• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.4
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• pp.273-280
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• 2018

This paper proposes a zero-voltage-transition pulse-width modulation (PWM) DC-DC converter that uses a new active-snubber-cell. The converter main switch can be turned on and off with ZVS, while the snubber switch is turned on with ZCS and turned off with ZVS. Other semiconductor devices are operated under the soft-switching condition. Normal PWM control can be used, the proposed active-snubber-cell does not impose any additional voltage and current stresses. The active-snubber-cell is suitable for high-power applications due to its easy integration into interleaved converters. This paper discusses the operation of the converter, presents some design guidelines, and provides the results of an experiment with a 100 kHz and 1 kW prototype. A peak efficiency of 97.8% is recorded.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.289-290
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• 2012

This paper proposes a new active snubber boost PFC converter to provide a zero-voltage-switching (ZVS) turn-on condition and reduce electromagnetic interference (EMI) noise in home appliances and renewable energy applications, including solar or fuel cell electric systems. The proposed active snubber circuit enables a main boost switch of the boost-type PFC or grid converter to turn on under a ZVS condition and reduce the switching losses of the main boost switch. Moreover, for the purpose of a specialized intelligent power module (IPM) fabrication, the proposed boost circuit is designed to satisfy some design aspects such as space saving, low cost, and easy fabrication. Simulation and experimental results of a 2kW IPM boost-type PFC converter are provided to verify the effectiveness of the proposed active snubber boost circuit.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1592-1601
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• 2014

In this study, a novel single phase soft switched power factor correction (PFC) converter is developed with active snubber cell. The active snubber cell provides boost switch both to turn on with zero voltage transition (ZVT) and to turn off with zero current transition (ZCT). As the switching losses in the proposed converter are too low, L and C size can be reduced by increasing the operating frequency. Also, all the semiconductor devices operate with soft switching. There is no additional voltage stress in the boost switch and diode. The proposed converter has a simple structure, low cost and ease of control as well. It has a simple control loop to achieve near unity power factor with the aid of the UC3854. In this study, detailed steady state analysis of the proposed converter is presented and this theoretical analysis is verified by a prototype of 100 kHz and 500 W converter. The measured power factor and efficiency are 0.99 and 97.9% at full load.

• Journal of Power Electronics
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• v.4 no.1
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• pp.46-55
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• 2004

This paper presents a high-frequency ZVS-PWM boost chopper-fed DC-DC converter with a single active auxiliary edge resonant snubber in the load-side which can be designed for power conditioners such as solar photovoltaic generation, fuel cell generation, battery and super capacitor energy storages. Its principle operation in steady-state is described in addition to a prototype setup. The experimental results of ZVS-PWM boost chopper-fed DC-DC converter proposed here, are evaluated and verified with a practical design model in terms of its switching voltage and current waveforms, the switching v-i trajectory, the temperature performance of IGBT module, the actual power conversion efficiency and the EMI of radiated and conducted emissions. And then discussed and compared with the hard switching scheme from an experimental point of view. Finally, this paper proposes a practical method to suppress parasitic oscillation due to the active auxiliary resonant switch at ZCS turn off mode transition with the aid of an additional lossless clamping diode loop, and reduced the EMI conducted emission in this paper.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.4
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• pp.351-355
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• 2016

Welding machines are high-capacity systems used in a low-frequency range using IGBT. As their system is similar to a large transformer, most welding machines suffer a great loss because of hard switching and vast leakage inductance. A voltage-balancing circuit is designed to overcome these shortcomings. This circuit can reduce the transformer size by making it into a high frequency and reducing the input voltage by half and by adopting a serial structure that connects two full-bridges in a series to use a MOSFET with a good property at high frequency. In addition, a Schottky diode is used in the primary rectifier to overcome the low efficiency of most welding machines. To use the Schottky diode with a reliably relatively low withstanding voltage, an active snubber is adopted to effectively limit the ringing voltage of the diode cut-off voltage.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.7
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• pp.7-15
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• 2008

A single active capacitor snubber-assisted soft-switching sinewave pulse modulation utility-interactive power conditioner with a three-winding flyback high frequency transformer link and a bidirectional active power switch in its secondary side has been proposed. With the aid of the switched-capacitor quasi-resonant snubber cell, the high frequency switching devices in the primary side of the proposed DC-to-AC sinewave power inverter can be turned-off with ZVS commutation. In addition to this, the proposed power conditioner in the DCM can effectively take the advantages of ZCS turn-on commutation. Its output port is connected directly to the utility AC power source grid. At the end, the prototype of the proposed HF-UPC is built and tested in experiment. Its power conversion conditioning and processing circuit with a high frequency flyback transformer link is verified and the output sinewave current is qualified in accordance with the power quality guidelines of the utility AC interactive power systems.

• Journal of Power Electronics
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• v.7 no.2
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• pp.109-117
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• 2007

In this paper, a novel proposal for a utility-interactive three-phase soft commutation sinewave PWM power conditioner with an auxiliary active resonant DC-link snubber is developed for fuel cell and solar power generation systems. The prototype of this power conditioner consists of a PWM boost chopper cascaded three-phase power conditioner, a single two-switch auxiliary resonant DC-link snubber with two electrolytic capacitors incorporated into one leg of a three-phase V-connection inverter and a three-phase AC power source. The proposed cost-effective utility-interactive power conditioner implements a unique design and control system with a high-frequency soft switching sinewave PWM scheme for all system switches. The operating performance of the 10 kW experimental setup including waveform quality, EMI/RFI noises and actual efficiency characteristics of the proposed power conditioner are demonstrated on the basis of the measured data.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.3
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• pp.147-154
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• 2003

This paper presents a high-frequency boost type ZVS-PWM chopper-fed DC-DC power converter with a single active auxiliary edge-resonant snubber at the load stage which can be designed for power conditioners such as solar photovoltaic generation, fuel cell generation, battery and super capacitor energy storages. Its principle operation in steady-state is described in addition to a prototype setup. The experimental results of boost type ZVS-PWM chopper proposed here, are evaluated and verified with a practical design model in terms of its switching voltage and current waveforms, the switching v-i trajectory and the temperature performance of IGBT module, the actual power conversion efficiency, and the EMI of radiated and conducted emissions, and then discussed and compared with the hard switching scheme from an experimental point of view. Finally, this paper proposes a practical method to suppress parasitic oscillation due to the active auxiliary resonant switch at ZCS turn-off mode transition with the aid of an additional lossless clamping diode loop, and can be reduced the EMI conducted emission.

• 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.

• Journal of Power Electronics
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• v.17 no.1
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• pp.41-55
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• 2017

This study proposes a novel zero voltage transition (ZVT) pulse width modulation (PWM) DC-DC interleaved boost converter with an active snubber cell. All the semiconductor devices in the converter turn on and off with soft switching to reduce the switching power losses and improve the overall efficiency. Through the interleaved approach, the current stresses of the main devices and the ripple of the output voltage and input current are reduced. The main switches turn on with ZVT and turn off with zero voltage switching (ZVS). The auxiliary switch turns on with zero current switching (ZCS) and turns off with ZVS. In addition, the snubber cell does not create additional current or voltage stress on the main switches and main diodes. The proposed converter can smoothly achieve soft switching characteristics even under light load conditions. The theoretical analysis and operating stages of the proposed converter are made for the D > 50% and D < 50% modes. Finally, a prototype of the proposed converter is implemented, and the experimental results are given in detail for 500 W and 50 kHz. The overall efficiency of the proposed converter reached 95.5% at nominal output power.