• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.1121-1124
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• 2003

PZT(30/70) thick film was fabricated by using 1,3 propanediol-based sol-gel method. Prepared film of pyroelectric property was investigated by Dynamic method of modulation frequency dependence. Pyroelectric coefficient was obtained about 5.0$\times$10$^{-8}$ C/$\textrm{cm}^2$.K. The figure of merits for voltage responsivity and specific detectivity were 3.4$\times$10$^{-11}$ C.cm/J and 5.9$\times$10$^{-9}$ C.cm/J, respectively, because of relative high-dielectric constant and high-pyroelectric coefficient. Voltage responsivity was increased at low modulation frequency and it was decreased at high modulation frequency. Voltage responsivity was maximum 1.84 V/W at 10 Hz. As Johnson noise is dominant, Noise voltage was increased nearly proportional to f$^{-1}$ 2/. Noise equivalent power and specific detectivity were 2.83$\times$10$^{-7}$ W/Hz$^{1}$2/ and 3.13$\times$10$^{5}$ cm.Hz$^{1}$2//W the same frequency at 80 Hz, respectively.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 추계학술대회 논문집
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• pp.133-135
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• 2007

This research presented the new zero-current switching pulse width modulation SEPP(Single Ended Push-Pull)high frequency inverter for solving the problem of the zero-current SEPP high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the zero-current switching pulse width modulation SEPP high frequency inverter. The inverter circuit which is attempted by on-off operation of a switch has the reduction effect of the power loss due to a soft switching and a high frequency switching. And it confirmed that the power regulation is possible continuously from 0.25[kW] until 2.84[kW] in the case the duty rate(D) changes from 0.08 to 0.3 under zero-current switching operating by a dissymmetry pulse width modulating control and the power conversion efficiency comes true the efficiency of 95[%]. Due to the result above, the ZCS PWM SEPP high frequency inverter will be effective as sources of an induction heating apparatus.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
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• pp.119-124
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• 2007

This research presented the new zero-current switching pulse width modulation SEPP(Single Ended Push-Pull)high frequency inverter for solving the problem of the zero-current SEPP high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the zero-current switching pulse width modulation SEPP high frequency inverter. The inverter circuit which is attempted by on-off operation of a switch has the reduction effect of the power loss due to a soft switching and a high frequency switching. And it confirmed that the power regulation is possible continuously from 0.25[kW] until 2.84[kW] in the case the duty rate(D) changes from 0.08 to 0.3 under zero-current switching operating by a dissymmetry pulse width modulating control and the power conversion efficiency comes true the efficiency of 95[%]. Due to the result above, the ZCS PWM SEPP high frequency inverter will be effective as sources of an induction heating apparatus.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.241-243
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• 2008

This research presented the new zero-current switching pulse width modulation SEPP(Single Ended Push-Full)high frequency inverter for solving the problem of the zero-current SEPP high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the zero-current switching pulse width modulation SEPP high frequency inverter. The inverter circuit which is attempted by on-off operation of a switch has the reduction effect of the power loss due to a soft switching and a high frequency switching. And it confirmed that the power regulation is possible continuously from 0.25[kW] until 2.84[kW] in the case the duty rate(D) changes from 0.08 to 0.3 under zero-current switching operating by a dissymmetry pulse width modulating control and the power conversion efficiency comes true the efficiency of 95[%]. Due to the result above, the ZCS PWM SEPP high frequency inverter will be effective as sources of an induction heating apparatus.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.589-593
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• 2001

This paper presents a high frequency modulation electronic ballast for the metal halide lamp. As the proposed ballast operates in high frequency ranges (20kHz - 100kHz) and it can start up the lamp using the LC resonant circuit without external igniter, the proposed ballast is very compact. The proposed ballast is controlled with the modulated frequency in the range of 20kHz to 100kHz, and it has variable modulating frequencies between 200Hz and 2kHz in order to avoid the acoustic resonance phenomenon. In this paper, a new realtime acoustic resonance detection method is described and the experimental results with the proto-type ballast of 150W metal halide lamp with the dimming function are discussed.

• 전자공학회논문지SC
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• 제40권3호
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• pp.215-224
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• 2003

본 논문은 새로운 복합 변조방식에 의해 구동되는 메탈 할라이드 램프용 고주파 전자식 안정기에 관한 것이다. 제안하는 변조방법의 경우, 변조신호가 스위프되는 복합 주파수를 갖기 때문에, 일정한 주파수의 변조신호를 갖는 통상의 변조방법 보다 더욱 효과적으로 공명현상을 회피할 수 있다 차후 ASIC을 목적으로, 제안하는 안정기의 제어기는 마이크로프로세서를 사용하지 않고 EPLD만을 사용하여 설계하였다. 본 논문에서는 제안하는 변조방법의 구체적 알고리즘 및 제안하는 변조방법을 적용한 제어기프로토타입의 150 W 메탈할라이드 램프용 안정기로 수행된 실험결과를 기술하였다.

• 전기학회논문지
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• 제59권5호
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• pp.904-911
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• 2010

This paper presents the design of acoustic resonance free and over current limit during transient state consideration electronic ballast for 1.5kW Metal-Halide Lamp(MHL) that employs frequency modulation (FM) technique. The proposed ballast consists of a Full-Bridge(FB) rectifier, a passive power factor correction (PFC) circuit, a full-bridge inverter, an ignitor using LC resonance and a control circuit for frequency modulation. The frequency modulation technique is the most effective solution to eliminate acoustic resonance among other technique. It spreads power spectrum of lamp to reduce the supplied power spectrum under the energy level of eigen-value frequency. Moreover, the proposed ballast is simple and cost effective above conventional ballast. A new PFC circuit is proposed which combines with LCD type and PCSR filter. A new PFC circuit has higher PF and lower THD than conventional LCD type and secure high reliability. Finally, to protected switching components in transient state, the surge current into ballast is limited by increase the switching frequency. Performance of the proposed ballast was validated through computer simulation using Pspice, experimentation and by applying it to an electronic ballast for a prototype 1.5kW MHL.

• 센서학회지
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• 제16권5호
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• pp.342-348
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• 2007

A high-speed signal processor for Fabry-Perot interferometric sensors using modified ramp modulation is implemented. The main idea for the signal processing is to find a modulation waveform that could induce a linear frequency change in a laser diode to linearize the relationship between the optical phase shift and measurand. It is found that the waveform could be modeled as the addition of a linear term and an exponential term. A signal processor adopting modified ramp modulation technique is implemented and evaluated to find linearity, drift and random walk of $<{\pm}1.5%$, $0.4^{\circ}C$, $5.28{\times}10^{-4}^{\circ}C/{\sqrt{Hz}}$.

• 전자공학회논문지SC
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• 제39권3호
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• pp.228-238
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• 2002

본 논문은 메탈 할라이드 램프용 고주파 변조 방식 전자식 안정기의 디지털 제어기에 관한 것이다. 제안한 디지털 제어기에는 소프트 스타팅, 무부하 보호, 과전류 보호, 전력 제어 알고리즘이 포함되어 있다. 또한 제안한 디지털 제어기는 고주파 변조 제어 및 공명 현상회피 알고리즘을 수행한다. ASIC을 이용한 저가 양산을 위하여 제안한 제어기는 마이크로프로세서를 이용하지 않고 단지 FPGA만을 사용하여 설계하였다. 본 논문에서는 구체적인 디지털 제어 알고리즘들을 기술하였으며 프로토 타입의 150w 메탈 할라이드 램프용 전자식 안정기의 실험 결과를 나타내었다.

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.762-769
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• 2016

The dynamic modulation transfer function (MTF) for image degradation caused by sinusoidal vibration is formulated based on a Bessel function of the first kind. The presented method makes it possible to obtain an analytical MTF expression derived for arbitrary frequency sinusoidal vibration. The error obtained by the use of finite order sum approximations instead of infinite sums is investigated in detail. Dynamic MTF exhibits a stronger random behavior for low frequency vibration than high frequency vibration. The calculated MTFs agree well with the measured MTFs with the slant edge method in imaging experiments. With the proposed formula, allowable amplitudes of any frequency vibration are easily calculated. This is practical for the analysis and design of the line-of-sight stabilization system in the remote sensing camera.