• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.379-381
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• 1995

Many new electronic products are required to have a near unity power factor and a distortion free input current waveform. In this paper, a high performance single phase PWM AC/DC converter with input power factor correction is proposed. This proposed control strategy has many advantages which include one semiconduction switch, simplified control circuit, high performance features and continuous input current. The experimental results are included to verify the validity of this approach.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.387-390
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit Incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.709-712
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• 1998

A new ZVS-CV PWM converter with power factor correction (PFC) function is presented in this paper. The new topology is a integration of a boost converter and a ZVS-CV topology in a single power conversion stage. The new converter can be regulated in pulse-width modulation (PWM) by universal integrated control circuits. Some design considerations are given in detail. A laboratory prototype has been implemented to show the feasibility of the approach and the analysis.

• Journal of Electrical Engineering and Technology
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• v.5 no.3
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• pp.477-483
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• 2010

This paper is studied on a novel buck-boost isolated converter for high efficiency and high power factor. The switching devices in the proposed converter are operated by soft switching technique using a new quasi-resonant circuit, and are driven with discontinuous conduction mode (DCM) according to pulse width modulation (PWM). The quasi-resonant circuit makes use of a step up-down inductor and a loss-less snubber capacitor. The proposed converter with DCM also simplifies the requirement of control circuit and reduces a number of control components. The input ac current waveform in the proposed converter becomes a quasi sinusoidal waveform in proportion to the magnitude of input ac voltage under constant switching frequency. As a result, it is obtained by the proposed converter that the switching power losses are low, the efficiency of the converter is high, and the input power factor is nearly unity. The validity of analytical results is confirmed by some simulation results on computer and experimental results.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.2
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• pp.104-111
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• 1997

In this paper, three-phase PWM AC to DC boost converter that operates with unity power factor and sinusodial input line currents is presented. The current control of this converter is based on the space vector PWM strategy with fixed switching frequency and the line currents track to reference currents within one sampling time interval. By using this control strategy low ripples in the outut current and the voltage as well as fast dynamic response are achieved with small dc link cpacitance employed.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.117-120
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• 1998

This paper proposes a new high efficiency single-phase AC-DC boost converter for power factor correction. Lossless commutation circuit is interposed in the proposed converter for soft-switching. Due to this commutation circuit, the converter operates in 9 mode. In spite of changing input voltage and load, It attracts a constant DC output voltage because of the PWM control scheme using both the output voltage feedback and the input voltage feedforward. The converter is suitable for high power applications and operates in continuous conduction mode. In this paper, a 2.4[kW] converter is designed and simulated.

• Journal of Fisheries and Marine Sciences Education
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• v.9 no.2
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• pp.209-221
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• 1997

This paper presents a soft switching unity power factor PWM rectifier, which features reduced conduction losses and soft switching with no auxiliary switches. The soft switching are achieved by using a simple commutation circuit with no auxiliary switches, and reduced conduction loses are achieved by employing a single converter, instead of a typical front end diode rectifier followed by a boost rectifier. Furthermore, thanks to good features such as simple PWM control at constant frequency, low switch stress and low VAR rating of commutation circuits, it is suitable for high power applications. The principle of operation is explained in detail, and major characteristics analysis and experimental results of the new converter also included.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.25-33
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• 1999

In this paper, the method of reducing hanmnics and correcting of power factor in single PWM converter associated with diode rectifier and boost converter is studied. In the general diode rectifier there are sorre problems that discontinuous current of reducing power factor and including distortion of hanmnics at the input current affects other sources. To solve the problems of performance degradation due to pulse wavefonn in the input current, the ac-dc converter in which the hanmnic distortion in the input current is reduced using a third-hanmnic-injected PWM is proposed. A lower power loss of switching and easy configuration of circuit are obtained by adopting discontinuous current mode. Simulation and experimental results of ac-dc converter with 5[kHz] switching frequency are presented and correction of power factor and reduction of total hanmnic distortion was established.lished.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.203-205
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.54-63
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• 2007

Recently, a fuel cell with low voltage and high current output characteristics is remarkable for new generation system. It needs both a DC-DC step-up converter and DC-AC inverter to be used in fuel cell generation system. Therefor, this paper, consists of an isolated DC-DC converter to boost the fuel cell voltage $380[V_{DC}]$ and a PWM inverter with LC filter to convent the DC voltage to single-phase $220[V_{AC}]$. Expressly, a tapped inductor filter with freewheeling diode is newly implemented in the output filter of the proposed high frequency isolated ZVZCS PWM DC-DC converter to suppress circulating current under the wide output voltage regulation range, thus to eliminate the switching and transformer turn-on/off over-short voltage or transient phenomena. Besides the efficiency of 93-97[%]is obtained over the wide output voltage regulation ranges and load variations.