• Title, Summary, Keyword: DC-DC power conversion

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Characteristics of DC 48[V] telecommunication power supply (DC 48[V] 통신용 전원 장치의 특성)

  • Jung, H.T.;Jo, M.C.;Youn, Y.T.;Kim, J.Y.;Mun, S.P.;Suh, K.Y.
    • Proceedings of the KIEE Conference
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    • pp.2462-2464
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    • 2005
  • The AC-DC converter, which has three-phase AC power as input and isolated DC power as output is used for the regulated DC power supply of the telecommunication power processing system for several kilowatt class applications. The conventional DC power supply for the telecommunication power system comprises a PWM rectifier with sine-wave shaping input current unity power factor and a DC/DC converter connected to the PWM converter, which obtains DC 48[V]. Since power passes through these two power stage converters, the conversion power loss is difficult to provide high efficiency. To resolve these problems, this paper presents a new PWM rectified as a 1-stage power conversion method. It simulation and experimental results as proved from a Practical point of view that 92.1[%]of conversion efficiency and input current which can meet harmonics regulation of the Class-A in IEC61000-3-3 are achieved.

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Comparative Study on AC and DC Feed System for Internet Data Center (인터넷데이터센터의 교류, 직류급전시스템 비교 분석)

  • Kim, Du-Hwan;Kim, Hyo-Sung
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.1
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    • pp.27-33
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    • 2012
  • Internet Data Centers (IDC), as essential facilities for modern IT industry, typically have scores of MW of concentrated electric loads. Uninterruptible Power Supplies (UPS) are necessary for the power feed system of IDCs because of stable power requirement. Thus, conventional AC power feed systems of IDCs have three cascaded power conversion stages such as (AC-DC), (DC-AC), and (AC-DC), which results in very low conversion efficiency. On the contrary, DC power feed systems need just a single power conversion stage (AC-DC) supplying AC mains power to DC server loads, which gives comparatively high conversion efficiency and reliability. This paper compares the efficiencies between 220V AC power feed system and 300V DC power feed system on equal load conditions which were established in Mok-Dong IDC of Korea Telecom company (KT). Experimental results show that the total operation efficiency of the 300V DC power feed system is around 15% higher than that of the 220V AC power feed system.

Energy Conversion System using a Novel Multi-Mode DC/DC Converter for Hybrid Electric Vehicles (새로운 멀티 모드 DC-DC 컨버터를 이용한 하이브리드 전기자동차용 전력변환 시스템)

  • Park, Tae-Sik
    • The Transactions of the Korean Institute of Power Electronics
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    • v.18 no.2
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    • pp.192-198
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    • 2013
  • The rapidly growing demand for electric power systems in electric vehicles (EVs) and hybrid electric vehicles (HEVs) require simpler, cost-effective, and higher performance components. In this paper, a novel power conversion system for hybrid electric vehicles is proposed for these needs. The proposed power conversion system reduces the conversion system cost while preserving same functionality. The proposed power conversion system can boost multi-sources to drive a traction motor and to store energy at the same time reducing number of switching components. In this paper, all operational modes of the proposed converter are explained in detail and verified by a computer simulation first. Then, the topology and operational modes are experimentally verified. Based on the results, the feasibility of the proposed multi-mode single leg power conversion system for EV and HEV applications is discussed.

Design and Control of Novel Topology for Photovoltaic DC/DC Converter with High Efficiency under Wide Load Ranges

  • Lee, Jong-Pil;Min, Byung-Duk;Kim, Tae-Jin;Yoo, Dong-Wook;Yoo, Ji-Yoon
    • Journal of Power Electronics
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    • v.9 no.2
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    • pp.300-307
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    • 2009
  • In this paper, design and control is proposed for a four input-series-output-series-connected ZVS full bridge converter for the photovoltaic power conditioning system (PCS). The novel topology for a photovoltaic (PV) DC/DC converter that can dramatically reduce the power rating and increase the efficiency of a PV system by analyzing PV module characteristics is proposed. The control scheme, including an input voltage controller is proposed to achieve equal sharing of the input voltage as well output voltages by a four series connected module. Design methods for ZVS power stage are also introduced. The total PV system is implemented for a 250-kW PV power conditioning system (PCS). This system has only three DC/DC converters with a 25-kW power rating and uses only one-third of the total PV PCS power. The 25-kW prototype PV DC/DC converter is introduced to verify experimentally the proposed topology. In addition, an experimental result shows that the proposed topology exhibits good performance.

A Comparative Study of Simple Ac-Dc PWM Full-Bridge Current-Fed and Voltage-Fed Converters

  • Moschopoulos Gerry;Shah Jayesh
    • Journal of Power Electronics
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    • v.4 no.4
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    • pp.246-255
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    • 2004
  • Ac-dc PWM single-stage converters that integrate the PFC and dc-dc conversion functions in a single switching converter have been proposed to try to minimize the cost and complexity associated with implementing two separate and independent switch-mode converters. In this paper, two simple ac-dc single-stage PWM full-bridge converters are considered - one current-fed, the other voltage-fed. The operation of both converters is explained and their properties are noted. Experimental results obtained from simple lab prototypes of both converters are presented, then compared and discussed.

Parallel Operation of DC/DC Converter for Large-scaled PV PCS (대용량 태양광 PCS용 DC/DC 컨버터의 병렬운전)

  • Lee, Jong-Pil;Lee, Kyoung-Jun;Cha, Hon-Yong;Yoo, Dong-Wook;Yoo, Ji-Yoon
    • Proceedings of the KIPE Conference
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    • pp.97-98
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    • 2010
  • 현재 대용량의 태양광 발전에 사용되는 정격용량은 250kW급에 이르고 있는데, 단일 인버터로 구성되어 있지 않고 컨버터를 사용하여 구성하는 경우 단일용량으로 컨버터 250kW급을 구현하는 것은 현실적으로 정격 소자, 수동소자와 시스템의 효율 등의 문제로 인하여 그 구현에 현실적인 한계가 있다. 따라서 규격화 된 용량의 단일 전원장치를 병렬 운전함으로써 이와 같은 문제점을 해결할 수 있다. 본 연구에서는 CAN 통신을 이용하여 250kW PV PCS에 적용한 DC/DC 컨버터 4대의 병렬운전 기법을 제안하고 실험을 통해 그 우수성을 검증한다.

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Single Power-conversion AC-DC Converter with High Power Factor (고역률을 갖는 단일 전력변환 AC-DC 컨버터)

  • Cho, Yong-Won;Park, Chun-Yoon;Kwon, Bong-Hwan
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.1
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    • pp.23-30
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    • 2014
  • This paper proposes a single power-conversion ac-dc converter with a dc-link capacitor-less and high power factor. The proposed converter is derived by integrating a full-bridge diode rectifier and a series-resonant active-clamp dc-dc converter. To obtain a high power factor without a power factor correction circuit, this paper proposes a suitable control algorithm for the proposed converter. The proposed converter provides single power-conversion by using the proposed control algorithm for both power factor correction and output control. Also, the active-clamp circuit clamps the surge voltage of switches and recycles the energy stored in the leakage inductance of the transformer. Moreover, it provides zero-voltage turn-on switching of the switches. Also, a series-resonant circuit of the output-voltage doubler removes the reverse-recovery problem of the output diodes. The proposed converter provides maximum power factor of 0.995 and maximum efficiency of 95.1% at the full-load. The operation principle of the converter is analyzed and verified. Experimental results for a 400W ac-dc converter at a constant switching frequency of 50kHz are obtained to show the performance of the proposed converter.

Polarity Inversion DC/DC Power Conversion Power Supply with High Voltage Step-up Ratio (고전압 변환비치 극성 반전형 DC/DC 전력 변환 전원장치)

  • Jung, Dong-Yeol;Jung, Yong-Joon;Hong, Sung-Soo;Han, Sang-Kyoo;SaKong, Sug-Chin;Roh, Chung-Wook
    • The Transactions of the Korean Institute of Power Electronics
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    • v.13 no.3
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    • pp.196-205
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    • 2008
  • A noble polarity inversion dc/dc power conversion circuit that has the high input-output voltage conversion ration characteristics is presented for high voltage DC power supply applications. The proposed circuit features the reduced voltage stresses of the component compared to those of the conventional ones. The operational principles of the proposed circuit is analyzed and comparative features are presented. The simulation results and experimental results are presented to verify the validity of the proposed circuit.

A New Approach for Constant DC Link Voltage in a Direct Drive Variable Speed Wind Energy Conversion System

  • Jeevajothi, R.;Devaraj, D.
    • Journal of Electrical Engineering and Technology
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    • v.10 no.2
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    • pp.529-538
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    • 2015
  • Due to the high efficiency and compact mechanical structure, direct drive variable speed generators are used for power conversion in wind turbines. The wind energy conversion system (WECS) considered in this paper consists of a permanent magnet synchronous generator (PMSG), uncontrolled rectifier, dc-dc boost converter controlled with maximum power point tracking (MPPT) and adaptive hysteresis controlled voltage source inverter (VSI). For high utilization of the converter's power capability and stabilizing voltage and power flow, constant DC-link voltage is essential. Step and search MPPT algorithm which senses the rectified voltage ($V_{DC}$) alone and controls the same is used to effectively maximize the output power. The adaptive hysteresis band current control is characterized by fast dynamic response and constant switching frequency. With MPPT and adaptive hysteresis band current control in VSI, the DC link voltage is maintained constant under variable wind speeds and transient grid currents respectively.

Wireless Energy Transmission High-Efficiency DC-AC Converter Using High-Gain High-Efficiency Two-Stage Class-E Power Amplifier

  • Choi, Jae-Won;Seo, Chul-Hun
    • Journal of electromagnetic engineering and science
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    • v.11 no.3
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    • pp.161-165
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    • 2011
  • In this paper, a high-efficiency DC-AC converter is used for wireless energy transmission. The DC-AC convertter is implemented by combining the oscillator and power amplifier. Given that the conversion efficiency of a DC-AC converter is strongly affected by the efficiency of the power amplifier, a high-efficiency power amplifier is implemented using a class-E amplifier structure. Also, because of the low output power of the oscillator connected to the input stage of the power amplifier, a high-gain two-stage power amplifier using a drive amplifier is used to realize a high-output power DC-AC converter. The high-efficiency DC-AC converter is realized by connecting the oscillator to the input stage of the high-gain high-efficiency two-stage class-E power amplifier. The output power and the conversion efficiency of the DC-AC converter are 40.83 dBm and 87.32 %, respectively, at an operation frequency of 13.56 MHz.