Three-phase SEPIC PFC for three-phase IM drive under unbalanced and distorted voltage supply

This paper proposes a three-phase power factor correction (PFC) for a three-phase induction motor (IM) drive under normal and abnormal supply voltage conditions. A new technique of PFC based on a positive sequence components method is introduced. The PFC circuit uses a SEPIC converter with a single switch, which needs only one control signal. The PFC control method with the proposed technique provides nearly sinusoidal supply currents maintaining a high power factor under different supply voltage conditions. Furthermore, the PFC method maintains DC bus voltage at the desired value. The regulated DC voltage feeds a four-switch inverter of the three-phase IM drive system. Mathematical analysis of the equivalent circuits based on operation modes of the SEPIC converter is introduced. The performance of the proposed technique is evaluated under ideal and non-ideal supply voltage conditions. The results are analyzed in terms of reduction in the THD of supply currents and improvement of power factor. System validation performed in simulation and experiment has shown the effectiveness of the proposed system under different supply voltage conditions.