Abstract: The gate-cathode structures of gate commutated thyristor (GCT) and gate turn-off thyristors are analyzed.Based on the commutation mechanism of a GCT during turn-off,a new design method for the gate-cathode layout of GCT is presented.Compared with the existing method,the new method increases the effective cathode area of GCT,decrease the thermal resistance,and improve the current capability under the precondition of uniform current distribution during turn-off.

Key words: power semiconductor devices, gate commutated thyristor, gate turn-off thyristor, gate-cathode structure