• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1158-1160
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• 1992

A new dc/ac soft switched PWM convert having a dc-link commutation circuit is proposed. The commutation circuit implemented by utilizing a series resonant circuit while preparing for zero voltage switching of primary inverter. The converter provides both variable pulse width and position which is fundamentally different than converters. In this paper, the operating principles, design and control considerations analysis of a such a soft switched converter is analyzed.

• 조명전기설비학회논문지
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• 제14권2호
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• pp.52-58
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• 2000

본 논문애서는 2단 스위치 구조를 가져는 역률 보상 회로를 적용하여 도통 손실을 저감할 수 있는 새로운 결합형 1단방식 AC/DC half-bridge 컨버터에 대한 토폴라지를 제안하고, 이에 관한 전류 불연속 모드 제어와 소프트 스위칭 특성에 대하여 연구하였다. 도통손실의 저감은 기존의 역률 보상 회로 대신 새로운 형태의 이단 스위치 구조를 가지는 역률 보상 회로를 적용함으로써 이루어친다. 제안된 토폴라지의 타당성 검증을 위해서 입력전압 100[V], 출력전압 50[V]의 500[W]급 컨버터에 대한 시뮬레이션 결과를 제시하고 분석하였다.

• 전력전자학회논문지
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• 제26권2호
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• pp.141-149
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• 2021

In the field of electric vehicles and AGVs, wireless power transfer (WPT) charging systems have been developed recently because of its convenience, reliability, and positive environmental impact due to cable and cord elimination. In this study, we propose a WPT charging system using a single stage AC-DC converter that can be reduced in size and weight and thus can ensure convenience. The proposed single-stage AC-DC converter can control a wide output voltage (36-54 VDC) within coupling ranges by using the variable link voltage applied to the WPT resonant circuit through phase-shifted modulation at a fixed switching frequency. Moreover, the input power factor and total harmonic distortion can be improved by using the proposed converter. A 1 kW prototype that can operate with an air gap range of 40-50 mm is fabricated and validated through experimental results and analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1023-1025
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• 2001

This paper proposes a bi-directional current switch with snubber regeneration using Power MOSFETs and this paper proposes to use a loss-less snubber with switching device to perform soft-switching. It results in not only decreasing switching loss in the device drastically, but also improving input ac current waveform distortion. The computer simulation results show that the input current waveform and show the requirements necessary for the elimination of the 3rd harmonic component. We also show the procedure to design the parameters of the converter.

• Journal of Power Electronics
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• 제10권3호
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• pp.293-299
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• 2010

In this paper, a single-phase PFC (Power Factor Correction) dual boost converter based on input voltage estimation is studied for DC inverter air conditioner. It is focused on improving input power factor and power quality to satisfy the recent harmonic current regulation standards. Furthermore the input voltage estimation is introduced for price competitive products. A low cost and reasonable control system is implemented using a specified high-speed 32-bit microprocessor. Their effectiveness are verified through theoretical analysis and experiments.

• Journal of Power Electronics
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• 제1권2호
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• pp.107-116
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• 2001

Two AC-DC PWM full-bridge converters that can input current to improve input power factor while performing dc-dc conversion are investigated in this paper. Both converters are simple in that they are similar to the standard PWM full-bridge converter with a diode rectifier/LC low-pass filter input, and both can operate with a simple method of PWM control. In the paper, the operation of the converters is explained and their steady-state characteristics are discussed. The feasibility of the converters and their ability to meet EN61000-3-2 Class D Standards for electrical equipment are shown with results obtained from experimental prototypes. The performance of both converters in terms of dc bus voltage level, input power factor and efficiency is compared and discussed.

• Journal of Power Electronics
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• 제11권2호
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• pp.188-193
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• 2011

A highly efficient AC-DC converter for small wind power generation systems using a brushless DC generator (BLDCG) is presented in this paper. The market standard AC-DC converter for a BLDCG consists of a three-phase diode rectifier and a boost DC-DC converter, which has an IGBT and a fast recovery diode (FRD). This kind of two-stage solution basically suffers from a large amount of conduction loss and the efficiency greatly decreases under a light load, or at a low current, because of the switching devices with a P-N junction. In order to overcome this low efficiency, especially at a low current, a three-phase bridgcless converter consisting of three upper side FRDs and three lower side Super Junction FETs is presented. In the overall operating speed region, including the cut-in speed, the efficiency of the proposed converter is improved by up to 99%. Such a remarkable result is validated and compared with conventional solutions by calculating the power loss based on I-V curves and the switching loss data of the adopted commercial switches and the current waveforms obtained through PSIM simulations.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.435-437
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• 2007

Authors propose a PFC(power factor correction) Buck-Boost AC-DC converter by soft switching method. The proposed converter for a discontinuous conduction mode eliminates the complicated control requirement and reduces the size of components. The input current waveform in the converter is got to be a sinusoidal form of discontinuous pulse in proportion to magnitude of ac input voltage under the constant duty cycle switching.Therefore,the input power factor is nearly unity and the control algorithm is simple. To achieve high efficiency system, the proposed converter is constructed by using a partial resonant technique. The control switches using in the converter are operated with soft switching for a partial resonant. The control switches are operated without increasing their voltage and current stresses by the soft switching method. The result is that the switching loss is very low and the efficiency of converter is high.

• 전력전자학회논문지
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• 제12권6호
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• pp.465-471
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• 2007

본 논문에서는 새로운 소프트 스위칭형 PFC 벅-부스트 AC-DC 컨버터에 대해 연구된다. 제안된 컨버터에 사용된 제어스위치의 턴-온과 턴-오프는 부분공진 동작에 의해 소프트 스위칭으로 되어 스위칭 손실을 줄이고, 입력전류는 듀티율 일정제어에 의한 교류 입력전압의 크기에 비례된 불연속적 유사 펄스열의 정현파 형태를 가진다. 그 결과 컨버터는 효율이 증대되고 입력역률이 증대되는 효과를 가진다. 또한 제안된 컨버터의 출력전압은 제어스위치의 PWM 제어에 의해 조정되고 벅-부스트용 인덕터에 흐르는 전류는 불연속모드로 제어되어 제어회로와 제어기법이 간단한 장점이 주어진다. 제안된 PFC 벅-부스트 컨버터는 기존의 PFC 벅-부스트 컨버터와 비교되어 해석되고 컴퓨터 시뮬레이션과 실험을 통해 그 해석적 타당성이 입증된다.

• 전력전자학회논문지
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• 제19권5호
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• pp.391-398
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• 2014

This paper presents a resonant step-down DC/DC converter to reduce the voltage stresses of a 3-phase inverter module under the three-phase AC utility line condition. Under this condition, a conventional 3-phase inverter module suffers from high voltage stresses as a result of the high rectified DC link voltage; hence, a high-cost high-voltage-rating inverter module must be used. However, using the proposed converter, a low-cost low-voltage-rating inverter module may be adopted to drive the motor even under the 3-phase AC line condition. The proposed converter, which can be realized with small size inductor and low-voltage-rating semiconductor devices, operates at a high-efficiency mode because of the zero-current switching operations of all the semiconductor devices. The operational principles are explained and a design example is provided in the study. Experimental results demonstrate the validity of the proposed converter.