SEPIC PFC For Three Phase IM Drive Under Normal and Abnormal Supply Voltage

This paper presents the design and analysis of a Single-Ended Primary Inductor Converter (SEPIC) based Power Factor Correction (PFC) circuit for a three-phase induction motor (IM) drive operating under both normal and abnormal supply voltage conditions. The proposed system aims to improve the power quality by ensuring a near-unity power factor and maintaining a regulated DC link voltage, even in the presence of voltage sags, swells, or imbalances in the input supply. The SEPIC converter topology is selected for its inherent advantages, including the ability to both step-up and step-down the input voltage, continuous input current, and reduced electromagnetic interference (EMI). A control strategy combining a Phase Locked Loop (PLL) for synchronization and a dual-loop control for voltage and current regulation is implemented to achieve dynamic stability and robust performance. Simulation results validate the effectiveness of the proposed scheme in enhancing power factor, reducing total harmonic distortion (THD), and ensuring stable operation of the IM drive under a wide range of supply conditions. This study demonstrates the feasibility of employing SEPIC PFC converters in industrial motor drive systems where supply voltage fluctuations are common.