Introduction: Under the emerging scenario of widespread integration of DERs, the existing coordinated control strategies for multi-terminal flexible Direct Current (DC) distribution systems suffer from shortcomings such as a slow response speed and poor control performance, which ultimately lead to compromised system stability. Methods: This study proposes a novel coordinated control strategy based on fuzzy logic. This strategy enables real-time adjustment of system control variables, eliminates the adverse effects of fixed control variables on system performance, and significantly enhances the disturbance rejection capability of multi-terminal flexible DC distribution systems. Results: Compared with the existing coordinated control strategies, the coordinated control strategy proposed in this paper significantly reduces the DC voltage overshoot, DC voltage deviation, and the time required for the system to reach a steady state after being disturbed. Discussion: A fuzzy logic controller is innovatively introduced to perform real-time adjustment of the control variables in the system control process. When applied to different control systems, it only requires adjusting the corresponding scaling factors to convert the input and output variables into the universe of discourse, and the core part of the controller can be universally used. Conclusion: Compared with other coordinated control strategies, the proposed strategy exhibits superior performance in reducing DC voltage fluctuations, minimizing steady-state deviations, and shortening recovery time. Under three typical operating conditions, the DC voltage overshoot of the proposed strategy is reduced by 3.5%, 0.5%, and 2.6% respectively, respectively; the steady-state recovery time is shortened by 0.5, 0.32, and 0.6 seconds, respectively, and the steadystate voltage deviation is effectively reduced while avoiding system oscillation and instability.
Wang et al. (Wed,) studied this question.