An Advanced 4-inch IETO with Ultra-Low Commutation Impedance to Achieve 8 kA Turn-off Capability: Comprehensive Analysis, Design and Experiments

Compared with integrated gate commutated thyristors (IGCTs), an integrated emitter turn-off thyristor (IETO) has a potential of higher turn-off current capability and requires lower power consumption for gate driver units, which is more suitable for high-power applications. Thus in this paper, an advanced design of 4-inch IETO was presented. To reduce the gate commutation impedance and enhance the turn-off current, the turn-off circuit with low impedance DirectFETs was integrated into the housing. And the housing structure was carefully designed to provide a compact current commutation path. Then a 4-inch IETO prototype based on a 4.5 kV / 5 kA GCT wafer was developed. Experimental results shown that its maximum turn-off current was over 8.1 kA with an extremely short commutation time of 130 ns. And the total commutation inductance was only 0.38 nH. Additionally, the thermal and mechanical characteristics of the housing were also taken into consideration during design and verified by the thermal simulation and mechanical stress test. Consequently, according to this paper, IETO is potential to be a competitive device in high power applications in near future.