• 제목/요약/키워드: duty efficiency

검색결과 448건 처리시간 0.026초

Design Methodology for Optimal Phase-Shift Modulation of Non-Inverting Buck-Boost Converters

  • Shi, Bingqing;Zhao, Zhengming;Li, Kai;Feng, Gaohui;Ji, Shiqi;Zhou, Jiayue
    • Journal of Power Electronics
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    • 제19권5호
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    • pp.1108-1121
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    • 2019
  • The non-inverting buck-boost converter (NIBB) is a step-up and step-down DC-DC converter suitable for wide-input-voltage-range applications. However, when the input voltage is close to the output voltage, the NIBB needs to operate in the buck-boost mode, causing a significant efficiency reduction since all four switches operates in the PWM mode. Considering both the current stress limitation and the efficiency optimization, a novel design methodology for the optimal phase-shift modulation of a NIBB in the buck-boost mode is proposed in this paper. Since the four switches in the NIBB form two bridges, the shifted phase between the two bridges can serve as an extra degree of freedom for performance optimization. With general phase-shift modulation, the analytic current expressions for every duty ratio, shifted phase and input voltage are derived. Then with the two key factors in the NIBB, the converter efficiency and the switch current stress, taken into account, an objective function with constraints is derived. By optimizing the derived objective function over the full input voltage range, an offline design methodology for the optimal modulation scheme is proposed for efficiency optimization on the premise of current stress limitation. Finally, the designed optimal modulation scheme is implemented on a DSPs and the design methodology is verified with experimental results on a 300V-1.5kW NIBB prototype.

Pseudo Relaxation-Oscillating 기법의 PWM 발생기를 이용한 저면적, 고효율 SMPS (A Low Area and High Efficiency SMPS with a PWM Generator Based on a Pseudo Relaxation-Oscillating Technique)

  • 임지훈;위재경;송인채
    • 전자공학회논문지
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    • 제50권11호
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    • pp.70-77
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    • 2013
  • 본 논문에서는 새로운 기법의 PWM 발생기를 이용한 저면적, 고효율 SMPS를 제안한다. 제안된 회로에서 PWM의 duty ratio는 pseudo relaxation-oscillation technique를 이용한 PWM 발생기의 내부 커패시터 전압 기울기를 제어하는 방식으로 결정된다. 기존의 SMPS들에 비해, 제안된 제어 방식은 loop bandwidth 보상을 위해 기존의 아날로그 제어방식의 SMPS에서 요구되는 필터회로나 디지털 제어방식의 SMPS에서 요구되는 디지털 compensator가 필요 없기 때문에 단순한 구조로 구성된다. 또한, 제안된 회로는 PWM 발생기의 내부 캐패시터 용량 변화를 통해 1MHz~10MHz까지 스위칭 주파수를 사용자가 선택할 수 있다. 시뮬레이션 수행결과 제안된 SMPS는 10MHz 스위칭 주파수를 선택했을 때 내부회로에서 소모되는 전류는 최대 2.7mA, 파워 Trail을 제외한 전체 시스템의 전류 소모는 15mA였다. 또한, 제안된 SMPS는 시뮬레이션으로 3.3V출력에서 9mV의 최대 리플 전압이 발생하였다. 본 논문에서는 동부하이텍 BCD $0.35{\mu}m$ 공정 파라미터를 이용한 시뮬레이션 및 칩 테스트를 통해 제안된 회로를 검증하였다.

MPPT 제어 기능을 갖는 진동에너지 수확을 위한 CMOS 인터페이스 회로 (A CMOS Interface Circuit for Vibrational Energy Harvesting with MPPT Control)

  • 양민재;윤은정;유종근
    • 전기전자학회논문지
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    • 제20권1호
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    • pp.45-53
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    • 2016
  • 본 논문에서는 진동에너지 수확을 위한 MPPT (Maximum Power Point Tracking) 제어 기능을 갖는 CMOS 인터페이스 회로를 설계하였다. 간단한 구조와 적은 비용으로 출력을 안정화시키기 위해 전력변환기인 DC-DC 부스트 변환기의 출력 단에 PMU (Power Management Unit)를 이용하는 구조를 제안하였다. 또한, 진동소자로부터 최대전력을 수확하여 시스템의 효율을 향상시키기 위해 FOC (Fractional Open Circuit) 방식의 MPPT 제어회로를 설계하였다. 진동소자 (PZT)에서 출력되는 AC 신호는 AC-DC 변환기를 통해 DC 신호로 변환되며, DC-DC 부스트 변환기를 거쳐 승압되고, PMU에 의해 듀티 (duty)를 갖는 안정화된 신호로 변환되어 부하로 공급된다. AC-DC 변환기는 효율 특성이 좋은 능동 다이오드를 이용한 전파정류기를 사용하였으며, DC-DC 부스트 변환기는 제어회로가 간단한 쇼트키 다이오드를 이용한 구조를 사용하였다. 제안된 회로는 $0.35{\mu}m$ CMOS 공정으로 설계되었으며, 설계된 칩의 면적은 $915{\mu}m{\times}895{\mu}m$이다. 설계된 회로의 성능을 검증한 결과 전체회로의 최대 전력효율은 83.4%이다.

Effect of Flashing Light on Oxygen Production Rates in High-Density Algal Cultures

  • Park, Kyong-Hee;Kim, Dong-Il;Lee, Choul-Gyun
    • Journal of Microbiology and Biotechnology
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    • 제10권6호
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    • pp.817-822
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    • 2000
  • A proper flashing light is expected to enhance microalgal biomass productivity and photosynthetic efficiency. The effect of flashing light on high-density Chlorella kessleri (UTEX 398) cultures was studied using light-emitting diodes. A frequency modulator was designed to flash LEDs, and the device successfully provided wide range of frequencies and various duty cycles of flashing. A relatively high frequencies of 10, 20 and 50 kHz were used in this study. These frequencies have very short flashing time ($2-50{\mu}s$), which corresponded to the time constant of the light reaction of photosynthesis. The specific oxygen production rates of photosynthesis under flashing light were compared with those under an equivalent continuous light in specially designed illumination cuvette. The specific oxygen production rates under flashing light were 5-25% higher than those under the continuous light. A range of cell concentration was discovered, where the benefit of flashing light was maximized. The photosynthetic efficiency was also higher under flashing light with frequencies of over 1 kHz, which was a clear indication of flashing light effect and the degree of mutual shading could by overcome by flashing lights, particularly at high-density algal cultures.

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Single Phase Utility Frequency AC-High Frequency AC Matrix Converter Using One-Chip Reverse Blocking IGBTs based Bidirectional Switches

  • Hisayuki, Sugimura;Kwon, Soon-Kurl;Lee, Hyun-Woo;Mutsuo, Nakaoka
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.125-128
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    • 2006
  • This paper presents a novel type soft switching PWM power frequency AC-AC converter using bidirectional active switches or single phase utility frequency AC-high frequency AC matrix converter. This converter can directly convert utility frequency AC (UFAC, 50Hz/60Hz) power to high frequency AC (HFAC) power ranging more than 20kHz up to 100kHz. A novel soft switching PWM prototype of high frequency multi-resonant PWM controlled UFAC-HFAC matrix converter using antiparallel one-chip reverse blocking IGBTs manufactured by IXYS corp. is based on the soft switching resonance with asymmetrical duty cycle PWM strategy. This single phase UFAC-HFAC matrix converter has some remarkable features as electrolytic capacitor DC busline linkless topology, unity power factor correction and sine-wave line current shaping, simple configuration with minimum circuit components, high efficiency and downsizing. This series load resonant UFAC-HFAC matrix converter, incorporating bidirectional active power switches is developed and implemented for high efficiency consumer induction heated food cooking appliances in home uses and business-uses. Its operating performances as soft switching operating ranges and high frequency effective power regulation characteristics are illustrated and discussed on the basis of simulation and experimental results.

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ESM을 통해 본 취업/비취업주부의 소비생활경험 및 주관적 삶의 질 -쇼핑활동을 중심으로- (The Consumption Experiences and Perceived Quality of Life of Korean Housewives through the Experiential Sampling Method-focused on shopping activity)

  • 유현정
    • 한국생활과학회지
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    • 제16권2호
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    • pp.349-365
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    • 2007
  • The purpose of this study was to explore the Korean housewives' consumption experiences and perceived quality of life. Perceived quality of life was composed of four dimensions: motivation, affect, efficiency, and activation. The study results are: 1. Housewives spare their time for physiologic activities(22.9%), household activities(20.1), and personal activities(10.1%) in sequence. 2. Although the motivation that housewives do shopping activities is coming from a sense of duty, the perceived quality of life during shopping is showing far more positive affect than the perceived quality of life during other activities. In this context, shopping activities are interesting in that they are thought of a kind of entertainment as well as work. 3. With an analysis of covariance, housewives' perceived quality of life has an effect on everyday life in that 4 perceived qualities of life such as motivation, affect, efficiency and activation has a significant effect on flow and it has a significant effect on satisfaction.

유도가열용 ZCS PWM SEPP 고주파 인버터의 특성 (Character of Induction Heating ZCS PWM SEPP High Frequency Inverter)

  • 문상필;김칠용;곽동걸;김춘삼
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2007년도 추계학술대회 논문집
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    • pp.133-135
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    • 2007
  • This research presented the new zero-current switching pulse width modulation SEPP(Single Ended Push-Pull)high frequency inverter for solving the problem of the zero-current SEPP high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the zero-current switching pulse width modulation SEPP high frequency inverter. The inverter circuit which is attempted by on-off operation of a switch has the reduction effect of the power loss due to a soft switching and a high frequency switching. And it confirmed that the power regulation is possible continuously from 0.25[kW] until 2.84[kW] in the case the duty rate(D) changes from 0.08 to 0.3 under zero-current switching operating by a dissymmetry pulse width modulating control and the power conversion efficiency comes true the efficiency of 95[%]. Due to the result above, the ZCS PWM SEPP high frequency inverter will be effective as sources of an induction heating apparatus.

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천연가스 개질 방식 중소형 고순도 수소제조 장치 개발 연구 (Study on the development of small-scale hydrogen production unit using steam reforming of natural gas)

  • 서동주;주국택;정운호;박상호;윤왕래
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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    • pp.720-722
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    • 2009
  • This work is mainly focused at developing the hydrogen production unit with the capacity of 20 $Nm^3/h$ of high purity hydrogen. At present steam reforming of natural gas is the preferable method to produce hydrogen at the point of production cost. The developed hydrogen production unit composed of natural gas reformer and pressure swing adsorption system. To improve the thermal efficiency of steam reforming reactor, the internal heat recuperating structure was adopted. The heat contained in reformed gas which comes out of the catalytic beds recovered by reaction feed stream. These features of design reduce the fuel consumption into burner and the heat duty of external heat exchangers, such as feed pre-heater and steam generator. The production rate of natural gas reformer was 41.7 $Nm^3/h$ as a dryreformate basis. The composition of PSA feed gas was $H_2$ 78.26%, $CO_2$ 18.49%, CO 1.43% and $CH_4$ 1.85%. The integrated production unit can produce 21.1 $Nm^3/h$ of high-purity hydrogen (99.997%). The hydrogen production efficiency of the developed unit was more than 58% as an LHV basis.

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새로운 유도가열용 소프트 스위칭 고주파 인버터 (Soft Switching High Frequency Inverter for New Induction Heating)

  • 김칠용;문상필;김영문;김해재;류재엽;김수욱
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
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    • pp.119-124
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    • 2007
  • This research presented the new zero-current switching pulse width modulation SEPP(Single Ended Push-Pull)high frequency inverter for solving the problem of the zero-current SEPP high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the zero-current switching pulse width modulation SEPP high frequency inverter. The inverter circuit which is attempted by on-off operation of a switch has the reduction effect of the power loss due to a soft switching and a high frequency switching. And it confirmed that the power regulation is possible continuously from 0.25[kW] until 2.84[kW] in the case the duty rate(D) changes from 0.08 to 0.3 under zero-current switching operating by a dissymmetry pulse width modulating control and the power conversion efficiency comes true the efficiency of 95[%]. Due to the result above, the ZCS PWM SEPP high frequency inverter will be effective as sources of an induction heating apparatus.

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개선된 효율을 가지는 양방향 Zeta-Flyback 컨버터 (Bidirectional Zeta-Flyback Converter for Improved Efficiency)

  • 정문규;권영안
    • Journal of Advanced Marine Engineering and Technology
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    • 제36권6호
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    • pp.844-849
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    • 2012
  • 양방향 컨버터는 신재생에너지를 이용하는 전력시스템, 무정전 전원 공급장치, 전기차 등 여러분야에서 사용되며, 양방향 절연 컨버터는 양방향 비절연 컨버터보다 높은 신뢰성을 갖지만 효율이 낮다는 단점이 있다. 본 논문에서는 개선된 효율을 가지는 절연된 양방향 Zeta-Flyback 컨버터를 제안한다. 이 컨버터는 양방향 Flyback 컨버터와 양방향 Zeta 컨버터의 중첩으로서 순방향 동작과 역방향 동작에서 전력 흐름이 변압기와 소자를 통해 수행되어 변압기 이용률이 증가하고, 출력 전압은 스위치의 일정 주파수 PWM의 듀티비에 의해 제어된다. 제안된 양방향 Zeta-Flyback 컨버터와 양방향 Flyback 컨버터를 비교하면 제안된 양방향 Zeta-Flyback 컨버터가 더 높은 효율을 갖으며 이를 시뮬레이션과 실험을 통하여 확인하였다.