• Journal of Power System Engineering
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• v.9 no.4
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• pp.168-174
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• 2005

A coreless electronic transformer is proposed. Conventional iron cored transformer is heavy and bulky and it has substantial amount of no load loss. On the other hand, electronic transformer can be made of negligible no load loss and is small size and lightweight. It consists of rectifier and PWM inverter. Electronic transformer is easily modeled to conventional Buck converter; therefore, output voltage is controlled by duty ratio. It is thought to be suitable for applications where the operation duty is low. In this paper, a novel coreless transformer is proposed, then it's detailed analysis, simulative and experimental results are presented

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.939-940
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• 2006

An integrated inductor using the low-temperature co-fired ceramics(LTCC ) technology for low-power electronics was fabricated. In the inductor NiZn ferrite sheet(${\mu}_r=230$), was embedded to increase inductance. The inductor has Ag spiral coil with 14 turns($7turns{\times}2layers$), a dimension of 0.6mm in width, 10um in thickness, and 0.15mm pitch. To evaluate the inductance, including the parasitic resistance, the fabricated inductor was calculated and measured. It was confirmed that calculated values were very close to the measured values. Finally as an application of the LTCC integrated inductor to low power electronic circuits, a LTCC buck DC/DC converter with 1W output power and up to 0.5MHz switching frequency using the inductor fabricated was develop.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.328-329
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• 2018

본 논문에서는 전기자동차용 단상 온-보드 충전기를 위한 Cycloconverter-type High Frequency Link 회로구조와 능동 전력 디커플링 회로를 이용한 전기자동차용 고전력밀도 양방향 온-보드 충전기를 제안한다. 제안된 시스템은 전력변환부 단계를 줄이기 위한 AC-AC 변환회로와 DC링크 캐패시터를 최대한 줄이기 위해서 벅-타입 능동 전력 필터를 사용한다. 이를 통해 전력변환시스템 전체의 부피를 줄일 수 있으며, 전해 커패시터를 필름 커패시터로 대체하여 수명 문제를 해결할 수 있다. 제안된 시스템의 성능은 MATLAB/Simulink 시뮬레이션을 통해 검증하였다.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.334-335
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• 2018

본 논문에서는 스위칭 소자의 저항을 고려한 벅 컨버터의 소신호 모델링을 통해 회로를 등가화하고, 등가 모델의 동특성을 분석하였다. 또한 분석한 결과를 토대로 3P2Z(3Pole 2Zero) 제어기를 기반으로 한 전압 보상 제어기를 구현하였다. MATLAB을 이용하여 등가 모델을 바탕으로 설계한 제어기의 안정도를 판별 및 분석하였고, 최종적으로 PSIM을 사용한 시뮬레이션을 통해 분석한 결과가 타당함을 검증하였다.

• Journal of Industrial Technology
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• v.32 no.A
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• pp.109-114
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• 2012

In this paper, We studied LED(Light Emitted Diode) sensor lights system using PIR(Pyroelectric Infrared Ray) sensor, CdS and MCU(Micro Controller Unit). And applied the valley fill circuit to improve the power factor. We designed the amplifier for each sensor and the LED driver for constant current which is the buck converter. Also, we proposed the algorithm of LED control by each sensors using MCU. Experimental results showed that power factor is 92% with valley fill circuit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.14-21
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• 2012

This paper study a method of modeling and simulation of LED driver circuit for a design optimization. Simplified LED modeling is introduced and a driver IC, HV9910, is modeled by implementing the major function blocks. Circuit of buck type converter is constructed for simulation. Simulation includes not only the internal function of IC but also the various performance results such as LED array current control and dimming. Experiment results are also shown to prove the verification of its usage. This results show that the simulation approach is valid for a circuit optimization and a reduction of development time.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.113-115
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• 2008

This paper shows the method of modeling and simulation of LED driver circuit. Simplified LED modeling is introduced and a driver IC, HV9910, is modeled by implementing the major function blocks. Circuit of buck type converter is constructed for simulation. Simulation includes the internal function of IC and various performances such as LED array current control and dimming. This results show that simulation approach is valid for circuit optimization and reduction of development time.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.288-292
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• 2010

Recently, in energy storage system, the EDLC is paid attention as a new environmentally friendly energy storage element. This capacitor has higher energy density than the electrolytic capacitor. Also, this capacitor has a lot of advantage such as no maintenance, longer life cycle and faster charge-discharge time than the battery system. But the EDLC must have a each charge-discharge controller to effectively control, an energy design method circuit to use effectively energy, and several compensation techniques to control a optimal operating. In this respect, this study suggests major parameters to effectively represent the characteristics of EDLC, the measurement methods of those parameters have been investigated with experiments, and the interpretation about the buck/boost DC/DC converter for the operation of EDLC.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.677-681
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• 2005

This Paper presents a 6 pulse shift operation control mode of current-source-inverter to make improvement of efficiency and to reduce the frequency of inverter switching for photovoltaic generation system using PWM current-source-inverter. This system is connected solar cell energy directly without using a storage cell. The proposed circuit can maintain maximum voltage of photovoltaic generation of take advantage of six Buck-Boost converter and a full-bridge inverter determines the polarity of AC output. That is controlled by using digital signal processor TMS320F2812 for operation about a 6 pulse shift operation control of current-source-inverter, and it is verified through the experimental results.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.258-259
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• 2013

본 논문에서는 저가형의 고효율 이단형 탭인덕터 벅-부스트 컨버터를 적용한 마이크로 인버터를 제안한다. 제안하는 인버터는 정상상태 연속모드(CCM)에서 단상전력계통에 고역률의 정현파전류를 공급할 수 있는 새로운 구조이다. 강압시에는 벅 모드로 동작하며, 승압시에는 탭인덕터 부스트 모드로 동작한다. 정류형태의 전류를 인버터에 공급하며, 낮은 주파수를 사용하는 전파정류 인버터가 고역률의 교류 파형으로 변환한다. 벅-부스트에 탭인덕터를 적용함으로써 권선비에 따른 시비율을 조절할 수 있어 극단적인 승압시에도 벅-부스트의 도통을 적절히 유지할 수 있다. 제안하는 인버터는 정상상태 연속모드(CCM), 200W급 하드웨어 프로토타입을 통해 동작특성 및 효율 분석을 하였다.