Ultrafast Solid-State Circuit Breaker With a Modular Active Injection Circuit

This article proposes a new modular active injection circuit (AIC) for solid-state circuit breakers (SSCB). The modular AIC is used to achieve soft switching turn-
off
during dc current interruption to mitigate the effects of the parasitic components in the main branch. The proposed AIC presents the following contributions: selectable resonant currents are achieved to obtain a reliable artificial zero-crossing point in dc currents; current rating scalability is provided; passive components of the AIC are optimized using particle swarm optimization (PSO) algorithm and new proposed objective functions; an external wireless charger is developed to charge the injection capacitor of the AIC to provide voltage isolation, compactness, and flexibility in choosing the precharge voltage value on the injection capacitor; the proposed AIC needs no discharge circuits, which simplifies the control and accelerates reclosing process. The proposed SSCB is simulated in a 6-kV system in power systems computer aided design/electromagnetic transients for dc (PSCAD/EMTDC) in interrupting currents of normal and different scenarios. The designed SSCB can interrupt the dc currents up to 200 A with the adaptive response time from 3.74 to 6.71 μs, faster response time in interrupting higher values of dc currents. The effectiveness of the proposed SSCB in practice is validated by experiments of a downsize 380 V/20 A prototype with only 2.8 μs response time and 99.91% efficiency.