Piezoelectric Transformer Integration Possibility in High Power Density Applications

The contents of this work investigate the capability of integrating the PT in applications by invoking the ratio of the throughput power to volume represented by the term: power density. The fundamentals of the PT are introduced in chapter two. In chapter three, the fundamental limitations of the PT's capability of transferring power to the load are studied. There are three major limitations: temperature rise due to losses during operation, electromechanical limits of material, and interactions with output rectifier. The analysis and estimation are then verified by experiments and calculations implemented on three different PT samples fabricated from three different manufacturers. The subject of chapter four is the behavior of the PT's power amplifier. This chapter concentrates on two main amplifier topologies, optimized based on the simplicity of structure and minimization of components (passive and active): class D and class E amplifiers. The operational characteristics of these amplifiers with the PT are then comparison. Methods to track the optimum frequency and discontinuous working mode of the PT are proposed as the approaches to improve the energy transfer of the PT. In chapter five, prototypes of four devices using a PT are developed and introduced as illustrations of the integration of PTs into practical applications: an igniter for high intensity discharge (HID) lamps, high DC voltage power supplies, and electronic ballasts for LEDs, and stand-alone ionizers for food sterilizers. Some concluding statements and ideas for future works are located in the last chapter - chapter six

Revision of the EU Green Public Procurement Criteria for Street Lighting and Traffic Signals - Preliminary Report

Lighting is used on more than 1.6 million km of roads in EU28 countries, accounting for some 35 TWh of electricity consumption (1.3% of total electricity consumption) and costing public authorities almost €4000 million each year. A broad review of relevant technical, policy, academic and legislative literature has been conducted. This report examines the current market situation and the potential for reducing environmental impacts and electricity costs by assessing the recent developments in road lighting technology, particularly LEDs. Particularly important areas identified relate to energy efficiency, light pollution, product durability and, specifically for longer lasting and rapidly evolving new LED technologies, reparability and upgradeability. The information in this report shall serve as a basis for discussion with stakeholders about the further development and revision of EU GPP criteria for street lighting and traffic signals.JRC.B.5-Circular Economy and Industrial Leadershi

Compact Fluorescent Plug-In Ballast-in-a-Socket

The primary goal of this program was to develop a ballast system for plug-in CFLs (compact fluorescent lamps) that will directly replace standard metal shell, medium base incandescent lampholders (such as Levition No. 6098) for use with portable lamp fixtures, such as floor, table and desk lamps. A secondary goal was to identify a plug-in CFL that is optimized for use with this ballast. This Plug-in CFL Ballastin-a-Socket system will allow fixture manufacturers to easily manufacture CFL-based high-efficacy portable fixtures that provide residential and commercial consumers with attractive, cost-effective, and energy-efficient fixtures for use wherever portable incandescent fixtures are used today. The advantages of this proposed system over existing CFL solutions are that the fixtures can only be used with high-efficacy CFLs, and they will be more attractive and will have lower life-cycle costs than screw-in or adapter-based CFL retrofit solutions. These features should greatly increase the penetration of CFL's into the North American market. Our work has shown that using integrated circuits it is quite feasible to produce a lamp-fixture ballast of a size comparable to the current Edison-screw 3-way incandescent fixtures. As for price points for BIAS-based fixtures, end-users polled by the Lighting Research Institute at RPI indicated that they would pay as much as an additional $10 for a lamp containing such a ballast. The ballast has been optimized to run with a 26 W amalgam triple biax lamp in the base-down position, yet can accept non-amalgam versions of the lamp. With a few part alterations, the ballast can be produced to support 32 W lamps as well. The ballast uses GE's existing L-Comp[1] power topology in the circuit so that the integrated circuit design would be a design that could possibly be used by other CFL and EFL products with minor modifications. This gives added value by reducing cost and size of not only the BIAS, but also possibly other integral CFL and future dimmable integral and plug-in versions of the EFL products

Resonant Behaviour of Pulse Generators for the Efficient Drive of Optical Radiation Sources Based on Dielectric Barrier Discharges

Dielectric barrier discharge (DBD) excimer lamps emit vacuum-UV optical radiation. This work presents novel methods for efficiently operating DBDs with short, high-voltage pulses. Transformer-less systems utilising SiC power semiconductor switches are presented. Pulse frequencies of up to 3.1 MHz and peak inverter efficiencies of 92 % were achieved. The work encloses both mathematical backgrounds of pulsed resonant circuits and practical implementation of low-inductive power stages

Using an LED as a sensor and visible light communication device in a smart illumination system

The need for more efficient illumination systems has led to the proliferation of Solid-State Lighting (SSL) systems, which offer optimized power consumption. SSL systems are comprised of LED devices which are intrinsically fast devices and permit very fast light modulation. This, along with the congestion of the radio frequency spectrum has paved the path for the emergence of Visible Light Communication (VLC) systems. VLC uses free space to convey information by using light modulation. Notwithstanding, as VLC systems proliferate and cost competitiveness ensues, there are two important aspects to be considered. State-of-the-art VLC implementations use power demanding PAs, and thus it is important to investigate if regular, existent Switched-Mode Power Supply (SMPS) circuits can be adapted for VLC use. A 28 W buck regulator was implemented using a off-the-shelf LED Driver integrated circuit, using both series and parallel dimming techniques. Results show that optical clock frequencies up to 500 kHz are achievable without any major modification besides adequate component sizing. The use of an LED as a sensor was investigated, in a short-range, low-data-rate perspective. Results show successful communication in an LED-to-LED configuration, with enhanced range when using LED strings as sensors. Besides, LEDs present spectral selective sensitivity, which makes them good contenders for a multi-colour LED-to-LED system, such as in the use of RGB displays and lamps. Ultimately, the present work shows evidence that LEDs can be used as a dual-purpose device, enabling not only illumination, but also bi-directional data communication

Transients in Power Systems

Power system engineering largely focuses on steady state analysis. The main areas of power system engineering are power flow studies and fault studies - both steady state technologies. But the world is largely transient, and power systems are always subject to time varying and short lived signals. This technical report concerns several important topics in transient analyses of power systems. The leading chapter deals with a new analytical tool-wavelets-for power system transients. Flicker and electric are furnace transients are discussed in Chapters I1 and IV. Chapter 111 deals with transients from shunt capacitor switching. The concluding chapters deal with transformer inrush current and non simultaneous pole closures of circuit breakers. This report was prepared by the students in EE532 at Purdue University. When I first came to Purdue in 1965, Professor El-Abiad was asking for student term projects which were turned into technical reports. I have \u27borrowed\u27 this idea and for many years we have produced technical reports from the power systems courses. The students get practice in writing reports, and the reader is able to get an idea of the coverage of our courses. I think that the students have done a good job on the subject of transients in power systems

Self-oscillating resonant converters: general approach and applications

En aquesta tesi es presenta el funcionament auto-oscil·lant de convertidors ressonants, produït per l'ús apropiat del signe del corrent de l'inductor d'entrada com a mecanisme de canvi de la polaritat de la tensió d'entrada. D'aquesta forma, el corrent d'entrada i el primer harmònic de la tensió d'entrada estan en fase, el que assegura un factor de potència unitari en estat estacionari. Aquest fet confereix una naturalesa de resistor lliure de pèrdues a la descripció del convertidor com biport. Es comprova que aquest mecanisme de generació de l'auto-oscil·lació és efectiu en estructures de segon, tercer i quart ordre. Encara que la creació de l'auto-oscil·lació és una tasca relativament simple, la descripció analítica de la generació del cicle límit associat presenta una elevada complexitat. Aquesta descripció combina l'anàlisi temporal i de freqüència per a justificar que l'espiral generada a partir de condicions inicials nul·les finalment convergeix en una el·lipse. Es demostra l'estabilitat en la generació del cicle límit a partir de l'anàlisi de la recurrència discreta resultant de la consideració de dos creuaments successius per zero del corrent de l'inductor després de completar un cicle d'oscil·lació. Aquest enfocament explica de forma correcta la generació d'espirals bidimensionals i tridimensionals en convertidors de segon i tercer ordre respectivament. Els convertidors ressonants auto-oscil·lants obtinguts mitjançant l'aplicació del mecanisme de commutació previ són sensibles a les pertorbacions de la tensió d'entrada o als canvis de càrrega, pel que és necessari introduir un llaç de regulació de tensió. Aquest fet requereix el modelat previ de la dinàmica del convertidor, que parteix d'una llei de commutació basada en la combinació lineal del corrent de l'inductor i la tensió del condensador. Relacionar les variacions de la constant associada a aquesta combinació lineal amb els canvis de la freqüència de commutació és un aspecte clau del modelat, el qual es duu a terme per a convertidors de segon ordre. El llaç de control resultant mostra un gran ample de banda i una major robustesa que els controladors convencionals.En esta tesis se presenta el funcionamiento auto-oscilante de convertidores resonantes, producido por el uso apropiado del signo de la corriente del inductor de entrada como mecanismo de cambio de la polaridad de la tensión de entrada. De esta forma, la corriente de entrada y el primer armónico de la tensión de entrada están en fase, lo que asegura un factor de potencia unitario en estado estacionario. Este hecho confiere una naturaleza de resistor libre de pérdidas a la descripción del convertidor como bipuerto. Se comprueba que este mecanismo de generación de la auto-oscilación es efectivo en estructuras de segundo, tercer y cuarto orden. Aunque la creación de la auto-oscilación es una tarea relativamente simple, la descripción analítica de la generación del ciclo límite asociado presenta una elevada complejidad. Esta descripción combina análisis temporal y de frecuencia para justificar que la espiral generada a partir de condiciones iniciales nulas finalmente converge en una elipse. Se demuestra la estabilidad en la generación del ciclo límite a partir del análisis de la recurrencia discreta resultante de la consideración de dos cruces sucesivos por cero de la corriente del inductor después de completar un ciclo de oscilación. Este enfoque explica de forma correcta la generación de espirales bidimensionales y tridimensionales en convertidores de segundo y tercer orden respectivamente. Los convertidores resonantes auto-oscilantes obtenidos mediante la aplicación del mecanismo de conmutación previo son sensibles a las perturbaciones de la tensión de entrada o a los cambios de carga, por lo que es necesario introducir un lazo de regulación de tensión. Ello requiere el modelado previo de la dinámica del convertidor, que parte de una ley de conmutación basada en la combinación lineal de la corriente del inductor y la tensión del condensador. Relacionar las variaciones de la constante asociada a esta combinación lineal con los cambios de la frecuencia de conmutación es un aspecto clave del modelado, el cual se lleva a cabo para convertidores de segundo orden. El lazo de control resultante exhibe un amplio ancho de banda y una mayor robustez que los controladores convencionales.In this thesis, self-oscillation in resonant converters is generated by the appropriate use of the input inductor current zero-crossings to change the polarity of the input voltage. As a result, the input current and the first harmonic of the input voltage are in phase, which ensures a unity power factor to the steady-state operation of the resonant converter. This fact confers a nature of loss-free resistor (LFR) on the two-port description of the converter. The self-oscillation generating mechanism is proven to be effective in second, third and fourth order structures. Although the self-oscillation generation is a relatively simple task, the analytical description of the generation is more involved. It combines time-domain and frequency-domain analyses to justify that a spiral starting from zero initial conditions eventually converges into an ellipse that corresponds to the steady-state behavior of the limit cycle. The stability of the generation is demonstrated by proving the stability of the resulting discrete recurrence considering two successive zero-crossings of the input inductor current after completing a generic oscillation cycle. This approach successfully explains the generation of two-dimension and three-dimension spirals in second and third order converters respectively. Self-oscillating resonant converters with the previous mechanism to generate oscillations are a simple procedure to transmit power but they are sensitive to input voltage perturbations or load changes. Hence, a voltage regulation loop has to be added. Inserting a voltage regulation loop requires modeling the dynamic behavior of the self-oscillating resonant converter whose switching law is a linear combination of inductor current and capacitor voltage. Relating the variations of the constant of that linear combination to the changes of the switching frequency is the key aspect of the modeling, which is carried out for second order converters. The resulting closed-loop regulation exhibits larger bandwidth and a better robustness degree than conventional controllers

Modelling RF sheath dynamics for fusion applications

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