• Title/Summary/Keyword: Input Current Improvement

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Improvement of Switching Converter's Input Wave Using VIENNA Rectifier (VIENNA 정류기를 이용한 스위칭 컨버터의 입력 파형 개선)

  • Jung, Hun-Sun;Choi, Jae-Ho;Chung, Gyo-Bum
    • Proceedings of the KIEE Conference
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    • 2007.04c
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    • pp.201-204
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    • 2007
  • This paper proposes a improvement of switching converter's input wave form using VIENNA Rectifier(three-phase three-switch three-level PWM Rectifier). VIENNA Rectifier is based on the combination of a three-phase diode bridge and dc/dc boost converter. It can be available to get sinusoidal mains current, and low-blocking voltage stress on rower transistors. In addition, it can control output voltage.

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Efficiency Improvement of VVCF-Induction Motor Drives with Counter EMF Estimation (역기전력 추정에 의한 VVCF-유도전동기 시스템의 운전효율개선)

  • Moon, Sang-Chun;Lee, Seung-Chul;Jeong, Seung-Gi
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.271-273
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    • 1995
  • This paper proposes the efficiency improvement method of vvcf-induction motor drives, which operates always at rated speed, regardless of load conditions, with counter emf estimation. The counter emf is estimated by detecting the fundamental component of motor input current, which is employed in speed control algorithm through the comparison with the actual counter emf during the nonconduction interval. The input power reduction by speed control is confirmed through simulations and experimental results.

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A Study on Performance Improvement of Detecting Current of the Norton Amplifier (노튼 증폭기의 전류검출성능 개선에 관한 연구)

  • Kwon, Sung-Yeol;Lee, Hyun-Chang;Lee, Kyu-Tae
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.3
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    • pp.185-191
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    • 2018
  • In this paper, an improved Norton amplifier is proposed and the problems caused by the current input in the Norton amplifier, which has advantages in current transmission, are analyzed. The output of the voltage follower consisting of an operational-amplifier with constant output voltage characteristics is used as an input terminal of the proposed circuit. It is configured to detect the power supply current passing through the voltage follower and extract the current from the input terminal. The performance of the improved Norton amplifier is verified at experiment according to the input current. The results are compared with conventional Norton amplifier. Consequently, the input offset voltage, which is a problem in the conventional Norton amplifier, was removed in the proposed circuit. In addition, the average error of the output voltage with respect to the input current was reduced to 4.755%. It is verified that the characteristics of the proposed circuit are improved.

Neuro-Fuzzy Contro of Weld Pool Size in Arc Welding Robot System (1st Report : Fuzzy Control of Weld Pool Size) (아크용접 로보트시스템에서 용융지크기의 뉴로-퍼지 제어)

  • Jeon, Euy-Sik
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.6 no.4
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    • pp.89-95
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    • 1997
  • Welding technique is widely applied to general industry such as pressure vessel for chemical plant, pipe system, heavy industry, and automobile. There are some points which must be considered when robot system is used in welding automation process for productivity improvement. Welding quality is governed by heat input, and this quantity can be different according to shape, property, and thick of material . For desired heat input , weld input parameters such as welding voltage, current, and welding velocity must be determined with those consideration. Until now these parameters have been determined mainly by experience of operator. In this study, the size of welding zone was predicted by fuzzy rules were constructed from the relation between welding variables and weld pool size. Inverse model method which welding control input for welder is determined with optimum voltage and current by fuzzy controller is validatied by computer simulation.

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ESD damage mechanism of CMOS DRAM internal circuit and improvement of input protection circuit (정전기에 의한 CMOS DRAM 내부 회오의 파괴 Mechanism과 입력 보호 회로의 개선)

  • 이호재;오춘식
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.12
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    • pp.64-70
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    • 1994
  • In this paper, we inverstigated how a parricular internal inverter circuit, which is located far from the input protection in CMOS DRAM, can be easily damaged by external ESD stress, while the protection circuit remains intact. It is shown in a mega bit DRAM that the internal circuit can be safe from ESD by simply improving the input protection circuit. An inverter, which consists of a relatively small NMOSFET and a very large PMOSFET, is used to speed up DRAMs, and the small NMOSFET is vulnerable to ESD in case that the discharge current beyond the protection flows through the inverter to Vss or Vcc power lines on chip. This internal circuit damage can not be detected by only measuring input leakage currents, but by comparing the standby and on operating current before and after ESD stressing. It was esperimentally proven that the placement of parasitic bipolar transistor between input pad and power supply is very effective for ESD immunity.

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Improvement of input power factor on single phase full-bridge PWM AC/DC Converter (단상 full-bridge PWM AC/DC 콘버어터의 입력 역율개선)

  • Kim, Hyun-Soo;Park, Sung-Jun;Byun, Young-Bok;Kim, Kwang-Tae;Kwon, Soon-Jae;Kim, Cheul-U
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.255-257
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    • 1995
  • Many new electronic products are required to have a unity power factor and a distortion free input current waveform. In this parer, a high performance single phase AC/DC converter with input power factor correction is proposed. And each parameters are determined. Proposed control strategy has many advantages which include two Quadrants operation, simplified control circuit, high performance features and continuous Input current. The experimental results are included to verify the validity of this approach.

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Enhanced Voltage Gain Single-Phase Current-Fed qZ-Source Inverter (전압 이득이 향상된 단상 전류형 qZ-소스 인버터)

  • Shin, Hyun-Hak;Cha, Hon-Nyong;Kim, Heung-Geun
    • The Transactions of the Korean Institute of Power Electronics
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    • v.18 no.4
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    • pp.305-311
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    • 2013
  • This paper proposes a performance improvement of existing single-phase current-fed qZ-Source inverter. Voltage gain of the traditional voltage-fed full-bridge inverter and single-phase current-fed qZ-source inverter is only equal to or smaller than input voltage. The proposed inverter can obtain twice higher voltage gain than the single-phase current-fed qZ-Source inverter by adding an extra switch and a capacitor in the circuit. In addition, the proposed inverter shares the common ground between dc input and ac output voltage. Therefore, the proposed inverter can eliminate the possible ground leakage current problem when it is used for grid-tied photovoltaic inverter system. A 120 W prototype inverter is built and tested to verify performances of the proposed inverter.

A New-Half Bridge Converter without DC offset of magnetizing current

  • Cho, Kyu-Min;Oh, Won-Sik;Moon, Gun-Woo
    • Proceedings of the KIPE Conference
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    • 2007.07a
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    • pp.147-149
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    • 2007
  • A new half bridge converter without DC offset of magnetizing current is proposed. The proposed half bridge converter can realize no DC offset of magnetizing current as well as no circulating current, and guarantee ZVS operation. Therefore it has high efficiency and high power density, especially in wide input range. The operational principle, DC conversion ratio and ZVS analysis are presented. Experimental results demonstrate that the proposed converter can achieve a significant improvement in the efficiency.

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Air-Conditioner Power Source Device to Meet the Harmonic Guide Lines (고조파 규제값에 적합한 에어컨 전원장치)

  • Mun, Sang-Pil;Park, Yeong-Jo;Seo, Gi-Yeong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.10
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    • pp.581-586
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    • 2002
  • To improve the current waveform of diode rectifiers, we propose a new operating principle for the voltage-doubler diode rectifiers. In the conventional voltage-doubler rectifier circuit, relatively large capacitors are used to boost the output voltage, while the proposed circuit uses smaller ones and a small reactor not to boost the output voltage but improve the input current waveform. A circuit design method is shown by experimentation and confirmed simulation. The experimental results of the proposed diode rectifier satisfies the harmonic guide lines. A high input power factor of 97(%) and an efficiency of 98[%] are also obtained. The new rectifier with no controlled switches meet the harmonic guide lines, resulting in a simple, reliable and low-cost at-to dc converters in comparison with the boost-type current-improving circuits. This paper proposes a nonlinear impedance circuit composed by diodes and inductors or capacitors. This circuit needs no control circuits and switches, and the impedance value is changed by the polarity of current or voltage. And this paper presents one of these applications to improve the input current of capacitor input diode rectifiers. The rectifier using the nonlinear impedance circuit is constructed with four diodes and four capacitors in addition to the conventional rectifiers, that is, it has eight diodes and five capacitors, including a DC link capacitor. It makes harmonic components of the input current reduction and the power factor improvement. Half pulse-width modulated (HPWM) inverter was explained compared with conventional pulse width modulated(PWM) inverter. Proposed HPWM inverter eliminated dead-time by lowering switching loss and holding over-shooting.

A Study on the Power Factor Improvement of Single-Phase Bridgeless Voltage Doubler Converter (단상 브리지리스 배전압 변환기의 역률 개선에 관한 연구)

  • Koo, Do-Yeon;Kim, Dong-Wook;Lim, Seung-Beom;Hong, Soon-Chan
    • Proceedings of the KIPE Conference
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    • 2011.11a
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    • pp.169-170
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    • 2011
  • PFC(Power Factor Correction) converters are commonly designed for CCM(Continuous Conduction Mode). However, DCM(Discontinuous Conduction Mode) appears in the input current near the ZCP(Zero Crossing Point) at light loads, resulting in input current distortion. It is caused by inaccurate average current values obtained in DCM. This paper studies a simple digital control scheme that can be operated in both CCM and DCM with minimal changes to the CCM average current control structure.

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