Multiport Thyristor-Based DC Solid-State Circuit Breaker With Soft Reclosing Capability

Thyristor-based dc solid-state circuit breakers (T-SSCBs) have been widely investigated due to their low losses and low cost. However, the current solutions are not cost-effective in dc microgrid because the number of auxiliary devices [e.g., auxiliary thyristors, capacitors and metal oxide varistors (MOVs)] will significantly increase in multiport scenario. In this article, a novel T-SSCB topology with the ability to expand the number of ports arbitrarily is proposed. Due to the adoption of integrated auxiliary branch structure, active turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> and soft reclosing of all ports are achieved by only one capacitor and one MOV. The concept of multiport T-SSCB (MT-SSCB) is proposed for the first time, the number of devices is significantly reduced compared to traditional T-SSCBs in multiport scenario. Moreover, the proposed MT-SSCB can eliminate MOV leakage current during <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> -state. As a result, the MT-SSCB presents advantages in low cost, small volume and high reliability. The operation principles and parameters designing are presented in detail. Experiment and comparative analysis verify the feasibility and effectiveness of the proposed MT-SSCB.