Proposing measures of flicker in the low frequencies for lighting applications

Lehman, Brad; Wilkins, Arnold J.; Berman, S.M.; Poplawski, Michael; Miller, Naomi

doi:10.1109/ecce.2011.6064154

Cited by 78 publications

(29 citation statements)

References 11 publications

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“…As shown in Figure 1.9, electronically balasted fluorescent lamps barely have any flicker. In [41], percent flicker is defined as Percent Flicker = 100…”

Section: Power Ripple and Flickermentioning

confidence: 99%

“…This effect is most severe in LEDs due to their relatively fast luminous response to power. Low frequency flicker can induce seizures in epileptics [20,41]. In others, it may induce headaches, eye strain, and a loss of concentration.…”

Section: Power Ripple and Flickermentioning

confidence: 99%

“…Flicker was discovered to be an issue with the introduction of the fluorescent lamp [20,41]. Early fluorescent lamps were magnetically ballasted and flickered at 120 Hz.…”

Section: Power Ripple and Flickermentioning

confidence: 99%

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An integrated multilevel converter with sigma delta control for LED lighting

Gerber

Kline

Sanders

et al. 2017

2017 IEEE Applied Power Electronics Conference and Exposition (APEC)

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High brightness LEDs have become a mainstream lighting technology due to their efficiency, life span, and environmental benefits. As such, the lighting industry values LED drivers with low cost, small form factor, and long life span. Additional specifications that define a high quality LED driver are high efficiency, high power factor, wide-range dimming, minimal flicker, and a galvanically isolated output. The flyback LED driver is a popular topology that satisfies all these specifications, but it requires a bulky and costly flyback transformer. In addition, its passive methods for cancelling AC power ripple require electrolytic capacitors, which have been known to have life span issues. This dissertation details the design, construction, and verification of a novel LED driver that satisfies all the specifications. In addition, it does not require a flyback transformer or electrolytic capacitors, thus marking an improvement over the flyback driver on size, cost, and life span.This dissertation presents an integrated circuit (IC) LED driver, which features a pair of generalized multilevel converters that are controlled via sigma-delta modulation. The first is a multilevel rectifier responsible for power factor correction (PFC) and dimming. The PFC rectifier employs a second order sigma-delta loop to precisely control the input current harmonics and amplitude. The second is a bidirectional multilevel inverter used to cancel AC power ripple from the DC bus. This ripple-cancellation module transfers energy to and from a storage capacitor. It uses a first order sigma-delta loop with a preprogrammed waveform to swing the storage capacitor voltage. The system also contains an output stage that powers the LEDs with DC and provides for galvanic isolation. The output stage consists of an H-bridge stack that connects to the output through a small toroid transformer.The IC LED driver was simulated and prototyped on an ABCD silicon test chip. Testing and verification indicates functional performance for all the modules in the LED driver. The driver exhibits moderate efficiency at half voltage. Although the part was only testable to half voltage, loss models predict that its efficiency would be much higher at full voltage. The driver also meets specifications on the line current harmonics and ripple cancellation.This dissertation introduces multilevel circuit techniques to the IC and LED research 2 space. The prototype's functional performance indicates that integrated multilevel converters are a viable topology for lighting and other similar applications.i Dedication Dedicated to my family and friends, who have been unwavering in their love and support.ii

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“…As shown in Figure 1.9, electronically balasted fluorescent lamps barely have any flicker. In [41], percent flicker is defined as Percent Flicker = 100…”

Section: Power Ripple and Flickermentioning

confidence: 99%

Section: Power Ripple and Flickermentioning

confidence: 99%

See 1 more Smart Citation

An integrated multilevel converter with sigma delta control for LED lighting

Gerber

Kline

Sanders

et al. 2017

2017 IEEE Applied Power Electronics Conference and Exposition (APEC)

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“…One of the parameters which determines the quality of light flux is its pulsation, and it depends on the method used to supply power to a given light source. Investigations of light flickering generated by light sources are presented in [5] and [6]. Another parameter which determines light emission is the plasma temperature.…”

Section: Introductionmentioning

confidence: 99%

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

Tomczuk

Mazurek

Hemka

et al. 2016

Bulletin of the Polish Academy of Sciences Technical Sciences

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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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“…As a consequence, the design should aim at high efficiency and high reliability as primary concerns [4]. As a consequence, a very common requirement imposed to these drivers is the absence of electrolytic capacitor in order to boost reliability and achieving a lifetime around 10 years [5,6].…”

Section: Introductionmentioning

confidence: 99%

An Overview of the AC-DC and DC-DC Converters for LED Lighting Applications

2012

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Original scientific paperHigh-Brightness Light Emitting Diodes (HB-LEDs) are considered the future trend in lighting not only due to their high efficiency and high reliability, but also due to their other outstanding characteristics: chromatic variety, shock and vibration resistance, etc. Nevertheless, they need the development of new power supplies especially designed for boosting and taking advantage of their aforementioned characteristics. Besides, their behaviour is completely different from the rest of lighting devices and, consequently, it should be also taken into account in the design of the converters used to drive them. As a result, many well-known topologies have been optimized or redesigned in order to be used in LED-lighting applications and many new topologies have come up in the recent years with the same purpose.In this paper, the main HB-LED characteristics will be explained, highlighting how they influence the design of their power supplies. After, the main topologies will be presented from the simplest to the most complex ones, analysing their advantages and disadvantages. Key words: AC-DC converters, DC-DC converters, LED, LightingPregled AC-DC i DC-DC pretvarača za primjene u LED rasvjeti. Svjetleće diode s visokom razinom svjetline (HB-LED) smatraju se budućim trendom u rasvjeti zahvaljujući ne samo visokom stupnju efikasnosti i pouzdanosti, nego i njihovim izvanrednim svojstvima: raznolikost boja, otpornost na udarce i vibracije i sl. Ipak, s ciljem potpunog iskorištenja prethodno spomenutih svojstava, potrebno je razviti nove, posebno osmišljene izvore napajanja. Osim toga, ponašanje im se posve razlikuje od ostalih tipova rasvjete što je potrebno uzeti u obzir pri projektiranju pretvarača za njihovo napajanje. Kao posljedica toga, mnoge su poznate topologije pretvarača optimirane ili preoblikovane posebno za primjenu u LED rasvjeti, a zadnjih nekoliko godina mnoge nove su se tek pojavile.U ovomčlanku objašnjena su osnovna HB-LED svojstva naglašavajući njihov utjecaj na razvoj izvora napajanja. Uz to, prikazane su osnovne topologije, od najjednostavnijih do najsloženijih, ujedno analizirajući prednosti i nedostatke pojedinih.

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Proposing measures of flicker in the low frequencies for lighting applications

Cited by 78 publications

References 11 publications

An integrated multilevel converter with sigma delta control for LED lighting

An integrated multilevel converter with sigma delta control for LED lighting

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

An Overview of the AC-DC and DC-DC Converters for LED Lighting Applications

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