Enhanced Power Decoupling Control for Virtual Synchronous Generator Considering Resistive-Inductive Line Impedance in Weak Grids

In the weak grids with complex resistive-inductive line impedance, the P-f and Q-U control are intertwined and highly coupled, which severely restricts the power delivery capability and dynamic support performance of VSG. To tackle this problem, an enhanced power decoupling control is proposed with two aspects: 1) Based on the analysis of power coupling mechanism under resistive-inductive line conditions, the intrinsic causes of dynamic power coupling and steady-state power delivery deviations are revealed; 2) A modified virtual impedance power decoupling method is proposed to eliminate the coupling between power loops, which can satisfy the conditions for dynamic power decoupling and power delivery demand simultaneously. The proposed method can effectively improve dynamic and steady power responses of VSG. Simulation tests are carried out to validate the proposed method.