Power Factor Correction in Multi-pulse Rectifier Using Zigzag Auto-connected Transformer and Non-isolated SEPIC Converters

Abstract

To enhance the harmonic mitigation capability of the multi-pulse rectifier, this paper proposes a multi-pulse rectifier based on harmonic mitigation technology at DC link. The conventional 12-pulse rectifier does not meet the IEEE-519 standard and hence the active power factor correction technique is employed to mitigate the harmonics. The proposed system employs two diode bridge rectifiers, each followed by a SEPIC converter, by controlling the SEPIC converter inductor current, the input line current of the rectifier can be approximated to a sinusoidal waveform. A zigzag connected autotransformer is used as a phase-shift transformer in order to provide a phase shift and inherently blocks the zero sequence components. This method reduces the total harmonic distortion and also decreases the size of the system. The proposed configuration is analyzed and simulated in the MATLAB Simulink and also implemented in laboratory. The results show that the proposed method improves the power quality by reducing the total harmonic distortion (THD) in the input line current.