An Ultralow-Loss Fault-Current-Limiting Z-Source LVDC Circuit Breaker Using Cryogenic Power Electronics

Abstract

Room-temperature power electronics based DC circuit breakers and fault current limiters face two major challenges: high conduction loss, and time-delayed response. This letter presents a novel circuitry, for the first time (based on literature studies), to combine cryogenic power electronics (CPE), together with the superconducting Z-source DC circuit breaker technology. The design, fabrication and tests of the new device were carried out, and 3 advantages were proved: (1) The actual overall system loss (including cryogenic issues) reduced by 62.1% in the 2 kW case study; (2) The no-delay automatic fault current limiting technology provided a sudden protective resistor ∼0.1 Ω to suppress the fault below 200 A, and meanwhile stabilized the bus voltage; (3) The CPE-based breaker achieved both the active device isolation and passive fault isolation within 60 μs.