Control strategy for suppressing power oscillation of virtual synchronous generator under unbalanced grid voltage

Virtual synchronous generator (VSG) is grid-friendly for integrating distributed generations. However, traditional VSG control will lead to power oscillation under unbalanced grid voltage. To solve this problem, a VSG power oscillation suppressing control strategy is proposed. Firstly, the principle of VSG power fluctuation produced by the unbalanced grid voltage and its distinction from traditional inverter control are demonstrated. Then, a current reference calculation is achieved based on the features of VSG circuit in dq coordinate, which can reduce negative-sequence current under different types of unbalanced voltage. The calculation logic of the method is feasible and power fluctuation can be damped. Finally, the validity and effectiveness of the proposed control strategy is verified through the Matlab/Simulink simulation results.