Search for dissertations about: "converter AC DC"

Showing result 1 - 5 of 49 swedish dissertations containing the words converter AC DC.

2. 1. Enhanced Active Resonant DC Circuit Breakers for HVDC Grids

   Author : Tim Augustin; Hans-Peter Nee; Marley Becerra; Jürgen Biela; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Active damping; Actuator; DC circuit breakers; DC grid; DC power systems; Fast mechanical switch; Fault handling strategy; Gas discharge devices; HVDC; HVDC circuit breakers; Multilevel converters; Multiterminal HVDC; Power transmission; Spark gaps; Thomson-coil actuator; Vacuum interrupter; Voltage Source Converter VSC ; Electrical Engineering; Elektro- och systemteknik;

   Abstract : High-voltage DC (HVDC) grids are considered promising for the electricity grid expansion required to integrate renewable energy sources into the existing infrastructure. DC fault currents increase rapidly and lack a current zero crossing. READ MORE

4. 2. On soft-switching isolated AC/DC converters without auxiliary circuit

   Author : Staffan Norrga; Stefan Östlund; Rik De Doncker; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical power technology; voltage source converter; cycloconverter; isolated converter; medium frequency transformer; soft switching; modulation; commutation; wind power; electric traction; Elkraftteknik; Electric power engineering; Elkraftteknik;

   Abstract : The thesis is concerned with a class of power electronic converter systems that permit bidirectional AC/DC conversion with galvanic separation of the AC and DC sides by a transformer operating at elevated frequency. The systems consist of a capacitively snubbered voltage source converter and a cycloconverter, separated by the mentioned transformer. READ MORE

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

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

   Abstract : 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. READ MORE

6. 4. 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. 5. Wireless Control of Modular Multilevel Converter Submodules

   Author : Baris Ciftci; Hans-Peter Nee; Lennart Harnefors; Staffan Norrga; James Gross; Lars Kildehöj Rasmussen; Remus Teodorescu; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 5G mobile communication; autonomous control; converter control; distributed control; electromagnetic interference; emerging technology; fault ride-through; modular multilevel converter MMC ; prototype; wireless control; Electrical Engineering; Elektro- och systemteknik;

   Abstract : The modular multilevel converter (MMC) has extensively been used in high-voltage, high-power applications such as high-voltage dc transmission systems and flexible alternating current transmission systems. The control of MMC submodules is conventionally realized using wired communication systems. READ MORE