The Experts below are selected from a list of 32391 Experts worldwide ranked by ideXlab platform

Kyo-beum Lee - One of the best experts on this subject based on the ideXlab platform.

  • A Novel Carrier-Based PWM Method for Vienna Rectifier With a Variable Power Factor
    IEEE Transactions on Industrial Electronics, 2016
    Co-Authors: June-seok Lee, Kyo-beum Lee
    Abstract:

    The Vienna rectifier, which is a nongenerative-boost type rectifier, is used in many applications such as telecommunication systems and wind turbine systems. The Vienna rectifier has a special Operating Requirement. Many switching methods considering this Requirement were proposed. These methods generally take into account the Vienna rectifier's operation with the unity power factor because the Vienna rectifier aims to provide the power to the load. However, as the applications for the Vienna rectifier are diversified, control Requirements have been suggested, including the dc-link voltage balance control and the novel control under severely unbalanced grids. In this paper, we propose a carrier-based pulse-width modulation (CB-PWM) method for Vienna rectifier operation with a variable power factor. The proposed CB-PWM method adds the compensation voltage to the three-phase reference voltages, depending on the power factor, to maintain the sinusoidal input currents of the Vienna rectifier. The performance and effectiveness of the proposed CB-PWM method are verified by simulation and experiment.

June-seok Lee - One of the best experts on this subject based on the ideXlab platform.

  • A Novel Carrier-Based PWM Method for Vienna Rectifier With a Variable Power Factor
    IEEE Transactions on Industrial Electronics, 2016
    Co-Authors: June-seok Lee, Kyo-beum Lee
    Abstract:

    The Vienna rectifier, which is a nongenerative-boost type rectifier, is used in many applications such as telecommunication systems and wind turbine systems. The Vienna rectifier has a special Operating Requirement. Many switching methods considering this Requirement were proposed. These methods generally take into account the Vienna rectifier's operation with the unity power factor because the Vienna rectifier aims to provide the power to the load. However, as the applications for the Vienna rectifier are diversified, control Requirements have been suggested, including the dc-link voltage balance control and the novel control under severely unbalanced grids. In this paper, we propose a carrier-based pulse-width modulation (CB-PWM) method for Vienna rectifier operation with a variable power factor. The proposed CB-PWM method adds the compensation voltage to the three-phase reference voltages, depending on the power factor, to maintain the sinusoidal input currents of the Vienna rectifier. The performance and effectiveness of the proposed CB-PWM method are verified by simulation and experiment.

Huo Mengshen - One of the best experts on this subject based on the ideXlab platform.

  • friction material for brake shoe of heavy axle load wagon and preparation method of friction material
    2014
    Co-Authors: Zhang Xufeng, Zhou Jianhua, Huo Mengshen
    Abstract:

    The invention discloses a friction material for a brake-shoe of a heavy axle-load wagon. The friction material is prepared from the following components in percentage by mass: 6-12 percent of nitrile rubber, 1-4 percent of butadiene styrene rubber, 3-8 percent of A-stage phenolic resin, 0.4-1 percent of insoluble sulfur, 0.1-0.6 percent of an accelerant, 0.1-0.6 part of a curing agent, 2-6 percent of carbon black, 8-18 percent of barite, 1-4 percent of kyanite, 17-40 percent of hybrid fibers, 7-14 percent of magnesium oxide, 2-6 percent of petroleum coke, 2-8 percent of calcium sulfate crystal whiskers, 1-4 percent of molybdenum disulfide, 1-5 percent of crystalline flake graphite, 1-4 percent of artificial graphite, 1-4 percent of mica iron oxide and 1-3 percent of antimony sulfide. The friction material can satisfy the friction performance and mechanical property required by the brake-shoe of the heavy axle-load wagon and can meet the high speed Operating Requirement on heavy load of the wagon.

M M Mahapatra - One of the best experts on this subject based on the ideXlab platform.

  • Effect of Heat Treatment on Microstructure and Hot Impact Toughness of Various Zones of P91 Welded Pipes
    Journal of Materials Engineering and Performance, 2016
    Co-Authors: C. Pandey, M M Mahapatra
    Abstract:

    The new generation super critical thermal power plants are required to operate at enhanced thermal efficiency of over 50% to reduce the fuel consumption and environmental pollution. Creep strength-enhanced ferritic steels, commonly known as Cr-Mo alloys such as P91 (X10CrMoVNb 9-1) are such material of choice for the next generation power plants. The Operating Requirement of these next generation power plants is that steam temperature of around 650 °C is maintained. For such high-temperature application, creep strength of material is the primary consideration together with adequate weld heat-affected zone (HAZ) toughness. Present work deals with the effect of high service temperature on impact toughness of P91 (X10CrMoVNb 9-1) base material, weld fusion zone, and HAZ. The impact toughness of HAZ for conventional weld groove design and narrow weld groove design has been evaluated experimentally in as-welded and at different post-weld heat treatment conditions. Fractography of the impact toughness specimens of base metal, weld fusion zone, and HAZ was carried out using scanning electron microscope. The effects of heat treatment schemes on the percentage of element present at the fracture surface were also studied.

Quan Liang - One of the best experts on this subject based on the ideXlab platform.