Constant on time controlled zero voltage switching electronic ballast with power quality improvement

This study deals with the design, modelling and implementation of unity power factor (UPF) boundary conduction mode (BCM)-based electronic ballast for a T8, 36 W fluorescent lamp. In low power applications, BCM-based boost converter is widely used because of the low inductor value, however, because of zero crossover distortion, achieving a total harmonic distortion of <;10% is difficult for universal AC mains. In proposed electronic ballast, UPF has been achieved at universal AC mains by using a boost power factor corrected converter operating in BCM with constant on time control. The achieved constant DC-link voltage is converted into high frequency AC voltage using a quasi-half bridge series resonant inverter to initiate the discharge and also to drive the fluorescent lamp with constant current. The modelling and simulation of the proposed topology have been performed using sim power system tool-boxes in MATLAB-Simulink environment. The switching losses have been reduced by achieving zero voltage switching at an operating switching frequency of 46 kHz. Different evaluated parameters have been found as per the international standard IEC61000-3-2 of class C regulations.