11 research outputs found

    Single-loop all-pass-filter-based active damping for VSCs with LCL filters connected to the grid

    Get PDF
    LCL filters are commonly used to connect Voltage Sourced Converters (VSCs) to the grid. This type of filters are cheaper than a single inductor, but they can generate resonance problems if no active or passive damping method is used. Active damping methods are becoming popular in the literature because they improve efficiency, but they are sometimes difficult to implement and additional measurements are required. This paper proposes a method to provide active damping for VSCs connected to the grid that is based on making zero the openloop phase at the resonance frequency. It will shown that this strategy provides adequate damping of oscillations and that it can be achieved in two different ways: at the design stage (if the design constraints make it possible) or with an all-pass filter in series with the current controller. All the proposed control algorithms are verified by simulation and in a 15 kW prototype of a three-phase VSC connected to the grid with an LCL filter

    Geodetic Research on Deception Island and its Environment (South Shetland Islands, Bransfield Sea and Antarctic Peninsula) During Spanish Antarctic Campaigns (1987-2007)

    Full text link
    Since 1987, Spain has been continuously developing several scientific projects, mainly based on Earth Sciences, in Geodesy, Geochemistry, Geology or Volcanology. The need of a geodetic reference frame when doing hydrographic and topographic mapping meant the organization of the earlier campaigns with the main goals of updating the existing cartography and of making new maps of the area. During this period of time, new techniques arose in Space Geodesy improving the classical methodology and making possible its applications to other different fields such as tectonic or volcanism. Spanish Antarctic Geodetic activities from the 1987/1988 to 2006/2007 campaigns are described as well as a geodetic and a levelling network are presented. The first network, RGAE, was designed and established to define a reference frame in the region formed by the South Shetlands Islands, the Bransfield Sea and the Antarctic Peninsula whereas the second one, REGID, was planned to control the volcanic activity in Deception Island. Finally, the horizontal and vertical deformation models are described too, as well as the strategy which has been followed when computing an experimental geoid
    corecore