A Novel 24-Pulse Diode Rectifier with an Auxiliary Single-Phase Full-Wave Rectifier at DC Side

A simple and robust 24-pulse diode rectifier for low-voltage and high-current applications is proposed in this paper. The proposed 24-pulse diode rectifier consists of a conventional four-star 12-pulse diode rectifier and an auxiliary single-phase full-wave rectifier (ASFR) installed at dc side. The low-power (3.4%Po) ASFR extracts two rectangular currents from the modified second-stage interphase transformer and injects a square current into the output of the rectifier system. This modification extends the conventional four-star 12-pulse operation to 24-pulse operation. The proposed 24-pulse rectifier draws near sinusoidal input line currents with the absence of 5th, 7th, 11th, 13th, 17th, and 19th harmonics. The average value of current through the ASFR has only 1.7% of load current, which means the current rating and conduction losses of ASFR are very small. The proposed scheme has low-diode conduction losses, and it is more suitable for low-voltage and large-current applications. Since only an additional ASFR is needed, the proposed scheme is low cost and simple to implement. The detailed analysis for the proposed rectifier is presented, and experimental results are provided to verify the proposed concept.