Three-phase, two-switch PFC rectifier fed three-level VSI based FOC of induction motor drive

This paper presents a Scott transformer based three-phase, two-switch PFC (Power Factor Correction) boost rectifier for improving the power quality in a three-level diode clamped inverter (DCI) feeding indirect rotor field oriented control (FOC) based induction motor drive (IMD). Sinusoidal unity power factor source current and dc-link voltage regulation are achieved in the proposed rectifier only with two-switches. The three-level DCI is supplied by a split dc-link obtained from a Scott connected transformer feeding a rectifier. It is shown that a three-level DCI achieves reduced stator current with lower voltage harmonic content even at a lower switching frequency as compared to a two-level inverter. This results in reduction of voltage stress on motor windings for the same amount of torque ripple when indirect rotor FOC algorithm is implemented for the IMD. A MATLAB based simulation model of proposed PFC rectifier is developed for validating the design and to verify that the power quality issues in three-level DCI fed IMD are adequately addressed. The performance of the system is studied and compared with a conventional diode rectifier fed vector controlled IMD for different operating conditions of the drive.