This thesis presents a system approach to determine the existence of limit cycle oscillation and oscillating frequency of an inverter in self-oscillating electronic ballasts. As certain circuit's components in the lamp ballast system are nonlinear, Transfer functions of both forward and feedback path depend upon not only the operating frequency but also the amplitude of circuit's voltage and current. Exact system stability analysis is difficult to accomplish. Fundamental frequency approximation technique and linear lamp model were used to simplify the analysis. To calculate forward and feedback path frequency response, the amplitudes of both input and output voltage or current for each frequency must be specified. Starting from the general requirement for the existence of limit cycle oscillation, it was shown that only frequency response of load circuit phase-lag and feedback circuit phase-lead for a specified dc line voltage and linear load resistance is sufficient for the determination of the inverter operating frequency. The theoretical calculations were verified by computer simulations and experimental data.
