An Optimal LCC Design Method for Dimmable Electronic Ballasts of the HID lamp

This paper proposes a new approach for designing an optimal LLC resonant inverter for electronic ballasts controlled by frequency variation. The proposed method calculates the resonant inverter´s optimal L, Cs and Cp values from the conditions obtained by analyzing normal and ignition operational statuses in the frequency range without acoustic resonance. Conditional equations that satisfy the maximum dimming range and the lamp ignition conditions were obtained by normal status analysis and ignition status analysis, respectively. The L, Cs and Cp values obtained by the proposed method were applied to a resonance inverter of the half bridge for a 250 W metal halide lamp, which verified the proposed approach´s validity.