High Intensity Discharge Research Articles

Note: Measuring breakdown characteristics during the hot re-ignition of high intensity discharge lamps using high frequency alternating current voltage

To investigate the cold and hot re-ignition properties of High Intensity Discharge (HID) lamps in more detail an automated setup was designed in such a way that HID lamps of various sizes and under different background pressures can be tested. The HID lamps are ignited with a ramped sinusoidal voltage signal with frequencies between 60 and 220 kHz and with amplitude up to 7.5 kV. Some initial results of voltage and current measurements on a commercially available HID lamp during hot and cold re-ignition are presented.

Single‐stage high‐power‐factor low‐frequency square‐wave‐driven high‐intensity‐discharge lamp ballast

This study presents a single-stage electronic ballast for the high-intensity-discharge (HID) lamp with high-power factor. The presented ballast consists of a discontinuous-conduction-mode operated dual-boost converter to achieve input current shaping, and a high-frequency combined with a low-frequency square-wave-driven half-bridge-type inverter for supplying the HID lamp with low-frequency square-wave sources. The attractive features of the proposed ballast are high-power factor (> 0.99), low total harmonic distortion of input utility-line current (< 10%), high efficiency (> 90%), cost-effectiveness and freedom from acoustic resonance. The operational principles, design guidelines and a design example are included in this paper. A prototype ballast circuit has been successfully implemented and tested for supplying three different brands of 70W HID lamps operating with 110 V-root-mean-square input utility-line voltage. Satisfactory experimental results demonstrate the functionalities of the proposed ballast.

Spatiotemporal study of the local thermodynamic equilibrium deviations in high-intensity discharge lamps

The aim of this work is to study the local thermodynamic equilibrium (LTE) deviations in arc discharges plasma generated in high-intensity discharge lamps operating under an ac (50 Hz) power supply. To achieve this goal, we elaborate a two-temperature, two-dimensional, and time-depending model. We have found numerical results almost reproducing the experimental data, which allows us to validate this model. After validation, we have discussed different energy term effects on the LTE deviations.

Modified Flyback for HID Lamp Supply: Design, Modeling, and Control

This paper presents an electronic ballast for driving high intensity discharge (HID) lamps with low frequency square waveform from a dc supply. From the dc source (e.g., PFC rail), a flyback arrangement is inserted into a switching structure whose output provides low frequency voltage yet avoiding instability issues. Proposal's main advantage is the use of one single choke of simple assembly and only two active switches for current control and inversion. Converter design for DCM is presented in this work, besides an equivalent circuit from a control point of view. Small signal ac model is obtained and a feedback control loop is designed, based upon frequency response stability and performance analysis. HID dynamics is inserted into converter model, with feedback directly implemented. A prototype is presented and described in detail, consisting of a complete power and sensing circuit fully referenced to the switches common ground proposal. For design conformity, experimental and simulation results from Matlab and PSIM are presented, as well as discussions about the converter feasibility.

공진 점등 기능과 효율 향상을 위한 HID 램프의 저주파수 구형파 2단 전자식 안정기

In this paper, electronic ballast using resonant inverter for HID lamp is designed and implemented. The proposed electronic ballast is used the soft switching technology ZVS(Zero Voltage Switching) to reduce turn-on and turn-off loss. The ignition of proposed electronic ballast is achieved by controlling a full bridge inverter which is consisted of LC filter for resonance. After ignition the ballast operates as a low frequency square wave inverter by controlling a full bridge inverter as a buck converter. After ignition at resonant frequency of fo=160kHz, the switching frequency of a buck converter is consisted of 50kHz of high frequency and 170Hz of low frequency. This is for attenuating high frequency harmonics and avoiding acoustic resonance. The experimental results show that electronic ballast using resonant inverter is operated stably.

Size Reduction in Low-Frequency Square-Wave Ballasts for High-Intensity Discharge Lamps Using Soft-Saturation Magnetic Material and Digital Control Techniques

This paper presents an approach to reduce the size of low-frequency square-wave (LFSW) ballasts by using a single stage for resonant ignition and LFSW operation together with soft-saturation magnetic material and digital control techniques. Inductor design constraints are developed to leverage the nonlinear inductor behavior and achieve both size reduction and desirable performance in lamp ignition, warm-up, and normal operation modes. The digital controller provides multiple functions, including 1) a phase-controlled resonant sweep to achieve reliable lamp ignition and device protection with zero-voltage switching despite the nonlinear tank inductance, 2) lamp ignition detection and rapid transition to LFSW mode for lamp warm-up, 3) fast LFSW polarity transitions with optimal timing control for acoustic resonance free operation, and 4) two-loop feedback control. A fast current control loop limits and stabilizes the lamp current and rejects large ripple from the power factor correction (PFC) stage in order to reduce the size of the PFC output capacitor. A slow power control loop rejects variations in the lamp characteristics during warm-up and lamp aging. Experimental results are presented showing successful ignition and operation of a 150-W high-intensity discharge lamp.

Harmonics Injection in Hps Electronic Ballast With Modulation Index Control

&#x0D; The modulation index control is used in this work to control the lamp power supply permitting the removal of the output transformer out of the inverter-resonant filter setup. The Acoustic resonance in HPS lamps can be avoided by using a controlled PWM inverter and third harmonic injection. Experimental and simulation results are shown for the control of the inverter power subject to variation in the input voltage. Results for different DC bus voltages are also provided which attest the transformer removal and avoid the acoustic resonance with different modulation indexes. An ignitor for high-intensity discharge lamps, based on forced oscillation via an external periodic voltage square wave, supplied by a digitally controlled inverter, is also presented. The crest factor of the current can also be reduced by this approach.&#x0D;

Difference in Structural Relaxation Times of Inner Surface and Inner Bulk Region of Silica Glass Arc Tube

The fictive temperature and structural relaxation of a silica glass arc tube were investigated to elucidate the origin of cracking in the arc tubes used in high-intensity discharge lamps for vacuum ultraviolet light sources. The structural relaxation time near the inner surface was decreased much more than that in the inner bulk region, resulting in a large difference in the fictive temperature between these two areas at high-intensity discharge lamp operating temperatures. This difference should induce strain in the silica glass network. On the basis of our results, we suggest ways to avoid cracking and extend the lifetime of high-intensity discharge lamps.

Self-Reversed Scandium Lines as a Diagnostic Tool for Multicomponent HID Lamps

The analysis of plasma temperatures by self-reversed mercury lines is well established in the diagnostics of HID lamps. In mercury-free HID lamps or mercury containing lamps including a complex fill, however, the analysis of mercury lines could be impossible or difficult because additives may disturb the spectral line shape. This work analyzes the suitability of self-reversed scandium lines for temperature determination using Bartels method. Temperatures obtained by the three scandium lines analyzed here were found to agree very well with results from mercury lines, demonstrating their applicability as a diagnostic tool in multicomponent HID lamps.

Small gauge vitrectomy: Recent update

Small gauge vitrectomy, also known as minimally invasive vitreous surgery (MIVS), is a classic example of progress in biomedical engineering. Disparity in conjunctival and scleral wound location and reduction in wound diameter are its core principles. Fluidic changes include increased pressure head loss with consequent reduction in infusional flow rate and use of higher aspiration vacuum at the cutter port. Increase An increase in port open/port closed time maintains an adequate rate of vitreous removal. High Intensity Discharge (HID) lamps maintain adequate illumination in spite of a decrease in the number of fiberoptic fibers. The advantages of MIVS are, a shorter surgical time, minimal conjunctival damage, and early postoperative recovery. Most complications are centered on wound stability and risk of postoperative hypotony, endophthalmitis, and port site retinal break formation. MIVS is suited in most cases, however, it can cause dehiscence of recent cataract wounds. Retraction of the infusion cannula in the suprachoroidal space may occur in eyes with scleral thinning. As a lot has been published and discussed about sutureless vitrectomy a review of this subject is necessary. A PubMed search was performed in December 2011 with terms small gauge vitrectomy, 23-gauge vitrectomy, 25-gauge vitrectomy, and 27 gauge vitrectomy, which were revised in August 2012. There were no restrictions on the date of publication but it was restricted to articles in English or other languages, if there abstracts were available in English.

Measurable properties of Al2O3 ceramic injection molding raw materials

Powder injection molding (PIM), which encompasses metal injection molding (MIM) and ceramic injection molding (CIM), is a process which enables large scale production of complex-shaped components for use in a diverse range of industries. Ceramic injection molding (CIM) is a technology for manufacturing complex, precision, netshape components from ceramic powder. In the illuminant industry, for producing arc tube parts for high intensity discharge lamps the applied method is the ceramic injection molding. The ceramic arc tube parts are made of high purity alumina powder. By producing ceramic parts, one of the most critical steps is to optimize the injection molding process, to determine and control the influential machine parameters, which have an effect on the quality of the end product. Nevertheless, the properties of injection molding raw material is needed to be known before any optimization of the injection molding process, because later the molding process is optimized for this material, to decrease the amount of cracked ceramics. For producing ceramic arc tube parts (plugs), there are two different major components used for producing injection molding raw material (feedstock): high purity alumina powder as the main component, and an organic paraffin wax as a binder material. It is expressly important to know the physical and dimensional properties of the alumina powder, since mainly these have affect on the homogeneity and viscosity of feedstock, and therefore on the quality of the end product. In the present research, both the main components and the moldable raw material were investigated by visual, physical, chemical and thermal methods. It was found – most importantly – that the viscosity of the raw material linearly decreases with the increasing grinding time of the alumina powder. Applied analytical methods in terms of laser granulometry, tap density analysis, differential thermo-analysis and rheology analysis were used.

Transients analysis in a series oscillatory circuit

The article analyzes the transients in a series oscillatory circuit used to fire the high-intensity discharge lamps of DNaT type. The studies have shown that in the transient mode the voltage on the resonant fire capacitor can be several times higher than the voltage applied to the circuit. This mode is of practical interest for the fire of a lamp of DNaT type. The values of the circuit elements were chosen according to the L, r, C of the starting controller of the lamps of DNaT type. A similar phenomenon occurs when feeding both DC and AC voltages to the input of the chain under consideration. Therefore, to understand which form of voltage in the input of the starting controller is more preferable from the point of view of energy conservation, it is necessary to carry out the research and to determine the power consumption when feeding the constant and sinusoidal voltages to the input of the circuit

Electrodeless Mercury-Free Microwave-Driven Indium-Iodide-Based High-Intensity Discharges with High Color Rendering Index (June 2012)

In this paper, a method is shown to drive indium (I)-iodide-based discharges by microwaves in a compact setup. The microwave power is coupled into the discharge by a surfatron suitable for high-intensity discharges and small lamp diameters. A broad continuum in the spectral radiant flux of the lamps is shown at rather low pressures. High color rendering indexes were reached with color coordinates close to a thermal radiator. The dependence of the luminous flux on the lamps' filling condition is investigated. Buffering the discharge with elemental iodine decreases the discharges maintenance power.

Raman Scattering Spectroscopy for Historical Incandescent Lamps with a Carbon Filament, Hg-free HID Lamps and OLEDs

Raman Scattering Spectroscopy for Historical Incandescent Lamps with a Carbon Filament, Hg-free HID Lamps and OLEDs

Cost–benefit analysis of retrofit of high-intensity discharge factory lighting with energy-saving alternatives

Due to increased concern about overall energy costs and the appearance of efficient and inexpensive lighting system alternatives, factories and plants with high-intensity discharge (HID) lighting are forced to consider retrofit with more modern, energy-efficient lighting. The decision is complicated from an economic perspective, and there is a lack of information readily available on the topic. This study provides an analysis of the replacement by retrofit of common probe-start metal halide and high-pressure sodium industrial lighting systems. Retrofit options considered include the more recent pulse-start metal halide lamps and a range of T5 high output and T8 fluorescent lamp configurations. Recent data on lighting system pricing, labor and energy costs, and time required for tasks are reported. The results generated include savings, payback period, and net present value for many retrofit options, as well as the change in energy consumption, carbon footprint, and lumen output for each retrofit. Effects of varying rate of return and daily duration of operation are considered. Based on change in lumen output, payback period, net present value, and comparison of lighting quality, one or two options are recommended from the overall retrofit options considered. A fluorescent retrofit is recommended for each of the HID initial scenarios considered. The payback period is no more than 3 years in any recommended case. The focus of this study is on the potential energy and cost savings, and some proposed solutions may, or may not, be acceptable due to lack of illuminance uniformity.

RCCC calculations for electron scattering on quasi-two electron targets

We report on the recent extension of the RCCC method to accommodate electron scattering from quasi-two electron targets. We present results for electron scattering from mercury (Z = 80) which serves as a testing ground for relativistic theories due to its high atomic number. Furthermore electron-mercury scattering plays an important practical role in the physics of fluorescent and high intensity discharge lamps.

Analysis and Implementation of an HPF Electronic Ballast for HID Lamps With LFSW Voltage

In this paper, a novel high power-factor electronic ballast for metal-halide (MH) lamps based on integration of a buck-boost converter, a buck converter, and a full-bridge inverter is proposed. The buck-boost converter that serves as a power-factor corrector (PFC) is designed to operate at discontinuous conduction mode to achieve a high power factor at the input line. A bidirectional buck converter formed by a full-bridge inverter, an inductor, and a capacitor drives an MH lamp with a low-frequency square-wave voltage to prevent the lamp from acoustic resonance. The lamp power is controlled by adjusting the duty ratio of the active switches of the PFC. The circuit operation is analyzed in detail to derive the design equations. Circuit parameters are designed based on design considerations in practical applications. Finally, a prototype electronic ballast for a 70-W MH lamp is built and tested. Satisfactory performances are obtained from the experimental results.

Atomic gas temperature in a nonequilibrium high-intensity discharge lamp determined from the red wing of the resonance mercury line 254 nm

For developing low-wattage high intensity discharge (HID) lamps, a better understanding of the relatively unexplored nonequilibrium phenomena is essential. This needs interpretation of diagnostic results by methods free from equilibrium assumptions. In this paper, the atomic temperature is determined from the simulation of a quasistatic broadened resonance line by distinguishing between atomic temperature and excitation temperature in the equation of radiative transfer. The proposed method is applied to the red wing of the resonance mercury line 254 nm emitted from a HID lamp working on ac. The experimental results show severe deviation from local thermodynamic equilibrium. More than one thousand degrees difference was obtained between atomic and electron temperatures at the maximum current phase.

Walls et al. Respond

Bierman and Rea outlined some corrections and offered further information regarding the lighting sources described in our article. We welcome their comments and respond to each point as follows. First and second, Bierman et al. stated that high-intensity discharge (HID) and fluorescent lamps of similar wattage are approximately equal in terms of efficiency and that light-emitting diode (LED) lamps appear far brighter than fluorescent lamps. Although we welcome such advice, it was beyond the scope of our study to determine the particular characteristics of HID or LED lamps required in a work environment using fluorescent lamps to produce the required concentration and visual acuity. Third, the description of the range of correlated color temperatures (CCTs) available in fluorescent lamps in the United States is interesting, but as Bierman et al. did not comment on them, we can only note their advice as being useful. In our article, we stated that exposure to fluorescent lighting in the workplace has increased and that such exposure is to lights of higher CCT—those more appropriate for commercial and industrial use. Fourth, their point relating to the flicker of fluorescent lamps is informative and useful. It would be desirable for this type of information to be better understood by lamp manufacturers and suppliers. Fifth, Bierman et al. suggested it to be misleading to characterize actinic effects in terms of CCT. As referenced in our article, however, there is considerable evidence in the literature suggesting harm from ultraviolet (UV) emissions from some light sources, based on a specific combination of CCT and wavelength. Sixth, there may be no scientific consensus that lamps of higher CCT improve concentration or mental activity level. However, several studies,1–3 including a recent prospective controlled intervention study conducted in a “real-world” workplace setting,4 strongly suggest this is the case. In our study, we provided a crude estimate of the likely number of additional cases of cataracts and pterygia annually in Australia caused by increased exposure to fluorescent lighting, based on reported prevalence and population-attributable fractions. As such, we illustrated the importance of considering the possible health impacts of new technologies implemented to mitigate the effects of climate change.

Research on the Photometry and Corrosion Characteristics of Rare Earth Iodides in Ceramic Metal Halide Lamps

Rare earth iodides are commonly used in ceramic metal halide (CMH) lamps, a kind of high intensity discharge (HID) lamp. Rare earth metals in the discharge plasma inside the arc tube contribute to the superb performance of CMH lamps. On the other hand, however, polycrystal alumina (PCA) arc tube corrosion due to its reaction with rare earth iodides causes the deterioration of parameter maintenance, and constrains lifetime of the lamps. In this study, PCA arc tubes with specific rare earth iodides are prepared. Aging tests up to 2000 hours are conducted to evaluate the effects of single rare earth iodides on lamp performance. Also X-ray analysis shows the corrosion content of PCA arc tube by different rare earth iodides. The result shows that PCA tubes with single rare earth iodides are more corrosive than the mixture of various rare earth iodides.