Supply system based on the 18-pulse diode rectifier with coupled reactors and integrated with the series active power filter

The article presents the principle of operation and selected results of simulation and laboratory tests of the 18-pulse converter system with direct voltage output, cooperating with a small series active power filter (S-APF). The presented system makes it possible to reduce, especially in autonomous supply networks, undesired higher harmonics in the network current. The 18-pulse nature of operation of the rectifier is reached using a set of coupled three-phase network reactors (CDT and CTR). Simultaneous use of the magnetically coupled reactors and the small active power filter provides opportunities for easy and cheap reduction of the supply current THD coefficient, down to the values acceptable by clean power converters (CPC) conditions.