A 4.5kV RC-IGCT with Diode Segmentation for MMC Inverters

Inhalt:
A 4.5 kV RC-IGCT for 4 kA, 3.2 kVDC was developed and tested with the aim of improving system efficiency for rail power supply applications using a full bridge MMC topology. The semiconductor losses were reduced by almost 40 % in the diode part and 5 % in the switch, an improvement facilitated by applying diode cathode segmentation. The resulting converter losses were reduced by some 10 %. This work describes the inner workings of diode cathode segmentation, addresses the balance-act required for trading off general performance parameters and – thanks to performing much of the testing in the target application’s MMC-cell-architecture – an accurate description on inverter performance of the new device.