Light flicker of fluorescent lamps with different types of ballasts caused by interharmonics
ABSTRACT The paper presents an analysis of the voltage fluctuations caused by interharmonics and its influence on luminous flux fluctuations of used combinations of fluorescent lamps and ballasts. One of the analysis results is a concept determining light sources sensitivity to such disturbing type based on frequency components utilization. Further a complex measured data file of sensitivity curves in various combinations of fluorescent lamps and ballasts are pointed. Measured and compared combinations include various types of fluorescent lamps, various wattages, modes of operation of the ballast and its specific designs and dimensioning of circuit elements etc.
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Article: A Light-flickermeter–Part I: Design[Show abstract] [Hide abstract]
ABSTRACT: Voltage variation is one of lamps flickering main cause; thus evaluation of a disturbing light flicker is a part of volt-age quality classification. The instrument for flicker level measurement by means of voltage variation analysis is named flickermeter and is specified in standard EN 61000-4-15. The flickermeter is a specialized analyzer modeling response of a chain consisting of reference 60W incandes-cent lamp – eye – brain of an average observer. Hence, other lamp types like discharge are mainly used in illumina-tion systems at present, significant difference between flicker measurement using the standard flickermeter and observation can appear. In the paper, there is proposed a light flicker measurement method based on analysis of an irradiance (radiant flux) waveform, where the output flicker index is independent on the lamp type. With regard to ex-pected properties the proposed light-flickermeter can be called objective flickermeter. Nevertheless the range of application of the objective flickermeter is limited as it is also shown.
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ABSTRACT: The IEC 61000-4-15 flickermeter has been widely accepted as an international standard for flicker severity measurement. In this paper, the implementation of an improved IEC flickermeter by an ARM microcontroller-based digital system with low cost and simple proposed prototype hardware is presented. The improvements include replacing a band-pass filter with a more appropriate filter and considering the model of various lamps. The operation of the improved flickermeter is evaluated in a simulated power system in Simulink of MATLAB software with its flicker source an arc furnace. Finally, a manipulated hardware for implementation of the improved flickermeter is proposed based on ARM microcontroller, and its performance is evaluated with some real-time experimental measurements.Transactions of the Institute of Measurement and Control 05/2013; 35(3). DOI:10.1177/0142331212439598 · 0.74 Impact Factor
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ABSTRACT: This paper proposes the luminance enhancement with low-frequency driving techniques for cold cathode fluorescent lamp (FL) (CCFL)-based lighting systems. The driver architecture features a full-bridge phase-shift inverter with a resonant tank and a three-winding step-up transformer to reduce leakage current, remove parasitic capacitance, enhance optical efficiency, balance and increase lamp uniformity, and achieve two-terminal high-voltage low-frequency driving of CCFLs. The low-frequency control of the driving technique is implemented in a field-programmable gate array controller to achieve luminance enhancement. The control strategy starts igniting the lamp with a high frequency and then reduces to low frequency in order to facilitate the linear increment of lamp brightness. Through the employment of this proposed approach, since the primary current of the transformers is only required, the circuit implementation can be completed with ease. Experimental results show that the proposed technique and control strategy help enhance luminance efficiency and reduce leakage current, demonstrating the practicality for the application considered.IEEE Transactions on Industrial Electronics 07/2014; 61(7):3279-3287. DOI:10.1109/TIE.2013.2278963 · 6.50 Impact Factor