• 전기학회논문지
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• 제60권1호
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• pp.71-77
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• 2011

An analysis, which is focused on electrical losses of an electrical propulsion system with High voltage DC/DC Converter (HDC) for a hybrid and an electric vehicle, is presented. From the analysis, it can be known that the electrical losses are closely related to the dc link voltage of the HDC, and there is an optimal dc link voltage which minimizes the losses. In this paper, the method to decide the optimal dc link voltage is proposed and the comparison on the losses by the control methods of the dc link voltage, during a driving cycle, is performed and the result is also presented.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.216-225
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• 2006

This paper presents a new circuit topology of DC busline switch and snubbing capacitor-assisted full-bridge soft-switching PWM inverter type DC-DC power converter with a high frequency link for low voltage large current applications as DC feeding systems, telecommunication power plants, automotive DC bus converters, plasma generator, electro plating plants, fuel cell interfaced power conditioner and arc welding power supplies. The proposed power converter circuit is based upon a voltage source-fed H type full-bridge high frequency PWM inverter with a high frequency transformer link. The conventional type high frequency inverter circuit is modified by adding a single power semiconductor switching device in series with DC rail and snubbing lossless capacitor in parallel with the inverter bridge legs. All the active power switches in the full-bridge inverter arms and DC busline can achieve ZVS/ZVT turn-off and ZCS turn-on commutation operation. Therefore, the total switching losses at turn-off and turn-on switching transitions of these power semiconductor devices can be reduced even in the high switching frequency bands ranging from 20 kHz to 100 kHz. The switching frequency of this DC-DC power converter using IGBT power modules is selected to be 60 kHz. It is proved experimentally by the power loss analysis that the more the switching frequency increases, the more the proposed DC-DC converter can achieve high performance, lighter in weight, lower power losses and miniaturization in size as compared to the conventional hard switching one. The principle of operation, operation modes, practical and inherent effectiveness of this novel DC-DC power converter topology is proved for a low voltage and large current DC-DC power supplies of arc welder applications in industry.

• 조명전기설비학회논문지
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• 제21권6호
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• pp.55-64
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• 2007

본 논문은 부하직렬 고주파 공진 DC/DC 컨버터에 가변 가능한 공진커패시터를 병렬로 삽입한 LCC형 고주파 공진 DC/DC 컨버터의 특성과 설계 예를 나타내고 있으며, 또한 턴-오프시 스위칭 손실을 줄이기 위해 ZVS를 가지는 소프트 스위칭을 사용하였다. 제안 컨버터는 PFM(Pulse Frequency Modulation) 스위칭 패턴을 사용하여 동작되며, PFM 제어에 의해 제안 회로의 출력전압을 제어하였다. 병렬커패시터의 커패시턴스의 변화에 따라, DC/DC 컨버터의 분석은 일반적으로 무차원화 파라미터를 사용하여 나타내었고, 회로 동작 특성은 스위칭 주파수와 파라미터로 행하였다. 또한 본 논문은 특성평가에 의해 제안 DC/DC 컨버터의 동작 특성과 회로 설계 방법을 제시하였다. 더욱이 본 논문은 실험을 통해 이론 분석의 정당성을 입증하였다. 향후 제안한 DC/DC 컨버터는 반도체 및 FPD의 클린룸에 선형이동 시스템의 비접촉 전원장치에 적용 가능하다고 생각된다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.237-239
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• 2017

The isolated boost DC-DC converter based on three switches in fuel cell applications is presented in this paper. The major advantages of the proposed converter are as follows: continuous input current; decrease one active switch and no use snubber circuit. The operating principles and analysis of the proposed converter have been discussed. A 400 W prototype has been tested in the laboratory to verify the performance of the proposed converter and a PID controller was used to clarify the DC output voltage at 400 V. The simulation and experimental results are shown to validate the theoretical analysis.

• 전기전자학회논문지
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• 제25권4호
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• pp.741-749
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• 2021

본 논문에서 제안한 전류형 LLC AC to DC 고주파 공진 컨버터는 스위치 양단에 병렬로 공진 커패시터(C₁, C₂)를 연결함으로써 ZVS(Zero Voltage Switching)동작 뿐만 아니라 2차측 Diode의 ZCS(Zero Current Switching) 동작이 가능하므로 스위칭 소자의 턴-온 및 2차측 다이오드의 턴-오프 손실을 저감시킬 수 있다. 본 논문에서 제안한 LLC AC to DC 고주파 공진 컨버터의 회로 해석은 무차원화 제어 파라메타를 도입하여 범용성 있게 기술하였다. 또한 제안한 LLC AC to DC 고주파 공진 컨버터의 운전 특성은 무파원화 제어 주파수(μ), 무차원화 저항(λ) 등의 무차원화 제어 파라메타를 이용하여 특성 평가를 수행하였다. 특성 평가를 통한 특성값을 기초한 LLC AC to DC 고주파 공진 컨버터 설계 기법의 일예를 제시하였으며, 실험 및 PSIM 시뮬레이션을 통해 이론 해석의 정당성을 입증하였다.

• Journal of Power Electronics
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• 제16권6호
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• pp.2016-2023
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• 2016

This paper presents a simple input-constrained current controller for a DC/DC boost converter with stability analysis that considers the nonlinearity of the converter model. The proposed controller is designed to satisfy the inherent input constraints of the converter under a physically reasonable assumption, which is the first contribution of this paper. The second contribution is providing a rigorous proof of the proposed control law, which keeps the closed-loop system along with the internal dynamics stable. The performance of the proposed controller is demonstrated through an experiment employing a 20-kW DC/DC boost converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.277-280
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• 2006

Recently, the high frequency isolated boost DC/DC converter has been widely used for the PCS (Power Conditioning System) system because of its small size and low cost. However, the high frequency isolated boost DC/DC converters applied the conventional voltage-fed converter and current-fed converter have the problems such as the high conduction losses and the surge voltage due to the high circulating current and the leakage inductance, respectively. To overcome this problems, in this paper the secondary LLC resonant converter is proposed, and the experimental results of the secondary LLC series resonant converter for boost DC/DC converter are verified on the simulation based on the theoretical analysis and the 1kW experimental prototype.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.97-101
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• 2003

In this paper, we propose a new diagnosis method of DC/UC converter aging. The method is based on parasitic resister change with aging process. we apply to on-line diagnosis of DC/DC converter because of observing not a device but a system. We present the mathematical analysis and experimental study.

• 전력전자학회논문지
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• 제24권4호
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• pp.229-236
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• 2019

This study proposes a DC-DC converter topology of solid-state transformer for low-voltage DC distribution. The proposed topology consists of a voltage balancer and bipolar DC-DC converter. The voltage and current equations are obtained on the basis of switching states to design the controller. The open-loop gain of the controller is achieved using the derived voltage and current equations. The controller gain is selected through the frequency analysis of the loop gain. The inductance and capacitance are calculated considering the voltage and current ripples. The prototype is fabricated in accordance with the designed system parameters. The proposed topology and designed controller are verified through simulation and experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1425-1427
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• 2005

In this paper, with loosely coupled transformer series-parallel resonant type DC/DC converter is analyzed. To get more efficient operating mode of the series-parallel resonant type DC/DC converter, theoretical analysis using normalized parameters are accepted. The proposed converter must be operated in Pulse Frequency Modulation(PFM) switching pattern for the Zero Voltage Switching(ZVS) operation. According to PFM control method, the output voltage of the proposed circuit can be controlled.