A 28-pulse AC-DC converter for line current harmonic reduction

A novel transformer for 28-pulse AC-DC converter configuration is designed, modelled and simulated to feed isolated DC varying loads. The proposed transformer is suitable for large current rating rectifiers such as electric-aircraft power supply, electro-winning, electro-chemical processes, induction heating, plasma torches and so on, where isolation is required mainly for stepping down the supply voltage. It consists of two paralleled 14-pulse AC-DC converters involving seven-phase shifted AC fed diode bridges. It improves power quality at AC mains and it meets power quality IEEE-519 standards requirements at varying loads.