• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.4
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• pp.652-658
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• 2006

This paper deals with an electronic ballast for hish intensity short-arc discharge lamps, which consists of a boost converter, 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 pulses of 130[Hz] up to 5 [kV]. A reignition circuit is equipped in the ballast, and it operates the lamp at a regular interval for protection when an ignition fails. Acoustic resonance phenomenon was eliminated by operating a low frequency square wave voltage and current. The measured lamp voltage, current and consumption power were 123.8 [V], 8.1 [A] and 1,002 [W], respectively. From the experiment, we confirmed that the prototype ballast operates the lamp with a constant power.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.5
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• pp.410-415
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• 2001

This paper proposes a new control scheme for the power factor improvement of DC power regenerating systems, which can regenerate the excessive DC power from DC bus line to AC supply in substations for traction systems. From the viewpoint of both power capacity and switching losses, the system is designed on the basis of three-phase square-wave inverters and composed of two inverters, zig-zag connected output transformers, and an AC filter. The output voltages of the regenerating system are not sinusoidal. However, regenerated complex power is analyzed on the basis of fundamental components and thus the reactive power produced by harmonics is not considered. Therefore, it is needed a new control scheme capable of controlling the reactive power nearly to zero even for nonsinusoidal cases. To verify the validity of the proposed control scheme, computer simulations are carried out. And the results show that the power factor is theoretically higher than 0.99.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.5
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• pp.106-111
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• 2007

After the semiconductor processing, wafer is attracted by ESC(Electrostatic Chuck) with remaining electric charge. That causes too many problems for examples, sliding of wafer, popping or broken. This paper presents the model of ESC for silicon wafer, which is modeled by electrical circuit component such as capacitor. The simulations using PSpice result in the phenomenon of silicon wafer was charged by ESC. In this paper we suggest the discharging method. for wafer.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.68-72
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• 2004

In this paper, the energy conversion theory of the linear actuator deals with the temperature characteristic analysis with verifying temperature of linear Actuator system This model of linear actuator has winding part and mechanical spring, and a plunger. This paper proposed and experimented the linear Actuator(LA) by using finite difference equation(FDE). The experimental result represented the temperature T1 and T2 which remarks Tl is a center of magnetic road inside of actuator winding part, and T2 is a surface of actuator winding part. And the temperature characteristic of the actuator winding part are experimented by the digital temperature meter TECPEL 322.

• Journal of IKEEE
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• v.24 no.2
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• pp.579-585
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• 2020

In this study, we used byte-inversion transmission method to prevent the flicker of lighting source in a visible light data communication link. In the transmitter, the non-return-to-zero (NRZ) signal with 9.6 kbps was on-off keying (OOK) modulated with a 100 kHz square wave carrier and byte-inversion signal was added after each byte to make the average optical power of the light-emitting diode (LED) constant. In the receiver, we used a band-pass filter to eliminate the interference of the 120 Hz noise which was induced from the adjacent light lamps, and an OOK demodulator to recover the original NRZ signal This scheme is useful in constructing wireless data networks using the illumination of visible light lamps.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.479-482
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• 2001

This paper proposes a modified $\alpha$ conduction mode for controlling the output voltage magnitude of three-phase square-wave VSIs with an R-L load. From the viewpoint of both power capacity and switching losses, three-phase square-wave inverters are now used in most high power systems. When the square-wave VSI is driven with $\alpha$ conduction mode to control the magnitude of output voltages, interval over than half period is operated with $180^{\circ}$ conduction mode and the other interval with $120^{\circ}$ conduction mode. In $120^{\circ}$ conduction mode operation, two output terminals are connected to DC supply and the third one remains open. The potential of this open terminal will depend on the load characteristics and is unpredictable except the case of pure resistive loads. To cope this problem, we propose the modified α conduction mode.

• Journal of the Korean Magnetics Society
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• v.12 no.3
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• pp.109-116
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• 2002

We designed the flyback planar transformer, which had 8 W capacity, with 70 V input voltage and 8.2 V output voltage for the establishment of design method and the confirmation of application possibility. The numerical value of inductance measured under the switching frequency of 120 kHz was 1650 $\mu$H, which was the inductance efficiency of'85∼87% against theoretical value. The A.C. resistance of primary and secondary coil was 4.2 Ω and 0.25 Ω respectively, On the other hand, the quality factor for each wound numbers showed quite a high value of 158 and 75 respectively. And the Coupling Factor was 0.96∼0.97 under 120 kHz switching frequency. The inductance rapidly increased as the thickness of the core plane increased until it became 1.4 mm but under the thickness more than 1.4 mm, there was no substantial change. Therefore, the critical value of the plane thickness of core was 1.4 mm. And the shape of the output wave of the planar transformer at 70V input voltage was a stable square wave.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1051-1058
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• 2014

This paper presents a Electrical characteristics of the Memristor device using the PSPICE for circuit analysis. After making macro model of the Memristor device for circuit analysis, electric characteristics of the model such as time analysis, frequency and DC analysis according to the input voltage were performed by PSPICE simulation. Also, we made simple circuits of memristor series and parallel structure and analyzed the simulated SPICE results. Finally, we made a memristor-capacitor (M-C) circuit. charge and discharge characteristics were analyzed. In case of input pulse signal of 250 Hz, the Memristor-capacitor circuit showed delay time of 0.6ms, rising time of 0.58 ms and falling time of 1.6 ms.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.51-51
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• 2009

Thin Cross 초음파모터의 구조는 그림 1(a)와 같이 크로스형태의 얇은 스테이터에 윗면과 아랫면에 각각 8개의 압전세라믹이 부착된 형태이다. 압전세라믹의 분극방향은 로터와 접촉하는 스테이터의 중심부인 네 개의 타 점에서 순차적인 타원변위가 생성되도록 결정된다. 유한요소해석프로그램인 ATILA 5.2.4를 사용하여 최적설계된 모델을 제작하였고, 푸쉬풀 게이지, x-y 스테이지, rpm 메타, 토크 게이지를 이용하여 구동시스템을 구성하였다. 그림 1(b)는 마이크로컨트롤러(ATmega)를 이용한 구동 드라이버를 보여준다. 한 주기에서 1/4분주의 순차적인 네 개 의 구형파를 생성하고, 이를 push-pull회로를 통하여 90도의 위상차가 나는 정현파를 생성하여 초음파 모터의 구동 전원으로 사용한다. 피드백 회로인 맨코더와 AD 컨버터는 정속도 운전을 위해서 사용되었다. 제안된 구동드라이버를 이용하여 측정한 결과, 기존의 제품화된 드라이버와 비교하여도 특성의 큰 차이를 보이지 않았으며 피드백 회로를 통하여 부하변화에 따른 속도의 극심한 변화를 비교적 안정화 시킬 수 있었다. 입력전압을 증가시킬수록 속도는 선형적인 증가를 보였고 토크는 이와 반대로 감소하는 특성을 보였다. 피드백 제어회로가 없는 경우에는 프리로드 변화에 따른 극심한 속도 변화를 보였고, 피드백 제어를 하였을 경우에는 0.2~0.4[N]의 범위에서 정속도 운전이 가능함을 확인하였으며, 장시간의 운전에도 온도 및 속도특성이 안정적인 특성을 보였다.

• The Journal of Korean Association of Computer Education
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• v.10 no.6
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• pp.69-77
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• 2007

In this paper we implement main functions of electronic measuring devices, which are essential to design electric/electronic virtual laboratories on the Web. The implemented virtual electronic measuring devices such as virtual analog multimeter(VAM), virtual function generator(VFG), virtual oscilloscope(VOSC) enable the learners to perform the virtual experiments on the Web by simple mouse clicks. In order to show their validity virtual experiments for understanding how to use them are designed. The virtual experiments for measuring resistance(OHM), AC/DC Voltage(ACV/DCV) and DC Current(DCA) by the VAM are illustrated. In addition, the learners can change the frequency of the signal generated from the VFG and measure by the VOSC several types of the signals generated from the VFG such as triangular, pulse, sinusoidal waveforms. The VOSC can measure voltage and current through two channels of it and provide the learners with additional functions such as zooming, trigger, cursor, summing of waveforms. Since the virtual electronic measuring devices have been implemented as forms of Java classes, various types of applications are available according to the structures of virtual laboratories.