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 20 of 49 for “"current injection"”.
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Investigation of the hazards of substrate current injection: transient external latchup and substrate noise coupling
Substrate current injection is the origin of external latchup and substrate noise coupling. The trigger current for external latchup depends on the duration of the trigger event. A physics-based model is provided to model the effects of aggressor to victim spacing and orientation on transient …
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Coherent laser arrays from bottom-surface vertical-cavity surface-emitting lasers
… lasers. By designing a VCSEL array for uniform current injection and having the output coupler on the substrate side of the laser cavity, the laser will more easily operate in the fundamental Gaussian mode. This type of laser is referred to as a bottom-emitting VCSEL. Bottom-emitting VCSELs show …
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Optimal capacitor placement to minimise harmonics in power systems and software tools
… method, the Newton-Raphson method and the current injection method. In addition various freely and commercially available software packages for the harmonic analysis of power systems are studied and compared. For this purpose a questionnaire was sent out to software developers and …
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AC/DC power system small-signal impedance measurement for stability analysis
… However, for ac systems, the traditional current-injection techniques are not suitable, especially for the high power systems. The first contribution of this work is the unique process of injecting a line-to-line current between two phases of a three-phase ac system for the purpose of …
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Development of a power conditioner for a PMSG-based wind energy system integrated into a weak grid
… asymmetrical loads draw distorted unbalanced currents and voltages at the point of common coupling (PCC) which propagate into the distribution network. Power quality has therefore become an important issue, which has resulted in the development of numerous control strategies and other …
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POWER CONDITIONING UNIT FOR SMALL SCALE HYBRID PV-WIND GENERATION SYSTEM
… for the wind generator is based on the current and voltage measured on the dc side of the rectifier connected to the permanent magnet synchronous generator (PMSG). Maximum power point tracking (MPPT) control is provided in normal operation under the rated speed using a dc/dc boost …
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Advanced High-Frequency Electronic Ballasting Techniques for Gas Discharge Lamps
… rectifying circuit is used. To suppress harmonic currents and improve power factor, input-current-shaping (ICS) or power-factor-correction (PFC) techniques are necessary. This dissertation addresses advanced high-frequency electronic ballasting techniques by using a single-stage PFC approach. The …
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Development of a practical electrical tomography system for flexible contact sensing applications
… a custom printed circuit board for managing both current injection and data collection. We show that current injection and voltage measurement protocols respond differently to different positions of the input contact region of interest, consequently affecting the overall performance of the …
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Protection Against Ungrounded Single Phase Open Circuit Faults in 3-Phase Distribution Transformers
… detection and protection method using neutral current injection (as proposed in industry literature) is built and demonstrated.</p> <p>Electric utility operating experience has demonstrated that all too often, loads on 3-phase distribution transformers are not adequately protected against an …
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Evanescently Coupled Vertical Cavity Laser Arrays
… is tunable with changes in the differential current injection between lasers. This work uses antenna array theory and coherence theory to discover that coherence is maximized around purely in-phase and out-of-phase operation conditions. Additionally, this work studies the modes of PhC VCSELs …
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Identification of small-signal dq impedances of power electronics converters via single-phase wide-bandwidth injection
… measurement procedure. Several wide bandwidth injection signals, among which are chirp, multi-tone, pulse and white noise, are compared and theoretically analyzed. Several hardware examples are included in the analysis. The second part of the dissertation will focus on the modeling of …
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Optimum Control for Minimization of Torque Ripple in Synchronous Reluctance Machines
… the machine, magnet flux density distribution, current harmonics and non-idealities in position and current sensors. Harmonic orders and magnitudes of torque ripple developed due to various sources are analyzed. A new control strategy considering saturation is proposed for Synchronous Reluctance …
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In-situ impedance characterization for assessing SiC MOSFETs reliability
… involves injecting a pre-adjusted high-frequency current (≥ 2 MHz) into the device and isolating the resulting voltage component induced by this injection. By applying algebraic operations, the drain-to-source impedance is characterized and separated into its sub-components: on-state resistance …
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"Some properties of silicon p-""i""-n diodes compensated with gold"
… silicon p--""i""-n diodes at low and moderate current injection levels are examined in this work. The forward J-V characteristic of these diodes follows Ohm's law at the lowest injection levels. At slightly higher levels the current density in many cases is very nearly proportional to the cube …
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Studies of magnetic vortices in superconductor networks and clusters by scanning SQUID microscopy
… Dynamics of vortices in large arrays by current injection have also been investigated. As the array is current biased, most vortices are pinned to the grids with a few vortices hopping perpendicular to the direction of current due to the Lorentz force. Some vortices move in parallel and …
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Cortical Pyramidal Neuron Subtype Classification and Visual Response Diversity
… passive neuronal properties and responses to current injection using whole-cell patch-clamp recordings. A blind clustering algorithm exercised on the data revealed the presence of two principle classes of neurons.To address functional profiles, we recorded visual responses of identified …
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EXPERIMENTAL STUDIES OF QUANTUM OSCILLATIONS IN THE TRANSVERSE MAGNETORESISTANCE OF SINGLE-CRYSTALLINE, ULTRAPURE MAGNESIUM: NON-OHMIC EFFECTS.
… field, 'H, is parallel to [0001] and the current density, 'J, lies in the basal plane. In order to study this new phenomenon systematically, we had to overcome two experimental problems. The first was the design of an experimental probe which could reproducibly control, at low …
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Simulating the Modulation Response of Vertical -Cavity Surface -Emitting Lasers
… can be significantly reduced by restricting the current injection area to the area of large transverse optical field. This is achievable by using tapered oxides to make the electrical aperture smaller than the optical aperture. Third, an additional energy balance equation has been added to …
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Photonic crystal emitters in heterogeneously bonded membranes
… operate continuous wave (CW) under electrical injection at room temperature and be manufactured by reproducible methods. To date, no PhC membrane design has met all of these criteria. In this dissertation, a novel PhC membrane device that combines heterogeneous bonding and lateral current …
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