Analysis & design of high-frequency LCLC resonant converters for electrode-less fluorescent lamp ballasts

The paper describes methodologies for determining steady state operating conditions of 4^th order LCLC resonant power converters for application to electrode-less fluorescent lamp ballasts operating at 2.63 MHz. High frequency operation facilitates capacitive coupling into the tube and eases filtering for EMI, with near resonance operation at high load quality factor enabling high overall efficiency. Piecewise linear statespace models are derived and subsequently employed to rapidly predict the steady-state cyclic behaviour of the ballast during nominal operation without the pre-requisite of a transient-based simulation. The paper compares simulated and experimental measurements from a prototype ballast driving a 60cm, 8W, T5 fluorescent lamp to demonstrate prediction accuracy comparable to that of a SPICE simulation model, is possible.