Design for Low Power HB-LED Lighting

This paper presents an improved power quality converter (IPQC) based power supply design for high brightness Light Emitting Diode (HB-LED) low power lighting. The IPQC circuit uses a Cuk buck-boost converter to operate it in discontinuous conduction mode (DCM) using voltage follower technique for the mitigation of harmonic contents present in the AC mains current. Subsequently reduction in harmonic contents results in improving the power quality indices at AC mains. Single-stage single switch converter topology is used, which has less component count, size and cost as compared to two-stage converter topology. DCM operation has an advantage that only output voltage control loop is required as compared to three control loops required in continuous conduction mode operation. An 18 W LED driver is designed, modeled and simulated using MATLAB/Simulink software for 220V, 50 Hz AC mains. The performance of proposed LED driver is observed in terms of total harmonic distortion of input current (THDi), input power factor (PF) and crest factor (CF) keeping into account the strict international standard of IEC61000-3-2 for class C equipments. Keywords--Constant Voltage/Constant Current (CV/CC), LED lamp driver, Uncontrolled Bridge Rectifier (UBR), Power Factor Correction (PFC).