Improvement in harmonic reduction of zigzag autoconnected transformer based 12-pulse diode bridge rectifier by current injection at DC side

To improve the harmonic reduction ability in input line current of 12-pulse diode bridge rectifier (DBR) using zigzag autoconnected transformer with a dc side current injection technique is presented in this paper. Conventional 12-pulse rectifier does not meet the IEEE-519 standard and therefore current injection technique at dc side is used to shape the system current waveform to minimize the harmonic distortion in the input line current. The proposed configuration uses zigzag autoconnected transformer with inherent ability of blocking zero-sequence components which eliminate the requirement of zero sequence blocking transformer (ZSBT). The current injection circuit with interphase reactor (IPR) enables to alter dc current at the rectifier output which further shapes input line currents to near sinewave. The proposed configuration is designed, simulated and analyzed in MATLAB/SIMULINK. Simulation results of proposed configuration for variation in current injection and load on input line current harmonic suppression, power quality parameters are presented in this paper.