100 A Solid State Circuit Breaker Using Monolithic GaN Bidirectional Switch with Two-Step Gate-Discharging Technique

We demonstrate a solid state circuit breaker (SSCB) using monolithic GaN bidirectional switch with two-step gate-discharging technique. A GaN bidirectional switch with dual-gate structure based on gate injection transistor (GIT) is employed to reduce on-state resistance instead of series-connected transistors which are commonly used. Furthermore, a two-step gate-discharging technique which prevents both short-circuit current and surge voltage from increasing during turn-off transient is proposed. The fabricated SSCB exhibits interruption for short-circuit current of 100 A under DC bus voltage of 380 V within 0.9 μs with no surge voltage. These results are attractive for DC circuit breakers in various application fields such as DC power distribution systems.

I. Introduction

DC power distribution systems in data centers, office buildings, and shipboards have been expected to achieve high efficiency, low cost and high reliability. Recently, the DC systems with 380V DC bus have emerged for high efficiency [1]. In such DC systems, solid state circuit breakers (SSCBs), which can interrupt fault current faster than mechanical breakers, are indispensable to protect power equipment connected to the power systems from short-circuit fault [2], [3]. Moreover, bidirectional SSCBs are needed to interrupt current flow in both directions [4].