Gotowa bibliografia na temat „High dI/dt”

Abstract High di/dt 4H-silicon carbide (SiC) gate turn-off thyristors (GTOs) are investigated and developed for fast switching-on application. This work has focused on accelerating the turn-on process to improve the di/dt characteristic, and the n-base dopant concentration is carefully designed to increase the injection efficiency of top P+N junction. With reducing n-base dopant concentration from 2.3 × 1017cm−3 to 6.8 × 1016cm−3, the injection efficiency is increased about 18%, and consequently the current rise-up process and subsequent lateral propagation of the anode current are obviously accelerated. Experimental results show that the di/dt capability is greatly improved and a high di/dt of 126 kA cm−2 μs−1 is obtained. The excellent di/dt performance makes the designed 4H-SiC GTO a promising candidate for fast switching-on application.

An enhancement-mode gallium-nitride high-electron-mobility transistor (E-mode GaN HEMT) operated at high frequency is highly prone to current spikes (di/dt) and voltage spikes (dv/dt) in the parasitic inductor of its circuit, resulting in damage to the power switch. To highlight the phenomena of di/dt and dv/dt, this study connected the drain, source, and gate terminals in series with inductors (LD, LS, and LG, respectively). The objective was to explore the effects of di/dt and dv/dt phenomena and operating frequency (fS) on drain-to-source voltage (Vds), drain-to-source current (Ids), and gate-to-source voltage (Vgs). The experimental method comprised two projects: (1) establishment of a measurement system to assess the change of electrical characteristics of the E-mode GaN HEMT and (2) change of the fS and the inductances (i.e., LD, LS, and LG) in the circuit to measure the changes in Vds, Ids, and Vgs, thus summarizing the experimental results. According to the experimental results on electrical characteristics, a gate driver circuit may be designed to drive and protect the E-mode GaN HEMT while being actually applied to a 120-W synchronous buck converter with an output voltage of 12 V and an output current of 10 A.

A coupled-circuit element representation of an IGBT module from Westcode Semiconductors Inc. has been developed, simulated, and experimentally confirmed at TRJUMF in Vancouver, BC. This model can be simulated in PSpice to predict the distribution of current within the IGBT module under high di/dt switching conditions. The goal of the simulations is to determine if the module is an acceptable candidate for implementation in a thyratron replacement switch for high-power pulse-power applications. The model developed has been shown to agree well with frequency domain measurements, and also with finite element method (FEM) simulations and boundary element method (BEM) simulations of the device.
Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate

Power dissipation is becoming a first-order design issue in high-performance microprocessors as clock speeds and transistor densitiescontinue to increase. As power dissipation levels rise, thecooling and reliability of high-performance processors becomesa major issue. This implies that significant research needsto be done in the area of architectural techniques for reducingpower dissipation.One major contributor to a processor's average peak powerdissipation is the presence of high di/dt in its executioncore. High-energy instructions scheduled together in a singlecycle can result in large current spikes during execution. Inthe presence of heavily weighted regions of code, these currentspikes can cause increases in the processor's average peakpower dissipation. However, if the compiler produces largeenough regions, a certain amount of schedule slack should exist,providing opportunities for scheduling optimizations based onper-cycle energy constraints.This thesis proposes a novel approach to instruction schedulingbased on the concept of schedule slack, which builds energyefficient schedules by limiting the energy dissipated in asingle cycle. In this manner, a more uniform di/dt curve isgenerated resulting in a decrease in the execution core's averagepeak power dissipation.

Des impulsions de courant d'amplitude élevée (plusieurs centaines de kA) dans la gamme des microsecondes peuvent être appliquées pour générer des champs magnétiques de l'ordre du mégagauss. Cette technologie relative au domaine des haute puissances pulsées a été utilisée pour des travaux de recherche sur la fusion par confinement inertiel, le X-pinch ou la physique des hautes densités d'énergie. De plus, un certain nombre d'applications industrielles telles que le soudage par impulsion magnétique et la fracturation des roches nécessitent une puissance moyenne élevée, une répétabilité et un générateur d'impulsions de forts courants fiable avec une longue durée de vie. Par conséquent, le développement d'un interrupteur à semi-conducteurs rapide fonctionnant dans la gamme de plusieurs centaines de kA est d'une importance considérable.Un interrupteur rapide à courant élevé est l'un des composants les plus complexes d'un générateur de hautes puissances pulsées. Historiquement, seuls les interrupteurs remplis de gaz pouvaient fonctionner dans de telles conditions extrêmes. Cependant, les interrupteurs remplis de gaz présentent plusieurs inconvénients bien connus, notamment une faible fréquence de répétition des impulsions, une durée de vie courte et une instabilité lors du déclenchement. Ils sont également coûteux à utiliser, nécessitant souvent des systèmes de flux de gaz et des chambres de recirculation de gaz pour une opération répétitive. Ces inconvénients ont freiné l'adoption généralisée des technologies de hautes puissances pulsées.Les récents progrès en physique et technologie des semi-conducteurs ont introduit les interrupteurs à semi-conducteurs dans le domaine des hautes puissances pulsées. En particulier, les structures en silicium à haute tension déclenchées en mode onde d'ionisation par impact représentent une solution prometteuse pour les interrupteurs à semi-conducteurs rapides à très fort courant (dizaines à centaines de kA et gradient de courant de plusieurs dizaines de kA/μs).L'objectif principal de cette thèse est de démontrer expérimentalement la capacité des thyristors à haute tension à commuter rapidement des impulsions de courant d'amplitude élevée. Pour atteindre cet objectif, des études expérimentales et théoriques sont entreprises. Dans les travaux expérimentaux, l'accent principal est porté sur une limitation critique mise en évidence dans la littérature, à savoir la surface de section transversale du thyristor. Pour s'affranchir de cette limitation, plusieurs solutions ont été étudiées dans cette thèse, notamment (i) le déclenchement du plus grand thyristor disponible dans le commerce, d'un diamètre de 100 mm avec une tension de claquage statique de 5,2 kV, (ii) le déclenchement en parallèle d'un ensemble de deux et quatre thyristors à haute tension, (iii) la configuration série-parallèle afin d'augmenter simultanément la tension de blocage et la capacité de courant de l'interrupteur. En termes d'étude théorique, la simulation numérique est réalisée pour apporter une meilleure compréhension des phénomènes de claquage par avalanche en mode de commutation par ionisation d'impact
Micro-second range high-current pulses (100s kA) are applied to generate megagauss-range magnetic fields. This high pulsed power technology has been employed in inertial fusion research, X-pinch, and high-energy-density physics. Moreover, a number of industrial applications such as magnetic pulse welding and rock fracturing require high average power, repeatability, and a reliable high-current pulse generator with a long lifespan. Hence, a fast solid-state switch development operating in the range of several hundred kA is of considerable importance.A fast high-current switch is one of the most complex components in a pulsed power generator. Historically, only gas-filled switches could operate under such extreme conditions. However, gas-filled switches have several well-known disadvantages, including low pulse repetition frequency, short lifetimes, and instability in triggering. They are also expensive to use, often requiring gas flow systems, costly gases, and recirculating chambers of gas for repetitive operation. These disadvantages have hindered the widespread adoption of pulsed power technologies.Recent advancements in semiconductor physics and technology have introduced solid-state switches into the pulsed power domain. In particular, silicon high-voltage structures triggered in impact-ionization wave mode present a promising solution for fast high-current solid-state switches (10s-100s kA and 10s kA/μs).The main goal of this thesis is to experimentally demonstrate the capability of high-voltage thyristors to switch fast-high current pulses. to accomplish this goal, two major axes of study are defined as the experimental and theoretical studies. In the experimental work, the main focus is determined based on a key limitation highlighted in the literature, i.e., the cross-sectional area of the thyristor. To eliminate this limitation several solutions have been investigated in this thesis including (i) triggering the largest commercially available thyristor, 100 mm wafer diameter with 5.2 kV static voltage breakdown. (ii) Parallel triggering of an assembly of two and four high-voltage thyristors. (iii) Series-parallel configuration in order to further increase blocking voltage and current capability of the switch simultaneously. In terms of theoretical study, the numerical simulation is conducted to shed light on the avalanche breakdown phenomena in impact-ionization switching mode

Two cathode design concepts of phase control thyristor (PCT) are compared for 6.5 kV class in the housing with 47mm pole piece (5STP 08F6500). For the same technology curve VT-Qrr, the achievement of different combination of dynamic parameters like commutation turn-off time tq, dV/dt and di/dt capability are discussed. This work expands the know-how on the cathode emitter engineering previously presented for 1.8, 2.8 and 8.5 kV voltage classes.