In this article, a Pareto multiobjective optimization is performed to design new luminaires. The effort involves finding the optimal forward current, the number of light-emitting diodes (LEDs), and a proper heat sink by taking into account the cost, energy consumption, and environmental impact (carrying out a cradleto-grave life-cycle analysis). Three commercial white LEDs were studied and modeled in terms of their optical, electrical, thermal, and aging performance. The multiobjective methodology was also applied to other lamps (incandescent, halogen, and fluorescent), which indicated that LED lighting has great potential for energy and cost savings, with minimal long-term environmental impact.

In this paper, a Pareto multiobjective optimization is performed to design new luminaires, finding the optimal forward current, number of LEDs and proper heatsink by taking into account the cost, the energy consumption and the impact on the environment (life cycle analysis from cradle to grave). Three commercialized white LEDs have been studied and modelled in terms of optical, electrical, thermal and aging performances. The multiobjective methodology is also applied to other lamps (incandescent, halogen, fluorescent), indicating that LED lighting has a great potential of energy and cost savings with a minimization of environmental impacts on the long run.

Light emitting diodes (LEDs) are commonly expected to be the future of lighting because of a high luminous efficacy, a long lifetime and a high color rendering index (CRI). Nevertheless, the performance and the reliability of an LED are strongly dependent on the LED junction temperature. This paper presents a multi-objective methodology to find the optimal forward current subject to the annualized cost of the luminaire (initial capital cost, replacement cost, operation and maintenance cost...) and the annualized energy consumption. A simple LED model based on empirical data has been developed and takes into account optical, electrical, thermal and ageing behaviour. Three different white LEDs have been evaluated through several combinations of forward currents and heatsinks to satisfy a given mission profile. A set of optimal solutions has been determined by Pareto optimization.

Light Emitting Diodes (LED) are semiconductor devices which, combined to phosphors, emit white light with high efficacy surpassing conventional light sources. Elementary LED is not suffisant to light a piece. It need to be associated with others and combined to a power supply to constitute a complete luminaire. Actually, "wall -plug" efficacy drops a lot due to factors such as optical attenuation, electrical connections losses, thermal impact, ... To develop optimal electrical supply, a study was conducted to increase knowledge on interactions between LEDs technologies, their topology, current level supply and luminous efficacy ..., A more precise electrical model than classical used for light was developed. Simulation results on original LED matrix with its new modeling are shown. An experimental board was developed to validate our approach with real electrical characterizations.

Les Diodes Electro-Luminescentes (DEL ou LED : Light Emitting Diodes en anglais) sont des composants semi-conduteurs qui, combines a un luminophore, emettent de la lumiere avec une tres bonne efficacite (independamment de l'alimentation) surpassant les sources de lumiere conventionnelles. Les LEDs sont generalement associees sous diverses topologies pour former des sources ou luminaires dites a LED. Bien que leur efficacite au niveau de chaque composant elementaire soit tres bonne, elle peut chuter a cause de plusieurs facteurs comme les optiques, les pertes electriques ou l'impact thermique. Nous etudie l'influence d'associations et du niveau de courant applique sur l'efficacite des LED en simulation et avons valide notre approche par des resultats experimentaux.

With the vanishing of the fossil primary resources and the carbon impact issues, the efficient use of energy has become a major priority. Lighting is an important element of expenditure as it is easy to act on it. The Light Emitting Diode (LED) technology opens many perspectives in this field due to its higher energy efficiency. LED could indeed become in a near future a replacement for fluorescent tubes. LED's tubes have specific thermal and electrical needs; this work is focused therefore on optimization studies in terms of association topologies: serial versus parallel. The starting point is electrical equivalent models extracted from single LED. The choice of combinations is guided by the required performance in terms of light quality by paying attention to the overall consumption of the lighting system. The final target is the evaluation of losses reduction when the individual AC/DC conversion circuits integrated in the lamp bases are replaced by a DC/DC global distribution scheme. This approach was adopted to power the lighting of single room from a low DC voltage weakly regulated power grid.

With the vanishing of the fossil primary resources and the carbon impact issues, the efficient use of energy has become a major priority. Lighting is an important element of expenditure as it is easy to act on it. The Light Emitting Diode (LED) technology opens many perspectives in this field due to its higher energy efficiency. LED could indeed become in a near future a replacement for fluorescent tubes. LED's tubes have specific thermal and electrical needs; this work is focused therefore on optimization studies in terms of association topologies: serial versus parallel. The starting point is electrical equivalent models extracted from single LED. The choice of combinations is guided by the required performance in terms of light quality by paying attention to the overall consumption of the lighting system. The final target is the evaluation of losses reduction when the individual AC/DC conversion circuits integrated in the lamp bases are replaced by a DC/DC global distribution scheme. This approach was adopted to power the lighting of single room from a low DC voltage weakly regulated power grid.