Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 14 of 14 for “"Current ripples"”.
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Experimental study of current ripples using medium silt
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1982.
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Performance Improvements of Multi-Channel Interleaving Voltage Regulator Modules with Integrated Coupling Inductors
… Although multi-channel interleaving reduces the current ripple stress on the output capacitors, it cannot reduce the current ripples in each channel. The large current ripples reduce the efficiency of the VRM. With the proposed concept of integrated coupling inductors between channels, the …
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Analysis of hunting in Synchronous Hysteresis Motor
… is known as 'hunting'. This problem produces current ripples at the motor's electrical terminals and induces noise on the sensors that monitor gyro activity. This thesis examines the cause of hunting by deriving the motor's torque characteristics from first principles. It also derives a scheme …
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The Modified-Multiphase Boost Converter: Combined Inductors and Capacitors Topology
… already been proven to drastically reduce input current ripple by about 40% in a single-phase implementation. By placing two modified boost converters in parallel with interleaving main switches (multiphase), the input inductors and modified capacitors of the modified topology can be reduced to …
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The influence of current and ripple development on seagrass transplant survival
… the role of hydrodynamic energy from tidal currents in the survival of newly transplanted seagrass, Zostera marina rhizome fragments with living shoots were transplanted into a sediment bed and exposed to unidirectional flow in a flume. In accordance with planting techniques reported to …
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Flow and skin friction over natural rough beds
… here, measured over two-dimensional immobile current ripples, comprises skin-friction time series at four streamwise positions and velocity profiles measured to within a few mm of the bed. The velocity profiles cannot be linked to the local mean skin friction through the law of the wall, so …
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Point of Load converters with coupled inductors for fast transient
… of different inductor configurations to enhance current rise time. Specifically, the study compares common discrete inductors (DL), coupled inductors (CL), notched coupled inductors (NCL), and Trans-Inductor Voltage Regulators (TLVR) in terms of their dynamic response, output voltage ripple, and …
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Flow, sediment transport and bedforms under combined flows
… generated by three pistons. Unidirectional currents were superimposed on these water oscillations using two centrifugal pumps. Fifty-five experiments were conducted in the LOWST, both with and without an initially flattened bed. Bedform development in a 0.25 mm diameter sand bed was studied …
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Modeling and Control of Parallel Three-Phase PWM Converters
… voltage source inverters, buck rectifiers and current source inverters. The averaging of the parallel converters is performed based on a generic functional switching unit, which is called a phase leg in boost rectifiers and voltage source inverters, and a rail arm in buck rectifiers and current …
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Modelling and optimisation of the dynamic performance of a reversible solid oxide fuel cell system for the grid intergration of renewables
… certain grid scenarios due to excess fuel cell current ripples. Simulations show that appropriate DC bus capacitors effectively reduce the ratio of fuel cell current ripple although potential system cost is implied. Finally it is found that the state of charge (SOC) can in fact have a more …
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Multiphase Voltage Regulator Modules with Magnetic Integration to Power Microprocessors
… and winding loss are reduced. The steady-state current ripples can be reduced without compromising the transient responses. The overall efficiency of the converter is improved. The input inductor can also be integrated in the improved integrated magnetic structure. Currently, selecting the …
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Direct Torque Control for Silicon Carbide Motor Drives
… generally required by DTC to reduce the torque ripples and decrease stator current total harmonic distortion (THD), which however can lower the drive efficiency. Through the use of the emerging silicon carbide (SiC) devices, which have lower switching losses compared to their silicon …
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Studies of deep-sea sedimentary microtopography in the North Atlantic Ocean
… 2000 m) have been formed as bed forms of deep currents. These bed forms, all developed in cohesive sediments, include current ripples (spacings of tens of centimeters, formed transverse to the flow), longitudinal triangular ripples (spacings of meters, formed in sandy muds and parallel to the …
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Investigation on Interleaved Boost Converters and Applications
… interleaving impact on the output capacitor current ripple is also studied and summarized in this dissertation. It should be pointed out that interleaving only reduces the total input and output current ripples; the inductor current in each channel still has large ripple if small inductance …