Brahim Mrabet

Effect of a pulsed power supply on the spectral and electrical characteristics of HID lamps

Results of spectral and photometric measurements are presented for pulsed power operated high intensity discharges (HIDs). This investigation is related to the application of a pulsed power supply for pile driving of HID lamps. Specifically, we are interested in controlling the spectral response radiation of visible and ultraviolet (UV) lines for tertiary treatment of water using UV radiation. Simulations based on a physical model of the lamps were conducted. These results relate to the radial temperature, line intensity and electrical properties (voltage, power and conductivity). Good agreement has been found between the results of the simulations and the experimental findings.

Integrating cylinder radiometry and photometry: Application to radiant flux and irradiance measurements

Abstract In this paper, we present the detail calculations of the indirect spectral irradiance E(λ) as a function of the spectral radiant flux Φt(λ) of a radiating source. This relation is used to predict the integrating cylinder irradiance for a given input radiant flux as a function of the geometrical parameters and reflectivity called “multiplier constant”. The radiation transfer within a cylindrical enclosure composed of three different surfaces, the inside circular surface and the two bases in the ends, has been examined. The configuration factor is introduced. Then all the configuration factors needed for our calculation have been given in analytical form.

HID lamps under low frequency square wave operation: Experimental Evaluation of Dimming effects

In this paper, the dimming effects on the photometric and electric characteristics of high intensity discharge lamps supplied by a low frequency square waveform are evaluated. For this evaluation an electronic ballast is presented. The ballast consists of a current source, AC/DC converter and a full-bridge inverter. The electronic supply provides to the lamp a different form of current excitation (square waves with variable short drops). Dimming control and the characteristics of low frequency operated high intensity discharge lamps are described. The lamp is represented in a simulation by its conductance model and coupled to its electronic power supply. Experimental results are shown and compared with the simulation. A dimming range from 100% to about 60% has been achieved.

Behaviour of a high-intensity discharge lamp fed by a high-frequency dimmable electronic ballast

The main advantages of high-frequency electronic ballasts for high-intensity discharge lamps are high luminous efficacy, small size, lightweight and longer lifetime. This is why high-intensity discharge lamps operating at high frequency are widely used. This paper proposes an approach for designing resonant circuit electronic ballasts controlled by frequency variation for high-intensity discharge lamps. The proposed technique including an AC/DC rectifier, a power factor correction circuit and a DC/AC half bridge inverter. These electronic ballasts offer a wide range of dimming controls and can avoid acoustic resonance. However, under dimming, the electric and photometric characteristics of the lamp change. In order to study these effects under the process of dimming, this work studies the lamp properties by varying both lamp power and operating frequency.

Assessment of the effect of a pulsed power supply on the HgTlI lamp

The objective of this work is to study the influence of a pulsed power supply on the energy efficiency of high-intensity discharge lamps in comparison with a pseudo-continuous ballast. The results presented in this paper concern the dynamic behaviour of discharges in mercury vapour doped with thallium iodide. The acquisition of the arc current, arc voltage and spectral radiation enables us to investigate the influence of the pulsed power supply on the electrical characteristics of the lamp such as the behaviour of the lamp conductance and spectral radiance. The analysis of the 577 nm mercury line’s response to the current pulse excitation allowed us to identify several phases. Good agreement has been found between simulation and experimental results.

A study of the impact of a High Pressure Sodium (HPS) lamps on power quality

Discharge lamps based on plasma emitting light are the most important electric light sources. They are used in virtually all areas of modern lighting technology and they are produced in wide range of powers with different levels of luminous efficacy. The main concern of lighting systems is their impact on power quality. The study proposed in this work is to measure power factor and harmonic disturbances generated by a 250W HPS lamp with magnetic ballast. An experimental setup is carried out to study the harmonic impact of large scale deployment of HID lamp. In addition, results obtained for these lamps are compared with those obtained for Compact Fluorescent Lamps (CFLs) widely used by electricity consumers in modern lighting and a simulation is also conducted using conductance model of High Intensity Discharge lamp.

High frequency electronic ballast for a high pressure metal halide lamp

The objective of this work is the study and realization of an electronic dimmable supply meant for the supply of light resources with high-intensity discharge lamps (HID) aimed to the public lighting network. We investigate the metal halide (mercury thallium iodide) discharge in a wide operating power range, the contribution of optically thick lines to radiation power of a cylindrical high pressure lamp, filled with Ar, Hg and TlI, was the subject of the analysis.

Effect of a pulsed power supply on the ultra violet radiation and electrical characteristics of low pressure mercury discharge

This work deals with the application of a pulsed power supply for pile driving of a low pressure mercury discharge (LPD). The influence of the pulsed current power supply on the electrical properties and the spectral radiant flux emitted by a germicidal UV lamp has been investigated, both experimentally and theoretically. A Self Consistent Collisional-Radiative model SCCR is described to understand the behavior of the plasma characteristics operated in a pulsed mode. This model includes elastic and inelastic processes as well as ambipolar diffusion. The output gives the whole macroscopic plasma properties such as the electric field strength, the electron temperature, the energy transfers of the various collision processes and the radiation output. To evaluate the energy emitted in the UV bandwidth, a photometric system composed of an integrating cylinder, UV radiometer, a spectrograph and a CCD camera is mounted. This study provides a framework for the design of a pulsed current power supply which features single or multiple pulses superimposed on a low-frequency square wave. Reasonable agreement has been obtained between the experimental data and the results of calculations which take the above processes into account.

Effect of a pulsed power supply on the ultraviolet radiation and electrical characteristics of a low-pressure mercury discharge

The influence of a pulsed-current power supply on the electrical properties and the spectral radiant flux emitted by a germicidal ultraviolet (UV) lamp has been investigated, both experimentally and theoretically. A self-consistent collisional–radiative model has been developed and used to model the temporal behaviour of the plasma characteristics of the lamp operated in the pulsed mode. The model includes elastic and inelastic processes as well as ambipolar diffusion. The macroscopic properties of the plasma, including the electron temperature, electric fields, radiation and energy transfer due to various collisional processes, have been considered. To evaluate the energy emitted in the UV bandwidth, a photometric system composed of an integrating cylinder, a UV radiometer, a spectrograph and a charge-coupled device camera is mounted. This study provides a framework for the design of a pulsed-current power supply, which permits the generation of a single pulse or multiple pulses superimposed on a low-frequency square wave.

Influence of the current invertor on the emission radiation of the low pressure mercury tubular discharge used in waste water treatment by U.V irradiation

The main purpose of the present work concerns the study of the influence of the current waveform on the radiant flux in U.V bandwidth of low pressure mercury tubular discharge. These lamps are used in waste water treatment by U.V irradiation. We elaborated an experimental setup consisting of a measuring device meant for the energy spectral flux. A current invertor delivering rectangular signals at variable frequency and duty cycle was set up.