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LCsCp 공진 타입의 하프 브리지 인버터 구조를 가지는 전자식 안정기 보호회로 설계
최현희(Hyeon-Hui Choe),박종연(Chong-Yun Park) 대한전기학회 2009 전기학회논문지 Vol.58 No.8
The electric ballast for ceramic metal halide lamp needs a protection circuit to prevent from over voltage and over current in the case that the lamp or the electric ballast are in faults. In this paper, cost-effective and high performance protection circuit is proposed for the electric ballast. The proposed protection circuit is adapted to the electric ballast with resonance type half bridge inverter. The experimental results demonstrate that the proposed circuit can protect effectively under open and short fault conditions.
최현희(Hyeon-Hui Choe),최왕섭(Wang-Seop Choi),박종연(Chong-Yun Park) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
Dual Buck Inverter구조를 가지는 70W CDM 램프용 전자식 안정기의 제어기를 설계하였다. 전자식 안정기는 EMI filter, Active PFC, Dual Buck Inverter, Igniter, SMPS로 구성 된다. 제어기는 크게 2개로 구분 할 수 있다. MC33262를 이용하여 Inverter의 전압, 전류를 센싱 받아 70㎑의 Zero Voltage Switching을 위한 제어기와 시간의 경과에 따라 PFC의 출력 전압 제어, Ignition Pulse 제어 및 무부하 보호를 위한 제어기로 구성되어 있다. 본 논문은 ATmega8을 이용하여 제어기를 설계하였고 실험으로 시간의 경광 따른 안정기의 제어가 안정적인 동작을 하고 있음을 증명하였다.
최현희(Choe Hyeon Hui),장명재(Jang Myeong Jae),남정혜(Nam Jeong Hye),송종국(Song Jong Gug) 한국사회체육학회 2003 한국사회체육학회지 Vol.20 No.2
The present study investigated the effect of percent body fat(%fat) on cardiorespiratory function in female university students. Thirty female university students with mean age of 20.6±0.57 years were participated in this study. The subject were divided into three groups according to the level of percent body fat including control group(20∼24.9%fat), overweight group(25∼29.9%fat), and obesity group(30∼ 35%fat). Anthropometric measurements included height and weight. Body mass index was calculated. Percent body fat and fat-free mass were measured by bioelectrical impedance analyzer(Inbody 3.0, Korea). Maximal exercise treadmill test was done by modified Bruce protocol. The test was performed at the speed of 1.7mph on the degree of 0% in the beginning, increasing the speed of 0.8mph and 5% of degree every three minutes. The result of the study showed that significant difference(p<0.01, F=6.227) can be observed between the groups in rest oxygen consumption. Obese group(0.195L·min-1) had highest value of oxygen consumption compared to control group(0.18L·min-1). There was significant difference(p<0.01) between groups for oxygen consumption per lean body mass and oxygen pulse during rest. Control group(4.818㎖·FFM-1·min-1, 2.426㎖·beats-1) showed significant lower value of oxygen consumption per lean body mass and oxygen pulse than the other two groups. On the other hand, no difference were found for carbon dioxide production, respiratory quotient, heart rate and minute ventilation between groups. As a result of this study, it can be suggested that cardiorespiratory function may be influenced by level of percent fat.
LCpCs 공진 탱크를 이용한 방전등용 전자식 안정기의 감도특성 해석
박종연(Park Chong yeon),최현희(Choe Hyeon hui) 강원대학교 산업기술연구소 2008 産業技術硏究 Vol.28 No.1
This paper studied the sensitivity characteries of the electronic ballast for the discharge lamps, which implies variation ratio of the output power by the passive element variation. We have derived the equation to represent the lamp power, and obtained the sensitivity characteristic equations. The simulation result shows that the proposed equations are correct and very useful to design the electronic ballast with the LCpCs-type resonant tank.
Ceramic 메탈 헬라이드 램프용 Dimming 전자식 안정기 개발
임기승(Ki-Seung Lim),최현희(Hyeon-Hui Choe),신동석(Dong-Seok Sin),박종연(Chong-Yun Park) 대한전기학회 2009 전기학회논문지 Vol.58 No.10
Metal halide (MH) lamps have been largely used due to high luminous efficiency, good color rendering, and long life. Since the metal halide lamps have problems of high ignition voltage and acoustic resonance. Thus, the design of ballast is very difficult for engineers. This paper proposes prototype of electric ballast in order to solve above two problems. The proposed electric ballast is consisted of EMI filter, full wave rectifier circuit, active PFC, DBI(Dual Buck Inverter), dimming circuit and ignitor circuit. The DBI supplies both rectangular voltage and current to the lamp. As the result of the experiment, the acoustic resonance was eliminated and the ignitor circuit was designed to generate high ignition voltage than 5kV. It makes the dimming circuit possible to control the lamp power in range between 230W and 350W
박종연(Chong-Yun Park),임기승(Ki-Seung Lim),신동석(Dong-Seok Sin),최현희(Hyeon-Hui Choe) 대한전기학회 2009 전기학회논문지 Vol.58 No.4
This paper proposes a high efficient Dual Buck Inverter design with a zero voltage switching (ZVS) control technique. The ZVS control is realized by adding a feedback loop circuit which is implemented by simple RS latch and TTL gate. The used load was 200W-Ceramic Metal Halide Lamp. The experimental results show that the proposed Inverter system could avoid the acoustic resonance and achieve high efficiency by Zero Voltage Switching.
남녀 체조선수들의 신체크기, 골격성숙, 혈중철분지표 비교
송종국(Song Jong Gug),강형숙(Kang Hyeong Sug),최현희(Choe Hyeon Hui) 한국사회체육학회 2003 한국사회체육학회지 Vol.20 No.2
The aims of the study were 1) to investigate the present status of body size, skeletal maturation and hematological parameters and 2) to assess relationship of these variables in male and female gymnasts. One hundred six gymnasts including 54 male and 52 female gymnasts were participated in the study. Mean age of the male and female gymnasts were 14.7±3.37 years and 14.3±3.06 years, respectively. Anthropometric characteristics included body weight, height, sitting height, 2 bone widths, 8 circumferences, and 5 skinfold thicknesses. Skeletal maturation was assessed by the Tanner-Whitehouse II method. Skeletal age was determined by RUS scores (radius, ulna, and short bones). Hemoglobin(Hb), hematocrit(Hct), red blood cell(RBC), white blood cell(WBC), ferritin, mean corpuscular volume(MCV), mean corpuscular hemoglobin concentration(MCHC), and mean corpuscular hemoglobin(MCH) were analyzed by automated instrumentation(ADVIA 120, Bayer, USA). Serum iron and total iron binding capacity(TIBC) were determined by auto-analyzer(HITACHI 7150, Tokyo, Japan) and transferrin saturation(TS) was calculated by dividing serum iron concentration by TIBC. All statistical analysis were carried out by the SAS computer programs. The results indicated that significant difference could be observed for anthropometric measurements including body weight(43.2kg vs 38.7kg), upper arm(25.3cm vs 23.2cm), upper arm flexed(27.1cm vs 24.3cm), chest(83.9cm vs 76.0cm), and waist(63.3cm vs 60.0cm) circumferences, triceps(7.6mm vs 9.7mm), thigh(11.3mm vs 15.3mm), and calf(8.7mm vs 11.4mm) skinfolds, and femur diameter(8.4cm vs 7.7cm) between male and female gymnasts. Means of RUS score and bone age were 497.2, 12.8year for male and 654.3, 12.0year for female gymnasts. Analysis of covariance showed that there are significant difference for RBC(p<0.05, F=5.72), Hct(p<0.05, F=4.96), Ferritin(p<0.05, F=5.84), between male and female gymnasts. On the other hand, other hematological parameters including WBC, Hb, TF, serum iron, TIBC, MCV, and MCH were not significantly different between two groups of the subjects. Body weight and height are significantly related to RBC, Hct, MCV, MCH. Significant relationships were also found between bone age and RBC(r=0.23), MCV(r=0.33), and MCH(r=0.26). As a result of the study, it can be suggested that body size and skeletal maturation are related to hematological parameters in gymnasts.
조도 제어용 ASK 및 FSK 전력선 모뎀의 성능 평가
박종연,최현희 강원대학교 정보통신연구소 2008 정보통신논문지 Vol.12 No.-
In this paper, two type of power line modems are evaluated to realize the lamp control system using the power line communication. One is FSK modem using DS/SS and the other is the manchester coded ASK modem. Both modems apply (7,4) hamming code to correct errors. There are two kinds of used loads ; the electronic ballast and the magnetic ballast. The Electronic ballast is for a 250Watt HID lamp, a 50watt florescent lamp and a 50watt induction lamp. The Magnetic ballast is for a 250watt HID lamp. Bit errors are measured between the main modem and the ASK or the FSK sub-modems in loads at equal distances. As a result, it is estimated that the FSK modem is more appropriate than the ASK modem in terms of the lamp dimming system. And we also concluded that the (7,4) hamming code is not suitable for ASK application In the lamp control system.