Design optimization of the LCC parallel-series inverter with resonant current mode controlfor 250-W HPS lamp ballast

In this paper, the optimum design of the LCC parallel-series inverter with resonant current mode control for 250-W high pressure sodium vapor lamps is presented. With this control method the inverter does not have any reactive energy, and both switching and conduction losses are minimized. Also, the design proposed performs a precise natural power control without exceeding the maximum power recommended by the lamp manufacturer without additional lamp power control circuitry. Since it is desirable implementing a low-cost and efficient power factor correction (PFC) stage for meeting the standard IEC 61000-3-2 Class C about low-frequency harmonic content injected in the line for lighting applications, a low-cost PFC buck pre-regulator is proposed. The ignition process is optimized because no additional circuitry is necessary for the lamp ignition providing low ignition inverter current. The design proposed leads to an important size and cost reduction, avoiding the additional circuitry used in the classic designs. Simulations and experimental results have validated the design proposed in this paper.