D20.4 - A Low-Cost Multi-Port Hybrid Circuit Breaker with Common Solid-State Branch

This paper proposes a low-cost multi-port hybrid DC circuit breaker (MP-HCB) that uses a single solid-state branch (SS) shared across all protected ports, significantly reducing semiconductor usage and system cost. Each port employs a lightweight commutation path consisting of a pre-charged capacitor (PCC), a single auxiliary switch, and a diode string. During a fault, the PCC injects a reverse current that forces the mechanical-switch (MS) current to zero, enabling arcless interruption and minimizing conduction loss. A mathematical model is developed to guide PCC parameter selection and ensure reliable forced current zero-crossing. The proposed topology is evaluated through LTspice simulations and further validated experimentally using a 150-V, three-port hardware prototype. Measured results confirm fast current commutation, low voltage stress during MS opening, and reliable interruption of both single-port and simultaneous multi-port fault conditions. The architecture demonstrates a scalable and economically favorable protection solution for multi-terminal DC systems.