Parameter Matching and Structural Optimization Design of H-SFCL in MMC Ship MVDC System

As a high-density and high-load system, ship DC system has the characteristics of short power supply line, low system damping. When a short-circuit fault occurs, it will cause serious damage and the direct current circuit breaker (DCCB) is required to cut off the fault current quickly. In our previous paper, a hybrid-type superconducting fault current limiter (H-SFCL) has been proposed, which can help DCCB reliably remove faults and realize fast reclosing. On this basis, the H-SFCL is selected and applied in ship medium voltage direct current (MVDC) system. In this paper, not only the current limiting principle of H-SFCL is introduced, but also its current limiting characteristics in modular multilevel converter (MMC) ship MVDC system are simulated and analyzed. In addition, the paraments selection and coil structural design of H-SFCL are optimized to improve the economy and ensure the safety and stability of the coil. Firstly, the parameter matching method is proposed based on the optimization algorithm in Matlab, and then the electromagnetic force coupling model in COMSOL is built to complete the structural optimization of the superconducting coil. The effectiveness of the optimization results is verified by stress analysis.