Investigation of HID-lamp light emission differences for different power supply methods

Abstract

Abstract. This paper presents investigation of methods for reducing light pulsation and plasma temperature inside a high intensity discharge (HID) lamp arc tube. Differences found in light emission of an arc tube plasma channel under different power supply methods are presented and discussed in this work. The novelty of the paper lies in systematical investigation of different power converter supply methods and demonstrating that it has a significant influence on plasma temperature in an arc tube. The tested lamp was powered by electronic ballasts controlled by different algorithms, which forced their current waveform. To compare the results, the authors performed measurements on a discharge lamp powered by a standard electromagnetic ballast. The investigation of plasma parameters is based on the optical spectroscopy method. It was shown that by using the appropriate current shape of a high switching frequency supply converter, the plasma temperature of an HID lamp can be reduced almost by half.Key words: plasma temperature, electronic ballast, electromagnetic ballast, lamp current, light flux, light pulsation, high intensity discharge lamp.Investigation of HID-lamp light emission differences for different power supply methods Therefore, authors decided to perform a research determining the aforementioned parameters of an HID lamp. Plasma theoryPlasma is a source of optical radiation. One of the methods used to examine this state of matter is optical spectroscopy. The spectrum of plasma radiation carries a lot of information about atoms or ions, such as the type of gases used in discharge lamps, and the conditions in which they are located. All the processes taking place in radial plasma can be interpreted as a transition between two different quantum energy states. Processes involving the radiation of electrons and atoms (or ions) occur when an electron moves in an electrical field from one charged particle to another, usually an ion. As a result of its interaction with this particle, part of the path of the electron is curved. The temperature inside the arc tube of a discharge lamp is the parameter that determines the appropriate spectral distribution of the energy emitted by the plasma discharge, and the corresponding luminous efficiency. In the radiation spectrum of an HID lamp, there are a number of lines, characteristic of excited atoms. The shape of the spectral line reveals the conditions (pressure and temperature) prevailing in the discharge lamp. Fig. 1 shows a view of luminous plasma in a cold arc tube, whereas Fig. 2 shows luminous plasma in a hot arc tube.

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“…The study used LEDs, fluorescent tubes and an incandescent light bulb, with the power supplied respectively through dedicated power supply units, ballasts and directly from the mains. The paper [5] discusses other studies on light pulsation and plasma temperature in discharge lamps for different power supply methods [18]. Table 1 shows the symbols used for the light sources in this study.…”

Exploring the Feasibility of Autonomous Lighting Systems for Pedestrian Crossings in Off-Grid Areas

“…An extremely important issue related to extending the lifetime of light sources is the reduction in their operating temperature. In [31], four different ways of powering discharge light sources (HID) and their influence on the temperature of the plasma channel and emission of the luminous flux are presented. The study investigates the supply power of the discharge lamp using an electromagnetic ballast operating at a main frequency of 50 Hz and an electronic ballast, allowing the generation of different time waveforms of HID lamp currents.…”