Cooperative Control Strategy of Virtual Synchronous Generator Based on Optimal Damping Ratio

Abstract

Wind power, photovoltaics and other new energy sources are connected to the grid on a large scale. The power electronic interface cannot provide inertia and damping support for the microgrid. The virtual synchronous generator technology is introduced into the inverter control system. Unlike the synchronous generator, its parameters are flexible and adjustable, which can enhance the robustness of the microgrid. This paper firstly analyzes the influence of the moment of inertia and damping on the system, it is based on the equivalent relationship between the three-phase inverter and the synchronous machine, combined with the VSG rotor motion equation, and conducts stability analysis based on the small signal model and root locus. Based on the existing control strategy, a virtual synchronous generator cooperative control strategy based on the optimal damping ratio is proposed. Finally, the VSG collaborative control model is built in MATLAB/Simlink, the experimental results show that the proposed control strategy effectively improves the transient performance of the VSG, the system active power overshoot is reduced from 5% to 0, and the frequency deviation peak is lowered from 0.174 Hz to 0.115 Hz, which confirms the effectiveness of the proposed control strategy.