6-in Dual-Gate Ring Commutated Thyristor for DC Circuit Breakers

DC circuit breakers (DCBs) are crucial components in dc power systems. The ultralow operating frequency of the DCBs enables the use of gate-commutated thyristors (GCTs) in the DCBs. This paper proposed a 6-in dual-gate ring commutated thyristor (DGRCT) for the DCB applications. The wafer and package designs of the DGRCT are first presented and discussed, analyzing the principles of the current commutation in the DGRCTs. Subsequently, a DGRCT prototype is fabricated, and experiments are conducted to measure the inductance along the current commutation loop (CCL) of the prototype DGRCT. Finally, a large current interruption experiment is conducted. The results show that the prototype DGRCT reduced the parasitic inductance within the CCL by at least 20% compared to conventional GCTs with single-gate ring design. The maximum current interruption capacity of the prototype DGRCT is no less than 12 kA at T = 300 K, which approaches the fault current interruption requirement in DCB applications for both transmission and distribution levels of dc power systems.