Total Harmonic Distortion Analysis of Front End Current for Diode Rectifier with Sepic Pfc

Front end current distortion of rectifier converter leads to low power factor, high THD, distribution system losses, neutral harmonic currents, over rated power equipments in a power system. In addition, the presence of harmonics in line currents may lead current distortion, create additional heating and over voltage problem, loading and losses in the utility distribution systems. The aim of this research is to develop a Sepic regulator with improved input current quality for low THD and good power factor to ensure better efficiency for the system. In this work, a detailed study has been carried out to investigate the effect of ac to dc converter on input current that eventually injects harmonics into the power system. Various topologies of the converter with input and output passive filter arrangements have been investigated and it has been found that passive filters no longer provide optimal THD, input power factor and efficiency. Finally, a single ended primary inductor converter (SEPIC) has been proposed. The performance of the SEPIC with and without passive filter has been investigated through ORCAD simulation. It is seen that SEPIC with input passive filter provides best performances in terms of THD, input power factor and efficiency for the rectifier arrangement.