Thyristors with Low Circuit Commutated Turn-off Time for HVDC and FACTS

Electron and proton irradiation for carrier lifetime control was combined to reduce the circuit commutated recovery time tq. Using the latest generation of large area 7.2 kV / 6 kA Phase Control Thyristors for HVDC and other demanding applications, we show the impact of tq reduction on the technology curve between the ON-state voltage drop VT and recovery charge Qrr, as well as the limits of this reduction. A procedure for the best tq - VT relation for the range of VT below 2 V suitable for HVDC is proposed.