12.7kV ultra high voltage SiC commutated gate turn-off thyristor: SICGT

A novel 12.7 kV SiC SICGT (SiC commutated gate turn-off thyristor) was developed for on-line uses in power utility applications, which has the highest blocking voltage among the reported semiconductor switching devices. Its leakage current is low and is less than 1×10^-3 A/cm² at 9 kV and at 250°C. Its on-state voltage at 100 A/cm² is 6.6 V and is lower than that of a 9 kV Si GTO, which is composed of two 4.5 kV GTOs connected in series. Its turn-on time and turn-off time are 0.22 μs and 2.68 μs respectively, which are about 1/50 and 1/10 of a commercialized 6 kV 6 kA Si-GTO. A PWM half bridge inverter composed of SICGTs demonstrated an output voltage of ±1.25 kV and output power of 0.8 kVA respectively, which are the highest values among the reported SiC half bridge inverters.