A Cost-Effective DC Breaker With Robust Breaking and Minimized Pulse Current

The series hybrid circuit breaker (SHCB) has emerged as a promising solution for protecting dc systems, as it addresses the slow breaking speed and high fault current surge associated with current commutation in traditional hybrid circuit breakers. However, SHCBs face several challenges, including a complex topology that complicates design and reduces reliability; a large pulse current in the voltage injection circuit, which imposes high current stress on the switching network and increases transformer size; and unreliable breaking performance under high line inductance, which may result in arcing. In this article, a cost-effective SHCB with robust breaking and minimized pulse current is proposed. First, the proposed SHCB employs a cost-effective single-coupling structure with a simplified topology and fewer components. Second, the design enables intermittent voltage injection (VI) through the single-coupling structure, reducing the pulse current in the VI circuit by approximately 20%. Third, the SHCB achieves robust breaking by isolating large line inductance through a robust breaking loop, providing reliable protection for dc systems. The operation principles, advantages, and design considerations are presented in detail and verified by scaled-down experiments.