• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.175-176
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• 2014

본 논문은 전기자동차에 사용되는 배터리 충전기로써 3kW급 고효율 저전압 직류변환장치(LDC : Low Voltage DC-DC Converter) 개발에 관하여 기술한다. 토폴로지(Topology)는 LDC에 적합한 강압형 컨버터로써 전류를 분산시켜 효율증대가 가능한 다중 위상 벅 컨버터(Multi-phase Buck Converter) 구조를 채택하였다. 제안된 방식은 결합 인덕터(Coupled Inductor)를 사용하여 부피를 저감시킬 수 있으며, 디지털 제어를 이용하여 상위 제어기와의 통신을 할 수 있는 장점이 있다. 본 논문에서는 제안된 방식의 타당성을 검증하기 위하여 이론적으로 분석하며, 3kW급 시제품을 제작하여 제안방식의 타당성을 검증하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권4호
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• pp.216-223
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• 2006

In this paper, a methodology for the efficiency improvement of the photovoltaic system without adding some elements or increasing the cost comparing with the conventional system is discussed. It is suggested the optimal photovoltaic module configuration through its performance analysis, and also the suitable maximum power point tracking (MPPT) voltage considered the system cost and the efficiency of the converter. The high efficiency photovoltaic system by using the parallel power transfer (PPT) based MPPT converter is proposed and analyzed theoretically comparing with the conventional Buck type MPPT converter. Finally, it is designed and implemented the proposed photovoltaic system for supplying DC 48V by using the PPT based MPPT converter. And the effect of the efficiency improvement and the usefulness of the proposed system is proved through some preliminary simulation and experiment results.

• 전기전자학회논문지
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• 제23권1호
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• pp.254-260
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• 2019

본 논문에서는 양방향 dc-to-dc 컨버터의 고장원인, 고장영향, 고장 결과를 파악하기 위한 failure mode and effect analysis(FMEA)와 양방향 컨버터의 위험도를 고려한 fault-tree analysis(FTA)를 통해 고장률을 예측한다. 전기차의 구동전압을 효율적으로 상승시키기 위해 인버터 앞단에 부착되는 양방향 컨버터는 배터리 전력을 dc-link 커패시터로 방전시키는 승압모드와 회생전력을 배터리로 충전시키는 강압모드를 가진다. 양방향 컨버터의 동작 특성을 고려한 FMEA 결과를 바탕으로 컨버터의 위험도를 고려한 고장나무를 설계한다. 전기차 MCU용에 맞는 설계 파라메타를 설정하고 출력전압 리플과 인덕터 전류 리플에 따른 커패시터와 인덕터의 부품 고장률을 분석한다. 또한 동작 온도에 따른 주요부품의 고장률을 MIL-HDBK-217F를 이용하여 구한다. 마지막으로 부품 고장률을 고장나무의 기본 사상의 고장률로 반영하여 컨버터 고장률과 평균고장시간을 예측한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.601-602
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• 2008

This paper presents pulse-frequency modulation(PFM) to improve the light-load efficiency. The proposed circuit is designed by using the device parameter of standard $0.13{\mu}m$ CMOS process. The performance of proposed circuit is evaluated by HSPICE simulation Measured efficiency in a light-load is measured 78-90 % for 0.1 to 100mA output current.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.222-226
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• 2001

This paper compares three kinds of soft-switching circuits from viewpoints of surge suppression, load characteristic, and power efficiency for a tapped-inductor buck converter with low voltage and high current. As a result, these soft-switching techniques have achieved much higher efficiency of $80\%$ when compared with a hard-switching buck converter for the output condition of 1V and 20A.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.952-953
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• 2015

In this paper, various MPPT control in the most simple and widely used method of IC using the method According to the type of DC-DC converter to analyze the efficiency buck-boost convertor, Cuk convertor using each efficiency was analyzed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.378-381
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• 2002

Instantaneous following PWM control technique is pulsed nonlinear dynamic control method. This new control technique using analog integrator is proposed to control the duty ratio D of DC-DC converter. In this control method, the duty ratio of a switch is exactly equal to or proportional to the control reference in the steady state or in a transient. Proposed control method compensates power source perturbation in one switching cycle, and the average value of the dynamic reference in one switching cycle. There is no steady state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with buck converter have demonstrated the robustness of the control method and verified theoretical prediction. The control method is very general and applicable to all type PWM.

• 한국항공우주학회지
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• 제42권11호
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• pp.981-987
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• 2014

DC/DC 컨버터는 임의의 직류전원을 부하가 요구하는 형태의 직류전원으로 변환시키는 효율이 높은 전력변환기이다. DC/DC 컨버터는 MOSFET(산화물-반도체 전계 효과 트랜지스터), PWM-IC(펄스폭 변조 집적회로) 제어기, 인덕터, 콘덴서 등으로 구성되어있다. MOSFET는 스위치 기능을 수행하는데 코발트 60 ($^{60}Co$) 저준위 감마발생기를 이용한 TID 실험에서 방사선의 영향으로 문턱전압과 항복전압의 변화와 SEGR 실험에 적용된 5종류의 중이온 입자는 MOSFET의 게이트(gate)에 영향을 주어 게이트가 파괴된다. MOSFET의 TID 실험은 40 Krad 까지 수행하였으며, SEGR 실험은 제어보드를 구현한 후 LET(MeV/mg/$cm^2$)별 cross section($cm^2$)을 연구하는데 있다.

• 전기전자학회논문지
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• 제19권1호
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• pp.110-117
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• 2015

In this paper, a novel trench power MOSFET using a Separate-W-gated technique MOSFET (SWFET) is proposed. Because the SWFET has a very low $Q_{GD}$ compared to other forms of technology, it can be applied to high-speed power systems. The results found that the SWFET-applied $Q_{GD}$ was decreased by 40% when compared to simply using the more conventional trench gate MOSFET. $C_{ISS}$ (input capacitance : $C_{GS}+C_{GD}$), $C_{OSS}$ (output capacitance : $C_{GD}+C_{DS}$) and $C_{RSS}$ (reverse recovery capacitance : $C_{GD}$) were improved by 24%, 40%, and 50%, respectively. The switching characteristics of the inverter circuit shows a 24.9% enhancement of reverse recovery time, and the power efficiency of the DC-DC buck converter increased by 14.2%. In addition, the proposed SWFET does not require additional process steps and There was no degradation in the electrical performance of the current-voltage and on-resistance.

• 조명전기설비학회논문지
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• 제26권9호
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• pp.47-56
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• 2012

This research is to develop satiable battery charger with a variety of capacity and voltage specifications of battery. For this, voltage or current were controlled through buck converter which is DC voltage that already received three-phase at primary side and passed bridge rectifier diode. And, it was comprised of full-bridge converter and HFTR for insulation and a square wave AC. The transformer primary side was comprised in series to divide certain charging current and the secondly side was comprised of 6 fixed transformers so that they can generate certain amount of power and various output voltage through relay parallel compound 6 DC Link outputs. To confirm such structure's verification and validity, simulation with PSIM was conducted, and validity of proposed variable charger system was verified through 3kW stack production.