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 16 of 16 for “"Charge Control"”.
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Charge Control of Ionic Polymers
… polymer was associated with the accumulation of charge in the polymer. This thesis will discuss the use of current as a means to better control the accumulation of charge. Better control of the charge will provide more reliable control of the mechanical motion of the polymer. The data presented …
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Charge control in acoustic charge transport devices
Acoustic charge transport (ACT) devices utilize the acoustoelectric effect in a piezoelectric semiconductor, particularly GaAs, to create buried channel charge transfer devices capable of signal processing functions, especially transversal filtering. Charge control in ACT devices concerns the …
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Methods of Aircraft Charge Control During Flight
The accumulation of aircraft electrical charge can impact lightning initiation, cause radio interference, or make it difficult for research aircraft to make accurate measurements of atmospheric electric fields. Two experimental campaigns are described in this thesis that relate to the control of …
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Average current-mode control and charge control for PWM converters
Two control schemes for PWM converters, average current-mode (ACM) control and charge control, are studied in this dissertation. The small-signal models are derived for continuous-conduction mode PWM converters employing these two controls. Sampled-data modeling is applied to the current loop …
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Modeling and optimization of the transistor laser operation
… Lasers (TLs) from two perspectives. First, the charge control model is introduced to provide the electron characteristics in the base of the TLs. The model shows that the quantum wells (QWs) serve as electron traps to reduce the electrical gain and produce an optical gain. Based on the analysis …
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Modeling of the output and transfer characteristics of graphene field-effect transistors
… graphene field-effect transistors by using the charge-control model for the current, based on the solution of the Boltzmann equation in the field-dependent relaxation time approximation. Closed expressions for the conductance, transconductance, and saturation voltage are derived. The results are …
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Two-Dimensional Analysis of Narrow Gate Effects in Micron and Submicron Mosfets (Device Simulation, Modeling)
… of small MOSFETs, are more accurate than simple charge-control analysis. The 2-D numerical model of Ji and Sah demonstrated important design features of the threshold voltage of narrow gate MOSFETs. However, studies of MOSFET characteristics using 2-D numerical analysis, which take into account …
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ESD circuit design and measurement techniques
… the observed transient. A non-quasi-static charge control model is used to accurately simulate both the reverse recovery and forward bias behavior. Part 2 of this thesis reports the design and fabrication of an active feedback based high-voltage tolerant power clamp with optimally biased …
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Advanced technologies for improving high frequency performance of AlGaN/GaN high electron mobility transistors
… include advanced drain delay engineering, charge control in the channel and new N-face GaN HEMTs. Although more work is needed in the future to combine all these new technologies, the initial results are extremely promising.
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Quasi-two-dimensional phenomena at AlGaAs-GaAs heterointerfaces, multiple quantum wells and modulation-doped structures
… quantum wells. In the second section an improved charge control model for \10DFETs is described which predicts some observed experimental phenomena. This model uses boundary conditions obtained from a numerical solution of Schrodinger's and Poisson's equations at an AIGaAs-GaAs heterointerface. …
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A SiC JFET-Based Three-Phase AC PWM Buck Rectifier
… kVA. Additionally, improvements are made to the charge control scheme for the buck rectifier allowing power factor compensation and reduction of input current transients.
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Physical modeling of base carrier lifetime and frequency response of heterojunction bipolar transistor
… the conventional bipolar junction transistor charge control model, this work accounts for the degraded base transfer ratio, which contrasts with the constant base transport factor close to unity in conventional bipolar junction transistor operation, and its variation with the base current. The …
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Dynamics of Spin and Charge of Color Centers in Diamond under Cryogenic Conditions
… multi-color excitation offers deterministic charge state manipulation. While ambient operation has been key to their appeal, bringing NVs to cryogenic conditions opens new opportunities for alternate forms of control schemes and phenomena. This dissertation discusses experimental work and the …
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Derivation of Parabolic Current Control with High Precision, Fast Convergence and Extended Voltage Control Application
Current control is an important topic in modern power electronics system. For voltage source inverters, current control loop ensures the waveform quality at steady state and the fast response at transient state. To improve the current control performance, quite a few nonlinear control strategies …
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Accurate Small-Signal Modeling for Resonant Converters
… approach is demonstrated on the frequency-controlled SRC and LLC converters. The modeling is further extended to, with great accuracy, a charge-controlled LLC converter. In the case of frequency control, a simple third-order equivalent circuit model is provided with high accuracy up to half …
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High-Frequency Quasi-Single-Stage (QSS) Isolated AC-DC and DC-AC Power Conversion
… minimal extra commutation circuitry, simple PWM control, and high efficiency and reliability. A new soft-switched single-phase QSS bi-directional inverter/rectifier (charger) topology is derived based on the QSS power conversion concept. A simple active voltage clamp branch is used to clamp the …