Estimation of the light output power and efficiency of a XeCl dielectric barrier discharge exciplex lamp using one dimensional drift-diffusion model for various voltage waveforms

A XeCl dielectric barrier discharge (DBD) excilamp applied by pulsed and sinusoidal voltage waveforms is simulated using a 1-D drift–diffusion model. In both waveforms, the light output power depends not only on the gas mixture composition but also on the electrical parameters of each voltage waveform such as the frequency, the duty cycle, etc. At the same amplitude of the applied voltage and frequency, the light ultraviolet output efficiency of a pulsed voltage is higher than that of a sine voltage. These results obtained in this paper permit us to find out an appropriate power supply for a DBD excilamp

Pulsed Current-Mode Supply of Dielectric Barrier Discharge Excilamps for the Control of the Radiated Ultraviolet Power

UV excimer lamps are efficient narrowband sources of UV radiation with applications in various domains. The issue of controlling the UV emission by means of the power supply associated with such lamps favors pulsed current-controlled generators. After having established the previous statements, we propose a dedicated power converter topology which implements the needed performances. The analysis of the degrees of freedom of this structure shows the capability of this pulsed supply to realize the control of both the pulses’ current energy and of the mean power transferred to the lamp. Actual experimental realizations and measurement are presented and the feasibility and the performances of the proposed solutions are established

Sources d'Alimentation Électrique pour l'Étude et l'Utilisation Efficace des Lampes Excimer DBD

Avec l'objectif d'améliorer le rendement des lampes à excimères (Excilampe) à décharge à barrière diélectrique (DBD), un convertisseur en mode de courant, qui permet un ajustement précis de la puissance électrique injectée dans ce type des lampes, à été conçu et mis en oeuvre. Ce convertisseur fournit à la lampe un courant de forme d'onde carrée contrôlé au moyen de trois paramètres: l'amplitude, la fréquence et le rapport cyclique, pour obtenir un contrôle total de l'énergie électrique transmise à l'excilampe DBD. La mise en oeuvre intègre un transformateur élévateur comme interface entre la lampe et un commutateur. Les expériences démontrent le principe de fonctionnement de ce convertisseur, y compris les mesures de puissance du rayonnement UV. Les degrés de liberté du convertisseur sont utilisées pour analyser le comportement de la lampe sous différentes combinaisons de ces trois paramètres, et sont utilisés pour déterminer le point de fonctionnement optimal de la lampe. Ensuite, un convertisseur à résonance du type onduleur série, est proposé pour alimenter la lampe avec une grande efficacité électrique. Afin de contrôler effectivement la puissance de la lampe, le mode de fonctionnement de ce convertisseur utilise le mode de conduction discontinue et la commutation douce (ZCS), avec lequel on obtient aussi de faibles émissions électromagnétiques et l'on réduit les pertes de commutation. Les relations mathématiques obtenus à partir de l'analyse du diagramme de phase, ont été validées par des simulations et avec des résultats expérimentaux. Enfin, différentes topologies d'alimentations pour DBD sont comparées analytiquement et expérimentalement pour évaluer objectivement les avantages de chaque approche. Une des perspectives de ce travail est l'application de l'alimentation en créneaux pour l'étude de la performance d'autres types de réacteurs et d'excilampes DBD. ABSTRACT : With the aim to provide a scientific tool for the enhancement of the Dielectric Barrier Discharge (DBD) Excimer Lamps (Excilamp) performance, a current-mode converter that allows an accurate adjustment of the electrical power injected into one of those lamps, is designed and implemented. With the proposed converter, the current supplied to the lamp has a square shape, controlled by means of three parameters: amplitude, duty cycle and frequency, which provides full control of the lamp electrical power. Implementation is made considering a step-up transformer interfacing the high-voltage lamp with the converter. Experiments demonstrate the operating principle of this converter, including UV power measurements for a DBD XeCl Excilamp. The capabilities of the converter are used to analyze the lamp behavior under different combinations of these three parameters, illustrating its capabilities for finding the optimal operating point. Then a series-resonant inverter for the supply of DBD) excilamp is proposed. In order to effectively control the lamp power, the operating mode of this converter combines discontinuous current-mode and soft-commutation (ZCS), obtaining as well low electromagnetic emissions, and reduced switching losses. The mathematical relationships obtained from state plane analysis, are validated with simulations and experimental results. Finally, several topologies of DBDs power supplies are compared analytical and experimentally to elucidate the advantages of each approach. After this work, one of the perspectives is the application of the square-shape supply in the performance study of other types of DBD excilamps and DBD reactors

Optimizing the Operation of DBD Excilamps

Dielectric barrier discharge (DBD) excimer lamps are efficient and environmentally friendly sources of ultraviolet (UV). One of the challenges for this technology to be massively adopted is the optimization and effective management of the overall lamp-supply system. Accordingly, a methodology to study the impact of the operating point over the performance and operation of a DBD UV excilamp is developed and experimentally validated. The DBD operating point is parametrically adjusted by means of the power supply current with three independent variables: intensity, frequency,and duty cycle. This methodology allows the determination of the optimal operating point for the particular excilamp under study. These supplying conditions will be later achieved by means of a dedicated electrical generator, which has to be especially designed according to these specifications. It is found that an increment in the current intensity has a positive impact on the lamp efficiency and also leads to the existence of more filamentary discharges. Also, a relation between the energy of the pulse supplied to the DBD and the reactor efficiency can be established. For certain levels of UV power, energy savings on the reactor higher than 50% are attained by proper selection of the operating point

Power Supplies for the Study and Efficient use of DBD Excimer UV Lamps

With the aim to provide a scientific tool for the enhancement of the Dielectric Barrier Discharge (DBD) Excimer Lamps (Excilamp) performance, a current-mode converter that allows an accurate adjustment of the electrical power injected into one of those lamps, is designed and implemented. With the proposed converter, the current supplied to the lamp has a square shape, controlled by means of three parameters: amplitude, duty cycle and frequency, which provides full control of the lamp electrical power. Implementation is made considering a step-up transformer interfacing the high-voltage lamp with the converter. Experiments demonstrate the operating principle of this converter, including UV power measurements for a DBD XeCl Excilamp. The capabilities of the converter are used to analyze the lamp behavior under different combinations of these three parameters, illustrating its capabilities for finding the optimal operating point. Then a series-resonant inverter for the supply of DBD) excilamp is proposed. In order to effectively control the lamp power, the operating mode of this converter combines discontinuous current-mode and soft-commutation (ZCS), obtaining as well low electromagnetic emissions, and reduced switching losses. The mathematical relationships obtained from state plane analysis, are validated with simulations and experimental results. Finally, several topologies of DBDs power supplies are compared analytical and experimentally to elucidate the advantages of each approach. After this work, one of the perspectives is the application of the square-shape supply in the performance study of other types of DBD excilamps and DBD reactors

System for experimental investigation of DBD excilamps in view of control and optimization of UV emission

This paper presents the design of a system aimed at characterizing a diverse set of dielectric barrier discharge UV lamps. This experimental bench allows the study of the lamps performances regarding UV emission maximization and energy conversion optimization. It includes a current-mode pulsed power supply for the lamps, the design of which is detailed. This converter presents 3 degrees of freedom (DOF) can control and adjust independently the frequency, amplitude and duration of the current pulses injected into the lamps. Theoretical modeling of the lamps, by means of equivalent electrical circuits, is used to define the most interesting operating points to be explored, as well as for the converter’s design; these models are afterwards validated by experimental tests on the entire set of lamps. The operation of the bench is controlled by a supervising program: the latter manages the data acquisition and performs sweeps of the DOFs of the pulsed current. Examples of analyzes, oriented toward optimization of electric to UV energy conversion, are shown

A High Voltage High Frequency Resonant Inverter for Supplying DBD Devices with Short Discharge Current Pulses

In this paper, the merits of a high-frequency resonant converter for supplying dielectric barrier discharges (DBD) devices are established. It is shown that, thanks to its high-frequency operating condition, such a converter allows to supply DBD devices with short discharge current pulses, a high repetition rate, and to control the injected power. In addition, such a topology eliminates the matter of connecting a high-voltage transformer directly across the DBD device and avoids the issues related to the parasitic capacitances of the latter which disturbs the control the power transfer to the plasma. The design issues of the converter, including the inverter and its switches, the resonant inductor, and the parameter drift compensation are studied. An experimental validation is performed: a mega Hertz resonant converter using GaN FET switches has been manufactured and tested with an excimer lamp

Relación de transformación óptima para fuente de alimentación de lámpara de descarga de barrera dieléctrica

Las lámparas excimer de descarga de barrera dieléctrica (DBD), son modeladas como cargas capacitivas y requieren de fuentes de alimentación de alto voltaje para establecer la descarga en el gas. Debido a la baja capacitancia de la lámpara, la operación de la fuente es afectada por las capacitancias parasitas de sus componentes. Con el fin de entender los efectos de las capacitancias y seleccionar un convertidor óptimo, este proyecto presenta el análisis teórico del convertidor resonante boost considerando las capacitancias de los interruptores y el impacto de la relación de transformación en la eficiencia del sistema. El convertidor óptimo es implementado y utilizado para la validación experimental.Dielectric Barrier Discharge (DBD) excimer lamps are modeled as capacitive loads and require a high voltaje power supply. Due to the low equivalent capacitance of the lamp, the operation of the power supply is highly affected by the parasitic capacitances of its components. In order to understand the effects of the parasitic capacitances and select an optimum converter, this project presents the theoretical analysis of the boost based resonant converter considering the switches capacitances and studies the impact of the transformer turns ratio in the efficiency of the system. The optimum converter is implemented and used for the experimental validation.Magíster en Ingeniería ElectrónicaMaestrí

Etude des décharges à barrières diélectriques, applications à des sources de photons à gaz rare

Depuis plusieurs années, les lampes à excimères font l'objet de nombreuses recherches. La génération du rayonnement UV et VUV contrôlée par une décharge à barrières diélectriques (DBD) par l'excitation d'un gaz rare ou d'un gaz rare halogène représente un concept prometteur pour d'autre type de source de lumière. Cette recherche se divise en deux parties, une partie expérimentale qui caractérise le plasma à pression en dessous de 150 Torr, et une partie numérique qui caractérise le plasma à une pression au-dessus de 400 Torr. La partie expérimentale concerne la caractérisation optique et électrique d'une décharge à barrière diélectrique. Le banc expérimental se repose essentiellement sur une excitation impulsionnelle, un réacteur et la présence de gaz rare. L'objectif de cette partie est d'établir un bilan général de notre lampe pour essayer de l'optimiser, et de déterminer les éléments qui influencent le dépôt de la puissance moyenne et les différents résultats de l'efficacité. La partie numérique concerne l'utilisation d'un modèle cinétique électrique pour une description homogène d'une décharge à barrières diélectriques, le modèle de la décharge se base sur un couplage de trois éléments à savoir : la cinétique réactionnelle, l'équation de Boltzmann et le circuit d'excitation. Le principal objectif de cette partie du travail est d'optimiser le dépôt d'énergie, ainsi que l'efficacité lumineuse de notre source DBD, produite par différents formes d'excitation sinusoïdale, impulsionnelle et burst. Finalement, l'optimisation du dépôt d'énergie dans les DBDs implique une meilleure compréhension des phénomènes physiques dans le plasma et des mécanismes cinétiques essentiels conduisant à la formation ou à la disparition des excimères. Les phénomènes électriques liés aux interactions entre le circuit d'excitation et la décharge affectent eux aussi d'une manière significatrice l'énergie déposée dans le milieu plasma. Ces phénomènes sont expliqués tout au long de ce manuscrit.For several years, excimer lamps have been the subject of numerous research. The generation of UV and VUV radiation controlled by a dielectric barrier discharge (DBD) through the excitation of a rare gas or halogen rare gas represents a promising concept for other type of light source. This research is divided into two parts, an experimental part which characterizes the plasma at pressure below 150 Torr, and a numerical part which characterizes the plasma at pressure above 400 Torr. The experimental part concerns the optical and electrical characterization of a dielectric barrier discharge. the experimental set up is based mainly on a pulse excitation, a reactor and the presence of noble gas. The objective of this part is to establish a general diagnostic of our lamp in order to try to optimize it, and to determine the elements that influence the deposition of the average power and the different efficiency results. The numerical part concerns the use of an electrical kinetic model for a homogeneous description of a dielectric barrier discharge, the model of the discharge is based on a coupling of three elements namely: the reaction kinetics, the Boltzmann equation and the excitation circuit. The main objective of this part of the work is to optimize the energy deposition and the luminous efficiency of our DBD source, produced by different forms of sinusoidal, pulse and burst excitation. Finally, the optimization of energy deposition in DBDs implies a better understanding of the physical phenomena in the plasma and the essential kinetic mechanisms leading to the formation or disappearance of excimers. The electrical phenomena related to the interactions between the excitation circuit and the discharge also significantly affect the energy deposited in the plasma medium. These phenomena are explained throughout this manuscript

Estimation of the light output power and efficiency of a XeCl dielectric barrier discharge exciplex lamp using one dimensional drift-diffusion model for various voltage waveforms

International audienceA XeCl dielectric barrier discharge (DBD) excilamp applied by pulsed and sinusoidal voltage waveforms is simulated using a 1-D drift–diffusion model. In both waveforms, the light output power depends not only on the gas mixture composition but also on the electrical parameters of each voltage waveform such as the frequency, the duty cycle, etc. At the same amplitude of the applied voltage and frequency, the light ultraviolet output efficiency of a pulsed voltage is higher than that of a sine voltage. These results obtained in this paper permit us to find out an appropriate power supply for a DBD excilamp