Reverse Blocking IGCTs for Current Source Inverters

Abstract

Today IGCTs (Integrated Gate Commutated Thyristors) are widely used for different applications especially voltage source inverters (VSIs) for which reverse conducting and asymmetric elements with discrete freewheeling diodes have been developed. For current source inverters (CSIs), reverse blocking elements are required and to this end symmetric 6 kV IGCTs have been developed. Using reverse blocking IGCTs in a CSI offers significant benefits compared to present GTO or thyristor solutions and allows higher inverter ratings and switching frequencies. In addition to the semiconductor switch, the performance of the integrated gate- driver has been adapted to the demands of the CSI. Status feedback signals for protection purposes and LEDs for easier commissioning of the drive have been incorporated and the gate-driver is optionally available with an AC power supply input allowing further system cost reductions.