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

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Integrated Operation of Power Conversion Module for DC Distribution System (직류 배전 시스템을 위한 전력 변환 모듈의 통합 운전)

  • Lee, Hee-Jun;Shin, Soo-Choel;Hong, Suk-Jin;Won, Chung-Yuen
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.3
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    • pp.240-248
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    • 2014
  • It is DC power that Output of renewable energy being recently developed and researched. Also, demand of DC power will expect to proliferate due to increase of digital load. Thus, DC distribution system providing high quality of power and reliability has emerged as a new distribution system. If the conventional distribution systems are substituted by proposed DC distribution system, the output of renewable energy can be connected with distribution systems under minimum power conversion. Therefore, in the event of connection with DC load, it can construct an efficient distribution system. In this paper, the integrated parallel operation of power conversion module for DC distribution system is proposed. Also, this paper proposed modularization of power conversion devices for DC distribution system and power control for parallel operation of large capacity system. DC distribution system consists of three power conversion modules such as AC/DC power conversion module 2 set, ESS module 1 set. DC distribution system controls suitable operation depending on the status of the DC power distribution system and load. Integrated operation of these systems is verified by simulation and experiment results.

High-Efficiency DC-DC Converter with Improved Dynamic Response Characteristics for Modular Photovoltaic Power Conversion (모듈형 태양광 발전을 위한 개선된 동적응답 특성을 지닌 고효율 DC-DC 컨버터)

  • Choi, Jae-Yeon;Choi, Woo-Young
    • The Transactions of the Korean Institute of Power Electronics
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    • v.18 no.1
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    • pp.54-62
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    • 2013
  • This paper proposes a high-efficiency DC-DC converter with improved dynamic response characteristics for modular photovoltaic power conversion. High power efficiency is achieved by reducing switching power losses of the DC-DC converter. The voltage stress of power switches is reduced at primary side. Zero-current switching of output diodes is achieved at secondary side. A modified proportional and integral controller is suggested to improve the dynamic responses of the DC-DC converter. The performance of the proposed converter is verified based on a 200 [W] modular power conversion system including the grid-tied DC-AC inverter. The proposed DC-DC converter achieves the efficiency of 97.9 % at 60 [V] input voltage for a 200 [W] output power. The overall system including DC-DC converter and DC-AC inverter achieves the efficiency of 93.0 % when 200 [W] power is supplied into the grid.

Comparative Study on 220V AC Feed System and 300V DC Feed System for Internet Data Centers

  • Kim, Hyo-Sung
    • Journal of Power Electronics
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    • v.12 no.1
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    • pp.157-163
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    • 2012
  • Internet Data Centers (IDCs), which are essential facilities in the modern IT industry, typically have scores of MW of concentrated electric loads. The provision of an Uninterruptible Power Supply (UPS) is necessary for the power feed system of IDCs owing to the need for stable power. Thus, conventional IDC AC power feed systems have three cascaded power conversion stages, (AC-DC), (DC-AC), and (AC-DC), resulting in a very low conversion efficiency. In comparison, DC power feed systems require only a single power conversion stage (AC-DC) to supply AC main power to DC server loads, resulting in comparatively high conversion efficiency and reliability [4-11]. This paper compares the efficiencies of a 220V AC power feed system with those of a 300V DC power feed system under equal load conditions, as established by the Mok-Dong IDC of Korea Telecom Co. Ltd. (KT). Experimental results show that the total operation efficiency of the 300V DC power feed system is approximately 15% higher than that of the 220V AC power feed system.

A New Three Winding Coupled Inductor-Assisted High Frequency Boost Chopper Type DC-DC Power Converter with a High Voltage Conversion Ratio

  • Ahmed Tarek;Nagai Shinichiro;Hiraki Eiji;Nakaoka Mutsuo
    • Journal of Power Electronics
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    • v.5 no.2
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    • pp.99-103
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    • 2005
  • In this paper, a novel circuit topology of a three-winding coupling inductor-assisting a high-frequency PWM boost chopper type DC-DC power converter with a high boost voltage conversion ratio and low switch voltage stress is proposed for the new energy interfaced DC power conditioner in solar photovoltaic and fuel cell generation systems. The operating principle in a steady state is described by using its equivalent circuits under the practical condition of energy processing of a lossless capacitive snubber. The newly-proposed power MOSFET boost chopper type DC-DC power converter with the three-winding coupled inductor type transformer and a single lossless capacitor snubber is built and tested for an output power of 500W. Utilizing the lower voltage and internal resistance power MOSFET switch in the proposed PWM boost chopper type DC-DC power converter can reduce the conduction losses of the active power switch compared to the conventional model. Therefore, the total actual power conversion efficiency under a condition of the nominal rated output power is estimated to be 81.1 %, which is 3.7% higher than the conventional PWM boost chopper DC power conversion circuit topology.

Comparison of Conventional DC-DC Converter and a Family of Diode-Assisted DC-DC Converter in Renewable Energy Applications

  • Zhang, Yan;Liu, Jinjun;Ma, Xiaolong;Feng, Junjie
    • Journal of Power Electronics
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    • v.14 no.2
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    • pp.203-216
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    • 2014
  • In the conventional dc-dc converter, a pair of additional diode and the adjacent passive component capacitor/inductor can be added to the circuit with an X-shape connection, which generates a family of new topologies. The novel circuits, also called diode-assisted dc-dc converter, enhance the voltage boost/buck capability and have a great potential for high step-up/step-down power conversions. This paper mainly investigates and compares conventional dc-dc converter and diode-assisted dc-dc converter in wide range power conversion from the aspects of silicon devices, passive components requirements, electro-magnetic interference (EMI) and efficiency. Then, a comprehensive comparison example of a high step-up power conversion system was carried out. The two kinds of boost dc-dc converters operate under the same operation conditions. Mathematical analysis and experiment results verify that diode-assisted dc-dc converters are very promising for simultaneous high efficiency and high step-up/step-down power conversion in distributed power supply systems.

Study on conversion efficiency of RF-DC converter with series diode (직렬 연결 RF-DC 변환기의 변환효율에 관한 연구)

  • Choi, Ki-Ju;Hwang, Hee Yong
    • Journal of Industrial Technology
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    • v.30 no.A
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    • pp.69-73
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    • 2010
  • In this paper, we designed the RF-DC converter used in wireless power transmission system and studied how to design the RF-DC converter of high conversion efficiency. The RF-DC converter operate at 2.45GHz and the diode is connected with series. The RF-DC converter uses shorted stub for DC loop and matching. We can divide the RF-DC converter circuit into four blocks. The reflection coefficients between the blocks were optimized for the maximum conversion efficiency at 0 dBm input power and $1300{\Omega}$ load impedance. The final design of the RF-DC converter has a 52 percent conversion efficiency.

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Transformerless Three-Level DC-DC Buck Converter with a High Step-Down Conversion Ratio

  • Zhang, Yun;Sun, Xing-Tao;Wang, Yi-Feng;Shao, Hong-Jun
    • Journal of Power Electronics
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    • v.13 no.1
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    • pp.70-76
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    • 2013
  • For high power high step-down dc-dc conversion applications, conventional three-level dc-dc converters are subject to extreme duty cycles or increased volume and cost due to the use of transformers. In this paper, a transformerless three-level dc-dc buck converter with a high step-down conversion ratio is proposed. The converter comprises two asymmetrical half bridges, which are of the neutral point clamped structures. Therefore, the output pulse voltage of the converter can be obtained in terms of the voltage difference between the two half bridges. In order to realize harmonious switching of the converter, a modulation strategy with capacitor voltages self balance is presented. According to the deduced output dc voltage function, transformerless operation without extreme duty cycles can be implemented. Experimental results from a 1kW prototype verify the validity of the proposed converter. It is suitable for ship electric power distribution systems.

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.902-904
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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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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.1820-1822
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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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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.V.
    • Proceedings of the KIEE Conference
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    • pp.3114-3116
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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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