14 research outputs found
Characterization of Acoustic Resonance in a High Pressure Sodium Lamp
No full textWith the last decades, the high pressure sodium (HPS) lamp has been supplied in high frequency in order to increase the efficacy of the lamp/ballast system. However, at some given frequencies, standing acoustic waves, namely acoustic resonance (AR), might develop in the burner and cause lamp luminous fluctuation, extinction and destruction in the most serious case. As we seek for a control method to detect and avoid the lamp AR some main characteristics of the acoustic resonances in a 150W HPS lamp are presented in this paper,. The first one is the characteristic of the lamp AR threshold power, the second one is the differences between forward and backward frequency scanning effects during lamp open loop operation. Thirdly, lamp AR behaviour in closed loop operation with an LCC half bridge inverter will be presented and leads to a new point of view and a change in the choice of the AR detection method. These characteristics allow us to further understand the AR and to better control the lamp
Supply and control methods for acoustic resonances avoidance in high intensity discharge lamp
No full textGrâce au développement de la technologie des semi-conducteurs, les ballasts électroniques fonctionnant en haute fréquence offrent des avantages considérables par rapport aux ballasts électromagnétiques conventionnels. Il en résulte une augmentation de la durée de vie de la lampe, une diminution du volume et du poids du système et surtout un meilleur contrôle de son fonctionnement afin de réduire notamment la consommation électrique. Parmi des lampes à décharge, la lampe sodium haute pression a une excellente efficacité lumineuse et une longue durée de vie. Pourtant, quand la lampe fonctionne en haut fréquence, des perturbations de type « résonance acoustique (RA) » peuvent entraîner l’instabilité de la décharge, son extinction ou pire, la destruction de la lampe. Cette thèse, intitulée « Modes d’Alimentation et de Commande des lampes sodium haute pression en vue d’éviter les résonances acoustiques », traite de plusieurs problèmes. Les caractéristiques de la décharge haute pression, le phénomène de RA, ses conditions d’excitation (notamment au travers d’un phénomène d’hystérésis original) et la variation des paramètres électriques due à la présence de résonances acoustiques dans la lampe, ont été étudiés. Les résultats sont issus de travaux de simulation et expérimentaux menés au sein du laboratoire LAPLACE. Grâce à ces acquis fondamentaux, plusieurs nouvelles méthodes d’alimentation par l’injection de signaux à fréquences proches ont été proposées dans nos travaux. Il s’agit d’éviter la résonance acoustique dans la lampe alimentée par un ballast de structure très réduite par rapport aux solutions classiques. Cette méthode est basée sur le choix judicieux des signaux injectés dans la lampe et leur répartition, (alimentation par deux, trois ou cinq signaux, répartition symétrique, asymétrique totale ou partielle). Le résultat est un meilleur étalement du spectre et donc une réduction de puissances harmoniques sélectionnées permettant de s’adapter, à terme aux conditions d’excitation des RA, mais aussi les limitations de ces méthodes compte tenu du facteur crête. Enfin, différents types de commande en boucle fermée sont proposés, ils permettent d’assurer la stabilité de la décharge et le contrôle des puissances imposées dans la lampe. Les études théoriques, en simulation et expérimentales qui ont été conduites nous ont permis d’aboutir à des résultats concluants.For high pressure sodium (HPS) lamps, the progress of semi-conductor technology has provided considerable advantages in the design of high frequency operated electronic ballasts, compared to conventional electromagnetic ballasts. The advantages deal with lamp lifetime improvement, ballast volume and mass reduction, and particularly with a better control of lamp operation for optimized power consumption. Among discharge lamps, high pressure sodium (HPS) lamp has excellent efficacy and long lifetime. However, when it is operated at high frequency, discharge perturbation namely “acoustic resonances (AR)” can provoke some lamp arc instabilities, extinction or, even worst, lamp destruction. The present thesis, entitled “Supply and control methods for acoustic resonances avoidance in high intensity discharge lamps” deals with several matters. High intensity discharge (HID) characteristics, AR phenomenon, its excitation conditions (including the original features of AR hysteresis) and lamp electrical parameters variation due to AR presence, will be studied. The obtained results were provided by simulations and experimentations carried out in LAPLACE laboratory. Thanks to the acquired results of previous studies, several novel lamp supply strategies via adjacent frequency signals injection were proposed. The main concepts here consist in the avoidance of AR presented in a lamp supplied by designed electronic ballast with reduced structure, compared to classical solutions. Otherwise, the presented methods are based on pertinent choices of injected signals applied to the lamp and their frequency distributions (two, three or five signals and symmetric, partial asymmetric or total asymmetric signals). The studies actually showed better spreading of signal spectrum and power harmonic amplitudes reduction adapted to AR excitation conditions, while taking into account crest factor limitation. Finally, different control laws (PI, Hysteresis, Self-oscillation, Resonant controllers) were also proposed in order to guarantee lamp discharge stabilization and power controls. The theoretical and experimental studies including simulations were conducted to reach concluding results of our works
Modes d'Alimentation et de Commande des lampes sodium haute pression en vue d’éviter les résonances acoustiques
No full textGrâce au développement de la technologie des semi-conducteurs, les ballasts électroniques fonctionnant en haute fréquence offrent des avantages considérables par rapport aux ballasts électromagnétiques conventionnels. Il en résulte une augmentation de la durée de vie de la lampe, une diminution du volume et du poids du système et surtout un meilleur contrôle de son fonctionnement afin de réduire notamment la consommation électrique. Parmi des lampes à décharge, la lampe sodium haute pression a une excellente efficacité lumineuse et une longue durée de vie. Pourtant, quand la lampe fonctionne en haut fréquence, des perturbations de type « résonance acoustique (RA) » peuvent entraîner l’instabilité de la décharge, son extinction ou pire, la destruction de la lampe. Cette thèse, intitulée « Modes d’Alimentation et de Commande des lampes sodium haute pression en vue d’éviter les résonances acoustiques », traite de plusieurs problèmes. Les caractéristiques de la décharge haute pression, le phénomène de RA, ses conditions d’excitation (notamment au travers d’un phénomène d’hystérésis original) et la variation des paramètres électriques due à la présence de résonances acoustiques dans la lampe, ont été étudiés. Les résultats sont issus de travaux de simulation et expérimentaux menés au sein du laboratoire LAPLACE. Grâce à ces acquis fondamentaux, plusieurs nouvelles méthodes d’alimentation par l’injection de signaux à fréquences proches ont été proposées dans nos travaux. Il s’agit d’éviter la résonance acoustique dans la lampe alimentée par un ballast de structure très réduite par rapport aux solutions classiques. Cette méthode est basée sur le choix judicieux des signaux injectés dans la lampe et leur répartition, (alimentation par deux, trois ou cinq signaux, répartition symétrique, asymétrique totale ou partielle). Le résultat est un meilleur étalement du spectre et donc une réduction de puissances harmoniques sélectionnées permettant de s’adapter, à terme aux conditions d’excitation des RA, mais aussi les limitations de ces méthodes compte tenu du facteur crête. Enfin, différents types de commande en boucle fermée sont proposés, ils permettent d’assurer la stabilité de la décharge et le contrôle des puissances imposées dans la lampe. Les études théoriques, en simulation et expérimentales qui ont été conduites nous ont permis d’aboutir à des résultats concluants. ABSTRACT : For high pressure sodium (HPS) lamps, the progress of semi-conductor technology has provided considerable advantages in the design of high frequency operated electronic ballasts, compared to conventional electromagnetic ballasts. The advantages deal with lamp lifetime improvement, ballast volume and mass reduction, and particularly with a better control of lamp operation for optimized power consumption. Among discharge lamps, high pressure sodium (HPS) lamp has excellent efficacy and long lifetime. However, when it is operated at high frequency, discharge perturbation namely “acoustic resonances (AR)” can provoke some lamp arc instabilities, extinction or, even worst, lamp destruction. The present thesis, entitled “Supply and control methods for acoustic resonances avoidance in high intensity discharge lamps” deals with several matters. High intensity discharge (HID) characteristics, AR phenomenon, its excitation conditions (including the original features of AR hysteresis) and lamp electrical parameters variation due to AR presence, will be studied. The obtained results were provided by simulations and experimentations carried out in LAPLACE laboratory. Thanks to the acquired results of previous studies, several novel lamp supply strategies via adjacent frequency signals injection were proposed. The main concepts here consist in the avoidance of AR presented in a lamp supplied by designed electronic ballast with reduced structure, compared to classical solutions. Otherwise, the presented methods are based on pertinent choices of injected signals applied to the lamp and their frequency distributions (two, three or five signals and symmetric, partial asymmetric or total asymmetric signals). The studies actually showed better spreading of signal spectrum and power harmonic amplitudes reduction adapted to AR excitation conditions, while taking into account crest factor limitation. Finally, different control laws (PI, Hysteresis, Self-oscillation, Resonant controllers) were also proposed in order to guarantee lamp discharge stabilization and power controls. The theoretical and experimental studies including simulations were conducted to reach concluding results of our works
Caractérisation et Modélisation Numérique 2D des Résonances Acoustiques d’une Lampe à Décharge
No full textNational audienc
Analysis of open-phase degradation in a mono-inverter double PMSM system
No full textInternational audienceThis paper presents the studies of degradation mechanisms in a mono-inverter multi-machine permanent magnet synchronous (PMS) system subjected to stator phase disconnection. The system principle operation in normal condition will first be presented. The degradation scenarios and their consequences for motor phase and inverter phase disconnection modes will be analyzed in detail. Control solutions under the given degraded condition are also proposed and based on analytical method and Saber simulations. This study contributes to the availability improvement of multimotor/mono-inverter system
Interpolation modelling of acoustic resonance in high pressure sodium lamp
No full textInternational audienc
HPS lamp control with adjacent frequency signal injection for acoustic resonance avoidance
No full textInternational audienc
A COMPARISON OF OSPFV3 AND EIGRPV6 IN A SMALL IPV6 ENTERPRISE NETWORK
No full textAs the internet slowly transitions towards IPv6, the routing protocols that
are used to forward traffic across this global network must adapt to support this
gradual transition. Two of the most frequently discussed interior dynamic routing
protocols today are the IETF’s OSPF and Cisco’s EIGRP routing protocol. A wealth
of thesis has compared OSPF and EIGRP in terms of converge times and resource
usage, however few papers have assessed the performance of each when
implementing their respective security mechanisms. Therefor a comparison of
OSPFv3 and EIGRPv6 conducted using dedicated Cisco Packet Tracer.
This final project in introduce each protocol and OSPFv3 security
mechanism, before conducting a comparison of OSPFv3 and EIGRPv6 using Cisco
Packet Tracer equipment. Based on the simulation results, a conclusion is drawn to
reveal the findings of this project and which protocol performs the best upon
implementing their respective security mechanisms within a small IPv6 enterprise
network.
The thesis has discussed two eminent interior routing protocols. Their
performances have been analyzed considering the parameters of packet loss, end to
end delay and convergence timing. In analysis, author has found that EIGRPv6
performs much better that OSPFv3 in all these three cases. So our recommendation
is to use EIGRPv6 as an interior routing protocols in IPv6 network. But the main
disadvantage of EIGRPv6 is that, this routing protocols can only be used in the
Cisco’s routers only. In this case, OSPFv3 is the best alternative. In future, author
are comparing these routing protocols with considering the security issues of IPv6.
The work also extended to the real life devices
Injection of adjacent frequency signals for acoustic resonance avoidance in HPS lamp
No full textInternational audienc
Handling Solid and Hazardous Waste by Waste Pickers: A Case Study of Phnom Penh, Cambodia
No full textabstract: The handling of waste encompasses the following processes: recycling, collection, treatment, and disposal. It is crucial to provide a cost-effective waste management system that improves public health and reduces environmental risks. In developing countries, proper handling of solid and hazardous wastes remain severely limited in urban cities if the industries and hospitals producing it do not take responsibility. Recycling and reusing of 12% of total waste in Phnom Penh is an active industry in Cambodia, driven by an informal network of waste pickers, collectors, and buyers. This thesis examines the environmental situation of solid and hazardous wastes in Phnom Penh. The socio-economic background of waste pickers and their current practices for handling solid and hazardous wastes will be mainly discussed in order to understand health and sanitation impacts and risks for disposal of solid and hazardous waste by these informal waste pickers. Surveys and interviews with the following sources are conducted: waste pickers, community members, observation at local dumpsites, governmental officials, and other non-government organization agencies in Phnom Penh, Cambodia. This thesis reports the external and internal factors that hinder safety and cost-effective management for disposal of solid and hazardous wastes. Multiple literature reviews are assessed in regards to the health effects, economic, and social impacts in developing countries. Evidentially, after attending several training and environmental awareness-raising programs, waste pickers expressed concerns about their health and the environment. Instead of receiving support, waste pickers are under economic pressure to use improper tools for waste picking, to stop working, get access to health care/service, to change their career, and prevent contact to limit serious communicable diseases and disability. As a result, the government and other related government agencies have made an effort to establish sanitation handling, treatment, and disposal systems by closing the old dumpsite. Due to limited entrepreneurship and business experience after training, most waste pickers cannot initiate micro business or find new jobs and then resume their waste picking. In conclusion, this thesis proposed that there are alternative technologies and management methods that will allow waste pickers to maintain employment while minimizing hazardous waste. Some examples of alternatives for waste pickers are establishing a material recovery center and alternative higher income occupation.Dissertation/ThesisM.S.Tech Human and Social Dimensions of Science and Technology 201
