Search for dissertations about: "hysteresis"

Showing result 6 - 10 of 150 swedish dissertations containing the word hysteresis.

  2. 6. Implementation, identification, and adaptation of Preisach like hysteresis models

    Author : Marcus Hedegärd; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hysteresis modeling; adaptive hysteresis compensation.; generalized Prandtl-Ishlinskii model; Preisach model; magnetoelastic sensor;

    Abstract : The extended generalized Prandtl-Ishlinskii model (XGPI) of hysteresis has a wide applicability, partly because of its capability of modelling highly asymmetric hystereses. For a given parameterization, it is typically identified using non-linear least squares optimization with concomitant problems of convergence, dependence on initial parameter guess and local minima. READ MORE

  4. 7. Exploring Selectivity and Hysteresis : Kinetic Studies on a Potato Epoxide Hydrolase

    Author : Diana Lindberg; Mikael Widersten; Gunnar Johansson; Richard N. Armstrong; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Epoxide hydrolase; regioselectivity; selectivity; hysteresis; conformational changes; cooperativity; deep eutectic solvents; methylstyrene oxide; Biochemistry; Biokemi; Biokemi; Biochemistry;

    Abstract : The kinetic mechanism of an α/β hydrolase fold epoxide hydrolase from potato, StEH1, has been studied with the aims of explaining the underlying causes for enantio- and regioselectivity, both being important for product purity. Further effort has been laid upon understanding the causes of a hysteretic behavior discovered in the measurements leading to Paper I. READ MORE

  5. 8. Electromagnetic Modelling of Power Transformers with DC Magnetization

    Author : Seyed Ali Mousavi; Göran Engdahl; S. V. Kulkarni; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Transformer; Hysteresis; DC magnetization; GICs; FEM; reluctance network method;

    Abstract : DC currents that flow through the ground can be injected to the star windings of power transformers from their grounded neutral points and close their path with transmission lines. The geomagnetically induced currents (GICs) and AC/DC convertors of high voltage direct current (HVDC) systems are the sources of such DC currents. READ MORE

  6. 9. On magnetic amplifiers in aircraft applications

    Author : Lars Austrin; Göran Engdahl; Lars Liljestrand; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; magnetic amplifier magamp ; amorphous; power losses; control winding; self-saturating; hysteresis; converter; more electric aircraft MEA ; inverter; power-by-wire; dymola; permanent magnet generator; PM-generator transformer rectifier unit TRU ; constant speed drive CSD ; excess losses or anomalous losses; modeling; simulation; unmanned aerial vehicle UAV ; Electrical engineering; Elektroteknik;

    Abstract : In the process of designing an electric power supply system for an aircraft, parameters like low weight and low losses are important. Reliability, robustness and low cost are other important factors. READ MORE

  7. 10. Electromagnetic Modelling of Power Transformers for Study and Mitigation of Effects of GICs

    Author : Seyedali Mousavi; Göran Engdahl; Ebrahim Rahimpour; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; transformer; hysteresis; DC magnetization; GMD; GICs; FEM; reluctance network method; low frequency transients; core losses; winding losses; eddy current losses; transformator; hysteresis; DC; likströmsmagnetisering; GMD; GIC; FEM; reluktansnätverksmodell; lågfrekventa transienter; kärnförluster; lindningsförluster; virvelströmsförluster; Electrical Engineering; Elektro- och systemteknik;

    Abstract : Geomagnetic disturbances that result from solar activities can affect technological systems such as power networks. They may cause DC currents in power networks and saturation of the core in power transformers that leads to destruction in the transformer performance. READ MORE