Comparisons among self-excited parallel resonant, series resonant and current-fed push-pull electronic ballasts

Comparisons and examinations among self-excited parallel resonant, series resonant and current-fed push-pull electronic ballasts for fluorescent lamps in the aspects of soft starting, component stress, suitability of multi-lamp connection, variation of lumen under the operational condition of partial lamps extinguishment and/or removal, effect of lamp lifetime, inherence of short-/open-circuited protection, future expansion, double hot spots, lamp current crest factor and cost are presented in this paper. The operational principles and limitations of the aforementioned electronic ballasts are described qualitatively on which the comparison and examination of these aspects are, consequently, addressed. This work provides physical insight of electronic ballasts and furnishes thorough background knowledge for designers in selecting an appropriate one. The theoretical discussions and analyses are verified by experimental measurements