Search for dissertations about: "AC Voltage"

Showing result 1 - 5 of 126 swedish dissertations containing the words AC Voltage.

  2. 1. Modeling of Modular Multilevel Converters for Stability Analysis

    Author : Luca Bessegato; Stefan Östlund; Staffan Norrga; Lennart Harnefors; Xiongfei Wang; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Modular multilevel converters MMCs ; stability; admittance; frequency-domain analysis; linearization techniques; current control; voltage control; ac ac converters; railway engineering.; Modulära multinivåomvandlare MMC ; stabilitet; admittans; frekvensanalys; linjäriseringsmetoder; strömreglering; spänningsreglering; ac ac omvandlare; järnvägsteknik.; Electrical Engineering; Elektro- och systemteknik;

    Abstract : Modular multilevel converters (MMCs) have recently become the state-of-the-art solution for various grid-connected applications, such as high-voltage direct current (HVDC) systems and flexible alternating current transmission systems (FACTS). Modularity, scalability, low power losses, and low harmonic distortion are the outstanding properties that make MMCs a key technology for a sustainable future. READ MORE

  4. 2. On impacts and ride-through of voltage sags exposing line-operated AC-machines and metal processes

    Author : Fredrik Carlsson; KTH; []
    Keywords : Rolling mill; Blast furnace; Power Quality; Synchronous machine; Asynchronous machine; Voltage sag; Voltage interruption; Ride-through; Process disturbances; Simulation; Modelling;

    Abstract : During the last decade, power quality has been recognised asa global problem. Among different types of power qualityproblems, voltage sags have been identified to be one of themost severe problems for different process industries. The mostcommon reason to voltage sags is lightning strikes in powerlines. READ MORE

  5. 3. Operation and control of HVDC links embedded in AC systems

    Author : Jenny Paulinder; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; load voltage dependency; system overload; AC DC interaction; HVDC; voltage instability; control of hvdc converters;

    Abstract : .... READ MORE

  6. 4. Power Electronics for Mitigation of Voltage Sags and Improved Control of AC Power Systems

    Author : Marcio Magalhães de Oliveira; KTH; []
    Keywords : power electronics; power quality; voltage sags; voltage-source converters; Custom Power; FACTS; real-time simulations; solid-state devices;

    Abstract : The thesis deals with the application of compensators andswitches based on power electronics in AC transmission anddistribution systems. The objective of the studieddevices/equipment is the power flow and voltage control intransmission systems and the mitigation of voltage sags andmomentary interruptions to critical loads in distributionsystems. READ MORE

  7. 5. Voltage sag ride-through of AC drives : control and analysis

    Author : Kai Pietiläinen; Hans-Peter Nee; Olli Pyrhönen; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electronic measurement and instrumentation; Elektronisk mät- och apparatteknik;

    Abstract : This thesis focuses on controller design and analysis for induction motor (IM) drives, flux control for electrically excited synchronous motors with damper windings (EESMs), and to enhance voltage sag ride-through ability and analysis for a wind turbine application with a full-power grid-connected active rectifier. The goal is to be able to use the existing equipment, without altering the hardware. READ MORE