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압전 트랜스포머를 이용한 PDA용 CCFL구동회로의 모델링과 동작특성
황락훈(L.H.Hwang),장은성(E.S.Jang),남우영(W.Y.Nam),류주현(J.H Yoo),오동언(D.O.Oh),조문택(M.T.Cho),안익수(I.S.Ahn),주해종(H.J.Joo) 전력전자학회 2003 전력전자학술대회 논문집 Vol.2003 No.7(1)
In This paper, to apply piezoelectric transformer for PDA backlight inverter, piezoelectric transformer using the composition which Nb₂O_5 added into PNW-PMN-PZT ceramics was fabricated as Rosen-type one with the size of 1165mm³. And their electrical characteristics were investigated with the variations of load resistance and driving frequency And then, the driving circuit for PDA CCFL(O.6W) which composed of the two MOSFETs connecting in series was manufactured using piezoelectric transformer, VCO and one-chip microprocessor. After driving for 25 min using the proposed circuit for PDA CCFL(O.6W), driving frequency of 214.4kHz, input voltage of 31.78 V and input current of 21.1mA were shown. And then, output voltage of 293.2 V and output current of 22mA were shown At the same time, efficiency of 96.2% and temperature rise of 3.6℃ were appeared at the piezoelectric transformer
벡터제어 시스템에 의한 유도 전동기의 속응제어와 토오크 특성에 관한 연구
황락훈(L.H. Hwang),장은성(E.S. Jang),남우영(W.Y. Nam),조상로(I.K. Ahn),신양호(M.T. Cho),조문택(H.J. Joo),이춘상(C.S. Lee),나승권(S.K. Na) 전력전자학회 2003 전력전자학술대회 논문집 Vol.2003 No.7(2)
In this paper, the speed control system of induction motor was proposed using vector control algorithm and space voltage vector PWM method to improve the dynamic performance of induction motor.<br/> The control system is composed of the PI controller for speed control and the current controller using space voltage vector PWM technique The high-speed calculation and processing for vector control is carried out by TMS320C3I digital signal processor and IGBT module The proposed scheme is verified through digital simulations and experiments for 3.7[kw] induction motor and shows good dynamic performance.<br/>
압전변압기와 CCFL 모델링에 의한 전자식 안정기 해석
황락춘(L.H. Hwang),장은성(E.S. Jang),신양호(Y.H. Shin),조상로(S.R. Cho),조문택(M.T. Cho),안익수(I.S. Ahn) 전력전자학회 2002 전력전자학술대회 논문집 Vol.- No.-
A CCFL model for high frequency dimming electronic ballast simulation is presented in this paper. The model can be utilized for an electronic ballast simulation with continuous dimming and transient mode simulation such as step dimming<br/> The piezoelectric transformer is evaluated using an AC analysis. The electronic ballast composed of piezoelectric transformers and ZVS Inverter was implemented. It enables a fluorescent lamp to be turned on stably.,<br/> simulation of a high frequency electronic ballast which operates a fluorescent lamp at high frequency is proposed simulation is carried out using PSPICE program to illustrate the performance of the circuit
황락훈(L.H. Hwang),장은성(E.S. Jang),남우영(W.Y. Nam),안익수(I.K. Ahn),조문택(M.T. Cho),주해종(H.J. Joo),이춘상(C.S. Lee),나승권(S.K. Na) 전력전자학회 2003 전력전자학술대회 논문집 Vol.2003 No.7(2)
This paper presents a detailed study of the extended Kalman filter for estimating the rotor speed of an 1M drive The general structure of the Kalman filter IS reviewed and the various system vectors and matrices are defined By including the rotor speed as a state variable, the EKF equations are established from a discrete two axis model of the three-phase induction motor using the software MA TLAB/Simulink, simulation of the EKF speed estimation algorithm is earned out for an induction motor drive with direct self control The investigations show that the EKF is capable of tracking the actual rotor speed provided that the elements of the covariance matrices are properly selected.<br/>
소규모 계통연계형 태양광 시스템의 최적제어에 대한 연구
황락훈(L.H.Hwang),장은성(E.S.Jang),남우영(W.Y.Nam) 전력전자학회 2003 전력전자학술대회 논문집 Vol.2003 No.11
The solar cells should be operated at the maximum power point because its output characteristics are greatly fluctuated on the variation of insolation, temperature and load.<br/> The output power of solar cell is DC, therefore it is necessary to install an inverter among electric power converts. The inverter have to supply a sinusoidal current and voltage to the load and the interactive utility line.<br/> In the paper, the proposes a photovoltaic system designed with a step up chopper and single phase PWM voltage source inverter. Synchronous signal and control signal was processed by microprocessor for stable modulation. The step up chopper operates in continuous mode by adjusting the duty ratio so that the photovoltaic system tracks the maximum power point of solar cell without any influence on the variation of insolation and temperature because solar cell has typical dropping character The single phase PWM voltage source inverter consists of complex type of electric power converter to compensate for the defect, that is, solar cell cannot be developed continuously by connecting with the source of electric power, from 10 to 20%. The single phase PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. The inverter supplies an ac power with high factor and low level of harmonics to the load and the utility power system
Onechip Microcontroller에 의한 압전 변압기를 이용한 T5 28W급 형광등 전자식안정기에 관한 연구
황락훈(L.H. Hwang),신양호(Y.H. Shin),조상로(S.R. Cho),장은성(E.S. Jang),조문택(M.T. Cho),안익수(I.S. Ahn),김주래(J.R. Kim) 전력전자학회 2002 전력전자학술대회 논문집 Vol.- No.-
In this paper, In order to solve the problem is proposed using a new type of electronic ballast that the traditional magnetic ballasts operated at 50-60Hz have been suffered from noticeable flicker, high loss, large crest factor and heavy weight which is composed of rectifier, active power corrector, series resonant half bridge Inverter, micro-controller and piezoelectric transformer for driving for driving T5 fluorescent lamp were manufactured The proposed electronic ballast operated at high frequency (about 75kHz) shows a input power factor of more than 0.995, total harmonic distortion of less than 12% and lamp current crest factor of less than 1 5, respectively. Output power and efficiency showed 28w and 85%, respectively. Accordingly, It is considered that the ballast using piezoelectric transformer can replace the typical electronic ballast
김종춘(J.C.Kim),정일록(I.R.Jung),황순홍(S.H.Hwang),장은성(E.S.Jang) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.11_1
Exhaust emission characteristics was investigated on gasoline vehicle which exceed by exhaust emission guarantee period(5 year:80,000 km). Before exhaust emission control equipped parts of vehicle which exceed by exhaust emission guarantee period(5 year:80,000 km). each pollutants emission was HC 0.41g/km, CO 4.17g/km, NOx 0.62g/km. These HC and CO emission was double of exhaust emission standard within exhaust emission guarantee period. After repair of these gross pollutant emission vehicle, each pollutant emission was HC 0.16g/km, CO 1.06g/km, NOx 0.19g/km. These emission characteristics was similar to new vehicle's. Although exhaust emission of vehicle was not related uesd year, Exhaust emission was highly increased on 5 year over used vehicle.<br/>