Autotransformer rectifier circuits with parallel connection without the use of IPT chokes - review

When using many rectifying devices, higher harmonic components of currents absorbed by them from the grid become significantly important. They can cause very harmful phenomena connected with grid voltage drop, glimmering of lights or significant power losses. The presented 18 pulse rectifier circuits enable to lower the content of higher harmonics of the grid currents. When considering leakage inductance of autotransformers and supplying grid these rectifier circuits may be classified to the ‘clean power’ circuit type. Due to instability of ITP type chokes and their vulnerability to magnetic circuits saturation it was decided to resign from their application. Different 18 pulse rectifier circuits were analyzed and diode currents waveforms were calculated and their characteristic parameters were presented. These results may simplify the process of designing such circuits.