Design and Implementation of Single Stage SEPIC Integrated Parallel Ripple Cancellation Method for LED Lighting

LED drivers when operating from a utility source with a diode bridge rectifier poses a higher output ripple which deserves a large capacitance. But, the higher value of capacitors, normally electrolytic, with lesser lifetime reduces the operating time. This paper proposes a single-ended primary inductor converter (SEPIC) with a front-end diode bridge rectifier integrated with a parallel ripple cancellation circuit (PRC) to eliminate the low frequency ac ripple with film capacitors to enhance the lifetime. The front-end SEPIC act as a power factor correction (PFC) circuit and is to be operated in discontinuous conduction mode (DCM) to attain an inherent PFC when fed from the utility source. A Bi-directional Buck-Boost converter is employed as a PRC circuit to ingest the low frequency ripple component and allow the pure dc to the load. The proposed topology exhibits a higher power factor and lesser output ripple with film capacitors of 10 uF, 22 uF compared to the electrolytic capacitors of a higher rating. Comparison is done based on the simulated results using PSIM and verified with an experimental setup of 30 W. The proposed LED driver topology demonstrates as input current Total Harmonic Distortion (THD) of 6.11, and power factor of 0.996.