To enhance the inertia and damping at the ports of flexible interconnected AC/DC distribution networks under high penetration of renewable energy integration, this study proposes a control strategy for multi-terminal flexible interconnected distribution systems based on virtual synchronous generator and adaptive virtual dc generator (VSG-AVDG). Traditional virtual machine control methods merely combine VSG and virtual DC generator(VDG)controls in a simplistic manner, making it difficult to simultaneously suppress bus voltage fluctuations and improve dynamic performance. To address this limitation, the inherent relationship between virtual machine controls is analyzed, and a fusion mechanism coupling AC-side power deviation with DC-side voltage deviation is established, and a coordinated control strategy based on VSG-AVDG is proposed. On the AC side, an improved VSG control with DC outer-loop voltage compensation is adopted to reduce grid impact caused by mode switching and achieve load balancing. On the DC side, an AVDG control strategy suitable for flexible interconnected systems is designed to suppress bus voltage fluctuations while optimizing dynamic response. MATLAB/Simulink simulations demonstrate the validity and correctness of the proposed control strategy.
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