Search for dissertations about: "DC AC converter"
Showing result 1 - 5 of 49 swedish dissertations containing the words DC AC converter.
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1. Enhanced Active Resonant DC Circuit Breakers for HVDC Grids
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
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2. On soft-switching isolated AC/DC converters without auxiliary circuit
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
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3. Design and control of a DC collection grid for a wind farm
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
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4. The control of VSC-HVDC and its use for large industrial power systems
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
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5. Wireless Control of Modular Multilevel Converter Submodules
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