Integrated Power Topologies to Supply HPS Lamps: A Comparative Study

This paper presents an integration methodology for dc/dc converters used to supply high-pressure sodium lamps with low-frequency square waveform (LFSW). The proposed electronic ballasts present high power factor, provided by the following input topologies: buck, boost, buck-boost, flyback, sepic, and zeta. These topologies are integrated with an output flyback converter, which controls the lamp current. This flyback converter is composed of one primary and two secondary windings, which are switched at low frequency, thus supplying the lamp with a LFSW current so that the acoustic resonances can be avoided. The proposed analysis applies the graft switch technique to obtain the integrated topologies. The ballasts´ design parameters and design procedure are also presented. Experimental results are shown in order to validate the theoretical analysis, and a comparison among the proposed topologies is performed.