ZCS) condition for turn-on instants and Zero-Voltage Switching (ZVS) condition for turn-off instants. In addition, its diodes operate under soft switching condition. Therefore, no significant switching losses occur in the converter. Since the energy of the snubber circuit is transferred to the output, there are no significant conduction losses. The proposed snubber circuit can be applied on isolated and non-isolated converters. To verify the operation of the snubber circuit, a boost converter using the proposed snubber is implemented at 70W. Also, the measured conducted Efficiency Electromagnetic Interference (EMI) of the proposed boost converter and conventional ones are presented which show the effects of proposed snubber on EMI reduction. The experimental results confirm the presented theoretical analysis.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제4B권3호
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• pp.127-133
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• 2004

This paper presents a prototype of three-phase current source zero voltage soft-switching PWM controlled PFC rectifier with Single Active Auxiliary Resonant Commutated Snubber (ARCS) circuit topology. The proposed three-phase PFC rectifier with sinewave current shaping and unity power factor scheme can operate under a condition of Zero Voltage Soft Switching (ZVS) in the main three phase rectifier circuit and zero current soft switching (ZCS) in auxiliary snubber circuits. The operating principle and steady-state performances of the proposed three-phase current source soft-switching PWM controlled PFC rectifier controlled by the DSP control implementation are evaluated and discussed on the basis of the experimental results of this active rectifier setup.

• Journal of Power Electronics
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• 제16권3호
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• pp.894-904
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• 2016

This study examines the zero-voltage switching (ZVS) operation of an active-clamped forward converter (ACFC) with a current-doubler rectifier (CDR). The ZVS condition can be obtained with a much smaller leakage inductance compared to that of a conventional ACFC. Due to the significantly reduced leakage inductance, the design is optimized and the circulating loss is reduced. The operation of the ACFC with a CDR is analyzed, and a detailed ZVS analysis is conducted on the basis of a steady-state analysis. From the results, a design consideration for ZVS improvement is presented. Loss analyses of the converters shows that enhanced soft-switching contributes to an efficiency improvement under light-load condition. Experimental results from a 100-W (5-V/20-A) prototype verify that the ACFC with a CDR can attain ZVS across an extended load range of loads and achieve a higher efficiency than conventional ACFCs.

• Journal of Power Electronics
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• 제16권5호
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• pp.1639-1649
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• 2016

This paper presents a family of soft-switching DC-DC converters with a simple auxiliary circuit consisting of a coupled winding and a pair of auxiliary switch and diode. The auxiliary circuit is activated in a short interval and thus the circulating conduction losses are small. With the auxiliary circuit, zero-voltage-switching (ZVS) and zero-current-switching are achieved for the main and auxiliary switches respectively, over wide input voltage range and load variation. In addition, the reverse-recovery problem of diodes is significantly alleviated because of the leakage inductor. Furthermore, the coupled inductor simultaneously serves as the main and auxiliary inductors, contributing to reduced magnetic component in comparison with the conventional zero-voltage-transition (ZVT) converters. Experimental results based on a 500 W prototype buck circuit validate the advantages and effectiveness of the proposed magnetic coupling ZVS converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.438-439
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• 2011

In this paper, soft switching bidirectional DC-DC converter is proposed. The proposed topology is added two auxiliary switches, two resonant capacitors and one resonant inductor to convectional bidirectional DC-DC converter. Therefore, this proposed topology can reduce switching loss of each power switch by ZVS (Zero Voltage Switching) and ZCS (Zero Current Switching). We have performed mode analysis, simulation and experiment for the proposed topology.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.210-213
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• 1991

The clamp mode Zero-Volatge-Switched Multi-Resonant-Converter(ZVS-MRC) is proposed. In the converter, the performance of the conventional ZVS-MRC is improved by clamping the drain-to-source voltage of the power switch using a soft switching nondissipative active clamp network. The analysis for each stage of the converter operation modes is presented and is verified by experiments.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1835-1841
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• 2017

An improved single-phase full-bridge zero-voltage-switching inverter using a subtractive coupled magnetics is proposed in this paper. The proposed topology overcomes several drawbacks of the conventional ARCPI zero-voltage-switching inverter including two bulky capacitors which can cause problems such as the need for a protection circuit and voltage fluctuation of split capacitors. Also the proposed topology can reduce the number of devices required for ZVS through a simplified auxiliary circuit, thus achieving low cost and small volume and is applicable a modified unipolar PWM scheme. Detail mode analysis and design considerations are provided for optimal efficiency. In the end, the effectiveness and feasibility of the proposed topology are verified experimentally under various conditions.

• Journal of Power Electronics
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• 제3권4호
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• pp.239-248
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• 2003

This paper presents a novel prototype of three-phase voltage source type zero voltage soft-switching inverter with the auxiliary resonant snubbers suitable for high-power applications with IGBT power module packages in order to reduce their switching power losses as well as electromagnetic conductive and radiative noises. A proposed single inductor-assisted resonant AC link snubber circuit topology as one of some auxiliary resonant commutation snubbers developed previously to achieve the zero voltage soft-switching (ZVS) for the three-phase voltage source type sinewave PWM inverter operating under the instantaneous space voltage vector modulation is originally demonstrated as compared with the other types of resonant AC link snubber circuit topologies. In addition to this, its operation principle and unique features are described in this paper. Furthermore, the practical basic operating performances of the new conceptual instantaneous space voltage vector modulation resonant AC link snubber-assisted three-phase voltage source type soft-switching PWM inverter using IGBT power module packages are evaluated and discussed on the basis of switching voltage and current waveforms, output line to line voltage quality, power loss analysis, actual power conversion efficiency and electromagnetic conductive and radiative noises from an experimental point of view, comparing with those of conventional three-phase voltage source hard-switching PWM inverter using IGBT power modules.