Jörg Schwieger

HAW Hamburg | HAW · Department of Mechanical Engineering and Production

Today’s driver hardware for High-intensity discharge (HID) lamps is bulky, expensive and not particularly energy-efficient. A downscaling of the devices seems possible by increasing the operation frequency from typically 400 Hz to some hundred kilohertz. However, efforts to design high-frequency lamp-driver systems were not successful, since the pe...

The processes inside the arc tube of high-intensity discharge lamps are investigated by finite element simulations. The behavior of the gas mixture inside the arc tube is governed by differential equations describing mass, energy and charge conservation as well as the Helmholtz equation for the acoustic pressure and the Reynolds equations for the f...

Die Prozesse im Brenner von Halogen-Metalldampflampen werden mittels Finite-Element-Methode untersucht. Das Verhalten des Brennerinhalts wird durch insgesamt sieben gekoppelte Differenzialgleichungen beschrieben. Das Problem ist hochgradig nichtlinear. Eine direkte Lösung dieses Systems würde den Einsatz eines Hochleistungs-Computers erfordern. Es...

The processes inside the arc tube of high-intensity discharge lamps are inves- tigated by finite element simulations. The behavior of the gas mixture inside the arc tube is governed by differential equations describing mass, energy and charge conservation as well as the Helmholtz equation for the acoustic pressure and the Navier-Stokes equation for...

The processes inside the arc tube of high-intensity discharge (HID) lamps are investigated by finite element simulations. The behavior of the gas mixture inside the arc tube is governed by coupled differential equations describing mass, energy and charge conservation as well as the Helmholtz equation for the acoustic pressure and the Navier-Stokes...

With the help of COMSOL Multiphysics, we investigated the impact of acoustic resonances and the related acoustic streaming field on the operation of metal-halide discharge lamps. To our surprise, we found that the lamps exhibit behaviors that are similar to a well-known mechanical system — the forced Duffing oscillator with a softening spring.

The light flicker problem of high intensity discharge lamps is studied numerically and experimentally. It is shown that in some respects the systems behaves very similar to the forced Duffing oscillator with a softening spring. In particular, the jump phenomenon and hysteresis are observed in the simulations and in the experiments.

Operating high-intensity discharge lamps in the high frequency range (20-300 kHz) provides energy-saving and cost reduction potentials. However, commercially available lamp drivers do not make use of this operating strategy because light intensity fluctuations and even lamp destruction are possible. The reason for the fluctuating discharge arc are...

For energy efficiency and particularly for cost reduction it is preferred to drive high-intensity discharge lamps at frequencies of approximately 300 kHz. However, operating lamps at these high frequencies bears the risk of stimulating acoustic resonances inside the arc tube, which can result in low frequency light flicker and even lamp destruction...

Approximately one fifth of the world production of electric power is consumed for illumination [1]. High-intensity discharge (HID) lamps represent a main part of the artificial light sources. They are used for street and shop lighting as well as automobile headlights and other applications. A superior color rendering index combined with a sun-like...

For energy efficiency and material cost reduction it is preferred to drive high-intensity discharge lamps at frequencies of approximately 300 kHz. However, operating lamps at these high frequencies bears the risk of stimulating acoustic resonances inside the arc tube, which can result in low frequency light flicker and even lamp destruction. The ac...

A stationary compressible three-dimensional (3D) model of photothermal processes inside an arc tube of a high-intensity discharge lamp is developed on the basis of the finite element method. It takes plasma, electrodes, and the tube wall into account and enables simulation of acoustic phenomena. The temperature profile of the discharge arc is used...

For the reasons of energy efficiency and mate-rial cost reduction one would prefer to drive high-intensity discharge lamps at frequencies of about 300 kHz. Operat-ing lamps at these high frequencies bears the risk of stim-ulating acoustic resonances inside the arc tube, which can result in low frequency light flicker and even lamp de-struction. The...

Introduction: High-intensity discharge (HID) lamps will in the foreseeable future be important light sources despite a growing market share of LEDs. Cost and energy efficient high frequency (300 kHz) operation is hampered by the excitation of acoustic resonances inside the arc tube which results in low frequency (10 Hz) light flicker. Our aim is to...

High-intensity discharge lamps frequently suffer emission disturbances due to the excitation of acoustic resonances. This paper presents experimentally determined light flicker frequencies and arc motion frequencies at different excitation frequencies and modulation depths. Light intensity fluctuation has been detected with a photodiode. Simultaneo...

This work presents experimentally determined light flicker frequencies and arc motion frequencies of high-intensity discharge (HID) lamps at different excitation frequencies and modulation depths. Light intensity fluctuation has been detected with a photodiode. Simultaneously, arc motion was recorded with a camera. The frequencies of both methods a...

High-intensity discharge (HID) lamps comprise a translucent vessel called arc tube, in which a plasma discharge arc between two electrodes is established. These lamps combine high lumen efficacies with excellent color qualities. Operating HID lamps at a high-frequency (20 – 300 kHz) would reduce cost and increase energy efficiency of the lamp-drive...

High-intensity discharge (HID) lamps are energy-efficient light sources with excellent color qualities. These HID lamps are operated on low frequency square wave drivers with a high-frequency ripple. A cost reduction and efficiency step can be made by operating these lamps on high-frequency electronic ballasts [1]. However, these tend to excite aco...

High-intensity discharge (HID) lamps comprise a gas encapsulated in a transparent container called arc tube. The imposed alternating electric current results in a plasma discharge arc between the electrodes. This intensive heat source leads to a buoyancy driven velocity field. Tuning the modulation frequency to an acoustic Eigenfrequency of the arc...