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수동 역률 보상회로를 이용한 LED 센서등 회로의 개발
유진완(Park, Chong-Yeun),이학범(Yoo, Jin-Wan),박종연(Lee, Hak-Beom) 강원대학교 산업기술연구소 2012 産業技術硏究 Vol.32 No.1
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.
LED 조도제어 시 특성변화를 최소화하기 위한 PWM 주파수 선택방법
유진완(Jin-Wan Yoo),이무현(Mu-Hyun Lee),박종연(Chong-Yeun Park) 전력전자학회 2010 전력전자학술대회 논문집 Vol.2010 No.7
LED의 조도제어 방식은 타 방식에 비해 비교적 광색의 변화가 작고, 선형적인 조도제어가 가능한 PWM 방식을 사용한다. 본 논문은 LED를 PWM 방식으로 조도제어 했을 때, PWM 주파수에 의해 변화 하는 LED의 특성변화를 최소화하도록 주파수를 선택하는 방법을 제안하였으며, 이를 실험적으로 검증하였다.
전력선 통신을 이용한 LED 가로등의 원격조도제어 시스템 개발
김기남,유진완,박종연 江原大學校 産業技術硏究所 2010 産業技術硏究 Vol.30 No.B
In this paper, We proposed remote dimming control system for Light Emitting Diode(LED) street light using Power Line Communication(PLC). LED will be used widly by indoor or outdoor lighting because of semi-permanent life and environment restriction. For energy saving of street light, the dimming control system is very necessary and the PLC is a very efficient technique. Thus, in this paper we proposed the remote dimming control system for LED street light using PLC. A performance of the proposed system was validated by experimental results.
LED 기생 커패시턴스를 고려한 접합온도 측정 시스템의 개선
박종연,유진완 江原大學校 産業技術硏究所 2009 産業技術硏究 Vol.29 No.B
Recently, we have used LEDs to illumination because it has a high luminous efficiency and prolong lifespan. However the light power and lifetime is reduced by junction temperature increment of LED. So it is important to measure the junction temperature accurately. In case of using a electrical method measuring junction temperature of LED. Temperature measurement errors are spontaneously generated because of a parasitic capacitances in LED. In this paper, we proposed a method that reducing LED's parasitic capacitance effects for electrical measurement. It was demonstrated by the experimental result that is more correct than established method.
Design and Implementation of a Current-balancing Circuit for LED Security Lights
정광현,유진완,박종연 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.6
This paper presents a current-balancing circuit for security lights that uses parallel-connected LEDs. The parallel connection of LEDs causes current differences between the LED strings because of characteristic deviations. These differences can reduce the lifespan of a particular point of LEDs by thermal spotting. They can also cause non-uniform luminance of the lighting device. Among the different methods for solving these problems, the method using current-balancing transformers makes it easy to compensate for current differences and it has a simple circuitry. However, while the balancing transformer has been applied to AC light sources, LEDs operate on a DC source, so the driving circuitry and the design method have to be changed and their performances must be verified. Thus in this paper, a design method of the balancing transformer network and the driving circuitry for LEDs is proposed. The proposed design method could have a smaller size than the conventional design method. The proposed circuitry is applied to three types of 100-watt LED security lights, which use different LEDs. Experimental results are presented to verify the performance of the designed driving circuits.