• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.172-174
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• 2007

The AC-DC Adapter has been widely used in Mobile Phones, Note Book PC, LCD monitors, and portable electronic products. Recently, high-power-density Adapter was developed. This adapter increases power factor using a bridge diode rectifier and PFC, however, there are weak points that improving efficiency is limited. In the bridgeless rectifier circuit proposed in this paper, there is no PFC, however, the power factor and efficiency are improved by BCM and ZCS operations.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.129-130
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• 2017

본 논문에서는 자기유도방식 무선충전 시스템의 송 수신 패드 위치 변화에 따른 공진주파수 변동을 보상하기 위한 bridgeless 정류기 동작에 대해 분석한다. Bridgeless 정류기의 스위칭 시점 및 duty 변화에 따른 공진네트워크 입력임피던스의 위상 변화를 수식적으로 분석하고, 시뮬레이션을 통하여 분석 결과를 검증한다.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.42-44
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• 2018

본 논문에서는 Bridgeless 정류기가 적용된 무선전력전송(Inductive Power System, IPT) 시스템의 성능 향상을 위한 스위칭 주파수의 변조 기법에 대해 제안한다. Bridgeless 정류기의 기존 제어 방식과 제안하는 제어 방식의 동작을 비교하고 3.3kW급 무선전력전송 시스템에 대한 시뮬레이션을 통해 제안하는 제어 방식에 대한 동작을 검증한다. 제안하는 제어 방식의 성능을 검증하기 위해 기존 제어 방식과의 손실을 비교 분석한다.

• Journal of Power Electronics
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• v.15 no.2
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• pp.356-365
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• 2015

This paper presents a new single phase front-end ac-dc bridgeless power factor correction (PFC) rectifier topology. The proposed converter achieves a high efficiency over a wide range of input and output voltages, a high power factor, low line current harmonics and both step up and step down voltage conversions. This topology is based on a non-inverting buck-boost (Zeta) converter. In this approach, the input diode bridge is removed and a maximum of one diode conducts in a complete switching period. This reduces the conduction losses and the thermal stresses on the switches when compare to existing PFC topologies. Inherent power factor correction is achieved by operating the converter in the discontinuous conduction mode (DCM) which leads to a simplified control circuit. The characteristics of the proposed design, principles of operation, steady state operation analysis, and control structure are described in this paper. An experimental prototype has been built to demonstrate the feasibility of the new converter. Simulation and experimental results are provided to verify the improved power quality at the AC mains and the lower conduction losses of the converter.

• Journal of the Semiconductor & Display Technology
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• v.19 no.4
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• pp.22-27
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• 2020

In this paper, a generalized efficiency equation was proposed to estimate the internal loss of the SMPS (switched-mode power supply) with 3 variables. The first variable was an internal loss not related to the load current such as auxiliary power, the second was a loss proportional to the current such as diode loss, and the third was a loss proportional to square of the current such as conduction loss. Especially, theoretical internal losses of the totem pole bridgeless PFC which is widely used for high efficiency SMPS were expressed as output function to compare generalized efficiency equation. In addition, in order to reduce the conduction loss of the switch, when a multiple switch were paralleled, the correlation with the efficiency was analyzed and shown as a graph. In order to confirm the degree of the parallel switch structure on the efficiency improvement, a 2kW class totem pole bridgeless PFC was constructed and the effectiveness of the analysis was confirmed by comparing the generalized efficiency equation and theoretical loss analysis results with experimental data.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.3
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• pp.293-301
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• 2011

This paper proposes a bridgeless half-bridge AC-DC converter with high-efficiency. The proposed converter integrates the bridgeless power factor correction (PFC) circuit with the asymmetrical pulse-width modulated (APWM) half-bridge DC-DC converter. It provides the isolated DC output voltage from the AC line voltage without using any full-bridge diode rectifier. Conduction losses are lowered with a simple circuit structure. Switching losses are also reduced by achieving zero-voltage switching (ZVS) of the power switches. By using series-connected two transformers, the proposed converter provides a low-profile and high power density for AC-DC converters. The performance of the proposed converter is verified from a 250 W (48 V / 5.2 A) experimental prototype circuit at $90 \;V_{rms}$ line voltage.

• Journal of Power Electronics
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• v.13 no.1
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• pp.40-50
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• 2013

In this paper, a new zero-voltage-switching, high power-factor, bridgeless rectifier is introduced. In this topology, an auxiliary circuit provides soft switching for all of the power semiconductor devices. Thus the switching losses are reduced and the highest efficiency can be achieved. The proposed converter has been analyzed and a design procedure has been introduced. The control circuit for the converter has also been developed. Based on the given approach, a 250 W, 400 Vdc prototype converters has been designed at 100 kHz for universal input voltage (90-264 Vrms) applications. A maximum efficiency of 94.6% and a power factor correction over 0.99 has been achieved. The simulation and experimental results confirm the design procedure and highlight the advantages of the proposed topology.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.81-83
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• 2018

본 논문에서는 inductive power transfer (IPT) 시스템 2차측 semi-bridgeless 정류기에 pulse density modulation (PDM) 제어를 적용하기 위한 시스템 설계 방안을 제안한다. LCCL-S 토폴로지를 사용한 IPT 시스템에 PDM 제어를 적용하였을 때 나타나는 출력특성을 기존의 SS 토폴로지를 사용한 시스템의 출력특성과 비교 분석한다. 분석 결과를 바탕으로, 실제 전기자동차 배터리 충전사양을 고려하여 3.3 kW 급 IPT 시스템을 설계하고 설계 결과를 시뮬레이션을 통해 검증한다.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.77-79
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• 2018

본 논문에서는 inductive power transfer (IPT) 시스템 2차측 semi-bridgeless 정류기에 pulse density modulation (PDM) 제어를 적용하였을 때 1차측에 나타나는 영향을 최소화하기 위한 공진 네트워크 설계 방안을 제안한다. PDM 제어를 적용하였을 때 2차측 전류 리플이 증가하는 문제를 해결하기 위해 2차측 수신 인덕턴스를 증가시킴으로써 전류 리플을 저감하여 1차측 영향을 최소화한다. 이를 위해 적절한 설계 조건을 구하는 방안에 대하여 제시하고, 방안의 적용에 따른 1차측 영향을 시뮬레이션을 통해 분석한다.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.223-227
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• 2016

Power supplies make the load compatible with its power source. DC power supplies are extensively used with most electrical and electronic appliances such as computers, television, and audio sets. The presence of non-linear loads results in a low power factor and higher harmonics in the power system. Several techniques for power-factor correction and harmonic reduction have been reported in the literature. This paper proposes a bridgeless boost converter that improves the power factor and reduces the harmonic content in input line currents as compared to full-bridge rectifiers. This bridgeless boost converter eliminates the need of a line-voltage bridge rectifier in conventional boost converter and thereby reduces conduction losses. The effectiveness of the proposed scheme is verified by computer simulations by using the PSIM software.