Analysis of bridgeless converter model for power factor correction

Abstract

In this study, a novel single-stage bridgeless single-ended primary-inductor converter (SEPIC) model is designed to perform effective power factor correction while driving brushless direct current (BLDC) motors. The traditional SEPIC converter model produces a non-pulsating input current that operates with both conductors in a continuous-conduction mode(CCM). However, the proposed SEPIC converter is designed to function as an AC-DC converter; specifically, it is a cascade combination of the boost and buck-boost converters. Functionally, during discontinuous-condution mode (DCM), the boost converter becomes operational, whereas the buck-boost converter operates during the continuous-condution mode. Using the proposed SEPIC model, naturally the computed power factor is improved, which makes it employable for driving BLDC motors. During the implementation of the proposed model, the rotation of the permanent magnet BLDC motor was regulated through the continuous-conduction mode of operation of the bridgeless rectifier. On conducting both the simulation and hardware design process, comparisons were made based on the power factors obtained using the traditional buck-boost converters and those obtained using the SEPIC models presented herein. The SEPIC model proved its higher efficiency over the traditional converters from the viewpoint of the evaluated power factor values and minimized conduction losses. The newly modeled SEPIC model, which was designed for power factor correction, has been noted for its applicability in low power household applications. A power factor of 0.9 is obtained for the hardware implementation of the proposed converter, and a working model of the proposed converter is found to exhibit superior performance when compared with simulated models of the buck–boost converter and SEPIC.