Cost-effective multi-pulse AC-DC converter with lower than 3% current THD

In this paper, a new multi-pulse clean power converter topology is presented with lower than 3% input current total harmonic distortion (THD). The topology is based on the combination of a 36-pulse converter and a pulse doubling circuit. The 36-pulse converter consists of a “polygon” autotransformer and two 18-pulse diode bridge rectifiers. Pulse doubling circuit consists of zero-sequence-blocking transformer (ZSBT) and tapped interphase transformer (IPT). The important advantage of the proposed AC-DC converter is considerable reduction in burdens of the magnetic parts with respect to the nominal load rating. It provides more economical solution to achieve harmonic mitigation in electric power systems as compared with other 72-pulse AC-DC converters. The simulation and experimental results show that the input current THD is less than 3% using the proposed topology. The results indicate a significant reduction in the total cost and volume of the proposed 72-pulse configuration in comparison with similar configurations. Also, it is shown that the proposed converter rating is about 44% of the DC load power.