Sökning: "Lena Max"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden Lena Max.

1. 1. Design and control of a DC collection grid for a wind farm

   Författare :Lena Max; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; DC collection grid; fault handling; DC DC converter; wind energy; control design; loss evaluation;

   Sammanfattning : In this thesis, the internal DC collection grid for a wind farm is investigated regarding the design, losses and dynamic operation for both normal operating conditions and for different fault conditions. The main advantage for the DC collection grid is the considerably lower weight of the 1 kHz transformers in the DC/DC converters compared to the equivalent 50 Hz transformers. LÄS MER

3. 2. Energy Evaluation for DC/DC Converters in DC-Based Wind Farms

   Författare :Lena Max; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; DC DC converter; loss evaluation; measurements; hard switching converters; wind energy; resonant converters; snubber design;

   Sammanfattning : In this thesis the suitability of three topologies for DC/DC converters in a DC wind farm grid is investigated from an energy efficiency and energy production cost point of view. The three selected topologies are the fullbridge converter, the single active bridge converter and the series parallel resonant converter. LÄS MER

4. 3. Power control strategies for renewable energy systems : The inverter's role in future power systems

   Författare :Sara Anttila; Cecilia Boström; Sandra Eriksson; Lena Max; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Renewable energy systems; Grid-connection; Inverter; Power control; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

   Sammanfattning : Connecting more non-dispatchable renewable energy sources (RESs) will result in a higher power variability and a lower system inertia when the synchronous generators are replaced by inverter-connected RES. Inverter control can be divided in three categories: grid-following, grid-forming (GFM) and grid-supporting. LÄS MER

5. 4. Macroalgae in tropical seascapes : regulating factors and functions in the coastal ecosystem

   Författare :Gustaf Lilliesköld Sjöö; Max Troell; Nils Kautsky; Lena Kautsky; Alina Szmant; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Macroalgae; Coral reefs; Nutrients; Herbivory; Ecological functions; East Africa; Regulating factors; Anthropogenic influence; Seaweed farming; Bioindicator; marin ekotoxikologi; Marine Ecotoxicology;

   Sammanfattning : Although macroalgae usually are inconspicuous on pristine coral reefs, they often thrive on reefs that are subjected to various types of anthropogenic disturbance. This thesis consists of five papers and investigates how biomass and composition of macroalgal communities on coral reefs are affected by regulating factors, such as nutrient availability, herbivory, substrate availability and hydrodynamic forces. LÄS MER

7. 5. I ungdomsrevoltens tid : svensk ungdomsbok och dess mottagande åren kring 1968

   Författare :Lena Kjersén Edman; Umeå universitet; []
   Nyckelord :HUMANIORA; HUMANITIES; criticism; children s books; existentialism; Gunnel Beckman; juvenile books; Max Lundgren; the 1960s;

   Sammanfattning : This dissertation consists of three parts: the fourth chapter in my book Fotboll och frihet«. Studier i Max Lundgrens författarskap (Football and Freedom. Studies in Max Lundgren's Authorship), 1987, and the two studies that this volume contains: En undersökning av tillvaron. LÄS MER