HID Lamp Electronic Ballast Based on Chopper Converters

This paper proposes some topologies for developing electronic ballasts, supplying high-intensity discharge lamps fed by a pulsewidth-modulation ac-ac converter, implemented with bidirectional switches. The lamp operates directly from the ac mains; thus, operation with low frequency so as to prevent the occurrence of destructive acoustic resonance is provided. The features of the proposed solution are high efficiency, high power factor, low cost, and the absence of electrolytic capacitors. This paper includes the design of passive elements, the transfer function, and the development of the control strategy. The experimental results qualify the viability of the system feasibility.