A 12‐Pulse Star Rectifier With a Passive Auxiliary Injection Circuit at DC Link

ABSTRACT A simple 12‐pulse star rectifier using a new passive auxiliary injection circuit (PAIC) and a conventional double‐star rectifier is proposed in this paper. The proposed PAIC consists of a modified extended interphase reactor (MEIPR) with four diodes, and the PAIC is installed at the DC link. Four diodes in the PAIC extract the rectangular‐shaped current from the DC link and inject it into the load through MEIPR, which increase the levels of the output current and voltage of the double‐star rectifier. These changes double the output voltage's pulse number and the input line current's step number. When the tap points in the MEIPR are placed in the proper positions, the PAIC transforms the six‐pulse double‐star rectifier into the 12‐pulse star rectifier. The input line current THD value, determined from the experiment, is 8.09%. Four diodes in the PAIC are connected in parallel with the load, so the current stress and conduction loss are small, which means the proposed rectifier is suitable for low voltage and high current applications. A laboratory prototype has been constructed to experimentally validate the concept of the proposed 12‐pulse star rectifier.