Search for dissertations about: "DC power systems"

Showing result 11 - 15 of 139 swedish dissertations containing the words DC power systems.

2. 11. Modeling of losses in power transformers from dc to the low kilohertz range

   Author : Julius Krah; Göran Engdahl; Roland Eriksson; Anthony Moses; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical power technology; power transformer; losses; magnetic hysteresis; magnetic measurement systems; medium frequency; eddy currents; skin effect; thermal diffusion; Elkraftteknik; Electric power engineering; Elkraftteknik;

   Abstract : The development of HVDC converters, local generation and tractions systems increases the demand for power converters. While a lot of studies have been conducted on the power electronics, there are still open questions concerning the contained power transformer that operates at a few kilohertz. READ MORE

4. 12. DC Distributed Power Systems - Analysis, Design and Control for a Renewable Energy System

   Author : Per Karlsson; Industriell elektroteknik och automation; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Energiforskning; fault detection; load sharing; wind power; DC distributed power system; voltage control; Energy research; Elektronik och elektroteknik; VSC; Electronics and Electrical technology;

   Abstract : Renewable energy systems are likely to become wide spread in the future due to environmental demands. As a consequence of the dispersed nature of renewable energy systems, this implies that there will be a distributed generation of electric power. READ MORE

5. 13. Dynamic Analysis of Harmonics in Electrical Systems

   Author : Erik Möllerstedt; Institutionen för reglerteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Automation; converter control; modeling; linear time periodic systems; frequency domain analysis; harmonics; power systems; small signal stability; robotics; control engineering; Automatiska system; robotteknik; reglerteknik;

   Abstract : Frequency domain analysis and design of power systems is complicated in the presence of harmonics, switching dynamics, nonlinearities, unbalances, and for systems with mixed ac/dc dynamics. The reason is that linearization of the system does not lead to a time invariant system, but a system with periodically time varying dynamics, which implies that there is coupling between different frequencies. READ MORE

6. 14. The control of VSC-HVDC and its use for large industrial power systems

   Author : Cuiqing Du; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; VSC-HVDC; inner current controller; outer controller; PWM; dc dc converter; voltage dips; dc networks;

   Abstract : With the recent developments in semiconductors and control equipment, Voltage Source Converter based High Voltage direct Current (VSC-HVDC) has become feasible. Due to the use of VSC technology and Pulse Width Modulation (PWM), it has a number of potential advantages: short circuit current reduction; rapid, independent control of the active and reactive power, etc. READ MORE

7. 15. 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