Sökning: "Electrical impedance"

Visar resultat 11 - 15 av 240 avhandlingar innehållade orden Electrical impedance.

  1. 11. Electromagnetic Interference in Distributed Outdoor Electrical Systems, with an Emphasis on Lightning Interaction with Electrified Railway Network

    Författare :Nelson Theethayi; Rajeev Thottappillil; Farhad Rachidi; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Electromagnetic Compatibility EMC ; Lightning; Lightning Protection; Transmission Lines; Electromagnetic Wave Propagation; Underground Cables; Grounding; Electromagnetic Transients; Electromagnetic Interference; Shielding Effectiveness; Railway Systems; Elektroteknik; elektronik och fotonik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : This thesis deals with the electromagnetic compatibility (EMC) problems of distributed electrical networks, especially that caused by lightning to electrified railway. Lightning transients were found to damage important devices that control train movements, causing traffic stoppage and delays. LÄS MER

  3. 12. Fault location in resonant earthed medium voltage distribution systems

    Författare :Md Zakaria Habib; Nathaniel Taylor; Mohamed F. Abdelfattah; Matti Lehtonen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical distribution; Distribution network; Reliability; SAIDI; Fault location; FL; Fault passage indicator; FPI; Compensated neutral; Resonant earthing; Resonant grounding; Petersen coil; Arc suppression coil.; Distributionsnät; Tillförlitlighet; Fellokalisering; FL; Felpassageindikation; FPI; Kompenserat nät; Spoljordat nät; Petersenspole.; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : A major challenge in electric distribution systems is to increase the reliability of the electricity supply in an economical way. At the final medium-voltage level in the system, such as 10 kV or 20 kV, a single feeder may supply tens of medium/low-voltage transformers and hundreds of customers, with many branches of lines and cables where faults can occur. LÄS MER

  4. 13. Electrical Bioimpedance Cerebral Monitoring: Effects of Hypoxia

    Författare :Fernando Seoane Martinez; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Electrical bioimpedance spectroscopy is one way to study the electrical properties of biological matter. Different applications of electrical bioimpedance measurements have already been used in both research and clinical scenarios i.e. impedance plethysmography, total body water contents, etc. LÄS MER

  5. 14. Integrated Transmitters for Cellular User Equipment–Wideband CMOS Power Amplifiers and Antenna Impedance Tuners

    Författare :Jonas Lindstrand; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CMOS; LTE; Impedance tuner; Injection lock; Power amplifier; Efficiency; Polar bandwidth expansion; multiband;

    Sammanfattning : The digital cellular systems era started about thirty years ago with the release of the first digital cellphones. These first digital cellphones were very different from today’s slim and esthetic cellular pocket computers. They were not mass-produced in million units a day, and they were designed for radio performance rather than appearance. LÄS MER

  7. 15. DC-DC Converters - Dynamic Model Design and Experimental Verification

    Författare :Bengt Johansson; Industriell elektroteknik och automation; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; robotics; buck; dc-dc converter; modeling; audio susceptibility; current-mode control; load current; gain scheduling; current transformer; experimental verification; Electronics and Electrical technology; Automation; Elektronik och elektroteknik; Elektroteknik; Electrical engineering; reglerteknik; robotteknik; Automatiska system; control engineering;

    Sammanfattning : To obtain high performance control of a dc-dc converter, a good model of the converter is needed. The load usually affects the dynamics and one way to take this into consideration is to regard the load as a part of the converter. The load is often the most variable part of this system. LÄS MER