An Analysis of Harmonic Emission from Compact Fluorescent Lamps Khodijah Mohamed, Hussain Shareef, Azah Mohamed Abstract – The main emphasis of this paper is on analyzing the harmonics generated from compact fluorescent lamps (CFLs). Laboratory tests on various CFLs were conducted to tap the load current behavior under different conditions. Then frequency domain analysis is performed to investigate the generated harmonics from CFLs. Harmonic levels of dimmable and non dimmable CFLs are experimentally evaluated and compared. The performance of dimmable CFLs and incandescent lamps at various brightness is also investigated. The results show that the dimmable CFLs produce more harmonics compared to incandescent lamps and non dimmable CFLs. Keywords: Compact Fluorescent Lamp, Dimming Function, Harmonic Analysis, THD Nomenclature AC Alternating current CFL Compact fluorescent lamp DC Direct current EMI Electromagnetic interference Fund Fundamental IC Integrated circuit IPC Industrial power corruptor P Active power PFC Power factor correction THD Total harmonic distortion THD I Current THD V AC AC voltage I. Introduction Compact fluorescent lamps (CFLs) combine the energy efficiency of fluorescent lighting with the convenience and popularity of incandescent fixtures. CFL use classical fluorescent discharge lamps with electronic ballast that feeds the gas-filled fluorescent tube, replacing the inductive starting element of the conventional system [1]. The fluorescent lamps equipped with electronic ballasts due to the lamp with electromagnetic ballast are more sensitive to voltage sags compared to those lamps with electronic ballast [2]. The aim of using electronic ballast is to increase the operating frequency of the system determined by the mains (50/60 Hz) to a few tens of kHz [3]. This give no time to the gas in the tube to de-ionize between current cycles, which lead to lower power consumption, longer tube life and almost no flicker. Also, the inductor required to generate a large overvoltage during starting is smaller and thus generates less resistive losses. Conversion of mains frequency into a considerably higher order in electronic ballast is the major source of harmonics generation in CFL. Harmonics are defined as the sinusoidal voltages or currents having frequencies that are integral multiples of the frequency at which the supply system is designed to operate [3], [6]. The deviation of waveform from perfect sinusoid is usually expressed in terms of harmonic distortion of the current and voltage waveforms. Since CFLs with electronic ballasts distort the current waveform by drawing short bursts of currents unlike in the case of incandescent lamp, it requires some form of power factor correction (PFC). However, PFC circuit is only available in compact fluorescent lamp with higher active power rating having not less than 25W. Furthermore, the electronic solution is more complex and traditionally they come with non dimmable feature. The majority of CFL available in the market cannot be used in conjunction with traditional light dimmers, in fact all these CFL carry a label which reads as “Not suitable for dimmers or electronics switches” for reminding the users. Recently, revolutionary new energy saving dimmable CFLs has been introduced with full control over light output. Dimming allows the ballast to control lamp power and thereby light output. The most common technique used in dimming, in general, is the phase control method in which the current is switched on for only part of the line cycle by a phase control dimming system. Due to this current chopping in dimmable ballasts, they create harmonic distortion on the service feeders. Although CFLs are not the only devices that create harmonics, the widespread adoption of CFLs and the combined effect of these small sources can be as detrimental as one large source. Besides is harder to mitigate because CFLs are distributed across the network