Low Wattage Metal Halide Lamps Research Articles

Single-Switch Offline Ballast With PFC for Low-Wattage Metal Halide Lamps

This paper proposes a novel complete electronic ballast for low-wattage metal halide (LWMH) lamps. The lamp driver is based on the integration of a flyback power factor correction (PFC) input stage and a buck-boost inverter stage. The resulting circuit supplies the lamps with a high-frequency (HF) square current waveform, operating from the mains facility. The main feature of the proposed ballast is that through an adequate integration of the stages, the circuit operates with only one controlled switch. This switch is shared by the active PFC input stage, by the output HF inverter stage, as well as by the igniter. The control of the ballast is carried out by adjusting the maximum current through the switch and by fixing the duty ratio. Thus, the resulting output characteristic is suitable for a proper operation of these discharge lamps, including ignition, warm-up stage, and steady-state operation. The obtained HF square waveforms in the lamp avoid the apparition of acoustic resonances. A complete prototype has been built and tested, and experimental results are shown.

Acoustic Resonance Characterization of Low-Wattage Metal-Halide Lamps Under Low-Frequency Square-Waveform Operation

In this paper, a study about acoustic resonance (AR) in low-wattage metal halide lamps is presented. The lamps are supplied with a typical low frequency square waveform on which a high frequency sinusoidal ripple is superposed. The goal is to emulate the same waveforms generated by a low frequency electronic ballast. In this way, the ARs that appear in the lamp can be characterized against ripple amplitude and frequency. Different lamp's manufacturers and burning hours are used. The obtained results are intended to be employed in further reliable designs of low-frequency square-waveform electronic ballasts. An example of application of the accumulated AR signatures in this type of electronic ballasts is carried out, and a standard proposal is presented

Acoustic-Resonance Characterization of Low-Wattage Metal–Halide Lamps

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, a detailed study and experimentation on acoustic-resonances (AR) in low-wattage metal–halide lamps is presented. In order to excite the AR without extinguishing the electric arc, the lamps were supplied by means of a dc current with a superposed variable-frequency ac signal. By using this methodology, theoretical and experimental resonances were compared in terms of frequency, amplitude, and threshold-power level for their excitation. The experiments were carried out on four 35-W samples from each manufacturer (Osram and Philips), each of them with burning times of 100, 2500, and 5000 h, in order to cope with the full life of this type of lamps. AR maps for each lamp were obtained. These maps show not only the frequencies at which AR appear but also the amplitude of the resonances. The obtained AR maps are intended to be used by designers in order to know if a particular instantaneous lamp power waveform would be suitable to supply the lamp without generating AR. An application example on how to use these maps is also presented. </para>

New control strategy in a square-wave inverter for low wattage metal halide lamp supply to avoid acoustic resonances

High intensity discharge (HID) lamps are the most suitable when both high light power levels and good color rendering are researched. Some remarkable theoretical advantages would be obtained if these kinds of lamps were driven with high frequency (HF) electronic ballasts. Nevertheless, at these frequencies, acoustic resonances (AR) phenomenon appears. Low wattage metal halide (MH) lamps are, among all HID lamps, the most affected by this phenomenon. To obtain lack of AR in HID lamps, lamp power frequency harmonics must have a lower amplitude than a certain threshold value, related to activation energy. An electronic ballast may be designed to guarantee power harmonics levels lower than this threshold level at nominal operation. Nevertheless, the equivalent resistance of HID lamps varies highly in starting and warm-up stages, as well as in the aging process. Therefore, the system must be designed to be adequate for the necessary supplying conditions for these load variations. In this paper, a new control strategy for a HF square-wave inverter is presented. This ballast keeps lamp power harmonics at low levels, regardless of the lamp equivalent load. The proposed ballast, along with the control strategy, is presented, as well as the built prototypes and experimental results carried out. From these experiments, it can be concluded that the proposed method supplies low wattage MH lamps with lack of acoustic resonances.

Experimental study on acoustic resonance phenomena in ageing high-intensity discharge lamps

It is widely thought that ageing a metal halide (MH) lamp will result in changes in the acoustic resonance eigenfrequencies but to date no experimental data on this topic has been reported in the literature. A study on the influence of the operating time on the stability of low-wattage MH lamps is now presented. It is shown that the age of a lamp does not affect the fundamental acoustic eigenfrequency values. The upper limit of the frequency of the highest acoustic resonance band at which the arc will become unstable is not affected by the age of the lamp. However, the lamp age does influence the extent of instability inside the lamp with the lamp voltage significantly increasing

Minimization of Acoustic Resonances in HID Lamps: Analysis and Comparison of Power Harmonics Content in High Frequency Non-Resonant Inverters

Currently, the main drawback in high-intensity discharge lamps supplied by means of high-frequency (HF) electronic ballasts are the so-called acoustic resonances. In this paper, two HF nonresonant inverters for low wattage metal halide (MH) lamps are analyzed, from the point of view of its behavior regarding the acoustic resonances' phenomenon. Thus, a HF electronic ballast, operating with a lack of acoustic resonances, is proposed. From a dc voltage bus, the inverters provide an ac waveform to the lamp. The power stage operation of the inverters is first analyzed. Then, the characteristics of these waveforms are analyzed, from the point of view of minimizing the acoustic resonances' appearance. Then, upon these theoretical results, a comparison between inverters is done, selecting the most appropriate for lighting purposes. After that, a built prototype of the chosen inverter topology is presented, and the experimental results are shown. These experiments were carried out on several 70-W MH lamps. Finally, some conclusions are presented.

Lamp arc resistance modelling of high-intensity-discharge (HID) lamps

Based on a simplified approach to the prediction of acoustic resonance frequency distribution, a frequency-dependent lamp arc model of a low-wattage metal-halide (MH) lamp is presented. Verified with measurements, this approach provides a useful lamp-arc-resistance model for electronic ballast designers to predict and simulate the unstable frequency regions of high-intensity-discharge lamps and to design appropriate control for the ballast.

4000K Low Wattage Metal Halide Lamps with Ceramic Envelopes: A Breakthrough in Color Quality

4000K Low Wattage Metal Halide Lamps with Ceramic Envelopes: A Breakthrough in Color Quality

Low-Wattage Metal Halide Lamps with Enhanced Containment

Low-Wattage Metal Halide Lamps with Enhanced Containment

小形メタルハライドランプ用電子安定器の開発

小形メタルハライドランプ用電子安定器の開発

小形メタルハライドランプの高周波点灯における放電安定性

小形メタルハライドランプの高周波点灯における放電安定性

Ballasting the Miniature Metal Halide Lamp II

The need for a more efficeint compact light source has been with us for some time. Increased fuel costs have exaggerated the need. This paper deals with the development of a low wattage metal halide lamp and its system as an efficient compact light source. A lead circuit ballast in conjunction with a current sensitive starting switch is described. When used with the single-ended 40 watt lamp from a 120 volt line, an efficient, economical and reliable system results.

Direct Current Operation of Low Wattage Metal Halide Lamps

Direct Current Operation of Low Wattage Metal Halide Lamps

Ballasting the Miniature Metal Halide Lamp

The need for a more efficeint compact light source has been with us for some time. Increased fuel costs have exaggerated the need. This paper deals with the development of a low wattage metal halide lamp and its system as an efficient compact light source. A lead circuit ballast in conjunction with a current sensitive starting switch is described. When used with the single-ended 40 watt lamp from a 120 volt line, an efficient, economical and reliable system results.

Energy Balance of Low Wattage Single-Ended Metal Halide Lamps and the Method of Calculation of Discharge Capsule Size

A new approach to design of low wattage metal halide lamps has been used in order to minimize the end losses and to make the wall temperature more uniform. Using the method suggested by Elenbaas, the lamp's absolute total radiation was measured as a function of input power for discharge capsules of different sizes filled with mercury and sodium-scandium iodides. From this experimental data, the discharge thermal losses, i.e., that part of the lamp imput power which goes into heating the quartz capsule, were determined and applied in a thermal balance equation from which the quartz capsule dimensions were found for single-ended lamps of different wattages at a given wall temperature. The described method can be successfully used with only slight modifications for engineering calculations of other lamp types.