Current‐Limiting Multi‐Port DC Circuit Breaker with Power Flow Control Function

Multi‐terminal flexible HVDC systems offer advantages such as absence of commutation failure and independent active/reactive power control. However, increasing system scale complicates DC power flow management. Building upon existing DC power flow control research, this paper proposes a novel multi‐port controller that integrates capacitor energy exchange with full‐bridge submodules. The presented topology—termed the Current‐limiting Multi‐port DC Circuit Breaker with Power Flow Control Function (CFC‐CLMPCB)—removes traditional dependence on line resistance adjustment for power flow regulation, thereby improving system reliability. A modular design is adopted to implement the control strategy across multiple ports. The working principle of the topology is first analyzed. Subsequently, its operation mode for clearing fault current during DC short‐circuit faults is examined. A control strategy based on port current variations is realized using pulse width modulation, with detailed analysis of the relationships among system state variables under this control mode. Finally, a four‐terminal flexible HVDC system model is constructed in Matlab/Simulink to validate the power flow control functionality of the proposed controller. The results confirm its effectiveness in managing power flow without relying on line resistance, while also providing fault current interruption capability. © 2026 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.