• Title/Summary/Keyword: peak current

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Design of the Detection Circuitry for the Characteristics of Micromachined Vibrating Gyroscope (미세가공 진동형 자이로스코프의 특성 감지 회로의 설계에 관한 연구)

  • U, Yeong-Sin;Byeon, Gwang-Gyun;Seo, Il-Won;Seong, Man-Yeong
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.10
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    • pp.687-692
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    • 1999
  • A new technique to measure low level capacitance variations of the gyroscope is proposed and verified by computer simulation. It is based on the new CV(capacitance-voltage) converter circuit biased by dc current source and the peak detector without low pass filter. The CV converter biased by dc current source provides good signal-to-noise ratio and this setup of the detection circuitry without low pass filter makes it possible to provide short settling time, that is, higher speed of measurement and wide operation range if only a few parameters are adjusted. The key parameters that affect the performance of the detection circuitry are illustrated and computer simulation results are presented. The demonstrated detection circuitry shows linear response from 10 fF to 130 fF at 10 kHz and shows good linearity.

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An Analysis Method for the Transient Ground Impedance Using Variable Frequency Current and Lightning Impulse (가변주파수 및 임펄스 전류를 이용한 과도접지임피턴스 분석)

  • Cho, Sung-Chul;Eom, Ju-Hong;Lee, Tae-Hyung
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2007.11a
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    • pp.231-234
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    • 2007
  • This paper presents an analysis method of transient ground impedance using the lightning impulse and variable frequency currents. The transient ground impedance strongly depends on the configuration and size of grounding electrodes and the shapes of impulse currents, and the inductance of grounding electrodes has a significant affect on the transient impedance of the grounding system. There are some differences between the effective impulse ground impedance which was introduced some papers and the transient ground impedance. The transient ground impedance measured from the peak value of impulse voltage and the peak value of impulse current is more reliable than the effective impulse ground impedance.

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Comparison of Simulated PEC Probe Performance for Detecting Wall Thickness Reduction

  • Shin, Young-Kil;Choi, Dong-Myung;Jung, Hee-Sung
    • Journal of the Korean Society for Nondestructive Testing
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    • v.29 no.6
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    • pp.563-569
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    • 2009
  • In this paper, four different types of pulsed eddy current(PEC) probe are designed and their performance of detecting wall thickness reduction is compared. By using the backward difference method in time and the finite element method in space, PEC signals from various thickness and materials are numerically calculated and three features of the signal are selected. Since PEC signals and features are obtained by various types and sizes of probe, the comparison is made through the normalized features which reflect the sensitivity of the feature to thickness reduction. The normalized features indicate that the shielded reflection probe provides the best sensitivity to wall thickness reduction for all three signal features. Results show that the best sensitivity to thickness reduction can be achieved by the peak value, but also suggest that the time to peak can be a good candidate because of its linear relationship with the thickness variation.

A Unity Power Factor Electronic Ballast for Fluorescent Lamp having Improved Valley Fill and Valley Boost Converter (개선된 밸리필과 밸리용 승압형 변환기를 결합한 고역률 형광등용 전자식 안정기)

  • Youn, Yong-Sik;Chae, Gyun;Cho, Gyun-Hyeong
    • Proceedings of the KIEE Conference
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    • 1997.07f
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    • pp.2002-2006
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    • 1997
  • A new PF correction topology, Improved Valley Fill (IVF) with Valley Boost Converter (VBC) used in the electronic ballast for fluorescent lamp is presented. The IVF can adjust the valley voltage higher than half the peak line voltage. Hence, there is no pulsating line current around the line voltage peak, PF and THD are significantly improved. The VBC is added to the IVF to achieve unity PF and to increase the valley voltage. The measured PF and THD for a prototype electronic ballast are 0.997 and 5%, respectively, and the lamp current CF is as low as 1.5

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A Study of Characteristics of the Wire-cut EDM Process in Aluminum Alloys (알루미늄합금의 와이어 컷 방전기공 특성에 과한 연구)

  • Lyu, Sung-Ki;An, Soon-Geon
    • Journal of the Korean Society of Safety
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    • v.19 no.2
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    • pp.21-25
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    • 2004
  • This study deals with the characteristics of wire-cut EDM(Electrical Discharge Machining)process in aluminum alloys. Besides 2 series and 7 series of aluminum alloys for aerospace applications, porous aluminum is tested, which is used for sound absorbing matherial and interior and exterior material of building. Jinyoung JW-30 wire cutting machine was used in this experiment. Tap wate passed a filter and ionization was used as the discharging solution. An immerision method was applied as a cooling method because it separates chips effectively and machinability is good even with low value of electric current. The speed of fabrication was estimated by measuring the travel distance of the work piece and time spent for the movement. As pulse-on-time increased the fabrication speed decreased. On the other hand, as peak voltage of peak current increased the fabrication speed increased. In general 7075 aluminum alloy resulted in higher fabrication speed.

Ground ing Impedance Characteristics of Ground Rods in frequency Domain (주파수 영역에서 봉상전극의 접지임피던스 특성)

  • Lee, Hyung-Soo;Shim, Keon-Bo;Kim, Kyung-Chul;Choi, Jong-Kee;Park, Sang-Man
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2005.05a
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    • pp.248-253
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    • 2005
  • Although DC ground resistance is a good index of grounding performance for grounding electrodes, it does not reflect the grounding performance during transient state. Besides, impulse ground impedance, which is defined by a ratio of the peak value of transient ground potential rise to the peak value of impulse current, cannot be an absolute index due to its dependence on impulse current shape. In this paper, ground impedance of various rod-type ground electrodes has been measured in frequency domain ranging from 1 Hz to hundreds of kHz. Equivalent circuit models of the ground rod have been identified from the measured values of ground impedance in frequency domain.

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A study of the initial position estimation of an interior permanent magnet synchronous motor (매입형 영구자석 동기전동기의 초기위치 추정에 관한 연구)

  • Joung, Woo-Taik;Lee, Jeong-Hum;Kim, Dai-Hyun;Choi, Yang-Kwang;Kim, Young-Seok
    • Proceedings of the KIEE Conference
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    • 2004.10a
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    • pp.46-48
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    • 2004
  • Recently, the study of sensorless drive of IPMSM is coming to be active. In sensorless drive, because the wrong estimation of the initial rotor position brings about the decrease of the starting torque, or a temporary reverse revolution, it is important to know the exact importation of the initial rotor position. In this paper, the initial rotor position estimation method is based on the current peak measured by applying the pulsewise voltage and the current peak is changed according to the rotor position owing to the saliency of the rotor. The effectiveness of the proposed algorithm is verified by the experimental results.

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Grid-Connected Peak Load Compensation System Based on Lithium Polymer Battery Energy Storage System

  • Jung, Doo-Yong;Ji, Young-Hyok;Lee, Su-Won;Won, Chung-Yuen;Seo, Kwang-Duk;Jung, Yong-Chae
    • Proceedings of the KIPE Conference
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    • 2009.11a
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    • pp.265-267
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    • 2009
  • we proposed a grid connected peak load compensation system with high discharge current characteristics based on lithium polymer battery for development of the next generation power-station. The lithium polymer battery has faster discharge current characteristics than conventional battery, so that can compensate high active power demanded by load in a short time using the low capacity battery bank. Therefore, it is possible to control power leveling of grid by measuring storage energy of battery and active power which is needed from load. The validity of proposed system was verified through the simulation and experiment.

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Latitude-Independent Pc5 Geomagnetic Pulsations Associated With Field Line Resonance

  • Seon, Suk-Gyeong;Ki, Gwan-Hyeok;Le, Dong-Hun
    • Bulletin of the Korean Space Science Society
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    • 2004.04a
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    • pp.40-40
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    • 2004
  • The latitude-independent Pc5 pulsations with a spectral peak at -3 mHz were observed with IMAGE and SAMNET magnetometer away, ranging from -47$^{\circ}$ to -77$^{\circ}$geomagnetic latitudes, in the morning sector (0700-1000 local time) during an interval of 30 minutes on April 29, 2001. The spectral amplitude had a local peak at -67$^{\circ}$, where a sudden phase change of -180$^{\circ}$ is found. A vortical equivalent ionospheric current structure centered at latitude between 67$^{\circ}$ and 71$^{\circ}$ was observed during the Pc5 pulsations and the rotational sense of the current vortex was reversed for one cycle of the pulsation. (omitted)

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Zero Voltage and Zero Current Switching Full Bridge DC-DC Converter Using Novel Secondary Active Clamp (새로운 2차측 능동 클램프회로의 영전압 영전류 스위칭 Full Bridge DC-DC 컨버터)

  • Kim, Byung-Chul;Kim, Hyung-Gon;Kim, Kwang-Heon
    • Proceedings of the KIEE Conference
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    • 1999.11a
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    • pp.13-15
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    • 1999
  • The zero voltage and zero current switching(ZVZCS) full bridge (FB) PWM converter using secondary active clamp is characterized by high efficiency, good ZVZCS characteristic, simple topology and low cost. But at the period for discharge of the secondary clamp capacitor, peak pulses and ringing pulse occur in rectified secondary side of the converter. In this paper, a novel secondary active clamp circuit for the ZVZCS FB PWM converter is proposed and a 50 kHz, 500 W prototype converter was experimented for verification of the converter characteristics. It was verified that high voltage peak pulses and ringing pulse on secondary rectified waveforms of the converter are decreased effectively.

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