Harmonic Mitigation in 12-Pulse Bridge Rectifier Using DC Current Imposition Technique

Abstract

To enhance the ability of harmonic suppression in a 12-pulse diode bridge rectifier (DBR) using a DC side current imposition technique is proposed in this paper. The 12-pulse operation is achieved by a zigzag auto-connected transformer. The standard 12-pulse DBR does not satisfy the IEEE-519 standard and thus the current imposition technique can be used on the DC side to mitigate the input line current harmonic distortion. The current imposition circuit on DC side contains a doubler circuit along with the tapped interphase transformer (TIPT). The zigzag configured autoconnected transformer has the function to avoid zero sequence components and thereby expel the need for zero-sequence blocking transformer. When the multi-winding interphase reactor is designed optimally, the pulse number of load voltage can be increased from 12 to 24 and by using the TIPT the pulse number of output voltage can be further increased from 24 to 36. The proposed configuration is analyzed and simulated in the MATLAB Simulink and validated with hardware results. The results show that the proposed method improves the power quality by reducing the total harmonic distortion in the input line current.