• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.198-199
• /
• 2013

본 논문은 군용 UPS 시스템에서 Dual Active Bridge(DAB) 컨버터를 이용한 절연형 양방향 배터리 충전기를 제안한다. 일반적인 군용 UPS 시스템은 AC-DC 정류기, DC-AC 인버터, 양방향 DC-DC 컨버터, 배터리 충전기, 배터리로 구성되며, 여러 부하상태들에 대한 지속적인 전력공급을 위하여 안정적인 에너지 저장 시스템이 요구된다. 다양한 양방향 DC-DC 컨버터들 중, DAB 컨버터는 buck, boost 동작이 가능한 고효율 절연형 양방향 컨버터이다. 본 논문에서는 6kW(입력 380Vdc, 출력 32/21Vdc) DAB 컨버터에 대한 토폴로지 분석하고, 파라미터 및 제어 알고리즘 설계를 제안하고 시제품을 통해 이를 검증하였다.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.1336-1338
• /
• 2000

This paper proposed the single phase multi-level PWM AC/DC converter using binary combine which controls input current by combining buck converters to improve input current characteristic, and confirmed its validity throughout simulation and experiment. This method, which is multiplying and duplicating output of converter of equal capacity, has the advantage of being able to control unit power factor of input current and reducing of the problem caused by high frequency switching, and appling to high power converter because filter is not necessary etc.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.922-923
• /
• 2008

This paper is proposed to a novel DC-DC buck-boost converter added electric isolation by using a soft switching method. To be achieved of high efficiency system, the proposed converter is constructed by using a partial resonant circuit. The control switches using in the converter are operated with soft switching for a partial resonant method. The controlling switches are operated without increasing their voltage and current stresses by the soft switching technology. The result is that the switching loss is very low and the converter efficiency is high. And the proposed converter is added in a electric isolation. When the power conversion system is required to electric isolation, the proposed converter is adopted with system development of high efficiency. The soft switching operation and the system efficiency of the proposed converter is verified by digital simulation and experimental results.

• Proceedings of the KIEE Conference
• /
• 1989.11a
• /
• pp.235-239
• /
• 1989

This paper investigated the effect of right half plane zero on the transient response in the buck-boost DC-DC converter. And it is clarified that the damping ratio decreases gradually by increases of the feedback loop gain and the regulation system of the converter becomes unstable. From the result, we obtained the stability region about the duty ratio and the output current by evaluating the feedback loop gain.

• Proceedings of the KIEE Conference
• /
• 2009.04b
• /
• pp.115-117
• /
• 2009

본 논문은 단일 디지털 제어기를 이용하여 독립형 태양광 발진 시스템에 사용되는 태양전지에서 발생한 전력을 수집하고 필요에 따라 에너지 저장 장치에 전력을 저장하는 Boost 컨버터가 최대전력점에서 동작하도록 제어하면서, 이 전압을 부하에 필요한 전압 값으로 변환하는 Buck 컨버터를 동시에 제어하는 방법을 제안한다. 제안된 독립형 태양광 발전 시스템의 구성은 에너지를 발생하는 태양전지, 최대전력 점을 추종(MPPT)하도록 하는 Boost 컨버터, 부하에 적합한 준위의 전압을 공급하는 Buck 컨버터가 직렬로 연결되어 있다. 제안된 방법은 디지털 제어기의 제어변수 값들을 바꿈으로써 전체시스템의 출력특성을 쉽게 제어할 수 있어, 사용되는 태양전지 어레이의 종류와 환경조건 변화에 따라 쉽게 제어변수 값들을 조정할 수 있다. 또한 하나의 디지털 제어기로 최대전력점 제어부 및 Buck과 Boost 컨버터의 피드백 제어부를 구성하여 시스템의 구조가 간단해지기 때문에 소형 및 경량화를 이룰 수 있다.

• Proceedings of the KIEE Conference
• /
• 2004.10a
• /
• pp.131-133
• /
• 2004

본 연구는 출력단에 패캐시터를 갖고 있는 AC 전류원으로부터, 밧데리 충전을 위한 새로운 AC/DC 컨버터 회로를 제안한다. 영전압과 영전류 스위칭을 사용하여 컨버터의 소형화 및 고효율화를 추구하였고, 풀브리지 MOSFET 정류기와 Buck-boost 컨버터가 결합된 새로운 토폴로지의 회로를 구성하였다. 제안된 컨버터의 동작원리 및 동작모드를 해석하고, PSpicc 시뮬레이션을 통해 해석결과를 검증하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.9
• /
• pp.42-50
• /
• 2015

The Buck-Boost converter consisted of two switches is more expensive than the conventional Buck converter, because of the increase of the components. However, it can control the DC voltage depending on the requested load voltage without additional circuits, because it can control the voltage under the relatively wide range of the load. Additionally, it can control the output voltage constantly under the variation of the input voltage. In the paper two control loops consisted of current and voltage control are designed. When two controllers are operated at the same time the problem of the output voltage is occurred. Therefore, the solution of the output voltage problem is proposed. Finally, the validity of the proposed scheme is investigated with simulated and experimental results for a prototype system rated at 1kVA.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.1
• /
• pp.125-134
• /
• 2016

We propose an efficient high voltage level shifter for a high side Buck converter driving a light-emitting diode (LED) lamp. The proposed circuit is comprised of a low voltage pulse width modulation (PWM) signal driver, a coupling capacitor, a resistor, and a diode. The proposed method uses a property of a PWM signal. The property is that the signal repeatedly transits between a low and high level at a certain frequency. A low voltage PWM signal is boosted to a high voltage PWM signal through a coupling capacitor using the property of the PWM signal, and the boosted high voltage PWM signal drives a p-channel metal oxide semiconductor (PMOS) transistor on the high side Buck converter. Experimental results show that the proposed level shifter boosts a low voltage (0 to 20 V) PWM signal at 125 kHz to a high voltage (370 to 380 V) PWM signal with a duty ratio of up to 0.9941.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.25 no.6
• /
• pp.425-432
• /
• 2020

The phase-shifted, full-bridge (PSFB) DC-DC converter is widely used in electric vehicles (EVs) to charge a low-voltage (12 V) battery from a high-voltage battery. A Photovoltaic (PV) module-integrated PSFB converter is proposed for the EV power conversion system. The converter is useful because solar energy can be utilized to extend the driving range. The buck converter circuit is simply realized by adding one switch to the conventional PSFB converter's secondary side. For the inductor and diode, the existing components in the PSFB converter are shared. The proposed converter can charge a low-voltage battery from the PV module with maximum power point tracking. In addition, the two power sources can be used simultaneously, and efficiency is increased by reducing the circulating current, which is a problem for the conventional PSFB converter.

• Proceedings of the KIPE Conference
• /
• 2013.11a
• /
• pp.145-146
• /
• 2013

본 논문은 슈퍼커패시터용 양방향 DC-DC 컨버터의 고주파 변압기 권선비를 고려한 설계에 대해 다루었다. 양방향 DC-DC 컨버터는 슈퍼커패시터의 충전시 스위칭 손실을 줄이기 위해 듀티(Duty)를 제어하여 Buck 모드로 동작하고, 방전시 부하변동에 빠르게 대처하기 위해 Phase-shift 모드로 동작한다. 충전시와 방전시 각각의 동작에서 스위치손실과 변압기의 손실을 분석하여 손실을 최소로하는 변압기 권선비를 선정하고자 한다.