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Showing result 1 - 5 of 141 swedish dissertations matching the above criteria.

  2. 1. Analysis of Synchronous machine dynamics using a novel equivalent circuit model

    Author : Christer Danielsson; Chandur Sadarangani; Göran Engdahl; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Synchronous machine; Equivalent circuit; Magnetic equivalent circuit model; Simulation model; Parameter determination; Electric power engineering; Elkraftteknik;

    Abstract : This thesis investigates simulation of synchronous machines using a novel Magnetic Equivalent Circuit (MEC) model. The proposed model offers sufficient detail richness for design calculations, while still keeping the simulation time acceptably short. Different modeling methods and circuit alternatives are considered. READ MORE

  4. 2. Assessment of safety characteristics for Li-ion battery cells by abuse testing

    Author : Carl Fredrik Larsson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; overcharge; Lithium-ion; toxic gases; abuse test; thermal runaway; short circuit; safety; battery; fire;

    Abstract : Despite the many advantages with lithium-ion batteries there can be disadvantages in form of safetyissues. In an abuse situation a Li-ion cell can undergo a thermal runaway releasing excessive heat,flammable and toxic gas emissions and eventually accompanied by dissembling/explosion and fire. READ MORE

  5. 3. Steady State Operation and Control of Power Distribution Systems in the Presence of Distributed Generation

    Author : Ferry Viawan; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; distance protection; stochastic assessment; voltage dip; line drop compensation; distribution systems; on-load tap changer; overcurrent protection; sensitive equipment; voltage dip immunity; voltage control; short circuit; reactive power control; pilot protection.; protection coordination; protection; Distributed Generation; losses;

    Abstract : In this thesis, the impact of distributed generation (DG) on steady state operation and control of power distribution systems is investigated. Over the last few years, a number of factors have led to an increased interest in DG schemes. DG is gaining more and more attention worldwide as an alternative to large-scale central generating stations. READ MORE

  6. 4. Condition measuring and lifetime modelling of disconnectors, circuit breakers and other electrical power transmission equipment

    Author : Per Westerlund; Patrik Hilber; Tommie Lindquist; William Q Meeker; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reliability; maintenance; condition monitoring; disconnector; circuit breaker; Weibull distribution; prediction; risk analysis; decision making; beta distribution; Electrical Engineering; Elektro- och systemteknik;

    Abstract : The supply of electricity is important in modern society, so the outages of the electric grid should be few and short, especially for the transmission grid. A summary of the history of the Swedish electrical system is presented. The objective is to be able to plan the maintenance better by following the condition of the equipment. READ MORE

  7. 5. On Reliability of SiC Power Devices in Power Electronics

    Author : Diane-Perle Sadik; Hans-Peter Nee; Per Ranstad; Nando Kaminski; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Silicon Carbide; Metal-Oxide-Semiconductor Field-Effect Transistor MOSFET ; Junction Field-Effect Transistor JFET ; Bipolar Junction Transistor BJT ; Reliability; Failure Analysis; Reliability Testing; Short- Circuit Currents; Humidity; Resonant converter; Series-resonant converter SLR ; Base drive circuits; Gate drive circuits; Life-Cycle Cost Analysis LCCA ; Kiselkarbid; MOSFETar; JFETar; Bipolär Junction Transistor BJT ; Tillförlitlighet; Robusthet; Felanalys; Tillförlitlighetstestning; Kortslutningsströmmar; Luftfuktighet; Resonansomvandlare; Serie-resonansomvandlare SLR ; Basdrivkretsar; Gate-drivkretsar; Felskydd; Livscykelkostnadsanalys; Electrical Engineering; Elektro- och systemteknik;

    Abstract : Silicon Carbide (SiC) is a wide-bandgap (WBG) semiconductor materialwhich has several advantages such as higher maximum electric field, lowerON-state resistance, higher switching speeds, and higher maximum allowablejunction operation temperature compared to Silicon (Si). In the 1.2 kV - 1. READ MORE