• Title/Summary/Keyword: CONDITION FACTOR(K)

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A Continuous Conduction mode/Critical Conduction Mode Active Power Factor Correction Circuit with Input Voltage Sensor-less Control (입력전압을 감지하지 않는 전류연속/임계동작모드 Active Power Factor Correction Circuit)

  • Roh, Yong-Seong;Yoo, Changsik
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.8
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    • pp.151-161
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    • 2013
  • An active power factor correction (PFC) circuit is presented which employs a newly proposed input voltage sensor-less control technique operated in continuous conduction mode (CCM) and critical conduction mode (CRM). The conventional PFC circuit with input voltage sensor-less control technique degrades the power factor (PF) under the light load condition due to DCM operation. In the proposed PFC circuit, the switching frequency is basically 70KHz in CCM operation. In light load condition, however, the PFC circuit operates in CRM and the switching frequency is increased up to 200KHz. So CCM/CRM operation of the PFC circuit alleviates the decreasing of the PF in light load condition. The proposed PFC controller IC has been implemented in a $0.35{\mu}m$ BCDMOS process and a 240W PFC prototype is built. Experimental results shows the PF of the proposed PFC circuit is improved up to 10% from the one employing the conventional CCM/DCM dual mode control technique. Also, the PF is improved up to 4% in the light load condition of the IEC 61000-3-2 Class D specifications.

A Fatigue Related Equation with Shape and Loading Factors Representing Effect of Thickness in Al 2024-T3 Alloy Sheet (판재 Al 2024-T3 합금재료의 두께효과를 나타내는 형상인자 및 하중인자에 의한 피로관계식)

  • Kim, Seung-Gwon;Lee, Ouk-Sub;Jang, Joo-Sup
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.1
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    • pp.141-146
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    • 2012
  • Aluminum alloys have been used with various thicknesses suitable for light weight of structure. It is known that the thickness effect of material is an important factor affecting fatigue crack propagation under constant fatigue stress condition. In this work, we presented the behavior of fatigue crack propagation in thin plate compared to thick plate Al 2024-T3 alloy with referred thickness effect in a correlative equation determined by the shape factor and the loading factor. We chose two factors that are used in the correlative equation with considering that the experiments were carried out under a constant fatigue stress condition. The thickness ratio of thin plate compared to thick plate and the equivalent effective stress intensity factor ratio depending on thickness were chosen as shape and loading factors. A correlative equation is utilized to determine the equivalent effective stress intensity factor range of thin plate and identify the degree of increasing phenomenon of fatigue life in thin plate compared to thick plate.

Determination of Efficient Operating Condition of UV/H2O2 Process Using the OH Radical Scavenging Factor (수산화라디칼 소모인자를 이용한 자외선/과산화수소공정의 효율적인 운전 조건도출)

  • Kim, Seonbaek;Kwon, Minhwan;Yoon, Yeojoon;Jung, Youmi;Hwang, Tae-Mun;Kang, Joon-Wun
    • Journal of Korean Society of Environmental Engineers
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    • v.36 no.8
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    • pp.534-541
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    • 2014
  • This study investigated a method to determine an efficient operating condition for the $UV/H_2O_2$ process. The OH radical scavenging factor is the most important factor to predict the removal efficiency of the target compound and determine the operating condition of the $UV/H_2O_2$ process. To rapidly and simply measure the scavenging factor, Rhodamine B (RhB) was selected as a probe compound. Its reliability was verified by comparing it with a typical probe compound (para-chlorobenzoic acid, pCBA); the difference between RhB and pCBA was only 1.1%. In a prediction test for the removal of Ibuprofen, the RhB method also shows a high reliability with an error rate of about 5% between the experimental result and the model prediction using the measured scavenging factor. In the monitoring result, the scavenging factor in the influent water of the $UV/H_2O_2$ pilot plant was changed up to 200% for about 8 months, suggesting that the required UV dose could be increased about 1.7 times to achieve 90% caffeine removal. These results show the importance of the scavenging factor measurement in the $UV/H_2O_2$ process, and the operating condition could simply be determined from the scavenging factor, absorbance, and information pertaining to the target compound.

Evaluation of Dose Reduction and Maintaining Image Quality according to Exposure Factors of Cone Beam Computed Tomography (콘빔전산화단층촬영에서 노출 조건에 따른 화질 유지 및 선량 감소에 대한 평가)

  • Han, Jin-Woo
    • Journal of the Korean Society of Radiology
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    • v.14 no.4
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    • pp.353-360
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    • 2020
  • This research aims at suggesting exposure condition that shows maintaining the value of the physical image quality factor by decreasing tube voltage and tube current from the standard exposure condition(80 kV, 7 mA) of a CBCT apparatus. To measure the value of the physical image quality factor, modular transfer function(MTF) was analyzed and dose-area product(DAP) was used for the measurement of exposure dose. CBCT images of a Sedentex IQ phantom were obtained under 15 exposure conditions of different combination of tube voltage(80, 78, 76 kV) and tube current(7, 6, 5, 4, 3 mA) and MTF 10 was calculated under each exposure conditions. There were no significant differences in MTF 10 under 80 kV-6 mA, 80 kV-5 mA exposure conditions in comparison with standard exposure condition. Based on the results of this research, 80 kV-5 mA condition are expected to be able to reduce exposure dose with maintaining the value of the physical image quality factor of the standard exposure condition.

Propose to new Method determining level of Noise Factor of Taguchi Method (다구찌 기법의 잡음인자 수준 정하는 기법 제안)

  • Ree, Sang-Bok
    • Proceedings of the Korean Society for Quality Management Conference
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    • 2009.10a
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    • pp.317-323
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    • 2009
  • In this paper, we propose new methods which is to determine level of noise factor. Even Taguchi give level of noise factor which is best(or maximum) and worst(or minimum) condition, we give level of noise factor which is representative value by observing noise factor frequency. Sometimes level of noise factor is given one, two and three. We know this method is more fit in real fields.

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Method determining level of Noise Factor of Taguchi Method under various probability distribution (다양한 확률분포 하에서 다구찌 기법의 잡음인자 수준 정하는 기법)

  • Ree, Sang-Bok
    • Journal of Korean Society for Quality Management
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    • v.37 no.4
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    • pp.10-15
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    • 2009
  • In this paper, we propose new methods which is to determine level of noise factor. Even Taguchi give level of noise factor which is best(or maximum) and worst(or minimum) condition, we give level of noise factor which is representative value by observing noise factor frequency. Sometimes level of noise factor is given one, two and three. We know this method is more fit in real fields.

Characteristics of Insulation Aging in High Voltage Cables (고압케이블의 절연열화 특성)

  • Kim, Kyeong-Yeol
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.88-88
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    • 2010
  • High Voltage cross-linked polyethylene (XLPE) cables are widely used in a thermal power plant. These cables had been in service for 26 years. The insulation condition of six 6 kV XLPE cables was estimated by insulation diagnostic analyzer (IDA) with voltage amplifier. IDA was measured dissipation factor and capacitance of the whole cable as a function of frequency and voltage. This system measures in the frequency range from 0.1 to 10 Hz at each voltage level. Six XLPE cables are judged good condition, but three cables are analyzed at an aged condition.

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Design of Interleaved Boost Power Factor Preregulator (Interleaved 승압형 역률 전치보상 컨버터의 설계)

  • Heo, T.W.;Noh, T.G.;Jung, J.R.;Ahn, I.M.;Son, Y.D.;Woo, J.I.
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.1123-1125
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    • 2002
  • In this paper, interleaved boost converter is applied as a pre-regulator in switch mode power supply. Interleaved Boost Power Factor Preregulator (IBPFP) can reduce input current ripple as a simple voltage control loop only without inner current loop, because input current is divided each 50% by two switching devices. IBPFP can be classified as three cases from duty ratio condition in continuous current mode and be carried out state space averaging small signal modeling. According to modeling, the PID controller is applied and voltage control loop is constructed for suitable design condition. From frequency domain analysis, it is verified that control system is satisfied with design condition of switch mode power supply.

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Small Punch Test of TRIP Steel Charged with Hydrogen under Different Electrolyte Condition (다른 전해질분위기에서 수소주입시킨 TRIP강의 SP시험)

  • Kim, Kwang-Sig;Yoo, Kwang-Hyun;Park, Jae-Woo;Kang, Kae-Myung
    • Journal of the Korean Institute of Gas
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    • v.19 no.1
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    • pp.64-70
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    • 2015
  • In order to evaluate the degree of hydrogen embrittlement of TRIP steels charged with hydrogen according to varying the current density and the charging time under acid and alkaline electrolyte conditions were tested by small punch test. The results of SP test showed that the degree of hydrogen embrittlement at acid electrolyte condition was more effective factor compared to that of alkaline electrolyte condition. Therefore, all of the charging time and the charging current density were at the condition of acid electrolyte appeared as the main factor of the degree of hydrogen embrittlement in the condition of acid electrolyte. But, it was considered that the charging time compared to the charging current density at the condition of alkaline electrolyte was more effective factor to raise the degree of hydrogen embrittlement.

Chiral Separation of Ibuprofen by Supercritical Fluid Chromatography (초임계유체 크로마토그래피를 이용한 Ibuprofen의 키랄분리)

  • 한순구;노경호
    • KSBB Journal
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    • v.19 no.4
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    • pp.263-268
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    • 2004
  • The separation method using chiral stationary phase in preparation of chiral compound was wildly used, but in this work, supercritical fluid chromatography was suggested in the stability to resolve the chiral mixtures. To determine the optimum operating condition of the racemic ibuprofen, the retention factor and resolution with change in pressures, temperatures and the contents of IPA % (vol.) in CO$_2$ were investigated. The retention factor was decreased with increase in pressure and decrease in temperature. The factor was also influenced by the content of IPA in mobile phase, while the resolution was worse with a increase in IPA %. From the experimental results, the desirable separation condition was 130 bar, 311.15 K and 4% IPA in CO$_2$. Compared to the asymmetric peak shape by liquid chromatography, that of supercritical fluid chromatography was symmetric which was a favorable condition for preparative separation.