Modeling and Checking the Power Quality of High Pressure Sodium Vapor Lamp

High pressure sodium Vapor lamps due to long service life High Light, as the most comprehensive street lighting and industrial lighting Whose use is increasing day by day. One of the major drawbacks to these lamps is producing a lot of current harmonic. Therefore, check the Power Quality of these lamps becomes necessary. To check the quality of our lamps, it's necessary to express the exact model of these lamps. In this paper, we simulate a high-pressure lamp based on plasma physics equations. With this exact model, the power consumption of these lamps is considered by using THD and the results are compared with the standard values. In this paper, taking into account the magnetic ballast for a high-pressure sodium Vapor lamp, a precise simulation of these lamps was performed using the MATLAB / Simulink software

Analysis of energy service industry

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1994.Includes bibliographical references (leaves 126-129).by Ichiro Soma.M.S

Electronic operation and control of high-intensity gas-discharge lamps

The ever increasing amount of global energy consumption based on the application of fossil fuels is threatening the earth’s natural resources and environment. Worldwide, grid-based electric lighting consumes 19 % of total global electricity production. For this reason the transition towards energy efficient lighting plays an important environmental role. One of the key technologies in this transition is High-Intensity Discharge (HID) lighting. The technical revolution in gas-discharge lamps has resulted in the highlyefficient lamps that are available nowadays. As with most energy efficient light solutions, all HID lighting systems require a ballast to operate. Traditionally, magnetic ballast designs were the only choice available for HID lighting systems. Today, electronic lampdrivers can offer additional power saving, flicker free operation, and miniaturisation. Electronic lamp operation enables additional degrees of freedom in lamp-current control over the conventional electro-magnetic (EM) ballasts. The lamp-driver system performance depends on both the dynamics of the lamp and the driver. This thesis focuses on the optimisation of electronically operated HID systems, in terms of highly-efficient lamp-driver topologies and, more specifically, lamp-driver interaction control. First, highly-efficient power topologies to operate compact HID lamps on low-frequency-square-wave (LFSW) current are explored. The proposed two-stage electronic lamp-driver consists of a Power Factor Corrector (PFC) stage that meets the power utility standards. This converter is coupled to a stacked buck converter that controls the lamp-current. Both stages are operated in Zero Voltage Switching (ZVS) mode in order to reduce the switching losses. The resulting two-stage lamp-drivers feature flexible controllability, high efficiency, and high power density, and are suitable for power sandwich packaging. Secondly, lamp-driver interaction (LDI) has been studied in the simulation domain and control algorithms have been explored that improve the stability, and enable system optimisation. Two HID lamp models were developed. The first model describes the HID lamp’s small-signal electrical behaviour and its purpose is to aid to study the interaction stability. The second HID lamp model has been developed based on physics equations for the arc column and the electrode behaviour, and is intended for lampdriver simulations and control applications. Verification measurements have shown that the lamp terminal characteristics are present over a wide power and frequency range. Three LDI control algorithms were explored, using the proposed lampmodels. The first control principle optimises the LDI for a broad range of HID lamps operated at normal or reduced power. This approach consists of two control loops integrated into a fuzzy-logic controller that stabilises the lamp-current and optimises the commutation process. The second control problem concerns the application of ultra high performance (UHP) HID lamps in projection applications that typically set stringent requirements on the quality of the light generated by these lamps, and therefore the lampcurrent. These systems are subject to periodic disturbances synchronous with the LFSW commutation period. Iterative learning control (ILC) has been examined. It was experimentally verified that this algorithm compensates for repetitive disturbances. Third, Electronic HID operation also opens the door for continuous HID lamp dimming that can provide additional savings. To enable stable dimming, an observer-based HID lamp controller has been developed. This controller sets a stable minimum dim-level and monitors the gas-discharge throughout lamp life. The HID lamp observer derives physical lamp state signals from the HID arc discharge physics and the related photometric properties. Finally, practical measurements proved the proposed HID lamp observer-based control principle works satisfactorily

Energy saving controller for fluorescent lamps

Although fluorescent lamp is a very efficient lighting device in daily life, still the high harmonic distortion and low power factor cause unnecessary energy consumption. In today’s environment demanding energy efficiency, it is important to reduce this energy loss by integrating an energy saving controller in the electromagnetic ballast of fluorescent lamps. The research presented in this thesis investigates the design and implementation of a new energy saving controller for electromagnetic fluorescent lamp network. The newly developed controller attempts to reduce power losses in both the electromagnetic ballasts and fluorescent lamps by regulating the incoming supply voltage to an optimum level. In addition, the new controller is able to adjust the illuminance level of working environment lightings under either dark or bright condition. Moreover, the function of the new controller is extended with time scheduling control capability, where the switching of lighting systems can be controlled at predetermined times based on occupancy schedule. Both simulation and practical results show that the implemented controller reduces energy consumption by at least 37.5%, by reducing the incoming supply voltage by 15%. In addition, it is desirable to have variable illuminance level control to decrease the energy losses. The experimental results show that the illuminance output level of electromagnetic ballast fluorescent lamps can be decreased by 50% using the new controller while maintaining unity power factor. Integration of the new energy saving controller into electromagnetic ballast fluorescent lamps impressively outperforms the existing electronic dimmable ballast. This new controller brings great ideas for energy saving in the use of fluorescent lamps

Novel Offline Switched Mode Power Supplies for Solid State Lighting Applications

In recent years, high brightness light emitting diodes (HBLEDs) have increasingly attracted the interest of both industrial manufacturers and academic research community. Among the several aspects that make LED technology so attractive, the most appreciated characteristics are related to their robustness, high efficiency, small size, easy dimming capability, long lifetime, very short switch-on/switch-off times and mercury free manufacturing. Even if all such qualities would seem to give to solid state lighting a clear advantage over all the other kinds of competing technologies, the issues deriving from the need of LED technology improvement, on one hand, and of the development of suitable electronic ballasts to properly drive such solid state light sources, on the other, have so far hindered the expected practical applications. The latter problem, in particular, is nowadays considered the main bottleneck in view of a widespread diffusion of solid state technology in the general lighting market, as a suitable replacement of the still dominant solutions, namely halogen and fluorescent lamps. In fact, if it is true that some aspects of the devices’ technology (e.g. temperature dependent performance, light quality, efficiency droop, high price per lumen, etc…) still need further improvements, it is now generally recognized that one of the key requirements, for a large scale spread of solid state lighting, is the optimization of the driver. In particular, the most important specifications for a LED lamp ballast are: high reliability and efficiency, high power factor, output current regulation, dimming capability, low cost and volume minimization (especially in domestic general lighting applications). From this standpoint, the main goal is, therefore, to find out simple switched mode power converter topologies, characterized by reduced component count and low current/voltage stresses, that avoid the use of short lifetime devices like electrolytic capacitors. Moreover, if compactness is a major issue, also soft switching capability becomes mandatory, in order to enable volume minimization of the reactive components by increasing the switching frequency in the range of the hundreds of kHz without significantly affecting converter’s efficiency. It is worth mentioning that, in order to optimize HBLED operation, also other matters, like the lamp thermal management concern, should be properly addressed in order to minimize the stress suffered by the light emitting devices and, consequently, the deterioration of the light quality and of the expected lamp lifetime. However, being this work focused on the issues related to the research of innovative driving solutions, the aforementioned thermal management problems, as also all the topics related to the improvement of solid state devices’ technology, will be left aside. The main goal of the work presented in this thesis is, indeed, to find out, analyze and optimize new suitable topologies, capable of matching the previously described specifications and also of successfully facing the many challenges dictated by the future of general lighting. First of all, a general overview of solid state lighting features, of the state of the art of lighting market and of the main LED driving issues will be provided. After this first introduction, the offline driving concern will be extensively discussed and different ways of approaching the problem, depending on the specific application considered, will be described. The first kind of approach investigated is based on the use of a simple structure relying on a single power conversion stage, capable of concurrently ensuring: compliance with the standards limiting the input current harmonics, regulation of the load current and also galvanic isolation. The constraints deriving from the need to fulfil the EN 61000-3-2 harmonics standard requirements, when using such kind of solution for low power (<15W) LED driving purposes, will be extensively discussed. A low cost, low component count, high switching frequency converter, based on the asymmetrical half bridge flyback topology, has been studied, developed and optimized. The simplicity and high compactness, characterizing this solution, make it a very good option for CFL and bulb replacement applications, in which volume minimization is mandatory in order to reach the goal of placing the whole driving circuitry in the standard E27 sockets. The analysis performed will be presented, together with the design procedure, the simulation outcomes and the different control and optimization techniques that were studied, implemented and tested on the converter's laboratory prototype. Another interesting approach, that will be considered, is based on the use of integrated topologies in which two different power conversion stages are merged by sharing the same power switch and control circuitry. In the resulting converter, power factor correction and LED current regulation are thus performed by two combined semi-stages in which both the input power and the output current have to be managed by the same shared switch. Compared with a conventional two-stages configuration, lower circuit complexity and cost, reduced component count and higher compactness can be achieved through integration, at cost of increased stress levels on the power switch and of losing a degree of freedom in converter design. Galvanic isolation can be provided or not depending on the topologies selected for integration. If non-isolated topologies are considered for both semi-stages, the user safety has to be guaranteed by assuring mechanical isolation throughout the LED lamp case. The issue, deriving from the need of smoothing the pulsating power absorbed from the line while avoiding the use of short lifetime electrolytic capacitors, will be addressed. A set of integrated topologies, used as HBLED lamp power supplies, will be investigated and a generalized analysis will be presented. Their input line voltage ripple attenuation capability will be examined and a general design procedure will be described. Moreover, a novel integrated solution, based on the use of a double buck converter, for an about 15W rated down-lighting application will be presented. The analysis performed, together with converter design and power factor correction concerns will be carefully discussed and the main outcomes of the tests performed at simulation level will be provided. The last kind of approach to be discussed is based on a multi-stage structure that results to be a suitable option for medium power applications, like street lighting, in which compactness is not a major concern. By adopting such kind of solution it is, indeed, possible to optimize converter’s behavior both on line and on load side, thereby guaranteeing both an effective power factor correction at the input and proper current regulation and dimming capability at the output. Galvanic isolation can be provided either by the input or the output stage, resulting in a standard two stage configuration, or by an additional intermediate isolated DC-DC stage (operating in open loop with a constant input/output voltage conversion ratio) that namely turns the AC/DC converter topology into a three stage configuration. The efficiency issue, deriving from the need of multiple energy processing along the path between the utility grid and the LED load, can be effectively addressed thanks to the high flexibility guaranteed by this structure that, relaxing the design constraint, allows to easily optimize each stage. A 150W nominal power rated ballast for street solid state lighting applications, based on the latter (three stage) topology, has been investigated. The analysis performed, the design procedure and the simulations outcomes will be carefully described, as well as the experimental results of the tests made on the implemented laboratory prototype

Development of Hybrid Active-Passive Solar Lighting System

The main idea of this project is to develop Hybrid Active-Passive Solar Lighting System for domestic usage. The demand of electrical power for the lighting system keep increasing in the domestic area especially at house which cause more fossil fuel burning to produce more electricity. To reduce the power consumption from the conventional power supply, some of the lighting system can get power from the renewable energy such as Solar Energy. The project carries out the feasibility studies on solar energy characteristics to determine whether it is possible to use solar electricity for lighting system

Controladores LED eficientes para aplicações de iluminação geral

Mestrado em Engenharia Eletrónica e TelecomunicaçõesThe ever growing energy consumption trends and its impact on the environment has triggered worldwide attention. This has motivated several measures, such as the Kyoto protocol, or the 20 20 20 European strategy, aiming at the reduction of energy consumption. Globally, these measures defend a better and efficient usage of the available energy. This in turn is strongly linked to public awareness and the introduction of efficient electronic equipment. Public street lighting is a good example of these trends, where both aspects are of the utmost importance. The introduction of power LEDs as future lighting devices has motivated several advances coping with these strategies. On one side, LEDs are able to deliver higher efficiency when compared to conventional lighting devices. This has triggered the replacement of old style luminaires by LED based ones. However, their high cost has prevented full adoption and at the present stage, is acting as a slowing down force against this replacement trend. Better solutions are under research on the framework of several European projects. Power LEDs are solid-state devices able to support fast switching, a feature which was not fully supported by conventional lighting devices. Combining this feature with environmental sensing and intelligent control may lead to better power savings. A simple approach would be to consider the that the actual lighting demands depend on the street usage and surrounding lighting levels. For this purpose, the combination of twilight sensors, motion detectors and intelligent control schemes may provide a suitable approach. This way, the real lighting demands can be effectively taken into consideration, providing luminaires able to consume the least possible energy. For this to become a reality several challenges have to be addressed. One of the most important challenges is the LED driver design. Modern lighting systems based on LEDs, replace the traditional ballasts by LED drivers. When efficiency is a major concern, such as in public street lighting, these drivers have to be designed in order to be the most robust and efficient as possible. Recurring solutions resort to switched mode power supplies, able to support light dimming. One of the major problems with these drivers is the fact that their efficiency decreases for lower dimming levels. This is of the utmost importance for public street lighting, as most of the time during night, the luminaires are on a low lighting level (as changes to high lighting conditions depend on street usage). Thus, in order to promote better power savings, the efficiency of the driver should be high for both lighting conditions. Commercially available drivers, exhibit efficiencies on the 90% range for the high lighting conditions, with only 40% to 60% under the low lighting. On the framework of this master dissertation it was investigated the problem of LED driver design aiming at the highest possible uniformity of the efficiency curve, under different loading and dimming conditions. The selected approach was based on quasi-resonant flyback converter, backed up by an active power factor correcting block. The designed driver supports remote configuration and monitoring as well as sensor integration. The archived results show that this driver achieves a peak efficiency of 93% under maximum load and 100% duty-cycle. The efficiency for low dimming conditions (10% duty-cycle) achieves 75%.As tendências de consumo de energia cada vez maior e seu impacto sobre o meio ambiente tem captado a atenção a nível mundial. Isso tem motivado várias medidas, tais como o Protocolo de Quioto, ou a estratégia Europeia 20 20 20, visando a redução do consumo de energia. Globalmente, estas medidas defendem um uso melhor e eficiente da energia disponível. Este, por sua vez, está fortemente ligado à consciência pública e à introdução de equipamento eletrónico eficiente. A iluminação pública é um bom exemplo dessas tendências, em que ambos os aspetos são de extrema importância. A introdução de LEDs como dispositivos de iluminação tem motivado vários avanços que lidam com essas estratégias. De um lado, os LEDs são capazes de oferecer uma maior eficiência quando comparados com dispositivos de iluminação convencionais. Isso provocou a substituição de luminárias convencionais por luminárias baseadas em LED. No entanto, o custo elevado destes dispositivos tem impedido a adoção plena e na fase atual, está mesmo a atuar como uma força negativa contra esta tendência de substituição. Melhores soluções estão sob investigação no âmbito de vários projetos europeus. Os LEDs são dispositivos de estado sólido, capazes de suportar a comutação rápida, uma característica que não é totalmente suportada por dispositivos de iluminação convencionais. Combinando esta característica com sensores ambientais e controlo inteligente pode-se ambicionar melhores poupanças energéticas. Uma abordagem simples seria a de considerar o que as exigências de iluminação reais dependem do uso das ruas e os níveis de iluminação circundantes. Para este efeito, a combinação de sensores de crepúsculo, detetores de movimento e regimes de controlo inteligentes podem propiciar uma abordagem adequada. Desta forma, os requisitos reais de iluminação podem ser efetivamente considerados, fornecendo luminárias capazes de consumir apenas a energia necessária. Para que isto se torne uma realidade vários desafios têm de ser vencidos. Um dos desafios mais importantes é o projeto LED driver. Nos sistemas de iluminação modernos baseados em LEDs, substitui-se os balastros convencionais por LED drivers. Quando a eficiência é importante, como no caso da iluminação pública, O LED driver têm de ser concebido de forma a ser o mais robusto e eficiente possível. Soluções recorrentes usam a fontes de alimentação comutadas, capazes de suportar o escurecimento adaptativo do fluxo luminoso. Um dos problemas principais no projeto destes drivers é o facto de a sua eficiência diminuir para níveis de regulação mais baixos. Isto é de extrema importância para a iluminação pública, pois na maioria dos casos durante a noite, as luminárias estão num nível de iluminação de baixo. Assim, com a finalidade de promover uma melhor economia de energia, a eficiência do driver deve ser elevada para ambas as condições de iluminação. Drivers comercialmente disponíveis, exibem eficácias na gama de 90% com elevado fluxo luminoso, e apenas 40% a 60% na condição de baixo fluxo luminoso. No âmbito desta dissertação de mestrado foi investigado o problema do projeto de driver LED visando a maior uniformidade possível da curva de eficiência, sob diferentes condições de carga e de fluxo luminoso. A abordagem escolhida foi baseada no conversor flyback quasi-ressonante, apoiado por um bloco de correção de fator de potência ativa. O driver projetado suporta configuração e monitorização remota, bem como de integração de sensores. Os resultados alcançados mostram que este driver atinge um pico de eficiência de 93% na condição de carga máxima e máximo fluxo luminoso. A eficiência em condições de baixo fluxo luminoso é superior a 75%

Intrinsically Evolvable Artificial Neural Networks

Dedicated hardware implementations of neural networks promise to provide faster, lower power operation when compared to software implementations executing on processors. Unfortunately, most custom hardware implementations do not support intrinsic training of these networks on-chip. The training is typically done using offline software simulations and the obtained network is synthesized and targeted to the hardware offline. The FPGA design presented here facilitates on-chip intrinsic training of artificial neural networks. Block-based neural networks (BbNN), the type of artificial neural networks implemented here, are grid-based networks neuron blocks. These networks are trained using genetic algorithms to simultaneously optimize the network structure and the internal synaptic parameters. The design supports online structure and parameter updates, and is an intrinsically evolvable BbNN platform supporting functional-level hardware evolution. Functional-level evolvable hardware (EHW) uses evolutionary algorithms to evolve interconnections and internal parameters of functional modules in reconfigurable computing systems such as FPGAs. Functional modules can be any hardware modules such as multipliers, adders, and trigonometric functions. In the implementation presented, the functional module is a neuron block. The designed platform is suitable for applications in dynamic environments, and can be adapted and retrained online. The online training capability has been demonstrated using a case study. A performance characterization model for RC implementations of BbNNs has also been presented

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

Index to NASA Tech Briefs, 1975

This index contains abstracts and four indexes--subject, personal author, originating Center, and Tech Brief number--for 1975 Tech Briefs