A Reduced-Part-Number HID Lamp Electronic Ballast

This paper introduces a single power processing stage electronic ballast with reduced number of components to drive HID lamps. A DC-DC buck converter, which controls the current and the power of the lamp, a power factor pre-regulator based on discontinuous conduction mode boost converter and the inverter are combined in a BIBRED converter. It operates with a low frequency current driving the lamp. The signals of the power stages are provided by a dedicated microcontroller. Ballast for sodium vapor lamps of 70 W without acoustic resonance was implemented resulting in a pf = 0,97 with THD = 22% and eta = 84%.