• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.182-184
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• 2009

본 논문은 램프 점등을 위한 공진회로와 정상상태에서의 저주파수 구형파(low frequency square-wave) 인버터 전류 제어를 실현하는 HID 전자식 안정기에 풀브리지 인버터(FB)와 LC 필터를 제안한다. 점등은 LC필터의 공진주파수에서 풀브리지 인버터 제어에 의한 공진에 의해서 이루어지고, 점등 후에 회로는 풀브리지 제어에 의해 벅컨버터 저주파수 구형파 인버터로 동작한다. 점등이 일어나는 동안의 LC필터의 공진주파수는 ($f_o$=120kHz)이고, 고조파를 감소시키고 음향공명현상을 피하기 위한 벅컨버터스위칭 주파수($f_{sw}$=50kHz)를 선택하였다.

• Journal of the Korean Ceramic Society
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• v.45 no.7
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• pp.375-379
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• 2008

Redox behavior was observed in alkali alkaline earth silicate PDP (Plasma Display Panel) glass melts doped with sulfate and sulfide by square wave voltammetry (SWV). According to voltammograms produced at a temperature range of 1100 to $1400^{\circ}C$ and frequency range of 5 to 1000 Hz, both melts showed the same behavior in which there is one reduction peak at low frequency but another peak at an increase of frequency. Based on the frequency dependence of the peak current, self diffusivity of $S^{4+}$ was determined. Based on the temperature dependence of the peak potential, standard enthalpy (${\Delta}H^0$) and standard entropy (${\Delta}S^0$) for the reduction of $S^{4+}$ to $S^0$ were calculated.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.304-309
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• 2005

This paper presents an electronic ballast using a step down converter, a low frequency inverter for high intensity short-arc discharge lamp. The proposed ballast is composed of a full-wave rectifier, a step down converter operated as a current source with power regulation and a low frequency inverter with external ignition circuit. The ignition circuit generates high voltage pulse of $3{\sim}5[kV]$ peak, 130[Hz] periodically. Moreover, it is able to reignite at regular intervals by protective circuit. As experimental results on the test, acoustic resonance phenomenon is eliminated by operating the low frequency square wave voltage and current. Lamp voltage, current and consumption power are measured 123.8[V], 8.1[A] and 1,002[W], respectively. It was confirmed that the designed ballast operate the lamp with a constant power.

• Journal of Power Electronics
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• v.10 no.5
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• pp.451-460
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• 2010

This paper presents a new kind of digital control metal halide lamp electronic ballast. A zero-voltage-switch quasi-square-wave (ZVS-QSW) dual Buck converter is adopted here. In this paper, a digital control method is proposed to achieve ZVS for the converter. This ZVS can be realized during the whole working condition. Single-cycle-peak-current control is proposed to solve the problem of excessive inductor current during a low-frequency reversal transient. Power loop control is also realized and its consistency for different lamps is good. An AVR special microcontroller for a HID ballast is used to raise the control performance, and the low-frequency square-wave control method is adopted to avoid acoustic resonance. A 70W prototype was built in the laboratory. Experimental results show that the electronic ballast works reliably. Furthermore, the efficiency of the ballast can be higher than 92%.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1991.10a
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• pp.5-10
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• 1991

There are many articles about the HID lamps about it's characteristics and simulation methods for lamps design or ballast design. For the eletronic ballasts of HID lamps, There are some problems caused by acoustic resonance which destabilizes the arc of HID lamps. So, some studies suggest the methods to avoid it. For example, the methods to avoid it. For example, the methods suggested are high frequency driving over 100kHz, and mixed frequency driving which alternates high frequency and low frequency, and square wave driving etc. This study suggests the electronic ballast of HID lamps which solves the problems of acoustic resonance, and which can control the luminance by constant current boosted chopper of which frequency is 30kHz and by the sqarewave driving of which frequency is 55.5Hz. As follows, we have the good eletronic ballast for HID lamps which has the characteristics of a light weight, and a function of luminance control and a high quality luminosity and which saves electrical energy.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1992.11a
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• pp.11-15
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• 1992

Currently-using low-pressure lamps are usually drivel by the AC power supply. There are good and bad points according to high or low frequency in AC power driving type. For the low-pressure lamps, its efficiency increases and flicker decreases when it ignites at high frequency. So we already use the high-frequency electronic ballast of the low-pressure discharge lamps broadly. But there are EMI interference in high-frequency driving type because of giving the fluorescent lamp the high- frequency current. So recently, we have a tendency to compensate for that defects by DC driving method. As follows, we suggest pseudo DC discharging electronic bar lasts for fluorescent lamps which have the characteristics of high efficiency and no flicker by driving constant current boosted square wave.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.4
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• pp.37-42
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• 1984

In this paper, effective methods of symbol timing in a 9600 bps modem are presented. The symbol timing circuit consists of a square-low device followed by a high-Q narrow band-pass filter tuned to a symbol frequency. Also, the advantages of using a digital phase-tooted loop (DPLL) to suppress side tones are described, and statistical properties of timing wave are derived. In addition, the overall performances of the symbol timing circuit are verified by computer simulation.

• Journal of IKEEE
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• v.26 no.1
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• pp.95-103
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• 2022

In this paper, the efficiency of a sensorless method with square-wave injection for a low-cost inverter, so called B4 inverter is presented. This inverter comprises only 4 switches to reduce system cost. It is distinguished from the conventional B6 inverter that has 6 of switching elements. The B4 inverter, injected a 1 kHz of harmonic wave, has been modelled using the functions and library in Matlab/Simulink. This paper described each component of sensorless algorithm. Among them, the Notch Filter is used to extract the harmonic component of the phase current and a second-order low-pass filter was used to reduce the ripple of the estimated speed. It is shown through simulation that the rotor angle of a permanent magnet synchronous motor is detected by multiplying the current waveform extracted using the notch filter by the harmonic voltage. The feasibility of the proposed method is shown through Simulink simulation.

• Journal of Sensor Science and Technology
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• v.25 no.1
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• pp.8-12
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• 2016

A planar, light-weight, and low-cost notch filter structure is required for the KSTAR ECEI (Electron Cyclotron Emission Imaging) system to protect the mixer arrays from spurious plasma heating power. Without protection, this heating power can significantly degrade or damage the performance of the mixer array. To protect mixer arrays, a frequency selective surface (FSS) structure is the suitable choice as a notch filter to reject the spurious heating power. The FSS notch filter should be located between the lenses of the ECEI system. This paper presents a 170 GHz FSS notch filter for the KSTAR ECEI sensor application. The design of such an FSS notch filter is based on the single-sided square loop geometry, because that makes it relatively insensitive to the incident angle of incoming wave. The FSS notch filter exhibits high notch rejection with low pass-band insertion loss over a wide range of incident angles. This paper also reviews the simulated and measured results. The proposed FSS notch filter might be implemented in other millimeter-wave plasma devices.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.496-502
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• 2006

In this paper, we studied the development of the electronic ballast for 250W MH (Metal-Halide) lamps. We were able to improve the input power factor by using a PFC IC. To provide the lamp with the rated voltage required, we used the buck-type dc-dc converter. The stress of the switching devices in the inverter could be reduced by this method. To eliminate the acoustic resonance phenomena of MH lamps, the voltage of the lamp added the high frequency sine-wave to the low frequency square-wave by using the full bridge typed inverter. We have developed a simple igniter using the L and C elements. We could control the dimness of the lamp by varying the output voltage of the buck converter. The buck converter output voltage could be controlled by using a microprocessor.