15-kV single-bias all-optical ETO thyristor

A new all-optical emitter-turn-off (ETO) configuration is proposed in this paper which is operated under 15 kV single bias and a current of 10 A. This ETO is completely controlled by two optical signals, one for the 15 kV SiC gate-turn-off (GTO) thyristor and the other one for a triggering low-voltage optically controlled Si switch. The latter, called optically-triggered power transistor (OTPT), is used in series with the anode contact of the SiC GTO thyristor in order to handle the current switching between anode and gate path of the SiC GTO thyristor. This OTPT is triggered with a 5-W laser of 808-nm wavelength and the main SiC GTO thyristor is triggered with a laser having a low wavelength of 266 nm. The voltage drop on the OTPT during the on-state is controlled by the power of the laser. For an optical power of 5 W, the structure is optimized to have an on-state voltage of 0.2 V at the junction temperature of 200 °C. This is less than 0.002% of the total bias of 15 kV.