Dissertação
Reator eletrônico auto-oscilante com alto fator de potência para alimentação de quatro lâmpadas fluorescentes independentes
Fecha
2004-02-27Autor
Dalla Costa, Marco Antônio
Institución
Resumen
This work describes a high-power-factor electronic ballast to supply four
fluorescent lamps independently. Fluorescent lamp operational aspects are
discussed, and a mathematical model to simulate the fluorescent lamp electric
characteristics is proposed. This model, based on exponential approximation, is
developed using experimental data. Multi-lamp arrangements are presented, and it
is chosen the best arrangement for the proposed work. To choose the best valleyfill
topology for passive power factor correction, theoretical and simulation analysis
are included, chosen topology has to meet the IEC 61000-3-2 Class C
requirements. A self-oscillating drive command modification is developed, in order
to drive the switches independently of the converter load. Also, it is presented a
simple circuit to correct the lamp current crest factor. Experimental results were
obtained in order to validate the proposed work; these results were obtained for the
ballast supplying four 32 W fluorescent lamps with switching frequency of 40 kHz,
and line voltage of 220 Vrms.